Phosphoric Acid Manufacturing and Phosphate Fertilizer Production RTR and Standards of Performance for Phosphate Processing, 66511-66590 [2014-25872]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 79, Number 216 (Friday, November 7, 2014)]
[Proposed Rules]
[Pages 66511-66590]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-25872]



[[Page 66511]]

Vol. 79

Friday,

No. 216

November 7, 2014

Part III





Environmental Protection Agency





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40 CFR Parts 60 and 63





Phosphoric Acid Manufacturing and Phosphate Fertilizer Production RTR 
and Standards of Performance for Phosphate Processing; Proposed Rule

Federal Register / Vol. 79 , No. 216 / Friday, November 7, 2014 / 
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60 and 63

[EPA-HQ-OAR-2012-0522; FRL-9912-61-OAR]
RIN 2060-AQ20


Phosphoric Acid Manufacturing and Phosphate Fertilizer Production 
RTR and Standards of Performance for Phosphate Processing

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing 
amendments to the National Emission Standards for Hazardous Air 
Pollutants for the Phosphoric Acid Manufacturing and Phosphate 
Fertilizer Production source categories and to new source performance 
standards (NSPS) for several phosphate processing categories. The 
proposed amendments address the results of the residual risk and 
technology reviews (RTR) conducted as required under the Clean Air Act 
(CAA), as well as other actions deemed appropriate during the review of 
these standards. The proposed amendments include numeric emission 
limits for mercury and work practice standards for hydrogen fluoride 
(HF) from calciners; work practice standards for hazardous air 
pollutant (HAP) emissions from gypsum dewatering stacks and cooling 
ponds; emission standards requiring HF testing from various affected 
sources; clarifications to the applicability and monitoring 
requirements for both source categories to accommodate process 
equipment and technology changes; changes to remove the exemptions for 
startup, shutdown and malfunction; work practice standards for periods 
of startup and shutdown; and revised provisions to address 
recordkeeping and reporting requirements applicable to periods of 
startup, shutdown and malfunction. The proposed amendments will reduce 
mercury emissions, thereby reducing potential mercury exposure to 
children, including the unborn. Further, the EPA has conducted an 8-
year review of the current NSPS for these source categories, and is 
proposing that no revisions to the numeric emission limits for these 
standards are appropriate.

DATES: Comments. Comments must be received on or before December 22, 
2014. A copy of comments on the information collection provisions 
should be submitted to the Office of Management and Budget (OMB) on or 
before December 8, 2014.
    Public Hearing. If anyone contacts the EPA requesting to speak at a 
public hearing by November 12, 2014, we will hold a public hearing on 
November 24, 2014 on the EPA campus at 109 T.W. Alexander Drive, 
Research Triangle Park, North Carolina.

ADDRESSES: Comments. Submit your comments, identified by Docket ID 
Number EPA-HQ-OAR-2012-0522, by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov: 
Follow the online instructions for submitting comments.
     Email: A-and-R-Docket@epa.gov. Include Attention Docket ID 
No. EPA-HQ-OAR-2012-0522 in the subject line of the message.
     Fax: (202) 566-9744, Attention Docket ID No. EPA-HQ-OAR-
2012-0522.
     Mail: Environmental Protection Agency, EPA Docket Center 
(EPA/DC), Mail Code 28221T, Attention Docket ID No. EPA-HQ-OAR-2012-
0522, 1200 Pennsylvania Ave. NW., Washington, DC 20460. In addition, 
please mail a copy of your comments on the information collection 
provisions to the Office of Information and Regulatory Affairs, Office 
of Management and Budget (OMB), Attn: Desk Officer for EPA, 725 17th 
Street NW., Washington, DC 20503.
     Hand/Courier Delivery: EPA Docket Center, Room 3334, EPA 
WJC Building, 1301 Constitution Ave. NW., Washington, DC 20004, 
Attention Docket ID Number EPA-HQ-OAR-2012-0522. Such deliveries are 
only accepted during the Docket's normal hours of operation, and 
special arrangements should be made for deliveries of boxed 
information.
    Instructions. Direct your comments to Docket ID Number EPA-HQ-OAR-
2012-0522. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at https://www.regulations.gov, including any personal 
information provided, unless the comment includes information claimed 
to be confidential business information (CBI) or other information 
whose disclosure is restricted by statute. Do not submit information 
that you consider to be CBI or otherwise protected through https://www.regulations.gov or email. The https://www.regulations.gov Web site 
is an ``anonymous access'' system, which means the EPA will not know 
your identity or contact information unless you provide it in the body 
of your comment. If you send an email comment directly to the EPA 
without going through https://www.regulations.gov, your email address 
will be automatically captured and included as part of the comment that 
is placed in the public docket and made available on the Internet. If 
you submit an electronic comment, the EPA recommends that you include 
your name and other contact information in the body of your comment and 
with any disk or CD-ROM you submit. If the EPA cannot read your comment 
due to technical difficulties and cannot contact you for clarification, 
the EPA may not be able to consider your comment. Electronic files 
should not include special characters or any form of encryption and be 
free of any defects or viruses. For additional information about the 
EPA's public docket, visit the EPA Docket Center homepage at: https://www.epa.gov/dockets.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID Number EPA-HQ-OAR-2012-0522. All documents in the docket are 
listed in the https://www.regulations.gov index. Although listed in the 
index, some information is not publicly available, e.g., CBI or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, is not placed on the Internet 
and will be publicly available only in hard copy. Publicly available 
docket materials are available either electronically in https://www.regulations.gov or in hard copy at the EPA Docket Center, Room 
3334, EPA WJC West Building, 1301 Constitution Avenue NW., Washington, 
DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday 
through Friday, excluding legal holidays. The telephone number for the 
Public Reading Room is (202) 566-1744, and the telephone number for the 
EPA Docket Center is (202) 566-1742.
    Public Hearing. If anyone contacts the EPA requesting a public 
hearing by November 12, 2014, the public hearing will be held on 
November 24, 2014 at the EPA's campus at 109 T.W. Alexander Drive, 
Research Triangle Park, North Carolina. The hearing will begin at 10:00 
a.m. (Eastern Standard Time) and conclude at 5:00 p.m. (Eastern 
Standard Time). There will be a lunch break from 12:00 p.m. to 1:00 
p.m. Please contact Ms. Pamela Garrett at 919-541-7966 or 
garrett.pamela@epa.gov to register to speak at the hearing, or to 
inquire about whether a hearing will be held. The last day to pre-
register in advance to speak at the hearings will be November 19, 2014. 
Additionally, requests to speak will be taken the day of the hearing at 
the hearing registration desk, although preferences on speaking times 
may not

[[Page 66513]]

be able to be fulfilled. If you require the service of a translator or 
special accommodations such as audio description, please let us know at 
the time of registration. If you require an accommodation, we ask that 
you pre-register for the hearing, as we may not be able to arrange such 
accommodations without advance notice.
    The hearing will provide interested parties the opportunity to 
present data, views or arguments concerning the proposed action. The 
EPA will make every effort to accommodate all speakers who arrive and 
register. Because this hearing is being held at U.S. government 
facilities, individuals planning to attend the hearing should be 
prepared to show valid picture identification to the security staff in 
order to gain access to the meeting room. Please note that the REAL ID 
Act, passed by Congress in 2005, established new requirements for 
entering federal facilities. If your driver's license is issued by 
Alaska, American Samoa, Arizona, Kentucky, Louisiana, Maine, 
Massachusetts, Minnesota, Montana, New York, Oklahoma or the state of 
Washington, you must present an additional form of identification to 
enter the federal building. Acceptable alternative forms of 
identification include: Federal employee badges, passports, enhanced 
driver's licenses and military identification cards. In addition, you 
will need to obtain a property pass for any personal belongings you 
bring with you. Upon leaving the building, you will be required to 
return this property pass to the security desk. No large signs will be 
allowed in the building, cameras may only be used outside of the 
building and demonstrations will not be allowed on federal property for 
security reasons.
    The EPA may ask clarifying questions during the oral presentations, 
but will not respond to the presentations at that time. Written 
statements and supporting information submitted during the comment 
period will be considered with the same weight as oral comments and 
supporting information presented at the public hearing. Commenters 
should notify Ms. Garrett if they will need specific equipment, or if 
there are other special needs related to providing comments at the 
hearings. Verbatim transcripts of the hearing and written statements 
will be included in the docket for the rulemaking. The EPA will make 
every effort to follow the schedule as closely as possible on the day 
of the hearing; however, please plan for the hearing to run either 
ahead of schedule or behind schedule.
    Again, a hearing will only be held if requested by November 12, 
2014. Please contact Ms. Pamela Garrett at 919-541-7966 or at 
garrett.pamela@epa.gov or visit https://www.epa.gov/ttn/atw/phosph/phosphpg.html to determine if a hearing will be held. If the EPA holds 
a public hearing, the EPA will keep the record of the hearing open for 
30 days after completion of the hearing to provide an opportunity for 
submission of rebuttal and supplementary information.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Ms. Tina Ndoh, Sector Policies and Programs Division 
(D243-02), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-2750; fax number: (919) 541-5450; 
and email address: Ndoh.Tina@epa.gov. For specific information 
regarding the risk modeling methodology, contact James Hirtz, Health 
and Environmental Impacts Division (C539-02), Office of Air Quality 
Planning and Standards, U.S. Environmental Protection Agency, Research 
Triangle Park, North Carolina 27711; telephone number: (919) 541-0881; 
fax number: (919) 541-0359; and email address: Hirtz.James@epa.gov. For 
information about the applicability of the national emissions standards 
for hazardous air pollutants (NESHAP) or the NSPS to a particular 
entity, contact Scott Throwe, Office of Enforcement and Compliance 
Assurance, U.S. Environmental Protection Agency, William Jefferson 
Clinton Building, Mail Code 2227A, 1200 Pennsylvania Avenue NW., 
Washington, DC 20460; telephone number: (202)562-7013; and email 
address: Throwe.Scott@epa.gov.

SUPPLEMENTARY INFORMATION: 

Preamble Acronyms and Abbreviations

    We use multiple acronyms and terms in this preamble. While this 
list may not be exhaustive, to ease the reading of this preamble and 
for reference purposes, the EPA defines the following terms and 
acronyms here:

ACI Activated Carbon Injection

AEGL Acute exposure guideline levels
AERMOD Air dispersion model used by the HEM-3 model
AFPC Association of Fertilizer and Phosphate Chemists
AOAC Association of Official Analytical Chemists
APF Ammonium phosphate fertilizer
BACT Best available control technology
BDL Below the method detection limit
BSER Best System of Emissions Reduction
CAA Clean Air Act
CalEPA California EPA
CA-REL California Reference Exposure Level
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CEMS Continuous emissions monitoring system
CFR Code of Federal Regulations
CMS Continuous monitoring system
CPMS Continuous parameter monitoring system
DAP Diammonium phosphate
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guidelines
ERT Electronic Reporting Tool
F Fluoride
FaTE Fate, Transport, and Ecological Exposure
FR Federal Register
FTIR Fourier transform infrared spectroscopy
gr/dscf Grams per dry standard cubic feet
GTSP Granular triple superphosphate
H Hydrogen
HAP Hazardous air pollutants
HCl Hydrogen chloride
HEM-3 Human Exposure Model, Version 1.1.0
HF Hydrogen fluoride
Hg Mercury
HI Hazard index
HQ Hazard quotient
ICR Information Collection Request
IRIS Integrated Risk Information System
km Kilometer
LAER Lowest achievable emissions rate
LOAEL Lowest-observed-adverse-effect level
MACT Maximum achievable control technology
MAP Monoammonium phosphate
mg/dscm Milligrams per dry standard cubic meter
mg/kg-day Milligrams per kilogram-day
mg/m\3\ Milligrams per cubic meter
MIBK Methyl isobutyl ketone
MIR Maximum individual risk
MRL Minimum risk level
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NATA National Air Toxics Assessment
NEI National Emissions Inventory
NESHAP National Emissions Standards for Hazardous Air Pollutants
NOAA National Oceanic and Atmospheric Administration
NOAEL No-observed-adverse-effect level
NRC National Research Council
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OECA Office of Enforcement and Compliance Assurance
OMB Office of Management and Budget
P2O5 Phosphorus pentoxide
PB-HAP Hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PEL Probable effect levels
PM Particulate matter
POM Polycyclic organic matter
PPA Purified phosphoric acid
ppm Parts per million

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QA/QC Quality assurance/quality control
RACT Reasonably available control technology
RATA Relative accuracy test audit
RBLC RACT/BACT/LAER Clearinghouse
REL Reference exposure level
RFA Regulatory Flexibility Act
RfC Reference concentration
RfD Reference dose
RTR Residual risk and technology review
SAB Science Advisory Board
SBA Small Business Administration
SiF4 Silicon tetrafluoride
SPA Superphosphoric acid
SSM Startup, shutdown and malfunction
TOSHI Target organ-specific hazard index
tpy Tons per year
TRIM Total Risk Integrated Modeling System
TRIM.FaTE Total Risk Integrated Methodology.Fate, Transport, and 
Ecological Exposure model
TTN Technology Transfer Network
UF Uncertainty factor
[mu]g/m\3\ Micrograms per cubic meter
UMRA Unfunded Mandates Reform Act
UPL Upper prediction limit
URE Unit risk estimate
VCS Voluntary consensus standards
WESP Wet electrostatic precipitator
WPPA Wet-process phosphoric acid
WWW World Wide Web

    Organization of this Document. The information in this preamble is 
organized as follows:

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
    C. What should I consider as I prepare my comments for the EPA?
II. Background
    A. What are the statutory authorities for this action?
    B. What are the source categories and how do the current NESHAP 
and NSPS regulate emissions?
    C. What data collection activities were conducted to support 
this action?
    D. What other relevant background information and data are 
available?
III. Analytical Procedures
    A. How did we estimate post-MACT risks posed by the source 
categories?
    B. How did we consider the risk results in making decisions for 
this proposal?
    C. How did we perform the technology reviews for the NESHAP and 
NSPS?
IV. Analytical Results and Proposed Decisions for the Phosphoric 
Acid Manufacturing Source Category
    A. What actions are we taking pursuant to CAA sections 112(d)(2) 
and 112(d)(3) for the Phosphoric Acid Manufacturing source category?
    B. What are the results of the risk assessment and analyses for 
the Phosphoric Acid Manufacturing source category?
    C. What are our proposed decisions regarding risk acceptability, 
ample margin of safety and adverse environmental effects for the 
Phosphoric Acid Manufacturing source category?
    D. What are the results and proposed decisions based on our 
technology review for the Phosphoric Acid Manufacturing source 
category?
    E. What other actions are we proposing for the Phosphoric Acid 
Manufacturing source category?
    F. What are the notification, recordkeeping and reporting 
requirements for the Phosphoric Acid Manufacturing source category?
    G. What compliance dates are we proposing for the Phosphoric 
Acid Manufacturing source category?
V. Analytical Results and Proposed Decisions for the Phosphate 
Fertilizer Production Source Category
    A. What are the results of the risk assessment and analyses for 
the Phosphate Fertilizer Production source category?
    B. What are our proposed decisions regarding risk acceptability, 
ample margin of safety and adverse environmental effects for the 
Phosphate Fertilizer Production source category?
    C. What are the results and proposed decisions based on our 
technology review for the Phosphate Fertilizer Production source 
category?
    D. What other actions are we proposing for the Phosphate 
Fertilizer Production source category?
    E. What are the notification, recordkeeping and reporting 
requirements for the Phosphate Fertilizer Production source 
category?
    F. What compliance dates are we proposing for the Phosphate 
Fertilizer Production source category?
VI. Summary of Cost, Environmental and Economic Impacts
    A. What are the affected sources?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
VII. Request for Comments
VIII. Submitting Data Corrections
IX. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination with 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children from 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the industrial source categories 
that are the subject of this proposal. Table 1 is not intended to be 
exhaustive but rather to provide a guide for readers regarding the 
entities that this proposed action is likely to affect. The proposed 
standards, once promulgated, will be directly applicable to the 
affected sources. As defined in the ``Initial List of Categories of 
Sources Under Section 112(c)(1) of the Clean Air Act Amendments of 
1990'' (see 57 FR 31576, July 16, 1992), the ``Phosphoric Acid 
Manufacturing'' source category is any facility engaged in the 
production of phosphoric acid. The category includes, but is not 
limited to, production of wet-process phosphoric acid (WPPA) and 
superphosphoric acid (SPA). The ``Phosphate Fertilizer Production'' 
source category includes any facility engaged in the production of 
phosphate-based fertilizers including, but not limited to, plants with 
bulk-blend processes, fluid-mix processes or ammonia granulation 
processes. Examples of phosphate fertilizers are: Monoammonium 
phosphates (MAP) and diammonium phosphates (DAP) (or ammonium phosphate 
fertilizer (APF)), and triple superphosphates (TSP).\1\
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    \1\ U.S. EPA. Documentation for Developing the Initial Source 
Category List--Final Report, USEPA/OAQPS, EPA-450/3-91-030, July, 
1992.

 Table 1--Industrial Source Categories Affected by This Proposed Action
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                                                   Examples of regulated
        Source category          NAICS Code \a\          entities
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Industrial....................            325312  Phosphoric Acid; and
                                                   Phosphate
                                                   Fertilizers.
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\a\ North American Industry Classification System.


[[Page 66515]]

B. Where can I get a copy of this document and other related 
information?

    In addition to being available in the docket, an electronic copy of 
this action is available on the Internet through the EPA's Technology 
Transfer Network (TTN) Web site, a forum for information and technology 
exchange in various areas of air pollution control. Following signature 
by the EPA Administrator, the EPA will post a copy of this proposed 
action at: https://www.epa.gov/ttn/atw/phosph/phosphpg.html. Following 
publication in the Federal Register, the EPA will post the Federal 
Register version of the proposal and key technical documents at the 
same Web site. Information on the overall residual risk and technology 
review program is available at the following Web site: https://www.epa.gov/ttn/atw/rrisk/rtrpg.html.

C. What should I consider as I prepare my comments for the EPA?

    Submitting CBI. Do not submit information containing CBI to the EPA 
through https://www.regulations.gov or email. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
a disk or CD-ROM that you mail to the EPA, mark the outside of the disk 
or CD-ROM as CBI and then identify electronically within the disk or 
CD-ROM the specific information that is claimed as CBI. In addition to 
one complete version of the comments that includes information claimed 
as CBI, you must submit a copy of the comments that does not contain 
the information claimed as CBI for inclusion in the public docket. If 
you submit a CD-ROM or disk that does not contain CBI, mark the outside 
of the disk or CD-ROM clearly that it does not contain CBI. Information 
not marked as CBI will be included in the public docket and the EPA's 
electronic public docket without prior notice. Information marked as 
CBI will not be disclosed except in accordance with procedures set 
forth in 40 Code of Federal Regulations (CFR) part 2. Send or deliver 
information identified as CBI only to the following address: Roberto 
Morales, OAQPS Document Control Officer (C404-02), OAQPS, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711, Attention Docket ID Number EPA-HQ-OAR-2012-0522.

II. Background

A. What are the statutory authorities for this action?

1. NESHAP Authority
    Section 112 of the CAA establishes a two-stage regulatory process 
to address emissions of hazardous air pollutants (HAPs) from stationary 
sources. In the first stage, after the EPA has identified categories of 
sources emitting one or more of the HAP listed in CAA section 112(b), 
CAA section 112(d) requires us to promulgate technology-based NESHAP 
for those sources. ``Major sources'' are those that emit or have the 
potential to emit 10 tons per year (tpy) or more of a single HAP or 25 
tpy or more of any combination of HAPs. For major sources, the 
technology-based NESHAP must reflect the maximum degree of emission 
reductions of HAPs achievable (after considering cost, energy 
requirements and non-air quality health and environmental impacts) and 
are commonly referred to as maximum achievable control technology 
(MACT) standards.
    MACT standards must reflect the maximum degree of emissions 
reduction achievable through the application of measures, processes, 
methods, systems or techniques, including, but not limited to, measures 
that (1) reduce the volume of or eliminate pollutants through process 
changes, substitution of materials or other modifications; (2) enclose 
systems or processes to eliminate emissions; (3) capture or treat 
pollutants when released from a process, stack, storage or fugitive 
emissions point; (4) are design, equipment, work practice or 
operational standards (including requirements for operator training or 
certification); or (5) are a combination of the above. CAA section 
112(d)(2)(A)-(E). The MACT standards may take the form of design, 
equipment, work practice or operational standards where the EPA first 
determines either that (1) a pollutant cannot be emitted through a 
conveyance designed and constructed to emit or capture the pollutant, 
or that any requirement for, or use of, such a conveyance would be 
inconsistent with law; or (2) the application of measurement 
methodology to a particular class of sources is not practicable due to 
technological and economic limitations. CAA section 112(h)(1)-(2).
    The MACT ``floor'' is the minimum control level allowed for MACT 
standards promulgated under CAA section 112(d)(3) and may not be based 
on cost considerations. For new sources, the MACT floor cannot be less 
stringent than the emissions control that is achieved in practice by 
the best-controlled similar source. The MACT floor for existing sources 
can be less stringent than floors for new sources but not less 
stringent than the average emissions limitation achieved by the best-
performing 12 percent of existing sources in the category or 
subcategory (or the best-performing five sources for categories or 
subcategories with fewer than 30 sources). In developing MACT 
standards, the EPA must also consider control options that are more 
stringent than the floor. We may establish standards more stringent 
than the floor based on considerations of the cost of achieving the 
emission reductions, any non-air quality health and environmental 
impacts and energy requirements.
    The EPA is then required to review these technology-based standards 
and revise them ``as necessary (taking into account developments in 
practices, processes, and control technologies)'' no less frequently 
than every eight years. CAA section 112(d)(6). In conducting this 
review, the EPA is not required to recalculate the MACT floor. NRDC v. 
EPA, 529 F.3d 1077, 1084 (D. C. Cir. 2008). Association of Battery 
Recyclers, Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 2013).
    The second stage in standard-setting focuses on reducing any 
remaining (i.e., ``residual'') risk according to CAA section 112(f). 
CAA section 112(f)(1) required that the EPA prepare a report to 
Congress discussing (among other things) methods of calculating the 
risks posed (or potentially posed) by sources after implementation of 
the MACT standards, the public health significance of those risks and 
the EPA's recommendations as to legislation regarding such remaining 
risk. The EPA prepared and submitted the Residual Risk Report to 
Congress, EPA-453/R-99-001 (Risk Report) in March 1999. CAA section 
112(f)(2) then provides that if Congress does not act on any 
recommendation in the Risk Report, the EPA must analyze and address 
residual risk for each category or subcategory of sources 8 years after 
promulgation of such standards pursuant to CAA section 112(d).
    CAA section 112(f)(2) of the CAA requires the EPA to determine for 
source categories subject to MACT standards whether the emission 
standards provide an ample margin of safety to protect public health. 
CAA section 112(f)(2)(B) of the CAA expressly preserves the EPA's use 
of the two-step process for developing standards to address any 
residual risk and the agency's interpretation of ``ample margin of

[[Page 66516]]

safety'' developed in the National Emissions Standards for Hazardous 
Air Pollutants: Benzene Emissions from Maleic Anhydride Plants, 
Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment 
Leaks, and Coke By-Product Recovery Plants (Benzene NESHAP) (54 FR 
38044, September 14, 1989). The EPA notified Congress in the Risk 
Report that the agency intended to use the Benzene NESHAP approach in 
making CAA section 112(f) residual risk determinations (EPA-453/R-99-
001, p. ES-11). The EPA subsequently adopted this approach in its 
residual risk determinations and in a challenge to the risk review for 
the Synthetic Organic Chemical Manufacturing source category, the 
United States Court of Appeals for the District of Columbia Circuit 
upheld as reasonable the EPA's interpretation that CAA section 
112(f)(2) incorporates the approach established in the Benzene NESHAP. 
See NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008)(``[S]ubsection 
112(f)(2)(B) expressly incorporates the EPA's interpretation of the 
Clean Air Act from the Benzene standard, complete with a citation to 
the Federal Register.''); see also A Legislative History of the Clean 
Air Act Amendments of 1990, vol. 1, p. 877 (Senate debate on Conference 
Report).
    The first step in the process of evaluating residual risk is the 
determination of acceptable risk. If risks are unacceptable, the EPA 
cannot consider cost in identifying the emissions standards necessary 
to bring risks to an acceptable level. The second step is the 
determination of whether standards must be further revised in order to 
provide an ample margin of safety to protect public health. The ample 
margin of safety is the level at which the standards must be set, 
unless an even more stringent standard is necessary to prevent, taking 
into consideration costs, energy, safety and other relevant factors, an 
adverse environmental effect.
a. Step 1-Determination of Acceptability
    The agency in the Benzene NESHAP concluded that ``the acceptability 
of risk under section 112 is best judged on the basis of a broad set of 
health risk measures and information'' and that the ``judgment on 
acceptability cannot be reduced to any single factor.'' Benzene NESHAP 
at 38046. The determination of what represents an ``acceptable'' risk 
is based on a judgment of ``what risks are acceptable in the world in 
which we live'' (Risk Report at 178, quoting NRDC v. EPA, 824 F. 2d 
1146, 1165 (D.C. Cir. 1987) (en banc) (``Vinyl Chloride''), recognizing 
that our world is not risk-free.
    In the Benzene NESHAP, we stated that ``EPA will generally presume 
that if the risk to [the maximum exposed] individual is no higher than 
approximately one in 10 thousand, that risk level is considered 
acceptable.'' 54 FR at 38045, September 14, 1989. We discussed the 
maximum individual lifetime cancer risk (or maximum individual risk 
(MIR)) as being ``the estimated risk that a person living near a plant 
would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years.'' Id. We explained that this measure of 
risk ``is an estimate of the upper bound of risk based on conservative 
assumptions, such as continuous exposure for 24 hours per day for 70 
years.'' Id. We acknowledged that maximum individual lifetime cancer 
risk ``does not necessarily reflect the true risk, but displays a 
conservative risk level which is an upper-bound that is unlikely to be 
exceeded.'' Id.
    Understanding that there are both benefits and limitations to using 
the MIR as a metric for determining acceptability, we acknowledged in 
the Benzene NESHAP that ``consideration of maximum individual risk * * 
* must take into account the strengths and weaknesses of this measure 
of risk.'' Id. Consequently, the presumptive risk level of 100-in-1 
million (1-in-10 thousand) provides a benchmark for judging the 
acceptability of maximum individual lifetime cancer risk, but does not 
constitute a rigid line for making that determination. Further, in the 
Benzene NESHAP, we noted that:

``[p]articular attention will also be accorded to the weight of 
evidence presented in the risk assessment of potential 
carcinogenicity or other health effects of a pollutant. While the 
same numerical risk may be estimated for an exposure to a pollutant 
judged to be a known human carcinogen, and to a pollutant considered 
a possible human carcinogen based on limited animal test data, the 
same weight cannot be accorded to both estimates. In considering the 
potential public health effects of the two pollutants, the Agency's 
judgment on acceptability, including the MIR, will be influenced by 
the greater weight of evidence for the known human carcinogen.''

    Id. at 38046. The agency also explained in the Benzene NESHAP that:

``[i]n establishing a presumption for MIR, rather than a rigid line 
for acceptability, the Agency intends to weigh it with a series of 
other health measures and factors. These include the overall 
incidence of cancer or other serious health effects within the 
exposed population, the numbers of persons exposed within each 
individual lifetime risk range and associated incidence within, 
typically, a 50 km exposure radius around facilities, the science 
policy assumptions and estimation uncertainties associated with the 
risk measures, weight of the scientific evidence for human health 
effects, other quantified or unquantified health effects, effects 
due to co-location of facilities, and co-emission of pollutants.''

Id. at 38045. In some cases, these health measures and factors taken 
together may provide a more realistic description of the magnitude of 
risk in the exposed population than that provided by maximum individual 
lifetime cancer risk alone.

    As noted earlier, in NRDC v. EPA, the court held that CAA section 
112(f)(2) ``incorporates the EPA's interpretation of the Clean Air Act 
from the Benzene Standard.'' The court further held that Congress' 
incorporation of the Benzene standard applies equally to carcinogens 
and non-carcinogens. 529 F.3d at 1081-82. Accordingly, we also consider 
non-cancer risk metrics in our determination of risk acceptability and 
ample margin of safety.
b. Step 2-Determination of Ample Margin of Safety
    CAA section 112(f)(2) requires the EPA to determine, for source 
categories subject to MACT standards, whether those standards provide 
an ample margin of safety to protect public health. As explained in the 
Benzene NESHAP, ``the second step of the inquiry, determining an `ample 
margin of safety,' again includes consideration of all of the health 
factors, and whether to reduce the risks even further. . . . Beyond 
that information, additional factors relating to the appropriate level 
of control will also be considered, including costs and economic 
impacts of controls, technological feasibility, uncertainties and any 
other relevant factors. Considering all of these factors, the agency 
will establish the standard at a level that provides an ample margin of 
safety to protect the public health, as required by section 112.'' 54 
FR at 38046, September 14, 1989.
    According to CAA section 112(f)(2)(A), if the MACT standards for 
HAP ``classified as a known, probable, or possible human carcinogen do 
not reduce lifetime excess cancer risks to the individual most exposed 
to emissions from a source in the category or subcategory to less than 
one in one million,'' the EPA must promulgate residual risk standards 
for the source category (or subcategory), as necessary to provide an 
ample margin of safety to protect public health. In doing so, the EPA 
may adopt standards equal to existing MACT standards if the EPA 
determines that the existing standards

[[Page 66517]]

(i.e., the MACT standards) are sufficiently protective. NRDC v. EPA, 
529 F.3d 1077, 1083 (D.C. Cir. 2008) (``If EPA determines that the 
existing technology-based standards provide an `ample margin of 
safety,' then the Agency is free to readopt those standards during the 
residual risk rulemaking.'') The EPA must also adopt more stringent 
standards, if necessary, to prevent an adverse environmental effect,\2\ 
but must consider cost, energy, safety and other relevant factors in 
doing so.
---------------------------------------------------------------------------

    \2\ ``Adverse environmental effect'' is defined as any 
significant and widespread adverse effect, which may be reasonably 
anticipated to wildlife, aquatic life or natural resources, 
including adverse impacts on populations of endangered or threatened 
species or significant degradation of environmental qualities over 
broad areas. CAA section 112(a)(7).
---------------------------------------------------------------------------

    The CAA does not specifically define the terms ``individual most 
exposed,'' ``acceptable level'' and ``ample margin of safety.'' In the 
Benzene NESHAP, 54 FR at 38044-38045, September 14, 1989, we stated as 
an overall objective:

    In protecting public health with an ample margin of safety under 
section 112, EPA strives to provide maximum feasible protection 
against risks to health from hazardous air pollutants by (1) 
protecting the greatest number of persons possible to an individual 
lifetime risk level no higher than approximately 1-in-1 million and 
(2) limiting to no higher than approximately 1-in-10 thousand [i.e., 
100-in-1 million] the estimated risk that a person living near a 
plant would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years.

    The agency further stated that ``[t]he EPA also considers incidence 
(the number of persons estimated to suffer cancer or other serious 
health effects as a result of exposure to a pollutant) to be an 
important measure of the health risk to the exposed population. 
Incidence measures the extent of health risks to the exposed population 
as a whole, by providing an estimate of the occurrence of cancer or 
other serious health effects in the exposed population.'' Id. at 38045, 
September 14, 1989.
    In the ample margin of safety decision process, the agency again 
considers all of the health risks and other health information 
considered in the first step, including the incremental risk reduction 
associated with standards more stringent than the MACT standard or a 
more stringent standard that EPA has determined is necessary to ensure 
risk is acceptable. In the ample margin of safety analysis, the agency 
considers additional factors, including costs and economic impacts of 
controls, technological feasibility, uncertainties and any other 
relevant factors. Considering all of these factors, the agency will 
establish the standard at a level that provides an ample margin of 
safety to protect the public health, as required by CAA section 112(f). 
54 FR 38046, September 14, 1989.
2. NSPS Authority
    New source performance standards implement CAA section 111, which 
requires that each NSPS reflect the degree of emission limitation 
achievable through the application of the best system of emission 
reduction (BSER) which (taking into consideration the cost of achieving 
such emission reductions, any nonair quality health and environmental 
impact and energy requirements) the Administrator determines has been 
adequately demonstrated.
    Existing affected facilities that are modified or reconstructed are 
also be subject to NSPS. Under CAA section 111(a)(4), ``modification'' 
means any physical change in, or change in the method of operation of, 
a stationary source which increases the amount of any air pollutant 
emitted by such source or which results in the emission of any air 
pollutant not previously emitted. Changes to an existing facility that 
do not result in an increase in emissions are not considered 
modifications.
    Rebuilt emission units would become subject to the NSPS under the 
reconstruction provisions in 40 CFR 60.15, regardless of changes in 
emission rate. Reconstruction means the replacement of components of an 
existing facility such that: (1) The fixed capital cost of the new 
components exceeds 50 percent of the fixed capital cost that would be 
required to construct a comparable entirely new facility; and (2) it is 
technologically and economically feasible to meet the applicable 
standards (40 CFR 60.15).
    Section 111(b)(1)(B) of the CAA requires the EPA to periodically 
review and, if appropriate, revise the standards of performance as 
necessary to reflect improvements in methods for reducing emissions. 
The EPA need not review an NSPS if the agency determines that such 
review is not appropriate in light of readily available information on 
the efficacy of the standard. When conducting the review under CAA 
section 111(b)(1)(B), the EPA considers both (1) whether developments 
in technology or other factors support the conclusion that a different 
system of emissions reduction has become the ``best system of emissions 
reduction'' and (2) whether emissions limitations and percent 
reductions beyond those required by the current standards are achieved 
in practice.

B. What are the source categories and how do the current NESHAP and 
NSPS regulate emissions?

1. Description of Phosphoric Acid Manufacturing Source Category
    In 2014, 12 facilities in the United States manufacture phosphoric 
acid. The basic step for producing phosphoric acid is acidulation of 
phosphate rock. Typically, sulfuric acid, phosphate rock and water are 
combined together and allowed to react to produce phosphoric acid and 
gypsum. When phosphate rock is acidulated to manufacture WPPA, fluorine 
contained in the rock is released. Fluoride (F) compounds, 
predominately HF, are produced as particulates and gases that are 
emitted to the atmosphere unless removed from the exhaust stream. Some 
of these same F compounds also remain in the product acid and are 
released as air pollutants during subsequent processing of the acid. 
Gypsum is pumped as a slurry to ponds atop stacks of waste gypsum where 
the liquids separate from the slurry and are decanted for return to the 
process. The gypsum, which is discarded on the stack, is a solid waste 
stream produced in this process. Five facilities concentrate WPPA to 
make SPA, typically using the vacuum evaporation process. While one 
manufacturer is permitted to use a submerged combustion process for the 
production of SPA, that process was indefinitely shutdown on June 1, 
2006. The majority of WPPA is used to produce phosphate fertilizers.
    Additional processes may also be used to further refine phosphoric 
acid. At least two facilities have a defluorination process to remove F 
from the phosphoric acid product, and one company uses a solvent 
extraction process to remove metals and organics and to further refine 
WPPA into purified phosphoric acid (PPA) for use in food manufacturing 
or specialized chemical processes. In addition, four facilities have 
processes to remove organics from the acid (i.e., the green acid 
process).
    Sources of HF emissions from phosphoric acid plants include gypsum 
dewatering stacks, cooling ponds, cooling towers, calciners, reactors, 
filters, evaporators and other process equipment.
2. Federal Emission Standards Applicable to the Phosphoric Acid 
Manufacturing Source Category
    The following federal emission standards are associated with the 
Phosphoric Acid Manufacturing source category and are subject of this 
proposed rulemaking:

[[Page 66518]]

     National Emission Standards for Hazardous Air Pollutants 
from Phosphoric Acid Manufacturing Plants (40 CFR part 63, subpart AA);
     Standards of Performance for the Phosphate Fertilizer 
Industry: Wet-Process Phosphoric Acid Plants (40 CFR part 60, subpart 
T); and
     Standards of Performance for the Phosphate Fertilizer 
Industry: Superphosphoric Acid Plants (40 CFR part 60, subpart U).
a. Phosphoric Acid Manufacturing NESHAP Emission Regulations
    The EPA promulgated 40 CFR part 63, subpart AA for the Phosphoric 
Acid Manufacturing source category on June 10, 1999 (64 FR 31358). The 
NESHAP established standards for major sources to control HAP emissions 
from phosphoric acid facilities. Total F emission limits, as a 
surrogate for the HAP HF, were set for WPPA process lines and SPA 
process lines. For new sources, WPPA process lines are limited to 
0.0135 pounds (lb) total F per ton (lb total F/ton) of equivalent 
phosphorus pentoxide (P2O5), and SPA process 
lines are limited to 0.00870 lb total F/ton of equivalent 
P2O5. For existing sources, WPPA process lines 
are limited to 0.020 lb total F/ton of equivalent 
P2O5, SPA process lines using a vacuum 
evaporation process are limited to 0.010 lb total F/ton of equivalent 
P2O5, and SPA process lines using a submerged 
combustion process are limited to 0.020 lb total F/ton of equivalent 
P2O5.
    The NESHAP established emission limits for PM from phosphate rock 
dryers and phosphate rock calciners as a surrogate for metal HAP. For 
new sources, phosphate rock dryers are limited to 0.060 pounds PM per 
ton (lb PM/ton) of phosphate rock feed, and phosphate rock calciners 
are limited to 0.040 grains of PM per dry standard cubic feet (gr/
dscf). For existing sources, phosphate rock dryers are limited to 
0.2150 lb PM/ton of phosphate rock feed, and phosphate rock calciners 
are limited to 0.080 gr/dscf.
    Also, the NESHAP established an emission limit for methyl isobutyl 
ketone (MIBK) for PPA process lines and work practices for cooling 
towers. For new and existing sources, each product acid stream from PPA 
process lines is limited to 20 parts per million (ppm) of MIBK, and 
each raffinate stream from PPA process lines is limited to 30 ppm of 
MIBK (compliance is based on a 30-day average of daily concentration 
measurements).
b. Phosphoric Acid Manufacturing NSPS Emission Regulations
    The EPA promulgated 40 CFR part 60, subpart T for Wet-Process 
Phosphoric Acid Plants on August 6, 1975 (40 FR 33154). The NSPS 
established standards to control total F emissions from WPPA plants, 
including reactors, filters, evaporators and hot wells. For new, 
modified, and reconstructed sources WPPA plants are limited to 0.020 lb 
total F/ton of equivalent P2O5.
    The EPA promulgated 40 CFR part 60, subpart U for Superphosphoric 
Acid Plants on August 6, 1975 (40 FR 33155). The NSPS established 
standards to control total F emissions from SPA plants, including 
evaporators, hot wells, acid sumps and cooling tanks. For new, modified 
and reconstructed sources, SPA plants are limited to 0.010 lb total F/
ton of equivalent P2O5.
3. Description of Phosphate Fertilizer Production Source Category
    In 2014, there are 11 operating facilities that produce phosphate 
fertilizers, and most facilities can produce either MAP or DAP in the 
same process train. However, approximately 80 percent of all ammonium 
phosphates are produced as MAP. MAP and DAP plants are generally 
collocated with WPPA plants since it is manufactured from phosphoric 
acid and ammonia. The MAP and DAP manufacturing process consists of 
three basic steps: Reaction, granulation and finishing operations such 
as drying, cooling and screening. In addition, some of the fluorine is 
liberated as HF and silicon tetrafluoride (SiF4), with the 
majority being emitted as HF. Sources of F emissions from MAP and DAP 
plants include the reactor, granulator, dryer, cooler, screens and 
mills.
    TSP is made as run-of-the-pile-TSP (ROP-TSP) and granular TSP 
(GTSP) by reacting WPPA with ground phosphate rock. The phosphoric acid 
used in the GTSP process is appreciably lower in concentration (40- 
percent P2O5) than that used to manufacture ROP-
TSP product (50- to 55- percent P2O5). The GTSP 
process yields larger, more uniform particles with improved storage and 
handling properties than the ROP-TSP process. Currently, no facilities 
produce ROP-TSP or GTSP,\3\ although one facility retains an operating 
permit to store GTSP.
---------------------------------------------------------------------------

    \3\ According to 2014 production and trade statistics issued by 
International Fertilizer Industry Association (IFA).
---------------------------------------------------------------------------

4. Federal Emission Standards Applicable to the Phosphate Fertilizer 
Production Source Category
    The following federal emission standards are associated with the 
Phosphate Fertilizer Production source category and are subject of this 
proposed rulemaking:
     National Emission Standards for Hazardous Air Pollutants 
from Phosphate Fertilizers Production Plants (40 CFR part 63, subpart 
BB);
     Standards of Performance for the Phosphate Fertilizer 
Industry: Diammonium Phosphate Plants (40 CFR part 60, subpart V);
     Standards of Performance for the Phosphate Fertilizer 
Industry: Triple Superphosphate Plants (40 CFR part 60, subpart W); and
     Standards of Performance for the Phosphate Fertilizer 
Industry: Granular Triple Superphosphate Storage Facilities (40 CFR 
part 60, subpart X).
a. Phosphate Fertilizer Production NESHAP Emission Regulations
    The EPA promulgated 40 CFR part 63, subpart BB for the Phosphate 
Fertilizer Production source category on June 10, 1999 (64 FR 31358). 
The NESHAP established standards for major sources to control HAP 
emissions from phosphate fertilizer facilities. As a surrogate for HF, 
the NESHAP set total F emission limits for DAP and/or MAP process lines 
and GTSP process lines and storage buildings. The NESHAP also 
established work practices for GTSP production. For new sources, DAP 
and MAP process lines are limited to 0.058 lb total F/ton of equivalent 
P2O5 feed. For existing sources, DAP and MAP 
process lines are limited to 0.06 lb total F/ton of equivalent 
P2O5 feed. For new sources, GTSP process lines 
are limited to 0.1230 lb total F/ton of equivalent 
P2O5 feed. For existing sources, GTSP process 
lines are limited to 0.150 lb total F/ton of equivalent 
P2O5 feed. For new and existing sources, GTSP 
storage buildings are limited to 5.0x10-4 pounds of total F 
per hour per ton of equivalent P2O5 stored.
b. Phosphate Fertilizer Production NSPS Emission Regulations
    The EPA promulgated 40 CFR part 60, subpart V for Diammonium 
Phosphate Plants on July 25, 1977 (42 FR 37938). The NSPS established 
standards to control total F emissions from granular DAP plants, 
including reactors, granulators, dryers, coolers, screens and mills. 
For new, modified and reconstructed sources, granular DAP plants are 
limited to 0.06 lb total F/ton of equivalent P2O5 
feed.

[[Page 66519]]

    The EPA promulgated 40 CFR part 60, subpart W for Triple 
Superphosphate Plants on July 25, 1977 (42 FR 37938). The NSPS 
established standards to control total F emissions from the production 
of ROP-TSP and GTSP, and the storage of ROP-TSP. For new, modified and 
reconstructed sources, production of ROP-TSP and GTSP and the storage 
of ROP-TSP is limited to 0.20 lb total F/ton of equivalent 
P2O5 feed.
    The EPA promulgated 40 CFR part 60, subpart X for Granular Triple 
Superphosphate Storage Facilities on July 25, 1977 (42 FR 37938). The 
NSPS established standards to control total F emissions from the 
storage of GTSP, including storage or curing buildings (noted as 
``piles'' in subpart X), conveyors, elevators, screens and mills. For 
new, modified and reconstructed sources, the storage of GTSP is limited 
to 5.0x10-4 pounds of total F per hour per ton of equivalent 
P2O5 stored.
C. What data collection activities were conducted to support this 
action?
    In April 2010, the EPA requested data, pursuant to CAA section 114, 
from the seven companies that own and operate the 12 Phosphoric Acid 
facilities and 11 Phosphate Fertilizer facilities. The EPA requested 
available information regarding process equipment, control devices, 
point and fugitive emissions, and other aspects of facility operations. 
The seven companies completed the surveys for their facilities and 
submitted the responses to the EPA in the fall of 2010. Additionally, 
the EPA requested that the facilities conduct emissions tests in 2010 
for certain HAP from specific processes. Pollutants tested included HF, 
total F, PM and HAP metals. The facilities also conducted analyses of 
the phosphate rock used in the manufacture of phosphoric acid. The 
facilities submitted the results of these tests to the EPA in the fall 
of 2010. The test results are available in the docket for this action.
    On January 24, 2014, the EPA issued another CAA section 114 survey 
and testing request to certain facilities in order to gather additional 
mercury (Hg) and HF emissions data from calciner operations, and 
additional total F and HF emissions data from certain WPPA, SPA and APF 
lines. The selection of WPPA, SPA and APF lines to be tested was based 
on a review of the data received from the April 13, 2010 CAA section 
114 survey request. In addition to the testing, the EPA requested 
process production rate data concurrent with the duration of the 
emissions testing (e.g., phosphoric acid production in tons per hour of 
P2O5).
    For more information regarding the April 2010 CAA section 114 and 
January 2014 CAA section 114 requests, refer to the memorandum, 
``Information Collection and Additional Data Received for the 
Phosphoric Acid and Phosphate Fertilizer Production Source 
Categories,'' which is available in the docket for this action.
D. What other relevant background information and data are available?
    To support this proposed rulemaking, the EPA used information from 
the EPA's National Emissions Inventory (NEI), and the RACT/BACT/LAER 
Clearinghouse (RBLC) when performing the technology review and other 
analyses. If emissions for a specific emission point were available in 
the NEI, but test data were not available, we used the NEI data to 
estimate emissions. This approach was primarily applicable to 
combustion emissions. The EPA utilized the RBLC as a reference for 
additional control technologies when performing the technology review. 
See sections III.C, and IV.D, and V.C of this preamble for further 
details on the use of these sources of information.
    Table 2 of this preamble summarizes the emissions data collected 
for point sources and fugitive sources at phosphoric acid manufacturing 
and phosphate fertilizer production facilities of HF, Total PM, Hg and 
other HAP Metals. This includes emissions data from stack tests, 
fugitive emission reports, and the NEI.

     Table 2--Summary of Emissions Data Collected for Point Sources and Fugitive Sources at Phosphoric Acid
                          Manufacturing and Phosphate Fertilizer Production Facilities
----------------------------------------------------------------------------------------------------------------
                                                                     Total PM                       HAP Metals
     Source category and emission point type         HF  (tpy)         (tpy)         Hg  (tpy)       (tpy) \a\
----------------------------------------------------------------------------------------------------------------
Phosphoric Acid Manufacturing:
    Point Sources...............................              38             162           0.019            1.07
    Fugitive Sources............................           2,155               0               0               0
    Total.......................................           2,193             162           0.019            1.07
Phosphate Fertilizer Production:
    Point Sources...............................            85.0             907            0.13            0.40
    Fugitive Sources............................          0.0051               0               0               0
    Total.......................................            85.0             907            0.13            0.40
----------------------------------------------------------------------------------------------------------------
\a\ HAP metals includes: antimony, arsenic, beryllium, cadmium, chromium (VI), chromium III, cobalt, lead,
  manganese, nickel, and selenium.

III. Analytical Procedures

    In this section, we describe the analyses performed to support the 
proposed decisions for the RTR and other issues addressed in this 
proposal.

A. How did we estimate post-MACT risks posed by the source categories?

    The EPA conducted a risk assessment that provides estimates of the 
MIR posed by the HAP emissions from each source in the source category, 
the hazard index (HI) for chronic exposures to HAP with the potential 
to cause non-cancer health effects, and the hazard quotient (HQ) for 
acute exposures to HAP with the potential to cause non-cancer health 
effects. The assessment also provides estimates of the distribution of 
cancer risks within the exposed populations, cancer incidence and an 
evaluation of the potential for adverse environmental effects. The risk 
assessment consisted of seven primary steps, as discussed below. The 
docket for this rulemaking contains the following document, which 
provides more information on the risk assessment inputs and models: 
Draft Residual Risk Assessment for Phosphate Fertilizer Production and 
Phosphoric Acid Manufacturing. The methods used to assess risks (as 
described in the seven primary steps below) are consistent with those 
peer-reviewed by a panel of the EPA's Science Advisory Board (SAB) in 
2009 and described in their peer review report issued in 2010; \4\ they 
are also consistent with the key

[[Page 66520]]

recommendations contained in that report.
---------------------------------------------------------------------------

    \4\ U.S. EPA SAB. Risk and Technology Review (RTR) Risk 
Assessment Methodologies: For Review by the EPA's Science Advisory 
Board with Case Studies--MACT I Petroleum Refining Sources and 
Portland Cement Manufacturing, May 2010.
---------------------------------------------------------------------------

1. How did we estimate actual emissions and identify the emissions 
release characteristics?
a. Estimation of Actual Emissions
    Data from our April 2010 CAA section 114 request were used for this 
assessment. The EPA performed a review and thorough quality assurance/
quality control (QA/QC) of the data to identify any limitations and 
issues. The EPA also contacted facility and industry representatives to 
clarify details and resolve issues with their data submissions.
    The EPA updated the 2005 NEI data for the Phosphate Fertilizer 
Production and Phosphoric Acid Manufacturing source categories with the 
emissions data and corrections to facility and emission point locations 
that we received from industry through the CAA section 114 request. The 
data incorporation procedures are discussed in the memorandum, 
``Emissions Data Used in Residual Risk Modeling: Phosphoric Acid and 
Phosphate Fertilizer Production Source Categories,'' which is available 
in the docket for this action. In a few limited instances, test data 
were not available for an emission point available in the NEI, in which 
case the existing emissions data in the 2005 NEI were used. The 
following sections of this preamble describe each of the source 
categories, including a discussion of the applicable information 
sources used to estimate emissions.
b. Phosphoric Acid Manufacturing
    Phosphate rock is the starting material for the production of all 
phosphate products. Once the rock reaches the phosphoric acid 
production facility, phosphoric acid is typically produced using the 
wet method, in which beneficiated ground phosphate rock (i.e., 
phosphate rock that has been processed to remove impurities) is reacted 
with sulfuric acid and weak phosphoric acid to produce phosphoric acid 
and phosphogypsum, a waste product. The phosphogypsum is disposed of on 
site in waste piles known as gypsum dewatering stacks (which are also 
referred to as ``gypsum stacks'' or ``gypstacks''). Phosphoric acid 
facility emissions are both point sources and fugitive sources. Point 
source emissions originate from equipment (e.g., reactors, filters, 
evaporators and calciners) associated with phosphoric acid 
manufacturing processes including WPPA process lines, SPA process lines 
and PPA process lines. Fugitive emissions are released from cooling 
ponds, cooling towers and gypsum dewatering stacks.
    In 2014, there are 12 phosphoric acid manufacturing facilities 
operating in the United States. Based on the emissions dataset (see the 
memorandum, ``Emissions Data Used in Residual Risk Modeling: Phosphoric 
Acid and Phosphate Fertilizer Production Source Categories,'' which is 
available in the docket for this action), all 12 of these facilities 
are, or show the potential to be, major sources of HAP even though two 
of these facilities identified themselves as area sources of HAP in 
their response to our April 2010 CAA section 114 request. Ten of these 
12 facilities are collocated with phosphate fertilizer production 
facilities.
    Based on the emissions data provided with the CAA section 114 
request or available in the NEI, the total HAP emissions for the 
Phosphoric Acid Manufacturing source category are approximately 2,230 
tpy. HF is the HAP emitted in the largest quantity across these 12 
facilities, accounting for approximately 98 percent of the total HAP 
emissions by mass. Persistent and bioaccumulative HAP (PB-HAP) 
emissions reported from these facilities include Hg, Pb, dioxin, 
polycyclic organic matter (POM) and cadmium compounds.
c. Phosphate Fertilizer Production
    Phosphate fertilizer operations are generally collocated with 
phosphoric acid manufacturing facilities, which provide the feedstock 
(phosphoric acid) for phosphate fertilizer production facilities. 
Phosphate fertilizer is produced by reacting phosphoric acid and 
ammonia, followed by granulation, drying, cooling and screening. 
Emissions from each of these steps are included in the estimated point 
source emissions for each facility. Phosphate fertilizer facilities 
also send water to cooling ponds and, thus, contribute to the fugitive 
emissions from these sources. However, the contribution from phosphate 
fertilizer production sources to the fugitive emissions from the 
cooling ponds is minimal. Therefore, we have assigned fugitive 
emissions from cooling ponds to the Phosphoric Acid Manufacturing 
source category.
    In 2014, there are 11 phosphate fertilizer production facilities 
operating in the United States. Based on the emissions dataset (see the 
memorandum, ``Emissions Data Used in Residual Risk Modeling: Phosphoric 
Acid and Phosphate Fertilizer Production Source Categories,'' which is 
available in the docket for this action), all 11 of these facilities 
are, or show the potential to be, major sources of HAP even though one 
of these facilities identified itself as an area source of HAP in their 
response to our April 2010 CAA section 114 request. Ten of these 11 
facilities are collocated with phosphoric acid manufacturing 
facilities.
    Based on the emissions data provided with the CAA section 114 
request or available in the NEI, the total HAP emissions for the 
Phosphate Fertilizer Production source category are approximately 86 
tpy. The HAP emitted in the largest quantity across these 11 facilities 
is HF. HF accounts for 99 percent of the total emissions by mass. PB-
HAP emissions reported from these facilities include Hg, Pb, and 
cadmium compounds.
2. How did we estimate MACT-allowable emissions?
    The available emissions data in the RTR emissions dataset include 
estimates of the mass of HAP emitted during the specified annual time 
period. In some cases, these ``actual'' emission levels are lower than 
the emission levels required to comply with the MACT standards. The 
emissions level allowed to be emitted by the MACT standards is referred 
to as the ``MACT-allowable'' emissions level. We discussed the use of 
both MACT-allowable and actual emissions in the final Coke Oven 
Batteries residual risk rule (70 FR 19998-19999, April 15, 2005) and in 
the proposed and final Hazardous Organic NESHAP residual risk rules (71 
FR 34428, June 14, 2006, and 71 FR 76609, December 21, 2006, 
respectively). In those previous actions, we noted that assessing the 
risks at the MACT-allowable level is inherently reasonable since these 
risks reflect the maximum level facilities could emit and still comply 
with national emission standards. We also explained that it is 
reasonable to consider actual emissions, where such data are available, 
in both steps of the risk analysis, in accordance with the Benzene 
NESHAP approach. (54 FR 38044, September 14, 1989.) Details on the 
methodologies for calculating allowable emissions, as discussed below, 
are provided in the memorandum, ``Emissions Data Used in Residual Risk 
Modeling: Phosphoric Acid and Phosphate Fertilizer Production Source 
Categories,'' which is available in the docket for this action.
a. Phosphoric Acid Manufacturing
    In the case of this particular source category, point sources 
contribute only a small percentage of overall emissions. Therefore, as 
a conservative approach, we used the emission limits and the

[[Page 66521]]

permitted production capacity specified in the title V permit for each 
facility to calculate allowable emissions for point sources. Because 
emission limits are in terms of total F (pounds of total F per ton of 
P2O5 production), and not the HAP HF, emissions 
for total F were used as a surrogate for HF when calculating allowable 
emissions. If emissions limits were not available in the title V 
permit, we used the emission limits for existing sources in the current 
NESHAP subpart AA. Because emissions limits for metals and MIBK are not 
listed in the permits, we calculated allowable emissions using the 
emissions as measured in the stack tests for the CAA section 114 
request, and scaled these emissions up using the permitted capacity. 
Allowable point source emissions are as much as 59 times higher than 
actual total F emissions, about 8 times higher than actual metal 
emissions, and about 2 times higher than actual MIBK emissions at 
phosphoric acid manufacturing processes.
    For fugitive emissions of HF from gypsum dewatering stacks, cooling 
ponds and cooling towers, the EPA estimated that actual emissions were 
equivalent to allowable emissions. We do not expect fugitive emissions 
to increase from these sources with an increase in production rate, or 
increase significantly during a process upset, as emissions from these 
large fugitive sources are the cumulative result of many decades of 
stacking gypsum waste product and re-circulating cooling water. Because 
of their general homeostatic nature, we expect only minor changes in 
cooling pond emissions over time. We also anticipate that emissions are 
higher during daylight hours and warmer months due to the increased 
evaporation rate associated with higher ambient temperatures. Test data 
for these sources were obtained during the spring and summer seasons 
and during daylight hours. Therefore, emissions would not be expected 
to increase significantly beyond the levels measured during the tests. 
We expect that the emission factors and range of estimates (high, 
medium and low) that we developed, based on the test data for the 
spring and summer seasons obtained from industry, account sufficiently 
for any changes to emissions as ambient conditions change. For more 
information on the development of emission factors, see the memorandum, 
``Emissions Data Used in Residual Risk Modeling: Phosphoric Acid and 
Phosphate Fertilizer Production Source Categories,'' which is available 
in the docket for this action.
b. Phosphate Fertilizer Production
    Similar to phosphoric acid manufacturing, point sources contribute 
only a small percentage of overall emissions from this particular 
source category. Therefore, as a conservative approach, we used the 
emission limits (expressed in pounds of total F per ton of 
P2O5 production) and the permitted production 
capacity specified in the title V permit for each facility to calculate 
point source allowable emissions for total F, as a surrogate for HF. If 
emissions limits were not available in the title V permit, we used the 
limits for existing sources in the current NESHAP subpart BB. Because 
emissions limits for metals are not listed in the permits, we 
calculated allowable emissions using the emissions test data collected 
by the CAA section 114 request, and scaled these emissions up using the 
permitted capacity. Allowable point source emissions are as much as 11 
times higher than actual total F emissions and about 2 times higher 
than actual metal at phosphate fertilizer production processes.
3. How did we conduct dispersion modeling, determine inhalation 
exposures and estimate individual and population inhalation risks?
    Both long-term and short-term inhalation exposure concentrations 
and health risks from the source category addressed in this proposal 
were estimated using the Human Exposure Model (Community and Sector 
HEM-3 version 1.1.0). The HEM-3 performs three primary risk assessment 
activities: (1) Conducting dispersion modeling to estimate the 
concentrations of HAP in ambient air, (2) estimating long-term and 
short-term inhalation exposures to individuals residing within 50 
kilometers (km) of the modeled sources,\5\ and (3) estimating 
individual and population-level inhalation risks using the exposure 
estimates and quantitative dose-response information.
---------------------------------------------------------------------------

    \5\ This metric comes from the Benzene NESHAP. See 54 FR 38046.
---------------------------------------------------------------------------

    The air dispersion model used by the HEM-3 model (AERMOD) is one of 
the EPA's preferred models for assessing pollutant concentrations from 
industrial facilities.\6\ To perform the dispersion modeling and to 
develop the preliminary risk estimates, HEM-3 draws on three data 
libraries. The first is a library of meteorological data, which is used 
for dispersion calculations. This library includes 1 year (2011) of 
hourly surface and upper air observations for more than 800 
meteorological stations, selected to provide coverage of the United 
States and Puerto Rico. A second library of United States Census Bureau 
census block \7\ internal point locations and populations provides the 
basis of human exposure calculations (U.S. Census, 2010). In addition, 
for each census block, the census library includes the elevation and 
controlling hill height, which are also used in dispersion 
calculations. A third library of pollutant unit risk factors and other 
health benchmarks is used to estimate health risks. These risk factors 
and health benchmarks are the latest values recommended by the EPA for 
HAP and other toxic air pollutants. These values are available at: 
https://www.epa.gov/ttn/atw/toxsource/summary.html and are discussed in 
more detail later in this section.
---------------------------------------------------------------------------

    \6\ U.S. EPA. Revision to the Guideline on Air Quality Models: 
Adoption of a Preferred General Purpose (Flat and Complex Terrain) 
Dispersion Model and Other Revisions (70 FR 68218, November 9, 
2005).
    \7\ A census block is the smallest geographic area for which 
census statistics are tabulated.
---------------------------------------------------------------------------

    In developing the risk assessment for chronic exposures, we used 
the estimated annual average ambient air concentrations of each HAP 
emitted by each source for which we have emissions data in the source 
category. The air concentrations at each nearby census block centroid 
were used as a surrogate for the chronic inhalation exposure 
concentration for all the people who reside in that census block. We 
calculated the MIR for each facility as the cancer risk associated with 
a continuous lifetime (24 hours per day, 7 days per week and 52 weeks 
per year for a 70-year period) exposure to the maximum concentration at 
the centroid of inhabited census blocks. Individual cancer risks were 
calculated by multiplying the estimated lifetime exposure to the 
ambient concentration of each of the HAP (in micrograms per cubic meter 
([mu]g/m\3\)) by its unit risk estimate (URE). The URE is an upper 
bound estimate of an individual's probability of contracting cancer 
over a lifetime of exposure to a concentration of 1 microgram of the 
pollutant per cubic meter of air. For residual risk assessments, we 
generally use URE values from the EPA's Integrated Risk Information 
System (IRIS). For carcinogenic pollutants without EPA IRIS values, we 
look to other reputable sources of cancer dose-response values, often 
using California EPA (CalEPA) URE values, where available. In cases 
where new, scientifically credible dose response values have been 
developed in a manner consistent with the EPA guidelines and have 
undergone a peer review process similar to that used by

[[Page 66522]]

the EPA, we may use such dose-response values in place of, or in 
addition to, other values, if appropriate.
    The EPA estimated incremental individual lifetime cancer risks 
associated with emissions from the facilities in the source category as 
the sum of the risks for each of the carcinogenic HAP (including those 
classified as carcinogenic to humans, likely to be carcinogenic to 
humans, and suggestive evidence of carcinogenic potential \8\) emitted 
by the modeled sources. Cancer incidence and the distribution of 
individual cancer risks for the population within 50 km of the sources 
were also estimated for the source category as part of this assessment 
by summing individual risks. A distance of 50 km is consistent with 
both the analysis supporting the 1989 Benzene NESHAP (54 FR 38044, 
September 14, 1989) and the limitations of Gaussian dispersion models, 
including AERMOD.
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    \8\ These classifications also coincide with the terms ``known 
carcinogen, probable carcinogen, and possible carcinogen,'' 
respectively, which are the terms advocated in the EPA's previous 
Guidelines for Carcinogen Risk Assessment, published in 1986 (51 FR 
33992, September 24, 1986). Summing the risks of these individual 
compounds to obtain the cumulative cancer risks is an approach that 
was recommended by the EPA's SAB in their 2002 peer review of EPA's 
National Air Toxics Assessment (NATA) entitled, NATA--Evaluating the 
National-scale Air Toxics Assessment 1996 Data--an SAB Advisory, 
available at: https://yosemite.epa.gov/sab/sabproduct.nsf/
214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf.
---------------------------------------------------------------------------

    To assess the risk of non-cancer health effects from chronic 
exposures, we summed the HQ for each of the HAP that affects a common 
target organ system to obtain the HI for that target organ system (or 
target organ-specific HI, TOSHI). The HQ is the estimated exposure 
divided by the chronic reference value, which is either the EPA 
reference concentration (RfC) (https://www.epa.gov/riskassessment/glossary.htm), defined as ``an estimate (with uncertainty spanning 
perhaps an order of magnitude) of a continuous inhalation exposure to 
the human population (including sensitive subgroups) that is likely to 
be without an appreciable risk of deleterious effects during a 
lifetime,'' or, in cases where an RfC from the EPA's IRIS database is 
not available, a value from the following prioritized sources: (1) The 
Agency for Toxic Substances and Disease Registry Minimum Risk Level 
(https://www.atsdr.cdc.gov/mrls/index.asp), which is defined as ``an 
estimate of daily human exposure to a hazardous substance that is 
likely to be without an appreciable risk of adverse non-cancer health 
effects (other than cancer) over a specified duration of exposure''; 
(2) the CalEPA Chronic Reference Exposure Level (REL) (https://www.oehha.ca.gov/air/hot_spots/pdf/HRAguidefinal.pdf), which is defined 
as ``the concentration level (that is expressed in units of micrograms 
per cubic meter ([mu]g/m\3\) for inhalation exposure and in a dose 
expressed in units of milligram per kilogram-day (mg/kg-day) for oral 
exposures), at or below which no adverse health effects are anticipated 
for a specified exposure duration''; or (3), as noted above, a 
scientifically credible dose-response value that has been developed in 
a manner consistent with the EPA guidelines and has undergone a peer 
review process similar to that used by the EPA, in place of or in 
concert with other values.
    The EPA also evaluated screening estimates of acute exposures and 
risks for each of the HAP at the point of highest potential off-site 
exposure for each facility. To do this, the EPA estimated the risks 
when both the peak hourly emissions rate and worst-case dispersion 
conditions occur. We also assume that a person is located at the point 
of highest impact during that same time. In accordance with our mandate 
in section 112 of the CAA, we use the point of highest off-site 
exposure to assess the potential risk to the maximally exposed 
individual. The acute HQ is the estimated acute exposure divided by the 
acute dose-response value. In each case, the EPA calculated acute HQ 
values using best available, short-term dose-response values. These 
acute dose-response values, which are described below, include the 
acute REL, acute exposure guideline levels (AEGL) and emergency 
response planning guidelines (ERPG) for 1-hour exposure durations. As 
discussed below, we used conservative assumptions for emissions rates, 
meteorology and exposure location for our acute analysis.
    As described in the CalEPA's Air Toxics Hot Spots Program Risk 
Assessment Guidelines, Part I, The Determination of Acute Reference 
Exposure Levels for Airborne Toxicants, an acute REL value (https://www.oehha.ca.gov/air/pdf/acuterel.pdf) is defined as ``the 
concentration level at or below which no adverse health effects are 
anticipated for a specified exposure duration.'' Id. at page 2. Acute 
REL values are based on the most sensitive, relevant, adverse health 
effect reported in the peer-reviewed medical and toxicological 
literature. Acute REL values are designed to protect the most sensitive 
individuals in the population through the inclusion of margins of 
safety. Because margins of safety are incorporated to address data gaps 
and uncertainties, exceeding the REL does not automatically indicate an 
adverse health impact.
    AEGL values were derived in response to recommendations from the 
National Research Council (NRC). As described in Standing Operating 
Procedures (SOP) of the National Advisory Committee on Acute Exposure 
Guideline Levels for Hazardous Substances (https://www.epa.gov/oppt/aegl/pubs/sop.pdf),\9\ ``the NRC's previous name for acute exposure 
levels--community emergency exposure levels--was replaced by the term 
AEGL to reflect the broad application of these values to planning, 
response, and prevention in the community, the workplace, 
transportation, the military, and the remediation of Superfund sites.'' 
Id. at 2.
---------------------------------------------------------------------------

    \9\ National Academy of Sciences (NAS), 2001. Standing Operating 
Procedures for Developing Acute Exposure Levels for Hazardous 
Chemicals, page 2.
---------------------------------------------------------------------------

    This document also states that AEGL values ``represent threshold 
exposure limits for the general public and are applicable to emergency 
exposures ranging from 10 minutes to eight hours.'' Id. at 2. The 
document lays out the purpose and objectives of AEGL by stating that 
``the primary purpose of the AEGL program and the National Advisory 
Committee for Acute Exposure Guideline Levels for Hazardous Substances 
is to develop guideline levels for once-in-a-lifetime, short-term 
exposures to airborne concentrations of acutely toxic, high-priority 
chemicals.'' Id. at 21. In detailing the intended application of AEGL 
values, the document states that ``[i]t is anticipated that the AEGL 
values will be used for regulatory and nonregulatory purposes by U.S. 
federal and state agencies and possibly the international community in 
conjunction with chemical emergency response, planning, and prevention 
programs. More specifically, the AEGL values will be used for 
conducting various risk assessments to aid in the development of 
emergency preparedness and prevention plans, as well as real-time 
emergency response actions, for accidental chemical releases at fixed 
facilities and from transport carriers.'' Id. at 31.
    The AEGL-1 value is then specifically defined as ``the airborne 
concentration (expressed as ppm (parts per million) or mg/m\3\ 
(milligrams per cubic meter)) of a substance above which it is 
predicted that the general population, including susceptible 
individuals, could experience notable discomfort, irritation, or 
certain asymptomatic

[[Page 66523]]

nonsensory effects. However, the effects are not disabling and are 
transient and reversible upon cessation of exposure.'' Id. at 3. The 
document also notes that, ``Airborne concentrations below AEGL-1 
represent exposure levels that can produce mild and progressively 
increasing but transient and nondisabling odor, taste, and sensory 
irritation or certain asymptomatic, nonsensory effects.'' Id. 
Similarly, the document defines AEGL-2 values as ``the airborne 
concentration (expressed as parts per million or milligrams per cubic 
meter) of a substance above which it is predicted that the general 
population, including susceptible individuals, could experience 
irreversible or other serious, long-lasting adverse health effects or 
an impaired ability to escape.'' Id.
    ERPG values are derived for use in emergency response, as described 
in the American Industrial Hygiene Association's ERP Committee document 
titled, ERPGS Procedures and Responsibilities (https://sp4m.aiha.org/insideaiha/GuidelineDevelopment/ERPG/Documents/ERP-SOPs2006.pdf), which 
states that, ``Emergency Response Planning Guidelines were developed 
for emergency planning and are intended as health based guideline 
concentrations for single exposures to chemicals.'' \10\ Id. at 1. The 
ERPG-1 value is defined as ``the maximum airborne concentration below 
which it is believed that nearly all individuals could be exposed for 
up to 1 hour without experiencing other than mild transient adverse 
health effects or without perceiving a clearly defined, objectionable 
odor.'' Id. at 2. Similarly, the ERPG-2 value is defined as ``the 
maximum airborne concentration below which it is believed that nearly 
all individuals could be exposed for up to one hour without 
experiencing or developing irreversible or other serious health effects 
or symptoms which could impair an individual's ability to take 
protective action.'' Id. at 1.
---------------------------------------------------------------------------

    \10\ ERP Committee Procedures and Responsibilities. November 1, 
2006. American Industrial Hygiene Association.
---------------------------------------------------------------------------

    As can be seen from the definitions above, the AEGL and ERPG values 
include the similarly-defined severity levels 1 and 2. For many 
chemicals, a severity level 1 value AEGL or ERPG has not been developed 
because the types of effects for these chemicals are not consistent 
with the AEGL-1/ERPG-1 definitions; in these instances, we compare 
higher severity level AEGL-2 or ERPG-2 values to our modeled exposure 
levels to screen for potential acute concerns. When AEGL-1/ERPG-1 
values are available, they are used in our acute risk assessments.
    Acute REL values for 1-hour exposure durations are typically lower 
than their corresponding AEGL-1 and ERPG-1 values. Even though their 
definitions are slightly different, AEGL-1 values are often the same as 
the corresponding ERPG-1 values, and AEGL-2 values are often equal to 
ERPG-2 values. Maximum HQ values from our acute screening risk 
assessments typically result when basing them on the acute REL value 
for a particular pollutant. In cases where our maximum acute HQ value 
exceeds 1, we also report the HQ value based on the next highest acute 
dose-response value (usually the AEGL-1 and/or the ERPG-1 value).
    To develop screening estimates of acute exposures in the absence of 
hourly emissions data, generally we first develop estimates of maximum 
hourly emissions rates by multiplying the average actual annual hourly 
emissions rates by a default factor to cover routinely variable 
emissions. We choose the factor to use partially based on process 
knowledge and engineering judgment. The factor chosen also reflects a 
Texas study of short-term emissions variability, which showed that most 
peak emission events in a heavily-industrialized four-county area 
(Harris, Galveston, Chambers and Brazoria Counties, Texas) were less 
than twice the annual average hourly emissions rate. The highest peak 
emissions event was 74 times the annual average hourly emissions rate, 
and the 99th percentile ratio of peak hourly emissions rate to the 
annual average hourly emissions rate was 9.\11\ Considering this 
analysis, to account for more than 99 percent of the peak hourly 
emissions, we apply a conservative screening multiplication factor of 
10 to the average annual hourly emissions rate in our acute exposure 
screening assessments as our default approach. However, we use a factor 
other than 10 if we have information that indicates that a different 
factor is appropriate for a particular source category. For this source 
category, we applied a multiplication factor of 10 to all emission 
sources except for HF emissions from the gypsum dewatering stacks and 
cooling ponds. The EPA used a multiplication factor of 1 for gypsum 
dewatering stacks and cooling ponds based upon the stability of HF 
releases from this emission source. Section III.A.2.a of this preamble 
as well as the memorandum, ``Emissions Data Used in Residual Risk 
Modeling: Phosphoric Acid Manufacturing and Phosphate Fertilizer 
Production,'' which is available in the docket for this rulemaking, 
discusses our rationale for choosing this factor.
---------------------------------------------------------------------------

    \11\ See https://www.tceq.state.tx.us/compliance/field_ops/eer/ or docket to access the source of these data.
---------------------------------------------------------------------------

    As part of our acute risk assessment process, for cases where acute 
HQ values from the screening step were less than or equal to 1 (even 
under the conservative assumptions of the screening analysis), acute 
impacts were deemed negligible and no further analysis was performed. 
In cases where an acute HQ from the screening step was greater than 1, 
additional site-specific data were considered to develop a more refined 
estimate of the potential for acute impacts of concern. For these 
source categories, the data refinements employed consisted of, in some 
cases, the use of a refined emissions multiplier for individual 
emission process groups to estimate the peak hourly emission rates in 
lieu of using the default emission multiplier of 10(x) the annual 
average 1-hour emission rate.
    For the two source categories, we conducted a review of the layout 
of emission points at the facilities to ensure they were located within 
the facility boundaries as well as to identify the maximum off-site 
acute impact receptor for the facilities that did not screen out during 
the initial base model run.
    Ideally, we would prefer to have continuous measurements over time 
to see how the emissions vary by each hour over an entire year. Having 
a frequency distribution of hourly emissions rates over a year would 
allow us to perform a probabilistic analysis to estimate potential 
threshold exceedances and their frequency of occurrence. Such an 
evaluation could include a more complete statistical treatment of the 
key parameters and elements adopted in this screening analysis. 
Recognizing that this level of data is rarely available, we instead 
rely on the multiplier approach.
    To better characterize the potential health risks associated with 
estimated acute exposures to HAP, and in response to a key 
recommendation from the SAB's peer review of the EPA's RTR risk 
assessment methodologies,\12\ we generally examine a wider range of 
available acute health metrics (e.g., RELs, AEGLs) than we do for our 
chronic risk assessments. This is in response to the SAB's 
acknowledgement

[[Page 66524]]

that there are generally more data gaps and inconsistencies in acute 
reference values than there are in chronic reference values. In some 
cases, when Reference Value Arrays \13\ for HAP have been developed, we 
consider additional acute values (i.e., occupational and international 
values) to provide a more complete risk characterization.
---------------------------------------------------------------------------

    \12\ The SAB peer review of RTR Risk Assessment Methodologies is 
available at: https://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf.
    \13\ U.S. EPA. (2009) Chapter 2.9 Chemical Specific Reference 
Values for Formaldehyde in Graphical Arrays of Chemical-Specific 
Health Effect Reference Values for Inhalation Exposures (Final 
Report). U.S. Environmental Protection Agency, Washington, DC, EPA/
600/R-09/061, and available online at https://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003.
---------------------------------------------------------------------------

4. How did we conduct the multipathway exposure and risk screening?
    The EPA conducted a screening analysis examining the potential for 
significant human health risks due to exposures via routes other than 
inhalation (i.e., ingestion). We first determined whether any sources 
in the source categories emitted any hazardous air pollutants known to 
be persistent and bioaccumulative in the environment (PB-HAP). The PB-
HAP compounds or compound classes are identified for the screening from 
the EPA's Air Toxics Risk Assessment Library (available at https://www2.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library).
    For the Phosphoric Acid Manufacturing source category, we 
identified PB-HAP emissions of cadmium compounds, Pb compounds, Hg 
compounds, POM and dioxin. For the Phosphate Fertilizer Production 
Source Category, we identified PB-HAP emissions of cadmium compounds, 
Pb compounds, and Hg compounds.
    Because one or more of these PB-HAP are emitted by at least one 
facility in the two source categories, we proceeded to the next step of 
the evaluation. In this step, we determined whether the facility-
specific emissions rates of the emitted PB-HAP were large enough to 
create the potential for significant non-inhalation human health risks 
under reasonable worst-case conditions. To facilitate this step, we 
developed emissions rate screening levels for several PB-HAP using a 
hypothetical upper-end screening exposure scenario developed for use in 
conjunction with the EPA's Total Risk Integrated Methodology. Fate, 
Transport and Ecological Exposure (TRIM.FaTE) model. The PB-HAP with 
emissions rate screening levels are: Pb, cadmium, chlorinated 
dibenzodioxins and furans, Hg compounds and POM. We conducted a 
sensitivity analysis on the screening scenario to ensure that its key 
design parameters would represent the upper end of the range of 
possible values, such that it would represent a conservative but not 
impossible scenario. The facility-specific emissions rates of each of 
these PB-HAP were compared to the emission rate screening levels for 
these PB-HAP to assess the potential for significant human health risks 
via non-inhalation pathways. We call this application of the TRIM.FaTE 
model the Tier I TRIM-screen or Tier I screen.
    For the purpose of developing emissions rates for our Tier I TRIM-
screen, we derived emission levels for these PB-HAP (other than Pb 
compounds) at which the maximum excess lifetime cancer risk would be 1-
in-1 million (i.e., for polychlorinated dibenzodioxins and furans and 
POM) or, for HAP that cause non-cancer health effects (i.e., cadmium 
compounds and Hg compounds), the maximum HQ would be 1. If the 
emissions rate of any PB-HAP included in the Tier I screen exceeds the 
Tier I screening emissions rate for any facility, we conduct a second 
screen, which we call the Tier II TRIM-screen or Tier II screen. In the 
Tier II screen, the location of each facility that exceeded the Tier I 
emission rate is used to refine the assumptions associated with the 
environmental scenario while maintaining the exposure scenario 
assumptions. We then adjusted the risk-based Tier I screening level for 
each PB-HAP for each facility based on an understanding of how exposure 
concentrations estimated for the screening scenario change with 
meteorology and environmental assumptions. PB-HAP emissions that do not 
exceed these new Tier II screening levels are considered to pose no 
unacceptable risks. When facilities exceed the Tier II screening 
levels, it does not mean that multipathway impacts are significant, 
only that we cannot rule out that possibility based on the results of 
the screen. These facilities may be further evaluated for multipathway 
risks using the TRIM.FaTE model.
    In evaluating the potential multi-pathway risk from emissions of Pb 
compounds, rather than developing a screening emissions rate for them, 
we compared maximum estimated chronic inhalation exposures with the 
level of the current NAAQS for Pb.\14\ Values below the level of the 
primary (health based) Pb NAAQS were considered to have a low potential 
for multi-pathway risk.
---------------------------------------------------------------------------

    \14\ In doing so, the EPA notes that the legal standard for a 
primary NAAQS--that a standard is requisite to protect public health 
and provide an adequate margin of safety (CAA section 109(b))--
differs from the CAA section 112(f) standard (requiring among other 
things that the standard provide an ``ample margin of safety''). 
However, the Pb NAAQS is a reasonable measure of determining risk 
acceptability (i.e., the first step of the Benzene NESHAP analysis) 
since it is designed to protect the most susceptible group in the 
human population--children, including children living near major 
lead emitting sources (73 FR 67002/3; 73 FR 67000/3; 73 FR 67005/1). 
In addition, applying the level of the primary Pb NAAQS at the risk 
acceptability step is conservative, since that primary Pb NAAQS 
reflects an adequate margin of safety.
---------------------------------------------------------------------------

    For further information on the multipathway analysis approach, see 
the memorandum, ``Draft Residual Risk Assessment for Phosphate 
Fertilizer Production and Phosphoric Acid Manufacturing,'' which is 
available in the docket for this action.
5. How did we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect
    The EPA has developed a screening approach to examine the potential 
for adverse environmental effects as required under section 
112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines ``adverse 
environmental effect'' as ``any significant and widespread adverse 
effect, which may reasonably be anticipated, to wildlife, aquatic life, 
or other natural resources, including adverse impacts on populations of 
endangered or threatened species or significant degradation of 
environmental quality over broad areas.''
b. Environmental HAP
    The EPA focuses on seven HAP, which we refer to as ``environmental 
HAP,'' in its screening analysis: Five PB-HAP and two acid gases. The 
five PB-HAP are cadmium, dioxins/furans, POM, Hg (both inorganic 
mercury and methyl mercury) and Pb compounds. The two acid gases are 
HCl and HF. The rationale for including these seven HAP in the 
environmental risk screening analysis is presented below.
    HAP that persist and bioaccumulate are of particular environmental 
concern because they accumulate in the soil, sediment and water. The 
PB-HAP are taken up, through sediment, soil, water, and/or ingestion of 
other organisms, by plants or animals (e.g., small fish) at the bottom 
of the food chain. As larger and larger predators consume these 
organisms, concentrations of the PB-HAP in the animal tissues increases 
as does the potential for adverse effects. The five PB-HAP we evaluate 
as part of

[[Page 66525]]

our screening analysis account for 99.8 percent of all PB-HAP emissions 
nationally from stationary sources (on a mass basis from the 2005 NEI).
    In addition to accounting for almost all of the mass of PB-HAP 
emitted, we note that the TRIM.FaTE model that we use to evaluate 
multipathway risk allows us to estimate concentrations of for cadmium 
compounds, dioxins/furans, POM and Hg in soil, sediment and water. For 
Pb compounds, we currently do not have the ability to calculate these 
concentrations using the TRIM.FaTE model. Therefore, to evaluate the 
potential for adverse environmental effects from Pb compounds, we 
compare the estimated HEM-modeled exposures from the source category 
emissions of Pb with the level of the secondary NAAQS for Pb.\15\ We 
consider values below the level of the secondary Pb NAAQS to be 
unlikely to cause adverse environmental effects.
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    \15\ The secondary Pb NAAQS is a reasonable measure of 
determining whether there is an adverse environmental effect since 
it was established considering ``effects on soils, water, crops, 
vegetation, man-made materials, animals, wildlife, weather, 
visibility and climate, damage to and deterioration of property, and 
hazards to transportation, as well as effects on economic values and 
on personal comfort and well-being.''
---------------------------------------------------------------------------

    Due to their well-documented potential to cause direct damage to 
terrestrial plants, we include two acid gases, HCl and HF, in the 
environmental screening analysis. According to the 2005 NEI, HCl and HF 
account for about 99 percent (on a mass basis) of the total acid gas 
HAP emitted by stationary sources in the U.S. In addition to the 
potential to cause direct damage to plants, high concentrations of HF 
in the air have been linked to fluorosis in livestock. Air 
concentrations of these HAP are already calculated as part of the human 
multipathway exposure and risk screening analysis using the HEM3-AERMOD 
air dispersion model, and we are able to use the air dispersion 
modeling results to estimate the potential for an adverse environmental 
effect.
    The EPA acknowledges that other HAP beyond the seven HAP discussed 
above may have the potential to cause adverse environmental effects. 
Therefore, the EPA may include other relevant HAP in its environmental 
risk screening in the future, as modeling science and resources allow. 
The EPA invites comment on the extent to which other HAP emitted by the 
source categories may cause adverse environmental effects. Such 
information should include references to peer-reviewed ecological 
effects benchmarks that are of sufficient quality for making regulatory 
decisions, as well as information on the presence of organisms located 
near facilities within the source category that such benchmarks 
indicate could be adversely affected.
c. Ecological Assessment Endpoints and Benchmarks for PB-HAP
    An important consideration in the development of the EPA's 
screening methodology is the selection of ecological assessment 
endpoints and benchmarks. Ecological assessment endpoints are defined 
by the ecological entity (e.g., aquatic communities including fish and 
plankton) and its attributes (e.g., frequency of mortality). Ecological 
assessment endpoints can be established for organisms, populations, 
communities or assemblages, and ecosystems.
    For PB-HAP (other than Pb compounds), we evaluated the following 
community-level ecological assessment endpoints to screen for organisms 
directly exposed to HAP in soils, sediment and water:
     Local terrestrial communities (i.e., soil invertebrates, 
plants) and populations of small birds and mammals that consume soil 
invertebrates exposed to PB-HAP in the surface soil.
     Local benthic (i.e., bottom sediment dwelling insects, 
amphipods, isopods and crayfish) communities exposed to PB-HAP in 
sediment in nearby water bodies.
     Local aquatic (water-column) communities (including fish 
and plankton) exposed to PB-HAP in nearby surface waters.
    For PB-HAP (other than Pb compounds), we also evaluated the 
following population-level ecological assessment endpoint to screen for 
indirect HAP exposures of top consumers via the bioaccumulation of HAP 
in food chains:
     Piscivorous (i.e., fish-eating) wildlife consuming PB-HAP-
contaminated fish from nearby water bodies.
    For cadmium compounds, dioxins/furans, POM and Hg, we identified 
the available ecological benchmarks for each assessment endpoint. An 
ecological benchmark represents a concentration of HAP (e.g., 0.77 ug 
of HAP per liter of water) that has been linked to a particular 
environmental effect level (e.g., a no-observed-adverse-effect level 
(NOAEL)) through scientific study. For PB-HAP we identified, where 
possible, ecological benchmarks at the following effect levels:
     Probable effect levels (PEL): Level above which adverse 
effects are expected to occur frequently.
     Lowest-observed-adverse-effect level (LOAEL): The lowest 
exposure level tested at which there are biologically significant 
increases in frequency or severity of adverse effects.
     NOAEL: The highest exposure level tested at which there 
are no biologically significant increases in the frequency or severity 
of adverse effect.
    We established a hierarchy of preferred benchmark sources to allow 
selection of benchmarks for each environmental HAP at each ecological 
assessment endpoint. In general, the EPA sources that are used at a 
programmatic level (e.g., Office of Water, Superfund Program) were 
used, if available. If not, the EPA benchmarks used in regional 
programs (e.g., Superfund) were used. If benchmarks were not available 
at a programmatic or regional level, we used benchmarks developed by 
other federal agencies (e.g., National Oceanic and Atmospheric 
Administration (NOAA) or state agencies.
    Benchmarks for all effect levels are not available for all PB-HAP 
and assessment endpoints. In cases where multiple effect levels were 
available for a particular PB-HAP and assessment endpoint, we use all 
of the available effect levels to help us to determine whether 
ecological risks exist and, if so, whether the risks could be 
considered significant and widespread.
d. Ecological Assessment Endpoints and Benchmarks for Acid Gases
    The environmental screening analysis also evaluated potential 
damage and reduced productivity of plants due to direct exposure to 
acid gases in the air. For acid gases, we evaluated the following 
ecological assessment endpoint:
     Local terrestrial plant communities with foliage exposed 
to acidic gaseous HAP in the air.
    The selection of ecological benchmarks for the effects of acid 
gases on plants followed the same approach as for PB-HAP (i.e., we 
examine all of the available chronic benchmarks). For HCl, the EPA 
identified chronic benchmark concentrations. We note that the benchmark 
for chronic HCl exposure to plants is greater than the reference 
concentration for chronic inhalation exposure for human health. This 
means that where the EPA includes regulatory requirements to prevent an 
exceedance of the reference concentration for human health, additional 
analyses for adverse environmental effects of HCl would not be 
necessary.

[[Page 66526]]

    For HF, the EPA identified chronic benchmark concentrations for 
plants and evaluated chronic exposures to plants in the screening 
analysis. High concentrations of HF in the air have also been linked to 
fluorosis in livestock. However, the HF concentrations at which 
fluorosis in livestock occur are higher than those at which plant 
damage begins. Therefore, the benchmarks for plants are protective of 
both plants and livestock.
e. Screening Methodology
    For the environmental risk screening analysis, the EPA first 
determined whether any facilities in the Phosphoric Acid Manufacturing 
source category and Phosphate Fertilizer Production source category 
emitted any of the seven environmental HAP. For the Phosphoric Acid 
Manufacturing source category, we identified emissions of cadmium, 
dioxin, Hg, Pb, POM, HCl and HF. For the Phosphate Fertilizer 
Production source category, we identified emissions of cadmium, Hg, Pb 
and HF.
    Because one or more of the seven environmental HAP evaluated are 
emitted by at least one facility in the source categories, we proceeded 
to the second step of the evaluation.
f. PB-HAP Methodology
    For cadmium, Hg, POM and dioxins/furans, the environmental 
screening analysis consists of two tiers, while Pb compounds are 
analyzed differently as discussed earlier. In the first tier, we 
determined whether the maximum facility-specific emission rates of each 
of the emitted environmental HAP were large enough to create the 
potential for adverse environmental effects under reasonable worst-case 
environmental conditions. These are the same environmental conditions 
used in the human multipathway exposure and risk screening analysis.
    To facilitate this step, TRIM.FaTE was run for each PB-HAP under 
hypothetical environmental conditions designed to provide 
conservatively high HAP concentrations. The model was set to maximize 
runoff from terrestrial parcels into the modeled lake, which in turn, 
maximized the chemical concentrations in the water, the sediment and 
the fish. The resulting media concentrations were then used to back-
calculate a screening level emission rate that corresponded to the 
relevant exposure benchmark concentration value for each assessment 
endpoint. To assess emissions from a facility, the reported emission 
rate for each PB-HAP was compared to the screening level emission rate 
for that PB-HAP for each assessment endpoint. If emissions from a 
facility do not exceed the Tier I screening level, the facility 
``passes'' the screen, and, therefore, is not evaluated further under 
the screening approach. If emissions from a facility exceed the Tier I 
screening level, we evaluate the facility further in Tier II.
    In Tier II of the environmental screening analysis, the emission 
rate screening levels are adjusted to account for local meteorology and 
the actual location of lakes in the vicinity of facilities that did not 
pass the Tier I screen. The modeling domain for each facility in the 
Tier II analysis consists of eight octants. Each octant contains 5 
modeled soil concentrations at various distances from the facility (5 
soil concentrations x 8 octants = total of 40 soil concentrations per 
facility) and 1 lake with modeled concentrations for water, sediment 
and fish tissue. In the Tier II environmental risk screening analysis, 
the 40 soil concentration points are averaged to obtain an average soil 
concentration for each facility for each PB-HAP. For the water, 
sediment and fish tissue concentrations, the highest value for each 
facility for each pollutant is used. If emission concentrations from a 
facility do not exceed the Tier II screening level, the facility passes 
the screen, and is typically not evaluated further. If emissions from a 
facility exceed the Tier II screening level, the facility does not pass 
the screen and, therefore, may have the potential to cause adverse 
environmental effects. Such facilities are evaluated further to 
investigate factors such as the magnitude and characteristics of the 
area of exceedance.
g. Acid Gas Methodology
    The environmental screening analysis evaluates the potential 
phytotoxicity and reduced productivity of plants due to chronic 
exposure to acid gases. The environmental risk screening methodology 
for acid gases is a single-tier screen that compares the average off-
site ambient air concentration over the modeling domain to ecological 
benchmarks for each of the acid gases. Because air concentrations are 
compared directly to the ecological benchmarks, emission-based 
screening levels are not calculated for acid gases as they are in the 
ecological risk screening methodology for PB-HAPs.
    For purposes of ecological risk screening, the EPA identifies a 
potential for adverse environmental effects to plant communities from 
exposure to acid gases when the average concentration of the HAP around 
a facility exceeds the LOAEL ecological benchmark. In such cases, we 
further investigate factors such as the magnitude and characteristics 
of the area of exceedance (e.g., land use of exceedance area, size of 
exceedance area) to determine if there is an adverse environmental 
effect.
    For further information on the environmental screening analysis 
approach, see the ``Draft Residual Risk Assessment for Phosphate 
Fertilizer Production and Phosphoric Acid Manufacturing'', which is 
available in the docket for this action.
6. How did we conduct facility-wide assessments?
    To put the source category risks in context, we typically examine 
the risks from the entire ``facility,'' where the facility includes all 
HAP-emitting operations within a contiguous area and under common 
control. In other words, we examine the HAP emissions not only from the 
source category emission points of interest, but also emissions of HAP 
from all other emission sources at the facility for which we have data. 
We examined ``facility-wide'' risks using 2005 NEI data and modeling as 
described in sections IV.B.5 and V.A.5 of this preamble.
    We analyzed risks due to the inhalation of HAP that are emitted 
``facility-wide'' for the populations residing within 50 km of each 
facility, consistent with the methods used for the source category 
analysis described above. For these facility-wide risk analyses, the 
modeled source category risks were compared to the facility-wide risks 
to determine the portion of facility-wide risks that could be 
attributed to each of the source categories addressed in this proposal. 
For the facilities in these source categories, we estimated the maximum 
inhalation cancer and chronic non-cancer risks associated with all HAP 
emissions sources at the facility, including emissions sources that are 
not part of the source categories but are located within a contiguous 
area and are under common control. We specifically examined the 
facility that was associated with the highest estimate of risk and 
determined the percentage of that risk attributable to the source 
category of interest. The results of these facility-wide assessments 
are summarized in sections IV and V of this preamble. The ``Draft 
Residual Risk Assessment for Phosphate Fertilizer Production and 
Phosphoric Acid Manufacturing'' available through the docket for this 
action provides the methodology and results of the facility-wide 
analyses, including all facility-wide risks and the percentage of 
source category contribution to facility-wide risks.

[[Page 66527]]

7. How did we consider uncertainties in risk assessment?
    In the Benzene NESHAP, we concluded that risk estimation 
uncertainty should be considered in our decision-making under the ample 
margin of safety framework. Uncertainty and the potential for bias are 
inherent in all risk assessments, including those performed for this 
proposal. Although uncertainty exists, we believe that our approach, 
which used conservative tools and assumptions, ensures that our 
decisions are health protective and environmentally protective. A brief 
discussion of the uncertainties in the RTR emissions datasets, 
dispersion modeling, inhalation exposure estimates and dose-response 
relationships follows below. A more thorough discussion of these 
uncertainties is included in the Draft Residual Risk Assessment for 
Phosphate Fertilizer Production and Phosphoric Acid Manufacturing, 
which is available in the docket for this action.
a. Uncertainties in the RTR Emissions Datasets
    Although the development of the RTR emissions datasets involved 
quality assurance/quality control processes, the accuracy of emissions 
values will vary depending on the source of the data, the degree to 
which data are incomplete or missing, the degree to which assumptions 
made to complete the datasets are accurate, errors in emission 
estimates and other factors. The emission estimates considered in this 
analysis generally are annual totals for certain years, and they do not 
reflect short-term fluctuations during the course of a year or 
variations from year to year. The estimates of peak hourly emission 
rates for the acute effects screening assessment were based on an 
emission adjustment factor applied to the average annual hourly 
emission rates, which are intended to account for emission fluctuations 
due to normal facility operations.
b. Uncertainties in Dispersion Modeling
    We recognize there is uncertainty in ambient concentration 
estimates associated with any model, including the EPA's recommended 
regulatory dispersion model, AERMOD. In using a model to estimated 
ambient pollutant concentrations, the user chooses certain options to 
apply. For RTR assessments, we select some model options that have the 
potential to overestimate ambient air concentrations (e.g., not 
including plume depletion or pollutant transformation). We select other 
model options that have the potential to underestimate ambient impacts 
(e.g., not including building downwash). Other options that we select 
have the potential to either under- or overestimate ambient levels 
(e.g., meteorology and receptor locations). On balance, considering the 
directional nature of the uncertainties commonly present in ambient 
concentrations estimated by dispersion models, the approach we apply in 
the RTR assessments should yield unbiased estimates of ambient HAP 
concentrations.
c. Uncertainties in Inhalation Exposure
    The EPA did not include the effects of human mobility on exposures 
in the assessment. Specifically, short-term mobility and long-term 
mobility between census blocks in the modeling domain were not 
considered.\16\ The approach of not considering short or long-term 
population mobility does not bias the estimate of the theoretical MIR 
(by definition), nor does it affect the estimate of cancer incidence 
because the total population number remains the same. It does, however, 
affect the shape of the distribution of individual risks across the 
affected population, shifting it toward higher estimated individual 
risks at the upper end and reducing the number of people estimated to 
be at lower risks, thereby increasing the estimated number of people at 
specific high risk levels (e.g., 1-in-10 thousand or 1-in-1 million).
---------------------------------------------------------------------------

    \16\ Short-term mobility is movement from one micro-environment 
to another over the course of hours or days. Long-term mobility is 
movement from one residence to another over the course of a 
lifetime.
---------------------------------------------------------------------------

    In addition, the assessment predicted the chronic exposures at the 
centroid of each populated census block as surrogates for the exposure 
concentrations for all people living in that block. Using the census 
block centroid to predict chronic exposures tends to over-predict 
exposures for people in the census block who live farther from the 
facility and under-predict exposures for people in the census block who 
live closer to the facility. Thus, using the census block centroid to 
predict chronic exposures may lead to a potential understatement or 
overstatement of the true maximum impact, but is an unbiased estimate 
of average risk and incidence. We reduce this uncertainty by analyzing 
large census blocks near facilities using aerial imagery and adjusting 
the location of the block centroid to better represent the population 
in the block, as well as adding additional receptor locations where the 
block population is not well represented by a single location.
    The assessment evaluates the cancer inhalation risks associated 
with pollutant exposures over a 70-year period, which is the assumed 
lifetime of an individual. In reality, both the length of time that 
modeled emission sources at facilities actually operate (i.e., more or 
less than 70 years) and the domestic growth or decline of the modeled 
industry (i.e., the increase or decrease in the number or size of 
domestic facilities) will influence the future risks posed by a given 
source or source category. Depending on the characteristics of the 
industry, these factors will, in most cases, result in an overestimate 
both in individual risk levels and in the total estimated number of 
cancer cases. However, in the unlikely scenario where a facility 
maintains, or even increases, its emissions levels over a period of 
more than 70 years, residents live beyond 70 years at the same 
location, and the residents spend most of their days at that location, 
then the cancer inhalation risks could potentially be underestimated. 
However, annual cancer incidence estimates from exposures to emissions 
from these sources would not be affected by the length of time an 
emissions source operates.
    The exposure estimates used in these analyses assume chronic 
exposures to ambient (outdoor) levels of pollutants. Because most 
people spend the majority of their time indoors, actual exposures may 
not be as high, depending on the characteristics of the pollutants 
modeled. For many of the HAP, indoor levels are roughly equivalent to 
ambient levels, but for very reactive pollutants or larger particles, 
indoor levels are typically lower. This factor has the potential to 
result in an overestimate of 25 to 30 percent of exposures.\17\
---------------------------------------------------------------------------

    \17\ U.S. EPA. National-Scale Air Toxics Assessment for 1996. 
(EPA 453/R-01-003; January 2001; page 85.)
---------------------------------------------------------------------------

    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that the EPA 
conducts as part of the risk review under section 112 of the CAA that 
should be highlighted. The accuracy of an acute inhalation exposure 
assessment depends on the simultaneous occurrence of independent 
factors that may vary greatly, such as hourly emissions rates, 
meteorology and the presence of humans at the location of the maximum 
concentration. In the acute screening assessment that we conduct under 
the RTR program, we assume that peak emissions from the source category 
and worst-case meteorological conditions co-occur, thus resulting in 
maximum ambient concentrations. These two

[[Page 66528]]

events are unlikely to occur at the same time, making these assumptions 
conservative. We then include the additional assumption that a person 
is located at this point during this same time period. For this source 
category, these assumptions would tend to be worst-case actual 
exposures as it is unlikely that a person would be located at the point 
of maximum exposure during the time when peak emissions and worst-case 
meteorological conditions occur simultaneously.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and non-cancer effects from both chronic and acute 
exposures. Some uncertainties may be considered quantitatively, and 
others generally are expressed in qualitative terms. We note as a 
preface to this discussion a point on dose-response uncertainty that is 
brought out in the EPA's 2005 Cancer Guidelines; \18\ namely, that 
``the primary goal of EPA actions is protection of human health; 
accordingly, as an Agency policy, risk assessment procedures, including 
default options that are used in the absence of scientific data to the 
contrary, should be health protective'' (EPA 2005 Cancer Guidelines, 
pages 1-7). This is the approach followed here as summarized in the 
next several paragraphs. A complete detailed discussion of 
uncertainties and variability in dose-response relationships is given 
in the Draft Residual Risk Assessment for Phosphate Fertilizer 
Production and Phosphoric Acid Manufacturing, which is available in the 
docket for this action.
---------------------------------------------------------------------------

    \18\ Guidelines for Carcinogen Risk Assessment, EPA/630/P-03/
001F, March 2005, Risk Assessment Forum, U.S. Environmental 
Protection Agency, Washington, DC.
---------------------------------------------------------------------------

    Cancer URE values used in our risk assessments are those that have 
been developed to generally provide an upper bound estimate of risk. 
That is, they represent a ``plausible upper limit to the true value of 
a quantity'' (although this is usually not a true statistical 
confidence limit).\19\ In some circumstances, the true risk could be as 
low as zero; however, in other circumstances the risk could be 
greater.\20\ When developing an upper bound estimate of risk and to 
provide risk values that do not underestimate risk, health-protective 
default approaches are generally used. To err on the side of ensuring 
adequate health protection, the EPA typically uses the upper bound 
estimates rather than lower bound or central tendency estimates in our 
risk assessments, an approach that may have limitations for other uses 
(e.g., priority-setting or expected benefits analysis).
---------------------------------------------------------------------------

    \19\ Upper bound, IRIS glossary (https://www.epa.gov/NCEA/iris/help_gloss.htm).
    \20\ An exception to this is the URE for benzene, which is 
considered to cover a range of values, each end of which is 
considered to be equally plausible, and which is based on maximum 
likelihood estimates.
---------------------------------------------------------------------------

    Chronic non-cancer RfC and reference dose (RfD) values represent 
chronic exposure levels that are intended to be health-protective 
levels. Specifically, these values provide an estimate (with 
uncertainty spanning perhaps an order of magnitude) of a continuous 
inhalation exposure (RfC) or a daily oral exposure (RfD) to the human 
population (including sensitive subgroups) that is likely to be without 
an appreciable risk of deleterious effects during a lifetime. To derive 
values that are intended to be ``without appreciable risk,'' the 
methodology relies upon an uncertainty factor (UF) approach (U.S. EPA, 
1993, 1994) 21 22 which considers uncertainty, variability 
and gaps in the available data. The UF are applied to derive reference 
values that are intended to protect against appreciable risk of 
deleterious effects. The UF are commonly default values,\23\ e.g., 
factors of 10 or 3, used in the absence of compound-specific data; 
where data are available, UF may also be developed using compound-
specific information. When data are limited, more assumptions are 
needed and more UF are used. Thus, there may be a greater tendency to 
overestimate risk in the sense that further study might support 
development of reference values that are higher (i.e., less potent) 
because fewer default assumptions are needed. However, for some 
pollutants, it is possible that risks may be underestimated.
---------------------------------------------------------------------------

    \21\ U.S. EPA. Reference Dose (RfD): Description and Use in 
Health Risk Assessments. Dated March 1993.
    \22\ U.S. EPA. Methods for Derivation of Inhalation Reference 
Concentrations and Application of Inhalation Dosimetry. EPA/600/8-
90/066F. Dated October 1994.
    \23\ According to the NRC report, Science and Judgment in Risk 
Assessment (NRC, 1994) ``[Default] options are generic approaches, 
based on general scientific knowledge and policy judgment, that are 
applied to various elements of the risk assessment process when the 
correct scientific model is unknown or uncertain.'' The 1983 NRC 
report, Risk Assessment in the Federal Government: Managing the 
Process, defined default option as ``the option chosen on the basis 
of risk assessment policy that appears to be the best choice in the 
absence of data to the contrary'' (NRC, 1983a, p. 63). Therefore, 
default options are not rules that bind the agency; rather, the 
agency may depart from them in evaluating the risks posed by a 
specific substance when it believes this to be appropriate. In 
keeping with the EPA's goal of protecting public health and the 
environment, default assumptions are used to ensure that risk to 
chemicals is not underestimated (although defaults are not intended 
to overtly overestimate risk). See EPA, 2004, An Examination of EPA 
Risk Assessment Principles and Practices, EPA/100/B-04/001 available 
at: https://www.epa.gov/osa/pdfs/ratf-final.pdf.
---------------------------------------------------------------------------

    While collectively termed ``UF,'' these factors account for a 
number of different quantitative considerations when using observed 
animal (usually rodent) or human toxicity data in the development of 
the RfC. The UF are intended to account for: (1) Variation in 
susceptibility among the members of the human population (i.e., inter-
individual variability); (2) uncertainty in extrapolating from 
experimental animal data to humans (i.e., interspecies differences); 
(3) uncertainty in extrapolating from data obtained in a study with 
less-than-lifetime exposure (i.e., extrapolating from sub-chronic to 
chronic exposure); (4) uncertainty in extrapolating the observed data 
to obtain an estimate of the exposure associated with no adverse 
effects; and (5) uncertainty when the database is incomplete or there 
are problems with the applicability of available studies.
    Many of the UF used to account for variability and uncertainty in 
the development of acute reference values are quite similar to those 
developed for chronic durations, but they more often use individual UF 
values that may be less than 10. The UF are applied based on chemical-
specific or health effect-specific information (e.g., simple irritation 
effects do not vary appreciably between human individuals, hence a 
value of 3 is typically used), or based on the purpose for the 
reference value (see the following paragraph). The UF applied in acute 
reference value derivation include: (1) Heterogeneity among humans; (2) 
uncertainty in extrapolating from animals to humans; (3) uncertainty in 
lowest observed adverse effect (exposure) level to no observed adverse 
effect (exposure) level adjustments; and (4) uncertainty in accounting 
for an incomplete database on toxic effects of potential concern. 
Additional adjustments are often applied to account for uncertainty in 
extrapolation from observations at one exposure duration (e.g., 4 
hours) to derive an acute reference value at another exposure duration 
(e.g., 1 hour).
    Not all acute reference values are developed for the same purpose 
and care must be taken when interpreting the results of an acute 
assessment of human health effects relative to the reference value or 
values being exceeded. Where relevant to the estimated exposures, the 
lack of short-term dose-response values at different levels of severity 
should be factored into

[[Page 66529]]

the risk characterization as potential uncertainties.
    For a group of compounds that are unspeciated (e.g., glycol 
ethers), we conservatively use the most protective reference value of 
an individual compound in that group to estimate risk. Similarly, for 
an individual compound in a group (e.g., ethylene glycol diethyl ether) 
that does not have a specified reference value, we also apply the most 
protective reference value from the other compounds in the group to 
estimate risk.
e. Uncertainties in the Multipathway Assessment
    For each source category, we generally rely on site-specific levels 
of PB-HAP emissions to determine whether a refined assessment of the 
impacts from multipathway exposures is necessary. This determination is 
based on the results of a two-tiered screening analysis that relies on 
the outputs from models that estimate environmental pollutant 
concentrations and human exposures for 4 PB-HAP. Two important types of 
uncertainty associated with the use of these models in RTR risk 
assessments and inherent to any assessment that relies on environmental 
modeling are model uncertainty and input uncertainty.\24\
---------------------------------------------------------------------------

    \24\ In the context of this discussion, the term ``uncertainty'' 
as it pertains to exposure and risk encompasses both variability in 
the range of expected inputs and screening results due to existing 
spatial, temporal, and other factors, as well as uncertainty in 
being able to accurately estimate the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the selected models are 
appropriate for the assessment being conducted and whether they 
adequately represent the actual processes that might occur for that 
situation. An example of model uncertainty is the question of whether 
the model adequately describes the movement of a pollutant through the 
soil. This type of uncertainty is difficult to quantify. However, based 
on feedback received from previous EPA Science Advisory Board reviews 
and other reviews, we are confident that the models used in the screen 
are appropriate and state-of-the-art for the multipathway risk 
assessments conducted in support of RTR.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
I of the multipathway screen, we configured the models to avoid 
underestimating exposure and risk. This was accomplished by selecting 
upper-end values from nationally-representative data sets for the more 
influential parameters in the environmental model, including selection 
and spatial configuration of the area of interest, lake location and 
size, meteorology, surface water and soil characteristics and structure 
of the aquatic food web. We also assume an ingestion exposure scenario 
and values for human exposure factors that represent reasonable maximum 
exposures.
    In Tier II of the multipathway assessment, we refine the model 
inputs to account for meteorological patterns in the vicinity of the 
facility versus using upper-end national values and we identify the 
actual location of lakes near the facility rather than the default lake 
location that we apply in Tier I. By refining the screening approach in 
Tier II to account for local geographical and meteorological data, we 
decrease the likelihood that concentrations in environmental media are 
overestimated, thereby increasing the usefulness of the screen. The 
assumptions and the associated uncertainties regarding the selected 
ingestion exposure scenario are the same for Tier I and Tier II.
    For both Tiers I and II of the multipathway assessment, our 
approach to addressing model input uncertainty is generally cautious. 
We choose model inputs from the upper end of the range of possible 
values for the influential parameters used in the models, and we assume 
that the exposed individual exhibits ingestion behavior that would lead 
to a high total exposure. This approach reduces the likelihood of not 
identifying high risks for adverse impacts.
    Despite the uncertainties, when individual pollutants or facilities 
do screen out, we are confident that the potential for adverse 
multipathway impacts on human health is very low. On the other hand, 
when individual pollutants or facilities do not screen out, it does not 
mean that multipathway impacts are significant, only that we cannot 
rule out that possibility and that a refined multipathway analysis for 
the site might be necessary to obtain a more accurate risk 
characterization for the source category.
    For further information on uncertainties and the Tier I and II 
screening methods, refer to the risk document, Appendix 5, ``Technical 
Support Document for TRIM-Based Multipathway Tiered Screening 
Methodology for RTR.''
f. Uncertainties in the Environmental Risk Screening Assessment
    For each source category, we generally rely on site-specific levels 
of environmental HAP emissions to perform an environmental screening 
assessment. The environmental screening assessment is based on the 
outputs from models that estimate environmental HAP concentrations. The 
same models, specifically the TRIM.FaTE multipathway model and the 
AERMOD air dispersion model, are used to estimate environmental HAP 
concentrations for both the human multipathway screening analysis and 
for the environmental screening analysis. Therefore, both screening 
assessments have similar modeling uncertainties.
    Two important types of uncertainty associated with the use of these 
models in RTR environmental screening assessments--and inherent to any 
assessment that relies on environmental modeling--are model uncertainty 
and input uncertainty.\25\
---------------------------------------------------------------------------

    \25\ In the context of this discussion, the term 
``uncertainty,'' as it pertains to exposure and risk assessment, 
encompasses both variability in the range of expected inputs and 
screening results due to existing spatial, temporal, and other 
factors, as well as uncertainty in being able to accurately estimate 
the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the selected models are 
appropriate for the assessment being conducted and whether they 
adequately represent the movement and accumulation of environmental HAP 
emissions in the environment. For example, does the model adequately 
describe the movement of a pollutant through the soil? This type of 
uncertainty is difficult to quantify. However, based on feedback 
received from previous EPA SAB reviews and other reviews, we are 
confident that the models used in the screen are appropriate and state-
of-the-art for the environmental risk assessments conducted in support 
of our RTR analyses.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
I of the environmental screen for PB-HAP, we configured the models to 
avoid underestimating exposure and risk to reduce the likelihood that 
the results indicate the risks are lower than they actually are. This 
was accomplished by selecting upper-end values from nationally-
representative data sets for the more influential parameters in the 
environmental model, including selection and spatial configuration of 
the area of interest, the location and size of any bodies of water, 
meteorology, surface water and soil characteristics and structure of 
the aquatic food web. In Tier I, we used the maximum facility-specific 
emissions for the PB-HAP (other than Pb compounds, which were evaluated 
by comparison to the secondary Pb NAAQS) that were

[[Page 66530]]

included in the environmental screening assessment and each of the 
media when comparing to ecological benchmarks. This is consistent with 
the conservative design of Tier I of the screen. In Tier II of the 
environmental screening analysis for PB-HAP, we refine the model inputs 
to account for meteorological patterns in the vicinity of the facility 
versus using upper-end national values, and we identify the locations 
of water bodies near the facility location. By refining the screening 
approach in Tier II to account for local geographical and 
meteorological data, we decrease the likelihood that concentrations in 
environmental media are overestimated, thereby increasing the 
usefulness of the screen. To better represent widespread impacts, the 
modeled soil concentrations are averaged in Tier II to obtain one 
average soil concentration value for each facility and for each PB-HAP. 
For PB-HAP concentrations in water, sediment and fish tissue, the 
highest value for each facility for each pollutant is used.
    For the environmental screening assessment for acid gases, we 
employ a single-tiered approach. We use the modeled air concentrations 
and compare those with ecological benchmarks.
    For both Tiers I and II of the environmental screening assessment, 
our approach to addressing model input uncertainty is generally 
cautious. We choose model inputs from the upper end of the range of 
possible values for the influential parameters used in the models, and 
we assume that the exposed individual exhibits ingestion behavior that 
would lead to a high total exposure. This approach reduces the 
likelihood of not identifying potential risks for adverse environmental 
impacts.
    Uncertainty also exists in the ecological benchmarks for the 
environmental risk screening analysis. We established a hierarchy of 
preferred benchmark sources to allow selection of benchmarks for each 
environmental HAP at each ecological assessment endpoint. In general, 
EPA benchmarks used at a programmatic level (e.g., Office of Water, 
Superfund Program) were used if available. If not, we used EPA 
benchmarks used in regional programs (e.g., Superfund Program). If 
benchmarks were not available at a programmatic or regional level, we 
used benchmarks developed by other agencies (e.g., NOAA) or by state 
agencies.
    In all cases (except for Pb compounds, which were evaluated through 
a comparison to the NAAQS), we searched for benchmarks at the following 
three effect levels, as described in section III.A.5 of this preamble:
    1. A no-effect level (i.e., NOAEL).
    2. Threshold-effect level (i.e., LOAEL).
    3. Probable effect level (i.e., PEL).
    For some ecological assessment endpoint/environmental HAP 
combinations, we could identify benchmarks for all three effect levels, 
but for most, we could not. In one case, where different agencies 
derived significantly different numbers to represent a threshold for 
effect, we included both. In several cases, only a single benchmark was 
available. In cases where multiple effect levels were available for a 
particular PB-HAP and assessment endpoint, we used all of the available 
effect levels to help us to determine whether risk exists and if the 
risks could be considered significant and widespread.
    The EPA evaluates the following seven HAP in the environmental risk 
screening assessment: Cadmium, dioxins/furans, POM, Hg (both inorganic 
Hg and methyl Hg), Pb compounds, HCl and HF, where applicable. These 
seven HAP represent pollutants that can cause adverse impacts for 
plants and animals either through direct exposure to HAP in the air or 
through exposure to HAP that is deposited from the air onto soils and 
surface waters. These seven HAP also represent those HAP for which we 
can conduct a meaningful environmental risk screening assessment. For 
other HAP not included in our screening assessment, the model has not 
been parameterized such that it can be used for that purpose. In some 
cases, depending on the HAP, we may not have appropriate multipathway 
models that allow us to predict the concentration of that pollutant. 
The EPA acknowledges that other HAP beyond the seven HAP that we are 
evaluating may have the potential to cause adverse environmental 
effects and, therefore, the EPA may evaluate other relevant HAP in the 
future, as modeling science and resources allow.
    Further information on uncertainties and the Tier I and II 
environmental screening methods, is provided in Appendix 5 of the 
document, ``Technical Support Document for TRIM-Based Multipathway 
Tiered Screening Methodology for RTR: Summary of Approach and 
Evaluation.'' Also, see the memorandum, ``Draft Residual Risk 
Assessment for Phosphate Fertilizer Production and Phosphoric Acid 
Manufacturing,'' which is available in the docket for this action.

B. How did we consider the risk results in making decisions for this 
proposal?

    As discussed in section II.A of this preamble, in evaluating and 
developing standards under CAA section 112(f)(2), we apply a two-step 
process to address residual risk. In the first step, the EPA determines 
whether risks are acceptable. This determination ``considers all health 
information, including risk estimation uncertainty, and includes a 
presumptive limit on maximum individual lifetime [cancer] risk (MIR) 
\26\ of approximately [1-in-10 thousand] [i.e., 100-in-1 million].'' 54 
FR 38045, September 14, 1989. If risks are unacceptable, the EPA must 
determine the emissions standards necessary to bring risks to an 
acceptable level without considering costs. In the second step of the 
process, the EPA considers whether the emissions standards provide an 
ample margin of safety ``in consideration of all health information, 
including the number of persons at risk levels higher than 
approximately 1-in-1 million, as well as other relevant factors, 
including costs and economic impacts, technological feasibility, and 
other factors relevant to each particular decision.'' Id. The EPA must 
promulgate emission standards necessary to provide an ample margin of 
safety. After conducting the ample margin of safety analysis, we 
consider whether a more stringent standard is necessary to prevent, 
taking into consideration costs, energy, safety and other relevant 
factors, an adverse environmental effect.
---------------------------------------------------------------------------

    \26\ Although defined as ``maximum individual risk,'' MIR refers 
only to cancer risk. MIR, one metric for assessing cancer risk, is 
the estimated risk where an individual exposed to the maximum level 
of a pollutant for a lifetime.
---------------------------------------------------------------------------

    In past residual risk actions, the EPA considered a number of human 
health risk metrics associated with emissions from the categories under 
review, including the MIR, the number of persons in various risk 
ranges, cancer incidence, the maximum non-cancer HI and the maximum 
acute non-cancer hazard. See, e.g., 72 FR 25138, May 3, 2007; 71 FR 
42724, July 27, 2006. The EPA considered this health information for 
both actual and allowable emissions. See, e.g., 75 FR 65068, October 
21, 2010; 75 FR 80220, December 21, 2010; 76 FR 29032, May 19, 2011. 
The EPA also discussed risk estimation uncertainties and considered the 
uncertainties in the determination of acceptable risk and ample margin 
of safety in these past actions. The EPA considered this same type of 
information in support of this action.
    The agency is considering these various measures of health 
information

[[Page 66531]]

to inform our determinations of risk acceptability and ample margin of 
safety under CAA section 112(f). As explained in the Benzene NESHAP, 
``the first step judgment on acceptability cannot be reduced to any 
single factor'' and, thus, ``[t]he Administrator believes that the 
acceptability of risk under [previous] section 112 is best judged on 
the basis of a broad set of health risk measures and information.'' 54 
FR 38046, September 14, 1989. Similarly, with regard to the ample 
margin of safety determination, ``the Agency again considers all of the 
health risk and other health information considered in the first step. 
Beyond that information, additional factors relating to the appropriate 
level of control will also be considered, including cost and economic 
impacts of controls, technological feasibility, uncertainties, and any 
other relevant factors.'' Id.
    The Benzene NESHAP approach provides flexibility regarding factors 
the EPA may consider in making determinations and how the EPA may weigh 
those factors for each source category. In responding to comment on our 
policy under the Benzene NESHAP, the EPA explained that:

``[t]he policy chosen by the Administrator permits consideration of 
multiple measures of health risk. Not only can the MIR figure be 
considered, but also incidence, the presence of non-cancer health 
effects, and the uncertainties of the risk estimates. In this way, 
the effect on the most exposed individuals can be reviewed as well 
as the impact on the general public. These factors can then be 
weighed in each individual case. This approach complies with the 
Vinyl Chloride mandate that the Administrator ascertain an 
acceptable level of risk to the public by employing [her] expertise 
to assess available data. It also complies with the Congressional 
intent behind the CAA, which did not exclude the use of any 
particular measure of public health risk from the EPA's 
consideration with respect to CAA section 112 regulations, and 
thereby implicitly permits consideration of any and all measures of 
health risk which the Administrator, in [her] judgment, believes are 
appropriate to determining what will `protect the public health'.''

    See 54 FR at 38057, September 14, 1989. Thus, the level of the MIR 
is only one factor to be weighed in determining acceptability of risks. 
The Benzene NESHAP explained that ``an MIR of approximately one in 10 
thousand should ordinarily be the upper end of the range of 
acceptability. As risks increase above this benchmark, they become 
presumptively less acceptable under CAA section 112, and would be 
weighed with the other health risk measures and information in making 
an overall judgment on acceptability. Or, the Agency may find, in a 
particular case, that a risk that includes MIR less than the 
presumptively acceptable level is unacceptable in the light of other 
health risk factors.'' Id. at 38045. Similarly, with regard to the 
ample margin of safety analysis, the EPA stated in the Benzene NESHAP 
that: ``EPA believes the relative weight of the many factors that can 
be considered in selecting an ample margin of safety can only be 
determined for each specific source category. This occurs mainly 
because technological and economic factors (along with the health-
related factors) vary from source category to source category.'' Id. at 
38061. We also consider the uncertainties associated with the various 
risk analyses, as discussed earlier in this preamble, in our 
determinations of acceptability and ample margin of safety.
    The EPA notes that it has not considered certain health information 
to date in making residual risk determinations. At this time, we do not 
attempt to quantify those HAP risks that may be associated with 
emissions from other facilities that do not include the source 
categories in question, mobile source emissions, natural source 
emissions, persistent environmental pollution or atmospheric 
transformation in the vicinity of the sources in these categories.
    The agency understands the potential importance of considering an 
individual's total exposure to HAP in addition to considering exposure 
to HAP emissions from the source category and facility. We recognize 
that such consideration may be particularly important when assessing 
non-cancer risks, where pollutant-specific exposure health reference 
levels (e.g., RfCs) are based on the assumption that thresholds exist 
for adverse health effects. For example, the agency recognizes that, 
although exposures attributable to emissions from a source category or 
facility alone may not indicate the potential for increased risk of 
adverse non-cancer health effects in a population, the exposures 
resulting from emissions from the facility in combination with 
emissions from all of the other sources (e.g., other facilities) to 
which an individual is exposed may be sufficient to result in increased 
risk of adverse non-cancer health effects. In May 2010, the SAB advised 
the EPA ``that RTR assessments will be most useful to decision makers 
and communities if results are presented in the broader context of 
aggregate and cumulative risks, including background concentrations and 
contributions from other sources in the area.'' \27\
---------------------------------------------------------------------------

    \27\ EPA's responses to this and all other key recommendations 
of the SAB's advisory on RTR risk assessment methodologies (which is 
available at: https://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-1-007-unsigned.pdf) 
are outlined in a memorandum to this rulemaking docket from David 
Guinnup titled, EPA's Actions in Response to the Key Recommendations 
of the SAB Review of RTR Risk Assessment Methodologies.
---------------------------------------------------------------------------

    In response to the SAB recommendations, the EPA is incorporating 
cumulative risk analyses into its RTR risk assessments, including those 
reflected in this proposal. The agency is: (1) Conducting facility-wide 
assessments, which include source category emission points as well as 
other emission points within the facilities; (2) considering sources in 
the same category whose emissions result in exposures to the same 
individuals; and (3) for some persistent and bioaccumulative 
pollutants, analyzing the ingestion route of exposure. In addition, the 
RTR risk assessments have always considered aggregate cancer risk from 
all carcinogens and aggregate non-cancer HI from all non-carcinogens 
affecting the same target organ system.
    Although we are interested in placing source category and facility-
wide HAP risks in the context of total HAP risks from all sources 
combined in the vicinity of each source, we are concerned about the 
uncertainties of doing so. Because of the contribution to total HAP 
risk from emission sources other than those that we have studied in 
depth during this RTR review such estimates of total HAP risks would 
have significantly greater associated uncertainties than the source 
category or facility-wide estimates. Such aggregate or cumulative 
assessments would compound those uncertainties, making the assessments 
too unreliable.

C. How did we perform the technology reviews for the NESHAP and NSPS?

    Our technology review focused on the identification and evaluation 
of developments in practices, processes and control technologies that 
have occurred since the NESHAP standards were promulgated. We also 
focused on the emission limitations and percent reductions achieved in 
practice that have occurred since the NSPS standards were promulgated. 
Where we identified such developments, in order to inform our decision 
of whether it is ``necessary'' to revise the emissions standards, we 
analyzed the technical feasibility of applying these developments and 
the estimated costs, energy implications, non-air environmental 
impacts, as well as

[[Page 66532]]

considering the emission reductions. For the NEHAP, we also considered 
the appropriateness of applying controls to new sources versus 
retrofitting existing sources.
    Based on our analyses of the available data and information, we 
identified potential developments in practices, processes and control 
technologies. For this exercise, we considered any of the following to 
be a ``development'':
     Any add-on control technology or other equipment that was 
not identified and considered during development of the original NESHAP 
and NSPS.
     Any improvements in add-on control technology or other 
equipment (that were identified and considered during development of 
the original NESHAP and NSPS) that could result in additional emissions 
reduction.
     Any work practice or operational procedure that was not 
identified or considered during development of the original NESHAP and 
NSPS.
     Any process change or pollution prevention alternative 
that could be broadly applied to the industry and that was not 
identified or considered during development of the original NESHAP and 
NSPS.
     Any significant changes in the cost (including cost 
effectiveness) of applying controls (including controls the EPA 
considered during the development of the original NESHAP and NSPS).
    In addition to reviewing the practices, processes or control 
technologies that were considered at the time we developed the 1999 
Phosphoric Acid Manufacturing and Phosphate Fertilizer Production 
NESHAP (i.e., NESHAP subpart AA and NESHAP subpart BB), we reviewed a 
variety of data sources in our investigation of potential practices, 
processes or controls to consider. Among the data sources we reviewed 
were the NESHAP for various industries that were promulgated since the 
NESHAP and NSPS standards being reviewed in this action. We reviewed 
the regulatory requirements and/or technical analyses associated with 
these regulatory actions to identify any practices, processes and 
control technologies considered in these efforts that could be applied 
to emission sources in the Phosphoric Acid Manufacturing and Phosphate 
Fertilizer Production source categories as well as the costs, non-air 
impacts and energy implications associated with the use of these 
technologies.
    We also consulted the EPA's RBLC to identify potential technology 
advances. Control technologies, classified as Reasonably Available 
Control Technology (RACT), Best Available Control Technology (BACT), or 
Lowest Achievable Emissions Rate (LAER) apply to stationary sources 
depending on whether the sources are existing or new, and depending on 
the size, age and location of the facility. BACT and LAER (and 
sometimes RACT) are determined on a case-by-case basis, usually by 
state or local permitting agencies. The EPA established the RBLC to 
provide a central database of air pollution technology information 
(including technologies required in source-specific permits) to promote 
the sharing of information among permitting agencies and to aid in 
identifying future possible control technology options that might apply 
broadly to numerous sources within a category or apply only on a 
source-by-source basis. The RBLC contains over 5,000 air pollution 
control permit determinations that can help identify appropriate 
technologies to mitigate many air pollutant emission streams. We 
searched this database to determine whether it contained any practices, 
processes or control technologies that are applicable to the types of 
processes covered by the phosphoric acid and phosphate fertilizer 
NESHAP and NSPS.
    Additionally, we requested information from facilities regarding 
developments in practices, processes or control technology. Finally, we 
reviewed information from other sources, such as state and/or local 
permitting agency databases and industry-supported databases.

IV. Analytical Results and Proposed Decisions for the Phosphoric Acid 
Manufacturing Source Category

A. What actions are we taking pursuant to CAA sections 112(d)(2) and 
112(d)(3) for the Phosphoric Acid Manufacturing source category?

1. MACT and Work Practice Standards for Phosphate Rock Dryers and 
Calciners
    We are proposing MACT standards pursuant to CAA section 112(d)(2) 
and (d)(3), and work practice standards pursuant to CAA section 112(h), 
for phosphate rock calciners, an emissions source that was regulated 
under the initial MACT standard for PM only, and adding pollutants, Hg 
and HF, that were not regulated under the initial NESHAP subpart AA. 
Under CAA section 112(d)(3), the EPA is required to promulgate 
emissions limits for all HAP emitted from major source categories (see 
National Lime v. EPA, 233 F. 3d 625, 634 (D.C. Cir. 2000); see also 
Sierra Club v. EPA, 479 F. 3d 875, 878 and 883 (D.C. Cir. 2007) 
(finding that the EPA must set standards for HAP even if they are not 
currently controlled with technology and that the agency may not set 
``no emissions reductions'' MACT floors).
    The United States Court of Appeals for the District of Columbia 
Circuit has also held that the EPA may permissibly amend improper MACT 
determinations, including amendments to improperly promulgated floor 
determinations, using its authority under CAA section 112(d)(2) and 
(3). Medical Waste Institute v. EPA, 645 F. 3d 420, 425-27 (D.C. Cir. 
2011). National Lime, 233 F. 3d at 633-34; see also Medical Waste 
Incinerator 645 F. 3d at 426 (resetting MACT floor, based on post-
compliance data, permissible when originally-established floor was 
improperly established, and permissibility of the EPA's action does not 
turn on whether the prior standard was remanded or vacated); Portland 
Cement Ass'n v. EPA, 665 F.3d 177 at 189 (the EPA may reassess its 
standards including revising existing floors).
    Phosphate rock dryers are no longer used in the manufacture of 
phosphoric acid or phosphate fertilizers. Rock dryers were previously 
used in the industry in the manufacture of GTSP. Because there are no 
longer any U.S. producers of GTSP, the rock dryers that were previously 
used in this industry are no longer in operation. In response to our 
April 2010 CAA section 114 request, we received emissions data for one 
dryer that is currently used in the production of defluorinated 
phosphate rock, which is subsequently used in the production of animal 
feed products. Because this process is not part of the regulated source 
categories, Phosphoric Acid or Phosphate Fertilizer NESHAP, these data 
were not used to set emissions limits and the EPA is not proposing 
revised emissions limits for rock dryers.
a. Determination of Emission Standards for Mercury From Phosphate Rock 
Calciners
    The 1999 Phosphoric Acid Manufacturing NESHAP (i.e., NESHAP subpart 
AA) specified emissions limits for metal HAP (e.g., arsenic, cadmium, 
Pb, Hg) from phosphate rock dryers and phosphate rock calciners in 
terms of a PM emissions limit (i.e., PM is used as a surrogate for all 
metal HAP). However, in this source category, PM is an improper 
surrogate for Hg. Therefore, we are eliminating the use of PM as a 
surrogate for Hg and proposing a Hg emission limit for phosphate rock 
calciners. Based on information provided by industry, rock dryers are 
no longer used in the production of phosphoric acid and their future 
use is

[[Page 66533]]

not anticipated, so there are no emissions from rock dryers for this 
source category. Therefore, we are not proposing a Hg emission limit 
for rock dryers. We are retaining the PM standard as a surrogate for 
other HAP metal emissions from phosphate rock calciners.
    In general, MACT floor analyses involve an assessment of the 
emissions from the best-performing sources in a source category using 
the available emissions information. For each source category, the 
assessment involves a review of emissions data with an appropriate 
accounting for emissions variability. Various methods of estimating 
emissions can be used if the methods can be shown to provide reasonable 
estimates of the actual emissions performance of a source or sources.
    The MACT standards for existing sources must be at least as 
stringent as the average emissions limitation achieved by the best-
performing 12 percent of existing sources (for which the Administrator 
has emissions information) or the best-performing five sources for 
source categories or subcategories with fewer than 30 sources (CAA 
section 112(d)(3)(A) and (d)(3)(B)). For new sources, MACT standards 
must be at least as stringent as the control level achieved in practice 
by the best-controlled similar source (CAA section 112(d)(3)). The EPA 
must also consider more stringent ``beyond-the-floor'' control options. 
When considering beyond-the-floor options, the EPA must consider not 
only the maximum degree of reduction in emissions of HAP, but must take 
into account costs, energy, and non-air quality health and 
environmental impacts.
    In 2014, only one facility operates phosphate rock calciners. In 
response to the April 2010 CAA section 114 request, the facility 
provided Hg emissions testing results for one of their six calciners to 
the EPA. In addition, the facility provided Hg emissions testing 
results for another, previously untested calciner in response to the 
January 2014 CAA section 114 request. As a result, the EPA had two 
datasets (at one facility) on which to base the MACT floors for Hg for 
new and existing phosphate rock calciners. However, calciner Hg 
emissions are the result of Hg contained in the fuel and raw materials. 
Because the six calciners are designed to be identical and use the same 
raw materials and fuels, Hg emissions from the six calciners are 
expected to be identical. This determination is consistent with the 
June 13, 2002, amendments to the NESHAP subpart AA (67 FR 40814) when 
the EPA could not find any reason to believe that the six calciners are 
not identical in regards to particulate emissions. In the preamble to 
the 2002 amendments, we concluded that factors other than the MACT 
technology (e.g., the source of the rock input, operator training 
experience) do not affect emission levels and that the calciners were 
designed to be identical. For this reason, all the data from the 
calciners were combined into one dataset to determine both new and 
existing MACT floors.
    To determine the MACT floors for phosphate rock calciners, we used 
the arithmetic average of all the available emissions data from the 
2010 and 2014 data requests and accounted for emissions variability. We 
accounted for emissions variability in setting floors not only because 
variability is an aspect of performance, but because it is reasonable 
to assess performance over time and to account for test method 
variability. The United States Court of Appeals for the District of 
Columbia Circuit has recognized that the EPA may consider variability 
in estimating the degree of emission reduction achieved by best-
performing sources, and in setting MACT floors (see Mossville 
Environmental Action Now v. EPA, 370 F.3d 1232, 1241-42 (D.C. Cir. 
2004)).
    To account for variability in the operation and emissions, we used 
the stack test data to calculate the average emissions and the 99-
percent upper prediction limit (UPL) to derive the MACT floor limit. 
For more information regarding the general use of the UPL and why it is 
appropriate for calculating MACT floors, see the memorandum, ``Use of 
the Upper Prediction Limit for Calculating MACT Floors,'' which is 
available in the docket for this action. Table 3 of this preamble 
provides the results of the MACT floor calculations (considering 
variability) for Hg.

    Table 3--Results of the MACT Floor Calculations for Mercury From
         Phosphate Rock Calciners at Phosphoric Acid Facilities
------------------------------------------------------------------------
             Pollutant                  Results            Units
------------------------------------------------------------------------
Hg                                      0.14 \a\   mg/dscm @3%O2.
------------------------------------------------------------------------
\a\ The EPA is proposing beyond-the-floor emission standards for Hg from
  phosphate rock calciners; therefore, the results of the MACT floor
  variability calculations do not reflect the proposed emission
  standards for Hg from phosphate rock calciners. Please refer to Table
  4 of this preamble for the proposed emission limits for Hg.

    Additional details regarding the MACT floor analysis and UPL 
calculations, including a description of how we assessed the limited 
dataset that was used to calculate the MACT floor value, are contained 
in the memorandum, ``Maximum Achievable Control Technology (MACT) Floor 
Analysis for the Phosphate Rock Calciners at Phosphoric Acid 
Manufacturing Plants,'' which is available in the docket for this 
action. Additional detail on the EPA's approach for applying the UPL 
methodology to limited datasets is provided in the memorandum, 
``Approach for Applying the Upper Prediction Limit to Limited 
Datasets,'' which is available in the docket for this action.
    Once the MACT floor determinations were completed, we considered 
various regulatory options more stringent than the MACT floor levels of 
control (e.g., control technologies or work practices that could result 
in lower emissions). The memorandum, ``Beyond-the-Floor Analysis for 
Phosphate Rock Calciners at Phosphoric Acid Manufacturing Plants,'' 
which is available in the docket for this action, contains a detailed 
description of the beyond-the-floor consideration. We first identified 
regulatory requirements for phosphate rock calciners that would be more 
stringent than the MACT floor level of control and determined whether 
the requirements were technically feasible. If the more stringent 
requirements were technically feasible, we conducted an analysis of the 
cost and emission impacts associated with implementing the 
requirements.
    We analyzed a beyond-the-floor option of requiring existing 
phosphate rock calciners to meet a Hg emission limit of 0.014 
milligrams per dry standard cubic meter (mg/dscm) on a 3-percent oxygen 
basis. This reflects the expected emission reductions that can be 
achieved using the available control technologies. Specifically, we 
analyzed

[[Page 66534]]

the costs and emission reductions of two types of control technologies: 
installation of a fixed-bed carbon adsorption system, and installation 
of activated carbon injection (ACI) (followed by either the existing 
wet electrostatic precipitators (WESP) or a newly installed fabric 
filter system). Both the fixed-bed and ACI systems are estimated to 
reduce emissions of Hg by 90 percent from the baseline emissions (for 
further detail see the memorandum, ``Beyond-the-Floor Analysis for the 
Phosphate Rock Calciners at Phosphoric Acid Manufacturing Plants,'' 
which is available in the docket for this action). We chose to evaluate 
an ACI system (installed after the existing WESP) followed by a fabric 
filter, in addition to an ACI system followed by the existing WESP, due 
to the relatively high moisture content of the calciner exhaust 
streams. ACI followed by a fabric filter is the most common control 
system installed for control of Hg, but in this case, the high moisture 
content may have a tendency to blind a fabric filter.
    We also evaluated fixed-bed carbon adsorption systems as potential 
control technology for achieving beyond-the-floor emission reductions. 
For a fixed-bed carbon adsorption system, we estimate that applying 
additional control to reduce Hg emissions from phosphate rock calciners 
would result in an annualized cost of approximately $1.2 million, and 
would achieve Hg reductions of 145 pounds of Hg per year. The cost 
effectiveness of installing a fixed-bed carbon adsorber was estimated 
to be $8,000 dollars per pound of Hg reduced, which we considered to be 
cost effective. This cost-effectiveness for Hg is comparable to or less 
than values the EPA found to be cost effective for removal of Hg in 
other air toxics rules. For example, in the National Emission Standards 
for Hazardous Air Pollutants: Mercury Emissions from Mercury Cell 
Chlor-Alkali Plants, the cost effectiveness was found to be between 
$13,000 to $31,000 per pound of Hg emissions reduced for the individual 
facilities (see Supplemental proposed rule, 76 FR 13858 (March 14, 
2011)).
    For an ACI system, we estimate that applying additional control to 
reduce Hg emissions from phosphate rock calciners would result in an 
annualized cost of approximately $1.8 million to $2.5 million (using a 
WESP or a fabric filter system, respectively), and would achieve Hg 
reductions of 145 pounds of Hg per year. The cost effectiveness of 
installing an ACI system was estimated to be between $12,000 and 
$17,000 dollars per pound of Hg reduced (using a WESP or a fabric 
filter system, respectively), which we considered to be cost effective 
on the basis previously stated. Consequently, we are proposing that 
existing phosphate rock calciners meet a Hg emission limit of 0.014 mg/
dscm on a 3-percent oxygen basis as a beyond-the-floor standard. We are 
also proposing that phosphate rock calciners at new sources meet a 
beyond-the-floor Hg emission limit of 0.014 mg/dscm on a 3-percent 
oxygen basis. Table 4 of this preamble lists the proposed Hg emission 
limits for phosphate rock calciners. We are unaware of any technologies 
that could further reduce Hg emissions from streams that have high 
moisture content. The memorandum, ``Beyond-the-Floor Analysis for the 
Phosphate Rock Calciners at Phosphoric Acid Manufacturing Plants,'' 
which is available in the docket for this action, documents the results 
of the beyond-the-floor analysis.

    Table 4--Proposed Emission Limits for Mercury from Phosphate Rock
                 Calciners at Phosphoric Acid Facilities
------------------------------------------------------------------------
             Pollutant                   Limit             Units
------------------------------------------------------------------------
Existing and new sources:
Hg.................................        0.014   mg/dscm @3%O2.
------------------------------------------------------------------------

b. Determination of Work Practice Standards for Hydrogen Fluoride From 
Phosphate Rock Calciners
    The 1999 Phosphoric Acid Manufacturing NESHAP (i.e., NESHAP subpart 
AA) included emissions limits for total F as a surrogate for HF for 
WPPA and SPA processes. A total F emission limit was not set for 
phosphate rock dryers or phosphate rock calciners. We propose to 
address the failure to set an emission limit in this action. Test data 
collected from industry in 2014 show HF emissions from phosphate rock 
calciners, although more than half of the data are below-the-method 
detection limit (BDL). CAA section 112(h)(1) states that the 
Administrator may prescribe a work practice standard or other 
requirements, consistent with the provisions of CAA sections 112(d) or 
(f), in those cases where, in the judgment of the Administrator, it is 
not feasible to enforce an emission standard. CAA section 112(h)(2)(B) 
further defines the term ``not feasible'' in this context to apply when 
``the application of measurement technology to a particular class of 
sources is not practicable due to technological and economic 
limitations.'' Therefore, we are proposing work practice standards for 
HF emissions from phosphate rock calciners. Rock dryers are no longer 
used in this source category. Therefore, we are not proposing a limit 
or work practice standard for HF from rock dryers.
    In response to a January 2014 CAA section 114 request, the EPA 
received HF emissions testing results by EPA Method 320 for one 
phosphate rock calciner. Of the six test runs reported to EPA, four 
were reported as BDL. The detected concentrations were, on average, 
only 20 percent above the method detection limit. The expected 
measurement imprecision for an emissions value occurring at or near the 
method detection limit is about 40 to 50 percent. Because the HF 
emission levels are BDL or near BDL, the measured concentration values 
are questionable for HF. As a result, we are uncertain of the true 
levels of HF emitted from phosphate rock calciners.
    Because approximately 67 percent of the HF data collected using EPA 
Method 320 were BDL, and the fact that the detected concentrations 
were, on average, only 20 percent above the method detection limit, the 
EPA concludes that HF emissions from phosphate rock calciners cannot 
practicably be measured. As a result, we are proposing work practice 
standards in place of a numeric emission limit for HF from phosphate 
rock calciners.
    According to information provided by industry, phosphate rock 
calciners are operated to remove organic content from the phosphate 
rock in efforts to produce products with low organic content (refer to 
the memorandum, ``Summary of August 14, 2012 U.S. EPA Meeting with PCS 
Phosphate,'' which is available in the docket for this action). Based 
on review of available literature, liberation of fluorine takes place 
at temperatures between approximately 2,500 and 2,750 degrees 
Fahrenheit (in addition to adding defluorinating agents), whereas

[[Page 66535]]

removal of organic matter and dissociation of carbonates is typically 
carried out between 1,200 and 1,830 degrees Fahrenheit. Process flow 
diagrams submitted by industry in response to an April 2010 and January 
2014 CAA section 114 request indicate that the phosphate rock calciners 
currently in operation maintain a calcination temperature of less than 
1,600 degrees Fahrenheit. Based on this information, we conclude that 
maintaining the temperature of the phosphate rock calciner fluidized 
bed at less than 1,600 degrees Fahrenheit will minimize emission of HF. 
Therefore, we are proposing a maximum calcination temperature of less 
than 1,600 degrees Fahrenheit for phosphate rock calciners as a work 
practice standard to control HF emissions. The facility that operates 
calciners currently maintains temperatures below 1,600 degrees 
Fahrenheit, as such, we do not expect any costs of control with this 
proposed work practice requirement.
    In addition, particulate emissions from the calciners currently in 
operation are controlled using a combination of an absorber (i.e., a 
Venturi-type wet scrubbing system) and an electrostatic precipitator. 
As discussed in section IV.D.1 of this preamble, the Phosphoric Acid 
Manufacturing source category uses wet scrubbing technology (including 
Venturi-type wet scrubbing systems) to control HF emissions from 
various processes located at the source category. Because HF is highly 
soluble in water, we expect that, if HF is present in the calcination 
exhaust stream in any amount, the absorbers currently in operation are 
achieving some level of emission reduction. As a result, we are 
proposing to require that emissions from phosphate rock calciners be 
routed to an absorber, in addition to proposing a maximum calcination 
temperature, to limit emissions of HF from phosphate rock calciners.
    Refer to the memorandum, ``Maximum Achievable Control Technology 
(MACT) Floor Analysis for the Phosphate Rock Calciners at Phosphoric 
Acid Manufacturing Plants,'' available in the docket for this action, 
for additional information regarding the determination of the work 
practice standards to control HF emissions. The EPA did not identify 
any beyond-the-floor options for reducing HF emissions from the 
phosphate rock calciners other than the proposed work practice 
standard.
2. Gypsum Dewatering Stack and Cooling Pond Work Practices
    We conducted an evaluation of fugitive HF emissions from gypsum 
dewatering stacks and cooling ponds and determined that these fugitive 
sources contribute the majority of HF emissions from phosphoric acid 
facilities (see the memorandum, ``Emissions Data Used in Residual Risk 
Modeling: Phosphoric Acid and Phosphate Fertilizer Production Source 
Categories,'' which is available in the docket). The 1999 Phosphoric 
Acid Manufacturing NESHAP (i.e., NESHAP subpart AA) did not include 
emission limits or require work practices for control of fugitive HF 
emissions from gypsum dewatering stacks, or cooling ponds. We are 
proposing standards that will control HAP emissions from gypsum 
dewatering stacks and cooling ponds. We are proposing work practices 
instead of numeric emission limits because it is ``not feasible to 
prescribe or enforce an emission standard'' for these emissions because 
they are not ``emitted through a conveyance designed and constructed to 
emit or capture such pollutant'' (see CAA section 112(h)(2)(A)) as the 
several hundred acres average size of these sources makes conveyance 
impractical. The work practices would apply to any existing or new 
gypsum dewatering stacks or cooling ponds at a source subject to this 
subpart.
    A review of state requirements for regulated facilities and current 
literature on the industry revealed work practices that include 
submerging the discharge pipe below the surface of the cooling pond; 
wetting the gypsum dewatering stack areas during hot or dry periods to 
minimize dust formation; using rim ditch (cell) building techniques 
that minimize the overall surface area of the gypsum dewatering stack 
and pond; applying slaked lime to the gypsum dewatering stack surfaces; 
and applying soil caps and vegetation to inactive gypsum dewatering 
stacks. After review of these various state requirements, the EPA 
believes that the control measures required by the states for these 
facilities are effective in reducing fugitive emissions. These measures 
are, therefore, consistent with CAA section 112(d) controls and reflect 
a level of performance analogous to a MACT floor. See CAA section 
112(h)(1) (in promulgating work practices, the EPA is to adopt 
standards ``which in the Administrator's judgment [are] consistent with 
section (d) or (f) of this section'').
    We are proposing that facilities develop a site-specific gypsum 
dewatering stack and cooling pond management plan to control fugitive 
emissions. We have developed a list of control techniques for 
facilities to use in development of this management plan. These 
techniques include: introducing cooling water or gypsum slurry into a 
pond below the surface in order to minimize aeration of F in the water; 
wetting the active gypsum dewatering stack areas during hot or dry 
periods to minimize dust formation; using cell building techniques that 
minimize the overall surface area of the active gypsum dewatering 
stack; applying slaked lime to the active gypsum dewatering stack 
surfaces; and applying soil caps and vegetation to all side slopes of 
the active gypsum dewatering stack up to 50 feet below the stack top. 
The memorandum, ``Analysis of Requirements for Gypsum Dewatering Stacks 
and Cooling Ponds at Phosphoric Acid Manufacturing Plants,'' which is 
available in the docket, provides more detail for choosing these 
control measures.
    The varying geographic locations of facilities influence the 
composition of the phosphate ore mined and the ambient meteorological 
conditions, both of which will influence best management practices. 
Therefore, we believe that it is most effective for sources to 
determine the best practices that are to be incorporated into their 
site-specific management plan. However, as previously noted, sources 
would be required to incorporate management practices from the list of 
options being proposed.
    We are also proposing a work practice applicable to facilities when 
new gypsum dewatering stacks are constructed that would limit the size 
of active gypsum dewatering stacks and control fugitive emissions. When 
new gypsum dewatering stacks are constructed, the ratio of total active 
gypsum dewatering stacks area (i.e., sum of the footprint acreage of 
all existing and new active gypsum dewatering stacks combined) to 
annual phosphoric acid manufacturing capacity must not be greater than 
80 acres per 100,000 tons of annual phosphoric acid manufacturing 
capacity (equivalent P2O5 feed).
    The extensive area that gypsum dewatering stacks encompass is a 
direct correlation to their high HF emissions. This is seen when 
estimating emissions from gypsum dewatering stacks, where emission 
factors are applied (tons HF per acre per year). In addition, gypsum 
dewatering stacks are continuously releasing emissions unless they are 
properly covered and closed. Limiting the size of gypsum dewatering 
stacks would minimize emissions by creating an upper bound on 
emissions; this would require appropriate foresight and planning of the 
new gypsum dewatering stack construction process to ensure the gypsum 
dewatering stack area to

[[Page 66536]]

manufacturing capacity ratio is not exceeded (i.e., facilities may need 
to close gypsum dewatering stacks to comply). While certain states 
already require the closure of gypsum dewatering stacks at the end of 
their life, this work practice would apply to facilities in all states 
and would ensure that gypsum dewatering stacks are appropriately 
considered from an emissions perspective in all phases of their life.
    To develop the limit of 80 acres per 100,000 tons of annual 
phosphoric acid manufacturing capacity, we evaluated the area of active 
gypsum dewatering stacks to manufacturing capacity for each facility. 
We expected facilities with greater manufacturing capacities to, in 
most cases, require larger gypsum dewatering stack areas, because 
higher acid manufacturing rates result in higher gypsum generation 
rates; however, this was not the case. Based on the available data, we 
did not detect a correlation between gypsum stack dewatering area and 
phosphoric acid manufacturing capacity.
    We considered that the size of active gypsum dewatering stacks at a 
facility is dynamic and does not remain the same over time. We also 
considered other factors that influence gypsum dewatering stack size 
such as the actual area available for stack construction, closure of 
recently active stacks, and local permitting limitations. Gypsum 
dewatering stacks also serve the fertilizer manufacturing processes in 
addition to the phosphoric acid manufacturing processes as a source of 
cooling water, wash water, process water and slurry water. As a result, 
we concluded that the size of gypsum dewatering stacks is a function of 
several factors, including process optimization. Nonetheless, we still 
believe that phosphoric acid manufacturing capacity has a significant 
impact on the size of gypsum dewatering stacks. As a result, we are 
proposing a size limit based on the current operation of 10 out of 12 
facilities. We believe this upper limit captures the complexities of 
gypsum dewatering stack size determination, but provides a reasonable 
limit on the size of active stacks in the future.
    Further discussion on the site-specific gypsum dewatering stack and 
cooling pond management plan and details on the calculation of the 
ratio of gypsum dewatering stack area to phosphoric acid manufacturing 
capacity is provided in the memorandum, ``Analysis of Requirements for 
Gypsum Dewatering Stacks and Cooling Ponds at Phosphoric Acid 
Manufacturing Plants,'' which is available in the docket for this 
action. We solicit comment on the proposed site-specific gypsum 
dewatering stack and cooling pond management plan. We are also seeking 
comment on other approaches for minimizing fugitive emissions from 
gypsum dewatering stacks including, but not limited to: Limiting the 
size of active gypsum dewatering stacks independent of phosphoric acid 
manufacturing capacity, and requiring owners or operators to apply soil 
caps and vegetation to all side slopes (up to a certain distance below 
the stack top) for all new active gypsum dewatering stacks and new 
gypsum cells that are built on to (or adjacent to) existing active 
gypsum dewatering stacks.

B. What are the results of the risk assessment and analyses for the 
Phosphoric Acid Manufacturing source category?

    The preamble sections below summarize the results of the risk 
assessment for the Phosphoric Acid Manufacturing source category. The 
complete risk assessment, Draft Residual Risk Assessment for Phosphate 
Fertilizer Production and Phosphoric Acid Manufacturing, is available 
in the docket for this action.
1. Inhalation Risk Assessment Results
    The basic chronic inhalation risk estimates presented here are the 
maximum individual lifetime cancer risk, the maximum chronic HI and the 
cancer incidence. We also present results from our acute inhalation 
impact screening in the form of maximum HQs, as well as the results of 
our preliminary screening for potential non-inhalation risks from PB-
HAP. Also presented are the HAP ``drivers,'' which are the HAP that 
collectively contribute 90 percent of the maximum cancer risk or 
maximum HI at the highest exposure location.
    The inhalation risk results for this source category indicate that 
maximum lifetime individual cancer risks are less than 1-in-1 million. 
The total estimated cancer incidence from this source category is 
0.0002 excess cancer cases per year, or one excess case in every 5,000 
years. The maximum chronic non-cancer TOSHI value for the source 
category could be up to 0.2 associated with emissions of hydrofluoric 
acid from gypsum dewatering stacks and cooling ponds, indicating no 
significant potential for chronic non-cancer impacts.
    We analyzed the potential differences between actual emissions 
levels and calculated the maximum emissions allowable under the MACT 
standards for every emission process group for this source category. 
Based upon the above analysis, we multiplied the modeled actual risks 
for the MIR facility with site-specific process multipliers to estimate 
allowable risks under the MACT. We deemed this approach sufficient due 
to the low actual modeled risks for the source category. The maximum 
lifetime individual cancer risks based upon allowable emissions are 
still less than 1-in-1 million. The maximum chronic non-cancer TOSHI 
value increased to an HI of 0.3.
2. Acute Risk Results
    Worst-case acute HQs were calculated for every HAP that has an 
acute benchmark. Two facilities were identified with HQ values greater 
than 1. For cases where the acute HQ from the screening analysis was 
greater than 1, we further refined the estimates by determining the 
highest HQ value that is outside facility boundaries. The highest 
refined, worst-case acute HQ value is 2 (based on the acute reference 
exposure level (REL) for hydrofluoric acid). The HQ values represent 
upper-bound risk estimates for both facilities; the off-site locations 
for these sites were either located in a rural location in which public 
access is limited or in an off-site area that may be owned by the 
facility. The primary source of emissions is fugitive air releases from 
gypsum dewatering stacks and cooling ponds. See the memorandum, 
``Emissions Data Used in Residual Risk Modeling: Phosphoric Acid and 
Phosphate Fertilizer Production Source Category,'' which is available 
in the docket for this rulemaking, for a detailed description of the 
methodology we used to develop the maximum hourly emissions for this 
source category. Based on maximum hourly emission estimates available 
by emission process group, an emissions multiplier of 1 was used to 
estimate the peak hourly emission rates for this source category.
    To better characterize the potential health risks associated with 
estimated worst-case acute exposures to HAP, we examined a wider range 
of available acute health metrics than we examine for our chronic risk 
assessments. This is in response to the acknowledgement that there are 
generally more data gaps and inconsistencies in acute reference values 
than there are in chronic reference values. By definition, the acute 
reference exposure level relied on in the analysis, the California 
Reference Exposure Level (CA-REL), represents a health-protective level 
of exposure, with no risk anticipated below those levels, even for 
repeated exposures; however, the health risk from higher-level 
exposures is unknown. Therefore, when

[[Page 66537]]

an REL is exceeded, we have used secondary acute dose-response exposure 
levels, including the AEGL-1 and ERPG, as a second comparative measure. 
The worst-case, maximum estimated 1-hour exposure to hydrofluoric acid 
outside the facility fence line for the Phosphoric Acid Manufacturing 
source category is 0.5 ug/m\3\. This estimated worst-case exposure 
exceeds the 1-hour REL by a factor of 2 (HQREL = 2) and is 
below the 1-hour AEGL-1 (HQAEGL-1 = 0.6). See the 
memorandum, ``Draft Residual Risk Assessment for Phosphate Fertilizer 
Production and Phosphoric Acid Manufacturing'' in the docket for this 
rulemaking for additional information.
3. Multipathway Risk Screening Results
    For the Phosphoric Acid Production source category, the EPA 
conducted a Tier I screening-level evaluation of the potential human 
health risks associated with emissions of PB-HAP. The PB-HAP emitted by 
facilities in this category include Hg compounds (12 facilities), Pb 
compounds (12 facilities), and cadmium compounds (12 facilities), 
dioxin/furan compounds (1 facility), and POM compounds (1 facility). We 
compared reported emissions of PB-HAP to the Tier I screening emission 
thresholds established by the EPA for the purposes of the RTR risk 
assessments. One facility emitted divalent Hg (Hg\2+\) above the Tier I 
screening threshold level, exceeding the screening threshold by a 
factor of 7 and the cadmium emissions exceeded the cadmium screening 
threshold by a factor of 2. Consequently, we conducted a Tier II 
screening assessment.
    For the Tier II screening assessment, we refined our Hg\2+\ and 
cadmium analysis with additional site-specific information. The 
additional site-specific information included the land use around the 
facilities, the location of fishable lakes within 50 km of the 
facility, and local wind direction and speed. The Tier II Screen also 
included two scenarios to evaluate health risks by evaluating risks 
separately for two hypothetical receptors; (1) subsistence travelling 
angler and (2) subsistence farmer. The travelling fisher scenario is 
based on the idea that an adult fisher might travel to multiple lakes 
if the first (i.e., highest-concentration) lake is unable to provide 
him an adequate catch to satisfy the assumed ingestion rate (i.e., 373 
grams/day for adults) over a 70-year time frame. This assessment uses 
the assumption that the biological productivity limitation of each lake 
is 1 gram of fish per acre of water, meaning that in order to fulfill 
the adult ingestion rate, the fisher will need to fish from 373 total 
acres of lakes. The result of this analysis was the development of a 
site-specific emission-screening threshold for Hg\2+\. We compared this 
refined Tier II screening threshold for Hg\2+\ to the facility's Hg\2+\ 
emissions. The facility's emissions from both pollutants of concern are 
below the Tier II screening threshold, indicating no potential for 
multipathway impacts of concern from this facility.
    For the other PB-HAP emitted by facilities in the source category, 
no facilities emit POM, or dioxin compounds above the Tier I screening 
threshold level. Pb is a PB-HAP, but the NAAQS value (which was used 
for the chronic noncancer risk assessment) takes into account 
multipathway exposures, so a separate multipathway screening value was 
not developed. Since we did not estimate any exceedances of the NAAQS 
in our chronic noncancer risk assessment, we do not expect any 
significant multipathway exposure and risk due to Pb emissions from 
these facilities. For more information on the multipathway screening 
assessment conducted for this source category, see the memorandum, 
``Draft Residual Risk Assessment for Phosphate Fertilizer Production 
and Phosphoric Acid Manufacturing'' provided in the docket for this 
rulemaking.
4. Environmental Risk Screening Results
    As described in section III.A.5 of this preamble, we conducted an 
environmental risk screening assessment for the Phosphoric Acid 
Manufacturing source category. In the Tier I screening analysis for PB-
HAP other than Pb (which was evaluated differently, as noted in section 
III.A.5 of this preamble), none of the individual modeled 
concentrations for any facility in the source category exceed any of 
the ecological benchmarks (either the LOAEL or NOAEL). Therefore, we 
did not conduct a Tier II screening assessment. For Pb, we did not 
estimate any exceedances of the secondary Pb NAAQS.
    For acid gases, the average modeled concentration around each 
facility (i.e., the average concentration of all off-site data points 
in the modeling domain) did not exceed any ecological benchmarks 
(either the LOAEL or NOAEL). For HCl, each individual concentration 
(i.e., each off-site data point in the modeling domain) was below the 
ecological benchmarks for all facilities. For HF, less than 1 percent 
of the off-site modeling domain for the source category was above the 
LOAEL ecological benchmark. The largest facility exceedance area 
represented 3 percent of the facility's 50 km modeling domain. We did 
not identify an adverse environmental effect as defined in CAA section 
112(a)(7) from HAP emissions from this source category.
5. Facility-Wide Risk Results
    The facility-wide MIR and TOSHI are based on emissions, as 
identified in the NEI, from all emissions sources at the identified 
facilities. The results of the facility-wide analysis indicate that all 
12 facilities with phosphoric acid manufacturing processes have a 
facility-wide cancer MIR less than or equal to 1-in-1 million. The 
maximum facility-wide TOSHI for the source category is 0.2. The risk 
results are summarized in Table 5 of this preamble.

                                         Table 5--Human Health Risk Assessment for Phosphoric Acid Manufacturing
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Cancer MIR (in 1                                              Max chronic non-cancer
                                              million)             Cancer     Population   Population             HI
  Category & number  of facilities   --------------------------  incidence    with risks   with risks --------------------------   Worst-case max acute
               modeled                  Based on     Based on    (cases per   of 1-in-1    of 10-in-1    Based on     Based on        non-cancer HQ
                                         actual     allowable      year)      million or   million or     actual     allowable
                                       emissions    emissions                    more         more      emissions    emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Phosphoric Acid (12 facilities).....         0.09         0.09       0.0002            0            0          0.2          0.3  HQREL = 2 (hydrofluoric
                                                                                                                                  acid)
                                      ...........  ...........  ...........  ...........  ...........  ...........  ...........  HQAEGL-1 = 0.6
                                                                                                                                  (hydrofluoric acid).

[[Page 66538]]

 
Facility-wide (12 facilities).......          0.5          0.5        0.001            0            0          0.2          0.3  --
--------------------------------------------------------------------------------------------------------------------------------------------------------

6. What demographic groups might benefit from this regulation?
    To determine whether or not to conduct a demographics analysis, 
which is an assessment of risks to individual demographic groups, we 
look at a combination of factors including the MIR, non-cancer TOSHI, 
population around the facilities in the source category and other 
relevant factors. For the Phosphoric Acid Manufacturing source 
category, the MIR is less than 1-in-1 million and the HI is less than 
1. Therefore, we did not conduct an assessment of risks to individual 
demographic groups for this rulemaking. However, we did conduct a 
proximity analysis, which identifies any overrepresentation of 
minority, low income or indigenous populations near facilities in the 
source category. The results of this analysis are presented in the 
section of this preamble titled, ``Executive Order 12898: Federal 
Actions to Address Environmental Justice in Minority Populations and 
Low-Income Populations.''

C. What are our proposed decisions regarding risk acceptability, ample 
margin of safety and adverse environmental effects for the Phosphoric 
Acid Manufacturing source category?

1. Risk Acceptability
    The risk assessment results for the phosphoric acid manufacturing 
source category indicate that all facilities have a cancer MIR less 
than 1-in-1 million. The maximum TOSHI is less than 1, and the maximum 
worst-case acute HQ is less than the AEGL-1 benchmark. Therefore, we 
propose that the risks posed by emissions from this source category are 
acceptable.
2. Ample Margin of Safety Analysis and Proposed Controls
    Under the ample margin of safety analysis, we evaluate the cost and 
feasibility of available control technologies and other measures 
(including the controls, measures, and costs evaluated under the 
technology review) that could be applied in this source category to 
further reduce the risks due to emissions of HAP identified in our risk 
assessment, as well as the health impacts of such potential additional 
measures. As noted in our discussion of the technology review in 
section III.C of this preamble, no measures (beyond those already in 
place or that we are proposing today under CAA sections 112(d)(2) and 
(d)(3)) were identified for reducing HAP emissions from the Phosphoric 
Acid Manufacturing source category. In addition, because our analyses 
show that the maximum baseline chronic cancer risk is below 1-in-1 
million, the maximum chronic non-cancer HI is less than 1, and the 
worst-case acute HQ is less than the AEGL-1, minimal reductions in risk 
could be achieved even if we identified measures that could reduce HAP 
emissions further. Based on the discussion above, we propose that the 
current standards provide an ample margin of safety to protect public 
health.
    Although the current standards were found to provide an ample 
margin of safety to protect public health, we also are proposing 
additional standards to address previously unregulated emissions of Hg 
and HF from phosphate rock calciners. We are proposing Hg emission 
limits and HF work practice standards for the phosphate rock calciners 
at phosphoric acid facilities, resulting in an estimated HAP reduction 
between 165 and 220 pounds per year of Hg. We are also proposing that 
sources develop management plans for fugitive emissions from cooling 
ponds and gypsum dewatering stacks. As noted above, we are proposing 
that the MACT standard, prior to the implementation of the proposed 
emission limits and work practice standards for phosphate rock 
calciners discussed in this section of the preamble and the fugitive 
emissions work practice standard, provides an ample margin of safety to 
protect public health. Therefore, we maintain that, after the 
implementation of the phosphate rock calciner emission limits and work 
practice standards, and the fugitive emissions work practice standard, 
the rule will continue to provide an ample margin of safety to protect 
public health. Consequently, we do not believe it will be necessary to 
conduct another residual risk review under CAA section 112(f) for this 
source category 8 years following promulgation of new emission limits 
and work practice standards for phosphate rock calciners and 
promulgation of new fugitive emission work practices, merely due to the 
addition of these MACT requirements. While our decisions on risk 
acceptability and ample margin of safety are supported even in the 
absence of these reductions (from calciners, cooling ponds and gypsum 
dewatering stacks), if we finalize the proposed requirements for these 
sources, they would further strengthen our conclusions that risk is 
acceptable with an ample margin of safety to protect public health.
    Although we did not identify any new technologies to reduce risk 
from this source category, we are specifically requesting comment on 
whether there are additional control measures that may be able to 
reduce risks from the source category. We request any information on 
potential emission reductions of such measures, as well the cost and 
health impacts of such reductions to the extent they are known.
3. Adverse Environmental Effects
    Based on the results of our environmental risk screening 
assessment, we conclude that there is not an adverse environmental 
effect as a result of HAP emissions from the Phosphoric Acid 
Manufacturing source category. We are proposing that it is not 
necessary to set a more stringent standard to prevent, taking into 
consideration costs, energy, safety and other relevant factors, an 
adverse environmental effect.

D. What are the results and proposed decisions based on our technology 
review for the Phosphoric Acid Manufacturing source category?

1. NESHAP Technology Review
    In order to fulfill our obligations under CAA section 112(d)(6), we 
conducted a technology review to identify new developments that may

[[Page 66539]]

advise revisions to the current NESHAP standards applicable to the 
Phosphoric Acid Manufacturing source category (i.e., NESHAP subpart 
AA). In conducting our technology review for the Phosphoric Acid 
Manufacturing source category, we utilized the RBLC database and the 
data submitted by facilities in response to the April 2010 CAA section 
114 request.
    Based on our review of the RBLC, we did not find any new 
developments in practices, processes and control technologies that have 
been applied since the original NESHAP to reduce emissions from 
phosphoric acid manufacturing plants.
    Based on our review of the CAA section 114 data (see memorandum, 
``CAA Section 111(b)(1)(B) and 112(d)(6) Reviews for the Phosphoric 
Acid Manufacturing and Phosphate Fertilizer Production Source 
Categories,'' which is available in Docket No. EPA-HQ-OAR-2012-0522), 
we determined that the control technologies used to control stack 
emissions at phosphoric acid manufacturing plants have not changed 
since the EPA published the 1996 memorandum, ``National Emission 
Standards for Hazardous Air Pollutants from Phosphoric Acid 
Manufacturing and Phosphate Fertilizers Production; Proposed Rules--
Draft Technical Support Document and Additional Technical 
Information,'' which is available in Docket ID No. A-94-02.
    In general, the Phosphoric Acid Manufacturing source category 
continues to use wet scrubbing technology to control HF emissions from 
the various processes located at this source category (e.g., WPPA, SPA 
and PPA). We did not identify any technical developments in wet 
scrubbing methods used at phosphoric acid manufacturing plants. As 
noted in the 1996 memorandum discussed above, the type and 
configuration of the wet scrubbing technology varies significantly 
between facilities and between process lines within a facility. In 
addition, electrostatic precipitators have been installed to control PM 
emissions at the phosphate rock calciners. In order to determine the 
differences in effectiveness of control technologies we identified, we 
reviewed the emissions data submitted by facilities in response to the 
April 2010 and January 2014 CAA section 114 requests.
    For WPPA process lines, differences in facility emissions may be 
related to the control technology used; however, it is difficult to 
discern whether this is the case because each WPPA process line 
operates a unique equipment and control technology configuration (i.e., 
there are no WPPA process lines that operate in similar configurations 
for comparison).
    We observed some differences in total F emissions from SPA process 
lines. However, we did not find any patterns in emissions reductions 
based on control technology used because most of the SPA process lines 
that were tested operate a unique equipment and control technology 
configuration. For all SPA process lines that we examined, emissions 
from the evaporators are sent to a single wet scrubber, but the type of 
wet scrubber used at these SPA process lines varies.
    Some SPA process lines include an oxidation step to remove organic 
impurities from the acid. For one facility, we noted relatively high HF 
emissions from a currently uncontrolled oxidation process. The 
application of wet scrubbing control technology would be consistent 
with other SPA process lines, where all applicable emission points are 
controlled by wet scrubbers. Available information from similar sources 
controlled by wet scrubbers indicates that the use of wet scrubbing 
control technology would result in a reduction of emissions from the 
identified oxidation process to levels consistent with other industry 
wide SPA emissions. Because the facility already has wet scrubbing 
technology for their SPA process line, they should only need to install 
additional ductwork from the uncontrolled emission point to the wet 
scrubber. Therefore, it would not be necessary to install a new wet 
scrubber to control the oxidation process emissions. Refer to the 
memorandum, ``Control Costs and Emissions Reductions for Phosphoric 
Acid and Phosphate Fertilizer Production Source Categories,'' which is 
available in the docket, for additional discussion regarding the 
uncontrolled oxidation process.
    For PPA process lines, it is not possible to discern whether the 
control technology used is more (or less) effective than another 
control technology because there is only one set of data.
    We believe that observed differences in HAP emissions from WPPA, 
SPA and PPA process lines, except for the one uncontrolled oxidation 
process at a SPA process line, are the result of factors other than 
control technology (e.g., subtle differences in sampling and analytical 
techniques, age of control equipment and differences in facility 
operating parameters). Therefore, neither these data nor any other 
information we have examined show that there has been a significant 
improvement in the add-on control technology or other equipment since 
promulgation of NESHAP subpart AA.
    There are six existing phosphate rock calciners located at one 
facility. These are the only phosphate rock calciners in the source 
category. The one facility with calciners had wet scrubbers installed 
prior to the current NESHP PM limits being promulgated. To meet the 
current PM limits, the facility added WESP in addition to the 
previously installed wet scrubbers. Based on the data submitted by 
facilities in response to the April 2010 CAA section 114 request, PM 
emissions from these units vary from 0.0012 to 0.0695 grains PM per dry 
standard cubic foot. This range of emissions indicate that the current 
limits represent expected performance of the control technology 
configuration. We did not identify any new cost-effective technologies 
that could reduce emissions further from this source. Based on this 
information, we are not proposing any revisions to the PM limits from 
calciners.
    We also reviewed the CAA section 114 responses to identify any work 
practices, pollution prevention techniques and process changes at 
phosphoric acid manufacturing plants that could achieve emission 
reductions. We did not identify any developments regarding practices, 
techniques, or process changes that affect point source emissions from 
this source category. See the memorandum, ``CAA Section 111(b)(1)(B) 
and 112(d)(6) Reviews for the Phosphoric Acid Manufacturing and 
Phosphate Fertilizer Production Source Categories,'' which is available 
in the docket, for additional details on the technology review.
    In light of the results of the technology review, we conclude that 
additional standards are not necessary pursuant to CAA section 
112(d)(6) and we are not proposing changes to NESHAP subpart AA as part 
of our technology review. We solicit comment on our proposed decision.
2. NSPS Review
    Pursuant to CAA section 111(b)(1)(B), we conducted a review to 
identify new developments that may advise revisions to the current NSPS 
standards applicable to the Phosphoric Acid Manufacturing source 
category (i.e., NSPS subparts T and U). This review considered both (1) 
whether developments in technology or other factors support the 
conclusion that a different system of emissions reduction has become 
the ``best system of emissions reduction'' and (2) whether emissions 
limitations and percent reductions beyond those required by the 
standards are achieved in practice.

[[Page 66540]]

    As discussed in section IV.D.1 of this preamble, the EPA conducted 
a thorough search of the RBLC, section 114 data received from industry 
and other relevant sources. The emission sources for both NSPS and the 
control technologies that would be employed are the same as those used 
for the NESHAP regulating phosphoric acid plants, yielding the same 
results of no cost-effective emission reductions strategies being 
identified.
    Therefore, we are proposing that revisions to NSPS subpart T and 
subpart U standards are not appropriate pursuant to CAA section 
111(b)(1)(B). We solicit comment on our proposed determination.

E. What other actions are we proposing for the Phosphoric Acid 
Manufacturing source category?

    In addition to the proposed actions described above, we are 
proposing additional revisions or clarifications. We are proposing 
clarifications to the applicability of NESHAP subpart AA, NSPS subpart 
T, and NSPS subpart U. In addition, we are proposing revisions to the 
startup, shutdown and malfunction (SSM) provisions of NESHAP subpart AA 
in order to ensure that they are consistent with the court decision in 
Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008), which vacated two 
provisions that exempted sources from the requirement to comply with 
otherwise applicable CAA section 112(d) emission standards during 
periods of SSM. We also are proposing various other changes to testing, 
monitoring, recordkeeping and reporting requirements in NESHAP subpart 
AA, NSPS subpart T, and NSPS subpart U. Our analyses and proposed 
changes related to these issues are discussed in this section of this 
preamble.
1. Clarifications to Applicability and Certain Definitions
a. NESHAP Subpart AA
    For the applicability section of NESHAP subpart AA, we determined 
that it was unclear whether emissions from clarifiers and 
defluorination systems at wet-process phosphoric acid process lines, 
and oxidation reactors at superphosphoric acid process lines, were 
regulated by the Phosphoric Acid Manufacturing NESHAP. To ensure the 
emission standards we are proposing reflect inclusion of HAP emissions 
from all sources in the defined source category, as initially intended 
in the rule promulgation, we believe it necessary to clarify the 
applicability of the NESHAP. Therefore, we are proposing to amend the 
definitions of wet-process phosphoric acid process line, 
superphosphoric acid process line and purified phosphoric acid process 
line to include relevant emission points, including clarifiers and 
defluorination systems at wet-process phosphoric acid process lines, 
and oxidation reactors at superphosphoric acid production lines. We are 
also proposing to remove text from the applicability section that is 
duplicative of the revised definitions. Defluorination of phosphoric 
acid is performed at several facilities with at least two facilities 
using diatomaceous earth for the process. Oxidation reactors are used 
in the production of SPA at four facilities to remove organics by 
mixing SPA with nitric acid, ammonium nitrate or potassium 
permanganate. These clarifications to the applicability and definitions 
of the standard are more reflective of the source category definition 
that includes any facility engaged in the production of phosphoric 
acid.
    A technical memorandum, ``Applicability Clarifications to the 
Phosphoric Acid Manufacturing Production Source Category,'' in the 
Docket ID No. EPA-HQ-OAR-2012-0522 provides further information on the 
applicability clarifications proposed in this action.
    We also are proposing to revise the term ``gypsum stack'' to 
``gypsum dewatering stack'' in order to help clarify the meaning of 
this fugitive emission source, and to alleviate any potential 
misconception that the ``stack'' is a point source. Other changes 
include the addition of definitions for ``cooling pond,'' ``phosphoric 
acid defluorination process,'' ``process line'' and ``raffinate 
stream''.
b. NSPS Subpart T
    For the applicability section of NSPS subpart T, we determined that 
it was unclear whether emissions from clarifiers and defluorination 
systems at wet-process phosphoric acid plants were regulated by the 
NSPS. To ensure the emission standards we are proposing reflect 
inclusion of total F emissions from all sources in the defined source 
category, as initially intended in the rule promulgation, we believe it 
necessary to clarify the applicability of the NSPS. Therefore, we are 
proposing to amend the definition of wet-process phosphoric acid plant 
to include relevant emission points, including clarifiers and 
defluorination systems. We are also proposing to remove text from the 
applicability section that is duplicative of the revised definitions. 
Defluorination of phosphoric acid is performed at several facilities 
with at least two facilities using diatomaceous earth for the process. 
These clarifications to the applicability and definitions of the 
standard are more reflective of the source category definition that 
includes any facility engaged in the production of phosphoric acid.
    A technical memorandum, ``Applicability Clarifications to the 
Phosphoric Acid Manufacturing Production Source Category,'' in the 
Docket ID No. EPA-HQ-OAR-2012-0522 provides further information on the 
applicability clarifications proposed in this action.
c. NSPS Subpart U
    For the applicability section of NSPS subpart U, we determined that 
it was unclear whether emissions from oxidation reactors at 
superphosphoric acid plants were regulated by the NSPS. To ensure the 
emission standards we are proposing reflect inclusion of total F 
emissions from all sources in the defined source category, as initially 
intended in the rule promulgation, we believe it necessary to clarify 
the applicability of the NSPS. Therefore, we are proposing to amend the 
definition of superphosphoric acid plant to include relevant emission 
points, including oxidation reactors. We are also proposing to remove 
text from the applicability section that is duplicative of the revised 
definitions. Oxidation reactors are used in the production of SPA at 
four facilities to remove organics by mixing SPA with nitric acid, 
ammonium nitrate, or potassium permanganate. These clarifications to 
the applicability and definitions of the standard are more reflective 
of the source category definition that includes any facility engaged in 
the production of phosphoric acid.
    A technical memorandum, ``Applicability Clarifications to the 
Phosphoric Acid Manufacturing Production Source Category,'' in the 
Docket ID No. EPA-HQ-OAR-2012-0522 provides further information on the 
applicability clarifications proposed in this action.
2. What are the startup, shutdown and malfunction requirements?
    The United States Court of Appeals for the District of Columbia 
Circuit vacated portions of two provisions in the EPA's CAA section 112 
regulations governing the emissions of HAP during periods of SSM 
(Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 
S. Ct. 1735 (U.S. 2010)). Specifically, the Court vacated the SSM 
exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1) holding

[[Page 66541]]

that under section 302(k) of the CAA, emissions standards or 
limitations must be continuous in nature and that the SSM exemption 
violates the CAA's requirement that some CAA section 112 standards 
apply continuously.
    We are proposing the elimination of the SSM exemption in this rule. 
Consistent with Sierra Club v. EPA, the EPA is proposing standards in 
this rule that apply at all times. We are also proposing several 
revisions to appendix A of subpart AA (the General Provisions 
Applicability Table) as explained in more detail below. For example, we 
are proposing to eliminate the incorporation of the requirement in the 
General Provisions that the source develop an SSM plan. We also are 
proposing to eliminate and revise certain recordkeeping and reporting 
requirements related to the SSM exemption as further described below.
    The EPA has attempted to ensure that the provisions we are 
proposing to eliminate are inappropriate, unnecessary or redundant in 
the absence of the SSM exemption. We are specifically seeking comment 
on whether we have successfully done so.
    For the reasons explained below, we are proposing work practice 
standards for periods of startup and shutdown in lieu of numerical 
emission limits. CAA section 112(h)(1) states that the Administrator 
may promulgate a design, equipment or operational work practice 
standard in those cases where, in the judgment of the Administrator, it 
is not feasible to prescribe or enforce an emission standard. CAA 
section 112(h)(2)(B) further defines the term ``not feasible'' in this 
context to apply when ``the application of measurement technology to a 
particular class of sources is not practicable due to technological and 
economic limitations.''
    Startup and shutdown periods at phosphoric acid manufacturing 
facilities generally only last between 30 minutes to 6 hours. Because 
of the variability and the relatively short duration compared to the 
time needed to conduct a performance test, which typically requires a 
full working day, the EPA has determined that it is not feasible to 
prescribe a numerical emission standard for these periods. Furthermore, 
according to information provided by industry, it is possible that the 
feed rate (i.e., equivalent P2O5 feed, or rock 
feed) can be zero during startup and shutdown periods. During these 
periods, it is not feasible to consistently enforce the emission 
standards that are expressed in terms of lb of pollutant/ton of feed.
    Although we requested information on emissions and the operation of 
control devices during startup and shutdown periods in the CAA section 
114 survey issued to the Phosphoric Acid Manufacturing source category, 
we did not receive any emissions data collected during a startup and 
shutdown period, and we do not expect that these data exist. However, 
based on the information for control device operation received in the 
survey, we concluded that the control devices could be operated 
normally during periods of startup or shutdown. Also, we believe that 
the emissions generated during startup and shutdown periods are lower 
than during steady-state conditions because the amount of feed 
materials introduced to the process during those periods is lower 
compared to normal operations. Therefore, if the emission control 
devices are operated during startup and shutdown, then HAP emissions 
will be the same or lower than during steady-state operating 
conditions.
    Consequently, we are proposing a work practice standard rather than 
an emissions limit for periods of startup or shutdown. Control devices 
used on the various process lines in this source category are effective 
at achieving desired emission reductions immediately upon start-up. 
Therefore, during startup and shutdown periods, we are proposing that 
sources begin operation of any control device(s) in the production unit 
prior to introducing any feed into the production unit. We are also 
proposing that sources must continue operation of the control device(s) 
through the shutdown period until all feed material has been processed 
through the production unit.
    Periods of startup, normal operations and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead they are, by 
definition sudden, infrequent and not reasonably preventable failures 
of emissions control, process or monitoring equipment. The EPA 
interprets CAA section 112 as not requiring emissions that occur during 
periods of malfunction to be factored into development of CAA section 
112 standards. Under CAA section 112, emissions standards for new 
sources must be no less stringent than the level ``achieved'' by the 
best controlled similar source and for existing sources generally must 
be no less stringent than the average emission limitation ``achieved'' 
by the best-performing 12 percent of sources in the category. There is 
nothing in CAA section 112 that directs the EPA to consider 
malfunctions in determining the level ``achieved'' by the best 
performing sources when setting emission standards. As the United 
States Court of Appeals for the District of Columbia Circuit has 
recognized, the phrase ``average emissions limitation achieved by the 
best performing 12 percent of'' sources ``says nothing about how the 
performance of the best units is to be calculated.'' Nat'l Ass'n of 
Clean Water Agencies v. EPA, 734 F.3d 1115, 1141 (D.C. Cir. 2013). 
While the EPA accounts for variability in setting emissions standards, 
nothing in CAA section 112 requires the agency to consider malfunctions 
as part of that analysis. A malfunction should not be treated in the 
same manner as the type of variation in performance that occurs during 
routine operations of a source. A malfunction is a failure of the 
source to perform in a ``normal or usual manner'' and no statutory 
language compels EPA to consider such events in setting CAA section 112 
standards.
    Further, accounting for malfunctions in setting emission standards 
would be difficult, if not impossible, given the myriad different types 
of malfunctions that can occur across all sources in the category and 
given the difficulties associated with predicting or accounting for the 
frequency, degree and duration of various malfunctions that might 
occur. For these reasons, the performance of units that are 
malfunctioning is not ``reasonably'' foreseeable. See, e.g., Sierra 
Club v. EPA, 167 F.3d 658, 662 (D.C. Cir. 1999) (the EPA typically has 
wide latitude in determining the extent of data gathering necessary to 
solve a problem. We generally defer to an agency's decision to proceed 
on the basis of imperfect scientific information, rather than to 
``invest the resources to conduct the perfect study.''). See also, 
Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) (``In the 
nature of things, no general limit, individual permit, or even any 
upset provision can anticipate all upset situations. After a certain 
point, the transgression of regulatory limits caused by `uncontrollable 
acts of third parties,' such as strikes, sabotage, operator 
intoxication or insanity, and a variety of other eventualities, must be 
a matter for the administrative exercise of case-by-case enforcement 
discretion, not for specification in advance by regulation.''). In 
addition, emissions during a malfunction event can be significantly 
higher than emissions at any other time of source operation. For 
example, if an air pollution control device with 99 percent removal 
goes off-line as a result of a malfunction (as

[[Page 66542]]

might happen if, for example, the bags in a baghouse catch fire) and 
the emission unit is a steady state type unit that would take days to 
shut down, the source would go from 99-percent control to zero control 
until the control device was repaired. The source's emissions during 
the malfunction would be 100 times higher than during normal 
operations, and the emissions over a 4-day malfunction period would 
exceed the annual emissions of the source during normal operations. As 
this example illustrates, accounting for malfunctions could lead to 
standards that are not reflective of (and significantly less stringent 
than) levels that are achieved by a well-performing, non-malfunctioning 
source. It is reasonable to interpret CAA section 112 to avoid such a 
result. The EPA's approach to malfunctions is consistent with CAA 
section 112 and is a reasonable interpretation of the statute.
    In the event that a source fails to comply with the applicable CAA 
section 112 standards as a result of a malfunction event, the EPA would 
determine an appropriate response based on, among other things, the 
good-faith efforts of the source to minimize emissions during 
malfunction periods, including preventative and corrective actions, as 
well as root cause analyses to ascertain and rectify excess emissions. 
The EPA would also consider whether the source's failure to comply with 
the CAA section 112 standard was, in fact, ``sudden, infrequent, not 
reasonably preventable'' and was not instead ``caused in part by poor 
maintenance or careless operation'' 40 CFR 63.2 (definition of 
malfunction).
    If the EPA determines in a particular case that enforcement action 
against a source for violation of an emission standard is warranted, 
the source can raise any and all defenses in that enforcement action 
and the federal district court will determine what, if any, relief is 
appropriate. The same is true for citizen enforcement actions. 
Similarly, the presiding officer in an administrative proceeding can 
consider any defense raised and determine whether administrative 
penalties are appropriate.
    In summary, the EPA interpretation of the CAA and, in particular, 
CAA section 112, is reasonable and encourages practices that will avoid 
malfunctions. Administrative and judicial procedures for addressing 
exceedances of the standards fully recognize that violations may occur 
despite good faith efforts to comply and can accommodate those 
situations.
    In several prior CAA section 112 rules, the EPA had included an 
affirmative defense to civil penalties for violations caused by 
malfunctions in an effort to create a system that incorporates some 
flexibility, recognizing that there is a tension, inherent in many 
types of air regulation, to ensure adequate compliance while 
simultaneously recognizing that despite the most diligent of efforts, 
emission standards may be violated under circumstances entirely beyond 
the control of the source. Although the EPA recognized that its case-
by-case enforcement discretion provides sufficient flexibility in these 
circumstances, it included the affirmative defense to provide a more 
formalized approach and more regulatory clarity. See Weyerhaeuser Co. 
v. Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 1978) (holding that an 
informal case-by-case enforcement discretion approach is adequate); but 
see Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977) 
(requiring a more formalized approach to consideration of ``upsets 
beyond the control of the permit holder.''). Under the EPA's regulatory 
affirmative defense provisions, if a source could demonstrate in a 
judicial or administrative proceeding that it had met the requirements 
of the affirmative defense in the regulation, civil penalties would not 
be assessed. Recently, the United States Court of Appeals for the 
District of Columbia Circuit vacated an affirmative defense in one of 
the EPA's CAA section 112 regulations. NRDC v. EPA, 749 F.3d 1055 (D.C. 
Cir., 2014) (vacating affirmative defense provisions in CAA section 112 
rule establishing emission standards for Portland cement kilns). The 
court found that the EPA lacked authority to establish an affirmative 
defense for private civil suits and held that under the CAA, the 
authority to determine civil penalty amounts in such cases lies 
exclusively with the courts, not the EPA. Specifically, the court 
found: ``As the language of the statute makes clear, the courts 
determine, on a case-by-case basis, whether civil penalties are 
`appropriate.' '' See NRDC, 2014 U.S. App. LEXIS 7281 at *21 (``[U]nder 
this statute, deciding whether penalties are `appropriate' in a given 
private civil suit is a job for the courts, not EPA.'').\28\ In light 
of NRDC, the EPA is not including a regulatory affirmative defense 
provision in the proposed rule. As explained above, if a source is 
unable to comply with emissions standards as a result of a malfunction, 
the EPA may use its case-by-case enforcement discretion to provide 
flexibility, as appropriate. Further, as the D.C. Circuit recognized, 
in an EPA or citizen enforcement action, the court has the discretion 
to consider any defense raised and determine whether penalties are 
appropriate. Cf. NRDC, 2014 U.S. App. LEXIS 7281 at *24 (arguments that 
violation were caused by unavoidable technology failure can be made to 
the courts in future civil cases when the issue arises). The same is 
true for the presiding officer in EPA administrative enforcement 
actions.\29\
---------------------------------------------------------------------------

    \28\ The court's reasoning in NRDC focuses on civil judicial 
actions. The Court noted that ``EPA's ability to determine whether 
penalties should be assessed for Clean Air Act violations extends 
only to administrative penalties, not to civil penalties imposed by 
a court.'' Id.
    \29\ Although the NRDC case does not address the EPA's authority 
to establish an affirmative defense to penalties that is available 
in administrative enforcement actions, the EPA is not including such 
an affirmative defense in the proposed rule. As explained above, 
such an affirmative defense is not necessary. Moreover, assessment 
of penalties for violations caused by malfunctions in administrative 
proceedings and judicial proceedings should be consistent. CF. CAA 
section 113(e) (requiring both the Administrator and the court to 
take specified criteria into account when assessing penalties).
---------------------------------------------------------------------------

a. 40 CFR 63.608(b) General Duty
    We are proposing to revise the entry for 40 CFR 63.6(e)(1)(i) and 
(e)(1)(ii) in the General Provisions table (appendix A) by changing the 
``yes'' in column three to a ``no.'' Section 63.6(e)(1)(i) describes 
the general duty to minimize emissions. Some of the language in that 
section is no longer necessary or appropriate in light of the 
elimination of the SSM exemption. We are proposing instead to add 
general duty regulatory text at 40 CFR 63.608(b) that reflects the 
general duty to minimize emissions while eliminating the reference to 
periods covered by an SSM exemption. The current language in 40 CFR 
63.6(e)(1)(i) characterizes what the general duty entails during 
periods of SSM. With the elimination of the SSM exemption, there is no 
need to differentiate between normal operations, startup and shutdown 
and malfunction events in describing the general duty. Therefore, the 
language the EPA is proposing does not include that language from 40 
CFR 63.6(e)(1). We are also proposing to revise the entry for 40 CFR 
63.6(e)(1)(ii) in the General Provisions table (appendix A) by changing 
the ``yes'' in column three to a ``no.'' Section 63.6(e)(1)(ii) imposes 
requirements that are not necessary with the elimination of the SSM 
exemption or are redundant of the general duty requirement being added 
at 40 CFR 63.608(b).
b. SSM Plan
    We are proposing to revise the entry for 40 CFR 63.6(e)(3) in the 
General

[[Page 66543]]

Provisions table (appendix A) by changing the ``yes'' in column three 
to a ``no.'' Generally, these paragraphs require development of an SSM 
plan and specify SSM recordkeeping and reporting requirements related 
to the SSM plan. As noted, the EPA is proposing to remove the SSM 
exemptions. Therefore, affected units will be subject to an emission 
standard during such events. The applicability of a standard during 
such events will ensure that sources have ample incentive to plan for 
and achieve compliance and thus the SSM plan requirements are no longer 
necessary.
c. Compliance With Standards
    We are proposing to revise the entry for 40 CFR 63.6(f) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' The current language of 40 CFR 63.6(f)(1) exempts 
sources from non-opacity standards during periods of SSM. As discussed 
above, the court in Sierra Club vacated the exemptions contained in 
this provision and held that the CAA requires that some CAA section 112 
standard apply continuously. Consistent with Sierra Club, the EPA is 
proposing to revise standards in this rule to apply at all times.
d. 40 CFR 63.606 Performance Testing
    We are proposing to revise the entry for 40 CFR 63.7(e)(1) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' Section 63.7(e)(1) describes performance testing 
requirements. The EPA is instead proposing to add a performance testing 
requirement at 40 CFR 63.606(d). The performance testing requirements 
we are proposing to add differ from the General Provisions performance 
testing provisions in several respects. The proposed regulatory text 
does not allow testing during startup, shutdown or malfunction. The 
proposed regulatory does not include the language in 40 CFR 63.7(e)(1) 
that restated the SSM exemption and language that precluded startup and 
shutdown periods from being considered ``representative'' for purposes 
of performance testing. Furthermore, as in 40 CFR 63.7(e)(1), 
performance tests conducted under this subpart should not be conducted 
during malfunctions because conditions during malfunctions are often 
not representative of operating conditions.
    We are proposing that sources conduct performance tests during 
``maximum representative operating conditions for the process''. 
Specifically, we are proposing that sources must operate your process 
during the performance test in such a way that results in the flue gas 
characteristics that are the most difficult for reducing emissions of 
the regulated pollutant(s) by the control device used. In an effort to 
provide more flexibility to owners and operators regarding the 
identification of the proper testing conditions, the most difficult 
condition for the control device may include, but is not limited to, 
the highest HAP mass loading rate to the control device, or the highest 
HAP mass loading rate of constituents that approach the limits of 
solubility for scrubbing media. The EPA understands that there may be 
cases where efficiencies are dependent on other characteristics of 
emission streams, including the characteristics of components and the 
operating principles of the devices. For example, the solubility of 
emission stream components in scrubbing media, or emission stream 
component affinity in carbon adsorption systems can also define the 
most difficult condition for a particular control device. The EPA is 
also proposing to add language that requires the owner or operator to 
record the process information that is necessary to document operating 
conditions during the test and include in such record an explanation to 
support that such conditions represent maximum representative operating 
conditions. Section 63.7(e) requires that the owner or operator make 
available to the Administrator upon request such records ``as may be 
necessary to determine the condition of the performance test,'' but did 
not specifically require the owner or operator to record the 
information. The regulatory text the EPA is proposing to add builds on 
that requirement and makes explicit the requirement to record the 
information.
e. Monitoring
    We are proposing to revise the entry for 40 CFR 63.8(c)(1)(i) and 
(iii) in the General Provisions table by changing the ``yes'' in column 
three to a ``no.'' The cross-references to the general duty and SSM 
plan requirements in those subparagraphs are not necessary in light of 
other requirements of 40 CFR 63.8 that require good air pollution 
control practices (40 CFR 63.8(c)(1)) and that set out the requirements 
of a quality control program for monitoring equipment (40 CFR 63.8(d)).
    We are proposing to revise the entry for 40 CFR 63.8(d)(3) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' The final sentence in 40 CFR 63.8(d)(3) refers to 
the General Provisions' SSM plan requirement, which is no longer 
applicable. The EPA is proposing to add to the rule at 40 CFR 
63.608(c)(4) text that is identical to 40 CFR 63.8(d)(3), except that 
the final sentence is replaced with the following sentence: ``You must 
include the program of corrective action required under Sec.  
63.8(d)(2) in the plan.''
f. 40 CFR 63.607 Recordkeeping
    We are proposing to revise the entry for 40 CFR 63.10(b)(2)(i) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' Section 63.10(b)(2)(i) describes the 
recordkeeping requirements during startup and shutdown. These recording 
provisions are no longer necessary because the EPA is proposing that 
recordkeeping and reporting applicable to normal operations will apply 
to startup and shutdown. In the absence of special provisions 
applicable to startup and shutdown, such as a startup and shutdown 
plan, there is no reason to retain additional recordkeeping for startup 
and shutdown periods.
    We are proposing to revise the entry for 40 CFR 63.10(b)(2)(ii) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' Section 63.10(b)(2)(ii) describes the 
recordkeeping requirements during a malfunction. The EPA is proposing 
to add such requirements to 40 CFR 63.607(b). The regulatory text we 
are proposing to add differs from the General Provisions it is 
replacing in that the General Provisions requires the creation and 
retention of a record of the occurrence and duration of each 
malfunction of process, air pollution control and monitoring equipment. 
The EPA is proposing that this requirement apply to any failure to meet 
an applicable standard and that the source record the date, time and 
duration of the failure rather than the ``occurrence.'' The EPA is also 
proposing to add to 40 CFR 63.607(b) a requirement that sources keep 
records that include a list of the affected source or equipment and 
actions taken to minimize emissions, an estimate of the volume of each 
regulated pollutant emitted over the applicable standard and a 
description of the method used to estimate the emissions. Examples of 
such methods would include product-loss calculations, mass balance 
calculations, measurements when available or engineering judgment based 
on known process parameters. The EPA is proposing to require that 
sources keep records of this information to ensure that there is 
adequate information to allow the EPA to determine the severity of any 
failure to meet a standard, and to provide data

[[Page 66544]]

that may document how the source met the general duty to minimize 
emissions when the source has failed to meet an applicable standard.
    We are proposing to revise the entry for 40 CFR 63.10(b)(2)(iv) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' When applicable, the provision requires 
sources to record actions taken during SSM events when actions were 
inconsistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required. The 
requirement previously applicable under 40 CFR 63.10(b)(2)(iv)(B) to 
record actions to minimize emissions and record corrective actions is 
now applicable by reference to 40 CFR 63.607.
    We are proposing to revise the entry for 40 CFR 63.10(b)(2)(v) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' When applicable, the provision requires 
sources to record actions taken during SSM events to show that actions 
taken were consistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required.
    We are proposing to revise the entry for 40 CFR 63.10(c)(15) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' The EPA is proposing that 40 CFR 63.10(c)(15) no 
longer apply. When applicable, the provision allows an owner or 
operator to use the affected source's SSM plan or records kept to 
satisfy the recordkeeping requirements of the SSM plan, specified in 40 
CFR 63.6(e), to also satisfy the requirements of 40 CFR 63.10(c)(10) 
through (12). The EPA is proposing to eliminate this requirement 
because SSM plans would no longer be required, and, therefore, 40 CFR 
63.10(c)(15) no longer serves any useful purpose for affected units.
g. 40 CFR 63.607 Reporting
    We are proposing to revise the entry for 40 CFR 63.10(d)(5) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' Section 63.10(d)(5) describes the reporting 
requirements for startups, shutdowns and malfunctions. To replace the 
General Provisions reporting requirement, the EPA is proposing to add 
reporting requirements to 40 CFR 63.607. The replacement language 
differs from the General Provisions requirement in that it eliminates 
periodic SSM reports as a stand-alone report. We are proposing language 
that requires sources that fail to meet an applicable standard at any 
time to report the information concerning such events in the excess 
emission report already required under this rule. We are proposing that 
the report must contain the number, date, time, duration and the cause 
of such events (including unknown cause, if applicable), a list of the 
affected source or equipment, an estimate of the volume of each 
regulated pollutant emitted over any emission limit, and a description 
of the method used to estimate the emissions (e.g., product-loss 
calculations, mass balance calculations, direct measurements or 
engineering judgment based on known process parameters). The EPA is 
proposing this requirement to ensure that adequate information is 
available to determine compliance, to allow the EPA to determine the 
severity of the failure to meet an applicable standard, and to provide 
data that may document how the source met the general duty to minimize 
emissions during a failure to meet an applicable standard.
    The proposed rule eliminates the cross reference to 40 CFR 
63.10(d)(5)(i) that contains the description of the previously-required 
SSM report format and submittal schedule from this section. These 
specifications are no longer necessary because the events will be 
reported in otherwise required reports with similar format and 
submittal requirements. We are proposing that owners or operators no 
longer be required to determine whether actions taken to correct a 
malfunction are consistent with an SSM plan because the plans would no 
longer be required.
    We are proposing to revise the entry for 40 CFR 63.10(d)(5)(ii) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' Section 63.10(d)(5)(ii) describes an 
immediate report for SSM when a source failed to meet an applicable 
standard but did not follow the SSM plan. We will no longer require 
owners and operators to report when actions taken during a startup, 
shutdown or malfunction were not consistent with an SSM plan because 
the plans would no longer be required.
3. Testing, Monitoring, Recordkeeping and Reporting
a. NESHAP Subpart AA
    For wet scrubbers, we are proposing alternatives to the existing 
requirement to monitor pressure differential across the scrubber. We 
received input from industry that the pressure differential is not a 
reliable method of determining the performance of a scrubber because 
fouling occurs over time, increasing the pressure differential. The 
pressure differential immediately after cleaning will be much lower 
than that after the scrubber has operated for some time. Therefore, to 
provide flexibility, we have included several monitoring options, 
including pressure and temperature measurements, as alternatives to 
monitoring of scrubber differential pressure. We are also adding 
flexibility in the existing requirement to measure the flow rate of the 
scrubbing liquid to each scrubber (i.e., the inlet liquid flow rate to 
a scrubber). We are proposing that the inlet liquid-to-gas ratio may 
now be monitored in lieu of the inlet liquid flow rate, which provides 
the ability to lower liquid flow rate with changes in gas flow rate to 
the scrubber.
    We are removing the requirement that facilities may not implement 
new operating parameter ranges until the Administrator has approved 
them, or 30 days have passed since submission of the performance test 
results. For the proposed requirements, facilities must immediately 
comply with new operating ranges when they are developed and submitted. 
New operating ranges must also be established using the most recent 
performance test conducted by a facility, which allows for changes in 
control device operation to be appropriately reflected.
    Because control devices may be necessary to meet the proposed Hg 
limits for phosphate rock calciners, we are proposing monitoring and 
testing requirements in subpart AA for the two types of control systems 
evaluated as alternatives for control of Hg: Adsorbers (typically fixed 
bed carbon), and sorbent injection (i.e., ACI) followed by a WESP or 
followed by fabric filtration. We are also proposing the addition of 
methods to monitor emissions of Hg using continuous emissions 
monitoring systems (CEMS).
    As described in section IV.E.2.d of this preamble, for all 
processes, we have also modified the language for the conditions under 
which testing must be conducted to require that testing be conducted at 
maximum representative operating conditions for the process.
    In keeping with the general provisions for continuous monitoring 
systems (CMS) (including CEMS and continuous parameter monitoring 
system (CPMS)), we are proposing the addition of a site-specific 
monitoring plan and calibration requirements for CMS. Provisions are 
also included for electronic reporting of stack test data.
    We have also modified the format of the NESHAP to reference tables 
for emissions limits and monitoring requirements.

[[Page 66545]]

b. NSPS Subpart T
    The EPA evaluated the monitoring and recordkeeping requirements 
currently required in NSPS subpart T to determine if they are adequate 
for determining compliance. Currently under NSPS subpart T, an owner or 
operator of a wet-process phosphoric acid plant is required to install, 
calibrate, maintain and operate a monitoring device which continuously 
measures and permanently records the total pressure drop across the 
process scrubbing system. However, the current rule does not require an 
owner or operator to establish, and demonstrate continuous compliance 
with, an allowable range for the pressure drop through the process 
scrubbing system. Therefore, we are proposing new monitoring and 
recordkeeping requirements for any wet-process phosphoric acid plant 
that commences construction, modification or reconstruction after [date 
of publication of the final rule in the Federal Register] to ensure 
continuous compliance with the standard.
    We are proposing that for any wet-process phosphoric acid plant 
that commences construction, modification or reconstruction after [date 
of publication of the final rule in the Federal Register] the owner or 
operator establish an allowable range for the pressure drop through the 
process scrubbing system. The allowable range would be established 
during the performance test required in 40 CFR 60.8. We also propose 
that the allowable range is 20 percent of the arithmetic 
average of the three test runs conducted during the performance test. 
In addition, the owner or operator would be required to maintain the 
daily average pressure drop through the process scrubbing system within 
the allowable range; and valid data points must be available for 75 
percent of the operating hours in an operating day to compute the daily 
average. We also propose that the owner or operator keep records of the 
daily average pressure drop through the process scrubbing system, and 
keep records of deviations. We are proposing these monitoring and 
recordkeeping requirements in order to: Ensure that the process 
scrubbing system is properly maintained over time; ensure continuous 
compliance with standards; and improve data accessibility.
    Finally, for consistency with terminology used in the associated 
NESHAP subpart AA, we have changed the term ``process scrubbing 
system'' to ``absorber.''
    We do not expect any costs associated with these proposed 
monitoring and recordkeeping requirements. These proposed requirements 
will only apply to new sources, and we are not aware of any planned new 
sources. Also, we believe that most, if not all, new sources will be 
exempt from NSPS subpart T compliance due to the likelihood of the new 
source being subject to NESHAP subpart AA.
c. NSPS Subpart U
    The EPA evaluated the monitoring and recordkeeping requirements 
currently required in NSPS subpart U to determine if they are adequate 
for determining compliance. Currently under NSPS subpart U, an owner or 
operator of a superphosphoric acid plant is required to install, 
calibrate, maintain and operate a monitoring device which continuously 
measures and permanently records the total pressure drop across the 
process scrubbing system. However, the current rule does not require an 
owner or operator to establish, and demonstrate continuous compliance 
with, an allowable range for the pressure drop through the process 
scrubbing system. Therefore, we are proposing new monitoring and 
recordkeeping requirements for any superphosphoric acid plant that 
commences construction, modification or reconstruction after [date of 
publication of the final rule in the Federal Register] to ensure 
continuous compliance with the standard.
    We are proposing that for any superphosphoric acid plant that 
commences construction, modification or reconstruction after [date of 
publication of the final rule in the Federal Register] the owner or 
operator establish an allowable range for the pressure drop through the 
process scrubbing system. The allowable range would be established 
during the performance test required in 40 CFR 60.8. We also propose 
that the allowable range is 20 percent of the arithmetic 
average of the three test runs conducted during the performance test. 
In addition, the owner or operator would be required to maintain the 
daily average pressure drop through the process scrubbing system within 
the allowable range; and valid data points must be available for 75 
percent of the operating hours in an operating day to compute the daily 
average. We also propose that the owner or operator keep records of the 
daily average pressure drop through the process scrubbing system, and 
keep records of deviations. We are proposing these monitoring and 
recordkeeping requirements in order to: ensure that the process 
scrubbing system is properly maintained over time; ensure continuous 
compliance with standards; and improve data accessibility.
    Finally, for consistency with terminology used in the associated 
NESHAP subpart AA, we have changed the term ``process scrubbing 
system'' to ``absorber.''
    We do not expect any costs associated with these proposed 
monitoring and recordkeeping requirements. These proposed requirements 
will only apply to new sources, and we are not aware of any planned new 
sources. Also, we believe that most, if not all, new sources will be 
exempt from NSPS subpart U compliance due to the likelihood of the new 
source being subject to NESHAP subpart AA.
4. Translation of Total F to HF Emission Limits
    The EPA is proposing to translate the current total F limit (lb 
total F/ton P2O5 feed) into an HF limit (lb HF/
ton P2O5 feed). The current standard uses total F 
as a surrogate for HF, and as such, the standard allows for a scenario 
where 100 percent of all total F emissions could be HF. Therefore, we 
are proposing HF limits as the same numeric values as the current total 
F limits. We recognize that on a mass basis, HF emissions will be 
slightly greater than total F emissions; however, this relatively small 
difference of approximately 5 percent is negligible in measurement of 
the pollutant. Additionally, based on test data provided by industry, 
the EPA believes that moving to a form of the standard that requires HF 
to be measured, but retains the same numeric values as the current 
total F standards will be achievable by all facilities. We are 
proposing that sources would annually demonstrate compliance with the 
HF limit using EPA Method 320.
    The resulting new and existing HF emission source limits are 
summarized in Table 6 of this preamble.

[[Page 66546]]



         Table 6--Summary of Proposed HF Emission Limits for New and Existing Phosphoric Acid Facilities
----------------------------------------------------------------------------------------------------------------
                                                   Current total F limits *            Proposed HF limits *
             Regulated process              --------------------------------------------------------------------
                                                Existing             New             Existing           New
----------------------------------------------------------------------------------------------------------------
WPPA Line..................................           0.020            0.0135              0.020       0.0135
SPA Line...................................           0.010            0.00870             0.010       0.00870
----------------------------------------------------------------------------------------------------------------
* All limits expressed as lbs/ton P2O5 feed.

    With this proposal, we are seeking comment on finalizing the HF 
limit for regulating HF emissions using the target HAP (HF), instead of 
the long-standing surrogate for HF, total F. We invite comment on 
determining and setting a standard for HF in lieu of the existing total 
F standard. We solicit comment on our proposed decision.
    We also seek comment on the use of EPA Method 320 for the 
compliance demonstration test method. Additionally, we solicit comment 
on the use of Fourier transform infrared spectroscopy (FTIR) HF CEMS as 
an optional continuous monitoring compliance approach within the rule. 
We also invite comment on the use of an HF emission standard where a 
source using an HF CEMS would comply with a 30-day rolling average 
emission limit, and annual relative accuracy test audit (RATA) 
certifications of CEMS. A technical memorandum, ``Hydrogen Fluoride 
Continuous Emission Monitoring and Compliance Determination with EPA 
Method 320,'' in the Docket ID No. EPA-HQ-OAR-2012-0522 outlines 
technical detail on the use of HF CEMS and is provided as guidance for 
comments regarding details of a continuous HF monitoring option.
    To allow facilities flexibility in demonstrating compliance, we are 
also considering an option to maintain the existing total F limits as 
an alternative addition to the proposed HF limits. Facilities would be 
required to comply with all of the provisions in this proposed 
rulemaking, including the emission standards, and the operating, 
monitoring, notification, recordkeeping and reporting requirements; 
however, facilities would have the option to comply with either the 
proposed HF limits using EPA Method 320, or the current total F limits 
using EPA Method 13B. This option would be implemented by revising 40 
CFR 63.602(a) and Tables 1, 1a, 2 and 2a to subpart AA to include both 
HF and total F limits; all other provisions would remain as proposed in 
subpart AA. We solicit comment on allowing facilities to demonstrate 
compliance with the current total F limits as an alternative to the 
proposed HF limits.

F. What are the notification, recordkeeping and reporting requirements 
for the Phosphoric Acid Manufacturing source category?

    In this proposal, the EPA is describing a process to increase the 
ease and efficiency of submitting performance test data while improving 
data accessibility. Specifically, the EPA is proposing that owners and 
operators of phosphoric acid manufacturing facilities submit electronic 
copies of required performance test and performance evaluation reports 
by direct computer-to-computer electronic transfer using EPA-provided 
software. The direct computer-to-computer electronic transfer is 
accomplished through the EPA's Central Data Exchange (CDX) using the 
Compliance and Emissions Data Reporting Interface (CEDRI). The CDX is 
the EPA's portal for submittal of electronic data. The EPA-provided 
software is called the Electronic Reporting Tool (ERT), which is used 
to generate electronic reports of performance tests and evaluations. 
The ERT generates an electronic report package that facilities will 
submit using CEDRI. The submitted report package will be stored in the 
CDX archive (the official copy of record) and the EPA's public database 
called WebFIRE. All stakeholders will have access to all reports and 
data in WebFIRE and accessing these reports and data will be very 
straightforward and easy (see the WebFIRE Report Search and Retrieval 
link at https://cfpub.epa.gov/webfire/index.cfm?action=fire.searchERTSubmission). A description and 
instructions for use of the ERT can be found at https://www.epa.gov/ttn/chief/ert/ and CEDRI can be accessed through the CDX Web site 
(www.epa.gov/cdx). A description of the WebFIRE database is available 
at: https://cfpub.epa.gov/oarweb/index.cfm?action=fire.main.
    The proposal to submit performance test data electronically to the 
EPA applies only to those performance tests and/or performance 
evaluations conducted using test methods that are supported by the ERT. 
The ERT supports most of the commonly used EPA reference test methods. 
A listing of the pollutants and test methods supported by the ERT is 
available at: https://www.epa.gov/ttn/chief/ert/.
    We believe that industry would benefit from this proposed approach 
to electronic data submittal. Specifically, by using this approach, 
industry will save time in the performance test submittal process. 
Additionally, the standardized format that the ERT uses allows sources 
to create a more complete test report, resulting in less time spent on 
backfilling data if a source failed to submit all required data 
elements. Also through this proposal, industry may only need to submit 
a report once to meet the requirements of the applicable subpart 
because stakeholders can readily access these reports from the WebFIRE 
database. This also benefits industry by reducing recordkeeping costs 
as the performance test reports that are submitted to the EPA using 
CEDRI are no longer required to be retained in hard copy, thereby, 
reducing staff time needed to coordinate these records.
    Because the EPA will already have performance test data in hand, 
another benefit to industry of electronic reporting is that fewer or 
less substantial data collection requests in conjunction with 
prospective required residual risk assessments or technology reviews 
will be needed. This would result in a decrease in staff time needed to 
respond to data collection requests.
    State, local and tribal air pollution control agencies may also 
benefit from having electronic versions of the reports they are now 
receiving. For example, state, local and tribal air pollution control 
agencies may be able to conduct a more streamlined and accurate review 
of electronic data submitted to them. For example, the ERT would allow 
for an electronic review process, rather than a manual data assessment, 
therefore, making their review and evaluation of the source-provided 
data and calculations easier and more efficient. In addition, the 
public stands to benefit from electronic reporting of emissions data 
because the electronic data will be easier for the public to access. 
The methods and procedures for collecting, accessing and reviewing air 
emissions

[[Page 66547]]

data will be more transparent for all stakeholders.
    One major advantage of the proposed submittal of performance test 
data through the ERT is a standardized method to compile and store much 
of the documentation required to be reported by this rule. The ERT 
clearly states the information required by the test method and ERT has 
the ability to house additional data elements that might be required by 
a delegated authority.
    In addition, the EPA must have performance test data to conduct 
effective reviews of CAA sections 112 standards as well as for many 
other purposes including compliance determinations, emission factor 
development and annual emission rate determinations. In conducting 
these required reviews, the EPA has found it ineffective and time 
consuming, not only for us, but also for regulatory agencies and source 
owners and operators, to locate, collect and submit performance test 
data. Also, in recent years, stack testing firms have typically 
collected performance test data in electronic format, making it 
possible to move to an electronic data submittal system that would 
increase the ease and efficiency of data submittal and improve data 
accessibility.
    A common complaint heard from industry and regulators is that 
emission factors are outdated or not representative of a particular 
source category. With timely receipt and incorporation of data from 
most performance tests, the EPA would be able to ensure that emission 
factors, when updated, represent the most current range of operational 
practices. Finally, another benefit of the proposed electronic data 
submittal to WebFIRE is that these data would greatly improve the 
overall quality of existing and new emissions factors by supplementing 
the pool of emissions test data that the EPA evaluates to develop 
emissions factors.
    In summary, in addition to supporting regulation development, 
control strategy development and other air pollution control 
activities, having an electronic database populated with performance 
test data would save industry, state, local, tribal agencies and the 
EPA significant time, money and effort while also improving the quality 
of emission factors and inventories and air quality regulations.

G. What compliance dates are we proposing for the Phosphoric Acid 
Manufacturing source category?

    We are proposing that facilities must comply with the proposed Hg 
limits for existing rock calciners no later than 3 years after the 
effective date of this rule. We are proposing a 3-year compliance lead 
time so that facilities with existing rock calciners have adequate time 
to design and install additional controls and demonstrate compliance, 
including the time necessary to: construct control devices; seek bids, 
select a vendor and install and test the new equipment; and purchase 
and install compliance monitoring equipment and implement quality 
assurance measures. We believe that three years are needed for 
facilities with existing rock calciners to complete the steps described 
above and achieve compliance with the proposed standards. For new rock 
calciners that commence construction or reconstruction after December 
27, 1996, and on or before the effective date of this rule, we are 
proposing that facilities must comply with the proposed Hg limits no 
later than 1 year after the effective date of this rule. New rock 
calciners that commence construction or reconstruction after the 
effective date of this rule would comply with the proposed Hg limits 
immediately upon startup. We are also proposing the compliance date for 
HF work practice standards for all (existing and new) rock calciners is 
the effective date of this rule. Based on the data that the EPA has 
received, all rock calciners are meeting the HF work practice standard; 
therefore, no additional time would be required to achieve compliance 
with this HF work practice standard. We specifically seek comment on 
the compliance dates proposed for regulating Hg and HF from new and 
existing phosphate rock calciners.
    In addition, for existing gypsum dewatering stack or cooling ponds, 
we are proposing that facilities must prepare and comply with a gypsum 
dewatering stack and cooling pond management plan to control fugitive 
HF emissions no later than 1 year after the effective date of this 
rule. For new gypsum dewatering stack or cooling ponds, we are 
proposing that facilities must prepare and comply with a gypsum 
dewatering stack and cooling pond management plan to control fugitive 
HF emissions beginning on the effective date of this rule.
    We are also proposing that for existing and new wet-process 
phosphoric acid process lines and superphosphoric acid process lines 
that commence construction or reconstruction on or before the effective 
date of this rule, the facility must comply with the proposed HF limits 
no later than 1 year after the effective date of this rule. Facilities 
will continue to conduct the annual performance test, but will be 
required to use a different test method. Therefore, we are proposing a 
one-year compliance lead time so that facilities have adequate time to 
coordinate performance testing with the new test method. We do not 
anticipate that any facilities will need to install a new control 
device to meet the proposed HF limits. For new wet-process phosphoric 
acid process lines and superphosphoric acid process lines that commence 
construction or reconstruction after the effective date of this rule, 
the facility must comply with the proposed HF limits beginning on the 
effective date of this rule. Prior to these compliance dates (for HF 
limits), we are proposing that facilities continue to comply with the 
current total F standards.
    We are also proposing that the compliance date for the amended SSM 
requirements is the effective date of this rule.

V. Analytical Results and Proposed Decisions for the Phosphate 
Fertilizer Production Source Category

A. What are the results of the risk assessment and analyses for the 
Phosphate Fertilizer Production source category?

    The preamble sections below summarize the results of the risk 
assessments for the Phosphate Fertilizer Production source category. 
The complete risk assessment, Draft Residual Risk Assessment for 
Phosphate Fertilizer Production and Phosphoric Acid Manufacturing, is 
available in the docket for this action.
1. Inhalation Risk Assessment Results
    The basic chronic inhalation risk estimates presented here are the 
maximum individual lifetime cancer risk, the maximum chronic HI and the 
cancer incidence. We also present results from our acute inhalation 
impact screening in the form of maximum HQs, as well as the results of 
our preliminary screening for potential non-inhalation risks from PB-
HAP. Also presented are the HAP ``drivers,'' which are the HAP that 
collectively contribute 90 percent of the maximum cancer risk or 
maximum HI at the highest exposure location.
    The inhalation risk results for this source category indicate that 
maximum lifetime individual cancer risks are less than 1-in-1 million. 
The total estimated cancer incidence from this source category is 0.001 
excess cancer cases per year, or one excess case in every 1,000 years. 
The maximum chronic non-cancer TOSHI value for the source category 
could be up to 0.1 associated with emissions of manganese, indicating 
no significant potential for chronic non-cancer impacts.

[[Page 66548]]

    We analyzed the potential differences between actual emissions 
levels and calculated the maximum emissions allowable under the MACT 
standards for every emission process group for this source category. 
Based upon the above analysis, we multiplied the modeled actual risks 
for the MIR facility with site-specific process multipliers to estimate 
allowable risks under the MACT. We deemed this approach sufficient due 
to the low actual modeled risks for the source category. The maximum 
lifetime individual cancer risks based upon allowable emissions are 
still less than 1-in-1 million. The maximum chronic non-cancer TOSHI 
value is also estimated at an HI of 0.1.
2. Acute Risk Results
    Worst-case acute HQs were calculated for every HAP that has an 
acute benchmark. There were no phosphate fertilizer production 
facilities identified with HQ values greater than 1.
3. Multipathway Risk Screening Results
    For the Phosphate Fertilizer Production source category, the EPA 
conducted a Tier I screening-level evaluation of the potential human 
health risks associated with emissions of PB-HAP. The PB-HAP emitted by 
facilities in this category include Hg compounds (11 facilities), Pb 
compounds (11 facilities), and cadmium compounds (11 facilities). We 
compared reported emissions of PB-HAP to the Tier I screening emission 
thresholds established by the EPA for the purposes of the RTR risk 
assessments. One facility emitted Hg\2+\ above the Tier I screening 
threshold level, exceeding the screening threshold by a factor of 20. 
Consequently, we found it necessary to conduct a Tier II screening 
assessment.
    For the Tier II screening assessment, we refined our Hg\2+\ 
analysis with additional site-specific information. The additional 
site-specific information included the land use around the facilities, 
the location of fishable lakes and local meteorological data such as 
wind direction. The result of this analysis was the development of a 
site-specific emission screening threshold for Hg\2+\. This assessment 
uses the assumption that the biological productivity limitation of each 
lake is 1 gram of fish per acre of water, meaning that in order to 
fulfill the adult ingestion rate, the fisher will need to fish from 373 
total acres of lakes. The result of this analysis was the development 
of a site-specific emission screening threshold for Hg\2+\. We compared 
this Tier II screening threshold for Hg\2+\ to the facility's Hg\2+\ 
emissions. The facility's emissions exceeded the Tier II screening 
threshold, by a factor of 3.
    To refine our Hg Tier II Screen for this facility, we first 
examined the set of lakes from which the angler ingested fish. Any 
lakes that appeared to not be fishable or publicly accessible were 
removed from the assessment, and the screening assessment was repeated. 
After we made the determination the three critical lakes were fishable, 
we analyzed the hourly meteorology data from which the Tier II 
meteorology statistics were derived. Using buoyancy and momentum 
equations from literature, and assumptions about facility fenceline 
boundaries, we estimated by hour the height achieved by the emission 
plume before it moved laterally beyond the assumed fenceline. If the 
plume height was above the mixing height, we assumed there was no 
chemical exposure for that hour. The cumulative loss of chemical being 
released above the mixing height reduces the exposure and decreases the 
Tier II screening quotient. The refined Tier II analysis for mercury 
emissions indicated a 23-percent loss of emissions above mixing layer 
due to plume rise, this reduction still resulted in an angler screening 
non-cancer value equal to 2.
    For this facility, after we performed the lake and plume rise 
analyses, we reran the relevant Tier II screening scenarios for the 
travelling subsistence angler in TRIM.FaTE with the same hourly 
meteorology data and hourly plume-rise adjustments from which the Tier 
II meteorology statistics were derived. The utilization of the time-
series meteorology reduced the screening value further to a value of 
0.6. For this source category our analysis indicated no potential for 
multipathway impacts of concern from this facility.
    For the other PB-HAP emitted by facilities in the source category, 
no facilities emit cadmium above the Tier I screening threshold level. 
Lead is a PB-HAP, but the NAAQS value (which was used for the chronic 
noncancer risk assessment) takes into account multipathway exposures, 
so a separate multipathway screening value was not developed. Since we 
did not estimate any exceedances of the NAAQS in our chronic noncancer 
risk assessment, we do not expect any significant multipathway exposure 
and risk due to Pb emissions from these facilities. For more 
information on the multipathway screening assessment conducted for this 
source category, see the memorandum, ``Draft Residual Risk Assessment 
for Phosphate Fertilizer Production and Phosphoric Acid Manufacturing'' 
provided in the docket for this rulemaking.
4. Environmental Risk Screening Results
    As described in section III.A.5 of this preamble, we conducted an 
environmental risk screening assessment for the Phosphate Fertilizer 
Production source category. In the Tier I screening analysis for PB-HAP 
(other than Pb, which was evaluated differently as noted in section 
III.A.5 of this preamble) none of the individual modeled concentrations 
for any facility in the source category exceeds any of the ecological 
benchmarks (either the LOAEL or NOAEL). Therefore, we did not conduct a 
Tier II assessment. For Pb, we did not estimate any exceedances of the 
secondary Pb NAAQS.
    For acid gases, the average modeled concentration around each 
facility (i.e., the average concentration of all off-site data points 
in the modeling domain) did not exceed any ecological benchmark (either 
the LOAEL or NOAEL). HCl emissions were not identified from the 
category. For HF, each individual concentration (i.e., each off-site 
data point in the modeling domain) was below the ecological benchmarks 
for all facilities. We did not identify an adverse environmental effect 
as defined in CAA section 112(a)(7) from HAP emissions from this source 
category.
5. Facility-Wide Risk Results
    The facility-wide MIR and TOSHI are based on emissions, as 
identified in the NEI, from all emissions sources at the identified 
facilities. The results of the facility-wide analysis indicate that all 
11 facilities with phosphate fertilizer production have a facility-wide 
cancer MIR less than or equal to 1-in-1 million. The maximum facility-
wide TOSHI for the source category is 0.2. The risk results are 
summarized in Table 7 of this preamble.

[[Page 66549]]



                                        Table 7--Human Health Risk Assessment for Phosphate Fertilizer Production
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Cancer MIR  (in 1                                             Max chronic  non-cancer
                                              million)             Cancer     Population   Population             HI
  Category & number  of facilities   --------------------------  incidence    with risks   with risks --------------------------  Worst-case  max acute
               modeled                  Based on     Based on    (cases per   of 1-in-1    of 10-in-1    Based on     Based on        non-cancer HQ
                                         actual     allowable      year)     million  or   million or     actual     allowable
                                       emissions    emissions                    more         more      emissions    emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Phosphate Fertilizer................          0.5          0.5        0.001            0            0         0.02         0.02  HQREL = 0.4 (elemental
(11 facilities).....................                                                                                              Hg).
                                      ...........  ...........  ...........  ...........  ...........  ...........  ...........  HQAEGL-1 = 0.09
                                                                                                                                  (hydrofluoric acid).
                                      ...........  ...........  ...........  ...........  ...........  ...........  ...........  --
--------------------------------------------------------------------------------------------------------------------------------------------------------
Facility-wide (11 facilities).......          0.5          0.5        0.001            0            0          0.2          0.3  --
--------------------------------------------------------------------------------------------------------------------------------------------------------

6. What demographic groups might benefit from this regulation?

    To determine whether or not to conduct a demographics analysis, we 
look at a combination of factors including the MIR, non-cancer TOSHI, 
population around the facilities in the source category, and other 
relevant factors. For the Phosphate Fertilizer Production source 
category, the MIR is less than 1-in-1 million, and the HI is less than 
1 and, therefore, we did not conduct an assessment of risks to 
individual demographic groups for this rulemaking. However, we did 
conduct a proximity analysis, which identifies any overrepresentation 
of minority, low income or indigenous populations near facilities in 
the source category. The results of this analysis are presented in 
section IX.J of this preamble.

B. What are our proposed decisions regarding risk acceptability, ample 
margin of safety and adverse environmental effects for the Phosphate 
Fertilizer Production source category?

1. Risk Acceptability
    The results of both the source category and facility-wide risk 
assessments indicate that all phosphate fertilizer production 
facilities have a cancer MIR less than 1-in-1 million. The maximum 
source category and facility-wide TOSHI are both less than 1, and the 
maximum worst-case acute non-cancer HQ is less than 1. We propose that 
the risks posed by emissions from this source category are acceptable.
2. Ample Margin of Safety Analysis and Proposed Controls
    Under the ample margin of safety analysis, we evaluate the cost and 
feasibility of available control technologies and other measures 
(including the controls, measures and costs evaluated under the 
technology review) that could be applied in this source category to 
further reduce the risks due to emissions of HAP identified in our risk 
assessment, as well as the health impacts of such potential additional 
measures. As noted in our discussion of the technology review in 
section V.C of this preamble, no measures (beyond those already in 
place) were identified for reducing HAP emissions from the Phosphate 
Fertilizer source category. In addition, because our analyses show that 
the maximum baseline chronic cancer risk is below 1-in-1 million, the 
maximum chronic non-cancer HI is less than 1, and the worst-case acute 
HQ is less than the CA-REL, minimal reductions in risk could be 
achieved even if we identified measures that could reduce HAP emissions 
further. Based on the discussion above, we propose that the current 
standards provide an ample margin of safety to protect public health.
    Though we did not identify any new technologies to reduce risk from 
this source category, we are specifically requesting comment on whether 
there are additional control measures that may be able to reduce risks 
from the source category. We request any information on potential 
emission reductions of such measures, as well as the cost and health 
impacts of such reductions to the extent they are known.
3. Adverse Environmental Effects
    Based on the results of our environmental risk screening 
assessment, we conclude that there is not an adverse environmental 
effect as a result of HAP emissions from the Phosphate Fertilizer 
Production source category. We are proposing that it is not necessary 
to set a more stringent standard to prevent an adverse environmental 
effect, taking into consideration costs, energy, safety and other 
relevant factors.

C. What are the results and proposed decisions based on our technology 
review for the Phosphate Fertilizer Production source category?

1. NESHAP Technology Review
    In order to fulfill our obligations under CAA section 112(d)(6), we 
conducted a technology review to identify new developments that may 
warrant revisions to the current NESHAP standards applicable to the 
Phosphate Fertilizer Production source category (i.e., NESHAP subpart 
BB). In conducting our technology review for the Phosphate Fertilizer 
Production source category, we utilized the RBLC database and the data 
submitted by facilities in response to the April 2010 CAA section 114 
request.
    Based on our review of the RBLC, we did not find any new 
developments in practices, processes and control technologies that have 
been applied since the original NESHAP to reduce emissions from 
phosphate fertilizer production plants.
    Based on our review of the CAA section 114 data (see memorandum, 
``CAA Section 111(b)(1)(B) and 112(d)(6) Reviews for the Phosphoric 
Acid Manufacturing and Phosphate Fertilizer Production Source 
Categories,'' which is available in Docket No. EPA-HQ-OAR-2012-0522), 
we determined that the control technologies used at phosphate 
fertilizer production plants have not changed since the EPA published 
the 1996 memorandum, ``National Emission Standards for Hazardous Air 
Pollutants from Phosphoric Acid Manufacturing and Phosphate Fertilizers 
Production; Proposed Rules--Draft Technical Support Document and 
Additional Technical Information,'' which is available in Docket ID No. 
A-94-02.
    In general, the Phosphate Fertilizer Production source category 
continues to use wet scrubbing technology to control HF emissions from 
the APF processes. We did not identify any technical

[[Page 66550]]

developments in wet scrubbing methods used at phosphate fertilizer 
production plants. As noted in the memorandum discussed above, the type 
and configuration of the wet scrubbing technology varies significantly 
between facilities and between process lines within a facility. In 
order to determine the differences in effectiveness of control device 
technologies we identified, we reviewed the emissions data submitted by 
facilities in response to the April 2010 and January 2014 CAA section 
114 requests.
    For APF process lines, we identified four control technology 
configurations from the CAA section 114 data. However, based on the 
available emissions data, we could not distinguish one configuration 
that clearly achieved greater emissions reductions than the other 
configurations. The emissions data for the four configurations we 
identified cover a wide range of emissions and do not show that a 
particular configuration achieves greater emission reductions. We 
believe that observed differences in facility emissions are likely the 
result of factors other than control technology (e.g., subtle 
differences in sampling and analytical techniques, age of control 
equipment and differences in facility operation).
    For TSP processes, none of the 11 facilities with APF processes 
have active operations for TSP production or storage based on the CAA 
section 114 responses. While one facility is permitted to store GTSP, 
we do not anticipate that the facility will resume GTSP operations at 
any point in the future because according to the International 
Fertilizer Industry Association, North American production of GTSP 
ceased in 2007. However, if a facility were to start producing and 
storing TSP, the control technologies would be the same as those 
already used at APF process lines because the same, or very similar, 
equipment is used to produce and store TSP as what is used to produce 
and store APF (see the 1996 memorandum, ``National Emission Standards 
for Hazardous Air Pollutants from Phosphoric Acid Manufacturing and 
Phosphate Fertilizers Production; Proposed Rules--Draft Technical 
Support Document and Additional Technical Information,'' which is 
available in Docket ID No. A-94-02). Given the lack of TSP production 
in the U.S., and the lack of new control technologies for the similarly 
controlled APF process lines, no new technologies were identified 
during this review of TSP production and storage processes.
    Therefore, neither these data nor any other information we have 
examined show that there has been a significant improvement in the add-
on control technology or other equipment since promulgation of NESHAP 
subpart BB.
    We also reviewed the CAA section 114 responses to identify any work 
practices, pollution prevention techniques and process changes at 
phosphate fertilizer production manufacturing plants that could achieve 
emission reductions. We did not identify any developments regarding 
practices, techniques, or process changes that affect point source 
emissions from this source category. See the memorandum, ``CAA Section 
111(b)(1)(B) and 112(d)(6) Reviews for the Phosphoric Acid 
Manufacturing and Phosphate Fertilizer Production Source Categories,'' 
which is available in Docket ID No. EPA-HQ-OAR-2012-0522.
    In light of the results of the technology review, we conclude that 
additional standards are not necessary pursuant to CAA section 
112(d)(6) and we are not proposing changes to NESHAP subpart BB as part 
of our technology review. We solicit comment on our proposed decision.
2. NSPS Review
    Pursuant to CAA section 111(b)(1)(B), we conducted a review to 
identify new developments that may advise revisions to the current NSPS 
standards applicable to the Phosphate Fertilizer Production source 
category (i.e., NSPS subparts V, W and X). This review considered both 
(1) whether developments in technology or other factors support the 
conclusion that a different system of emissions reduction has become 
the ``best system of emissions reduction'' and (2) whether emissions 
limitations and percent reductions beyond those required by the 
standards are achieved in practice.
a. NSPS Subpart V Review
    Based on a search of the RBLC database, CAA section 114 data, and 
other relevant sources, we did not find any new developments that have 
been applied since the original NSPS subpart V to reduce total F 
emissions from a DAP plant. Additionally, based on our review of the 
CAA section 114 data provided by this industry, we determined that the 
technologies used to control stack emissions at DAP plants have not 
changed since the original NSPS subpart V. As discussed in more detail 
in the memorandum, ``CAA Section 111(b)(1)(B) and 112(d)(6) Reviews for 
the Phosphoric Acid Manufacturing and Phosphate Fertilizer Production 
Source Categories,'' which is available in Docket ID No. EPA-HQ-OAR-
2012-0522, we observed some differences in total F emissions from DAP 
plants. However, we did not find any patterns in emissions reductions 
based on control technology used. Although we identified four control 
technology configurations that are being used at DAP plants, based on 
the available emissions data, we could not distinguish one 
configuration that clearly achieved greater emissions reductions than 
the other configurations. The emissions data for the four 
configurations we identified cover a wide range of emissions and do not 
show that a particular configuration achieves greater emission 
reductions. We believe that observed differences in facility total F 
emissions are likely the result of factors other than control 
technology (e.g., subtle differences in sampling and analytical 
techniques, age of control equipment and differences in facility 
operating parameters). Therefore, neither these data nor any other 
information we have examined show that there has been a significant 
improvement in the add-on control technology or other equipment since 
promulgation of NSPS subpart V. Finally, we also reviewed the CAA 
section 114 responses to identify any work practices, pollution 
prevention techniques and process changes at DAP plants that could 
achieve greater emission reductions than is required under the current 
NSPS. We did not identify any developments regarding practices, 
techniques, or process changes that affect point source emissions from 
DAP plants. For these reasons, we do not see any basis for concluding 
that the ``best system of emissions reduction'' has changed.
    Therefore, we are proposing that additional revisions to NSPS 
subpart V standards are not appropriate pursuant to CAA section 
111(b)(1)(B). We solicit comment on our proposed determination.
b. NSPS Subparts W and X Reviews
    As previously discussed in section V.C.1 of this preamble, none of 
the 11 facilities with APF processes have active operations for TSP 
production or storage based on the CAA section 114 responses. While one 
facility is permitted to store GTSP, we do not anticipate that the 
facility will resume GTSP operations at any point in the future 
because, according to the International Fertilizer Industry 
Association, North American production of GTSP ceased in 2007. However, 
if a facility were to start producing and storing TSP, the control

[[Page 66551]]

technologies would be the same as those already used at APF process 
lines because the same, or very similar, equipment is used to produce 
and store GTSP as what is used to produce and store APF (see the 1996 
memorandum, ``National Emission Standards for Hazardous Air Pollutants 
from Phosphoric Acid Manufacturing and Phosphate Fertilizers 
Production; Proposed Rules--Draft Technical Support Document and 
Additional Technical Information,'' which is available in Docket ID No. 
A-94-02). Given the lack of TSP production in the U.S., and the lack of 
new developments for the similarly controlled APF process lines, no new 
developments were identified during this review of TSP production and 
storage processes. For these reasons, we do not see any basis for 
concluding that the ``best system of emissions reduction'' has changed.
    Therefore, we are proposing that additional revisions to NSPS 
subpart W and subpart X standards are not appropriate pursuant to CAA 
section 111(b)(1)(B). We solicit comment on our proposed determination.

D. What other actions are we proposing for the Phosphate Fertilizer 
Production source category?

    In addition to the amendments described above, we reviewed NESHAP 
subpart BB, NSPS subpart V, NSPS subpart W and NSPS subpart X to 
determine whether we should make additional amendments. From this 
review, we are proposing several additional revisions or 
clarifications. We are proposing revisions to the SSM provisions of 
NESHAP subpart BB in order to ensure that they are consistent with the 
court decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), 
which vacated two provisions that exempted sources from the requirement 
to comply with otherwise applicable CAA section 112(d) emission 
standards during periods of SSM. In addition, we are proposing 
clarifications to the applicability of NESHAP subpart BB. We also are 
proposing various other changes to testing, monitoring, recordkeeping 
and reporting requirements in NESHAP subpart BB, NSPS subpart V, NSPS 
subpart W and NSPS subpart X. Our analyses and proposed changes related 
to these issues are discussed in this section of this preamble.
1. What are the SSM requirements?
    The United States Court of Appeals for the District of Columbia 
Circuit vacated portions of two provisions in the EPA's CAA section 112 
regulations governing the emissions of HAP during periods of SSM. 
Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 
S. Ct. 1735 (U.S. 2010). Specifically, the court vacated the SSM 
exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1) holding 
that under section 302(k) of the CAA, emissions standards or 
limitations must be continuous in nature and that the SSM exemption 
violates the CAA's requirement that some CAA section 112 standards 
apply continuously.
    We are proposing the elimination of the SSM exemption in this rule. 
Consistent with Sierra Club v. EPA, the EPA is proposing standards in 
this rule that apply at all times. We are also proposing several 
revisions to appendix A of subpart BB (the General Provisions 
Applicability Table) as is explained in more detail below. For example, 
we are proposing to eliminate the incorporation of the requirement in 
the General Provisions that the source develop an SSM plan. We also are 
proposing to eliminate and revise certain recordkeeping and reporting 
requirements related to the SSM exemption as further described below.
    The EPA has attempted to ensure that the provisions we are 
proposing to eliminate are inappropriate, unnecessary or redundant in 
the absence of the SSM exemption. We are specifically seeking comment 
on whether we have successfully done so.
    For the reasons explained below, we are proposing work practice 
standards for periods of startup and shutdown in lieu of numerical 
emission limits. CAA section 112(h)(1) states that the Administrator 
may promulgate a design, equipment or operational work practice 
standard in those cases where, in the judgment of the Administrator, it 
is not feasible to prescribe or enforce an emission standard. CAA 
section 112(h)(2)(B) further defines the term ``not feasible'' in this 
context to apply when ``the application of measurement technology to a 
particular class of sources is not practicable due to technological and 
economic limitations.''
    Startup and shutdown periods at phosphate fertilizer production 
facilities generally only last between 30 minutes to 6 hours. Because 
of the variability and the relatively short duration compared to the 
time needed to conduct a performance test, which typically requires a 
full working day, the EPA has determined that it is not feasible to 
prescribe a numerical emission standard for these periods. Furthermore, 
according to information provided by industry, it is possible that the 
feed rate (i.e., equivalent P2O5 feed) can be 
zero during startup and shutdown periods. During these periods, it is 
not feasible to consistently enforce the emission standards that are 
expressed in terms of lb of pollutant/ton of feed.
    Although we requested information on emissions and the operation of 
control devices during startup and shutdown periods in the CAA section 
114 survey issued to the Phosphoric Fertilizer Production source 
category, we did not receive any emissions data collected during a 
startup and shutdown period, and we do not expect that these data 
exist. However, based on the information for control device operation 
received in the survey, we concluded that the control devices could be 
operated normally during periods of startup or shutdown. Also, we 
believe that the emissions generated during startup and shutdown 
periods are lower than during steady-state conditions because the 
amount of feed materials introduced to the process during those periods 
is lower compared to normal operations. Therefore, if the emission 
control devices are operated during startup and shutdown, then HAP 
emissions will be the same or lower than during steady-state operating 
conditions.
    Consequently, we are proposing a work practice standard rather than 
an emissions limit for periods of startup or shutdown. Control devices 
used on the various process lines in this source category are effective 
at achieving desired emission reductions immediately upon start-up. 
Therefore, during startup and shutdown periods, we are proposing that 
sources begin operation of any control device(s) in the production unit 
prior to introducing any feed into the production unit. We are also 
proposing that sources must continue operation of the control device(s) 
through the shutdown period until all feed material has been processed 
through the production unit.
    Periods of startup, normal operations and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead they are, by 
definition sudden, infrequent and not reasonably preventable failures 
of emissions control, process or monitoring equipment. The EPA 
interprets CAA section 112 as not requiring emissions that occur during 
periods of malfunction to be factored into development of CAA section 
112 standards. Under CAA section 112, emissions standards for new 
sources must be no less stringent than the level ``achieved'' by the 
best controlled similar source and for existing sources generally must 
be no less stringent than the average emission limitation

[[Page 66552]]

``achieved'' by the best-performing 12 percent of sources in the 
category. There is nothing in CAA section 112 that directs the EPA to 
consider malfunctions in determining the level ``achieved'' by the best 
performing sources when setting emission standards. As the United 
States Court of Appeals for the District of Columbia Circuit has 
recognized, the phrase ``average emissions limitation achieved by the 
best performing 12 percent of'' sources ``says nothing about how the 
performance of the best units is to be calculated.'' Nat'l Ass'n of 
Clean Water Agencies v. EPA, 734 F.3d 1115, 1141 (D.C. Cir. 2013). 
While the EPA accounts for variability in setting emissions standards, 
nothing in section 112 requires the EPA to consider malfunctions as 
part of that analysis. A malfunction should not be treated in the same 
manner as the type of variation in performance that occurs during 
routine operations of a source. A malfunction is a failure of the 
source to perform in a ``normal or usual manner'' and no statutory 
language compels the EPA to consider such events in setting CAA section 
112 standards.
    Further, accounting for malfunctions in setting emission standards 
would be difficult, if not impossible, given the myriad different types 
of malfunctions that can occur across all sources in the category and 
given the difficulties associated with predicting or accounting for the 
frequency, degree and duration of various malfunctions that might 
occur. For these reasons, the performance of units that are 
malfunctioning is not ``reasonably'' foreseeable. See, e.g., Sierra 
Club v. EPA, 167 F. 3d 658, 662 (D.C. Cir. 1999) (the EPA typically has 
wide latitude in determining the extent of data-gathering necessary to 
solve a problem. We generally defer to an agency's decision to proceed 
on the basis of imperfect scientific information, rather than to 
``invest the resources to conduct the perfect study.''). See also, 
Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) (``In the 
nature of things, no general limit, individual permit, or even any 
upset provision can anticipate all upset situations. After a certain 
point, the transgression of regulatory limits caused by `uncontrollable 
acts of third parties,' such as strikes, sabotage, operator 
intoxication or insanity, and a variety of other eventualities, must be 
a matter for the administrative exercise of case-by-case enforcement 
discretion, not for specification in advance by regulation.''). In 
addition, emissions during a malfunction event can be significantly 
higher than emissions at any other time of source operation. For 
example, if an air pollution control device with 99 percent removal 
goes off-line as a result of a malfunction (as might happen if, for 
example, the bags in a baghouse catch fire) and the emission unit is a 
steady state type unit that would take days to shut down, the source 
would go from 99-percent control to zero control until the control 
device was repaired. The source's emissions during the malfunction 
would be 100 times higher than during normal operations, and the 
emissions over a 4-day malfunction period would exceed the annual 
emissions of the source during normal operations. As this example 
illustrates, accounting for malfunctions could lead to standards that 
are not reflective of (and significantly less stringent than) levels 
that are achieved by a well-performing non-malfunctioning source. It is 
reasonable to interpret CAA section 112 to avoid such a result. The 
EPA's approach to malfunctions is consistent with CAA section 112 and 
is a reasonable interpretation of the statute.
    In the event that a source fails to comply with the applicable CAA 
section 112 standards as a result of a malfunction event, the EPA would 
determine an appropriate response based on, among other things, the 
good-faith efforts of the source to minimize emissions during 
malfunction periods, including preventative and corrective actions, as 
well as root cause analyses to ascertain and rectify excess emissions. 
The EPA would also consider whether the source's failure to comply with 
the CAA section 112 standard was, in fact, ``sudden, infrequent, not 
reasonably preventable'' and was not instead ``caused in part by poor 
maintenance or careless operation'' 40 CFR 63.2 (definition of 
malfunction).
    If the EPA determines in a particular case that enforcement action 
against a source for violation of an emission standard is warranted, 
the source can raise any and all defenses in that enforcement action 
and the federal district court will determine what, if any, relief is 
appropriate. The same is true for citizen enforcement actions. 
Similarly, the presiding officer in an administrative proceeding can 
consider any defense raised and determine whether administrative 
penalties are appropriate.
    In summary, the EPA interpretation of the CAA and, in particular, 
CAA section 112, is reasonable and encourages practices that will avoid 
malfunctions. Administrative and judicial procedures for addressing 
exceedances of the standards fully recognize that violations may occur 
despite good faith efforts to comply and can accommodate those 
situations.
    In several prior CAA section 112 rules, the EPA had included an 
affirmative defense to civil penalties for violations caused by 
malfunctions in an effort to create a system that incorporates some 
flexibility, recognizing that there is a tension, inherent in many 
types of air regulation, to ensure adequate compliance while 
simultaneously recognizing that despite the most diligent of efforts, 
emission standards may be violated under circumstances entirely beyond 
the control of the source. Although the EPA recognized that its case-
by-case enforcement discretion provides sufficient flexibility in these 
circumstances, it included the affirmative defense to provide a more 
formalized approach and more regulatory clarity. See Weyerhaeuser Co. 
v. Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 1978) (holding that an 
informal case-by-case enforcement discretion approach is adequate); but 
see Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977) 
(requiring a more formalized approach to consideration of ``upsets 
beyond the control of the permit holder.''). Under the EPA's regulatory 
affirmative defense provisions, if a source could demonstrate in a 
judicial or administrative proceeding that it had met the requirements 
of the affirmative defense in the regulation, civil penalties would not 
be assessed. Recently, the United States Court of Appeals for the 
District of Columbia Circuit vacated an affirmative defense in one of 
the EPA's CAA section 112 regulations. NRDC v. EPA, 749 F.3d 1055 (D.C. 
Cir., 2014) (vacating affirmative defense provisions in CAA section 112 
rule establishing emission standards for Portland cement kilns). The 
court found that the EPA lacked authority to establish an affirmative 
defense for private civil suits and held that under the CAA, the 
authority to determine civil penalty amounts in such cases lies 
exclusively with the courts, not the EPA. Specifically, the court 
found: ``As the language of the statute makes clear, the courts 
determine, on a case-by-case basis, whether civil penalties are 
`appropriate.' '' See NRDC, 2014 U.S. App. LEXIS 7281 at *21 (``[U]nder 
this statute, deciding whether penalties are `appropriate' in a given 
private civil suit is a job for the courts, not EPA.'').\30\ In light 
of NRDC, the EPA is not including

[[Page 66553]]

a regulatory affirmative defense provision in the proposed rule. As 
explained above, if a source is unable to comply with emissions 
standards as a result of a malfunction, the EPA may use its case-by-
case enforcement discretion to provide flexibility, as appropriate. 
Further, as the United States Court of Appeals for the District of 
Columbia Circuit recognized, in an EPA or citizen enforcement action, 
the court has the discretion to consider any defense raised and 
determine whether penalties are appropriate. Cf. NRDC, 2014 U.S. App. 
LEXIS 7281 at *24 (arguments that violation were caused by unavoidable 
technology failure can be made to the courts in future civil cases when 
the issue arises). The same is true for the presiding officer in EPA 
administrative enforcement actions.\31\
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    \30\ The court's reasoning in NRDC focuses on civil judicial 
actions. The court noted that ``EPA's ability to determine whether 
penalties should be assessed for Clean Air Act violations extends 
only to administrative penalties, not to civil penalties imposed by 
a court.'' Id.
    \31\ Although the NRDC case does not address the EPA's authority 
to establish an affirmative defense to penalties that is available 
in administrative enforcement actions, EPA is not including such an 
affirmative defense in the proposed rule. As explained above, such 
an affirmative defense is not necessary. Moreover, assessment of 
penalties for violations caused by malfunctions in administrative 
proceedings and judicial proceedings should be consistent. CF. CAA 
section 113(e) (requiring both the Administrator and the court to 
take specified criteria into account when assessing penalties).
---------------------------------------------------------------------------

a. 40 CFR 63.628(b) General Duty
    We are proposing to revise the entry for 40 CFR 63.6(e)(1)(i) and 
(e)(1)(ii) in the General Provisions table (appendix A) by changing the 
``yes'' in column three to a ``no.'' Section 63.6(e)(1)(i) describes 
the general duty to minimize emissions. Some of the language in that 
section is no longer necessary or appropriate in light of the 
elimination of the SSM exemption. We are proposing instead to add 
general duty regulatory text at 40 CFR 63.628(b) that reflects the 
general duty to minimize emissions while eliminating the reference to 
periods covered by an SSM exemption. The current language in 40 CFR 
63.6(e)(1)(i) characterizes what the general duty entails during 
periods of SSM. With the elimination of the SSM exemption, there is no 
need to differentiate between normal operations, startup and shutdown 
and malfunction events in describing the general duty. Therefore, the 
language the EPA is proposing does not include that language from 40 
CFR 63.6(e)(1). We are also proposing to revise the entry for 40 CFR 
63.6(e)(1)(ii) in the General Provisions table (appendix A) by changing 
the ``yes'' in column three to a ``no.'' Section 63.6(e)(1)(ii) imposes 
requirements that are not necessary with the elimination of the SSM 
exemption or are redundant of the general duty requirement being added 
at 40 CFR 63.628(b).
b. SSM Plan
    We are proposing to revise the entry for 40 CFR 63.6(e)(3) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' Generally, these paragraphs require development of 
an SSM plan and specify SSM recordkeeping and reporting requirements 
related to the SSM plan. As noted, the EPA is proposing to remove the 
SSM exemptions. Therefore, affected units will be subject to an 
emission standard during such events. The applicability of a standard 
during such events will ensure that sources have ample incentive to 
plan for and achieve compliance and thus the SSM plan requirements are 
no longer necessary.
c. Compliance With Standards
    We are proposing to revise the entry for 40 CFR 63.6(f) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' The current language of 40 CFR 63.6 (f)(1) exempts 
sources from non-opacity standards during periods of SSM. As discussed 
above, the court in Sierra Club vacated the exemptions contained in 
this provision and held that the CAA requires that some CAA section 112 
standard apply continuously. Consistent with Sierra Club, the EPA is 
proposing to revise standards in this rule to apply at all times.
d. 40 CFR 63.626 Performance Testing
    We are proposing to revise the entry for 40 CFR 63.7(e)(1) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' Section 63.7(e)(1) describes performance testing 
requirements. The EPA is instead proposing to add a performance testing 
requirement at 40 CFR 63.626(d). The performance testing requirements 
we are proposing to add differ from the General Provisions performance 
testing provisions in several respects. The proposed regulatory text 
does not allow testing during startup, shutdown, or malfunction. The 
proposed regulatory does not include the language in 40 CFR 63.7(e)(1) 
that restated the SSM exemption and language that precluded startup and 
shutdown periods from being considered ``representative'' for purposes 
of performance testing. Furthermore, as in 40 CFR 63.7(e)(1), 
performance tests conducted under this subpart should not be conducted 
during malfunctions because conditions during malfunctions are often 
not representative of operating conditions.
    We are proposing that sources conduct performance tests during 
``maximum representative operating conditions for the process''. 
Specifically, we are proposing that sources must operate their process 
during the performance test in such a way that results in the flue gas 
characteristics that are the most difficult for reducing emissions of 
the regulated pollutant(s) by the control device used. In an effort to 
provide more flexibility to owners and operators regarding the 
identification of the proper testing conditions, the most difficult 
condition for the control device may include, but is not limited to, 
the highest HAP mass loading rate to the control device, or the highest 
HAP mass loading rate of constituents that approach the limits of 
solubility for scrubbing media. The EPA understands that there may be 
cases where efficiencies are dependent on other characteristics of 
emission streams, including the characteristics of components and the 
operating principles of the devices. For example, the solubility of 
emission stream components in scrubbing media, or emission stream 
component affinity in carbon adsorption systems can also define the 
most difficult condition for a particular control device. The EPA is 
also proposing to add language that requires the owner or operator to 
record the process information that is necessary to document operating 
conditions during the test and include in such record an explanation to 
support that such conditions represent maximum representative operating 
conditions. Section 63.7(e) requires that the owner or operator make 
available to the Administrator upon request such records ``as may be 
necessary to determine the condition of the performance test,'' but did 
not specifically require the owner or operator to record the 
information. The regulatory text the EPA is proposing to add builds on 
that requirement and makes explicit the requirement to record the 
information.
e. Monitoring
    We are proposing to revise the entry for 40 CFR 63.8(c)(1)(i) and 
(c)(1)(iii) in the General Provisions table by changing the ``yes'' in 
column three to a ``no.'' The cross-references to the general duty and 
SSM plan requirements in those subparagraphs are not necessary in light 
of other requirements of 40 CFR 63.8 that require good air pollution 
control practices (40 CFR 63.8(c)(1)) and that set out the requirements 
of a quality control

[[Page 66554]]

program for monitoring equipment (40 CFR 63.8(d)).
    We are proposing to revise the entry for 40 CFR 63.8(d)(3) in the 
General Provisions table by changing the ``yes'' in column three to a 
``no.'' The final sentence in 40 CFR 63.8(d)(3) refers to the General 
Provisions' SSM plan requirement, which is no longer applicable. The 
EPA is proposing to add to the rule at 40 CFR 63.628(c) text that is 
identical to 40 CFR 63.8(d)(3), except that the final sentence is 
replaced with the following sentence: ``You must include the program of 
corrective action required under Sec.  63.8(d)(2) in the plan.''
f. 40 CFR 63.627 Recordkeeping
    We are proposing to revise the entry for 40 CFR 63.10(b)(2)(i) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' Section 63.10(b)(2)(i) describes the 
recordkeeping requirements during startup and shutdown. These recording 
provisions are no longer necessary because the EPA is proposing that 
recordkeeping and reporting applicable to normal operations will apply 
to startup and shutdown. In the absence of special provisions 
applicable to startup and shutdown, such as a startup and shutdown 
plan, there is no reason to retain additional recordkeeping for startup 
and shutdown periods.
    We are proposing to revise the entry for 40 CFR 63.10(b)(2)(ii) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' Section 63.10(b)(2)(ii) describes the 
recordkeeping requirements during a malfunction. The EPA is proposing 
to add such requirements to 40 CFR 63.627(b). The regulatory text we 
are proposing to add differs from the General Provisions it is 
replacing in that the General Provisions requires the creation and 
retention of a record of the occurrence and duration of each 
malfunction of process, air pollution control and monitoring equipment. 
The EPA is proposing that this requirement apply to any failure to meet 
an applicable standard and is requiring that the source record the 
date, time and duration of the failure rather than the ``occurrence.'' 
The EPA is also proposing to add to 40 CFR 63.627 a requirement that 
sources keep records that include a list of the affected source or 
equipment and actions taken to minimize emissions, an estimate of the 
volume of each regulated pollutant emitted over the applicable 
standard, and a description of the method used to estimate the 
emissions. Examples of such methods would include product-loss 
calculations, mass balance calculations, measurements when available or 
engineering judgment based on known process parameters. The EPA is 
proposing to require that sources keep records of this information to 
ensure that there is adequate information to allow the EPA to determine 
the severity of any failure to meet a standard, and to provide data 
that may document how the source met the general duty to minimize 
emissions when the source has failed to meet an applicable standard.
    We are proposing to revise the entry for 40 CFR 63.10(b)(2)(iv) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' When applicable, the provision requires 
sources to record actions taken during SSM events when actions were 
inconsistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required. The 
requirement previously applicable under 40 CFR 63.10(b)(2)(iv)(B) to 
record actions to minimize emissions and record corrective actions is 
now applicable by reference to 40 CFR 63.627.
    We are proposing to revise the entry for 40 CFR 63.10(b)(2)(v) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' When applicable, the provision requires 
sources to record actions taken during SSM events to show that actions 
taken were consistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required.
    We are proposing to revise the entry for 40 CFR 63.10(c)(15) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' The EPA is proposing that 40 CFR 63.10(c)(15) no 
longer apply. When applicable, the provision allows an owner or 
operator to use the affected source's SSM plan or records kept to 
satisfy the recordkeeping requirements of the SSM plan, specified in 40 
CFR 63.6(e), to also satisfy the requirements of 40 CFR 63.10(c)(10) 
through (12). The EPA is proposing to eliminate this requirement 
because SSM plans would no longer be required, and, therefore, 40 CFR 
63.10(c)(15) no longer serves any useful purpose for affected units.
g. 40 CFR 63.627 Reporting
    We are proposing to revise the entry for 40 CFR 63.10(d)(5) in the 
General Provisions table (appendix A) by changing the ``yes'' in column 
three to a ``no.'' Section 63.10(d)(5) describes the reporting 
requirements for SSM. To replace the General Provisions reporting 
requirement, the EPA is proposing to add reporting requirements to 40 
CFR 63.627. The replacement language differs from the General 
Provisions requirement in that it eliminates periodic SSM reports as a 
stand-alone report. We are proposing language that requires sources 
that fail to meet an applicable standard at any time to report the 
information concerning such events in the excess emission report, 
already required under this rule. We are proposing that the report must 
contain the number, date, time, duration and the cause of such events 
(including unknown cause, if applicable), a list of the affected source 
or equipment, an estimate of the volume of each regulated pollutant 
emitted over any emission limit and a description of the method used to 
estimate the emissions (e.g., product-loss calculations, mass balance 
calculations, direct measurements, or engineering judgment based on 
known process parameters). The EPA is proposing this requirement to 
ensure that adequate information is available to determine compliance, 
to allow the EPA to determine the severity of the failure to meet an 
applicable standard, and to provide data that may document how the 
source met the general duty to minimize emissions during a failure to 
meet an applicable standard.
    The proposed rule eliminates the cross reference to 40 CFR 
63.10(d)(5)(i) that contains the description of the previously-required 
SSM report format and submittal schedule from this section. These 
specifications are no longer necessary because the events will be 
reported in otherwise required reports with similar format and 
submittal requirements. We are proposing that owners or operators no 
longer be required to determine whether actions taken to correct a 
malfunction are consistent with an SSM plan because the plans would no 
longer be required.
    We are proposing to revise the entry for 40 CFR 63.10(d)(5)(ii) in 
the General Provisions table (appendix A) by changing the ``yes'' in 
column three to a ``no.'' Section 63.10(d)(5)(ii) describes an 
immediate report for SSM when a source failed to meet an applicable 
standard but did not follow the SSM plan. We will no longer require 
owners and operators to report when actions taken during a startup, 
shutdown or malfunction were not consistent with an SSM plan, because 
the plans would no longer be required.
2. Clarifications to Applicability and Certain Definitions
a. NESHAP Subpart BB
    We are proposing clarifications to the applicability section (40 
CFR 63.620) of the Phosphate Fertilizer Production

[[Page 66555]]

NESHAP (subpart BB). The requirements of the current Phosphate 
Fertilizer Production NESHAP (subpart BB) apply to diammonium and/or 
monoammonium phosphate process lines, granular triple superphosphate 
lines and granular triple superphosphate storage buildings only. In 
this action, we are proposing clarifications to the applicability of 
the NESHAP to include any process line that produces a reaction product 
of ammonia and phosphoric acid. Based on facility responses to the CAA 
section 114 survey issued to the Phosphate Fertilizer Production source 
category, EPA learned that the phosphate fertilizer products produced 
by facilities changes over time (e.g., no facility currently produces a 
granular triple superphosphate product). To ensure the emission 
standards we are proposing reflect inclusion of HAP emissions from all 
sources in the defined source category, as initially intended in the 
rule promulgation, we believe it necessary to clarify the applicability 
of the NESHAP to include reaction products of ammonia and phosphoric 
acid, and not just diammonium and monoammonium phosphate. This revision 
also further aligns the definition of the source category with the 
current provisions in 40 CFR 63.620(a) which specify that the NESHAP 
applies to each phosphate fertilizers production plant.
    Granular triple superphosphate is no longer produced in the United 
States. However, in the unlikely event that a facility were to start 
producing and storing GTSP, we are not proposing to remove requirements 
for the triple superphosphate processes regulated by NESHAP subpart BB 
(i.e., GTSP process lines and storage buildings).
    For consistency between NESHAP subpart AA and NESHAP subpart BB, we 
are proposing the NESHAP subpart AA conditions that exclude the use of 
evaporative cooling towers for any liquid effluent from any wet 
scrubbing device installed to control HF emissions from process 
equipment also be included in NESHAP subpart BB. For additional 
consistency between NESHAP subpart AA and NESHAP subpart BB, we are 
also proposing to amend the definitions of diammonium and/or 
monoammonium phosphate process line, granular triple superphosphate 
process line and granular triple superphosphate storage building to 
include relevant emission points, and to remove text from the 
applicability section that is duplicative of the revised definitions.
b. NSPS Subpart W
    We are proposing to change the word ``cookers'' as listed in 40 CFR 
60.230(a) to ``coolers'' in order to correct the typographical error. 
The term should be ``coolers,'' and background literature does not 
indicate any equipment referred to ``cookers'' being used in the 
manufacture of TSP.
3. Testing, Monitoring, Recordkeeping and Reporting
a. NESHAP Subpart BB
    For wet scrubbers, we are proposing alternatives to the existing 
requirement to monitor pressure differential through the scrubber. We 
received input from industry that the pressure differential is not a 
reliable method of determining the performance of a column because 
fouling occurs over time, increasing the pressure differential. The 
pressure differential immediately after cleaning will be much lower 
than that after the scrubber has operated for some time. Therefore, to 
provide flexibility, we have included a number of monitoring options as 
alternatives to determining the performance of a column using pressure 
differential. We are also adding flexibility in the existing 
requirement to measure the flow rate of the scrubbing liquid to each 
scrubber (i.e., the inlet liquid flow rate to a scrubber). We are 
proposing that the inlet liquid-to-gas ratio may now be monitored in 
lieu of the inlet liquid flow rate, which provides the ability to lower 
liquid flow rate with changes in gas flow rate to the scrubber.
    We are removing the requirement that facilities may not implement 
new operating parameter ranges until the Administrator has approved 
them, or 30 days have passed since submission of the performance test 
results. For the proposed requirements, facilities must immediately 
comply with new operating ranges when they are developed and submitted. 
New operating ranges must also be established using the most recent 
performance test conducted by a facility, which allows for changes in 
control device operation to be appropriately reflected.
    As described in section V.D.1.d of this preamble, we have also 
modified the language for the conditions under which testing must be 
conducted to require that testing be conducted at maximum 
representative operating conditions for the process.
    For subpart BB we are proposing monitoring requirements for fabric 
filters because two processes were identified that used fabric filters 
rather than wet scrubbing as the control technology.
    In keeping with the general provisions for CMS (including CEMS and 
CPMS), we are proposing the addition of a site-specific monitoring plan 
and calibration requirements for CMS. Provisions are included for 
electronic reporting of stack test data.
    We have also modified the format of the NESHAP to reference tables 
for emissions limits and monitoring requirements.
b. NSPS Subpart V
    The EPA evaluated the monitoring and recordkeeping requirements 
currently required in NSPS subpart V to determine if they are adequate 
for determining compliance. Currently under NSPS subpart V, an owner or 
operator of a granular diammonium phosphate plant is required to 
install, calibrate, maintain and operate a monitoring device which 
continuously measures and permanently records the total pressure drop 
across the process scrubbing system. However, the current rule does not 
require an owner or operator to establish, and demonstrate continuous 
compliance with, an allowable range for the pressure drop through the 
process scrubbing system. Therefore, we are proposing new monitoring 
and recordkeeping requirements for any diammonium phosphate plant that 
commences construction, modification or reconstruction after [date of 
publication of the final rule in the Federal Register] to ensure 
continuous compliance with the standard.
    We are proposing that for any granular diammonium phosphate plant 
that commences construction, modification or reconstruction after [date 
of publication of the final rule in the Federal Register] the owner or 
operator establish an allowable range for the pressure drop through the 
process scrubbing system. The allowable range would be established 
during the performance test required in 40 CFR 60.8. We also propose 
that the allowable range is 20 percent of the arithmetic 
average of the three test runs conducted during the performance test. 
In addition, the owner or operator would be required to maintain the 
daily average pressure drop through the process scrubbing system within 
the allowable range; and valid data points must be available for 75 
percent of the operating hours in an operating day to compute the daily 
average. We also propose that the owner or operator keep records of the 
daily average pressure drop through the process scrubbing system, and 
keep records of deviations. We are proposing

[[Page 66556]]

these monitoring and recordkeeping requirements in order to: Ensure 
that the process scrubbing system is properly maintained over time; 
ensure continuous compliance with standards; and improve data 
accessibility.
    Finally, for consistency with terminology used in the associated 
NESHAP subpart BB, we have changed the term ``process scrubbing 
system'' to ``absorber''.
    We do not expect any costs to be associated with these proposed 
monitoring and recordkeeping requirements. These proposed requirements 
will apply to all diammonium phosphate plants that reconstruct or 
modify their plants; however, facilities that are subject to the NESHAP 
are exempt from compliance with the NSPS. We are aware of only one 
facility currently subject to the NSPS, but not the NESHAP. We do not 
anticipate that this facility will modify their diammonium phosphate 
plant over the next 3 years; therefore, this facility will not trigger 
the proposed monitoring and recordkeeping requirements for NSPS subpart 
V. Furthermore, pursuant to their Title V air permit compliance 
assurance monitoring plan, this facility already conducts daily 
monitoring of pressure drop through their process scrubbing system and 
compares it against an established range. Therefore, any costs to 
comply with these requirements would be negligible should the facility 
become subject.
c. NSPS Subpart W
    The EPA evaluated the monitoring and recordkeeping requirements 
currently required in NSPS subpart W to determine if they are adequate 
for determining compliance. Currently under NSPS subpart W, an owner or 
operator of a triple superphosphate plant is required to install, 
calibrate, maintain and operate a monitoring device which continuously 
measures and permanently records the total pressure drop across the 
process scrubbing system. However, the current rule does not require an 
owner or operator to establish, and demonstrate continuous compliance 
with, an allowable range for the pressure drop through the process 
scrubbing system. Therefore, we are proposing new monitoring and 
recordkeeping requirements for any triple superphosphate plant that 
commences construction, modification or reconstruction after [date of 
publication of the final rule in the Federal Register] to ensure 
continuous compliance with the standard.
    We are proposing that for any triple superphosphate plant that 
commences construction, modification or reconstruction after [date of 
publication of the final rule in the Federal Register] the owner or 
operator establish an allowable range for the pressure drop through the 
process scrubbing system. The allowable range would be established 
during the performance test required in 40 CFR 60.8. We also propose 
that the allowable range is 20 percent of the arithmetic 
average of the three test runs conducted during the performance test. 
In addition, the owner or operator would be required to maintain the 
daily average pressure drop through the process scrubbing system within 
the allowable range; and valid data points must be available for 75 
percent of the operating hours in an operating day to compute the daily 
average. We also propose that the owner or operator keep records of the 
daily average pressure drop through the process scrubbing system, and 
keep records of deviations. We are proposing these monitoring and 
recordkeeping requirements in order to: Ensure that the process 
scrubbing system is properly maintained over time; ensure continuous 
compliance with standards; and improve data accessibility.
    Finally, for consistency with terminology used in the associated 
NESHAP subpart BB, we have changed the term ``process scrubbing 
system'' to ``absorber.''
    We do not expect any costs associated with these proposed 
monitoring and recordkeeping requirements, as we are not aware of any 
facilities in the United States that manufacture TSP or that plan to 
manufacture TSP in the next three years.
d. NSPS Subpart X
    The EPA evaluated the monitoring and recordkeeping requirements 
currently required in NSPS subpart X to determine if they are adequate 
for determining compliance. Currently under NSPS subpart X, an owner or 
operator of a granular triple superphosphate storage facility is 
required to install, calibrate, maintain and operate a monitoring 
device which continuously measures and permanently records the total 
pressure drop across the process scrubbing system. However, the current 
rule does not require an owner or operator to establish, and 
demonstrate continuous compliance with, an allowable range for the 
pressure drop through the process scrubbing system. Therefore, we are 
proposing new monitoring and recordkeeping requirements for any 
granular triple superphosphate storage facility that commences 
construction, modification or reconstruction after [date of publication 
of the final rule in the Federal Register] to ensure continuous 
compliance with the standard.
    We are proposing that for any granular triple superphosphate 
storage facility that commences construction, modification or 
reconstruction after [date of publication of the final rule in the 
Federal Register] the owner or operator establish an allowable range 
for the pressure drop through the process scrubbing system. The 
allowable range would be established during the performance test 
required in 40 CFR 60.8. We also propose that the allowable range is 
20 percent of the arithmetic average of the three test runs 
conducted during the performance test. In addition, the owner or 
operator would be required to maintain the daily average pressure drop 
through the process scrubbing system within the allowable range; and 
valid data points must be available for 75 percent of the operating 
hours in an operating day to compute the daily average. We also propose 
that the owner or operator keep records of the daily average pressure 
drop through the process scrubbing system, and keep records of 
deviations. We are proposing these monitoring and recordkeeping 
requirements in order to: Ensure that the process scrubbing system is 
properly maintained over time; ensure continuous compliance with 
standards; and improve data accessibility.
    Finally, for consistency with terminology used in the associated 
NESHAP subpart BB, we have changed the term ``process scrubbing 
system'' to ``absorber.''
    We do not expect any costs associated with these proposed 
monitoring and recordkeeping requirements as we are not aware of any 
facilities that manufacture or store GTSP or plan to manufacture or 
store GTSP in the next 3 years.
4. Translation of TF to HF Emission Limits
    As described in section IV.E.4 of this preamble, the EPA is 
proposing to translate the current total F limit (lbs total F/ton 
P2O5 feed) into an HF limit (lbs HF/ton 
P2O5 feed). Please refer to section IV.E.4 of 
this preamble for a detailed description of the methodology used to 
translate the existing TF limits to HF limits.
    The resulting new and existing proposed HF emission limits are 
summarized in Table 8 of this preamble:

[[Page 66557]]



      Table 8--Summary of Proposed HF Emission Limits for New and Existing Phosphate Fertilizer Facilities
----------------------------------------------------------------------------------------------------------------
                                            Current total F limits *                Proposed HF limits *
          Regulated process          ---------------------------------------------------------------------------
                                           Existing             New              Existing             New
----------------------------------------------------------------------------------------------------------------
MAP/DAP Fertilizer Lines............              0.060             0.0580              0.060             0.0580
GTSP Process Line...................              0.150             0.1230              0.150             0.1230
GTSP Storage Building...............       5.0 x 10-\4\       5.0 x 10-\4\       5.0 x 10-\4\       5.0 x 10-\4\
----------------------------------------------------------------------------------------------------------------
* All limits expressed as lbs/Ton P2O5 feed.

    Also, as discussed in section IV.E.4 of this preamble, we are 
seeking comment on finalizing HF limits for regulating HF rather than 
total F, the use of EPA Method 320 for the compliance demonstration 
test method, the use of FTIR HF CEMS as an optional continuous 
monitoring compliance approach within the rule, the use of an HF CEMS 
as a compliance option and reduced testing frequency for HF monitoring. 
A more detailed discussion of these requests for comments is provided 
in section IV.E.4 of this preamble.

E. What are the notification, recordkeeping and reporting requirements 
for the Phosphate Fertilizer Production source category?

    For the Phosphate Fertilizer Production source category, we are 
proposing the same electronic reporting requirements described in 
section IV.F of this preamble.

F. What compliance dates are we proposing for the Phosphate Fertilizer 
Production source category?

    We are proposing that for existing and new process lines that 
produce a reaction product of ammonia and phosphoric acid (e.g., 
diammonium and/or monoammonium phosphate process lines), granular 
triple superphosphate process lines and granular triple superphosphate 
storage buildings that commence construction or reconstruction on or 
before the effective date of this rule, the facility must comply with 
the proposed HF limits no later than 1 year after the effective date of 
this rule. Facilities will continue to conduct the annual performance 
test, but will be required to use a different test method. Therefore, 
we are proposing a 1-year compliance lead time so that facilities have 
adequate time to coordinate performance testing with the new test 
method. We do not anticipate that any facilities will need to install a 
new control device to meet the proposed HF limits. For new process 
lines that produce a reaction product of ammonia and phosphoric acid 
(e.g., diammonium and/or monoammonium phosphate process lines), 
granular triple superphosphate process lines and granular triple 
superphosphate storage buildings that commence construction or 
reconstruction after the effective date of this rule, the facility must 
comply with the proposed HF limits beginning on the effective date of 
this rule. Prior to these compliance dates (for HF limits), we are 
proposing that facilities continue to comply with the current total F 
standards.
    We are proposing that the SSM requirements compliance date is the 
effective date of this rule.

VI. Summary of Cost, Environmental and Economic Impacts

A. What are the affected sources?

    We anticipate that the 13 facilities currently operating in the 
United States will be affected by these proposed amendments. One of the 
13 facilities has indicated to the EPA that it plans on closing the 
phosphoric acid and phosphate fertilizer processes when the gypsum 
dewatering stack in use reaches the end of its capacity to accept 
gypsum slurry. We do not expect any new facilities to be constructed or 
expanded in the foreseeable future.

B. What are the air quality impacts?

    We have estimated the potential emissions reductions that may be 
realized from the implementation of the proposed emission standards for 
the Phosphoric Acid Manufacturing and Phosphate Fertilizer Production 
source categories. We estimated emission reductions by first 
calculating emissions at the current level of control for each facility 
(referred to as the baseline level of control), and at the proposed 
level of control (i.e., the proposed beyond-the-floor emission standard 
for Hg from phosphate rock calciners). We calculated emission 
reductions as the difference between the proposed level and baseline 
level of control. We estimate that the proposed subpart AA NESHAP will 
result in emissions reductions of approximately 145 lb per year of Hg 
from phosphate rock calciners as a result of beyond-the-floor emission 
standards for Hg. The current estimated Hg emissions from the phosphate 
rock calciners is approximately 169 lb per year. The memorandum, 
``Beyond-the-Floor Analysis for Phosphate Rock Calciners at Phosphoric 
Acid Manufacturing Plants,'' which is available in the docket for this 
action, documents the results of the beyond-the-floor analysis.

C. What are the cost impacts?

    We have estimated compliance costs for all existing sources to add 
the necessary controls and monitoring devices, perform inspections, 
recordkeeping and reporting requirements to comply with the proposed 
rule. Based on this analysis, we anticipate an overall total capital 
investment of $4.9 million, with an associated total annualized cost of 
approximately $2.0 million (using a discount rate of 7 percent), in 
2013 dollars. We do not anticipate the construction of any new 
phosphoric acid manufacturing plants or phosphate fertilizer production 
facilities in the next 5 years. Therefore, there are no new source cost 
impacts.
    We calculated costs to meet the proposed level of control. For 
phosphate rock calciners, we estimated the cost of adding a fixed-bed 
carbon adsorption system to meet the proposed Hg emission standard. For 
all other emission sources, including phosphate rock calciners, we 
calculated capital and annual costs for testing, monitoring, 
recordkeeping and reporting. The memorandum, ``Control Costs and 
Emissions Reductions for Phosphoric Acid and Phosphate Fertilizer 
Production Source Categories,'' which is available in the docket for 
this action, documents the control cost analyses.

D. What are the economic impacts?

    Economic impact analyses focus on changes in market prices and 
output levels. If changes in market prices and output levels in the 
primary markets are significant enough, we also examine impacts on 
other markets. Both the magnitude of costs needed to comply with the 
rule and the distribution of these costs among affected facilities can 
have a role in determining how the market will change in response to 
the rule. We estimated the total annualized

[[Page 66558]]

costs for the proposed rule to be $2.0 million. We project that only 
one facility will incur significant costs. A global agrochemical 
company with annual revenue estimated in the $100 million to $500 
million range owns this facility. The facility itself would not be a 
small business even if it were not owned by the larger entity. The 
annualized control costs for this company would be 0.3 percent to 1.5 
of percent revenues. We do not expect these small costs to result in a 
significant market impact whether they are passed on to the consumer or 
absorbed by the company.
    Because no small firms will incur control costs, there is no 
significant impact on small entities. Thus, we do not expect this 
regulation to have a significant impact on a substantial number of 
small entities.

E. What are the benefits?

    We anticipate this rulemaking to reduce Hg emissions by 
approximately 145 lb each year starting in 2016. These avoided 
emissions will result in improvements in air quality and reduced 
negative health effects associated with exposure to air pollution of 
these emissions; however, we have not quantified or monetized the 
benefits of reducing these emissions for this rulemaking because the 
estimated costs for this action are less than $100 million.

VII. Request for Comments

    We solicit comments on all aspects of this proposed action. In 
addition to general comments on this proposed action, we are also 
interested in additional data that may improve the risk assessments and 
other analyses. We are specifically interested in receiving any 
improvements to the data used in the site-specific emissions profiles 
used for risk modeling, including information on the appropriate acute 
emissions factors for estimating emissions from the gypsum dewatering 
stacks and cooling ponds. Such data should include supporting 
documentation in sufficient detail to allow characterization of the 
quality and representativeness of the data or information. Section VIII 
of this preamble provides more information on submitting data.

VIII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category 
risk and demographic analyses and instructions are available for 
download on the RTR Web page at: https://www.epa.gov/ttn/atw/rrisk/rtrpg.html. The data files include detailed information for each HAP 
emissions release point for the facilities in the source category.
    If you believe that the data are not representative or are 
inaccurate, please identify the data in question, provide your reason 
for concern and provide any ``improved'' data that you have, if 
available. When you submit data, we request that you provide 
documentation of the basis for the revised values to support your 
suggested changes. To submit comments on the data downloaded from the 
RTR Web page, complete the following steps:
    1. Within this downloaded file, enter suggested revisions to the 
data fields appropriate for that information.
    2. Fill in the commenter information fields for each suggested 
revision (i.e., commenter name, commenter organization, commenter email 
address, commenter phone number and revision comments).
    3. Gather documentation for any suggested emissions revisions 
(e.g., performance test reports, material balance calculations, etc.).
    4. Send the entire downloaded file with suggested revisions in 
Microsoft[supreg] Access format and all accompanying documentation to 
Docket ID Number EPA-HQ-OAR-2012-0522 (through one of the methods 
described in the ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or multiple 
facilities, you need only submit one file for all facilities. The file 
should contain all suggested changes for all sources at that facility. 
We request that all data revision comments be submitted in the form of 
updated Microsoft[supreg] Excel files that are generated by the 
Microsoft[supreg] Access file. These files are provided on the RTR Web 
page at: https://www.epa.gov/ttn/atw/rrisk/rtrpg.html.

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is not a ``significant regulatory action'' under the 
terms of Executive Order 12866 (58 FR 51735, October 4, 1993) and is, 
therefore, not subject to review under Executive Orders 12866 and 13563 
(76 FR 3821, January 21, 2011). The EPA analyzed the potential costs 
and benefits associated with this action. The results are presented in 
sections VI.C and E of this preamble.

B. Paperwork Reduction Act

    The information collection requirements in this proposed rule have 
been submitted for approval to OMB under the Paperwork Reduction Act, 
44 U.S.C. 3501, et seq. The Information Collection Request (ICR) 
document prepared by the EPA has been assigned EPA ICR number 1790.06. 
The information requirements are based on notification, recordkeeping 
and reporting requirements in the NESHAP General Provisions (40 CFR 
part 63, subpart A), which are mandatory for all operators subject to 
national emissions standards. These recordkeeping and reporting 
requirements are specifically authorized by section 114 of the CAA (42 
U.S.C. 7414). All information submitted to the EPA pursuant to the 
recordkeeping and reporting requirements for which a claim of 
confidentiality is made is safeguarded according to EPA policies set 
forth in 40 CFR part 2, subpart B.
    We are proposing new paperwork requirements to the Phosphoric Acid 
Manufacturing and Phosphate Fertilizer Production source categories in 
the form of additional requirements for stack testing, performance 
evaluations, and gypsum dewatering stacks.
    We estimate 12 regulated entities are currently subject to 40 CFR 
part 63 subpart AA and 10 regulated entities are currently subject to 
40 CFR part 63 subpart BB and each will be subject to all applicable 
proposed standards. The annual monitoring, reporting and recordkeeping 
burden for these amendments to subpart AA and BB is estimated to be 
$625,000 per year (averaged over the first 3 years after the effective 
date of the standards). This includes 640 labor hours per year at a 
total labor cost of $53,000 per year, and total non-labor capital and 
operating and maintenance costs of $572,000 per year. This estimate 
includes performance tests, notifications, reporting and recordkeeping 
associated with the new requirements for emission points and associated 
control devices. The total burden to the federal government is 
estimated to be 326 hours per year at a total labor cost of $17,000 per 
year (averaged over the first 3 years after the effective date of the 
standard). Burden is defined at 5 CFR 1320.3(b).
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    To comment on the agency's need for this information, the accuracy 
of the provided burden estimates and any suggested methods for 
minimizing respondent burden, the EPA has established a public docket 
for this rule

[[Page 66559]]

(Docket ID No. EPA-HQ-OAR-2012-0522) which includes this ICR. Submit 
any comments related to the ICR to the EPA and OMB. See ADDRESSES 
section at the beginning of this notice for where to submit comments to 
the EPA. Send comments to OMB at the Office of Information and 
Regulatory Affairs, Office of Management and Budget, 725 17th Street, 
NW., Washington, DC 20503, Attention: Desk Office for the EPA. Since 
OMB is required to make a decision concerning the ICR between 30 and 60 
days after November 7, 2014, a comment to OMB is best assured of having 
its full effect if OMB receives it by December 8, 2014. The final rule 
will respond to any OMB or public comments on the information 
collection requirements contained in this proposal.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations and small governmental jurisdictions.
    For purposes of assessing the impacts of this rule on small 
entities, small entity is defined as: (1) A small business as defined 
by the Small Business Administration's (SBA) regulations at 13 CFR 
121.201; (2) a small governmental jurisdiction that is a government of 
a city, county, town, school district or special district with a 
population of less than 50,000; and (3) a small organization that is 
any not-for-profit enterprise that is independently owned and operated 
and is not dominant in its field.
    After considering the economic impacts of this proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. This 
proposed rule will not impose any requirements on small entities 
because we do not project that any small entities will incur costs due 
to these proposed rule amendments. We continue to be interested in the 
potential impacts of the proposed rule on small entities and welcome 
comments on issues related to such impacts.

D. Unfunded Mandates Reform Act

    This action contains no federal mandates under the provisions of 
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2 U.S.C. 
1531-1538 for state, local, or tribal governments or the private 
sector. The action imposes no enforceable duty on any state, local, or 
tribal governments or the private sector. Therefore, this action is not 
subject to the requirements of sections 202 or 205 of the UMRA.
    This action is also not subject to the requirements of section 203 
of UMRA because it does not contain regulatory requirements that might 
significantly or uniquely affect small governments because this action 
neither contains requirements that apply to such governments nor does 
it impose obligations upon them.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states or on the distribution of power 
and responsibilities among the various levels of government, as 
specified in Executive Order 13132. None of the facilities subject to 
this action are owned or operated by state governments, and nothing in 
this proposal will supersede state regulations. Thus, Executive Order 
13132 does not apply to this action.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between the EPA and state and local 
governments, the EPA specifically solicits comment on this proposed 
rule from state and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    Subject to the Executive Order 13175 (65 FR 67249, November 9, 
2000), the EPA may not issue a regulation that has tribal implications, 
that imposes substantial direct compliance costs and that is not 
required by statute, unless the federal government provides the funds 
necessary to pay the direct compliance costs incurred by tribal 
governments, or the EPA consults with tribal officials early in the 
process of developing the proposed regulation and develops a tribal 
summary impact statement.
    The EPA has concluded that this action may have tribal 
implications, due to the close proximity of one facility to a tribe 
(the Shoshone-Bannock). However, this action will neither impose 
substantial direct compliance costs on tribal governments, nor preempt 
tribal law.
    The EPA consulted with tribal officials early in the process of 
developing this regulation to permit them to have meaningful and timely 
input into its development. The agency provided an overview of the 
source categories and rulemaking process during a monthly 
teleconference with the National Tribal Air Association. Additionally, 
we provided targeted outreach, including a visit to the Shoshone-
Bannock tribe and meeting with environmental leaders for the tribe. The 
EPA specifically solicits additional comment on this proposed action 
from tribal officials.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    This action is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because it is not economically significant as defined 
in Executive Order 12866. This action's health and risk assessments are 
contained in section V of this preamble.
    The proposed standards for Hg emissions from phosphate rock 
calciners will reduce Hg emissions, thereby reducing potential exposure 
to children, including the unborn. We invite the public to submit 
comments or identify peer-reviewed studies and data that assess effects 
of early life exposure to these pollutants.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy action'' as defined in 
Executive Order 13211 (66 FR 28355 (May 22, 2001)), because it is not 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy. The proposed changes to the emissions 
limits may require one facility to install additional control for Hg in 
the form of carbon adsorbers or ACI. These devices have minimal energy 
requirements, and we do not expect these devices to contribute 
significantly to the overall energy use at the facility. We have 
concluded that this rule is not likely to have any adverse energy 
effects.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law Number 104-113, 12(d) (15 U.S.C. 272 
note) directs the EPA to use voluntary consensus standards (VCS) in its 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. VCS are technical standards 
(e.g., materials specifications, test methods, sampling procedures and 
business practices) that

[[Page 66560]]

are developed or adopted by VCS bodies. The NTTAA directs the EPA to 
provide Congress, through OMB, explanations when the agency decides not 
to use available and applicable VCS.
    This proposed rulemaking involves technical standards. The EPA 
proposes to incorporate analytical methods of the Association of 
Official Analytical Chemists (AOAC) and of the Association of 
Fertilizer and Phosphate Chemists (AFPC). The EPA proposes to 
incorporate by reference the following AOAC methods: AOAC Official 
Method 957.02 Phosphorus (Total) in Fertilizers, Preparation of Sample 
Solution, AOAC Official Method 929.01 Sampling of Solid Fertilizers, 
AOAC Official Method 929.02 Preparation of Fertilizer Sample, AOAC 
Official Method 978.01 Phosphorous (Total) in Fertilizers, Automated 
Method, AOAC Official Method 969.02 Phosphorous (Total) in Fertilizers, 
Alkalimetric Quinolinium Molybdophosphate Method, AOAC Official Method 
962.02 Phosphorous (Total) in Fertilizers, Gravimetric Quinolinium 
Molybdophosphate Method and Quinolinium Molybdophosphate Method 958.01 
Phosphorous (Total) in Fertilizers, Spectrophotometric 
Molybdovanadophosphate Method. The EPA proposes to incorporate the 
following AFPC methods for analysis of phosphate rock: No. 1 
Preparation of Sample, No. 3 Phosphorus-P2O5 or Ca3(PO4)2, Method A-
Volumetric Method, No. 3 Phosphorus-P2O5 or Ca3(PO4)2, Method B-
Gravimetric Quimociac Method, No. 3 Phosphorus-P2O5 or Ca3(PO4)2, 
Method C-Spectrophotometric Method. The EPA proposes to incorporate the 
following AFPC methods for analysis of phosphoric acid, superphosphate, 
triple superphosphate and ammonium phosphates: No. 3 Total Phosphorus-
P2O5, Method A-Volumetric Method, No. 3 Total Phosphorus-P2O5, Method 
B-Gravimetric Quimociac Method and No. 3 Total Phosphorus-P2O5, Method 
C-Spectrophotometric Method.
    We did not identify any applicable VCS for EPA Methods 5, 13A, 13B 
or 30B. We did identify one VCS, ASTM D6348-03(2010), as an acceptable 
alternative for Method 320.
    During EPA's VCS search, if the title or abstract (if provided) of 
the VCS described technical sampling and analytical procedures that are 
similar to the EPA's reference method, the EPA ordered a copy of the 
standard and reviewed it as a potential equivalent method. We reviewed 
all potential standards to determine the practicality of the VCS for 
this rule. This review requires significant method validation data that 
meet the requirements of EPA Method 301 for accepting alternative 
methods or scientific, engineering and policy equivalence to procedures 
in EPA reference methods. The EPA may reconsider determinations of 
impracticality when additional information is available for particular 
VCS.
    The search identified 8 other VCS that were potentially applicable 
for this rule in lieu of the EPA reference methods. After reviewing the 
available standards, the EPA determined that 8 candidate VCS identified 
for measuring emissions of pollutants or their surrogates subject to 
emission standards in the rule would not be practical due to lack of 
equivalency, documentation, validation data and other important 
technical and policy considerations. Additional information for the VCS 
search and determinations can be found in the memorandum, ``Voluntary 
Consensus Standard Results for Phosphoric Acid Manufacturing and 
Phosphate Fertilizer Production RTR and Standards of Performance for 
Phosphate Processing,'' which is available in the docket for this 
action.
    The EPA welcomes comments on this aspect of the proposed 
rulemaking, and, specifically, invites the public to identify 
potentially applicable VCS, and to explain why the EPA should use such 
standards in this regulation.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations.

    Executive Order 12898 (59 FR 7629, February 16, 1994) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practical and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies and activities on minority populations and low-income 
populations in the United States.
    The EPA has determined that this proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority, low-income or indigenous populations because it 
increases the level of environmental protection for all affected 
populations without having any disproportionately high and adverse 
human health or environmental effects on any population, including any 
minority or low-income population. To gain a better understanding of 
the source category and near source populations, the EPA conducted a 
proximity analysis on phosphate facilities to identify any 
overrepresentation of minority, low income or indigenous populations. 
This analysis only gives some indication of the prevalence of sub-
populations that may be exposed to air pollution from the sources; it 
does not identify the demographic characteristics of the most highly 
affected individuals or communities, nor does it quantify the level of 
risk faced by those individuals or communities. More information on the 
source categories risk can be found in section IV of this preamble.
    The proximity analysis reveals that most demographic categories are 
below or within 20 percent of their corresponding national averages. 
The two exceptions are the minority and African American populations. 
The ratio of African Americans living within 3 miles of any source 
affected by this rule is 131 percent higher than the national average 
(29 percent versus 13 percent). The percentage of minorities living 
within 3 miles of any source affected by this rule is 37 percent above 
the national average (35 percent versus 28 percent). The large minority 
population is a direct result of the higher percentage of African 
Americans living near these facilities (the other racial minorities are 
below or equal to the national average). However, as noted previously, 
we found the risks from these source categories to be acceptable for 
all populations.
    The proposed changes to the standard increase the level of 
environmental protection for all affected populations by ensuring no 
future emission increases from the source categories. Additionally, the 
proposed standards for Hg emissions from phosphate rock calciners will 
reduce Hg emissions, thereby reducing potential exposure to sustenance 
fishers and other sensitive populations. The proximity analysis results 
and the details concerning their development are presented in the 
October 2012 memorandum, ``Environmental Justice Review: Phosphate 
Fertilizer Production and Phosphoric Acid,'' a copy of which is 
available in Docket ID No. EPA-HQ-OAR-2012-0522.

List of Subjects

40 CFR Part 60

    Environmental protection, Air pollution control, Fertilizers, 
Fluoride, Particulate matter, Phosphate, Reporting and recordkeeping 
requirements.

[[Page 66561]]

40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous 
substances, Incorporation by reference, Reporting and recordkeeping 
requirements.

    Dated: October 21, 2014.
Gina McCarthy,
Administrator.
    For the reasons stated in the preamble, the Environmental 
Protection Agency proposes to amend title 40, chapter I, of the Code of 
Federal Regulations as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

0
1. The authority citation for part 60 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

Subpart T--Standards of Performance for the Phosphate Fertilizer 
Industry: Wet-Process Phosphoric Acid Plants

0
2. Section 60.200 is amended by revising paragraph (a) to read as 
follows:


Sec.  60.200  Applicability and designation of affected facility.

    (a) The affected facility to which the provisions of this subpart 
apply is each wet-process phosphoric acid plant having a design 
capacity of more than 15 tons of equivalent P2O5 
feed per calendar day.
* * * * *
0
3. Section 60.201 is amended by revising paragraph (a) to read as 
follows.


Sec.  60.201  Definitions.

* * * * *
    (a) Wet-process phosphoric acid plan means any facility 
manufacturing phosphoric acid by reacting phosphate rock and acid. A 
wet-process phosphoric acid plant includes, but is not limited to: 
reactors, filters, evaporators, hot wells, clarifiers, and 
defluorination systems.
* * * * *
0
4. Section 60.203 is amended by revising paragraph (c) and adding 
paragraph (d) to read as follows:


Sec.  60.203  Monitoring of operations.

* * * * *
    (c) The owner or operator of any wet-process phosphoric acid plant 
subject to the provisions of this part shall install, calibrate, 
maintain, and operate a monitoring device which continuously measures 
and permanently records the total pressure drop across the absorber. 
The monitoring device shall have an accuracy of 5 percent 
over its operating range.
    (d) Any facility under Sec.  60.200(a) that commences construction, 
modification or reconstruction after [date of publication of the final 
rule in the Federal Register] is subject to the requirements of this 
paragraph instead of the requirements in paragraph (c) of this section. 
If an absorber is used to comply with Sec.  60.202, then the owner or 
operator shall continuously monitor pressure drop through the absorber 
and meet the requirements specified in paragraphs (d)(1) through (4) of 
this section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of 5 percent over the 
normal range measured or 0.12 kilopascals (0.5 inches of water column), 
whichever is greater.
    (3) The owner or operator shall establish an allowable range for 
the pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (d)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.
0
5. Subpart T is amended by adding Sec.  60.205 to read as follows:


Sec.  60.205  Recordkeeping.

    Any facility under Sec.  60.200(a) that commences construction, 
modification or reconstruction after [date of publication of the final 
rule in the Federal Register] is subject to the requirements of this 
section. You must maintain the records identified as specified in Sec.  
60.7(f) and in paragraphs (a) and (b) of this section. All records 
required by this subpart must be maintained on site for at least 5 
years.
    (a) Records of the daily average pressure. Records of the daily 
average pressure drop through the absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (2) of this 
section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.203(d)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

Subpart U--Standards of Performance for the Phosphate Fertilizer 
Industry: Superphosphoric Acid Plants

0
6. Section 60.210 is amended by revising paragraph (a) to read as 
follows:


Sec.  60.210  Applicability and designation of affected facility.

    (a) The affected facility to which the provisions of this subpart 
apply is each superphosphoric acid plant having a design capacity of 
more than 15 tons of equivalent P2O5 feed per 
calendar day.
* * * * *
0
7. Section 60.211 is amended by revising paragraph (a) to read as 
follows:


Sec.  60.211  Definitions.

* * * * *
    (a) Superphosphoric acid plant means any facility which 
concentrates wet-process phosphoric acid to 66 percent or greater 
P2O5 content by weight for eventual consumption 
as a fertilizer. A superphosphoric acid plant includes, but is not 
limited to: evaporators, hot wells, acid sumps, oxidation reactors, and 
cooling tanks.
* * * * *
0
8. Section 60.213 is amended by revising paragraph (c) and adding 
paragraph (d) to read as follows:


Sec.  60.213  Monitoring of operations.

* * * * *
    (c) Except as specified in paragraph (d) of this section, the owner 
or operator

[[Page 66562]]

of any superphosphoric acid plant subject to the provisions of this 
part shall install, calibrate, maintain, and operate a monitoring 
device which continuously measures and permanently records the total 
pressure drop across the absorber. The monitoring device shall have an 
accuracy of 5 percent over its operating range.
    (d) Any affected facility as defined in Sec.  60.210(a) that 
commences construction, modification or reconstruction after [date of 
publication of the final rule in the Federal Register] is subject to 
the requirements of this paragraph instead of the requirements in 
paragraph (c) of this section. If an absorber is used to comply with 
Sec.  60.212, then the owner or operator shall continuously monitor 
pressure drop through the absorber and meet the requirements specified 
in paragraphs (d)(1) through (4) of this section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of 5 percent over the 
normal range measured or 0.12 kilopascals (0.5 inches of water column), 
whichever is greater.
    (3) The owner or operator shall establish an allowable range for 
the pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (d)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.
0
9. Subpart U is amended by adding Sec.  60.215 to read as follows:


Sec.  60.215  Recordkeeping.

    An affected facility as defined in Sec.  60.210(a) that commences 
construction, modification, or reconstruction after [date of 
publication of the final rule in the Federal Register] is subject to 
the requirements of this section. You must maintain the records 
identified as specified in Sec.  60.7(f) and in paragraphs (a) and (b) 
of this section. All records required by this subpart must be 
maintained on site for at least 5 years.
    (a) Records of the daily average pressure drop through the 
absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (b)(2) of 
this section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.213(d)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

Subpart V--Standards of Performance for the Phosphate Fertilizer 
Industry: Diammonium Phosphate Plants

0
10. Section 60.223 is amended by revising paragraph (c) and adding 
paragraph (d) to read as follows:


Sec.  60.223  Monitoring of operations.

* * * * *
    (c) Except as specified in paragraph (d) of this section, the owner 
or operator of any granular diammonium phosphate plant subject to the 
provisions of this subpart shall install, calibrate, maintain, and 
operate a monitoring device which continuously measures and permanently 
records the total pressure drop across the scrubbing system. The 
monitoring device shall have an accuracy of 5 percent over 
its operating range.
    (d) Any affected facility as defined in Sec.  60.220(a) that 
commences construction, modification, or reconstruction after [date of 
publication of the final rule in the Federal Register] is subject to 
the requirements of this paragraph instead of the requirements in 
paragraph (c) of this section. If an absorber is used to comply with 
Sec.  60.222, then the owner or operator shall continuously monitor 
pressure drop through the absorber and meet the requirements specified 
in paragraphs (d)(1) through (4) of this section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of  5 percent over 
the normal range measured or 0.12 kilopascals (0.5 inches of water 
column), whichever is greater.
    (3) The owner or operator shall establish an allowable range for 
the pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (d)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.
0
11. Section 60.224 is amended by revising paragraph (b)(3)(ii) to read 
as follows:


Sec.  60.224  Test methods and procedures.

* * * * *
    (b) * * *
    (3) * * *
    (ii) The Association of Official Analytical Chemists (AOAC) Method 
9 (incorporated by reference--see Sec.  60.17)

[[Page 66563]]

shall be used to determine the P2O5 content 
(Rp) of the feed.
0
12. Subpart V is amended by adding Sec.  60.225 to read as follows:


Sec.  60.225  Recordkeeping.

    An affected facility as defined in Sec.  60.220(a) that commences 
construction, modification, or reconstruction after [date of 
publication of the final rule in the Federal Register] is subject to 
the requirements of this section. You must maintain the records 
identified as specified in Sec.  60.7(f) and in paragraphs (a) and (b) 
of this section. All records required by this subpart must be 
maintained on site for at least 5 years.
    (a) Records of the daily average pressure drop through the 
absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (2) of this 
section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.223(d)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

Subpart W--Standards of Performance for the Phosphate Fertilizer 
Industry: Triple Superphosphate Plants

0
13. Section 60.230 is amended by revising paragraph (a) to read as 
follows:


Sec.  60.230  Applicability and designation of affected facility.

    (a) The affected facility to which the provisions of this subpart 
apply is each triple superphosphate plant having a design capacity of 
more than 15 tons of equivalent P2O5 feed per 
calendar day. For the purpose of this subpart, the affected facility 
includes any combination of: mixers, curing belts (dens), reactors, 
granulators, dryers, coolers, screens, mills, and facilities which 
store run-of-pile triple superphosphate.
* * * * *
0
14. Section 60.233 is revised to read as follows:


Sec.  60.233  Monitoring of operations.

    (a) The owner or operator of any triple superphosphate plant 
subject to the provisions of this subpart shall install, calibrate, 
maintain, and operate a flow monitoring device which can be used to 
determine the mass flow of phosphorus-bearing feed material to the 
process. The flow monitoring device shall have an accuracy of 5 percent over its operating range.
    (b) The owner or operator of any triple superphosphate plant shall 
maintain a daily record of equivalent P2O5 feed 
by first determining the total mass rate in Mg/hr of phosphorus-bearing 
feed using a flow monitoring device meeting the requirements of 
paragraph (a) of this section and then by proceeding according to Sec.  
60.234(b)(3).
    (c) Except as specified in paragraph (d) of this section, the owner 
or operator of any triple superphosphate plant subject to the 
provisions of this part shall install, calibrate, maintain, and operate 
a monitoring device which continuously measures and permanently records 
the total pressure drop across the absorber. The monitoring device 
shall have an accuracy of 5 percent over its operating 
range.
    (d) Any facility under Sec.  60.230(a) that commences construction, 
modification, or reconstruction after [date of publication of the final 
rule in the Federal Register] is subject to the requirements of this 
paragraph instead of the requirements in paragraph (c) of this section. 
If an absorber is used to comply with Sec.  60.232, then the owner or 
operator shall continuously monitor pressure drop through the absorber 
and meet the requirements specified in paragraphs (d)(1) through (4) of 
this section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of  5 percent over 
the normal range measured or 0.12 kilopascals (0.5 inches of water 
column), whichever is greater.
    (3) The owner or operator shall establish an allowable range for 
the pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (d)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.
0
15. Subpart W is amended by adding Sec.  60.235 to read as follows:


Sec.  60.235  Recordkeeping.

    Any facility under Sec.  60.230(a) that commences construction, 
modification, or reconstruction after [date of publication of the final 
rule in the Federal Register] is subject to the requirements of this 
section. You must maintain the records identified as specified in Sec.  
60.7(f) and in paragraphs (a) and (b) of this section. All records 
required by this subpart must be maintained onsite for at least 5 
years.
    (a) Records of the daily average pressure drop through the 
absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (2) of this 
section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.233(d)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

Subpart X--Standards of Performance for the Phosphate Fertilizer 
Industry: Granular Triple Superphosphate Storage Facilities

0
16. Section 60.243 is amended by revising paragraph (c) and adding (e) 
to read as follows:


Sec.  60.243  Monitoring of operations.

* * * * *
    (c) Except as specified in paragraph (e) of this section, the owner 
or operator of any granular triple superphosphate storage facility 
subject to the provisions

[[Page 66564]]

of this subpart shall install, calibrate, maintain, and operate a 
monitoring device which continuously measures and permanently records 
the total pressure drop across any absorber. The monitoring device 
shall have an accuracy of 5 percent over its operating 
range.
* * * * *
    (e) Any facility under Sec.  60.240(a) that commences construction, 
modification, or reconstruction after [date of publication of the final 
rule in the Federal Register] is subject to the requirements of this 
paragraph instead of the requirements in paragraph (c) of this section. 
If an absorber is used to comply with Sec.  60.232, then the owner or 
operator shall continuously monitor pressure drop through the absorber 
and meet the requirements specified in paragraphs (e)(1) through (4) of 
this section.
    (1) The owner or operator shall install, calibrate, maintain, and 
operate a continuous monitoring system (CMS) that continuously measures 
and permanently records the pressure at the gas stream inlet and outlet 
of the absorber. The pressure at the gas stream inlet of the absorber 
may be measured using amperage on the blower if a correlation between 
pressure and amperage is established.
    (2) The CMS must have an accuracy of  5 percent over 
the normal range measured or 0.12 kilopascals (0.5 inches of water 
column), whichever is greater.
    (3) The owner or operator shall establish an allowable range for 
the pressure drop through the absorber. The allowable range is 20 percent of the arithmetic average of the three test runs 
conducted during the performance test required in Sec.  60.8. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (4) The owner or operator shall demonstrate continuous compliance 
by maintaining the daily average pressure drop through the absorber to 
within the allowable range established in paragraph (e)(3) of this 
section. The daily average pressure drop through the absorber for each 
operating day shall be calculated using the data recorded by the 
monitoring system. If the emissions unit operation is continuous, the 
operating day is a 24-hour period. If the emissions unit operation is 
not continuous, the operating day is the total number of hours of 
control device operation per 24-hour period. Valid data points must be 
available for 75 percent of the operating hours in an operating day to 
compute the daily average.
0
17. Subpart X is amended by adding Sec.  60.245 to read as follows:


Sec.  60.245  Recordkeeping.

    Any facility under Sec.  60.240(a) that commences construction, 
modification, or reconstruction after [date of publication of the final 
rule in the Federal Register] is subject to the requirements of this 
section. You must maintain the records identified as specified in Sec.  
60.7(f) and in paragraphs (a) and (b) of this section. All records 
required by this subpart must be maintained onsite for at least 5 
years.
    (a) Records of the daily average pressure drop through the 
absorber.
    (b) Records of deviations. A deviation is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (b)(1) and (2) of this 
section being met.
    (1) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum pressure drop, or greater 
than the maximum pressure drop established in Sec.  60.243(e)(3).
    (2) A deviation occurs when the monitoring data are not available 
for at least 75 percent of the operating hours in a day.

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS 
FOR SOURCE CATEGORIES

0
18. The authority citation for part 63 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

Subpart A--General Provisions

0
19. Section 63.14 is amended by revising paragraphs (b), (c)(1) through 
(7), and (l)(2) to read as follows.


Sec.  63.14  Incorporations by reference.

* * * * *
    (b) The Association of Florida Phosphate Chemists, P.O. Box 1645, 
Bartow, Florida 33830.
    (1) Book of Methods Used and Adopted By The Association of Florida 
Phosphate Chemists, Seventh Edition 1991:
    (i) Section IX, Methods of Analysis for Phosphate Rock, No. 1 
Preparation of Sample, IBR approved for Sec.  63.606(f)(3)(ii)(A), 
Sec.  63.626(f)(3)(ii)(A).
    (ii) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus--P2O5 or 
Ca3(PO4)2, Method A--Volumetric 
Method, IBR approved for Sec.  63.606(f)(3)(ii)(B), Sec.  
63.626(f)(3)(ii)(B).
    (iii) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method B--Gravimetric 
Quimociac Method, IBR approved for Sec.  63.606(f)(3)(ii)(C), Sec.  
63.626(f)(3)(ii)(C).
    (iv) Section IX, Methods of Analysis For Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method C--
Spectrophotometric Method, IBR approved for Sec.  63.606(f)(3)(ii)(D), 
Sec.  63.626(f)(3)(ii)(D).
    (v) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method A--Volumetric 
Method, IBR approved for Sec.  63.606(f)(3)(ii)(E), Sec.  
63.626(f)(3)(ii)(E), and Sec.  63.626(g)(6)(i).
    (vi) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method B--Gravimetric 
Quimociac Method, IBR approved for Sec.  63.606(f)(3)(ii)(F), Sec.  
63.626(f)(3)(ii)(F), and Sec.  63.626(g)(6)(ii).
    (vii) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method C--
Spectrophotometric Method, IBR approved for Sec.  63.606(f)(3)(ii)(G), 
Sec.  63.626(f)(3)(ii)(G), and Sec.  63.626(g)(6)(iii).
    (2) [Reserved]
    (c) * * *
    (1) AOAC Official Method 929.01 Sampling of Solid Fertilizers, 
Sixteenth edition, 1995, IBR approved for Sec.  63.626(g)(7)(ii).
    (2) AOAC Official Method 929.02 Preparation of Fertilizer Sample, 
Sixteenth edition, 1995, IBR approved for Sec.  63.626(g)(7)(iii).
    (3) AOAC Official Method 957.02 Phosphorus (Total) in Fertilizers, 
Preparation of Sample Solution, Sixteenth edition, 1995, IBR approved 
for Sec.  63.626(g)(7)(i).
    (4) AOAC Official Method 958.01 Phosphorus (Total) in Fertilizers, 
Spectrophotometric Molybdovanadophosphate Method, Sixteenth edition, 
1995, IBR approved for Sec.  63.626(g)(7)(vii).
    (5) AOAC Official Method 962.02 Phosphorus (Total) in Fertilizers, 
Gravimetric Quinolinium Molybdophosphate Method, Sixteenth edition, 
1995, IBR approved for Sec.  63.626(g)(7)(vi).

[[Page 66565]]

    (6) AOAC Official Method 969.02 Phosphorus (Total) in Fertilizers, 
Alkalimetric Quinolinium Molybdophosphate Method, Sixteenth edition, 
1995, IBR approved for Sec.  63.626(g)(7)(v).
    (7) AOAC Official Method 978.01 Phosphorus (Total) in Fertilizers, 
Automated Method, Sixteenth edition, 1995, IBR approved for Sec.  
63.626(g)(7)(iv).
* * * * *
    (l) * * *
    (2) Office Of Air Quality Planning And Standards (OAQPS), Fabric 
Filter Bag Leak Detection Guidance, EPA-454/R-98-015, September 1997, 
IBR approved for Sec. Sec.  63.548(e)(4), 63.606(m), 63.607(b)(2)(ii), 
63.626(h), 63.627(b)(2)(iii), 63.7525(j)(2), and 63.11224(f)(2).
* * * * *
0
20. Part 63 is amended by revising subpart AA to read as follows:

Subpart AA--National Emission Standards for Hazardous Air 
Pollutants From Phosphoric Acid Manufacturing Plants

Sec.
63.600 Applicability.
63.601 Definitions.
63.602 Standards and compliance dates.
63.603 [Reserved]
63.604 [Reserved]
63.605 Operating and monitoring requirements.
63.606 Performance tests and compliance provisions.
63.607 Notification, recordkeeping, and reporting requirements.
63.608 General requirements and applicability of part 63 general 
provisions.
63.609 [Reserved]
63.610 Exemption from new source performance standards.
63.611 Implementation and enforcement.
Table 1 to Subpart AA of Part 63--Existing Source Phase 1 Emission 
Limits
Table 1a to Subpart AA of Part 63--Existing Source Phase 2 Emission 
Limits and Work Practice Standards
Table 2 to Subpart AA of Part 63--New Source Phase 1 Emission Limits
Table 2a to Subpart AA of Part 63--New Source Phase 2 Emission 
Limits and Work Practices
Table 3 to Subpart AA of Part 63--Monitoring Equipment Operating 
Parameters
Table 4 to Subpart AA of Part 63--Operating Parameters, Operating 
Limits and Data Monitoring, Recordkeeping and Compliance Frequencies
Table 5 to Subpart AA of Part 63--Calibration and Quality Control 
Requirements for Continuous Parameter Monitoring System (CPMS)
Appendix A to Subpart AA of Part 63--Applicability of General 
Provisions (40 CFR Part 63, Subpart A) to Subpart AA


Sec.  63.600  Applicability.

    (a) Except as provided in paragraphs (c) and (d) of this section, 
you are subject to the requirements of this subpart if you own or 
operate a phosphoric acid manufacturing plant that is a major source as 
defined in Sec.  63.2. You must comply with the emission limitations, 
work practice standards, and operating parameter requirements specified 
in this subpart at all times.
    (b) The requirements of this subpart apply to emissions of 
hazardous air pollutants (HAP) emitted from the following affected 
sources at a phosphoric acid manufacturing plant:
    (1) Each wet-process phosphoric acid process line.
    (2) Each evaporative cooling tower.
    (3) Each phosphate rock dryer.
    (4) Each phosphate rock calciner.
    (5) Each superphosphoric acid process line.
    (6) Each purified phosphoric acid process line.
    (7) Each gypsum dewatering stack pond associated with the 
phosphoric acid manufacturing plant.
    (c) The requirements of this subpart do not apply to a phosphoric 
acid manufacturing plant that is an area source as defined in Sec.  
63.2.
    (d) The provisions of this subpart do not apply to research and 
development facilities as defined in Sec.  63.601.


Sec.  63.601  Definitions.

    Terms used in this subpart are defined in Sec.  63.2 of the Clean 
Air Act and in this section as follows:
    Active gypsum dewatering stack means a gypsum dewatering stack that 
does not meet the definition of closed gypsum dewatering stack.
    Breakthrough means the point in time when the level of mercury 
detected at the outlet of an adsorber system is 90 percent of the 
highest concentration allowed to be discharged consistent with the 
applicable emission limit.
    Closed gypsum dewatering stack means a gypsum dewatering stack that 
is no longer receiving phosphogypsum, and has received a cover on the 
top and sides. The final cover of a closed gypsum dewatering stack must 
include a barrier soil layer that will sustain vegetation and a drought 
resistant vegetative cover.
    Cooling pond means a natural or artificial open reservoir that is 
primarily used to collect and cool water that comes into direct contact 
with raw materials, intermediate products, by-products, waste products, 
or finished products from a phosphoric acid manufacturing plant. The 
water in the cooling pond is often used at phosphoric acid 
manufacturing plants as filter wash water, absorber water for air 
pollution control absorbers, and/or to transport phosphogypsum as 
slurry to a gypsum dewatering stack(s).
    Equivalent P 2O5 feed means the quantity of phosphorus, expressed 
as phosphorus pentoxide (P2O5), fed to the 
process.
    Evaporative cooling tower means an open-water, re-circulating 
device that uses fans or natural draft to draw or force ambient air 
through the device to remove heat from process water by direct contact.
    Exceedance means a departure from an indicator range established 
for monitoring under this subpart, consistent with any averaging period 
specified for averaging the results of the monitoring.
    Existing source depends on the date that construction or 
reconstruction of an affected source commenced. A wet-process 
phosphoric acid process line, superphosphoric acid process line, rock 
dryer, rock calciner, evaporative cooling tower, or purified acid 
process line is an existing source if construction or reconstruction of 
the affected source commenced on or before December 27, 1996. A gypsum 
dewatering stack or cooling pond is an existing source if construction 
or reconstruction of the gypsum dewatering stack or cooling pond 
commenced on or before [date of publication of the final rule in the 
Federal Register].
    Gypsum dewatering stack means the phosphogypsum stack (or pile, or 
landfill), together with all pumps, piping, ditches, drainage 
conveyances, water control structures, collection pools, cooling ponds, 
surge ponds, auxiliary holding ponds, and any other collection or 
conveyance system associated with the transport of phosphogypsum from 
the plant to the gypsum dewatering stack, its management at the stack, 
and the process wastewater return to the phosphhoric acid production or 
other process. This definition includes toe drain systems, ditches and 
other leachate collection systems, but does not include conveyances 
within the confines of the fertilizer plant or emergency diversion 
impoundments used in emergency circumstances caused by rainfall events 
of high volume or duration for the temporary storage of process 
wastewater to avoid discharges to surface waters.
    HAP metals mean those metals and their compounds (in particulate or 
volatile form) that are included on the list of hazardous air 
pollutants in section 112 of the Clean Air Act. HAP metals include, but 
are not limited to:

[[Page 66566]]

antimony, arsenic, beryllium, cadmium, chromium, Pb, manganese, nickel, 
and selenium expressed as particulate matter as measured by the methods 
and procedures in this subpart or an approved alternative method. For 
the purposes of this subpart, HAP metals (except mercury) are expressed 
as particulate matter as measured by Method 5 at 40 CFR part 60, 
appendix A-3.
    New source depends on the date that construction or reconstruction 
of an affected source commences. A wet-process phosphoric acid process 
line, superphosphoric acid process line, rock dryer, rock calciner, 
evaporative cooling tower, or purified acid process line is a new 
source if construction or reconstruction of the affected source 
commenced after December 27, 1996. A gypsum dewatering stack or cooling 
pond is a new source if construction or reconstruction of the gypsum 
dewatering stack or cooling pond commenced after [date of publication 
of the final rule in the Federal Register]
    Phosphate rock calciner means the equipment used to remove moisture 
and organic matter from phosphate rock through direct or indirect 
heating.
    Phosphate rock dryer means the equipment used to reduce the 
moisture content of phosphate rock through direct or indirect heating.
    Phosphate rock feed means all material entering any phosphate rock 
dryer or phosphate rock calciner including moisture and extraneous 
material as well as the following ore materials: fluorapatite, 
hydroxylapatite, chlorapatite, and carbonateapatite.
    Phosphoric acid defluorination process means any process that 
treats phosphoric acid in a manner that removes fluorine compounds.
    Phosphoric acid oxidation reactor means any equipment that uses an 
oxidizing agent to treat phosphoric acid.
    Process line means all equipment associated with the production of 
any grade or purity of a phosphoric acid product including emission 
control equipment.
    Purified phosphoric acid process line means any process line that 
uses a HAP as a solvent in the separation of impurities from the 
product acid for the purposes of rendering that product suitable for 
industrial, manufacturing, or food grade uses. A purified phosphoric 
acid process line includes, but is not limited to: solvent extraction 
process equipment, solvent stripping and recovery equipment, seal 
tanks, carbon treatment equipment, cooling towers, storage tanks, 
pumps, and process piping.
    Raffinate stream means the aqueous stream containing the impurities 
that are removed during the purification of wet-process phosphoric acid 
using solvent extraction.
    Research and development facility means research or laboratory 
operations whose primary purpose is to conduct research and development 
into new processes and products, where the operations are under the 
close supervision of technically trained personnel, and where the 
facility is not engaged in the manufacture of products for commercial 
sale in commerce or other off-site distribution, except in a de minimis 
manner.
    Superphosphoric acid process line means any process line that 
concentrates wet-process phosphoric acid to 66 percent or greater 
P2O5 content by weight. A superphosphoric acid 
process line includes, but is not limited to: evaporators, hot wells, 
acid sumps, oxidation reactors, and cooling tanks.
    Total fluorides means elemental fluorine and all F compounds, 
including the HAP HF, as measured by reference methods specified in 40 
CFR part 60, appendix A, Method 13 A or B, or by equivalent or 
alternative methods approved by the Administrator pursuant to Sec.  
63.7(f).
    Wet-process phosphoric acid process line means any process line 
manufacturing phosphoric acid by reacting phosphate rock and acid. A 
wet-process phosphoric acid process line includes, but is not limited 
to: Reactors, filters, evaporators, hot wells, clarifiers, and 
defluorination systems.


Sec.  63.602  Standards and compliance dates.

    (a) On and after the date on which the initial performance test 
specified in Sec. Sec.  63.7 and 63.606 is required to be completed, 
for each wet-process phosphoric acid process line, superphosphoric acid 
process line, rock dryer, and rock calciner, you must comply with the 
emission limits and work practice standards as specified in paragraphs 
(a)(1) through (6) of this section. If a process line contains more 
than one emission point, you must sum the emissions from all emission 
points in a process line to determine compliance with the specified 
emission limits.
    (1) For each existing wet-process phosphoric acid process line, 
superphosphoric acid process line, and rock dryer that commenced 
construction or reconstruction on or before December 27, 1996, you must 
comply with the emission limits specified in Table 1 to this subpart 
beginning on June 10, 2002 and ending on [date one year after the date 
of publication of the final rule in the Federal Register]. Beginning on 
[date one year after the date of publication of the final rule in the 
Federal Register], the emission limits specified in Table 1 to this 
subpart no longer apply, and you must comply with the emission limits 
specified in Table 1a to this subpart.
    (2) For each existing rock calciner that commenced construction or 
reconstruction on or before December 27, 1996, you must comply with the 
emission limits as specified in paragraphs (a)(2)(i) and (ii) of this 
section, and the work practice standards as specified in paragraph 
(a)(2)(iii) of this section.
    (i) You must comply with the total particulate emission limit 
specified in Tables 1 and 1a to this subpart beginning on June 10, 
2002.
    (ii) You must comply with the mercury emission limit specified in 
Table 1a to this subpart beginning on [date three years after the date 
of publication of the final rule in the Federal Register].
    (iii) You must comply with the hydrogen fluoride work practice 
standards specified in Table 1a to this subpart beginning on [date of 
publication of the final rule in the Federal Register].
    (3) For each new wet-process phosphoric acid process line, 
superphosphoric acid process line, and rock dryer that commences 
construction or reconstruction after December 27, 1996 and on or before 
[date of publication of the final rule in the Federal Register], you 
must comply with the emission limits specified in Table 2 to this 
subpart beginning at startup or on June 10, 1999, whichever is later, 
and ending on [date one year after the date of publication of the final 
rule in the Federal Register]. Beginning on [date one year after the 
date of publication of the final rule in the Federal Register], the 
emission limits specified in Table 2 to this subpart no longer apply, 
and you must comply with the emission limits specified in Table 2a to 
this subpart beginning on [date one year after the date of publication 
of the final rule in the Federal Register] or immediately upon startup, 
whichever is later.
    (4) For each new wet-process phosphoric acid process line, 
superphosphoric acid process line, and rock dryer that commences 
construction or reconstruction after [date of publication of the final 
rule in the Federal Register], you must comply with the emission limits 
specified in Table 2a to this subpart immediately upon startup.

[[Page 66567]]

    (5) For each new rock calciner that commences construction or 
reconstruction after December 27, 1996 and on or before [date of 
publication of the final rule in the Federal Register], you must comply 
with the emission limits as specified in paragraphs (a)(5)(i) and (ii) 
of this section, and the work practice standards as specified in 
paragraph (a)(5)(iii) of this section.
    (i) You must comply with the total particulate emission limit 
specified in Tables 2 and 2a to this subpart beginning on June 10, 1999 
or at startup, whichever is later.
    (ii) You must comply with the mercury emission limit specified in 
Table 2a to this subpart beginning on [date one year after the date of 
publication of the final rule in the Federal Register].
    (iii) You must comply with the hydrogen fluoride work practice 
standards specified in Table 2a to this subpart beginning on [date of 
publication of the final rule in the Federal Register].
    (6) For each new rock calciner that commences construction or 
reconstruction after [date of publication of the final rule in the 
Federal Register], you must comply with the emission limits and work 
practices standards specified in Table 2a to this subpart immediately 
upon startup.
    (b) For each existing and new purified phosphoric acid process 
line, you must comply with the provisions of subpart H of this part and 
maintain:
    (1) A 30-day rolling average of daily concentration measurements of 
methyl isobutyl ketone equal to or below 20 parts per million by weight 
(ppmw) for each product acid stream.
    (2) A 30-day rolling average of daily concentration measurements of 
methyl isobutyl ketone equal to or below 30 ppmw for each raffinate 
stream.
    (3) The daily average temperature of the exit gas stream from the 
chiller stack below 50 degrees Fahrenheit.
    (c) You must not introduce into any existing or new evaporative 
cooling tower any liquid effluent from any wet scrubbing device 
installed to control emissions from process equipment.
    (d) For each existing gypsum dewatering stack or cooling pond that 
commenced construction or reconstruction on or before [date of 
publication of the final rule in the Federal Register], you must 
prepare, and operate in accordance with, a gypsum dewatering stack and 
cooling pond management plan that contains the information specified in 
paragraph (f) of this section beginning on [date one year after the 
date of publication of the final rule in the Federal Register].
    (e) For each new gypsum dewatering stack or cooling pond that 
commences construction or reconstruction after [date of publication of 
the final rule in the Federal Register], you must prepare, and operate 
in accordance with, a gypsum dewatering stack and cooling pond 
management plan that contains the information specified in paragraph 
(f) of this section beginning on [date of publication of the final rule 
in the Federal Register].
    (f) The gypsum dewatering stack and cooling pond management plan 
must include the information specified in paragraphs (f)(1) through (3) 
of this section.
    (1) Location and size (i.e., current total footprint acreage) of 
each closed gypsum dewatering stack, active gypsum dewatering stack, 
and cooling pond.
    (2) Control techniques that are used to minimize hydrogen fluoride 
and fugitive dust emissions from exposed surface areas of each active 
gypsum dewatering stack and cooling pond. For each active gypsum 
dewatering stack and cooling pond that commenced construction or 
reconstruction on or before [date of publication of the final rule in 
the Federal Register], you must use, and include in the management 
plan, at least one of the control techniques listed in paragraphs 
(f)(2)(i) through (vi) of this section. For each active gypsum 
dewatering stack and cooling pond that commences construction or 
reconstruction after [date of publication of the final rule in the 
Federal Register], you must use, and include in the management plan, at 
least two of the control techniques listed in paragraphs (f)(2)(i) 
through (vi) of this section.
    (i) Submerge the discharge pipe along with any necessary siphon 
breaks to a level below the surface of the cooling pond or the surface 
of the pond associated with the active gypsum dewatering stack.
    (ii) Minimize the surface area of the active gypsum dewatering 
stack by using a rim ditch (cell) building technique or other building 
technique.
    (iii) Wet the active gypsum dewatering stack during hot or dry 
periods.
    (iv) Apply slaked lime to the active gypsum dewatering stack 
surfaces.
    (v) Apply soil caps and vegetation to all side slopes of the active 
gypsum dewatering stack up to 50 feet below the stack top.
    (vi) Close the active gypsum dewatering stack such that it meets 
the definition of a closed gypsum dewatering stack specified in Sec.  
63.601.
    (3) You must conduct calculations and maintain a record of the 
calculations to demonstrate compliance with the ratio requirement 
specified in paragraph (g) of this section.
    (g) After [date of publication of the final rule in the Federal 
Register], whenever a facility commences construction of a new gypsum 
dewatering stack, the ratio of total active gypsum dewatering stack 
area (i.e., sum of the footprint acreage of all active gypsum 
dewatering stacks combined) to annual phosphoric acid manufacturing 
capacity must not be greater than 80 acres per 100,000 tons of annual 
phosphoric acid manufacturing capacity (equivalent 
P2O5 feed).
    (h) To demonstrate compliance with any emission limits specified in 
paragraph (a) of this section during periods of startup and shutdown, 
you must begin operation of any control device(s) being used at the 
affected source prior to introducing any feed into the affected source. 
You must continue operation of the control device(s) through the 
shutdown period until all feed material has been processed through the 
affected source.


Sec.  63.603  [Reserved]


Sec.  63.604  [Reserved]


Sec.  63.605  Operating and monitoring requirements.

    (a) For each wet-process phosphoric acid process line or 
superphosphoric acid process line subject to the provisions of this 
subpart, you must comply with the monitoring requirements specified in 
paragraphs (a)(1) and (2) of this section.
    (1) Install, calibrate, maintain, and operate a continuous 
monitoring system (CMS) according to your site-specific monitoring plan 
specified in Sec.  63.608(c). The CMS must have an accuracy of 5 percent over its operating range and must determine and 
permanently record the mass flow of phosphorus-bearing material fed to 
the process.
    (2) Maintain a daily record of equivalent 
P2O5 feed. Calculate the equivalent 
P2O5 feed by determining the total mass rate, in 
metric ton/hour of phosphorus bearing feed, using the monitoring system 
specified in paragraph (a)(1) of this section and the procedures 
specified in Sec.  63.606(f)(3).
    (b) For each phosphate rock dryer or phosphate rock calciner 
subject to the provisions of this subpart, you must comply with the 
monitoring requirements specified in paragraphs (b)(1) through (3) of 
this section.
    (1) Install, calibrate, maintain, and operate a CMS according to 
your site-specific monitoring plan specified in

[[Page 66568]]

Sec.  63.608(c). The CMS must have an accuracy of 5 percent 
over its operating range and must determine and permanently record 
either:
    (i) The mass flow of phosphorus-bearing feed material to the 
phosphate rock dryer or calciner, or
    (ii) The mass flow of product from the phosphate rock dryer or 
calciner.
    (2) Maintain the records specified in paragraphs (b)(2)(i) and (ii) 
of this section.
    (i) If you monitor the mass flow of phosphorus-bearing feed 
material to the phosphate rock dryer or calciner as specified in 
paragraph (b)(1)(i) of this section, maintain a daily record of 
phosphate rock feed by determining the total mass rate in metric tons/
hour of phosphorus-bearing feed.
    (ii) If you monitor the mass flow of product from the phosphate 
rock dryer or calciner as specified in paragraph (b)(1)(ii) of this 
section, maintain a daily record of product by determining the total 
mass rate in metric ton/hour of product.
    (3) For each phosphate rock calciner, you must comply with the 
requirements in paragraphs (b)(3)(i) and (ii) of this section.
    (i) The CMS must continuously measure and permanently record the 
calcination temperature of the phosphate rock calciner every 15 
minutes.
    (ii) You must comply with the applicable calibration and quality 
control requirements for temperature specified in Table 5 to this 
subpart.
    (c) For each purified phosphoric acid process line, you must comply 
with the monitoring requirements specified in paragraphs (c)(1) and (2) 
of this section.
    (1) Install, calibrate, maintain, and operate a CMS according to 
your site-specific monitoring plan specified in Sec.  63.608(c). The 
CMS must continuously measure and permanently record the stack gas exit 
temperature for each chiller stack.
    (2) Measure and record the concentration of methyl isobutyl ketone 
in each product acid stream and each raffinate stream once each day.
    (d) If you use a control device(s) to comply with the emission 
limits specified in Table 1 or 2 of this subpart, or to comply with the 
emission limits or work practice standards specified in Table 1a or 2a 
of this subpart, you must install a continuous parameter monitoring 
system (CPMS) and comply with the requirements specified in paragraphs 
(d)(1) through (5) of this section.
    (1) You must monitor the operating parameter(s) applicable to the 
control device that you use as specified in Table 3 to this subpart and 
establish the applicable limit or range for the operating parameter 
limit as specified in paragraphs (d)(1)(i) through (iii) of this 
section, as applicable.
    (i) Except as specified in paragraphs (d)(1)(ii) and (iii) of this 
section, determine the value(s) as the arithmetic average of operating 
parameter measurements recorded during with the three test runs 
conducted for the most recent performance test.
    (ii) For any absorber required by the work practice standards for 
phosphate rock calciners in Table 1a or 2a of this subpart, you must 
determine the value(s) based on an engineering assessment. The 
engineering assessment may include, but is not limited to, 
manufacturer's specifications and recommendations and/or a design 
analysis based on accepted chemical engineering principles, measurable 
process parameters, or physical or chemical laws or properties. 
Examples of analytical methods include, but are not limited to, the use 
of material balances based on process stoichiometry and estimation of 
maximum flow rate based on physical equipment design such as pump or 
blower capacities.
    (iii) If you use an absorber or a wet electrostatic precipitator to 
comply with the emission limits in Table 1, 1a, 2, or 2a to this 
subpart and you monitor pressure drop across each absorber or secondary 
voltage for a wet electrostatic precipitator, you must establish 
allowable ranges using the methodology specified in paragraphs 
(d)(1)(iii)(A) and (B) of this section.
    (A) The allowable range for the daily averages of the pressure drop 
across an absorber, or secondary voltage for a wet electrostatic 
precipitator, is 20 percent of the baseline average value 
determined in paragraph (d)(1)(i) of this section. The Administrator 
retains the right to reduce the 20 percent adjustment to 
the baseline average values of operating ranges in those instances 
where performance test results indicate that a source's level of 
emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (B) As an alternative to paragraph (d)(1)(iii)(A) of this section, 
you may establish, and provide to the Administrator for approval, 
allowable ranges for the daily averages of the pressure drop across an 
absorber, or secondary voltage for an electrostatic precipitator, for 
the purpose of assuring compliance with this subpart. You must 
establish the allowable ranges based on the baseline average values 
recorded during previous performance tests, or the results of 
performance tests conducted specifically for the purposes of this 
paragraph. You must conduct all performance tests using the methods 
specified in Sec.  63.606. You must certify that the control devices 
and processes have not been modified since the date of the performance 
test from which you obtained the data used to establish the allowable 
ranges. You must request and obtain approval of the Administrator for 
changes to the allowable ranges. When a source using the methodology of 
this paragraph is retested, you must determine new allowable ranges of 
baseline average values unless the retest indicates no change in the 
operating parameters outside the previously established ranges.
    (2) You must monitor, record, and demonstrate continuous compliance 
using the minimum frequencies specified in Table 4 to this subpart.
    (3) You must comply with the calibration and quality control 
requirements that are applicable to the operating parameter(s) you 
monitor as specified in Table 5 to this subpart.
    (4) If you use a non-regenerative adsorption system to achieve the 
mercury emission limits specified in Table 1a or 2a to this subpart, 
you must comply with the requirements specified in paragraph (e) of 
this section.
    (5) If you use a sorbent injection system to achieve the mercury 
emission limits specified in Table 1a or 2a to this subpart and you use 
a fabric filter to collect the associated particulate matter, the 
system must meet the requirements for fabric filters specified in 
paragraph (f) of this section.
    (e) If you use a non-regenerative adsorption system to achieve the 
mercury emission limits specified in Table 1a or 2a to this subpart, 
you must comply with the requirements specified in paragraphs (e)(1) 
through (3) of this section.
    (1) Determine the adsorber bed life (i.e., the expected life of the 
sorbent in the adsorption system) using the procedures specified in 
paragraphs (e)(1)(i) through (iv) of this section.
    (i) If the adsorber bed is expected (designed) to have a life of 
less than 2 years, determine the outlet concentration of mercury on a 
quarterly basis until breakthrough occurs for the first three adsorber 
bed change-outs. The adsorber bed life shall equal the average length 
of time between each of the three change-outs.
    (ii) If the adsorber bed is expected (designed) to have a life of 2 
years or greater, determine the outlet concentration of mercury on a 
semi-annual basis until breakthrough occurs

[[Page 66569]]

for the first two adsorber bed change-outs. The adsorber bed life must 
equal the average length of time between each of the two change-outs.
    (iii) If more than one adsorber is operated in parallel, or there 
are several identical operating lines controlled by adsorbers, you may 
determine the adsorber bed life by measuring the outlet concentration 
of mercury from one of the adsorbers or adsorber systems rather than 
determining the bed life for each adsorber.
    (iv) The adsorber or adsorber system you select for the adsorber 
bed life test must have the highest expected inlet gas mercury 
concentration and the highest operating rate of any adsorber in 
operation at the affected source. During the test to determine adsorber 
bed life, you must use the fuel that contains the highest level of 
mercury in any fuel-burning unit associated with the adsorption system 
being tested.
    (2) You must replace the sorbent in each adsorber on or before the 
end of the adsorbent bed life, calculated in paragraph (e)(1) of this 
section.
    (3) You must re-establish the adsorber bed life if the sorbent is 
replaced with a different brand or type, or if any process changes are 
made that would lead to a shorter bed lifetime.
    (f) If you use a fabric filter system to comply with the emission 
limits specified in Table 1, 1a, 2, or 2a to this subpart, the fabric 
filter must be equipped with a bag leak detection system that is 
installed, calibrated, maintained, and continuously operated according 
to the requirements in paragraphs (f)(1) through (10) of this section.
    (1) Install a bag leak detection sensor(s) in a position(s) that 
will be representative of the relative or absolute particulate matter 
loadings for each exhaust stack, roof vent, or compartment (e.g., for a 
positive-pressure fabric filter) of the fabric filter.
    (2) Use a bag leak detection system certified by the manufacturer 
to be capable of detecting particulate matter emissions at 
concentrations of 1 milligram per actual cubic meter (0.00044 grains 
per actual cubic feet) or less.
    (3) Use a bag leak detection system equipped with a device to 
continuously record the output signal from the system sensor.
    (4) Use a bag leak detection system equipped with a system that 
will trigger an alarm when an increase in relative particulate matter 
emissions over a preset level is detected. The alarm must be located 
such that the alert is observed readily by plant operating personnel.
    (5) Install a bag leak detection system in each compartment or cell 
for positive-pressure fabric filter systems that do not duct all 
compartments or cells to a common stack. Install a bag leak detector 
downstream of the fabric filter if a negative-pressure or induced-air 
filter system is used. If multiple bag leak detectors are required, the 
system's instrumentation and alarm may be shared among detectors.
    (6) Calibration of the bag leak detection system must, at a 
minimum, consist of establishing the baseline output level by adjusting 
the range and the averaging period of the device and establishing the 
alarm set points and the alarm delay time.
    (7) After initial adjustment, you must not adjust the sensitivity 
or range, averaging period, alarm set points, or alarm delay time 
except as established in your site-specific monitoring plan required in 
Sec.  63.608(c). In no event may the sensitivity be increased more than 
100 percent or decreased by more than 50 percent over a 365-day period 
unless such adjustment follows a complete inspection of the fabric 
filter system that demonstrates that the system is in good operating 
condition.
    (8) Operate and maintain each fabric filter and bag leak detection 
system such that the alarm does not sound more than 5 percent of the 
operating time during a 6-month period. If the alarm sounds more than 5 
percent of the operating time during a 6-month period, it is considered 
an operating parameter exceedance. Calculate the alarm time (i.e., time 
that the alarm sounds) as specified in paragraphs (f)(8)(i) through 
(iii) of this section.
    (i) If inspection of the fabric filter demonstrates that corrective 
action is not required, the alarm duration is not counted in the alarm 
time calculation.
    (ii) If corrective action is required, each alarm time is counted 
as a minimum of 1 hour.
    (iii) If it takes longer than 1 hour to initiate corrective action, 
each alarm time is counted as the actual amount of time taken to 
initiate corrective action.
    (9) If the alarm on a bag leak detection system is triggered, you 
must initiate procedures within 1 hour of an alarm to identify the 
cause of the alarm and then initiate corrective action, as specified in 
Sec.  63.608(d)(2), no later than 48 hours after an alarm. Failure to 
take these actions within the prescribed time periods is considered a 
violation.
    (10) Retain records of any bag leak detection system alarm, 
including the date, time, duration, and the percent of the total 
operating time during each 6-month period that the alarm sounds, with a 
brief explanation of the cause of the alarm, the corrective action 
taken, and the schedule and duration of the corrective action.
    (g) If you choose to directly monitor mercury emissions instead of 
using CPMS as specified in paragraph (d) of this section, then you must 
install and operate a mercury CEMS in accordance with Performance 
Specification 12A of appendix B to part 60 of this chapter, or a 
sorbent trap-based integrated monitoring system in accordance with 
Performance Specification 12B of appendix B to part 60 of this chapter. 
You must continuously monitor mercury emissions as specified in 
paragraphs (g)(1) through (4) of this section.
    (1) The span value for any mercury CEMS must include the intended 
upper limit of the mercury concentration measurement range during 
normal operation, which may be exceeded during other short-term 
conditions lasting less than 24 consecutive operating hours. However, 
the span should be at least equivalent to approximately two times the 
emissions standard. You may round the span value to the nearest 
multiple of 10 micrograms per cubic meter of total mercury.
    (2) You must operate and maintain each mercury CEMS or sorbent 
trap-based integrated monitoring system according to the quality 
assurance requirements specified in Procedure 5 of appendix F to part 
60 of this chapter.
    (3) You must conduct relative accuracy testing of mercury 
monitoring systems, as specified in Performance Specification 12A, 
Performance Specification 12B, or Procedure 5 of appendix B to part 60 
of this chapter, at normal operating conditions.
    (4) If you use a mercury CEMS, you must install, operate, 
calibrate, and maintain an instrument for continuously measuring and 
recording the exhaust gas flow rate to the atmosphere according to your 
site-specific monitoring plan specified in Sec.  63.608(c).


Sec.  63.606  Performance tests and compliance provisions.

    (a) You must conduct an initial performance test to demonstrate 
compliance with the applicable emission limits specified in Tables 1, 
1a, 2, and 2a to this subpart, on or before the applicable compliance 
date specified in Sec.  63.602.
    (b) After you conduct the initial performance test specified in 
paragraph (a) of this section, you must conduct an annual performance 
test no more than 13 months after the date the previous performance 
test was conducted.

[[Page 66570]]

    (c) For affected sources (as defined in Sec.  63.600) that have not 
operated since the previous annual performance test was conducted and 
more than 1 year has passed since the previous performance test, you 
must conduct a performance test no later than 180 days after the re-
start of the affected source according to the applicable provisions in 
Sec.  63.7(a)(2).
    (d) You must conduct the performance tests specified in this 
section at maximum representative operating conditions for the process. 
Maximum representative operating conditions means process operating 
conditions that are likely to recur and that result in the flue gas 
characteristics that are the most difficult for reducing emissions of 
the regulated pollutant(s) by the control device used. The most 
difficult condition for the control device may include, but is not 
limited to, the highest HAP mass loading rate to the control device or 
the highest HAP mass loading rate of constituents that approach the 
limits of solubility for scrubbing media. Operations during startup, 
shutdown, and malfunction do not constitute representative operating 
conditions for purposes of conducting a performance test. You must 
record the process information that is necessary to document the 
operating conditions during the test and include in such record an 
explanation to support that such conditions represent maximum 
representative operating conditions. Upon request, you must make 
available to the Administrator such records as may be necessary to 
determine the conditions of performance tests.
    (e) In conducting all performance tests, you must use as reference 
methods and procedures the test methods in 40 CFR part 60, appendix A, 
or other methods and procedures as specified in this section, except as 
provided in Sec.  63.7(f).
    (f) You must determine compliance with the applicable total 
fluorides standards or hydrogen fluoride standards specified in Tables 
1, 1a, 2, and 2a to this subpart as specified in paragraphs (f)(1) 
through (3) of this section.
    (1) Compute the emission rate (E) of total fluorides or hydrogen 
fluoride for each run using Equation AA-1:
[GRAPHIC] [TIFF OMITTED] TP07NO14.000

Where:

E = Emission rate of total fluorides or hydrogen fluoride, gram/
metric ton (pound/ton) of equivalent P2O5 
feed.
Ci = Concentration of total fluorides or hydrogen 
fluoride from emission point ``i,'' milligram/dry standard cubic 
meter (milligram/dry standard cubic feet).
Qi = Volumetric flow rate of effluent gas from emission 
point ``i,'' dry standard cubic meter/hour (dry standard cubic feet/
hour).
N = Number of emission points associated with the affected facility.
P = Equivalent P2O5 feed rate, metric ton/hour 
(ton/hour).
K = Conversion factor, 1000 milligram/gram (453,600 milligram/
pound).

    (2) You must use the test methods and procedures as specified in 
paragraphs (f)(2)(i) or (ii) of this section.
    (i) You must use Method 13A or 13B (40 CFR part 60, appendix A) to 
determine the total fluorides concentration (Ci) and the 
volumetric flow rate (Qi) of the effluent gas at each 
emission point. The sampling time for each run at each emission point 
must be at least 60 minutes. The sampling volume for each run at each 
emission point must be at least 0.85 dscm (30 dscf). If Method 13B is 
used, the fusion of the filtered material described in Section 7.3.1.2 
and the distillation of suitable aliquots of containers 1 and 2, 
described in section 7.3.3 and 7.3.4 in Method 13 A, may be omitted.
    (ii) You must use Method 320 at 40 CFR part 63, appendix A to 
determine the hydrogen fluoride concentration (Ci) at each 
emission point. The sampling time for each run at each emission point 
must be at least 60 minutes. You must use Method 2 at 40 CFR part 60, 
Appendix A-1 to determine the volumetric flow rate (Qi) of 
the effluent gas from each of the emission points.
    (3) Compute the equivalent P2O5 feed rate (P) 
using Equation AA-2:
[GRAPHIC] [TIFF OMITTED] TP07NO14.001

Where:

P = P2O5 feed rate, metric ton/hr (ton/hour).
Mp = Total mass flow rate of phosphorus-bearing feed, 
metric ton/hour (ton/hour).
Rp = P2O5 content, decimal 
fraction.

    (i) Determine the mass flow rate (Mp) of the phosphorus-
bearing feed using the measurement system described in Sec.  63.605(a).
    (ii) Determine the P2O5 content 
(Rp) of the feed using, as appropriate, the following 
methods specified in Methods Used and Adopted By The Association of 
Florida Phosphate Chemists (Seventh Edition, 1991) where applicable:
    (A) Section IX, Methods of Analysis for Phosphate Rock, No. 1 
Preparation of Sample (incorporated by reference, see Sec.  63.14).
    (B) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method A-Volumetric Method 
(incorporated by reference, see Sec.  63.14).
    (C) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method B-Gravimetric 
Quimociac Method (incorporated by reference, see Sec.  63.14).
    (D) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method C-Spectrophotometric 
Method (incorporated by reference, see Sec.  63.14).
    (E) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method A-Volumetric Method 
(incorporated by reference, see Sec.  63.14).
    (F) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method B-Gravimetric 
Quimociac Method (incorporated by reference, see Sec.  63.14).
    (G) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method C-
Spectrophotometric Method (incorporated by reference, see Sec.  63.14).
    (g) You must demonstrate compliance with the applicable particulate 
matter standards specified in Tables 1, 1a, 2, and 2a to this subpart 
as specified in paragraphs (g)(1) through (3) of this section.
    (1) Compute the emission rate (E) of particulate matter for each 
run using Equation AA-3:
[GRAPHIC] [TIFF OMITTED] TP07NO14.002

Where:
E = Emission rate of particulate matter, kilogram/megagram (pound/
ton) of phosphate rock feed.
C = Concentration of particulate matter, gram/dry standard cubic 
meter (gram/dry standard cubic feet).

[[Page 66571]]

Q = Volumetric flow rate of effluent gas, dry standard cubic meter/
hour (dry standard cubic feet/hour).
P = Phosphate rock feed rate, megagram/hour (ton/hour).
K = Conversion factor, 1000 grams/kilogram (453.6 grams/pound).

    (2) Use Method 5 at 40 CFR part 60, appendix A-3 to determine the 
particulate matter concentration (C) and volumetric flow rate (Q) of 
the effluent gas. Except as specified in paragraph (h) of this section, 
the sampling time and sample volume for each run must be at least 60 
minutes and 0.85 dry standard cubic meter (30 dry standard cubic feet).
    (3) Use the CMS described in Sec.  63.605(b) to determine the 
phosphate rock feed rate (P) for each run.
    (h) To demonstrate compliance with the particulate matter standards 
for phosphate rock calciners specified in Tables 1, 1a, 2, or 2a to 
this subpart, you must use Method 5 at 40 CFR part 60, appendix A-3 to 
determine the particulate matter concentration. The sampling volume for 
each test run must be at least 1.70 dry standard cubic meter.
    (i) To demonstrate compliance with the mercury emission standards 
for phosphate rock calciners specified in Table 1a or 2a to this 
subpart, you must use Method 30B at 40 CFR part 60, appendix A-8 to 
determine the mercury concentration, unless you use a CEMS to 
demonstrate compliance. If you use a non-regenerative adsorber to 
control mercury emissions, you must use this test method to determine 
the expected bed life as specified in Sec.  63.605(e)(1).
    (j) If you choose to monitor the mass flow of product from the 
phosphate rock dryer or calciner as specified in Sec.  
63.605(b)(1)(ii), you must either:
    (1) Simultaneously monitor the feed rate and output rate of the 
phosphate rock dryer or calciner during the performance test, or
    (2) Monitor the output rate and the input and output moisture 
contents of the phosphate rock dryer or calciner during the performance 
test and calculate the corresponding phosphate rock dryer or calciner 
input rate.
    (k) For sorbent injection systems, you must conduct the performance 
test at the outlet of the fabric filter used for sorbent collection. 
You must monitor and record operating parameter values for the fabric 
filter during the performance test. If the sorbent is replaced with a 
different brand or type of sorbent than was used during the performance 
test, you must conduct a new performance test.
    (l) If you use a mercury CEMS as specified in Sec.  63.605(g), or 
paragraph (i) of this section, you must demonstrate initial compliance 
based on the first 30 operating days during which you operate the 
affected source using a CEMS. You must obtain hourly mercury 
concentration and stack gas volumetric flow rate data.
    (m) If you use a CMS, you must conduct a performance evaluation, as 
specified in Sec.  63.8(e), in accordance with your site-specific 
monitoring plan in Sec.  63.608(c). For fabric filters, you must 
conduct a performance evaluation of the bag leak detection system 
consistent with the guidance provided in Office Of Air Quality Planning 
And Standards (OAQPS), Fabric Filter Bag Leak Detection Guidance, EPA-
454/R-98-015, September 1997 (incorporated by reference, see Sec.  
63.14). You must record the sensitivity of the bag leak detection 
system to detecting changes in particulate matter emissions, range, 
averaging period, and alarm set points during the performance test.


Sec.  63.607  Notification, recordkeeping, and reporting requirements.

    (a) You must comply with the notification requirements specified in 
Sec.  63.9. You must also notify the Administrator each time that the 
operating limits change based on data collected during the most recent 
performance test. When a source is retested and the performance test 
results are submitted to the Administrator pursuant to paragraph (b)(1) 
of this section, Sec.  63.7(g)(1), or Sec.  63.10(d)(2), you must 
indicate whether the operating range is based on the new performance 
test or the previously established range. Upon establishment of a new 
operating range, you must thereafter operate under the new range. If 
the Administrator determines that you did not conduct the compliance 
test in accordance with the applicable requirements or that the ranges 
established during the performance test do not represent normal 
operations, you must conduct a new performance test and establish new 
operating ranges.
    (b) You must comply with the reporting and recordkeeping 
requirements in Sec.  63.10 as specified in paragraphs (b)(1) through 
(b)(5) of this section.
    (1) You must comply with the general recordkeeping requirements in 
Sec.  63.10(b)(1).
    (2) As required by Sec.  63.10(d), you must report the results of 
the initial and subsequent performance tests as part of the 
notification of compliance status required in Sec.  63.9(h). You must 
verify in the performance test reports that the operating limits for 
each process have not changed or provide documentation of revised 
operating limits established according to Sec.  63.605, as applicable. 
In the notification of compliance status, you must also:
    (i) Certify to the Administrator annually that you have complied 
with the evaporative cooling tower requirements specified in Sec.  
63.602(c).
    (ii) Submit analyses and supporting documentation demonstrating 
conformance with the Office Of Air Quality Planning And Standards 
(OAQPS), Fabric Filter Bag Leak Detection Guidance, EPA-454/R-98-015, 
September 1997 (incorporated by reference, see Sec.  63.14) and 
specifications for bag leak detection systems as part of the 
notification of compliance status report.
    (iii) Submit the gypsum dewatering stack and cooling pond 
management plan specified in Sec.  63.602(f).
    (iv) If you elect to demonstrate compliance by following the 
procedures in Sec.  63.605(d)(1)(iii)(B), certify to the Administrator 
annually that the control devices and processes have not been modified 
since the date of the performance test from which you obtained the data 
used to establish the allowable ranges.
    (v) Each time a gypsum dewatering stack is closed, certify to the 
Administrator within 90 days of closure, that the final cover of the 
closed gypsum dewatering stack is a drought resistant vegetative cover 
that includes a barrier soil layer that will sustain vegetation.
    (vi) If you operate a phosphate rock calciner, include the 
engineering assessment as required by Sec.  63.605(d)(1)(ii) and the 
information in paragraphs (b)(2)(vi)(A) through (D) of this section.
    (A) Description of the monitoring devices and monitoring 
frequencies.
    (B) The established operating limits of the monitored parameter(s).
    (C) The rationale for the established operating limit, inlcuding 
any data and calculations used to develop the operating limit and a 
description of why the operating limit inidcates proper operation of 
the control device.
    (D) The rationale used to determine which format to use for your 
operating limit (e.g., operating range, minimum operating level or 
maximum operating level), where this subpart does not specify which 
format to use.
    (3) As required by Sec.  63.10(e)(3), you must submit an excess 
emissions report for any exceedance of an emission limit, work practice 
standard, or operating parameter limit if the total duration of the 
exceedances for the reporting period is 1 percent of the total 
operating time for the reporting period or greater. The report must 
contain the information specified in Sec.  63.10 and paragraph (b)(4)

[[Page 66572]]

of this section. When exceedances of an emission limit or operating 
parameter have not occurred, you must include such information in the 
report. You must submit the report semiannually and the report must be 
delivered or postmarked by the 30th day following the end of the 
calendar half. If you report exceedances, you must submit the excess 
emissions report quarterly until a request to reduce reporting 
frequency is approved as described in Sec.  63.10(e)(3)(ii).
    (4) In the event that an affected unit fails to meet an applicable 
standard, record and report the following information for each failure:
    (i) The date, time and duration of the failure.
    (ii) A list of the affected sources or equipment for which a 
failure occurred.
    (iii) An estimate of the volume of each regulated pollutant emitted 
over any emission limit.
    (iv) A description of the method used to estimate the emissions.
    (v) A record of actions taken to minimize emissions in accordance 
with Sec.  63.608(b), and any corrective actions taken to return the 
affected unit to its normal or usual manner of operation.
    (5) You must submit a summary report containing the information 
specified in Sec.  63.10(e)(3)(vi). You must submit the summary report 
semiannually and the report must be delivered or postmarked by the 30th 
day following the end of the calendar half.
    (c) Your records must be in a form suitable and readily available 
for expeditious review. You must keep each record for 5 years following 
the date of each recorded action. You must keep each record on site, or 
accessible from a central location by computer or other means that 
instantly provides access at the site, for at least 2 years after the 
date of each recorded action. You may keep the records off site for the 
remaining 3 years.
    (d) In computing averages to determine compliance with this 
subpart, you must exclude the monitoring data specified in paragraphs 
(d)(1) through (2) of this section.
    (1) Periods of non-operation of the process unit;
    (2) Periods of no flow to a control device; and any monitoring data 
recorded during CEMS or continuous parameter monitoring system (CPMS) 
breakdowns, out-of-control periods, repairs, maintenance periods, 
instrument adjustments or checks to maintain precision and accuracy, 
calibration checks, and zero (low-level), mid-level (if applicable), 
and high-level adjustments.
    (e) Within 60 days after the date of completing each performance 
test (as defined in Sec.  63.2), you must submit the results of the 
performance tests, including any associated fuel analyses, required by 
this subpart according to the methods specified in paragraphs (e)(1) or 
(2) of this section.
    (1) For data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT Web site 
(https://www.epa.gov/ttn/chief/ert/), you must submit the 
results of the performance test to the Compliance and Emissions Data 
Reporting Interface (CEDRI) that is accessed through the EPA's Central 
Data Exchange (CDX) (https://cdx.epa.gov/epa_home.asp), unless the 
Administrator approves another approach. Performance test data must be 
submitted in a file format generated through the use of the EPA's ERT. 
Owners or operators, who claim that some of the information being 
submitted for performance tests is confidential business information 
(CBI), must submit a complete file generated through the use of the 
EPA's ERT, including information claimed to be CBI, on a compact disk, 
flash drive, or other commonly used electronic storage media to the 
EPA. The electronic media must be clearly marked as CBI and mailed to 
U.S. EPA/OAQPS/CORE CBI Office, Attention: WebFIRE Administrator, MD 
C404-02, 4930 Old Page Rd., Durham, NC 27703. The same ERT file with 
the CBI omitted must be submitted to the EPA via CDX as described 
earlier in this paragraph.
    (2) For any performance test conducted using test methods that are 
not supported by the EPA's ERT as listed on the EPA's ERT Web site, the 
owner or operator shall submit the results of the performance test to 
the Administrator at the appropriate address listed in Sec.  63.13.
    (f) Within 60 days after the date of completing each CEMS 
performance evaluation (as defined in Sec.  63.2), you must submit the 
results of the performance evaluation according to the method specified 
by either paragraph (f)(1) or (f)(2) of this section.
    (1) For data collection of relative accuracy test audit (RATA) 
pollutants that are supported by the EPA's ERT as listed on the EPA's 
ERT Web site, you must submit the results of the performance evaluation 
to the CEDRI that is accessed through the EPA's CDX, unless the 
Administrator approves another approach. Performance evaluation data 
must be submitted in a file format generated through the use of the 
EPA's ERT. If you claim that some of the performance evaluation 
information being transmitted is CBI, you must submit a complete file 
generated through the use of the EPA's ERT, including information 
claimed to be CBI, on a compact disk or other commonly used electronic 
storage media (including, but not limited to, flash drives) by 
registered letter to the EPA. The compact disk shall be clearly marked 
as CBI and mailed to U.S. EPA/OAQPS/CORE CBI Office, Attention: WebFIRE 
Administrator, MD C404-02, 4930 Old Page Rd., Durham, NC 27703. The 
same ERT file with the CBI omitted must be submitted to the EPA via CDX 
as described earlier in this paragraph.
    (2) For any performance evaluations with RATA pollutants that are 
not supported by the EPA's ERT as listed on the EPA's ERT Web site, you 
shall submit the results of the performance evaluation to the 
Administrator at the appropriate address listed in Sec.  63.13.


Sec.  63.608  General requirements and applicability of part 63 general 
provisions.

    (a) You must comply with the general provisions in subpart A of 
this part as specified in appendix A to this subpart.
    (b) At all times, you must operate and maintain any affected 
source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions. The general duty 
to minimize emissions does not require you to make any further efforts 
to reduce emissions if levels required by this standard have been 
achieved. Determination by the Administrator of whether a source is 
operating in compliance with operation and maintenance requirements 
will be based on information available to the Administrator that may 
include, but is not limited to, monitoring results, review of operation 
and maintenance procedures, review of operation and maintenance 
records, and inspection of the source.
    (c) For each CMS (including CEMS or CPMS) used to demonstrate 
compliance with any applicable emission limit or work practice, you 
must develop, and submit to the Administrator for approval upon 
request, a site-specific monitoring plan according to the requirements 
specified in paragraphs (c)(1) through (3) of this section. You must 
submit the site-specific monitoring plan, if requested by the 
Administrator, at least 60 days before the initial performance 
evaluation of the CMS. The requirements of this paragraph also apply if 
a petition is made to the Administrator for alternative monitoring 
parameters under Sec.  63.8(f).

[[Page 66573]]

    (1) You must include the information specified in paragraphs 
(c)(1)(i) through (vi) of this section in the site-specific monitoring 
plan.
    (i) Location of the CMS sampling probe or other interface. You must 
include a justification demonstrating that the sampling probe or other 
interface is at a measurement location relative to each affected 
process unit such that the measurement is representative of control of 
the exhaust emissions (e.g., on or downstream of the last control 
device).
    (ii) Performance and equipment specifications for the sample 
interface, the pollutant concentration or parametric signal analyzer, 
and the data collection and reduction systems.
    (iii) Performance evaluation procedures and acceptance criteria 
(e.g., calibrations).
    (iv) Ongoing operation and maintenance procedures in accordance 
with the general requirements of Sec.  63.8(c)(1)(ii), (c)(3), 
(c)(4)(ii), and Table 4 to this subpart.
    (v) Ongoing data quality assurance procedures in accordance with 
the general requirements of Sec.  63.8(d)(1) and (2) and Table 5 to 
this subpart.
    (vi) Ongoing recordkeeping and reporting procedures in accordance 
with the general requirements of Sec.  63.10(c), (e)(1), and (e)(2)(i).
    (2) You must include a schedule for conducting initial and 
subsequent performance evaluations in the site-specific monitoring 
plan.
    (3) You must keep the site-specific monitoring plan on site for the 
life of the affected source or until the affected source is no longer 
subject to the provisions of this part, to be made available for 
inspection, upon request, by the Administrator. If you revise the site-
specific monitoring plan, you must keep previous (i.e., superseded) 
versions of the plan on site to be made available for inspection, upon 
request, by the Administrator, for a period of 5 years after each 
revision to the plan. You must include the program of corrective action 
required under Sec.  63.8(d)(2) in the plan.
    (d) For each bag leak detection system installed to comply with the 
requirements specified in Sec.  63.605(f), you must include the 
information specified in paragraphs (d)(1) and (2) of this section in 
the site-specific monitoring plan specified in paragraph (c) of this 
section.
    (1) Performance evaluation procedures and acceptance criteria 
(e.g., calibrations), including how the alarm set point will be 
established.
    (2) A corrective action plan describing corrective actions to be 
taken and the timing of those actions when the bag leak detection alarm 
sounds. Corrective actions may include, but are not limited to, the 
actions specified in paragraphs (d)(2)(i) through (vi) of this section.
    (i) Inspecting the fabric filter for air leaks, torn or broken bags 
or filter media, or any other conditions that may cause an increase in 
regulated material emissions.
    (ii) Sealing off defective bags or filter media.
    (iii) Replacing defective bags or filter media or otherwise 
repairing the control device.
    (iv) Sealing off a defective fabric filter compartment.
    (v) Cleaning the bag leak detection system probe or otherwise 
repairing the bag leak detection system.
    (vi) Shutting down the process controlled by the fabric filter.


Sec.  63.609  [Reserved]


Sec.  63.610  Exemption from new source performance standards.

    Any affected source subject to the provisions of this subpart is 
exempted from any otherwise applicable new source performance standard 
contained in 40 CFR part 60, subpart T, subpart U, or subpart NN. To be 
exempt, a source must have a current operating permit pursuant to title 
V of the Clean Air Act and the source must be in compliance with all 
requirements of this subpart. For each affected source, this exemption 
is effective upon the date that you demonstrate to the Administrator 
that the requirements of Sec. Sec.  63.605 and 63.606 have been met.


Sec.  63.611  Implementation and enforcement.

    (a) This subpart is implemented and enforced by the U.S. EPA, or a 
delegated authority such as the applicable state, local, or Tribal 
agency. If the U.S. EPA Administrator has delegated authority to a 
state, local, or Tribal agency, then that agency, in addition to the 
U.S. EPA, has the authority to implement and enforce this subpart. 
Contact the applicable U.S. EPA Regional Office to find out if 
implementation and enforcement of this subpart is delegated to a state, 
local, or Tribal agency.
    (b) The authorities specified in paragraphs (b)(1) through (5) of 
this section are retained by the Administrator of U.S. EPA and cannot 
be delegated to State, local, or Tribal agencies.
    (1) Approval of alternatives to the requirements in Sec. Sec.  
63.600, 63.602, 63.605, and 63.610.
    (2) Approval of requests under Sec. Sec.  63.7(e)(2)(ii) and 
63.7(f) for alternative requirements or major changes to the test 
methods specified in this subpart, as defined in Sec.  63.90.
    (3) Approval of requests under Sec.  63.8(f) for alternative 
requirements or major changes to the monitoring requirements specified 
in this subpart, as defined in Sec.  63.90.
    (4) Waiver or approval of requests under Sec.  63.10(f) for 
alternative requirements or major changes to the recordkeeping and 
reporting requirements specified in this subpart, as defined in Sec.  
63.90.
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

                Table 1 to Subpart AA of Part 63--Existing Source Phase 1 Emission Limits \a\ \b\
----------------------------------------------------------------------------------------------------------------
                                       You must meet the emission limits for the specified pollutant . . .
   For the following existing   --------------------------------------------------------------------------------
         sources . . .                                        Hydrogen            Total
                                    Total  fluorides          fluoride         particulate          Mercury
----------------------------------------------------------------------------------------------------------------
Wet-Process Phosphoric Acid      0.020 lb/ton of         .................  .................  .................
 Line.                            equivalent P2O5 feed.
Superphosphoric Acid Process     0.010 lb/ton of         .................  .................  .................
 Line.                            equivalent P2O5 feed.
Superphosphoric Acid Submerged   0.20 lb/ton of          .................  .................  .................
 Line with a Submerged            equivalent P2O5 feed.
 Combustion Process.
Phosphate Rock Dryer...........  ......................  .................  0.2150 lb/ton of   .................
                                                                             phosphate rock
                                                                             feed.
Phosphate Rock Calciner........  ......................  .................  0.181 g/dscm.....  .................
----------------------------------------------------------------------------------------------------------------
\a\ The phase 1 existing source compliance date is June 10, 2002.

[[Page 66574]]

 
\b\ During periods of startup and shutdown, for emission limits stated in terms of pounds of pollutant per ton
  of feed, you are subject to the work practice standards specified in Sec.   63.602(h).


 Table 1a to Subpart AA of Part 63--Existing Source Phase 2 Emission Limits and Work Practice Standards \a\ \b\
----------------------------------------------------------------------------------------------------------------
                                 You must meet the emission limits and work practice standards for the specified
                                                                 pollutant . . .
   For the following existing   --------------------------------------------------------------------------------
         sources . . .                                        Hydrogen            Total
                                    Total  fluorides          fluoride         particulate          Mercury
----------------------------------------------------------------------------------------------------------------
Wet-Process Phosphoric Acid      ......................  0.020 lb/ton of    .................  .................
 Line.                                                    equivalent P2O5
                                                          feed.
Superphosphoric Acid Process     ......................  0.010 lb/ton of    .................  .................
 Line.                                                    equivalent P2O5
                                                          feed.
Superphosphoric Acid Submerged   ......................  0.20 lb/ton of     .................  .................
 Line with a Submerged                                    equivalent P2O5
 Combustion Process.                                      feed.
Phosphate Rock Dryer...........  ......................  .................  0.2150 lb/ton of   .................
                                                                             phosphate rock
                                                                             feed.
Phosphate Rock Calciner........  ......................  Maintain a daily   0.181 g/dscm.....  0.014 mg/dscm @3%
                                                          average                               O2
                                                          calcination
                                                          temperature
                                                          below 1,600
                                                          [deg]F, and
                                                          route emissions
                                                          to an absorber.
----------------------------------------------------------------------------------------------------------------
\a\ The phase 2 existing source compliance dates apply at different times for different pollutants as specified
  in Sec.   63.602(a).
\b\ During periods of startup and shutdown, for emission limits stated in terms of pounds of pollutant per ton
  of feed, you are subject to the work practice standards specified in Sec.   63.602(h).


                  Table 2 to Subpart AA of Part 63--New Source Phase 1 Emission Limits \a\ \b\
----------------------------------------------------------------------------------------------------------------
                                       You must meet the emissions limits for the specified pollutant . . .
For the following new sources . --------------------------------------------------------------------------------
              . .                                             Hydrogen            Total
                                    Total  fluorides          fluoride         particulate          Mercury
----------------------------------------------------------------------------------------------------------------
Wet-Process Phosphoric Acid      0.0135 lb/ton of        .................  .................  .................
 Line.                            equivalent P2O5 feed.
Superphosphoric Acid Process     0.00870 lb/ton of       .................  .................  .................
 Line.                            equivalent P2O5 feed.
Phosphate Rock Dryer...........  ......................  .................  0.060 lb/ton of    .................
                                                                             phosphate rock
                                                                             feed.
Phosphate Rock Calciner........  ......................  .................  0.092 g/dscm.....  .................
----------------------------------------------------------------------------------------------------------------
\a\ The phase 1 new source compliance dates are based on date of construction or reconstruction as specified in
  Sec.   63.602(a).
\b\ During periods of startup and shutdown, for emission limits stated in terms of pounds of pollutant per ton
  of feed, you are subject to the work practice standards specified in Sec.   63.602(h).


        Table 2a to Subpart AA of Part 63--New Source Phase 2 Emission Limits and Work Practices \a\ \b\
----------------------------------------------------------------------------------------------------------------
                                      You must meet the emissions limits and work practice standards for the
                                                            specified pollutant . . .
For the following new sources . --------------------------------------------------------------------------------
              . .                                             Hydrogen            Total
                                    Total  fluorides          fluoride         particulate          Mercury
----------------------------------------------------------------------------------------------------------------
Wet-Process Phosphoric Acid      ......................  0.0135 lb/ton of   .................  .................
 Line.                                                    equivalent P2O5
                                                          feed.
Superphosphoric Acid Process     ......................  0.00870 lb/ton of  .................  .................
 Line.                                                    equivalent P2O5
                                                          feed.
Phosphate Rock Dryer...........  ......................  .................  0.060 lb/ton of    .................
                                                                             phosphate rock
                                                                             feed.
Phosphate Rock Calciner........  ......................  Maintain a daily   0.092 g/dscm.....  0.014 mg/dscm @3%
                                                          average                               O2
                                                          calcination
                                                          temperature
                                                          below 1,600
                                                          [deg]F, and
                                                          route emissions
                                                          to an absorber.
----------------------------------------------------------------------------------------------------------------
\a\ The phase 2 new source compliance dates are based on date of construction or reconstruction as specified in
  Sec.   63.602(a).
\b\ During periods of startup and shutdown, for emission limits stated in terms of pounds of pollutant per ton
  of feed, you are subject to the work practice standards specified in Sec.   63.602(h).


[[Page 66575]]


                   Table 3 to Subpart AA of Part 63--Monitoring Equipment Operating Parameters
----------------------------------------------------------------------------------------------------------------
                                                              And you must monitor . .
          You must . . .                    If . . .                      .                     And . . .
----------------------------------------------------------------------------------------------------------------
                     All Absorbers (Wet Scrubbers): Choose one of the following two options
----------------------------------------------------------------------------------------------------------------
Install a continuous parameter     You choose to monitor      Influent liquid flow....  ........................
 monitoring system (CPMS) for       only the influent liquid
 liquid flow at the inlet of the    flow, rather than the
 absorber.                          liquid-to-gas ratio.
Install CPMS for liquid and gas    You choose to monitor the  Liquid-to-gas ratio as    You must measure the gas
 flow at the inlet of the           liquid-to-gas ratio,       determined by dividing    stream by:
 absorber.                          rather than only the       the influent liquid      Measuring the gas stream
                                    influent liquid flow,      flow rate by the inlet    flow at the absorber
                                    and you want the ability   gas flow rate. The        inlet; or Using the
                                    to lower liquid flow       units of measure must     design blower capacity,
                                    with changes in gas flow.  be consistent with        with appropriate
                                                               those used to calculate   adjustments for
                                                               this ratio during the     pressure drop.
                                                               performance test, or
                                                               those found in the
                                                               engineering assessment
                                                               as specified in Sec.
                                                               63.605(d)(1)(ii), as
                                                               applicable.
----------------------------------------------------------------------------------------------------------------
               Absorbers (Wet Scrubbers): You must also choose one of the following three options
----------------------------------------------------------------------------------------------------------------
Install CPMS for pressure at the   You choose to monitor      Pressure drop through     You may measure the
 gas stream inlet and outlet of     pressure drop through      the absorber.             pressure of the inlet
 the absorber.                      the absorber, and your                               gas using amperage on
                                    pressure drop through                                the blower if a
                                    the absorber is greater                              correlation between
                                    than 5 inches of water.                              pressure and amperage
                                                                                         is established.
Install CPMS for temperature at    You choose to monitor      Exit gas temperature of   ........................
 the absorber gas stream outlet     exit gas temperature and   the absorber and inlet
 and pressure at the liquid inlet   inlet pressure of the      liquid pressure of the
 of the adsorber.                   liquid.                    absorber.
Install CPMS for temperature at    You choose to monitor      Exit gas temperature of   ........................
 the absorber gas stream outlet     temperature differential   the absorber and inlet
 and absorber gas stream inlet.     across the absorber.       gas temperature of the
                                                               absorber.
----------------------------------------------------------------------------------------------------------------
                                                   Condensers
----------------------------------------------------------------------------------------------------------------
Install a CPMS for temperature in  .........................  Temperature of the stack  ........................
 the stack exit gas.                                           exit gas.
----------------------------------------------------------------------------------------------------------------
                                                Sorbent Injection
----------------------------------------------------------------------------------------------------------------
Install a CPMS for flow rate.....  .........................  Sorbent injection rate..  ........................
Install a CPMS for flow rate.....  .........................  Sorbent injection         ........................
                                                               carrier gas flow rate.
----------------------------------------------------------------------------------------------------------------
                                         Wet Electrostatic Precipitators
----------------------------------------------------------------------------------------------------------------
Install secondary voltage meter..  You control mercury or     Secondary voltage.......  ........................
                                    metal HAP (particulate
                                    matter) using an
                                    electrostatic
                                    precipitator.
----------------------------------------------------------------------------------------------------------------


 Table 4 to Subpart AA of Part 63--Operating Parameters, Operating Limits and Data Monitoring, Recordkeeping and
                                             Compliance Frequencies
----------------------------------------------------------------------------------------------------------------
                                                       And you must monitor, record, and demonstrate continuous
                                  You must establish       compliance using these minimum frequencies . . .
   For the operating parameter       the following   -----------------------------------------------------------
 applicable to you, as specified   operating limit .                                            Data averaging
        in Table 3 . . .                  . .          Data measurement     Data recording        period for
                                                                                                  compliance
----------------------------------------------------------------------------------------------------------------
                                            Absorbers (Wet Scrubbers)
----------------------------------------------------------------------------------------------------------------
Influent liquid flow............  Minimum inlet       Continuous........  Every 15 minutes..  Daily.
                                   liquid flow.
Influent liquid flow rate and     Minimum influent    Continuous........  Every 15 minutes..  Daily.
 gas stream flow rate.             liquid-to-gas
                                   ratio.
Pressure drop...................  Pressure drop       Continuous........  Every 15 minutes..  Daily.
                                   range.
Exit gas temperature............  Maximum exit gas    Continuous........  Every 15 minutes..  Daily.
                                   temperature.
Inlet gas temperature...........  Minimum             Continuous........  Every 15 minutes..  Daily.
                                   temperature
                                   difference
                                   between inlet and
                                   exit gas.
Inlet liquid pressure...........  Minimum Inlet       Continuous........  Every 15 minutes..  Daily.
                                   liquid pressure.
----------------------------------------------------------------------------------------------------------------

[[Page 66576]]

 
                                                   Condensers
----------------------------------------------------------------------------------------------------------------
Gas temperature at the exit of    Maximum outlet gas  Continuous........  Every 15 minutes..  Daily.
 the condenser.                    temperature.
----------------------------------------------------------------------------------------------------------------
                                                Sorbent Injection
----------------------------------------------------------------------------------------------------------------
Sorbent injection rate..........  Minimum injection   Continuous........  Every 15 minutes..  Daily.
                                   rate.
----------------------------------------------------------------------------------------------------------------
Sorbent injection carrier gas     Minimum carrier     Continuous........  Every 15 minutes..  Daily.
 flow rate.                        gas flow rate.
----------------------------------------------------------------------------------------------------------------
                                                 Fabric Filters
----------------------------------------------------------------------------------------------------------------
Alarm time......................  Maximum alarm time  Continuous........  Each date and time  Maximum alarm time
                                   is not                                  of alarm start      specified in Sec.
                                   established on a                        and stop.
                                   site-specific                                               65.604(e)(1)(ix).
                                   basis but is
                                   specified in Sec.
 
                                   63.604(e)(1)(ix).
----------------------------------------------------------------------------------------------------------------
                                         Wet Electrostatic Precipitator
----------------------------------------------------------------------------------------------------------------
Secondary voltage...............  Secondary voltage   Continuous........  Every 15 minutes..  Daily.
                                   range.
----------------------------------------------------------------------------------------------------------------


    Table 5 to Subpart AA of Part 63--Calibration and Quality Control
     Requirements for Continuous Parameter Monitoring System (CPMS)
------------------------------------------------------------------------
                                                    And your calibration
     If you monitor this          Your accuracy     requirements are . .
       parameter . . .        requirements are . .            .
                                        .
------------------------------------------------------------------------
Temperature.................  1         Performance
                               percent over the      evaluation annually
                               normal range of       and following any
                               temperature           period of more than
                               measured or 2.8       24 hours throughout
                               degrees Celsius (5    which the
                               degrees               temperature
                               Fahrenheit),          exceeded the
                               whichever is          maximum rated
                               greater, for non-     temperature of the
                               cryogenic             sensor, or the data
                               temperature ranges.   recorder was off
                                                     scale.
                              2.5       Visual inspections
                               percent over the      and checks of CPMS
                               normal range of       operation every 3
                               temperature           months, unless the
                               measured or 2.8       CPMS has a
                               degrees Celsius (5    redundant
                               degrees               temperature sensor.
                               Fahrenheit),         Selection of a
                               whichever is          representative
                               greater, for          measurement
                               cryogenic             location.
                               temperature ranges.
Flow Rate...................  5         Performance
                               percent over the      evaluation annually
                               normal range of       and following any
                               flow measured or      period of more than
                               1.9 liters per        24 hours throughout
                               minute (0.5 gallons   which the flow rate
                               per minute),          exceeded the
                               whichever is          maximum rated flow
                               greater, for liquid   rate of the sensor,
                               flow rate.            or the data
                                                     recorder was off
                                                     scale.
                              5         Checks of all
                               percent over the      mechanical
                               normal range of       connections for
                               flow measured or      leakage monthly.
                               280 liters per       Visual inspections
                               minute (10 cubic      and checks of CPMS
                               feet per minute),     operation every 3
                               whichever is          months, unless the
                               greater, for gas      CPMS has a
                               flow rate.            redundant flow
                                                     sensor.
                              5         Selection of a
                               percent over the      representative
                               normal range          measurement
                               measured for mass     location where
                               flow rate.            swirling flow or
                                                     abnormal velocity
                                                     distributions due
                                                     to upstream and
                                                     downstream
                                                     disturbances at the
                                                     point of
                                                     measurement are
                                                     minimized.
Pressure....................  5         Checks for
                               percent over the      obstructions (e.g.,
                               normal range          pressure tap
                               measured or 0.12      pluggage) at least
                               kilopascals (0.5      once each process
                               inches of water       operating day.
                               column), whichever   Performance
                               is greater.           evaluation annually
                                                     and following any
                                                     period of more than
                                                     24 hours throughout
                                                     which the pressure
                                                     exceeded the
                                                     maximum rated
                                                     pressure of the
                                                     sensor, or the data
                                                     recorder was off
                                                     scale.
                                                    Checks of all
                                                     mechanical
                                                     connections for
                                                     leakage monthly.
                                                     Visual inspection
                                                     of all components
                                                     for integrity,
                                                     oxidation and
                                                     galvanic corrosion
                                                     every 3 months,
                                                     unless the CPMS has
                                                     a redundant
                                                     pressure sensor.
                                                    Selection of a
                                                     representative
                                                     measurement
                                                     location that
                                                     minimizes or
                                                     eliminates
                                                     pulsating pressure,
                                                     vibration, and
                                                     internal and
                                                     external corrosion.

[[Page 66577]]

 
Sorbent Injection Rate......  5         Performance
                               percent over the      evaluation
                               normal range          annually.
                               measured.            Visual inspections
                                                     and checks of CPMS
                                                     operation every 3
                                                     months, unless the
                                                     CPMS has a
                                                     redundant sensor.
                                                    Select a
                                                     representative
                                                     measurement
                                                     location that
                                                     provides
                                                     measurement of
                                                     total sorbent
                                                     injection.
Secondary voltage...........  1kV.
------------------------------------------------------------------------


 Appendix A to Subpart AA of Part 63--Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart
                                                       AA
----------------------------------------------------------------------------------------------------------------
           40 CFR citation                   Requirement         Applies to subpart AA           Comment
----------------------------------------------------------------------------------------------------------------
Sec.   63.1(a)(1) through (4)........  General Applicability..  Yes....................  None.
Sec.   63.1(a)(5)....................  .......................  No.....................  [Reserved].
Sec.   63.1(a)(6)....................  Contact information....  Yes....................  None.
Sec.   63.1(a)(7)-(9)................  .......................  No.....................  [Reserved].
Sec.   63.1(a)(10) through (12)......  Time periods...........  Yes....................  None.
Sec.   63.1(b).......................  Initial Applicability    Yes....................  None.
                                        Determination.
Sec.   63.1(c)(1)....................  Applicability After      Yes....................  None.
                                        Standard Established.
Sec.   63.1(c)(2)....................  Permits................  Yes....................  Some plants may be area
                                                                                          sources.
Sec.   63.1(c)(3)-(4)................  .......................  No.....................  [Reserved].
Sec.   63.1(c)(5)....................  Area to Major source     Yes....................  None.
                                        change.
Sec.   63.1(d).......................  .......................  No.....................  [Reserved].
Sec.   63.1(e).......................  Applicability of Permit  Yes....................  None.
                                        Program.
Sec.   63.2..........................  Definitions............  Yes....................  Additional definitions
                                                                                          in Sec.   63.601.
Sec.   63.3..........................  Units and Abbreviations  Yes....................  None.
Sec.   63.4(a)(1) and (2)............  Prohibited Activities..  Yes....................  None.
Sec.   63.4(a)(3) through (5)........  .......................  No.....................  [Reserved].
Sec.   63.4(b) and (c)...............  Circumvention/           Yes....................  None.
                                        Fragmentation.
Sec.   63.5(a).......................  Construction/            Yes....................  None.
                                        Reconstruction
                                        Applicability.
Sec.   63.5(b)(1)....................  Existing, New,           Yes....................  None.
                                        Reconstructed Sources
                                        Requirements.
Sec.   63.5(b)(2)....................  .......................  No.....................  [Reserved].
Sec.   63.5(b)(3), (4), and (6)......  Construction/            Yes....................  None.
                                        Reconstruction
                                        approval and
                                        notification.
Sec.   63.5(b)(5)....................  .......................  No.....................  [Reserved]
Sec.   63.5(c).......................  .......................  No.....................  [Reserved].
Sec.   63.5(d).......................  Application for          Yes....................  None.
                                        Approval of
                                        Construction/
                                        Reconstruction.
Sec.   63.5(e).......................  Approval of              Yes....................  None.
                                        Construction/
                                        Reconstruction.
Sec.   63.5(f).......................  Approval of              Yes....................  None.
                                        Construction/
                                        Reconstruction Based
                                        on State Review.
Sec.   63.6(a).......................  Compliance with          Yes....................  None.
                                        Standards and
                                        Maintenance
                                        Applicability.
Sec.   63.6(b)(1) through (5)........  New and Reconstructed    Yes....................  See also Sec.   63.602.
                                        Sources Dates.
Sec.   63.6(b)(6)....................  .......................  No.....................  [Reserved].
Sec.   63.6(b)(7)....................  Area to major source     Yes....................  None.
                                        change.
Sec.   63.6(c)(1) and (2)............  Existing Sources Dates.  Yes....................  Sec.   63.602 specifies
                                                                                          dates.
Sec.   63.6(c)(3) and (4)............  .......................  No.....................  [Reserved].
Sec.   63.6(c)(5)....................  Area to major source     Yes....................  None.
                                        change.
Sec.   63.6(d).......................  .......................  No.....................  [Reserved].
Sec.   63.6(e)(1)(i) and (ii)........  Operation & Maintenance  No.....................  See Sec.   63.608(b)
                                        Requirements.                                     for general duty
                                                                                          requirement.
Sec.   63.6(e)(iii)..................  .......................  Yes....................  None.
Sec.   63.6(e)(2)....................  .......................  No.....................  [Reserved].
Sec.   63.6(e)(3)....................  Startup, Shutdown, and   No.....................  None.
                                        Malfunction Plan.
Sec.   63.6(f).......................  Compliance with          No.....................  See general duty at
                                        Emission Standards.                               Sec.   63.608(b).
Sec.   63.6(g).......................  Alternative Standard...  Yes....................  None.
Sec.   63.6(h).......................  Compliance with Opacity/ No.....................  Subpart AA does not
                                        VE Standards.                                     include VE/opacity
                                                                                          standards.
Sec.   63.6(i)(1) through (14).......  Extension of Compliance  Yes....................  None.
Sec.   63.6(i)(15)...................  .......................  No.....................  [Reserved].
Sec.   63.6(i)(16)...................  .......................  Yes....................  None.

[[Page 66578]]

 
Sec.   63.6(j).......................  Exemption from           Yes....................  None.
                                        Compliance.
Sec.   63.7(a).......................  Performance Test         Yes....................  None.
                                        Requirements
                                        Applicability.
Sec.   63.7(b).......................  Notification...........  Yes....................  None.
Sec.   63.7(c).......................  Quality Assurance/Test   Yes....................  None.
                                        Plan.
Sec.   63.7(d).......................  Testing Facilities.....  Yes....................  None.
Sec.   63.7(e)(1)....................  Conduct of Tests;        No.....................  Sec.   63.606 specifies
                                        startup, shutdown, and                            additional
                                        malfunction provisions.                           requirements.
Sec.   63.7(e)(2) through (4)........  Conduct of Tests.......  Yes....................  Sec.   63.606 specifies
                                                                                          additional
                                                                                          requirements.
Sec.   63.7(f).......................  Alternative Test Method  Yes....................  None.
Sec.   63.7(g).......................  Data Analysis..........  Yes....................  None.
Sec.   63.7(h).......................  Waiver of Tests........  Yes....................  None.
Sec.   63.8(a).......................  Monitoring Requirements  Yes....................  None.
                                        Applicability.
Sec.   63.8(b).......................  Conduct of Monitoring..  Yes....................  None.
Sec.   63.8(c)(1)(i).................  General duty to          No.....................  See 63.608(b) for
                                        minimize emissions and                            general duty
                                        CMS operation.                                    requirement.
Sec.   63.8(c)(1)(ii)................  .......................  Yes....................  None.
Sec.   63.8(c)(1)(iii)...............  Requirement to develop   No.....................  None.
                                        SSM Plan for CMS.
Sec.   63.8(c)(2) through (4)........  CMS Operation/           Yes....................  None.
                                        Maintenance.
Sec.   63.8(c)(5)....................  COMS Operation.........  No.....................  Subpart AA does not
                                                                                          require COMS.
Sec.   63.8(c)(6) through(8).........  CMS requirements.......  Yes....................  None.
Sec.   63.8(d)(1) and (2)............  Quality Control........  Yes....................  None.
Sec.   63.8(d)(3)....................  Written procedure for    No.....................  See Sec.   63.608 for
                                        CMS.                                              requirement.
Sec.   63.8(e).......................  CMS Performance          Yes....................  None.
                                        Evaluation.
Sec.   63.8(f)(1) through (5)........  Alternative Monitoring   Yes....................  None.
                                        Method.
Sec.   63.8(f)(6)....................  Alternative to RATA      Yes....................  None.
                                        Test.
Sec.   63.8(g)(1)....................  Data Reduction.........  Yes....................  None.
Sec.   63.8(g)(2)....................  .......................  Yes....................  None.
Sec.   63.8(g)(3) through (5)........  .......................  Yes....................  None.
Sec.   63.9(a).......................  Notification             Yes....................  None.
                                        Requirements
                                        Applicability.
Sec.   63.9(b).......................  Initial Notifications..  Yes....................  None.
Sec.   63.9(c).......................  Request for Compliance   Yes....................  None.
                                        Extension.
Sec.   63.9(d).......................  New Source Notification  Yes....................  None.
                                        for Special Compliance
                                        Requirements.
Sec.   63.9(e).......................  Notification of          Yes....................  None.
                                        Performance Test.
Sec.   63.9(f).......................  Notification of VE/      No.....................  Subpart AA does not
                                        Opacity Test.                                     include VE/opacity
                                                                                          standards.
Sec.   63.9(g).......................  Additional CMS           Yes....................  Subpart AA does not
                                        Notifications.                                    require CMS
                                                                                          performance
                                                                                          evaluation, COMS, or
                                                                                          CEMS.
Sec.   63.9(h)(1) through (3)........  Notification of          Yes....................  None.
                                        Compliance Status.
Sec.   63.9(h)(4)....................  .......................  No.....................  [Reserved].
Sec.   63.9(h)(5) and (6)............  .......................  Yes....................  None.
Sec.   63.9(i).......................  Adjustment of Deadlines  Yes....................  None.
Sec.   63.9(j).......................  Change in Previous       Yes....................  None.
                                        Information.
Sec.   63.10(a)......................  Recordkeeping/Reporting- Yes....................  None.
                                        Applicability.
Sec.   63.10(b)(1)...................  General Recordkeeping    Yes....................  None.
                                        Requirements.
Sec.   63.10(b)(2)(i)................  Startup or shutdown      No.....................  None.
                                        duration.
Sec.   63.10(b)(2)(ii)...............  Malfunction............  No.....................  See Sec.   63.607 for
                                                                                          recordkeeping and
                                                                                          reporting requirement.
Sec.   63.10(b)(2)(iii)..............  Maintenance records....  Yes....................  None.
Sec.   63.10(b)(2)(iv) and (v).......  Startup, shutdown,       No.....................  None.
                                        malfunction actions.
Sec.   63.10(b)(2)(vi) through (xiv).  General Recordkeeping    Yes....................  None.
                                        Requirements.
Sec.   63.10(b)(3)...................  General Recordkeeping    Yes....................  None.
                                        Requirements.
Sec.   63.10(c)(1)...................  Additional CMS           Yes....................  None.
                                        Recordkeeping.
Sec.   63.10(c)(2) through (4).......  .......................  No.....................  [Reserved].
Sec.   63.10(c)(5)...................  .......................  Yes....................  None.
Sec.   63.10(c)(6)...................  .......................  Yes....................  None.
Sec.   63.10(c)(7) and (8)...........  .......................  Yes....................  None.
Sec.   63.10(c)(9)...................  .......................  No.....................  [Reserved].
Sec.   63.10(c)(10) through (13).....  .......................  Yes....................  None.
Sec.   63.10(c)(14)..................  .......................  Yes....................  None.
Sec.   63.10(c)(15)..................  Startup Shutdown         No.....................  None.
                                        Malfunction Plan
                                        Provisions.
Sec.   63.10(d)(1)...................  General Reporting        Yes....................  None.
                                        Requirements.
Sec.   63.10(d)(2)...................  Performance Test         Yes....................  None.
                                        Results.
Sec.   63.10(d)(3)...................  Opacity or VE            No.....................  Subpart AA does not
                                        Observations.                                     include VE/opacity
                                                                                          standards.

[[Page 66579]]

 
Sec.   63.10(d)(4)...................  Progress Reports.......  Yes....................  None.
Sec.   63.10(d)(5)...................  Startup, Shutdown, and   No.....................  See Sec.   63.607 for
                                        Malfunction Reports.                              reporting of excess
                                                                                          emissions.
Sec.   63.10(e)(1) and (2)...........  Additional CMS Reports.  Yes....................  None.
Sec.   63.10(e)(3)...................  Excess Emissions/CMS     Yes....................  None.
                                        Performance Reports.
Sec.   63.10(e)(4)...................  COMS Data Reports......  No.....................  Subpart AA does not
                                                                                          require COMS.
Sec.   63.10(f)......................  Recordkeeping/Reporting  Yes....................  None.
                                        Waiver.
Sec.   63.11.........................  Control Device and Work  Yes....................  None.
                                        Practice Requirements.
Sec.   63.12.........................  State Authority and      Yes....................  None.
                                        Delegations.
Sec.   63.13.........................  Addresses..............  Yes....................  None.
Sec.   63.14.........................  Incorporation by         Yes....................  None.
                                        Reference.
Sec.   63.15.........................  Information              Yes....................  None.
                                        Availability/
                                        Confidentiality.
Sec.   63.16.........................  Performance Track        No.....................  Terminated.
                                        Provisions.
----------------------------------------------------------------------------------------------------------------

0
21. Part 63 is amended by revising subpart BB to read as follows:

Subpart BB--National Emission Standards for Hazardous Air 
Pollutants From Phosphate Fertilizers Production Plants

Sec.
63.620 Applicability.
63.621 Definitions.
63.622 Standards and compliance dates.
63.623 [Reserved]
63.624 [Reserved]
63.625 Operating and monitoring requirements.
63.626 Performance tests and compliance provisions.
63.627 Notification, recordkeeping, and reporting requirements.
63.628 General requirements and applicability of part 63 general 
provisions.
63.629 Miscellaneous requirements.
63.630 [Reserved]
63.631 Exemption from new source performance standards.
63.632 Implementation and enforcement.
Table 1 to Subpart BB of Part 63--Existing Source Phase 1 Emission 
Limits
Table 1a to Subpart BB of Part 63--Existing Source Phase 2 Emission 
Limits
Table 2 to Subpart BB of Part 63--New Source Phase 1 Emission Limits
Table 2a to Subpart BB of Part 63--New Source Phase 2 Emission 
Limits
Table 3 to Subpart BB of Part 63--Monitoring Equipment Operating 
Parameters
Table 4 to Subpart BB of Part 63--Operating Parameters, Operating 
Limits and Data Monitoring, Recordkeeping and Compliance Frequencies
Table 5 to Subpart BB of Part 63--Calibration and Quality Control 
Requirements for Continuous Parameter Monitoring Systems (CPMS)
Appendix A to Subpart BB of Part 63--Applicability of General 
Provisions (40 CFR Part 63, Subpart A) to Subpart BB


Sec.  63.620  Applicability.

    (a) Except as provided in paragraphs (c) and (d) of this section, 
you are subject to the requirements of this subpart if you own or 
operate a phosphate fertilizer production plant that is a major source 
as defined in Sec.  63.2. You must comply with the emission 
limitations, work practice standards, and operating parameter 
requirements specified in this subpart at all times.
    (b) The requirements of this subpart apply to emissions of 
hazardous air pollutants (HAP) emitted from the following affected 
sources at a phosphate fertilizer production plant:
    (1) Each diammonium and/or monoammonium phosphate process line and 
any process line that produces a reaction product of ammonia and 
phosphoric acid.
    (2) Each granular triple superphosphate process line.
    (3) Each granular triple superphosphate storage building.
    (c) The requirements of this subpart do not apply to a phosphate 
fertilizer production plant that is an area source as defined in Sec.  
63.2.
    (d) The provisions of this subpart do not apply to research and 
development facilities as defined in Sec.  63.621.


Sec.  63.621  Definitions.

    Terms used in this subpart are defined in Sec.  63.2 of the Clean 
Air Act and in this section as follows:
    Diammonium and/or monoammonium phosphate process line means any 
process line manufacturing granular diammonium and/or monoammonium 
phosphate by reacting ammonia with phosphoric acid that has been 
derived from or manufactured by reacting phosphate rock and acid. A 
diammonium and/or monoammonium phosphate process line includes, but is 
not limited to: Reactors, granulators, dryers, coolers, cooling towers, 
screens, and mills.
    Equivalent P2O5 feed means the quantity of phosphorus, expressed as 
phosphorus pentoxide (P2O5), fed to the process.
    Equivalent P2O5 stored means the quantity of phosphorus, expressed 
as phosphorus pentoxide, being cured or stored in the affected 
facility.
    Exceedance means a departure from an indicator range established 
for monitoring under this subpart, consistent with any averaging period 
specified for averaging the results of the monitoring.
    Existing source depends on the date that construction or 
reconstruction of an affected source commenced. A process line that 
produces a reaction product of ammonia and phosphoric acid (e.g., 
diammonium and/or monoammonium phosphate process line), granular triple 
superphosphate process line, or granular triple superphosphate storage 
is an existing source if construction or reconstruction of the affected 
source commenced on or before December 27, 1996.
    Fresh granular triple superphosphate means granular triple 
superphosphate produced within the preceding 72 hours.
    Phosphate fertilizer process line or production plant means any 
process line or production plant that manufactures a phosphate 
fertilizer by reacting phosphoric acid with ammonia.
    Granular triple superphosphate process line means any process line, 
not including storage buildings, that manufactures granular triple 
superphosphate by reacting phosphate rock with phosphoric acid. A 
granular triple superphosphate process line

[[Page 66580]]

includes, but is not limited to: Mixers, curing belts (dens), reactors, 
granulators, dryers, coolers, cooling towers, screens, and mills.
    Granular triple superphosphate storage building means any building 
curing or storing fresh granular triple superphosphate. A granular 
triple superphosphate storage building includes, but is not limited to: 
Storage or curing buildings, conveyors, elevators, screens, and mills.
    New source depends on the date that construction or reconstruction 
of an affected source commences. A process line that produces a 
reaction product of ammonia and phosphoric acid (e.g., diammonium and/
or monoammonium phosphate process line), granular triple superphosphate 
process line, or granular triple superphosphate storage is a new source 
if construction or reconstruction of the affected source commenced 
after December 27, 1996.
    Research and development facility means research or laboratory 
operations whose primary purpose is to conduct research and development 
into new processes and products, where the operations are under the 
close supervision of technically trained personnel, and where the 
facility is not engaged in the manufacture of products for commercial 
sale in commerce or other off-site distribution, except in a de minimis 
manner.
    Total fluorides means elemental fluorine and all fluoride 
compounds, including the HAP hydrogen fluoride, as measured by 
reference methods specified in 40 CFR part 60, appendix A, Method 13 A 
or B, or by equivalent or alternative methods approved by the 
Administrator pursuant to Sec.  63.7(f).


Sec.  63.622  Standards and compliance dates.

    (a) On and after the date on which the initial performance test 
specified in Sec. Sec.  63.7 and 63.626 is required to be completed, 
for each process line that produces a reaction product of ammonia and 
phosphoric acid (e.g., diammonium and/or monoammonium phosphate process 
line), granular triple superphosphate process line, and granular triple 
superphosphate storage building, you must comply with the emission 
limits as specified in paragraphs (a)(1) through (3) of this section. 
If a process line contains more than one emission point, you must sum 
the emissions from all emission points in a process line to determine 
compliance with the specified emission limits.
    (1) For each existing process line that produces a reaction product 
of ammonia and phosphoric acid (e.g., diammonium and/or monoammonium 
phosphate process line), granular triple superphosphate process line, 
and granular triple superphosphate storage building that commenced 
construction or reconstruction on or before December 27, 1996, you must 
comply with the emission limits specified in Table 1 to this subpart 
beginning on June 10, 2002 and ending on [date one year after the date 
of publication of the final rule in the Federal Register]. Beginning on 
[date one year after the date of publication of the final rule in the 
Federal Register], the emission limits specified in Table 1 to this 
subpart no longer apply, and you must comply with the emission limits 
specified in Table 1a to this subpart.
    (2) For each new process line that produces a reaction product of 
ammonia and phosphoric acid (e.g., diammonium and/or monoammonium 
phosphate process line), granular triple superphosphate process line, 
and granular triple superphosphate storage building that commences 
construction or reconstruction after December 27, 1996 and on or before 
[date of publication of the final rule in the Federal Register], you 
must comply with the emission limits specified in Table 2 to this 
subpart beginning at startup or on June 10, 1999, whichever is later, 
and ending on [date one year after the date of publication of the final 
rule in the Federal Register]. Beginning on [date one year after the 
date of publication of the final rule in the Federal Register], the 
emission limits specified in Table 2 to this subpart no longer apply, 
and you must comply with the emission limits specified in Table 2a to 
this subpart beginning on [date one year after the date of publication 
of the final rule in the Federal Register] or immediately upon startup, 
whichever is later.
    (3) For each new process line that produces a reaction product of 
ammonia and phosphoric acid (e.g., diammonium and/or monoammonium 
phosphate process line), granular triple superphosphate process line, 
and granular triple superphosphate storage building that commences 
construction or reconstruction after [date of publication of the final 
rule in the Federal Register], you must comply with the emission limits 
specified in Table 2a to this subpart immediately upon startup.
    (b) You must not ship fresh granular triple superphosphate from 
your granular triple superphosphate storage building.
    (c) You must not introduce into any evaporative cooling tower any 
liquid effluent from any wet scrubbing device installed to control 
emissions from process equipment.
    (d) To demonstrate compliance with any emission limits specified in 
paragraph (a) of this section during periods of startup and shutdown, 
you must begin operation of any control device(s) being used at the 
affected source prior to introducing any feed into the affected source. 
You must continue operation of the control device(s) through the 
shutdown period until all feed material has been processed through the 
affected source.


Sec.  63.623  [Reserved]


Sec.  63.624  [Reserved]


Sec.  63.625  Operating and monitoring requirements.

    (a) For each process line that produces a reaction product of 
ammonia and phosphoric acid (e.g., diammonium and/or monoammonium 
phosphate process line), or granular triple superphosphate process line 
subject to the provisions of this subpart, you must comply with the 
monitoring requirements specified in paragraphs (a)(1) and (2) of this 
section.
    (1) Install, calibrate, maintain, and operate a continuous 
monitoring system (CMS) according to your site-specific monitoring plan 
specified in Sec.  63.628(c). The CMS must have an accuracy of 5 percent over its operating range and must determine and 
permanently record the mass flow of phosphorus-bearing material fed to 
the process.
    (2) Maintain a daily record of equivalent 
P2O5 feed. Calculate the equivalent 
P2O5 feed by determining the total mass rate in 
metric ton/hour of phosphorus bearing feed using the procedures 
specified in Sec.  63.626(f)(3).
    (b) For each granular triple superphosphate storage building 
subject to the provisions of this subpart, you must maintain an 
accurate record of the mass of granular triple superphosphate in 
storage to permit the determination of the amount of equivalent 
P2O5 stored.
    (c) For each granular triple superphosphate storage building 
subject to the provisions of this subpart, you must comply with the 
requirements specified in paragraphs (c)(1) and (2) of this section.
    (1) Maintain a daily record of total equivalent 
P2O5 stored by multiplying the percentage 
P2O5 content, as determined by Sec.  
63.626(f)(3)(ii), by the total mass of granular triple superphosphate 
stored as specified in paragraph (b) of this section.
    (2) Develop for approval by the Administrator a site-specific 
methodology including sufficient recordkeeping for the purposes of

[[Page 66581]]

demonstrating compliance with Sec.  63.622(b).
    (d) If you use a control device(s) to comply with the emission 
limits specified in Tables 1, 1a, 2, or 2a of this subpart, you must 
install a continuous parameter monitoring system (CPMS) and comply with 
the requirements specified in paragraphs (d)(1) through (4) of this 
section.
    (1) You must monitor the operating parameter(s) applicable to the 
control device that you use as specified in Table 3 to this subpart and 
establish the applicable limit or range for the operating parameter 
limit as specified in paragraphs (d)(1)(i) and (ii) of this section, as 
applicable.
    (i) Except as specified in paragraph (d)(1)(ii) of this section, 
determine the value(s) as the arithmetic average of operating parameter 
measurements recorded during with the three test runs conducted for the 
most recent performance test.
    (ii) If you use an absorber to comply with the emission limits in 
Table 1, 1a, 2, or 2a to this subpart and you monitor pressure drop 
across each absorber, you must establish allowable ranges using the 
methodology specified in paragraphs (d)(1)(ii)(A) and (B) of this 
section.
    (A) The allowable range for the daily averages of the pressure drop 
across each absorber is 20 percent of the baseline average 
value determined in paragraph (d)(1)(i) of this section. The 
Administrator retains the right to reduce the 20 percent 
adjustment to the baseline average values of operating ranges in those 
instances where performance test results indicate that a source's level 
of emissions is near the value of an applicable emissions standard. 
However, the adjustment must not be reduced to less than 10 
percent under any instance.
    (B) As an alternative to paragraph (d)(1)(ii)(A) of this section, 
you may establish, and provide to the Administrator for approval, 
allowable ranges for the daily averages of the pressure drop across an 
absorber for the purpose of assuring compliance with this subpart. You 
must establish the allowable ranges based on the baseline average 
values recorded during previous performance tests or the results of 
performance tests conducted specifically for the purposes of this 
paragraph. You must conduct all performance tests using the methods 
specified in Sec.  63.626. You must certify that the control devices 
and processes have not been modified since the date of the performance 
test from which you obtained the data used to establish the allowable 
ranges. You must request and obtain approval of the Administrator for 
changes to the allowable ranges. When a source using the methodology of 
this paragraph is retested, you must determine new allowable ranges of 
baseline average values unless the retest indicates no change in the 
operating parameters outside the previously established ranges.
    (2) You must monitor, record, and demonstrate continuous compliance 
using the minimum frequencies specified in Table 4 to this subpart.
    (3) You must comply with the calibration and quality control 
requirements that are applicable to the operating parameter(s) you 
monitor as specified in Table 5 to this subpart.
    (4) If you use a fabric filter system to comply with the emission 
limits specified in Table 1, 1a, 2, or 2a to this subpart, the system 
must meet the requirements for fabric filters specified in paragraph 
(e) of this section.
    (e) If you use a fabric filter system to comply with the emission 
limits specified in Table 1, 1a, 2, or 2a to this subpart, the fabric 
filter must be equipped with a bag leak detection system that is 
installed, calibrated, maintained and continuously operated according 
to the requirements in paragraphs (e)(1) through (10) of this section.
    (1) Install a bag leak detection sensor(s) in a position(s) that 
will be representative of the relative or absolute particulate matter 
loadings for each exhaust stack, roof vent, or compartment (e.g., for a 
positive-pressure fabric filter) of the fabric filter.
    (2) Use a bag leak detection system certified by the manufacturer 
to be capable of detecting particulate matter emissions at 
concentrations of 1 milligram per actual cubic meter (0.00044 grains 
per actual cubic feet) or less.
    (3) Use a bag leak detection system equipped with a device to 
continuously record the output signal from the system sensor.
    (4) Use a bag leak detection system equipped with a system that 
will trigger an alarm when an increase in relative particulate material 
emissions over a preset level is detected. The alarm must be located 
such that the alert is observed readily by plant operating personnel.
    (5) Install a bag leak detection system in each compartment or cell 
for positive-pressure fabric filter systems that do not duct all 
compartments or cells to a common stack. Install a bag leak detector 
downstream of the fabric filter if a negative-pressure or induced-air 
filter is used. If multiple bag leak detectors are required, the 
system's instrumentation and alarm may be shared among detectors.
    (6) Calibration of the bag leak detection system must, at a 
minimum, consist of establishing the baseline output level by adjusting 
the range and the averaging period of the device and establishing the 
alarm set points and the alarm delay time.
    (7) After initial adjustment, you must not adjust the sensitivity 
or range, averaging period, alarm set points or alarm delay time, 
except as established in your site-specific monitoring plan required in 
Sec.  63.628(c). In no event may the sensitivity be increased more than 
100 percent or decreased by more than 50 percent over a 365-day period 
unless such adjustment follows a complete inspection of the fabric 
filter system that demonstrates that the system is in good operating 
condition.
    (8) Operate and maintain each fabric filter and bag leak detection 
system such that the alarm does not sound more than 5 percent of the 
operating time during a 6-month period. If the alarm sounds more than 5 
percent of the operating time during a 6-month period, it is considered 
an operating parameter exceedance. Calculate the alarm time (i.e., time 
that the alarm sounds) as specified in paragraphs (e)(8)(i) through 
(iv) of this section.
    (i) If inspection of the fabric filter demonstrates that corrective 
action is not required, the alarm duration is not counted in the alarm 
time calculation.
    (ii) If corrective action is required, each alarm time is counted 
as a minimum of 1 hour.
    (iii) If it takes longer than 1 hour to initiate corrective action, 
each alarm time (i.e., time that the alarm sounds) is counted as the 
actual amount of time taken by you to initiate corrective action.
    (9) If the alarm on a bag leak detection system is triggered, you 
must initiate procedures within 1 hour of an alarm to identify the 
cause of the alarm and then initiate corrective action, as specified in 
Sec.  63.628(d)(2), no later than 48 hours after an alarm. Failure to 
take these actions within the prescribed time periods is considered a 
violation.
    (10) Retain records of any bag leak detection system alarm, 
including the date, time, duration, and the percent of the total 
operating time during each 6-month period that the alarm triggers, with 
a brief explanation of the cause of the alarm, the corrective action 
taken, and the schedule and duration of the corrective action.

[[Page 66582]]

Sec.  63.626  Performance tests and compliance provisions.

    (a) You must conduct an initial performance test to demonstrate 
compliance with the emission limits specified in Tables 1, 1a, 2, and 
2a to this subpart, on or before the applicable compliance date 
specified in Sec.  63.622.
    (b) After you conduct the initial performance test specified in 
paragraph (a) of this section, you must conduct an annual performance 
test no more than 13 months after the date the previous performance 
test was conducted.
    (c) For affected sources (as defined in Sec.  63.620) that have not 
operated since the previous annual performance test was conducted and 
more than 1 year has passed since the previous performance test, you 
must conduct a performance test no later than 180 days after the re-
start of the affected source according to the applicable provisions in 
Sec.  63.7(a)(2).
    (d) You must conduct the performance tests specified in this 
section at maximum representative operating conditions for the process. 
Maximum representative operating conditions means process operating 
conditions that are likely to recur and that result in the flue gas 
characteristics that are the most difficult for reducing emissions of 
the regulated pollutant(s) by the control device used. The most 
difficult condition for the control device may include, but is not 
limited to, the highest HAP mass loading rate to the control device or 
the highest HAP mass loading rate of constituents that approach the 
limits of solubility for scrubbing media. Operations during startup, 
shutdown, and malfunction do not constitute representative operating 
conditions for purposes of conducting a performance test. You must 
record the process information that is necessary to document the 
operating conditions during the test and include in such record an 
explanation to support that such conditions represent maximum 
representative operating conditions. Upon request, you must make 
available to the Administrator such records as may be necessary to 
determine the conditions of performance tests.
    (e) In conducting all performance tests, you must use as reference 
methods and procedures the test methods in 40 CFR part 60, appendix A, 
or other methods and procedures as specified in this section, except as 
provided in Sec.  63.7(f).
    (f) For each process line that produces a reaction product of 
ammonia and phosphoric acid (e.g., diammonium and/or monoammonium 
phosphate process line), and granular triple superphosphate process 
line, you must determine compliance with the applicable total fluorides 
or hydrogen fluoride standards specified in Tables 1, 1a, 2, and 2a to 
this subpart as specified in paragraphs (f)(1) through (3) of this 
section.
    (1) Compute the emission rate (E) of total fluorides or hydrogen 
fluoride for each run using Equation BB-1:
[GRAPHIC] [TIFF OMITTED] TP07NO14.003

Where:

E = Emission rate of total fluorides or hydrogen fluoride, gram/
metric ton (pound/ton) of equivalent P2O5 
feed.
Ci = Concentration of total fluorides or hydrogen fluoride from 
emission point ``i,'' milligram/dry standard cubic meter (milligram/
dry standard cubic feet).
Qi = Volumetric flow rate of effluent gas from emission point ``i,'' 
dry standard cubic meter/hour (dry standard cubic feet/hour).
N = Number of emission points associated with the affected facility.
P = Equivalent P2O5 feed rate, metric ton/hour 
(ton/hour).
K = Conversion factor, 1,000 milligram/gram (453,600 milligram/
pound).

    (2) You must use the test methods and procedures as specified in 
paragraphs (f)(2)(i) or (f)(2)(ii) of this section.
    (i) You must use Method 13A or 13B (40 CFR part 60, appendix A) to 
determine the total fluorides concentration (Ci) and the 
volumetric flow rate (Qi) of the effluent gas at each 
emission point. The sampling time for each run at each emission point 
must be at least 60 minutes. The sampling volume for each run at each 
emission point must be at least 0.85 dscm (30 dscf). If Method 13B is 
used, the fusion of the filtered material described in Section 7.3.1.2 
and the distillation of suitable aliquots of containers 1 and 2, 
described in section 7.3.3 and 7.3.4 in Method 13A, may be omitted.
    (ii) You must use Method 320 at 40 CFR part 63, appendix A to 
determine the hydrogen fluoride concentration (Ci) at each 
emission point. The sampling time for each run at each emission point 
must be at least 60 minutes. You must use Method 2 at 40 CFR part 60, 
Appendix A-1 to determine the volumetric flow rate (Qi) of 
the effluent gas from each of the emission points.
    (3) Compute the equivalent P2O5 feed rate (P) 
using Equation BB-2:

[GRAPHIC] [TIFF OMITTED] TP07NO14.004

Where:

P = P2O5 feed rate, metric ton/hour (ton/
hour).
Mp = Total mass flow rate of phosphorus-bearing feed, 
metric ton/hour (ton/hour).
Rp = P2O5 content, decimal 
fraction.

    (i) Determine the mass flow rate (Mp) of the phosphorus-
bearing feed using the measurement system described in Sec.  63.625(a).
    (ii) Determine the P2O5 content 
(Rp) of the feed using, as appropriate, the following 
methods specified in the Book of Methods Used and Adopted By The 
Association of Florida Phosphate Chemists (Seventh Edition, 1991) where 
applicable:
    (A) Section IX, Methods of Analysis for Phosphate Rock, No. 1 
Preparation of Sample (incorporated by reference, see Sec.  63.14).
    (B) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus--P2O5 or 
Ca3(PO4)2, Method A--Volumetric Method 
(incorporated by reference, see Sec.  63.14).
    (C) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method B--Gravimetric 
Quimociac Method (incorporated by reference, see Sec.  63.14).
    (D) Section IX, Methods of Analysis for Phosphate Rock, No. 3 
Phosphorus-P2O5 or 
Ca3(PO4)2, Method C--Spectrophotometric Method 
(incorporated by reference, see Sec.  63.14).
    (E) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method A--Volumetric 
Method (incorporated by reference, see Sec.  63.14).
    (F) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus-P2O5, Method B--Gravimetric 
Quimociac Method (incorporated by reference, see Sec.  63.14).
    (G) Section XI, Methods of Analysis for Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and

[[Page 66583]]

Ammonium Phosphates, No. 3 Total Phosphorus-P2O5, 
Method C--Spectrophotometric Method (incorporated by reference, see 
Sec.  63.14).
    (g) For each granular triple superphosphate storage building, you 
must determine compliance with the applicable total fluorides or 
hydrogen fluoride standards specified in Tables 1, 1a, 2, and 2a to 
this subpart as specified in paragraphs (g)(1) through (7) of this 
section.
    (1) You must conduct performance tests only when the following 
quantities of product are being cured or stored in the facility:
    (i) Total granular triple superphosphate is at least 10 percent of 
the building capacity, and
    (ii) Fresh granular triple superphosphate is at least six percent 
of the total amount of granular triple superphosphate, or
    (iii) If the provision in paragraph (g)(1)(ii) of this section 
exceeds production capabilities for fresh granular triple 
superphosphate, the fresh granular triple superphosphate is equal to at 
least 5 days maximum production.
    (2) Compute the emission rate (E) of total fluorides or hydrogen 
fluoride for each run using Equation BB-3:
[GRAPHIC] [TIFF OMITTED] TP07NO14.005

Where:

E = Emission rate of total fluorides or hydrogen fluoride, gram/
hour/metric ton (pound/hour/ton) of equivalent 
P2O5 stored.
Ci = Concentration of total fluorides or hydrogen 
fluoride from emission point ``i,'' milligram/dry standard cubic 
meter (milligram/dry standard cubic feet).
Qi = Volumetric flow rate of effluent gas from emission 
point ``i,'' dry standard cubic meter/hour (dry standard cubic feet/
hour).
N = Number of emission points in the affected facility.
P = Equivalent P2O5 stored, metric tons 
(tons).
K = Conversion factor, 1000 milligram/gram (453,600 milligram/
pound).

    (3) You must use the test methods and procedures as specified in 
paragraphs (g)(3)(i) or (g)(3)(ii) of this section.
    (i) You must use Method 13A or 13B (40 CFR part 60, appendix A) to 
determine the total fluorides concentration (Ci) and the 
volumetric flow rate (Qi) of the effluent gas at each 
emission point. The sampling time for each run at each emission point 
must be at least 60 minutes. The sampling volume for each run at each 
emission point must be at least 0.85 dscm (30 dscf). If Method 13B is 
used, the fusion of the filtered material described in Section 7.3.1.2 
and the distillation of suitable aliquots of containers 1 and 2, 
described in section 7.3.3 and 7.3.4 in Method 13A, may be omitted.
    (ii) You must use Method 320 at 40 CFR part 63, appendix A, to 
determine the hydrogen fluoride concentration (Ci) at each 
emission point. The sampling time for each run must be at least 60 
minutes. You must use Method 2 at 40 CFR part 60, Appendix A-1 to 
determine the volumetric flow rate (Qi) of the effluent gas 
from each of the emission points.
    (4) Compute the equivalent P2O5 stored (P) 
using Equation BB-4:
[GRAPHIC] [TIFF OMITTED] TP07NO14.006

Where:

P = P2O5 stored (ton).
Mp = Amount of product in storage, metric ton (ton).
Rp = P2O5 content of product in 
storage, weight fraction.

    (5) Determine the amount of product (Mp) in storage 
using the measurement system described in Sec.  63.625(b) and (c).
    (6) Determine the P2O5 content 
(Rp) of the product stored using, as appropriate, the 
following methods specified in the Book of Methods Used and Adopted By 
The Association of Florida Phosphate Chemists, Seventh Edition 1991, 
where applicable:
    (i) Section XI, Methods of Analysis For Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus--P2O5, Method A--Volumetric 
Method (incorporated by reference, see Sec.  63.14).
    (ii) Section XI, Methods of Analysis For Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus--P2O5, Method B--Gravimetric 
Quimociac Method (incorporated by reference, see Sec.  63.14).
    (iii) Section XI, Methods of Analysis For Phosphoric Acid, 
Superphosphate, Triple Superphosphate, and Ammonium Phosphates, No. 3 
Total Phosphorus--P2O5, Method C--
Spectrophotometric Method (incorporated by reference, see Sec.  63.14), 
or,
    (7) Determine the P2O5 content 
(Rp) of the product stored using, as appropriate, the 
following methods specified in the Official Methods of Analysis of AOAC 
International, Sixteenth edition, 1995, where applicable:
    (i) AOAC Official Method 957.02 Phosphorus (Total) In Fertilizers, 
Preparation of Sample Solution, Sixteenth edition, 1995, (incorporated 
by reference, see Sec.  63.14).
    (ii) AOAC Official Method 929.01 Sampling of Solid Fertilizers, 
Sixteenth edition, 1995, (incorporated by reference, see Sec.  63.14).
    (iii) AOAC Official Method 929.02 Preparation of Fertilizer Sample, 
Sixteenth edition, (incorporated by reference, see Sec.  63.14).
    (iv) AOAC Official Method 978.01 Phosphorus (Total) in Fertilizers, 
Automated Method, Sixteenth edition, 1995 (incorporated by reference, 
see Sec.  63.14).
    (v) AOAC Official Method 969.02 Phosphorus (Total) in Fertilizers, 
Alkalimetric Quinolinium Molybdophosphate Method, Sixteenth edition, 
1995 (incorporated by reference, see Sec.  63.14).
    (vi) AOAC Official Method 962.02 Phosphorus (Total) in Fertilizers, 
Gravimetric Quinolinium Molybdophosphate Method, Sixteenth edition, 
1995 (incorporated by reference, see Sec.  63.14).
    (vii) AOAC Official Method 958.01 Phosphorus (Total) in 
Fertilizers, Spectrophotometric Molybdovanadophosphate Method, 
Sixteenth edition, 1995 (incorporated by reference, see Sec.  63.14).
    (h) If you use a CMS, you must conduct a performance evaluation, as 
specified in Sec.  63.8(e), in accordance with your site-specific 
monitoring plan in Sec.  63.628(c). For fabric filters, you must 
conduct a performance evaluation of the bag leak detection system 
consistent with the guidance provided in Office Of Air Quality Planning 
And Standards (OAQPS), Fabric Filter Bag Leak Detection Guidance, EPA-
454/R-98-015, September 1997 (incorporated by reference, see Sec.  
63.14). You must record the sensitivity of the bag leak detection 
system to detecting changes in particulate matter emissions, range,

[[Page 66584]]

averaging period, and alarm set points during the performance test.


Sec.  63.627  Notification, recordkeeping, and reporting requirements.

    (a) You must comply with the notification requirements specified in 
Sec.  63.9. You must also notify the Administrator each time that the 
operating limits change based on data collected during the most recent 
performance test. When a source is retested and the performance test 
results are submitted to the Administrator pursuant to paragraph (b)(1) 
of this section, Sec.  63.7(g)(1), or Sec.  63.10(d)(2), you must 
indicate whether the operating range will be based on the new 
performance test or the previously established range. Upon 
establishment of a new operating range, you must thereafter operate 
under the new range. If the Administrator determines that you did not 
conduct the compliance test in accordance with the applicable 
requirements or that the ranges established during the performance test 
do not represent normal operations, you must conduct a new performance 
test and establish new operating ranges.
    (b) You must comply with the reporting and recordkeeping 
requirements in Sec.  63.10 as specified in paragraphs (b)(1) through 
(5) of this section.
    (1) You must comply with the general recordkeeping requirements in 
Sec.  63.10(b)(1); and
    (2) As required by Sec.  63.10(d), you must report the results of 
the initial and subsequent performance tests as part of the 
notification of compliance status required in Sec.  63.9(h). You must 
verify in the performance test reports that the operating limits for 
each process have not changed or provide documentation of revised 
operating limits established according to Sec.  63.625, as applicable. 
In the notification of compliance status, you must also:
    (i) Certify to the Administrator that you have not shipped fresh 
granular triple superphosphate from an affected facility.
    (ii) Certify to the Administrator annually that you have complied 
with the evaporative cooling tower requirements specified in Sec.  
63.622(c).
    (iii) Submit analyses and supporting documentation demonstrating 
conformance with the Office Of Air Quality Planning And Standards 
(OAQPS), Fabric Filter Bag Leak Detection Guidance, EPA-454/R-98-015, 
September 1997 (incorporated by reference, see Sec.  63.14) and 
specifications for bag leak detection systems as part of the 
notification of compliance status report.
    (iv) If you elect to demonstrate compliance by following the 
procedures in Sec.  63.625(d)(1)(ii)(B), certify to the Administrator 
annually that the control devices and processes have not been modified 
since the date of the performance test from which you obtained the data 
used to establish the allowable ranges.
    (3) As required by Sec.  63.10(e)(1), you must submit an excess 
emissions report for any exceedance of an emission or operating 
parameter limit if the total duration of the exceedances for the 
reporting period is 1 percent of the total operating time for the 
reporting period or greater. The report must contain the information 
specified in Sec.  63.10 and paragraph (b)(4) of this section. When 
exceedances of an emission limit or operating parameter have not 
occurred, you must include such information in the report. You must 
submit the report semiannually and the report must be delivered or 
postmarked by the 30th day following the end of the calendar half. If 
exceedances are reported, you must submit the excess emissions report 
quarterly until a request to reduce reporting frequency is approved as 
described in Sec.  63.10(e)(3).
    (4) In the event that an affected unit fails to meet an applicable 
standard, record and report the following information for each failure:
    (i) The date, time and duration of the failure.
    (ii) A list of the affected sources or equipment for which a 
failure occurred.
    (iii) An estimate of the volume of each regulated pollutant emitted 
over any emission limit.
    (iv) A description of the method used to estimate the emissions.
    (v) A record of actions taken to minimize emissions in accordance 
with Sec.  63.628(b), and any corrective actions taken to return the 
affected unit to its normal or usual manner of operation.
    (5) You must submit a summary report containing the information 
specified in Sec.  63.10(e)(3)(vi). You must submit the summary report 
semiannually and the report must be delivered or postmarked by the 30th 
day following the end of the calendar half.
    (c) Your records must be in a form suitable and readily available 
for expeditious review. You must keep each record for 5 years following 
the date of each recorded action. You must keep each record on site, or 
accessible from a central location by computer or other means that 
instantly provide access at the site, for at least 2 years after the 
date of each recorded action. You may keep the records off site for the 
remaining 3 years.
    (d) In computing averages to determine compliance with this 
subpart, you must exclude the monitoring data specified in paragraphs 
(d)(1) through (3) of this section.
    (1) Periods of non-operation of the process unit;
    (2) Periods of no flow to a control device; and
    (3) Any monitoring data recorded during continuous parameter 
monitoring system (CPMS) breakdowns, out-of-control periods, repairs, 
maintenance periods, instrument adjustments or checks to maintain 
precision and accuracy, calibration checks, and zero (low-level), mid-
level (if applicable), and high-level adjustments.
    (e) Within 60 days after the date of completing each performance 
test (as defined in Sec.  63.2), you must submit the results of the 
performance tests, including any associated fuel analyses, required by 
this subpart according to the methods specified in paragraphs (e)(1) or 
(2) of this section.
    (1) For data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT Web site 
(https://www.epa.gov/ttn/chief/ert/), you must submit the 
results of the performance test to the Compliance and Emissions Data 
Reporting Interface (CEDRI) that is accessed through the EPA's Central 
Data Exchange (CDX) (https://cdx.epa.gov/epa_home.asp), unless the 
Administrator approves another approach. Performance test data must be 
submitted in a file format generated through the use of the EPA's ERT. 
Owners or operators, who claim that some of the information being 
submitted for performance tests is confidential business information 
(CBI), must submit a complete file generated through the use of the 
EPA's ERT, including information claimed to be CBI, on a compact disk, 
flash drive, or other commonly used electronic storage media to the 
EPA. The electronic media must be clearly marked as CBI and mailed to 
U.S. EPA/OAQPS/CORE CBI Office, Attention: WebFIRE Administrator, MD 
C404-02, 4930 Old Page Rd., Durham, NC 27703. The same ERT file with 
the CBI omitted must be submitted to the EPA via CDX as described 
earlier in this paragraph.
    (2) For any performance test conducted using test methods that are 
not supported by the EPA's ERT as listed on the EPA's ERT Web site, the 
owner or operator shall submit the results of the performance test to 
the Administrator at the appropriate address listed in Sec.  63.13.

[[Page 66585]]

Sec.  63.628  General requirements and applicability of part 63 general 
provisions.

    (a) You must comply with the general provisions in subpart A of 
this part as specified in appendix A to this subpart.
    (b) At all times, you must operate and maintain any affected 
source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions. The general duty 
to minimize emissions does not require you to make any further efforts 
to reduce emissions if levels required by this standard have been 
achieved. Determination by the Administrator of whether a source is 
operating in compliance with operation and maintenance requirements 
will be based on information available to the Administrator that may 
include, but is not limited to, monitoring results, review of operation 
and maintenance procedures, review of operation and maintenance 
records, and inspection of the source.
    (c) For each CMS used to demonstrate compliance with any applicable 
emission limit, you must develop, and submit to the Administrator for 
approval upon request, a site-specific monitoring plan according to the 
requirements specified in paragraphs (c)(1) through (3) of this 
section. You must submit the site-specific monitoring plan, if 
requested by the Administrator, at least 60 days before the initial 
performance evaluation of the CMS. The requirements of this paragraph 
also apply if a petition is made to the Administrator for alternative 
monitoring parameters under Sec.  63.8(f).
    (1) You must include the information specified in paragraphs 
(c)(1)(i) through (vi) of this section in the site-specific monitoring 
plan.
    (i) Location of the CMS sampling probe or other interface. You must 
include a justification demonstrating that the sampling probe or other 
interface is at a measurement location relative to each affected 
process unit such that the measurement is representative of control of 
the exhaust emissions (e.g., on or downstream of the last control 
device).
    (ii) Performance and equipment specifications for the sample 
interface, the pollutant concentration or parametric signal analyzer, 
and the data collection and reduction systems.
    (iii) Performance evaluation procedures and acceptance criteria 
(e.g., calibrations).
    (iv) Ongoing operation and maintenance procedures in accordance 
with the general requirements of Sec.  63.8(c)(1)(ii), (c)(3), 
(c)(4)(ii), and Table 4 to this subpart.
    (v) Ongoing data quality assurance procedures in accordance with 
the general requirements of Sec.  63.8(d)(1) and (2) and Table 5 to 
this subpart.
    (vi) Ongoing recordkeeping and reporting procedures in accordance 
with the general requirements of Sec. Sec.  63.10(c), 63.10 (e)(1), and 
63.10(e)(2)(i).
    (2) You must include a schedule for conducting initial and 
subsequent performance evaluations in the site-specific monitoring 
plan.
    (3) You must keep the site-specific monitoring plan on site for the 
life of the affected source or until the affected source is no longer 
subject to the provisions of this part, to be made available for 
inspection, upon request, by the Administrator. If you revise the site-
specific monitoring plan, you must keep previous (i.e., superseded) 
versions of the plan on site to be made available for inspection, upon 
request, by the Administrator, for a period of 5 years after each 
revision to the plan. You must include the program of corrective action 
required under Sec.  63.8(d)(2) in the plan.
    (d) For each bag leak detection system installed to comply with the 
requirements specified in Sec.  63.625(e), you must include the 
information specified in paragraphs (d)(1) and (2) of this section in 
the site-specific monitoring plan specified in paragraph (c) of this 
section.
    (1) Performance evaluation procedures and acceptance criteria 
(e.g., calibrations), including how the alarm set-point will be 
established.
    (2) A corrective action plan describing corrective actions to be 
taken and the timing of those actions when the bag leak detection alarm 
sounds. Corrective actions may include, but are not limited to, the 
actions specified in paragraphs (d)(2)(i) through (vi) of this section.
    (i) Inspecting the fabric filter for air leaks, torn or broken bags 
or filter media, or any other conditions that may cause an increase in 
regulated material emissions.
    (ii) Sealing off defective bags or filter media.
    (iii) Replacing defective bags or filter media or otherwise 
repairing the control device.
    (iv) Sealing off a defective fabric filter compartment.
    (v) Cleaning the bag leak detection system probe or otherwise 
repairing the bag leak detection system.
    (vi) Shutting down the process controlled by the fabric filter.


Sec.  63.629  Miscellaneous requirements.

    The Administrator retains the authority to approve site-specific 
test plans for uncontrolled granular triple superphosphate storage 
buildings developed pursuant to Sec.  63.7(c)(2)(i).


Sec.  63.630  [Reserved]


Sec.  63.631  Exemption from new source performance standards.

    Any affected source subject to the provisions of this subpart is 
exempted from any otherwise applicable new source performance standard 
contained in 40 CFR part 60, subpart V, subpart W, or subpart X. To be 
exempt, a source must have a current operating permit pursuant to title 
V of the Clean Air Act and the source must be in compliance with all 
requirements of this subpart. For each affected source, this exemption 
is effective upon the date that you demonstrate to the Administrator 
that the requirements of Sec. Sec.  63.625 and 63.626 have been met.


Sec.  63.632  Implementation and enforcement.

    (a) This subpart is implemented and enforced by the U.S. EPA, or a 
delegated authority such as the applicable state, local, or Tribal 
agency. If the U.S. EPA Administrator has delegated authority to a 
state, local, or Tribal agency, then that agency, in addition to the 
U.S. EPA, has the authority to implement and enforce this subpart. 
Contact the applicable U.S. EPA Regional Office to find out if 
implementation and enforcement of this subpart is delegated to a state, 
local, or Tribal agency.
    (b) The authorities specified in paragraphs (b)(1) through (5) of 
this section are retained by the Administrator of U.S. EPA and cannot 
be delegated to State, local, or Tribal agencies.
    (1) Approval of alternatives to the requirements in Sec. Sec.  
63.620, 63.622, 63.625, 63.629, and 63.631.
    (2) Approval of requests under Sec. Sec.  63.7(e)(2)(ii) and 
63.7(f) for alternative requirements or major changes to the test 
methods specified in this subpart, as defined in Sec.  63.90.
    (3) Approval of requests under Sec.  63.8(f) for alternative 
requirements or major changes to the monitoring requirements specified 
in this subpart, as defined in Sec.  63.90.
    (4) Waiver or approval of requests under Sec.  63.10(f) for 
alternative requirements or major changes to the recordkeeping and 
reporting requirements specified in this subpart, as defined in Sec.  
63.90.
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

[[Page 66586]]



   Table 1 to Subpart BB of Part 63--Existing Source Phase 1 Emission
                             Limits \a\ \b\
------------------------------------------------------------------------
                               You must meet the emission limits for the
  For the following existing           specified pollutant . . .
        sources . . .         ------------------------------------------
                               Total fluorides      Hydrogen fluoride
------------------------------------------------------------------------
Process Line that Produces a   0.060 lb/ton of
 Reaction Product Of Ammonia    equivalent
 And Phosphoric Acid (e.g.,     P2O5 feed.
 Diammonium and/or
 Monoammonium Phosphate
 Process Line).
Granular Triple                0.150 lb/ton of
 Superphosphate Process Line.   equivalent
                                P2O5 feed.
GTSP storage building........  5.0x10-4 lb/hr/
                                ton of
                                equivalent
                                P2O5 stored.
------------------------------------------------------------------------
\a\ The phase 1 existing source compliance date is June 10, 2002.
\b\ During periods of startup and shutdown, for emission limits stated
  in terms of pounds of pollutant per ton of feed, you are subject to
  the work practice standards specified in Sec.   63.622(d).


   Table 1a to Subpart BB of Part 63--Existing Source Phase 2 Emission
                             Limits \a\ \b\
------------------------------------------------------------------------
                                   You must meet the emission limits for
   For the following existing          the specified pollutant . . .
          sources . . .          ---------------------------------------
                                    Total fluorides    Hydrogen fluoride
------------------------------------------------------------------------
Process Line that Produces a      ..................  0.060 lb/ton of
 Reaction Product Of Ammonia And                       equivalent P2O5
 Phosphoric Acid (e.g.,                                feed.
 Diammonium and/or Monoammonium
 Phosphate Process Line).
Granular Triple Superphosphate    ..................  0.150 lb/ton of
 Process Line.                                         equivalent P2O5
                                                       feed.
GTSP storage building...........  ..................  5.0x10-4 lb/hr/ton
                                                       of equivalent
                                                       P2O5 stored.
------------------------------------------------------------------------
\a\ The phase 2 existing source compliance date is [date one year after
  the date of publication of the final rule in the Federal Register] or
  immediately upon startup, whichever is later.
\b\ During periods of startup and shutdown, for emission limits stated
  in terms of pounds of pollutant per ton of feed, you are subject to
  the work practice standards specified in Sec.   63.622(d).


Table 2 to Subpart BB of Part 63--New Source Phase 1 Emission Limits \a\
                                   \b\
------------------------------------------------------------------------
                                   You must meet the emission limits for
   For the following existing          the specified pollutant . . .
          sources . . .          ---------------------------------------
                                    Total fluorides    Hydrogen fluoride
------------------------------------------------------------------------
Process Line that Produces a      0.0580 lb/ton of    ..................
 Reaction Product Of Ammonia And   equivalent P2O5
 Phosphoric Acid (e.g.,            feed.
 Diammonium and/or Monoammonium
 Phosphate Process Line).
Granular Triple Superphosphate    0.1230 lb/ton of    ..................
 Process Line.                     equivalent P2O5
                                   feed.
GTSP storage building...........  5.0x10-4 lb/hr/ton  ..................
                                   of equivalent
                                   P2O5 stored.
------------------------------------------------------------------------
\a\ The phase 1 new source compliance dates are based on date of
  construction or reconstruction as specified in Sec.   63.622(a).
\b\ During periods of startup and shutdown, for emission limits stated
  in terms of pounds of pollutant per ton of feed, you are subject to
  the work practice standards specified in Sec.   63.622(d).


  Table 2a to Subpart BB of Part 63--New Source Phase 2 Emission Limits
                                 \a\ \b\
------------------------------------------------------------------------
                               You must meet the emission limits for the
                                       specified  pollutant . . .
For the following new sources ------------------------------------------
            . . .                                            Hydrogen
                                    Total fluorides          fluoride
------------------------------------------------------------------------
Process Line That Produces a   ........................  0.0580 lb/ton
 Reaction Product of Ammonia                              of equivalent
 and Phosphoric Acid (e.g.,                               P2O5 feed
 Diammonium and/or
 Monoammonium Phosphate
 Process Line).
Granular Triple                ........................  0.1230 lb/ton
 Superphosphate Process Line.                             of equivalent
                                                          P2O5 feed
GTSP storage building........  ........................  5.0 x 10-4 lb/
                                                          hr/ton of
                                                          equivalent
                                                          P2O5 stored
------------------------------------------------------------------------
\a\ The phase 2 new source compliance dates are based on date of
  construction or reconstruction as specified in Sec.   63.622(a).
\b\ During periods of startup and shutdown, for emission limits stated
  in terms of pounds of pollutant per ton of feed, you are subject to
  the work practice standards specified in Sec.   63.622(d).


[[Page 66587]]


                   Table 3 to Subpart BB of Part 63--Monitoring Equipment Operating Parameters
----------------------------------------------------------------------------------------------------------------
                                                                 And you must monitor .
            You must . . .                     If . . .                   . .                   And . . .
----------------------------------------------------------------------------------------------------------------
                     All Absorbers (Wet Scrubbers): Choose one of the following two options
----------------------------------------------------------------------------------------------------------------
Install a continuous parameter         You choose to monitor    Influent liquid flow...  .......................
 monitoring system (CPMS) for liquid    only the influent
 flow at the inlet of the absorber.     liquid flow, rather
                                        than the liquid-to-gas
                                        ratio.
Install CPMS for liquid and gas flow   You choose to monitor    Liquid-to-gas ratio as   You must measure the
 at the inlet of the absorber.          the liquid-to-gas        determined by dividing   gas stream by:
                                        ratio, rather than       the influent liquid     Measuring the gas
                                        only the influent        flow rate by the inlet   stream flow at the
                                        liquid flow, and you     gas flow rate.The        absorber inlet;
                                        want the ability to      units of measure must   or
                                        lower liquid flow with   be consistent with      Using the design blower
                                        changes in gas flow.     those used to            capacity, with
                                                                 calculate this ratio     appropriate
                                                                 during the performance   adjustments for
                                                                 test.                    pressure drop.
----------------------------------------------------------------------------------------------------------------
               Absorbers (Wet Scrubbers): You must also choose one of the following three options
----------------------------------------------------------------------------------------------------------------
Install CPMS for pressure at the gas   You choose to monitor    Pressure drop through    You may measure the
 stream inlet and outlet of the         pressure drop through    the absorber.            pressure of the inlet
 absorber.                              the absorber, and your                            gas using amperage on
                                        pressure drop through                             the blower if a
                                        the absorber is                                   correlation between
                                        greater than 5 inches                             pressure and amperage
                                        of water.                                         is established.
Install CPMS for temperature at the    You choose to monitor    Exit gas temperature of  .......................
 absorber gas stream outlet and         outlet temperature and   the absorber and inlet
 pressure at the liquid inlet of the    inlet pressure of the    liquid pressure of the
 adsorber.                              liquid.                  absorber.
Install CPMS for temperature at the    You choose to monitor    Exit gas temperature of  .......................
 absorber gas stream outlet and         temperature              the absorber and inlet
 absorber gas stream inlet.             differential across      gas temperature of the
                                        the absorber.            absorber.
----------------------------------------------------------------------------------------------------------------


 Table 4 to Subpart BB of Part 63--Operating Parameters, Operating Limits and Data Monitoring, Recordkeeping and
                                             Compliance Frequencies
----------------------------------------------------------------------------------------------------------------
                                  You must establish   And you must monitor, record, and demonstrate continuous
                                     the following            compliance using these minimum frequencies
   For the operating parameter      operating limit  -----------------------------------------------------------
 applicable to you, as specified      during your
        in Table 3 . . .          performance test .                                            Data averaging
                                          . .          Data measurement     Data recording        period for
                                                                                                  compliance
----------------------------------------------------------------------------------------------------------------
                                            Absorbers (Wet Scrubbers)
----------------------------------------------------------------------------------------------------------------
Influent liquid flow............  Minimum inlet       Continuous........  Every 15 minutes..  Daily.
                                   liquid flow.
Influent liquid flow rate and     Minimum influent    Continuous........  Every 15 minutes..  Daily.
 gas stream flow rate.             liquid-to-gas
                                   ratio.
Pressure drop...................  Pressure drop       Continuous........  Every 15 minutes..  Daily.
                                   range.
Exit gas temperature............  Maximum exit gas    Continuous........  Every 15 minutes..  Daily.
                                   temperature.
Inlet gas temperature...........  Minimum             Continuous........  Every 15 minutes..  Daily.
                                   temperature
                                   difference
                                   between inlet and
                                   exit gas.
Inlet liquid pressure...........  Minimum Inlet       Continuous........  Every 15 minutes..  Daily.
                                   liquid pressure.
----------------------------------------------------------------------------------------------------------------


    Table 5 to Subpart BB of Part 63--Calibration and Quality Control
     Requirements for Continuous Parameter Monitoring Systems (CPMS)
------------------------------------------------------------------------
                                  Your accuracy     And your calibration
 If you monitor this parameter   requirements are   requirements are . .
             . . .                    . . .                  .
------------------------------------------------------------------------
Temperature...................   1     Performance
                                 percent over the   evaluation annually
                                 normal range of    and following any
                                 temperature        period of more than
                                 measured or 2.8    24 hours throughout
                                 degrees Celsius    which the
                                 (5 degrees         temperature exceeded
                                 Fahrenheit),       the maximum rated
                                 whichever is       temperature of the
                                 greater, for non-  sensor, or the data
                                 cryogenic          recorder was off
                                 temperature        scale. Visual
                                 ranges.            inspections and
                                                    checks of CPMS
                                                    operation every 3
                                                    months, unless the
                                                    CPMS has a redundant
                                                    temperature sensor.
                                                   Selection of a
                                                    representative
                                                    measurement
                                                    location.

[[Page 66588]]

 
Flow Rate.....................   5     Performance
                                 percent over the   evaluation annually
                                 normal range of    and following any
                                 flow measured or   period of more than
                                 1.9 liters per     24 hours throughout
                                 minute (0.5        which the flow rate
                                 gallons per        exceeded the maximum
                                 minute),           rated flow rate of
                                 whichever is       the sensor, or the
                                 greater, for       data recorder was
                                 liquid flow rate.  off scale. Checks of
                                                    all mechanical
                                                    connections for
                                                    leakage monthly.
                                                    Visual inspections
                                                    and checks of CPMS
                                                    operation every 3
                                                    months, unless the
                                                    CPMS has a redundant
                                                    flow sensor.
                                                   Selection of a
                                                    representative
                                                    measurement location
                                                    where swirling flow
                                                    or abnormal velocity
                                                    distributions due to
                                                    upstream and
                                                    downstream
                                                    disturbances at the
                                                    point of measurement
                                                    are minimized.
                                 5
                                 percent over the
                                 normal range of
                                 flow measured or
                                 28 liters per
                                 minute (10 cubic
                                 feet per
                                 minute),
                                 whichever is
                                 greater, for gas
                                 flow rate.
                                 5
                                 percent over the
                                 normal range
                                 measured for
                                 mass flow rate.
Pressure......................   5     Checks for
                                 percent over the   obstructions (e.g.,
                                 normal range       pressure tap
                                 measured or 0.12   pluggage) at least
                                 kilopascals (0.5   once each process
                                 inches of water    operating day.
                                 column),          Performance
                                 whichever is       evaluation annually
                                 greater.           and following any
                                                    period of more than
                                                    24 hours throughout
                                                    which the pressure
                                                    exceeded the maximum
                                                    rated pressure of
                                                    the sensor, or the
                                                    data recorder was
                                                    off scale.
                                                   Checks of all
                                                    mechanical
                                                    connections for
                                                    leakage monthly.
                                                   Visual inspection of
                                                    all components for
                                                    integrity, oxidation
                                                    and galvanic
                                                    corrosion every 3
                                                    months, unless the
                                                    CPMS has a redundant
                                                    pressure sensor.
                                                   Selection of a
                                                    representative
                                                    measurement location
                                                    that minimizes or
                                                    eliminates pulsating
                                                    pressure, vibration,
                                                    and internal and
                                                    external corrosion.
------------------------------------------------------------------------


 Appendix A to Subpart BB of Part 63--Applicability of General Provisions (40 CFR Part 63, Subpart A) to Subpart
                                                       BB
----------------------------------------------------------------------------------------------------------------
          40 CFR citation                    Requirement           Applies to subpart BB          Comment
----------------------------------------------------------------------------------------------------------------
Sec.   63.1(a)(1) through (4)......  General Applicability......  Yes...................  None.
Sec.   63.1(a)(5)..................  ...........................  No....................  [Reserved].
Sec.   63.1(a)(6)..................  Contact information........  Yes...................  None.
Sec.   63.1(a)(7) through (9)......  ...........................  No....................  [Reserved].
Sec.   63.1(a)(10) through (12)....  Time periods...............  Yes...................  None.
Sec.   63.1(b).....................  Initial Applicability        Yes...................  None.
                                      Determination.
Sec.   63.1(c)(1)..................  Applicability After          Yes...................  None.
                                      Standard Established.
Sec.   63.1(c)(2)..................  Permits....................  Yes...................  Some plants may be
                                                                                           area sources.
Sec.   63.1(c)(3) through (4)......  ...........................  No....................  [Reserved].
Sec.   63.1(c)(5)..................  Area to Major source change  Yes...................  None.
Sec.   63.1(d).....................  ...........................  No....................  [Reserved].
Sec.   63.1(e).....................  Applicability of Permit      Yes...................  None.
                                      Program.
Sec.   63.2........................  Definitions................  Yes...................  Additional definitions
                                                                                           in Sec.   63.621.
Sec.   63.3........................  Units and Abbreviations....  Yes...................  None.
Sec.   63.4(a)(1) and (2)..........  Prohibited Activities......  Yes...................  None.
Sec.   63.4(a)(3) through (5)......  ...........................  No....................  [Reserved].
Sec.   63.4(b) and (c).............  CircumventionFragmentation.  Yes...................  None.
Sec.   63.5(a).....................  ConstructionReconstruction   Yes...................  None.
                                      Applicability.
Sec.   63.5(b)(1)..................  Existing, New,               Yes...................  None.
                                      Reconstructed Sources
                                      Requirements.
Sec.   63.5(b)(2)..................  ...........................  No....................  [Reserved].
Sec.   63.5(b)(3), (4), and (6)....  ConstructionReconstruction   Yes...................  None.
                                      approval and notification.
Sec.   63.5(b)(5)..................  ...........................  No....................  [Reserved]
Sec.   63.5(c).....................  ...........................  No....................  [Reserved].
Sec.   63.5(d).....................  Application for Approval of  Yes...................  None.
                                      ConstructionReconstruction.
Sec.   63.5(e).....................  Approval of                  Yes...................  None.
                                      ConstructionReconstruction.
Sec.   63.5(f).....................  Approval of                  Yes...................  None.
                                      ConstructionReconstruction
                                      Based on State Review.
Sec.   63.6(a).....................  Compliance with Standards    Yes...................  None.
                                      and Maintenance
                                      Applicability.
Sec.   63.6(b)(1) through (5)......  New and Reconstructed        Yes...................  See also Sec.
                                      Sources Dates.                                       63.622.
Sec.   63.6(b)(6)..................  ...........................  No....................  [Reserved].
Sec.   63.6(b)(7)..................  Area to major source change  Yes...................  None.
Sec.   63.6(c)(1)and (2)...........  Existing Sources Dates.....  Yes...................  Sec.   63.622
                                                                                           specifies dates.
Sec.   63.6(c)(3) and (4)..........  ...........................  No....................  [Reserved].

[[Page 66589]]

 
Sec.   63.6(c)(5)..................  Area to major source change  Yes...................  None.
Sec.   63.6(d).....................  ...........................  No....................  [Reserved].
Sec.   63.6(e)(1)(i) and (ii)......  Operation & Maintenance      No....................  See Sec.   63.628(b)
                                      Requirements.                                        for general duty
                                                                                           requirement
Sec.   63.6(e)(iii)................  ...........................  Yes...................  None.
Sec.   63.6(e)(2)..................  ...........................  No....................  [Reserved]
Sec.   63.6(e)(3)..................  Startup, Shutdown, and       No....................  None.
                                      Malfunction Plan.
Sec.   63.6(f).....................  Compliance with Emission     No....................  See general duty at
                                      Standards.                                           Sec.   63.628(b)
Sec.   63.6(g).....................  Alternative Standard.......  Yes...................  None.
Sec.   63.6(h).....................  Compliance with OpacityVE    No....................  Subpart BB does not
                                      Standards.                                           include VEopacity
                                                                                           standards.
Sec.   63.6(i)(1) through (14).....  Extension of Compliance....  Yes...................  None.
Sec.   63.6(i)(15).................  ...........................  No....................  [Reserved].
Sec.   63.6(i)(16).................  ...........................  Yes...................  None.
Sec.   63.6(j).....................  Exemption from Compliance..  Yes...................  None.
Sec.   63.7(a).....................  Performance Test             Yes...................  None.
                                      Requirements Applicability.
Sec.   63.7(b).....................  Notification...............  Yes...................  None.
Sec.   63.7(c).....................  Quality AssuranceTest Plan.  Yes...................  None.
Sec.   63.7(d).....................  Testing Facilities.........  Yes...................  None.
Sec.   63.7(e)(1)..................  Conduct of Tests; startup,   No....................  Sec.   63.626
                                      shutdown and malfunction                             specifies additional
                                      provisions.                                          requirements.
Sec.   63.7(e)(2) through (4)......  Conduct of Tests...........  Yes...................  Sec.   63.626
                                                                                           specifies additional
                                                                                           requirements.
Sec.   63.7(f).....................  Alternative Test Method....  Yes...................  None.
Sec.   63.7(g).....................  Data Analysis..............  Yes...................  None.
Sec.   63.7(h).....................  Waiver of Tests............  Yes...................  None.
Sec.   63.8(a).....................  Monitoring Requirements      Yes...................  Non.
                                      Applicability.
Sec.   63.8(b).....................  Conduct of Monitoring......  Yes...................  None.
Sec.   63.8(c)(1)(i)...............  General duty to minimize     No....................  See Sec.   63.628(b)
                                      emissions and CMS                                    for general duty
                                      operation.                                           requirement
Sec.   63.8(c)(1)(ii)..............  ...........................  Yes...................  None.
Sec.   63.8(c)(1)(iii).............  Requirement to develop SSM   No....................  None.
                                      Plan for CMS.
Sec.   63.8(c)(2) through (4)......  CMS OperationMaintenance...  Yes...................  None.
Sec.   63.8(c)(5)..................  COMS Operation.............  No....................  Subpart BB does not
                                                                                           require COMS
Sec.   63.8(c)(6) through (8)......  CMS requirements...........  Yes...................  None.
Sec.   63.8(d)(1) and (2)..........  Quality Control............  Yes...................  None.
Sec.   63.8(d)(3)..................  Written procedure for CMS..  No....................  See Sec.   63.628(d)
                                                                                           for requirement
Sec.   63.8(e).....................  CMS Performance Evaluation.  Yes...................  None.
Sec.   63.8(f)(1) through (5)......  Alternative Monitoring       Yes...................  None.
                                      Method.
Sec.   63.8(f)(6)..................  Alternative to RATA Test...  No....................  Subpart BB does not
                                                                                           require CEMS.
Sec.   63.8(g)(1)..................  Data Reduction.............  Yes...................  None.
Sec.   63.8(g)(2)..................  ...........................  No....................  Subpart BB does not
                                                                                           require COMS or CEMS.
Sec.   63.8(g)(3) through (5)......  ...........................  Yes...................  None.
Sec.   63.9(a).....................  Notification Requirements    Yes...................  None.
                                      Applicability.
Sec.   63.9(b).....................  Initial Notifications......  Yes...................  None.
Sec.   63.9(c).....................  Request for Compliance       Yes...................  None.
                                      Extension.
Sec.   63.9(d).....................  New Source Notification for  Yes...................  None.
                                      Special Compliance
                                      Requirements.
Sec.   63.9(e).....................  Notification of Performance  Yes...................  None.
                                      Test.
Sec.   63.9(f).....................  Notification of VEOpacity    No....................  Subpart BB does not
                                      Test.                                                include VEopacity
                                                                                           standards.
Sec.   63.9(g).....................  Additional CMS               Yes...................  None.
                                      Notifications.
Sec.   63.9(h)(1) through (3)......  Notification of Compliance   Yes...................  None.
                                      Status.
Sec.   63.9(h)(4)..................  ...........................  No....................  [Reserved].
Sec.   63.9(h)(5) and (6)..........  ...........................  Yes...................  None.
Sec.   63.9(i).....................  Adjustment of Deadlines....  Yes...................  None.
Sec.   63.9(j).....................  Change in Previous           Yes...................  None.
                                      Information.
Sec.   63.10(a)....................  RecordkeepingReporting-      Yes...................  None.
                                      Applicability.
Sec.   63.10(b)(1).................  General Recordkeeping        Yes...................  None.
                                      Requirements.
Sec.   63.10(b)(2)(i)..............  Startup or shutdown          No....................  None.
                                      duration.
Sec.   63.10(b)(2)(ii).............  Malfunction................  No....................  See Sec.   63.627 for
                                                                                           recordkeeping and
                                                                                           reporting
                                                                                           requirement.

[[Page 66590]]

 
Sec.   63.10(b)(2)(iii)............  Maintenance records........  Yes...................  None.
Sec.   63.10(b)(2)(iv) and (v).....  Startup, shutdown,           No....................  None.
                                      malfunction actions.
Sec.   63.10(b)(2)(vi) through       General Recordkeeping        Yes...................  None.
 (xiv).                               Requirements.
Sec.   63.10(b)(3).................  General Recordkeeping        Yes...................  None.
                                      Requirements.
Sec.   63.10(c)(1).................  Additional CMS               Yes...................  None.
                                      Recordkeeping.
Sec.   63.10(c)(2) through (4).....  ...........................  No....................  [Reserved].
Sec.   63.10(c)(5).................  ...........................  Yes...................  None.
Sec.   63.10(c)(6).................  ...........................  Yes...................  None.
Sec.   63.10(c)(7) and (8).........  ...........................  Yes...................  None.
Sec.   63.10(c)(9).................  ...........................  No....................  [Reserved].
Sec.   63.10(c)(10) through (13)...  ...........................  Yes...................  None.
Sec.   63.10(c)(14)................  ...........................  Yes...................  None.
Sec.   63.10(c)(15)................  Startup Shutdown             No....................  None.
                                      Malfunction Plan
                                      Provisions.
Sec.   63.10(d)(1).................  General Reporting            Yes...................  None.
                                      Requirements.
Sec.   63.10(d)(2).................  Performance Test Results...  Yes...................  None.
Sec.   63.10(d)(3).................  Opacity or VE Observations.  No....................  Subpart BB does not
                                                                                           include VEopacity
                                                                                           standards.
Sec.   63.10(d)(4).................  Progress Reports...........  Yes...................  None.
Sec.   63.10(d)(5).................  Startup, Shutdown, and       No....................  See Sec.   63.627 for
                                      Malfunction Reports.                                 reporting of excess
                                                                                           emissions.
Sec.   63.10(e)(1) and (2).........  Additional CMS Reports.....  Yes...................  None.
Sec.   63.10(e)(3).................  Excess EmissionsCMS          Yes...................  None.
                                      Performance Reports.
Sec.   63.10(e)(4).................  COMS Data Reports..........  No....................  Subpart BB does not
                                                                                           require COMS.
Sec.   63.10(f)....................  RecordkeepingReporting       Yes...................  None.
                                      Waiver.
Sec.   63.11.......................  Control Device and Work      Yes...................  None.
                                      Practice Requirements.
Sec.   63.12.......................  State Authority and          Yes...................  None.
                                      Delegations.
Sec.   63.13.......................  Addresses..................  Yes...................  None.
Sec.   63.14.......................  Incorporation by Reference.  Yes...................  None.
Sec.   63.15.......................  Information                  Yes...................  None.
                                      AvailabilityConfidentialit
                                      y.
Sec.   63.16.......................  Performance Track            No....................  Terminated.
                                      Provisions.
----------------------------------------------------------------------------------------------------------------


[FR Doc. 2014-25872 Filed 11-6-14; 8:45 am]
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