National Emission Standards for Hazardous Air Pollutants: Generic Maximum Achievable Control Technology Standards Residual Risk and Technology Review for Ethylene Production, 40386-40440 [2020-05898]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 85, Number 129 (Monday, July 6, 2020)]
[Rules and Regulations]
[Pages 40386-40440]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-05898]



[[Page 40385]]

Vol. 85

Monday,

No. 129

July 6, 2020

Part II





 Environmental Protection Agency





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40 CFR Part 63





National Emission Standards for Hazardous Air Pollutants: Generic 
Maximum Achievable Control Technology Standards Residual Risk and 
Technology Review for Ethylene Production; Final Rule

Federal Register / Vol. 85, No. 129 / Monday, July 6, 2020 / Rules 
and Regulations

[[Page 40386]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2017-0357; FRL-10006-87-OAR]
RIN 2060-AT02


National Emission Standards for Hazardous Air Pollutants: Generic 
Maximum Achievable Control Technology Standards Residual Risk and 
Technology Review for Ethylene Production

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action finalizes the residual risk and technology review 
(RTR) conducted for the Ethylene Production source category regulated 
under National Emission Standards for Hazardous Air Pollutants 
(NESHAP). In addition, the U.S. Environmental Protection Agency (EPA) 
is taking final action to correct and clarify regulatory provisions 
related to emissions during periods of startup, shutdown, and 
malfunction (SSM), including removing general exemptions for periods of 
SSM, adding work practice standards for periods of SSM where 
appropriate, and clarifying regulatory provisions for certain vent 
control bypasses. The EPA is also taking final action to revise 
requirements for heat exchange systems; add monitoring and operational 
requirements for flares; add provisions for electronic reporting of 
performance test results and other reports; and include other technical 
corrections to improve consistency and clarity. We estimate that these 
final amendments will reduce hazardous air pollutants (HAP) emissions 
from this source category by 29 tons per year (tpy) and reduce excess 
emissions of HAP from flares by an additional 1,430 tpy.

DATES: This final rule is effective on July 6, 2020. The incorporation 
by reference (IBR) of certain publications listed in the rule is 
approved by the Director of the Federal Register as of July 6, 2020.

ADDRESSES: The EPA has established a docket for this action under 
Docket ID No. EPA-HQ-OAR-2017-0357. All documents in the docket are 
listed on the https://www.regulations.gov/ website. Although listed, 
some information is not publicly available, e.g., Confidential Business 
Information (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 form. Publicly available docket materials are available either 
electronically through https://www.regulations.gov/, or in hard copy at 
the EPA Docket Center, WJC West Building, Room Number 3334, 1301 
Constitution Ave. NW, Washington, DC. The Public Reading Room hours of 
operation are 8:30 a.m. to 4:30 p.m., Eastern Standard Time (EST), 
Monday through Friday. 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.

FOR FURTHER INFORMATION CONTACT: For questions about this final action, 
contact Mr. Andrew Bouchard, Sector Policies and Programs Division 
(E143-01), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-4036; and email address: 
[email protected]. For specific information regarding the risk 
modeling methodology, contact Mr. Mark Morris, 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) 541-5416; and email 
address: [email protected]. For information about the applicability 
of the NESHAP to a particular entity, contact Ms. Marcia Mia, Office of 
Enforcement and Compliance Assurance, U.S. Environmental Protection 
Agency, WJC South Building, 1200 Pennsylvania Ave. NW, Washington, DC 
20460; telephone number: (202) 564-7042; and email address: 
[email protected].

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:

ACC American Chemistry Council
APCD air pollution control device
ASME American Society of Mechanical Engineers
BAAQMD Bay Area Air Quality Management District
BTF beyond-the-floor
Btu/scf British thermal units per standard cubic foot
CAA Clean Air Act
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CO2 carbon dioxide
CRA Congressional Review Act
EFR external floating roof
EMACT Ethylene Production MACT
EPA Environmental Protection Agency
FTIR Fourier transform infrared spectrometry
gpm gallons per minute
GMACT Generic Maximum Achievable Control Technology
HAP hazardous air pollutant(s)
HI hazard index
HQ hazard quotient
IBR incorporation by reference
ICR Information Collection Request
IFR internal floating roof
km kilometer
kPa kilopascals
LDAR leak detection and repair
LEL lower explosive limit
MACT maximum achievable control technology
m\3\ cubic meter
Mg/yr megagrams per year
MIR maximum individual risk
MTVP maximum true vapor pressure
NAICS North American Industry Classification System
NESHAP national emission standards for hazardous air pollutants
NHVcz net heating value in the combustion zone gas
NHVvgnet heating value in the vent gas
NOCS Notification of Compliance Status
NPDES National Pollutant Discharge Elimination System
NRDC Natural Resources Defense Council
NTTAA National Technology Transfer and Advancement Act
OMB Office of Management and Budget
POM polycyclic organic matter
ppm parts per million
ppmv parts per million by volume
PRA Paperwork Reduction Act
PRD pressure relief device(s)
psig pounds per square inch gauge
REL reference exposure level
RFA Regulatory Flexibility Act
RTR residual risk and technology review
SCAQMD South Coast Air Quality Management District
SSM startup, shutdown, and malfunction
TAC Texas Administrative Code
TCEQ Texas Commission on Environmental Quality
The Court United States Court of Appeals for the District of 
Columbia Circuit
TOSHI target organ-specific hazard index
tpy tons per year
UMRA Unfunded Mandates Reform Act
VCS voluntary consensus standards
VOC volatile organic compound(s)

    Background information. On October 9, 2019, the EPA proposed 
revisions to the Generic Maximum Achievable Control Technology (GMACT) 
Standards NESHAP based on our RTR for the Ethylene Production source 
category. In this action, we are finalizing decisions and revisions for 
the rule. We summarize some of the more significant comments we timely 
received regarding the proposed rule and provide our responses in this 
preamble. A summary of all other public comments on the proposal and 
the EPA's responses to those comments is available in the

[[Page 40387]]

Summary of Public Comments and Responses for Risk and Technology Review 
for Ethylene Production, in Docket ID No. EPA-HQ-OAR-2017-0357. A 
``tracked changes'' version of the regulatory language that 
incorporates the changes in this action is available in the docket.
    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. Judicial Review and Administrative Reconsideration
II. Background
    A. What is the statutory authority for this action?
    B. What is the Ethylene Production source category and how does 
the NESHAP regulate HAP emissions from the source category?
    C. What changes did we propose for the Ethylene Production 
source category in our October 9, 2019, RTR proposal?
III. What is included in this final rule?
    A. What are the final rule amendments based on the risk review 
for the Ethylene Production source category?
    B. What are the final rule amendments based on the technology 
review for the Ethylene Production source category?
    C. What are the final rule amendments pursuant to CAA section 
112(d)(2) and (3) for the Ethylene Production source category?
    D. What are the final rule amendments addressing emissions 
during periods of SSM?
    E. What other changes have been made to the NESHAP?
    F. What are the effective and compliance dates of the standards?
IV. What is the rationale for our final decisions and amendments for 
the Ethylene Production source category?
    A. Residual Risk Review for the Ethylene Production Source 
Category
    B. Technology Review for the Ethylene Production Source Category
    C. Amendments Pursuant to CAA Section 112(d)(2) and (d)(3) for 
the Ethylene Production Source Category
    D. Amendments Addressing Emissions During Periods of SSM
    E. Technical Amendments to the EMACT Standards
V. Summary of Cost, Environmental, and Economic Impacts and 
Additional Analyses Conducted
    A. What are the affected facilities?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What analysis of environmental justice did we conduct?
    F. What analysis of children's environmental health did we 
conduct?
VI. Statutory and Executive Order Reviews
    A. Executive Orders 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 13771: Reducing Regulations and Controlling 
Regulatory Costs
    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    H. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR part 51
    K. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    L. Congressional Review Act (CRA)

I. General Information

A. Does this action apply to me?

    Regulated entities. Categories and entities potentially regulated 
by this action are shown in Table 1 of this preamble.

 Table 1--NESHAP and Industrial Source Categories Affected by This Final
                                 Action
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          Source category                  NESHAP         NAICS \1\ code
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Ethylene Production...............  GMACT Standards.....          325110
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\1\ North American Industry Classification System.

    Table 1 of this preamble is not intended to be exhaustive, but 
rather to provide a guide for readers regarding entities likely to be 
affected by the final action for the source category listed. To 
determine whether your facility is affected, you should examine the 
applicability criteria in the appropriate NESHAP. If you have any 
questions regarding the applicability of any aspect of this NESHAP, 
please contact the appropriate person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section of this preamble.

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 final action will also be available on the internet. Following 
signature by the EPA Administrator, the EPA will post a copy of this 
final action at: https://www.epa.gov/stationary-sources-air-pollution/acetal-resins-acrylic-modacrylic-fibers-carbon-black-hydrogen. 
Following publication in the Federal Register, the EPA will post the 
Federal Register version and key technical documents at this same 
website.
    Additional information is available on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/risk-and-technology-review-national-emissions-standards-hazardous. This information 
includes an overview of the RTR program and links to project websites 
for the RTR source categories.

C. Judicial Review and Administrative Reconsideration

    Under the Clean Air Act (CAA) section 307(b)(1), judicial review of 
this final action is available only by filing a petition for review in 
the United States Court of Appeals for the District of Columbia Circuit 
(the Court) by September 4, 2020. Under CAA section 307(b)(2), the 
requirements established by this final rule may not be challenged 
separately in any civil or criminal proceedings brought by the EPA to 
enforce the requirements.
    Section 307(d)(7)(B) of the CAA further provides that only an 
objection to a rule or procedure which was raised with reasonable 
specificity during the period for public comment (including any public 
hearing) may be raised during judicial review. This section also 
provides a mechanism for the EPA to reconsider the rule if the person 
raising an objection can demonstrate to the Administrator that it was 
impracticable to raise such objection within the period for public 
comment or if the grounds for such objection arose after the period for 
public comment (but within the time specified for judicial review) and 
if such objection is of central relevance to the outcome of the rule. 
Any person seeking to make such a demonstration should submit a 
Petition for Reconsideration to the Office of the Administrator, U.S. 
EPA, Room 3000, WJC South Building,

[[Page 40388]]

1200 Pennsylvania Ave. NW, Washington, DC 20460, with a copy to both 
the person(s) listed in the preceding FOR FURTHER INFORMATION CONTACT 
section, and the Associate General Counsel for the Air and Radiation 
Law Office, Office of General Counsel (Mail Code 2344A), U.S. EPA, 1200 
Pennsylvania Ave. NW, Washington, DC 20460.

II. Background

A. What is the statutory authority for this action?

    Section 112 of the CAA establishes a two-stage regulatory process 
to address emissions of HAP from stationary sources. In the first 
stage, we must identify categories of sources emitting one or more of 
the HAP listed in CAA section 112(b) and then promulgate technology-
based NESHAP for those sources. ``Major sources'' are those that emit, 
or have the potential to emit, any single HAP at a rate of 10 tpy or 
more, or 25 tpy or more of any combination of HAP. For major sources, 
these standards are commonly referred to as maximum achievable control 
technology (MACT) standards and must reflect the maximum degree of 
emission reductions of HAP achievable (after considering cost, energy 
requirements, and non-air quality health and environmental impacts). In 
developing MACT standards, CAA section 112(d)(2) directs the EPA to 
consider the application of measures, processes, methods, systems, or 
techniques, including, but not limited to, those that reduce the volume 
of or eliminate HAP emissions through process changes, substitution of 
materials, or other modifications; enclose systems or processes to 
eliminate emissions; collect, capture, or treat HAP when released from 
a process, stack, storage, or fugitive emissions point; are design, 
equipment, work practice, or operational standards; or any combination 
of the above.
    For these MACT standards, the statute specifies certain minimum 
stringency requirements, which are referred to as MACT floor 
requirements, and which may not be based on cost considerations. See 
CAA section 112(d)(3). For new sources, the MACT floor cannot be less 
stringent than the emission control achieved in practice by the best-
controlled similar source. The MACT standards for existing sources can 
be less stringent than floors for new sources, but they cannot be less 
stringent than the average emission 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, we must also consider control options that are more 
stringent than the floor under CAA section 112(d)(2). We may establish 
standards more stringent than the floor, based on the consideration of 
the cost of achieving the emissions reductions, any non-air quality 
health and environmental impacts, and energy requirements.
    In the second stage of the regulatory process, the CAA requires the 
EPA to undertake two different analyses, which we refer to as the 
technology review and the residual risk review. Under the technology 
review, we must review the technology-based standards and revise them 
``as necessary (taking into account developments in practices, 
processes, and control technologies)'' no less frequently than every 8 
years, pursuant to CAA section 112(d)(6). Under the residual risk 
review, we must evaluate the risk to public health remaining after 
application of the technology-based standards and revise the standards, 
if necessary, to provide an ample margin of safety to protect public 
health or to prevent, taking into consideration costs, energy, safety, 
and other relevant factors, an adverse environmental effect. The 
residual risk review is required within 8 years after promulgation of 
the technology-based standards, pursuant to CAA section 112(f). In 
conducting the residual risk review, if the EPA determines that the 
current standards provide an ample margin of safety to protect public 
health, it is not necessary to revise the MACT standards pursuant to 
CAA section 112(f).\1\ For more information on the statutory authority 
for this rule, see 84 FR 54278, October 9, 2019.
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    \1\ The Court has affirmed this approach of implementing CAA 
section 112(f)(2)(A): NRDC v. EPA, 529 F.3d 1077, 1083 (DC 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.'').
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B. What is the Ethylene Production source category and how does the 
NESHAP regulate HAP emissions from the source category?

    The Ethylene Production MACT standards (herein called the EMACT 
standards) for the Ethylene Production source category are contained in 
the GMACT NESHAP which also includes MACT standards for several other 
source categories. The EMACT standards were promulgated on July 12, 
2002 (67 FR 46258), and codified at 40 CFR part 63, subparts XX and YY. 
The EMACT standards regulate HAP emissions from ethylene production 
units located at major sources. An ethylene production unit is a 
chemical manufacturing process unit in which ethylene and/or propylene 
are produced by separation from petroleum refining process streams or 
by subjecting hydrocarbons to high temperatures in the presence of 
steam. The EMACT defines the affected source as all storage vessels, 
ethylene process vents, transfer racks, equipment, waste streams, heat 
exchange systems, and ethylene cracking furnaces and associated 
decoking operations that are associated with each ethylene production 
unit located at a major source as defined in CAA section 112(a).
    As of January 1, 2017, there were 26 facilities in operation and 
subject to the EMACT standards. We are also aware of the expansion and 
construction of several facilities. Based upon this anticipated growth 
for the Ethylene Production source category, we estimate that a total 
of 31 facilities will ultimately be subject to the EMACT standards and 
complying with this final rule over the course of the next 3 years. The 
source category and the EMACT standards are further described in the 
October 9, 2019, RTR proposal. See 84 FR 54278.

C. What changes did we propose for the Ethylene Production source 
category in our October 9, 2019, RTR proposal?

    On October 9, 2019, the EPA published a proposed rule in the 
Federal Register for the EMACT standards of the GMACT NESHAP, 40 CFR 
part 63, subparts XX and YY, that took into consideration the RTR 
analyses. We proposed to find that the risks from the source category 
are acceptable, the current standards provide an ample margin of safety 
to protect public health, and more stringent standards are not 
necessary to prevent an adverse environmental effect. In addition, 
pursuant to the technology review for the Ethylene Production source 
category, we proposed that no revisions to the current standards are 
necessary for ethylene process vents, transfer racks, equipment leaks, 
and waste streams; however, we did propose changes for storage vessels 
and heat exchanger systems. We proposed revisions to the storage 
vessels control applicability requirements, pursuant to CAA section 
112(d)(6), to tighten both the threshold for maximum true vapor 
pressure (MTVP) of total organic HAP (i.e., decreasing it from 3.4 
kilopascals (kPa) or greater to 0.69 kPa or greater) and the threshold 
for storage vessel capacity (i.e., decreasing it from 95 cubic meter

[[Page 40389]]

(m\3\) to 59 m\3\) and to require storage vessels meeting these 
criteria to reduce emissions of total organic HAP by 98 weight-percent 
or use a floating roof storage vessel subject to the requirements of 40 
CFR part 63, subpart WW. In addition, we proposed revisions to the heat 
exchange system requirements, pursuant to CAA section 112(d)(6), to 
require owners or operators to use the Modified El Paso Method and 
repair leaks of total strippable hydrocarbon concentration (as methane) 
in the stripping gas of 6.2 parts per million by volume (ppmv) or 
greater.
    We also proposed the following amendments:
     Revisions to the operating and monitoring requirements for 
flares used as air pollution control devices (APCDs), pursuant to CAA 
section 112(d)(2) and (3);
     requirements and clarifications for periods of SSM and 
bypasses, including for pressure relief device(s) (PRD) releases, 
bypass lines on closed vent systems, in situ sampling systems, 
maintenance activities, and certain gaseous streams routed to a fuel 
gas system, pursuant to CAA section 112(d)(2) and (3);
     work practice standards for decoking ethylene cracking 
furnaces (i.e., minimizing emissions from the coke combustion 
activities in an ethylene cracking furnace), pursuant to CAA section 
112(d)(2) and (3);
     revisions to the SSM provisions of the NESHAP (in addition 
to those related to flares, vent control bypasses, or ethylene cracking 
furnace decoking operations) in order to ensure that they are 
consistent with the Court decision in Sierra Club v. EPA, 551 F. 3d 
1019 (DC Cir. 2008), which vacated two provisions that exempted source 
owners and operators from the requirement to comply with otherwise 
applicable CAA section 112(d) emission standards during periods of SSM;
     a requirement for electronic submittal of performance test 
results and reports, and Notification of Compliance Status (NOCS) 
reports;
     removal of certain exemptions for once-through heat 
exchange systems;
     overlap provisions for equipment at ethylene production 
facilities subject to both the EMACT standards and synthetic organic 
chemicals manufacturing equipment leak standards at 40 CFR part 60, 
subpart VVa;
     IBR of an alternative test method for EPA Methods 3A and 
3B (for the manual procedures only and not the instrumental 
procedures);
     IBR of an alternative test method for EPA Method 18 (with 
caveats);
     IBR of an alternative test method for EPA Method 320 (with 
caveats); and
     several minor editorial and technical changes in the 
subpart.

III. What is included in this final rule?

    This action finalizes the EPA's determinations pursuant to the RTR 
provisions of CAA section 112 for the Ethylene Production source 
category and amends the EMACT standards based on those determinations. 
This action also finalizes other changes to the NESHAP, including 
adding requirements and clarifications for periods of SSM and bypasses; 
revisions to the operating and monitoring requirements for flares used 
as APCDs; adding provisions for electronic reporting of performance 
test results and reports, NOCS reports, and Periodic Reports; and other 
minor editorial and technical changes. This action also reflects 
several changes to the October 9, 2019 RTR proposal in consideration of 
comments received during the public comment period as described in 
section IV of this preamble.

A. What are the final rule amendments based on the risk review for the 
Ethylene Production source category?

    This section describes the final amendments to the EMACT standards 
being promulgated pursuant to CAA section 112(f). The EPA proposed no 
changes to the EMACT standards based on the risk reviews conducted 
pursuant to CAA section 112(f). In this action, we are finalizing our 
proposed determination that risks from this source category are 
acceptable, and that the standards provide an ample margin of safety to 
protect public health and prevent an adverse environmental effect. 
Section IV.A.3 of this preamble provides a summary of key comments we 
received regarding risk review and our responses.

B. What are the final rule amendments based on the technology review 
for the Ethylene Production source category?

    The EPA is finalizing its proposed determination in the technology 
review that there are no developments in practices, processes, and 
control technologies that warrant revisions to the EMACT standards for 
process vents, transfer racks, equipment leaks, and waste streams in 
this source category. Therefore, we are not finalizing revisions to the 
EMACT standards for these emission sources under CAA section 112(d)(6). 
Also, based on comments received on the proposed rulemaking, we are not 
finalizing the proposed revisions to the EMACT standards for storage 
vessels under CAA section 112(d)(6) to tighten the control 
applicability thresholds for MTVP of total organic HAP (i.e., 
decreasing it from 3.4 kPa or greater to 0.69 kPa or greater) and 
storage vessel capacity (i.e., decreasing it from 95 m\3\ to 59 m\3\).
    For heat exchange systems, we determined that there are 
developments in practices, processes, and control technologies that 
warrant revisions to the EMACT standards for this source category. 
Therefore, to satisfy the requirements of CAA section 112(d)(6), we are 
revising the EMACT standards, consistent with the October 9, 2019, RTR 
proposal, to include revisions to the heat exchange system requirements 
to require owners or operators to use the Modified El Paso Method and 
repair leaks of total strippable hydrocarbon concentration (as methane) 
in the stripping gas of 6.2 ppmv or greater. In addition, based on 
comments received on the proposed rulemaking, we are also including an 
alternative mass-based leak action level of total strippable 
hydrocarbon equal to or greater than 0.18 kilograms per hour for heat 
exchange systems with a recirculation rate of 10,000 gallons per minute 
(gpm) or less.
    Section IV.B.3 of this preamble provides a summary of key comments 
we received on the technology review and our responses.

C. What are the final rule amendments pursuant to CAA section 112(d)(2) 
and (3) for the Ethylene Production source category?

    Consistent with Sierra Club v. EPA 551 F. 3d 1019 (D.C. Cir. 2008) 
and the October 9, 2019, RTR proposal, we are revising monitoring and 
operational requirements for flares to ensure that ethylene production 
facilities that use flares as APCDs meet the EMACT standards at all 
times when controlling HAP emissions. In addition, we are adding 
provisions and clarifications for periods of SSM and bypasses, 
including PRD releases, bypass lines on closed vent systems, in situ 
sampling systems, maintenance activities, and certain gaseous streams 
routed to a fuel gas system to ensure that CAA section 112 standards 
apply continuously. Also, for the same reason, we are adopting the 
proposed decoking operations work practice standards into the final 
rule with only minor changes, such as adding delay of repair provisions 
to the flame impingement inspection requirements, adding clarifying 
text to the carbon dioxide (CO2) monitoring, coil outlet 
temperature monitoring, air removal, and radiant tube(s) treatment 
requirements, and removing unnecessary recordkeeping associated

[[Page 40390]]

with the time each isolation valve inspection is performed and the 
results of that inspection even if no problem was found. For details 
about these minor changes, refer to Section 6.7 of the document, 
Summary of Public Comments and Responses for the Risk and Technology 
Reviews for the Ethylene Production Source Category, available in the 
docket for this action.
    Lastly, based on comments received on the proposed rulemaking, we 
are adding a separate standard for storage vessel degassing for storage 
vessels subject to the control requirements in Table 7 to 40 CFR 
63.1103(e)(3)(b) and (e)(3)(c).
    Section IV.C.3 of this preamble provides a summary of key comments 
we received on the CAA section 112(d)(2) and (3) provisions and our 
responses.

D. What are the final rule amendments addressing emissions during 
periods of SSM?

    We are finalizing the proposed amendments to the EMACT standards to 
remove and revise provisions related to SSM. In its 2008 decision in 
Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), the Court vacated 
portions of two provisions in the EPA's CAA section 112 regulations 
governing the emissions of HAP during periods of SSM. Specifically, the 
Court vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 
(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. As detailed in section IV.E.1 of the 
proposal preamble, the Ethylene Production NESHAP requires that 
standards apply at all times (see 40 CFR 63.1108(a)(4)(i)), consistent 
with the Court decision in Sierra Club v. EPA, 551 F. 3d 1019 (D.C. 
Cir. 2008). We determined that facilities in this source category can 
generally meet the applicable EMACT standards at all times, including 
periods of startup and shutdown. As discussed in the proposal preamble, 
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, although the EPA has the discretion to set 
standards for malfunctions where feasible. Where appropriate, and as 
discussed in section III.C of this preamble, we are also finalizing 
alternative standards for certain emission points during periods of SSM 
to ensure a continuous CAA section 112 standard applies ``at all 
times.'' Other than for those specific emission points discussed in 
section III.C of this preamble, the EPA determined that no additional 
standards are needed to address emissions during periods of SSM.
    We are also finalizing, as proposed, eliminating SSM exemptions for 
waste streams at facilities with a total annual benzene less than 10 
megagrams per year (Mg/yr) and amending language in the definitions of 
``dilution steam blowdown waste stream'' and ``spent caustic waste 
stream'' at 40 CFR 63.1082(b) to remove the exclusion for streams 
generated from sampling, maintenance activities, or shutdown purges. In 
addition, we are finalizing a revision to the performance testing 
requirements at 40 CFR 63.1108(b)(4)(ii)(B). The final performance 
testing provisions do not include the language that precludes startup 
and shutdown periods from being considered ``representative'' for 
purposes of performance testing, and instead allows performance testing 
during periods of startup or shutdown if specified by the 
Administrator. However, the final performance testing provisions 
prohibit performance testing during malfunctions because these 
conditions are not representative of normal operating conditions. The 
final rule also requires that operators maintain records to document 
that operating conditions during the test represent normal operations.
    The legal rationale and detailed changes for SSM periods that we 
are finalizing here are set forth in the proposed rule. See 84 FR 
54278, October 9, 2019. Also, based on comments received during the 
public comment period, we are revising 40 CFR 63.1103(e)(9) to 
sufficiently address the SSM exemption provisions from subparts 
referenced by the EMACT standards. For example, in addition to what we 
proposed, we are also clarifying that the certain referenced provisions 
do not apply when demonstrating compliance with the EMACT standards, 
such as phrases like ``other than a start-up, shutdown, or 
malfunction'' in the recordkeeping and reporting requirements of 40 CFR 
63, subparts SS and UU. We are also not removing as proposed the term 
``breakdowns'' in 40 CFR 63.998(b)(2)(i) as well as 40 CFR 
63.998(d)(1)(ii) in its entirety.
    Section IV.D.3 of this preamble provides a summary of key comments 
we received on the SSM provisions and our responses.

E. What other changes have been made to the NESHAP?

    This rule also finalizes, as proposed, revisions to several other 
NESHAP requirements. We describe these revisions in this section as 
well as other revisions that have changed since proposal. To increase 
the ease and efficiency of data submittal and data accessibility, we 
are finalizing, as proposed, a requirement that owners and operators of 
facilities in the Ethylene Production source category submit electronic 
copies of certain required performance test results and reports and 
NOCS reports through the EPA's Central Data Exchange (CDX) website 
using an electronic performance test report tool called the Electronic 
Reporting Tool. In addition, in the final rule, we are correcting an 
error to clarify that Periodic Reports must also be submitted 
electronically (i.e., through the EPA's CDX using the appropriate 
electronic report template for this subpart) beginning no later than 
the compliance dates specified in 40 CFR 63.1102(c) or once the report 
template has been available on the Compliance and Emissions Data 
Reporting Interface (CEDRI) website for at least 1 year, whichever date 
is later. Furthermore, we are finalizing, as proposed, provisions that 
allow facility operators the ability to seek extensions for submitting 
electronic reports for circumstances beyond the control of the 
facility, i.e., for a possible outage in the CDX or CEDRI or for a 
force majeure event in the time just prior to a report's due date, as 
well as the process to assert such a claim.
    To correct a disconnect between having a National Pollutant 
Discharge Elimination System (NPDES) permit that meets certain 
allowable discharge limits at the discharge point of a facility (e.g., 
outfall) and being able to adequately identify a leak, we are 
finalizing, as proposed, the removal of certain exemptions for once-
through heat exchange systems to comply with cooling water monitoring 
requirements.\2\ Further, based on comments received on the proposed 
rulemaking, we are clarifying that the calibration drift assessment 
provisions at 40 CFR 60.485a(b)(2) apply only if the owner or

[[Page 40391]]

operator is subject to those requirements in 40 CFR part 60, subpart 
VVa [see the 40 CFR part 60, subpart VVa overlap provisions in the 
final rule at 40 CFR 63.1100(g)(4)(iii)].
---------------------------------------------------------------------------

    \2\ Cooling water from a once-through heat exchange system at a 
petrochemical plant can be mixed with other sources of water (e.g., 
cooling water used in once-through heat exchange systems in non-
ethylene source categories, stormwater, treated wastewater, etc.) in 
sewers, trenches, and ponds prior to discharge from the plant. If 
this point of discharge from the plant is into a ``water of the 
United States,'' then the facility is required to have a NPDES 
permit and to meet certain pollutant discharge limits.
---------------------------------------------------------------------------

    We are finalizing all of the revisions that we proposed for 
clarifying text or correcting typographical errors, grammatical errors, 
and cross-reference errors. These editorial corrections and 
clarifications are summarized in Table 9 of the proposal. See 84 FR 
54278, October 9, 2019. We are also including several additional minor 
clarifying edits in the final rule based on comments received during 
the public comment period. We did not receive many substantive comments 
on these other amendments in the Ethylene Production RTR proposal. The 
comments and our specific responses to these items can be found in the 
document, Summary of Public Comments and Responses for the Risk and 
Technology Reviews for the Ethylene Production Source Category, 
available in the docket for this action.

F. What are the effective and compliance dates of the standards?

    The revisions to the EMACT standards being promulgated in this 
action are effective on July 6, 2020. From our assessment of the 
timeframe needed for implementing the entirety of the revised 
requirements (see 84 FR 54278, October 9, 2019), the EPA proposed a 
period of 3 years to be the most expeditious compliance period 
practicable. Although opposing comments regarding the proposed 
compliance dates were received during the public comment period, we are 
finalizing the 3-year compliance period as proposed. Amendments to 
EMACT standards for adoption under CAA sections 112(d)(2) and (3) and 
112(d)(6) are subject to the compliance deadlines outlined in the CAA 
under section 112(i). For existing sources, CAA section 112(i) provides 
that the compliance date shall be as expeditiously as practicable, but 
no later than 3 years after the effective date of the standard. For new 
sources, compliance is required by the effective date of the final 
amendments or upon startup, whichever is later. As explained in the 
preamble to the proposed rule (84 FR 54278, October 9, 2019), the EPA 
recognizes the confusion that multiple different compliance dates for 
individual requirements would create and the additional burden such an 
assortment of dates would impose; and from our assessment of the 
timeframe needed for compliance with the entirety of the revised 
requirements, the EPA considers a period of 3 years after the effective 
date of the final rule to be the most expeditious compliance period 
practicable. Furthermore, as discussed in sections III and IV of this 
preamble, we are adding separate work practice standards to the final 
rule for the following SSM activities/events: (1) Periods of SSM for 
when flares are used as an APCD, (2) periods of SSM for certain vent 
streams (i.e. PRD releases and maintenance vents), (3) vent control 
bypasses for certain vent streams (i.e., closed vent systems containing 
bypass lines, in situ sampling systems, and flares connected to fuel 
gas systems), and (4) decoking operations for ethylene cracking 
furnaces. The provisions being finalized are similar to the 
requirements promulgated in the Petroleum Refinery NESHAP. As we 
discovered during the Petroleum Refinery NESHAP rulemaking, the 
challenges faced by affected sources in complying with these 
requirements necessitated additional compliance time from what was 
promulgated, eventually having to move the original compliance date of 
these provisions from February 1, 2016, to August 1, 2018, an 
additional 2 and a half years.\3\ Therefore the 3 year compliance date 
that was proposed for the EMACT standards provides a consistent time 
allowance to affected sources as was needed for Petroleum Refineries to 
fully implement the work practice standards. Thus, the compliance date 
of the final amendments for all existing affected sources, and all new 
affected sources that commence construction or reconstruction after 
December 6, 2000, and on or before October 9, 2019, is no later than 
July 6, 2023, or upon startup, whichever is later. The compliance date 
of the final amendments for all ethylene production new affected 
sources that commenced construction or reconstruction after October 9, 
2019, is the effective date of these final rule amendments to the EMACT 
standards of July 6, 2020, or upon startup, whichever is later.
---------------------------------------------------------------------------

    \3\ https://www.epa.gov/sites/production/files/2018-07/documents/petrefinery_compliance_ext_factsheet.pdf.
---------------------------------------------------------------------------

IV. What is the rationale for our final decisions and amendments for 
the Ethylene Production source category?

    For each issue, this section provides a description of what we 
proposed and what we are finalizing for the issue, the EPA's rationale 
for the final decisions and amendments, and a summary of key comments 
and responses. For all comments not discussed in this preamble, comment 
summaries and the EPA's responses can be found in the comment summary 
and response document available in the docket.

A. Residual Risk Review for the Ethylene Production Source Category

1. What did we propose pursuant to CAA section 112(f) for the Ethylene 
Production source category?
    Pursuant to CAA section 112(f), the EPA conducted a residual risk 
review and presented the results of this review, along with our 
proposed decisions regarding risk acceptability and ample margin of 
safety, in the October 9, 2019, proposed rule for 40 CFR part 63, 
subparts XX and YY (84 FR 54278). The results of the risk assessment 
for the proposal are presented briefly in Table 2 of this preamble. 
More detail is in the residual risk technical support document, 
Residual Risk Assessment for the Ethylene Production Source Category in 
Support of the 2019 Risk and Technology Review Proposed Rule, which is 
available in the docket for this rulemaking.

[[Page 40392]]



                                                                 Table 2--Ethylene Production Inhalation Risk Assessment Results
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                      Maximum  individual  cancer     Estimated population at  increased       Estimated annual  cancer       Maximum chronic  noncancer     Maximum  screening
                                       risk  (in 1 million) \2\        risk of  cancer >= 1-in-1 million      incidence  (cases per year)              TOSHI \3\             acute noncancer HQ
                                   ----------------------------------------------------------------------------------------------------------------------------------------          \4\
                                            Based on . . .                      Based on . . .                      Based on . . .                  Based on . . .         ---------------------
     Number of facilities \1\      ----------------------------------------------------------------------------------------------------------------------------------------
                                        Actual         Allowable                                                Actual         Allowable        Actual         Allowable      Based on  actual
                                       emissions       emissions     Actual  emissions       Allowable         emissions       emissions       emissions       emissions      emissions  level
                                         level           level             level         emissions  level        level           level           level           level
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
31................................             100             100  2.8 million.......  4.6 million.......             0.1             0.2               1               1  HQREL = <1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category. There is only one census block, and one person, at this risk level.
\3\ Maximum target organ-specific hazard index (TOSHI). The target organ systems with the highest TOSHI for the source category are neurological and reproductive. The respiratory TOSHI was
  calculated using the California EPA chronic reference exposure level (REL) for acrolein.
\4\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of hazard quotient (HQ) values. HQ values shown use the lowest
  available acute threshold value, which in most cases is the REL. When an HQ exceeds 1, we also show the HQ using the next lowest available acute dose-response value.

    Using actual emissions data, the results of the proposed inhalation 
risk assessment, as shown in Table 2 of this preamble, indicate the 
estimated cancer maximum individual risk (MIR) is 100-in-1 million, 
with naphthalene and benzene as the major contributors to the risk. 
There is only one census block, and one person, at this risk level. The 
second-highest facility cancer risk is 30-in-1 million. At proposal, 
the total estimated cancer incidence from this source category was 
estimated to be 0.1 excess cancer cases per year, or one excess case in 
every 10 years. Approximately 2.8 million people were estimated to have 
cancer risks above 1-in-1 million from HAP emitted from the facilities 
in this source category. At proposal, the estimated maximum chronic 
noncancer TOSHI for the source category was 1 (neurological and 
respiratory) driven by emissions of manganese and epichlorohydrin.
    Using the MACT-allowable emissions, the risk results at proposal 
for the inhalation risk assessment indicated that the estimated cancer 
MIR was 100-in-1 million with naphthalene and benzene emissions driving 
the risks, and that the estimated maximum chronic noncancer TOSHI was 1 
with manganese and epichlorohydrin as the major contributors to the 
TOSHI. At proposal, the total estimated cancer incidence from this 
source category considering allowable emissions was 0.2 excess cancer 
cases per year or 1 excess case in every 5 years. Based on allowable 
emission rates, 4.6 million people were estimated to have cancer risks 
above 1-in-1 million.
    As shown in Table 2 of this preamble, the reasonable worst-case 
acute HQ (based on the REL) at proposal was less than 1. This value is 
the highest HQ that is outside facility boundaries. No facilities were 
estimated to have an HQ greater than or equal to 1 based on any 
benchmark (REL, acute exposure guideline level, or emergency response 
planning guidelines). In addition, at proposal, we identified emissions 
of arsenic compounds, cadmium compounds, mercury compounds, and 
polycyclic organic matter (POM), all HAP known to be persistent and 
bio-accumulative in the environment. The multipathway risk screening 
assessment resulted in a maximum Tier 2 cancer screening value of 30 
for arsenic and a maximum Tier 3 noncancer screening value of 2 for 
mercury compounds. Based on facility-specific analyses performed for 
mercury for other source categories, we concluded that such analyses 
would reduce the mercury screening value to 1 or lower. In addition, a 
screening-level evaluation of the potential adverse environmental risk 
associated with emissions of arsenic, cadmium, hydrochloric acid, 
hydrofluoric acid, lead, mercury, and POMs indicated that no ecological 
benchmarks were exceeded.
    We weighed all health risk factors, including those shown in Table 
2 of this preamble, in our risk acceptability determination and 
proposed that the risks posed by the Ethylene Production source 
category are acceptable (section IV.C.1 of proposal preamble, 84 FR 
54311, October 9, 2019).
    We then considered whether the existing EMACT standards provide an 
ample margin of safety to protect public health and whether, taking 
into consideration costs, energy, safety, and other relevant factors, 
more stringent standards are required to prevent an adverse 
environmental effect. In considering whether the standards are required 
to provide an ample margin of safety to protect public health, we 
considered the same risk factors that we considered for our 
acceptability determination and also considered the costs, 
technological feasibility, and other relevant factors related to 
emissions control options that might reduce risk associated with 
emissions from the source category. We proposed that additional 
emissions controls for the Ethylene Production source category are not 
necessary to provide an ample margin of safety to protect public health 
and that more stringent standards are not necessary to prevent an 
adverse environmental effect (section IV.C.2 of proposal preamble, 84 
FR 54312, October 9, 2019).
    We also evaluate risk from whole facility emissions in order to 
help put the risks in context. Whole facility (or ``facility-wide'') 
emissions include those regulated under this source category plus all 
other emissions generated at each facility. The results of the chronic 
inhalation cancer risk assessment based on facility-wide emissions are 
more uncertain and rely on the quality of the emissions data collected 
for source categories outside this regulatory review. These emissions 
sources may not undergo the same level of data quality review as those 
being assessed in this regulatory assessment. The estimated maximum 
lifetime individual cancer risk based on facility-wide emissions is 
2,000-in-1 million, with ethylene oxide from non-category (non-ethylene 
production process) emissions driving the risk. The total estimated 
cancer incidence based on facility-wide emissions is 1 excess cancer 
case per year. Approximately 6,500,000 people are estimated to have 
cancer risks above 1-in-1 million from HAP emitted from all sources at 
the facilities in this source category. The estimated maximum chronic 
noncancer hazard index (HI) based on facility-wide emissions is 4 (for 
the respiratory HI), driven by emissions of chlorine from non-category 
(non-ethylene production process) emissions. Approximately 200 people 
are estimated to be exposed to noncancer HI levels above 1.

[[Page 40393]]

2. How did the risk review change for the Ethylene Production source 
category?
    We have not changed any aspect of the risk assessment since the 
October 9, 2019, RTR proposal for the Ethylene Production source 
category.
3. What key comments did we receive on the risk review, and what are 
our responses?
    We received comments in support of and against the proposed 
residual risk review and our determination that no revisions were 
warranted under CAA section 112(f)(2) for the Ethylene Production 
source category. Generally, the comments that were not supportive of 
the determination from the risk reviews suggested changes to the 
underlying risk assessment methodology. For example, some commenters 
stated that the 100-in-1 million lifetime cancer risk cannot be 
considered safe or ``acceptable,'' and the EPA should include emissions 
outside of the source categories in question in the risk assessment and 
assume that pollutants with noncancer health risks have no safe level 
of exposure. After review of all the comments received, we determined 
that no changes were necessary. The comments and our specific responses 
can be found in the document, Summary of Public Comments and Responses 
for the Risk and Technology Reviews for the Ethylene Production Source 
Category, available in the docket for this action.
4. What is the rationale for our final approach and final decisions for 
the risk review?
    As noted in our proposal, the EPA sets standards under CAA section 
112(f)(2) using ``a two-step standard-setting approach, with an 
analytical first step to determine an `acceptable risk' that considers 
all health information, including risk estimation uncertainty, and 
includes a presumptive limit on MIR of approximately 1-in-10 thousand'' 
(84 FR 54278, October 9, 2019; see also 54 FR 38045, September 9, 
1989). We weigh all health risk factors in our risk acceptability 
determination, including the cancer MIR, cancer incidence, the maximum 
cancer TOSHI, the maximum acute noncancer HQ, the extent of noncancer 
risks, the distribution of cancer and noncancer risks in the exposed 
population, multipathway risks, and the risk estimation uncertainties.
    Since proposal, neither the risk assessment nor our determinations 
regarding risk acceptability, ample margin of safety, or adverse 
environmental effects have changed. For the reasons explained in the 
proposed rule, we determined that the risks from the Ethylene 
Production source category are acceptable, the current standards 
provide an ample margin of safety to protect public health, and more 
stringent standards are not necessary to prevent an adverse 
environmental effect. Therefore, we are not revising the EMACT 
standards to require additional controls pursuant to CAA section 
112(f)(2) based on the residual risk review, and we are readopting the 
existing standards under CAA section 112(f)(2).

B. Technology Review for the Ethylene Production Source Category

1. What did we propose pursuant to CAA section 112(d)(6) for the 
Ethylene Production source category?
    Pursuant to CAA section 112(d)(6), the EPA proposed to conclude 
that no revisions to the current EMACT standards are necessary for 
ethylene process vents, transfer racks, equipment leaks, and waste 
streams (sections IV.D.2 through IV.D.5 of proposal preamble, 84 FR 
54314, October 9, 2019). We did not find any developments (since 
promulgation of the original NESHAP) in practices, processes, and 
control technologies that could be applied to ethylene process vents 
and that could be used to reduce emissions from ethylene production 
facilities. We also did not identify any developments in work 
practices, pollution prevention techniques, or process changes that 
could achieve emission reductions from ethylene process vents. For 
transfer racks, we identified one emission reduction option, at 
proposal, to revise the transfer rack applicability threshold (for 
volumetric throughput of liquid loaded) from 76 m\3\ per day to 1.8 
m\3\ per day to reflect the more stringent applicability threshold of 
other chemical sector standards that regulate emissions from transfer 
rack operations (i.e., 40 CFR part 63, subparts F and G and 40 CFR part 
63, subpart FFFF). At proposal, we also identified two developments in 
leak detection and repair (LDAR) practices and processes for equipment 
leaks: (1) Lowering the leak definition for valves in gas and vapor 
service or in light liquid service from 500 parts per million (ppm) to 
100 ppm and (2) lowering the leak definition for pumps in light liquid 
service from 1,000 ppm to 500 ppm. In addition, we identified two 
emission reduction options, at proposal, for waste streams: (1) 
specific performance parameters for an enhanced biological unit beyond 
those required in the Benzene Waste Operations NESHAP and (2) treatment 
of wastewater streams with a volatile organic compounds (VOC) content 
of 750 ppmv or higher by steam stripping prior to any other treatment 
process for facilities with high organic loading rates (i.e., 
facilities with total annualized benzene quantity of 10 Mg/yr or more). 
However, based on the costs and emission reductions for each of the 
proposed options (for transfer racks, equipment leaks, and waste 
streams), we considered none of these options to be cost effective for 
reducing emissions from these emission sources at ethylene production 
units, and we proposed that it is not necessary to revise the EMACT 
standards for these emission sources pursuant to CAA section 112(d)(6).
    Also, pursuant to CAA section 112(d)(6), we proposed revisions to 
the current EMACT standards for storage vessels and heat exchange 
systems (sections IV.D.1 and IV.D.6 of proposal preamble, 84 FR 54314, 
October 9, 2019). For storage vessels, we proposed tightening both the 
applicability threshold for MTVP of total organic HAP (i.e., decreasing 
it from 3.4 kPa or greater to 0.69 kPa or greater) and the 
applicability threshold for storage vessel capacity (i.e., decreasing 
it from 95 m\3\ to 59 m\3\) in Table 7 at 40 CFR 63.1103(e)(3)(a)(1) 
and 40 CFR 63.1103(e)(3)(b)(1), respectively. For heat exchange 
systems, we proposed to add a new provision, 40 CFR 63.1086(e), that 
would require owners or operators to use the Modified El Paso Method to 
monitor for leaks and to repair leaks of total strippable hydrocarbon 
concentration (as methane) in the stripping gas of 6.2 ppmv or greater. 
We also proposed to add a new provision, 40 CFR 63.1088(d), 
establishing a delay of repair action level of total strippable 
hydrocarbon concentration (as methane) in the stripping gas of 62 ppmv, 
that if exceeded during leak monitoring, would require immediate repair 
(i.e., the leak found cannot be put on delay of repair and would be 
required to be repaired within 30 days of the monitoring event). This 
would apply to both monitoring heat exchange systems and individual 
heat exchangers by replacing the use of any 40 CFR part 136 water 
sampling method with the Modified El Paso Method and removing the 
option that allows for use of a surrogate indicator of leaks. Finally, 
we proposed to add a new provision, 40 CFR 63.1087(c), requiring re-
monitoring at the monitoring location where a leak is identified to 
ensure that any leaks found are fixed.

[[Page 40394]]

2. How did the technology review change for the Ethylene Production 
source category?
    The EPA has not changed any aspect of the technology review for 
process vents, transfer racks, equipment leaks, and waste streams since 
the October 9, 2019, RTR proposal for the Ethylene Production source 
category. However, based on comments received on the proposed 
rulemaking, we are not finalizing the proposed revisions to the EMACT 
standards for storage vessels under CAA section 112(d)(6) to tighten 
the applicability threshold for MTVP of total organic HAP (i.e., 
decreasing it from 3.4 kPa or greater to 0.69 kPa or greater) and the 
applicability threshold for storage vessel capacity (i.e., decreasing 
it from 95 m\3\ to 59 m\3\). Moreover, although we are revising the 
EMACT standards for heat exchange systems consistent with the October 
9, 2019, RTR proposal, we are also including, based on comments 
received on the proposed rulemaking, an alternative mass-based leak 
action level of total strippable hydrocarbon equal to or greater than 
0.18 kilograms per hour for heat exchange systems with a recirculation 
rate of 10,000 gpm or less.
3. What key comments did we receive on the technology review, and what 
are our responses?
    The EPA received comments in support of and against the proposed 
technology review amendments and our determination that no revisions 
were warranted under CAA section 112(d)(6) for process vents, transfer 
racks, equipment leaks, and waste streams in the Ethylene Production 
source category and that revisions were warranted for storage vessels 
and heat exchange systems in the Ethylene Production source category. 
Generally, for process vents, transfer racks, equipment leaks, and 
waste streams, the comments were either supportive of the determination 
that no cost-effective developments from the technology review were 
found, or that the Agency should re-open and re-evaluate the MACT 
standards for these emission sources and not consider cost in the 
technology review for the emissions sources. Based on our review of the 
comments received for process vents, transfer racks, equipment leaks, 
and waste streams, we are finalizing our determination that no cost-
effective developments exist and that it is not necessary to revise 
these emission standards under CAA section 112(d)(6).
    For storage vessels, the EPA received additional information from 
commenters on material composition, storage vessels that would be 
affected by the proposed option, and costs necessary for control of the 
storage vessels that would be affected by the proposed control option. 
After review of all the comments received, we determined that it is not 
cost effective to revise the storage vessel control requirements and 
are not finalizing revisions for this emissions source under CAA 
section 112(d)(6).
    For heat exchange systems, the EPA received additional information 
from commenters on costs necessary for control of these sources as well 
as comments on a number of technical clarifications and allowance of 
compliance with an alternative mass-based leak action level should the 
EPA finalize the requirements for heat exchange systems. After review 
of all the comments received, we determined that it is cost effective 
to revise the heat exchange system requirements, and we are finalizing 
revisions for this emissions source under CAA section 112(d)(6) 
however, we are also including, based on comments received on the 
proposed rulemaking, an alternative mass-based leak action level of 
total strippable hydrocarbon equal to or greater than 0.18 kilograms 
per hour for heat exchange systems with a recirculation rate of 10,000 
gpm or less.
    This section provides comment and responses for the key comments 
received regarding the technology review amendments we proposed for 
storage vessels and heat exchange systems. Comment summaries and the 
EPA's responses for additional issues raised regarding the proposed 
requirements resulting from our technology review are in the document, 
Summary of Public Comments and Responses for the Risk and Technology 
Reviews for the Ethylene Production Source Category, available in the 
docket for this action.
    Comment: We received comments in support of and against the 
proposed changes to the storage vessel capacity and vapor pressure 
thresholds and corresponding control requirements. Most of the 
commenters opposed to the proposed requirements said the EPA's proposed 
changes to the capacity and vapor pressure thresholds for control of 
storage vessel emissions are not cost-effective. The commenters said 
that based on their analysis and using the EPA percentages of annual 
cost components (9.47-percent capital recovery, 5-percent maintenance, 
4 percent for taxes, insurance, and administration, $380 per ton of VOC 
recovered), the average capital cost for control is approximately $1.2 
million per tank, the average annual cost is $216,000 per tank, and the 
cost effectiveness of the control option is $108,000 per ton of VOC. 
The commenters said that their estimates account for materials and 
installation, in addition to the necessary cleaning and preparation 
required to install the floating roof or make the necessary connections 
to the closed vent system. The commenters asserted that degassing and 
cleaning do not appear to be included in the EPA's cost calculation and 
should be added as these are necessary steps to prepare the tanks for 
modification and ensure worker safety. The commenter said that their 
cost estimate is much higher than the EPA's estimate; and the 
commenters contended the EPA's estimated capital investment for the 
installation of an internal floating roof (IFR) on an existing fixed 
roof tank is unrealistic and should be revised. The commenters stated 
that at least one facility would install a new closed vent system to an 
existing control device, instead of an IFR, due to more favorable 
economics or site-specific constraints. The commenters said that the 
cost of this closed vent system is approximately $825,000 per tank 
(materials and installation). The commenters also provided certain 
technical details and cost information that they claimed as CBI.
    Response: We are not finalizing the proposed requirements to 
tighten the storage vessel capacity and MTVP thresholds in response to 
comments and additional costs information that the EPA received on the 
proposal. Specifically, we reviewed and agree with the additional 
information submitted by commenters on the specific storage vessels 
that would be affected (e.g., material composition and vapor pressure 
data, costs to control those storage vessels, and estimated emissions 
reductions). Importantly, the CBI submitted by one commenter provided 
details showing that installation of an IFR was not an option for their 
specific facility due to technical constraints. In addition, given that 
the proposed option would result in 10 tpy of VOC reductions nationwide 
(and lower emissions reductions for HAP) and cost over $1 million 
annually, we find the control of storage vessels at $108,000 per ton 
for VOC (and higher cost effectiveness for HAP) is not cost effective. 
Further, the proposed option would only affect six of the approximately 
248 storage vessels in the source category [assuming an average of 
eight storage vessels per facility from the CAA section 114 Information 
Collection Request (ICR) data] and would not meaningfully reduce 
overall

[[Page 40395]]

emissions from the source category. Given all of this information, we 
are not finalizing the proposed requirements to tighten the storage 
vessel capacity and MTVP thresholds and are keeping the current MACT 
level of control for storage vessels in place.
    Comment: A commenter stated that the proposed technology review 
amendments do not represent MACT and noted three control options were 
identified for storage vessels, but only one was adopted into the 
proposed rule. The commenter emphasized that many new ethylene 
production facilities are planned to be constructed or are under 
construction and the EPA must address their HAP emissions by applying 
the most stringent control technologies.
    Similarly, another commenter stated that it would be unlawful, 
arbitrary, and capricious for the EPA not to set stronger standards for 
emissions from storage vessels. The commenter stated that although the 
EPA identified two other developments in technology for storage 
vessels: (1) Requiring LDAR for fittings on fixed roof storage vessels 
(e.g., access hatches) using EPA Method 21, and the use of liquid level 
overfill warning monitors and roof landing warning monitors on storage 
vessels with an IFR or external floating roof (EFR); and (2) the 
conversion of EFRs to IFRs through use of geodesic domes, the EPA 
declined to require these controls simply because the control options 
were not cost effective. The commenter insisted that the EPA failed to 
show why the cost-per-ton it found for storage vessel developments are 
inappropriate and failed to show why further reductions are not 
required to satisfy CAA sections 112(d)(6) and (f)(2). The commenter 
noted the costs the EPA found ($6,120 per ton HAP to $44,100 per ton 
HAP) are lower than other rules where the EPA determined the cost-per-
ton to be appropriate. As an example, the commenter cited the cost-per-
ton from secondary lead smelting that were considered reasonable, 
ranging from $330,000 per ton to $1,500,000 per ton (77 FR 576, January 
5, 2012). The commenter stated that because the EPA found higher cost-
reduction ratios appropriate, it is arbitrary and capricious for the 
EPA not to require greater reductions for storage vessels, when they 
are achievable and would provide more protection for public health, as 
statutorily provided. The commenter asserted that several of these 
developments are already widely in use or required by other regulatory 
agencies. The commenter further argued that the EPA gives no 
explanation for why the Agency considers ``incremental cost 
effectiveness'' to be determinative rather than evaluating costs based 
on ``HAP cost effectiveness'' as it does for other source types, such 
as equipment leaks and waste streams.
    The commenter argued that the EPA's decision to make cost-per-ton 
the standard-setting criterion and to choose a number it deems 
unreasonable, without a rational explanation, is arbitrary and 
capricious. The commenter stated the cost-per-ton of HAP reduction does 
not indicate whether a stronger standard is feasible and does not 
consider whether the industry could bear the costs of additional 
controls. The commenter stated that the ethylene production industry 
generated $50.8 billion in revenue in 2016 and the EPA cannot plausibly 
claim that this industry cannot afford to implement the identified 
storage vessel developments. The commenter noted that cost-per-ton says 
nothing about health risk, and that a ton of HAP is a very large 
amount. The commenter stated that the risk assessment for this source 
category shows the pollutants emitted in ethylene production are known 
to be hazardous at an exposure level of micrograms or less, and the 
carcinogens emitted (e.g., benzene, formaldehyde, naphthalene) have no 
safe level of exposure. In addition, the commenter asserted that no two 
HAP create the same health risks and that reducing tons of one 
pollutant does not produce the same benefit as reducing tons of 
another. The commenter added that the EPA should not base its final 
standards on cost effectiveness at all; the Agency's job is simply to 
determine the ``maximum'' degree of reduction that can be achieved 
considering cost, under CAA section 112(d)(2), and to assure an ``ample 
margin of safety to protect public health'' under CAA section 
112(f)(2). The commenter stressed that if the EPA wishes to consider 
cost effectiveness in any meaningful sense, it cannot rely on the cost-
per-ton, which says nothing about the true effectiveness of reducing 
emissions of highly toxic pollutants, in terms of public health--which 
is a key factor missing from the EPA's analysis. Thus, the commenter 
concluded it was arbitrary and capricious for the EPA to decide that it 
was not necessary to update the standards to account for storage vessel 
developments based on cost.
    The commenter also contended the EPA may consider cost but CAA 
section 112(d)(6) does not authorize the EPA to refuse to update 
standards based on cost. The commenter stated the Court has recognized 
that developments are the core requirement, and if developments have 
occurred, the EPA must account for those. The commenter further claimed 
that the EPA should follow the plain text of CAA section 112(d)(2)-(3) 
and applicable precedent requiring explicit authorization to consider 
cost. The commenter stated the EPA's cost-focused analysis ignores the 
statutory objective of assuring the ``maximum'' achievable degree of 
emission reduction provided in CAA section 112(d)(2), as implemented 
through the technology review. The commenter stated that this analysis 
also ignores the statutory goal of protecting public health, per CAA 
section 112 (f)(2).
    The commenter also stated that although the EPA initially 
considered tightening the threshold for storage vessel capacity from 95 
m\3\ to 38 m\3\, the EPA proposed a threshold of 59 m\3\ because it 
found that ``it would not be cost-effective for this particular storage 
vessel to add additional controls due to its infrequent use.'' The 
commenter contended that the EPA cannot set a higher capacity threshold 
simply based on the cost of installing a control on one affected 
vessel, especially without information or analysis.
    Response: We disagree with the comment that the EPA has an 
obligation to review prior MACT determinations and recalculate MACT 
floors as part of each CAA section 112(d)(6) review given that this 
argument has been repeatedly rejected by the Court. See, e.g., Nat'l 
Ass'n of Surface Finishing v. EPA, 795 F.3d 1 (DC Cir. 2015); 
Association of Battery Recyclers v. EPA, 716 F.3d 667, 673 (DC Cir. 
2013); Natural Resources Defense Council (NRDC) v. EPA, 529 F.3d 1077 
(DC Cir. 2008). In the proposal we neither re-evaluated nor re-opened 
the MACT standard for storage vessels under CAA sections 112(d)(2) and 
(3) in this action. For storage vessels, the revisions we proposed were 
as a result of the RTR under CAA sections 112(d)(6) and (f)(2). As also 
explained at proposal, under section 112(d)(6), the EPA is to review 
the ``emission standards promulgated under'' CAA section 112(d)(2) and 
(3). The EPA has consistently posited that CAA section 112(d)(6) 
focuses on the review of developments that have occurred in a source 
category since the original promulgation of a MACT standard. Similarly, 
the EPA is to conduct a risk review that evaluates whether the emission 
limits--the ``standards promulgated pursuant to subsection (d),'' [CAA 
section 112(f)(2)(A)]--should be made more stringent to reduce the risk 
posed after compliance with the underlying MACT standard. Therefore, 
the EPA does not have an obligation in its technology and

[[Page 40396]]

residual risk review to consider ``hypothetical'' facilities that is, 
facilities that have yet to begin construction (or may never even be 
constructed or operate) and where air emissions from ethylene 
production operations are merely anticipated because said operations do 
not yet exist and facilities have yet to start up. As also previously 
discussed we are not finalizing these proposed revisions under CAA 
section 112(d)(6) because they are not cost effective. In addition, the 
proposed revisions have little to no impact on HAP emissions for the 
source category. With respect to the role of cost in our decisions 
under the technology review, we note that the Court has not required 
the EPA to demonstrate that a technology is ``cost-prohibitive'' in 
order not to require adopting a new technology under CAA section 
112(d)(6); a simple finding that a control is not cost effective is 
enough. See Association of Battery Recyclers, et al. v. EPA, et al., 
716 F.3d 667, 673-74 (D.C. Cir. 2015) (approving the EPA's 
consideration of cost as a factor in its CAA section 112(d)(6) 
decision-making and the EPA's reliance on cost effectiveness as a 
factor in its standard-setting).
    The commenter's comparison of cost-per-ton estimates against other 
rules and other requirements within this final rule is also misplaced. 
The commenter draws a comparison to an analysis for metal HAP in the 
Secondary Lead NESHAP RTR, where those costs per ton were determined to 
be within the range of metal HAP values for other CAA section 112 rules 
(see 77 FR 576, January 5, 2012). However, organic HAP are the issue of 
concern for storage vessels, and the EPA has historically used a 
different and significantly lower cost-effectiveness scale for organic 
HAP versus metal HAP due to their relative toxicity. Generally, for 
organic HAP, we consider a cost effectiveness of $10,000/ton or more to 
be near the upper end of what the EPA has traditionally considered to 
be cost effective for control for these particular type of HAP.
    In addition, we disagree with the commenter that consideration of 
incremental cost effectiveness was an unreasonable approach for 
comparing differing strategies that build upon one another. We note 
that CAA section 112(d)(6) does not prescribe a methodology for the 
agency's costs analysis, and the EPA has sometimes presented cost/ton-
reduced numbers in the supporting analyses for regulations that we 
issue. See for example, Husqvarna AB v. EPA, 254 F. 3d 195 at 200 (D.C. 
Cir. 2001) (``Because section 213 does not mandate a specific method of 
cost analysis, we find reasonable the EPA's choice to consider costs on 
the per ton of emissions removed basis.''). For storage vessels, we 
proposed to tighten the capacity and MTVP thresholds for control (known 
as option SV1 in our technology review memorandum) and also evaluated 
two other control options that built upon option SV1. Option SV1 was 
evaluated in concert with the two other options, including adding 
enhanced monitoring requirements (option SV2) and requiring EFR storage 
vessels to convert to IFR storage vessels via use of geodesic domes 
(option SV3). The costs are presented such that the overall HAP cost 
effectiveness for options SV2 and SV3 also include option SV1, while 
the incremental cost-effectiveness values for options SV2 and SV3 are 
the cost-effectiveness values only for requiring enhanced monitoring 
and only for requiring EFR storage vessels to convert to IFR storage 
vessels via use of geodesic domes, respectively. Simply put, the 
incremental cost-effectiveness values for options SV2 and SV3 do not 
include costs and emissions reductions for option SV1. The commenter 
did not provide additional details on costs or emissions reductions on 
these options; thus, we continue to believe these options are not cost-
effective and are not finalizing them. An incremental cost- 
effectiveness analysis was not needed for equipment leaks or waste 
operations because we did not propose any revisions under our CAA 
section 112(d)(6) technology review for these emission sources. We also 
did not consider control options for these emission sources that would 
build upon each other and necessitate an evaluation of incremental 
costs and, thus, the HAP cost effectiveness for the options presented 
in those analyses are equivalent to the incremental cost- effectiveness 
values presented for options SV2 and SV3 for storage vessels. For 
further information on our technology review for storage vessels, see 
the technical memorandum, Clean Air Act Section 112(d)(6) Technology 
Review for Storage Vessels Located in the Ethylene Production Source 
Category, which is available in Docket ID Item No. EPA-HQ-OAR-2017-
0357-0014.
    Lastly, we disagree with the commenter that it was unreasonable to 
consider an infrequently used storage vessel with a capacity of 58 m\3\ 
(i.e., a storage vessel with a capacity within the threshold of 38 m\3\ 
and 59 m\3\, which we evaluated, but did not propose) with little 
emissions and an extremely high cost-effectiveness value for control in 
setting the size threshold for control in our SV1 option evaluated 
under our CAA section 112(d)(6) review. As explained in the technology 
review memorandum, we first looked at other chemical sector and 
refinery NESHAP for storage vessel control thresholds for capacity and 
MTVP as a starting point and then we used our CAA section 114 ICR data 
to further refine option SV1. Based on our CAA section 114 data, only 
one storage vessel (with a capacity of 58 m\3\) met the most stringent 
requirements for control from other NESHAP compared to the option we 
evaluated and would be impacted were we to evaluate this storage vessel 
in option SV1 (along with the other 12 storage vessels we anticipated 
would also be affected at proposal). Using the information from our CAA 
section 114 request that was submitted for this storage vessel (e.g., 
size, number of tank turnovers, stored material composition), we 
conservatively estimated that this 58 m\3\ storage vessel would only 
have annual emissions of 0.005 tpy of HAP if it had one full turnover 
(even though it reported having none in 2013). Considering the extreme 
case that all these emissions would be reduced from this storage vessel 
if it were required to be controlled, and if we made several other 
assumptions (e.g., retrofit with an IFR, 12-foot diameter tank, one of 
each of the various upgraded deck fittings), we determined that 
controlling this one storage vessel would have an annualized cost of 
approximately $5,550 per year and not be cost effective (i.e., over 
$1,000,000 per ton of HAP). We note that this information was available 
in the docket for commenters to use and provide their own estimates of 
HAP emissions and costs for control for this storage vessel. When 
considering this information, we find the option to tighten the 
capacity and MTVP thresholds to be even less cost effective if you 
consider impacts requiring control from the 58 m\3\ storage vessel. 
Thus, as previously discussed, we are not finalizing the proposed 
capacity and MTVP thresholds we proposed for storage vessels and are 
keeping the current MACT level of control for storage vessels in place.
    Comment: We received comments in support of and against the 
proposal to require use of the Modified El Paso Method for repairing 
leaks in heat exchange systems. A commenter that supported the proposal 
noted that at least eight facilities in the source category were 
already using the Modified El Paso Method. On the other hand, some 
commenters said the EPA's proposed control requirements for heat

[[Page 40397]]

exchange systems were not cost effective when considering the actual 
costs to repair leaks. A commenter said that the costs provided in 
Table 7 of the memorandum, Clean Air Act Section 112(d)(6) Technology 
Review for Heat Exchange Systems Located in the Ethylene Production 
Source Category, significantly underestimates the true cost associated 
with leak repair at ethylene production facilities. The commenter 
contended that for purposes of leak repair, after identifying a leak, 
maintenance and operations personnel must develop a strategy and 
schedule to remove the leaking exchanger from service, which involves 
identifying and selecting options for: Bypassing the process stream 
from the leaking system, the amount of production turndown necessary 
while the exchanger is out of service, identifying and selecting the 
appropriate contract personnel, and scheduling the work so that it does 
not conflict with any other planned maintenance. According to the 
commenter, several different personnel would be involved in these 
planning tasks including management, maintenance, production, and 
engineering staff (128 hour estimate is based on 32 hours x 4 persons). 
In addition to these planning costs, the commenter said that the EPA 
did not include costs for bypassing the leaking system to avoid a total 
shutdown which may include renting and plumbing temporary heat 
exchangers. The commenter also said that the EPA did not include costs 
for the rental and installation of cranes and scaffolding for accessing 
the heat exchanger for repairs, and costs for specialized contracted 
maintenance support to de-head the exchanger and perform the repair. 
Based on maintenance records, the commenter contended that repair costs 
range from $200,000 to $400,000 per event, not considering lost profit 
due to turndown or shutdown of the production unit. Factoring in these 
additional costs and using the EPA's estimated HAP emissions reductions 
of 25 tpy, the commenter said the revised cost effectiveness becomes 
$16,200 per ton of HAP. The commenter cited the RTR for Friction 
Materials Manufacturing Facilities (83 FR 19511, May 3, 2018) where the 
EPA found that $3,700 per ton for a permanent total enclosure was not 
cost effective, and the RTR for the Petroleum Refinery Sector (79 FR 
36916, June 30, 2014) where the EPA found that $14,100 per ton for 
lowering leak definitions was not cost effective. The commenter also 
said that in cases where the leaking heat exchanger must be completely 
replaced to fix the leak, the costs exceed $1 million. The commenter 
stated that the EPA acknowledged in the preamble that emissions from 
heat exchange systems have an overall small contribution to cancer risk 
to the individual most exposed and that additional controls for heat 
exchange systems are not necessary to provide an ample margin of 
safety.
    Response: We disagree with commenters that said the proposed 
requirements for heat exchange systems to use the Modified El Paso 
Method and a leak definition of 6.2 ppmv of total strippable 
hydrocarbon concentration (as methane) in the stripping gas are not 
cost-effective. We are finalizing this proposed development under CAA 
section 112(d)(6) with some minor technical clarifications that are 
discussed elsewhere in the rulemaking record (see our response in this 
preamble to commenters' requests to include an alternative mass-based 
leak definition; also see the document, Summary of Public Comments and 
Responses for the Risk and Technology Review for Ethylene Production, 
which is available in Docket ID No. EPA-HQ-OAR-2017-0357). We note that 
the existing MACT standards that were finalized in 2002 (67 FR 46258, 
July 12, 2002) contained LDAR provisions and many of the items 
commenters include in their cost estimates are associated with repair 
costs that would have already been incurred under the existing MACT 
standards. These repair costs include, but are not limited to, 
planning, bypassing, various equipment rental costs, costs for 
scaffolding, and deheading. We also disagree with commenter's cost 
estimates because most of the items that they claim are associated with 
the proposed revision will not be required by this final rule 
requirement (i.e., we determined that the costs associated with the 
difference between conducting leak sampling using water sampling 
methods and leak sampling using the Modified El Paso Method as well as 
costs associated with combined operator and maintenance labor to find 
and repair a leak by plugging are the only costs that would be 
additionally incurred by the technology review standards). Further, 
commenters failed to provide enough information demonstrating why their 
costs information represents leak repair costs for an average heat 
exchange system at an ethylene production facility. For example, 
facilities may have additional heat exchange system capacity available 
at their facility and may opt to use this capacity to repair the leak, 
at no additional expense, yet this was not considered by commenters. 
Also, commenters did not provide additional information for us to 
evaluate the percentage of time additional leaks would have to be fixed 
under the revised heat exchange system standards proposed under 
technology review compared to the original MACT standards. Thus, we 
continue to believe that the majority, if not all of the repair costs 
cited by commenters would have been accounted for and incurred as a 
result of the existing MACT standards and that simply plugging a 
leaking heat exchanger would more likely represent the average cost 
additionally incurred by ethylene production sources as a result of 
this technology review development. In addition, in the proposed rule 
we explained that we considered a heat exchanger to effectively be at 
the end of its useful life if it was leaking to such an extent that it 
would need to be replaced in order to comply with the requirement; so 
the cost of replacing the heat exchanger would be an operational cost 
that would be incurred by the facility as a result of routine 
maintenance and equipment replacement and not attributable to the 
proposed work practice standard that is being finalized in this action 
(see the technical memorandum, Clean Air Act Section 112(d)(6) 
Technology Review for Heat Exchange Systems in the Ethylene Production 
Source Category, which is available in Docket ID No. EPA-HQ-OAR-2017-
0357). Thus, given all of this information, we continue to believe that 
those costs associated with the difference between conducting leak 
sampling using water sampling methods and leak sampling using the 
Modified El Paso Method as well as costs associated with combined 
operator and maintenance labor to find and repair a leak by plugging 
are the only costs that would be additionally incurred by the 
technology review standards. Based on our analysis, we find that the 
revised standards we proposed for heat exchange systems are cost 
effective at $1,060 per ton of HAP without consideration of product 
recovery and result in a cost savings when you consider product 
recovery. Therefore, we are finalizing the revisions for heat exchange 
systems that we proposed under CAA section 112(d)(6) with some minor 
technical clarifications that are discussed elsewhere in this preamble 
and in the document, Summary of Public Comments and Responses for the 
Risk and Technology Review for Ethylene Production, which is available 
in Docket ID No. EPA-HQ-OAR-2017-0357.
    Additionally, with respect to rules where we have determined that

[[Page 40398]]

requirements are not cost effective at varying levels of cost 
effectiveness, we note that there can be other compelling factors 
beyond cost effectiveness that play a role in the EPA's determinations 
and that each rulemaking is unique and should be judged on its own 
merits. With respect to the two proposed rules commenters cited, we 
note that different determinations likely would have resulted if some 
of the other variables in those rulemaking records were not considered, 
such as for the Friction Materials RTR (83 FR 19511, May 3, 2018) where 
no facilities in the source category would have been impacted by rule 
revisions under the technology review due to process changes and use of 
non-HAP solvents. Similarly, for the Petroleum Refinery RTR (79 FR 
36916, June 30, 2014), consideration of other fugitive emissions 
management techniques that were finalized (e.g., fenceline monitoring) 
also had the potential to help control equipment leaks in the Petroleum 
Refinery source category. Regardless, and as stated above, we believe 
that the developments we identified for heat exchange systems used in 
the Ethylene Production source category are cost effective and are 
finalizing these revisions under CAA section 112(d)(6).
    Comment: Some commenters recommended the EPA revise 40 CFR 
63.1086(e)(i) through (iii) to include an alternative mass-based leak 
definition. Commenters argued that by only defining a leak on a 
concentration basis, smaller facilities with lower heat exchange system 
recirculation rates would be forced to identify and fix leaks with a 
much lower potential HAP emissions rate than facilities with larger 
recirculation systems.
    A commenter said the EPA should calculate the equivalent mass-based 
emission rate using the 90th percentile heat exchange system 
recirculation rates (165,000 gpm) and the leak definition of 6.2 ppmv 
as methane in the stripping gas, assuming 100 percent of the 
hydrocarbon is hexane, for an equivalent mass leak-based leak 
definition of 6.1 pounds per hour (2.8 kilograms per hour) of Table 1 
to 40 CFR part 63, subpart XX HAP.
    Another commenter said the EPA should modify the leak action level 
to be defined as potential strippable hydrocarbon emissions greater 
than 4.0 pounds per hour for heat exchange systems with a recirculation 
flowrate less than or equal to 100,000 gpm. The commenter asserted that 
the memorandum, CAA Section 112(d)(6) Technology Review for Heat 
Exchangers Located in the Ethylene Production Source Category, mentions 
one case where the concentration of methane was 6.1 ppmv in the gas 
phase and just less than 80 parts per billion by weight (ppbw) in the 
water phase, thus, resulting in emissions of 0.64 pounds per hour based 
on a recirculation rate of 17,000 gpm. Using this information, the 
commenter determined that an average cooling water system with a 
recirculation rate of 100,000 gpm (the average cooling water 
recirculation rate of the ethylene production industry based on the 
responses the EPA received to the CAA section 114 ICR) and a 
concentration of strippable hydrocarbons in the water of 80 ppbw, will 
have potential strippable hydrocarbon emissions of 4 pounds per hour.
    A commenter also recommended the EPA adjust the ``delay of repair'' 
leak action level in 40 CFR 63.1088(d)(3) to 40 pounds per hour of 
potential strippable hydrocarbon emissions for heat exchange systems 
with a recirculation rate of 100,000 gpm or less, and maintain the 
``delay of repair'' action level at a total strippable hydrocarbon 
concentration (as methane) in the stripping gas of 62 ppmv 
(approximately 800 ppbw in the cooling water) for heat exchange systems 
with a recirculation rate greater than 100,000 gpm.
    Response: We agree with commenters that an alternative mass-based 
leak action level is warranted, and that by not finalizing such an 
alternative, smaller heat exchange systems with low recirculation rates 
would be disproportionally affected and forced to repair leaks with a 
much lower potential HAP emissions rate than facilities with larger 
recirculation rate systems. We disagree with commenters, however, that 
the foundation of the alternative mass-based leak action level should 
be based on the average recirculation rate in the source category of 
100,000 gpm or the 90th percentile heat exchange system recirculation 
rate of 165,000 gpm. As commenters allude to, the goal of this 
alternative is to not disproportionally impact small heat exchange 
systems with low emissions potential. To that end and given that this 
is a technology review under CAA section 112(d)(6), consideration of 
where it is cost-effective to repair a leaking heat exchange system 
should be a primary consideration for this alternative. In our 
technology review memorandum, Clean Air Act Section 112(d)(6) 
Technology Review for Heat Exchange Systems Located in the Ethylene 
Production Source Category, at Docket ID Item No. EPA-HQ-OAR-2017-0357-
0011, the nationwide impacts and emissions reductions presented in 
Tables 15 and 16 are used to determine the HAP cost effectiveness for 
the source category on average. In other words, the nationwide impacts 
for HAP cost effectiveness (without consideration of product recovery) 
at $1,060/ton of HAP would be the HAP cost effectiveness for an average 
heat exchange system in the source category that has a recirculation 
rate of approximately 100,000 gpm. We also generally consider that 
technology review developments are not cost effective for organic HAP 
if the cost effectiveness is more than $10,000/ton (or approximately 10 
times higher than the cost effectiveness estimated for the average heat 
exchange system at ethylene production sources). Since the 
recirculation rate directly correlates to mass emissions potential at 
the same leak concentration, the mass emissions for a heat exchange 
system with recirculation rate of 10,000 gpm or less would be at least 
10 times smaller compared to a 100,000 gpm recirculation rate system 
and the annual costs to find and repair leaks would not change. As 
such, we determined that it is not cost effective to control leaks at 
the leak action level of total strippable hydrocarbon of 6.2 ppmv (as 
methane) for heat exchange systems with a recirculation rate of 10,000 
gpm or less, because the HAP cost effectiveness would be approximately 
$10,000/ton of HAP or more. Therefore, to alleviate the concern about 
disproportionally impacting small heat exchange systems with low HAP 
emissions potential, and to ensure our technology review developments 
are cost effective for all heat exchange systems in the source 
category, we are finalizing an alternative total hydrocarbon mass-based 
emissions rate leak action level (as methane) of 0.18 kilograms per 
hour (0.4 pounds per hour) for heat exchange systems in the Ethylene 
Production source category that have a recirculation rate of 10,000 gpm 
or less. We also agree that for consistency, and to not 
disproportionately impact small heat exchange systems, that an 
alternative mass-based leak action level of 1.8 kilograms per hour (4.0 
pounds per hour) for delay of repair for heat exchange systems with a 
recirculation rate of 10,000 gpm or less is warranted.
4. What is the rationale for our final approach for the technology 
review?
    Our technology review focused on the identification and evaluation 
of developments in practices, processes, and control technologies that 
have occurred since the EMACT standards were originally promulgated on 
July 12, 2002 (67 FR 46258). Specifically, we

[[Page 40399]]

focused our technology review on all existing MACT standards for the 
various emission sources in the Ethylene Production source category, 
including, storage vessels, ethylene process vents, transfer racks, 
equipment leaks, waste streams, and heat exchange systems. In the 
proposal, we only identified cost-effective developments for storage 
vessels and heat exchange systems and proposed to tighten the standards 
for these two emissions sources under technology review. We did not 
identify developments in practices, processes, or control technologies 
for ethylene process vents, transfer racks, equipment leaks, and waste 
streams. Further rationale about the technology review can be found in 
the proposed rule (84 FR 54278, October 9, 2019) and in the supporting 
materials in the rulemaking docket at Docket ID No. EPA-HQ-OAR-2017-
0357.
    During the public comment period, we received several comments on 
our proposed determinations for the technology review. The comments and 
our specific responses and rationale for our final decisions can be 
found in section IV.B.3 of this preamble and in the document, Summary 
of Public Comments and Responses for the Risk and Technology Reviews 
for the Ethylene Production Source Category, available in the docket 
for this action. No information presented by commenters has led us to 
change our proposed determination, under CAA section 112(d)(6) for 
ethylene process vents, transfer racks, equipment leaks, and waste 
streams, and we are finalizing our determination that no changes to 
these standards are warranted. Substantive information was submitted by 
commenters on proposed revisions for heat exchange systems, and based 
on this information, we are finalizing revisions for heat exchange 
systems and making some technical clarifications to allow compliance 
with an alternative mass-based leak action level for small heat 
exchange systems with a recirculation rate of 10,000 gpm or less in 
lieu of the concentration-based leak action level that was proposed. 
Lastly, for storage vessels, substantive information was also submitted 
by commenters, and based on this additional information, we find that 
the developments we proposed are not cost effective for this emissions 
source. Thus, we are not finalizing any changes for storage vessels as 
a result of the technology review.

C. Amendments Pursuant to CAA Section 112(d)(2) and (d)(3) for the 
Ethylene Production Source Category

1. What did we propose pursuant to CAA section 112(d)(2) and (3) for 
the Ethylene Production source category?
    Under CAA section 112(d)(2) and (3) we proposed to amend the 
operating and monitoring requirements for flares used as APCDs in the 
Ethylene Production source category to ensure that facilities that use 
flares as APCDs meet the EMACT standards at all times when controlling 
HAP emissions. We proposed to add a provision, 40 CFR 63.1103(e)(4), to 
extend the application of the Petroleum Refinery Flare Rule 
requirements in 40 CFR part 63, subpart CC to flares in the Ethylene 
Production source category with clarifications, including, but not 
limited to, specifying that several definitions in 40 CFR part 63, 
subpart CC, that apply to petroleum refinery flares also apply to 
flares in the Ethylene Production source category, adding a definition 
and requirements for pressure-assisted multi-point flares, and 
specifying additional requirements when a gas chromatograph or mass 
spectrometer is used for compositional analysis. Specifically, we 
proposed to retain the General Provisions requirements of 40 CFR 
63.11(b) and 40 CFR 60.18(b) that flares used as APCDs in the Ethylene 
Production source category operate pilot flame systems continuously and 
that flares operate with no visible emissions (except for periods not 
to exceed a total of 5 minutes during any 2 consecutive hours) when the 
flare vent gas flow rate is below the smokeless capacity of the flare. 
We also proposed to consolidate measures related to flare tip velocity 
and new operational and monitoring requirements related to the 
combustion zone gas. Further, in keeping with the elimination of the 
SSM exemption, we proposed a work practice standard related to the 
visible emissions and velocity limits during periods when the flare is 
operated above its smokeless capacity (e.g., periods of emergency 
flaring). We proposed eliminating the cross-references to the General 
Provisions and instead to specify all operational and monitoring 
requirements that are intended to apply to flares used as APCDs in the 
Ethylene Production source category.
    In addition, we proposed provisions and clarifications for periods 
of SSM and bypasses, including PRD releases, bypass lines on closed 
vent systems, in situ sampling systems, maintenance activities, and 
certain gaseous streams routed to a fuel gas system to ensure that CAA 
section 112 standards apply continuously, consistent with Sierra Club 
v. EPA 551 F. 3d 1019 (D.C. Cir. 2008). For PRD releases, we proposed 
at 40 CFR 63.1103(e)(2) definitions of ``pressure relief device'' and 
``relief valve'' and proposed to add a work practice standard at 40 CFR 
63.1107(h)(3), (6), and (7) for PRDs that vent to atmosphere that 
requires three prevention measures and root cause analysis and 
corrective action when a release occurs.\4\ We proposed to require that 
sources monitor PRDs that vent to the atmosphere using a system that is 
capable of identifying and recording the time and duration of each 
pressure release and of notifying operators that a pressure release has 
occurred. We also proposed to add a provision, 40 CFR 63.1107(h)(4), to 
require PRDs that vent through a closed vent system to a control device 
or to a process, fuel gas system, or drain system meet minimum 
requirements for the applicable control system. In addition, we 
proposed to add a provision, 40 CFR 63.1107(h)(5), to exclude the 
following types of PRDs from the work practice standard for PRDs that 
vent to the atmosphere: (1) PRDs with a design release pressure of less 
than 2.5 pounds per square inch gauge (psig); (2) PRDs in heavy liquid 
service; (3) PRDs that are designed solely to release due to liquid 
thermal expansion; and (4) pilot-operated and balanced bellows PRDs if 
the primary release valve associated with the PRD is vented through a 
control system. Finally, we proposed to add a provision, 40 CFR 
63.1107(h)(8), to require future installation and operation of non-
flowing pilot-operated PRDs at all affected sources.
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    \4\ Examples of prevention measures include flow indicators, 
level indicators, temperature indicators, pressure indicators, 
routine inspection and maintenance programs or operator training, 
inherently safer designs or safety instrumentation systems, deluge 
systems, and staged relief systems where the initial PRD discharges 
to a control system.
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    For bypass lines on closed vent systems, we proposed to add a 
provision, 40 CFR 63.1103(e)(6), to not allow an owner or operator to 
bypass the APCD at any time, and if a bypass is used, then the owner or 
operator is to estimate and report the quantity of organic HAP 
released. We proposed this revision to be consistent with Sierra Club 
v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), where the Court determined that 
standards under CAA section 112(d) must provide for compliance at all 
times, because bypassing an APCD could result in a release of regulated 
organic HAP to the atmosphere. We also proposed that the use of a cap, 
blind flange, plug, or second valve on an

[[Page 40400]]

open-ended valve or line is sufficient to prevent a bypass. For in situ 
sampling systems, we proposed to delete the exclusion of ``in situ 
sampling systems (online analyzers)'' from the definition of ``ethylene 
process vent'' and require that these kinds of vents meet the standards 
applicable to ethylene process vents at all times.
    For maintenance activities, we proposed a definition for 
``periodically discharged'' and removed ``episodic or nonroutine 
releases'' from the list of vents not considered ethylene process 
vents. We proposed to add a work practice standard at 40 CFR 
63.1103(e)(5) requiring that, prior to opening process equipment to the 
atmosphere, the equipment either: (1) Be drained and purged to a closed 
system so that the hydrocarbon content is less than or equal to 10 
percent of the lower explosive limit (LEL); (2) be opened and vented to 
the atmosphere only if the 10-percent LEL cannot be demonstrated and 
the pressure is less than or equal to 5 psig, provided there is no 
active purging of the equipment to the atmosphere until the LEL 
criterion is met; (3) be opened when there is less than 50 pounds of 
VOC that may be emitted to the atmosphere; or (4) for installing or 
removing an equipment blind, depressurize the equipment to 2 psig or 
less and maintain pressure of the equipment where purge gas enters the 
equipment at or below 2 psig during the blind flange installation, 
provided none of the other proposed work practice standards can be met. 
For cases where an emission source is required to be controlled in the 
EMACT standards but is routed to a fuel gas system, we proposed to add 
footnote b to Table 7 of 40 CFR 63.1103(e) to require that any flare, 
utilizing fuel gas whereby the majority (i.e., 50 percent or more) of 
the fuel gas in the fuel gas system is derived from an ethylene 
production unit, comply with the proposed flare operating and 
monitoring requirements.
    We proposed to add work practice standards at 40 CFR 63.1103(e)(7) 
and (8) to address the decoking of ethylene cracking furnaces (i.e., 
the coke combustion activities in an ethylene cracking furnace), which 
is defined as a shutdown activity and was previously only required to 
minimize emissions by following a startup, shutdown, malfunction plan. 
This ensures that CAA section 112 standards apply continuously. To 
minimize coke combustion emissions from the decoking of the radiant 
tube(s) in each ethylene cracking furnace, we proposed that an owner or 
operator must conduct daily inspections of the firebox burners and 
repair all burners that are impinging on the radiant tube(s) as soon as 
practical, but not later than 1 calendar day after the flame 
impingement is found. We also proposed that an owner or operator 
conduct two of the following activities: (1) Continuously monitor (or 
use a gas detection tube every hour to monitor) the CO2 
concentration at the radiant tube(s) outlet for indication that the 
coke combustion in the ethylene cracking furnace radiant tube(s) is 
complete; (2) continuously monitor the temperature at the radiant 
tube(s) outlet to ensure the coke combustion occurring inside the 
radiant tube(s) is not so aggressive (i.e., too hot) that it damages 
either the radiant tube(s) or ethylene cracking furnace isolation 
valve(s); (3) after decoking, but before returning the ethylene 
cracking furnace back to normal operations, purge the radiant tube(s) 
with steam and verify that all air is removed; or (4) after decoking, 
but before returning the ethylene cracking furnace back to normal 
operations, apply a coating material to the interior of the radiant 
tube(s) to protect against coke formation inside the radiant tube 
during normal operation. In addition, we proposed that the owner or 
operator must conduct the following inspections for ethylene cracking 
furnace isolation valve(s): (1) Prior to decoking operation, inspect 
the applicable ethylene cracking furnace isolation valve(s) to confirm 
that the radiant tube(s) being decoked is completely isolated from the 
ethylene production process so that no emissions generated from 
decoking operations are sent to the ethylene production process; and 
(2) prior to returning the ethylene cracking furnace to normal 
operations after a decoking operation, inspect the applicable ethylene 
cracking furnace isolation valve(s) to confirm that the radiant tube(s) 
that was decoked is completely isolated from the decoking pot or 
furnace firebox such that no emissions are sent from the radiant 
tube(s) to the decoking pot or furnace firebox once the ethylene 
cracking furnace returns to normal operation.
    More information concerning our proposal to address CAA section 
112(d)(2) and (3) can be found in the proposed rule (84 FR 54278, 
October 9, 2019).
2. How did the revisions pursuant to CAA section 112(d)(2) and (3) 
change since proposal?
    The EPA is finalizing the revisions to the monitoring and 
operational requirements for flares, as proposed, except that we are 
not finalizing the work practice standard for velocity exceedances for 
flares operating above their smokeless capacity. In response to 
comments that owners or operators have historically considered 
degassing emissions from shutdown of storage vessels to be covered by 
their SSM plans per 40 CFR 63.1108(a)(5) and relied on the language in 
40 CFR 63.1108(a)(5) that back-up control devices are not required, we 
are adding a separate standard for storage vessel degassing for storage 
vessels subject to the control requirements in Table 7 to 40 CFR 
63.1103(e)(3)(b) and (c). The standard requires owners or operators to 
control degassing emissions for floating roof and fixed roof storage 
vessels until the vapor space concentration is less than 10 percent of 
the LEL. Storage vessels may be vented to the atmosphere once the 
storage vessel degassing concentration threshold is met (i.e., 10 
percent LEL) and all standing liquid has been removed from the vessel 
to the extent practical.
    Lastly, based on comments received on the proposal, we are making 
some minor editorial corrections and technical clarifications to the 
work practice standards for the decoking of ethylene cracking furnaces. 
Specifically, we are adding delay of repair provisions to the flame 
impingement inspection requirements, adding clarifying text to the 
CO2 monitoring, coil outlet temperature monitoring, air 
removal, and radiant tube(s) treatment requirements, and removing 
unnecessary recordkeeping associated with the time each isolation valve 
inspection is performed and the results of that inspection even if poor 
isolation was not found. For details about these minor changes, refer 
to Section 6.7 of the document, Summary of Public Comments and 
Responses for the Risk and Technology Reviews for the Ethylene 
Production Source Category, available in the docket for this action.
3. What key comments did we receive on the proposal revisions pursuant 
to CAA section 112(d)(2) and (3), and what are our responses?
    This section provides comment and responses for the key comments 
received regarding our proposed revisions for flares and clarifications 
for periods of SSM, including PRD releases, decoking operations for 
ethylene cracking furnaces (i.e., the decoking of ethylene cracking 
furnace radiant tubes), and storage vessel emptying and degassing. 
Other comment summaries and the EPA's responses for additional issues 
raised regarding these activities as well as issues raised regarding 
our proposed revisions for bypass lines on closed vent systems, in situ 
sampling systems, maintenance activities, and certain gaseous streams 
routed to a fuel gas system, can be found in the

[[Page 40401]]

document, Summary of Public Comments and Responses for the Risk and 
Technology Reviews for the Ethylene Production Source Category, 
available in the docket for this action.
    Comment: We received comments in support of and against our 
proposal to establish similar requirements for flares used in the 
Ethylene Production source category as the flare requirements 
established in the 2015 Petroleum Refinery NESHAP, including the 
incorporation of the net heating value of the combustion zone (NHVcz) 
calculation and limits. One commenter supported the proposed 
strengthened operational and monitoring requirements, which the 
commenter stated reflect best practices already in place at many 
facilities and must be required pursuant to CAA sections 112(d)(2), 
(3), and (6). The commenter reiterated the EPA's determination that 
measuring the net heating value of the flare gas, as it enters the 
flares, is insufficient to determine combustibility because facilities 
add steam and other gases not accounted for and that flare performance 
data shows that the net heating value of vent gas in the combustion 
zone must reach at least 270 British thermal units per standard cubic 
foot (Btu/scf). Some commenters also supported the EPA's proposal 
``that owners or operators may use a corrected heat content of 1,212 
Btu/scf for hydrogen, instead of 274 Btu/scf, to demonstrate compliance 
with the NHVcz operating limit,'' because the data show that the 
control efficiency of a flare drops off significantly below this level.
    Another commenter also suggested other improvements to the proposed 
flared revisions. According to this commenter, data shows the proposed 
rule does not assure heating values in the combustion zone that are 
high enough to achieve the EMACT standards. The commenter said that the 
EPA has an extensive record to support its conclusion that some 
ethylene production facility flares do not destroy at least 98 percent 
of HAP, and urged the EPA to mandate additional measures to ensure 98-
percent flare destruction efficiency. The commenter noted that at least 
one operator, Formosa, recognizes that flares can achieve 99-percent 
reduction in HAP emissions for small molecules.\5\ The commenter stated 
that continuous monitoring of either the net heating value or 
composition of flare gas must be required pursuant to CAA sections 
112(d)(2), (3), and (6). The commenter recommended that the EPA also 
consider the following measures to help assure compliance with 98-
percent destruction efficiency:
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    \5\ The commenter provided the following reference: RISE St. 
James et al. Comments on 14 Proposed Initial Title V/Part 70 Air 
Permits, Proposed Initial Prevention of Significant Deterioration 
Permit, and the Associated Environmental Assessment Statement for FG 
LA, LLC (Formosa) Chemical Complex, Attachment E at 18 (August 12, 
2019).
---------------------------------------------------------------------------

     Prohibit wake dominated flow flaring conditions. The 
commenter noted that studies have shown that high winds can decrease 
flare destruction efficiency.\6\
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    \6\ The commenter provided the following reference: Robert E. 
Levy et al., Indus. Prof. for Clean Air, Reducing Emissions from 
Plant Flares (No. 61) at 1 (April 24, 2006).
---------------------------------------------------------------------------

     Require continuous video monitoring and recording for 
flares equipped with video monitoring and flares that vent more than 1 
million standard cubic feet scf per day (MMscf/day).\7\
---------------------------------------------------------------------------

    \7\ The commenter provided the following reference: See 84 FR 
54296; BAAQMD Sec.  12-11-507: requiring continuous video monitoring 
and recording for flares equipped with video monitoring and flares 
with vent gas more than 1 MMscf/day); SCAQMD Rule 1118(g)(7): 
requiring continuous video monitoring and recording; Consent Decree, 
United States of America v. Marathon Petroleum Company LP et al., 
No. 12-cv-11544 (E.D. Mich.) (April 5, 2012); Consent Decree, United 
States of America et al. v. BP Products North America Inc., No. 12-
cv-0207 (N.D. Ind.) (May 23, 2012); Consent Decree, United States of 
America v. Shell Oil Company et al., No. 13-cv-2009 (S.D. Tex.) 
(July 10, 2013); Consent Decree, United States of America v. Flint 
Hills Resources Port Arthur, LLC, No. 14-cv-0169, at 12 (E.D. Tex.) 
(March 20, 2014).
---------------------------------------------------------------------------

     Require monitoring of pilot gas, which is already required 
by the South Coast Air Quality Management District (SCAQMD) and Bay 
Area Air Quality Management District (BAAQMD).
    The commenter also stated that the EPA should require that 
facilities conduct necessary flare maintenance and upgrades and have 
additional flare capacity on standby. The commenter stated that if a 
flare is smoking, that may mean it simply needs to be either maintained 
or updated to address the problem. The commenter recommended add-on 
equipment to augment the smokeless capacity of a flare.\8\ The 
commenter also said that the EPA neither explained why other types of 
conveyances are not possible, nor can the EPA justify a standard that 
exempts equipment routed to a flare from the standards that generally 
apply to such equipment.
---------------------------------------------------------------------------

    \8\ The commenter provided the following reference: John Zink 
Hamworthy, Smokeless, Safe, Economical Solutions: Refining & 
Petrochemical Flares. Pg. 4 (this technology can increase the 
smokeless capacity of a flare by nearly 38 percent), available at 
https://www.johnzink.com/wp-content/uploads/Flares-Refining-Petrochemical.pdf.
---------------------------------------------------------------------------

    Response: We appreciate the support from several commenters for the 
flare operational and monitoring requirements being finalized at 40 CFR 
63.1103(e)(4). However, we disagree with one commenter's request to 
mandate additional measures to ensure 98-percent flare combustion 
efficiency. The flare requirements we are finalizing are already 
designed to ensure flares meet a minimum destruction efficiency of 98 
percent, consistent with the MACT control requirements.
    We disagree with the commenter's specific request to prohibit wake 
dominated flow flaring conditions as we have extremely limited data to 
suggest that wind adversely impacts the combustion efficiency of 
flares, let alone the combustion efficiency of industrial-sized flares 
used at ethylene production units. Commenters submitted no new data to 
otherwise support the assertion that wind does indeed affect flare 
performance, and, as such, we are not persuaded into changing our 
position at proposal that no flare operating parameter(s) are needed to 
minimize wind effects on flare performance.
    We disagree with the commenter's specific request to require 
continuous video monitoring and recording for flares equipped with 
video monitoring and flares that vent more than 1 MMscf/day. We note 
that in the final rule we have provided for the use of video camera 
surveillance monitoring as an alternative to EPA Method 22 monitoring. 
Observation via the video camera feed can be conducted readily 
throughout the day and will allow the operators of the flare to watch 
for visible emissions at the same time they are adjusting the flare 
operations.
    We also disagree with the commenter's specific request to require 
monitoring of pilot gas. The data available to us suggests that heat 
release from the flare pilots are generally negligible when regulated 
materials are sent to the flare and exclusion of the flare pilot gas 
simplifies the NHVcz calculation. Even when only purge gas is used, the 
flare pilots typically only provided about 10 percent of the total heat 
input to the flare and typically well less than 1 percent in the recent 
passive fourier transform infrared spectrometry flare tests when 
potential regulated material is routed to the flare (this is dependent 
on the size of the flare, number of pilots, and flare tip design, which 
impacts minimum purge flows). We are finalizing the definition of flare 
vent gas as proposed, which excludes pilot gas.
    Also, we disagree with the commenter's specific request to require 
additional flare capacity on standby to avoid a smoking flare because 
it would require new additional flares to operate at idle conditions 
for the vast majority

[[Page 40402]]

of time, contributing to additional criteria pollutant emissions on a 
continuous basis, while having only a small impact on HAP emissions. 
For example, an existing flare burns approximately 25,000 to 100,000 
standard cubic feet per day of natural gas (or fuel gas). If three new 
flares are added for each existing flare to ensure flares do not smoke 
during emergency shutdowns or other similar major events, then the 
additional emissions per existing flare would be 1,000 to 4,100 
megagrams per year of CO2 equivalence and 0.9 to 3.6 tpy of 
nitrogen oxides. This estimate does not include emissions from the 
generation of the extra steam needed for these flares to operate in a 
smokeless manner during the emission events. Therefore, the secondary 
impacts associated with having greater smokeless flare capacity would 
be significant. In addition, it is not clear whether the specific 
technology that the commenter cited to augment the smokeless capacity 
of a flare (i.e., a specific steam-assisted flare system that uses 
multiple-port supersonic nozzle technology) is an ``add-on'' 
technology, nor did the commenter provide any data to quantify or 
substantiate the claims, or any other additional details on costs or 
emissions reductions for it.
    Finally, the commenter did not provide any context regarding their 
comment about other types of conveyances and justifying standards; 
therefore, we are unable to respond to this portion of the comment.
    Comment: A commenter stated that the EPA improperly based the 
proposed flare revisions on CAA sections 112(d)(2) and (3) and should 
have evaluated them under CAA section 112(d)(6). The commenter stated 
that in setting the original MACT, the EPA did not have actual data 
demonstrating that the best performers were achieving 98-percent HAP 
reduction with flares (and other combustion devices), but rather based 
its conclusions on what it presumed sources would achieve if a 
combustion device were operated consistent with the requirements in the 
rule. The commenter further stated that the EPA is now claiming that 
98-percent HAP reduction was not achieved in practice by the best 
performers, and instead can only be achieved by the best performers if 
they take additional steps to reduce emissions (e.g., meet NHVcz 
requirements and implement additional monitoring). The commenter 
contended the proposed flare revisions can only be either a BTF 
standard or a revision as a result of the technology review, and the 
EPA cannot make the standard more stringent simply by claiming it is 
ensuring compliance with the current standard.
    The commenter argued the EPA should have evaluated the flare 
revisions under CAA section 112 (d)(6), found the revisions were not 
cost effective, and not proposed the flare revisions. To support the 
commenter's contention that the proposed flare requirements would not 
be cost effective, the commenter provided updated estimates for the 
costs presented in Tables 3, 6, and 7 of the EPA memorandum, Control 
Option Impacts for Flares Located in the Ethylene Production Source 
Category. The commenter made the following statements regarding costs:
     The EPA did not consider the cost of constructing new 
flares at existing facilities to meet the proposed requirements. The 
commenter stated that they know that at least one company would be 
required under the proposed rule to install at least two new flares, 
due to the high potential for existing flares to exceed the number of 
visible emissions events allowed, with a capital cost of $20 million 
and annualized costs of $3.1 million.
     Gas chromatographs would need to be installed in certain 
instances to comply with the proposed monitoring requirements, which 
the commenter suggests would have an estimated nationwide capital 
investment of $964,000 and annualized costs of $140,000 for 
installation and operation.
     The EPA did not account for the costs associated with 
upgrading natural gas controls and flow monitoring; the commenter 
estimated approximately 47 flares will require upgraded supplemental 
fuel controls and monitoring equating to a nationwide capital 
investment of $5.3 million and an annualized cost of approximately $1 
million.
     The EPA did not account for supplemental natural gas 
firing to meet the revised NHVcz operating parameter, which the 
commenter estimates would cost approximately $66.8 million per year in 
additional operating costs.
     The EPA underestimated the costs to develop the flare 
management plan by inappropriately relying on the cost estimated for 
refineries. However, most refineries were subject to similar flare 
management plan requirements under 40 CFR part 60, subpart Ja, and, 
therefore, were only required to update existing plans, whereas the 
commenter said ethylene producers will generally be required to develop 
new flare management plans. The commenter estimated the cost to develop 
a new flare management plan is $23,300 per flare.
     The EPA did not include the cost to develop the continuous 
parametric monitoring system monitoring plan required by 40 CFR 
63.671(b), which they estimate is an additional $7,400 per flare to 
develop.
    Using their updated costs and the EPA's estimated 1,430 tpy of HAP 
reductions, the commenter stated that the cost effectiveness of the 
proposed flare requirements would be $55,874 per ton of HAP reduced. 
The commenter argued that the EPA would have found the proposed flare 
revisions not cost effective under CAA section 112(d)(6) and, 
therefore, would not have included the changes in the proposed rule.
    Another commenter stated there would be complications complying 
with the proposed flare revisions, which would further increase the 
cost of the proposal, including: (1) When gas chromatographs are 
currently in use, some flares will need to add calorimeters to directly 
measure the net heating value on a minute-by-minute basis to help with 
process control and meet the requirements on a 15-minute basis; (2) 
some flares have multiple vent gas lines entering the flare system 
(e.g., a line to the base of the flare and a line entering the side of 
the flare stack) and additional vent gas monitors will be needed; (3) 
some flares have two or more steam lines to the flare tip and 
additional steam flow monitors will be needed; and (4) some flares will 
need to install larger volume supplemental fuel lines, triggering the 
need for permitting and construction of these systems.
    Response: We disagree with the commenter that the flare revisions 
should have been evaluated and proposed under CAA section 112(d)(6). As 
explained at proposal, we are not revising the MACT standards, which 
generally require 98-percent control efficiency and allow an owner or 
operator to choose the control device to meet the standard. Rather, we 
determined the flare operating and monitoring requirements were not 
adequate to ensure that 98-percent control efficiency can be met for a 
flare at all times. (84 FR 54294). As a general matter, available flare 
test data indicates that flares can achieve 99.9-percent control at 
certain times, and we believe that the long term nationwide average 
control efficiency achieved by flares meeting the final rule 
requirements could be over 98-percent control efficiency. In fact, in 
the development of the EMACT standards, the EPA stated that ``It is 
generally accepted that combustion devices achieve a 98 weight-percent 
reduction in HAP emissions . . .'' (65 FR 76428, December 6, 2000). 
However, in this

[[Page 40403]]

rulemaking, we are acknowledging that there are instances, particularly 
when either assist steam or assist air is used, where flare performance 
is degraded, and this level of control is not achieved at all times. 
Since the revisions ensure continuous compliance with the MACT 
standards, under CAA sections 112(d)(2) and (3), costs are not a factor 
considered for these revisions. NRDC v. EPA, 529 F.3d 1077, 1084 (D.C. 
Cir. 2008) (``EPA may not consider costs in setting the maximum 
achievable control technology `floors,' but only in determining whether 
to require `beyond the floor' reductions in emissions.''); NRDC v. EPA, 
489 F.3d 1364, 1376 (D.C. Cir. 2007 (``[C]ost is not a factor that EPA 
may permissibly consider in setting a MACT floor.''); see also, Nat'l 
Lime Ass'n v. EPA, 233 F.3d 625, 640 (D.C. Cir.2000)). At proposal, we 
acknowledged that some additional instrumentation and supplemental fuel 
may be needed for some flares and included cost estimates for these 
items. In addition, as previously explained, the EPA has no obligation 
to review prior MACT determinations and recalculate MACT floors as part 
of each CAA section112(d)(6) review. See, e.g., Nat'l Ass'n of Surface 
Finishing v. EPA, 795 F.3d 1 (D.C. Cir. 2015); Association of Battery 
Recyclers v. EPA, 716 F.3d 667, 673 (D.C. Cir. 2013), NRDC v. EPA, 529 
F.3d 1077(D.C. Cir. 2008).
    Contrary to the commenter's assertions, we did estimate costs in 
order to provide the resulting impacts of the proposed flare 
requirements, and we are not revising these costs as a result of this 
comment. The largest impact on annual costs is associated with 
supplemental natural gas to meet the NHVcz limit, which the commenter 
estimated is approximately 18 times higher than our estimate ($66.8 
million from the commenter versus $3.7 million for the EPA). We find 
the commenter's cost estimate unreasonable, and that commenters notably 
did not account for adjusting other flare parameters instead of using 
such a large amount of natural gas. We are also unable to re-create and 
establish how the estimated costs were developed by commenters due to a 
lack of information pertaining to baseline flare flows, waste gas 
compositions, current supplemental natural gas flows and steam flows. 
The commenter also stated that we did not include costs for flow 
monitors and controls, but these were specific items we included at 
proposal (see Table 3 in the memorandum, Control Option Impacts for 
Flares Located in the Ethylene Production Source Category), and the 
EPA's cost estimate for these items is higher than the commenter's cost 
estimate.
    Comment: We received comments in support of and against the 
proposed work practice requirements for visible emissions and flare tip 
velocity. A commenter contended that the inherent nature of the 
ethylene production process (i.e., ethylene production requires a 
significant amount of compression and refrigeration) necessitates the 
proposed flare work practice requirements to an even greater extent 
than the refinery sector. According to the commenter, in an upset 
situation such as a power outage or equipment malfunction, the 
compression and refrigeration systems can be lost resulting in a 
rapidly expanding volume of gas that must be removed from the process 
equipment to prevent potential damage and minimize safety risks.
    Several commenters objected to the EPA's proposed emergency flaring 
provisions for smoking flares. Some commenters stated that the proposed 
number of visible emissions exceedance events allowed is not supported 
by data the EPA received in response to the CAA section 114 ICR. A 
commenter said that the information the EPA used indicates that there 
were zero velocity exceedances during any smoking; however, 40 CFR 
63.670(o) implies that the flare must be operating above its smokeless 
capacity in order to smoke. The commenter said that unless the EPA has 
data indicating that these flares were exceeding their smokeless 
capacity (i.e., there was a tip velocity exceedance) at the time of the 
smoking event, the database that the EPA used does not support its 
claims on the frequency of these events at the best performing flares 
and the proposed deviation definitions at 40 CFR 63.670(o)(7)(ii) and 
(iv) are arbitrary and capricious. Similarly, a commenter noted that 
the EPA ``assumed . . . that the best performers would have no more 
than one [visible emissions] event every 7 years'' based on industry 
survey data provided by the American Chemistry Council (ACC), which the 
commenter noted fails to provide date ranges for the data presented, or 
to identify the location of the facilities. The commenter also noted 
that the survey identifies zero exceedances of the flare tip velocity 
from any facility, and the average presented by industry is provided 
without any context. The commenter warned that without access to more 
detailed underlying data it is impossible to determine if the ACC data 
includes smoking events that occurred at flares when the flow rate to 
the flare was also below the smokeless capacity of the flare. The 
commenter urged that smoking events that occur when the smokeless 
capacity of a flare is not exceeded should not be included in 
determining the average frequency of hydraulic load smoking events at 
flares.
    A commenter also stated that the information the ACC provided to 
the EPA showing visible emissions events and velocity exceedances (see 
Appendix B of Docket ID Item No. EPA-HQ-OAR-2017-0357-0017) identifies 
two flares as material handling flares and one flare as a process 
wastewater flare while all other flares are not characterized in any 
way. The commenter said that the inconsistent characterization of the 
flares raises questions about the nature of the flares used to support 
the EPA's claims on the frequency of these events at the best 
performing flares.
    In addition, the commenter reiterated that the proposed revisions 
for releases from smoking flares do not satisfy CAA section 112(d)(2) 
or (3). The commenter said the EPA did not provide rationale, and did 
not meet, the statutory test for smoking flares. The commenter also 
said the EPA did not provide a reasonable analysis or determination 
showing that allowing one to two uncontrolled such events every 3 
calendar years (plus force majeure event releases) reflects the average 
of the best performers' reductions and is the ``maximum achievable 
degree of emission reduction.'' The commenter urged that what is 
``achievable for the average'' is not the statutory test. The commenter 
expressed the view that it is unclear how a smoking flare could ever 
meet CAA sections 112(d)(2) and (3).
    The commenter recommended the EPA consider the data it collected on 
flares to determine the amount of HAP emitted. The commenter stated 
that the EPA has not explained why its own data on emission exceedances 
from equipment connected to flares would not allow it to set limits on 
smoking flares, and that the EPA has not and could not show, based on 
the record that the complete exemption for one to two smoking flare 
incidents at each flare, every 3 years, in any way satisfies CAA 
section 112(d)(3). The commenter stated that the EPA's failure to 
review actual data is especially egregious given the fact that the 
Texas Commission on Environmental Quality (TCEQ), the BAAQMD, and the 
SCAQMD have extensive data on the frequency that operators report 
smoking emissions from flares,\9\ and given that the

[[Page 40404]]

smokeless capacity of the flare is an easily ascertainable 
characteristic. The commenter argued that using this data, the EPA 
could have potentially determined a MACT floor that complies with the 
requirements of the CAA.
---------------------------------------------------------------------------

    \9\ The commenter provided the following reference: This data is 
available on TCEQ Emission Event Reporting website (https://www.tceq.texas.gov/field/eventreporting) and is also available in 
Excel format from the state agency.
---------------------------------------------------------------------------

    The commenter also warned that the EPA does not meet the BTF 
requirements in CAA section 112(d)(2). The commenter stressed that the 
EPA has not demonstrated that allowing multiple smoking flare 
exemptions from the standards is the ``maximum achievable degree of 
emission reduction'' from those flares. The commenter argued that, at 
the very least, the EPA must set standards on the duration and amount 
of gas that is routed to a flare during a malfunction event that causes 
the flare to operate above its smokeless capacity, in addition to the 
cap on the number of exemptions included in the proposed rule. The 
commenter stated that the HAP emission limits for flares during 
malfunctions cannot be less stringent than the emission limits that 
apply during normal operations.
    The commenter stated that, based on data from TCEQ, smoking flare 
events can last several minutes or multiple days, and the EPA's 
proposed regulations do not make clear whether this should be 
considered a single event or multiple smoking events. The commenter 
additionally noted that the EPA's proposed regulation does not make 
clear whether visible smoke emissions that are caused by multiple root 
causes occurring at the same time should count as one visible emission 
event or two.
    Response: First, as explained at proposal flares are used as APCDs 
to control HAP emissions in both the Petroleum Refinery and Ethylene 
Production source categories. It is therefore not a specific emission 
source within the EMACT standards and, thus, we did not seek to 
establish a MACT floor for flares at the time that we promulgated the 
EMACT standards in the GMACT NESHAP. Rather, we identified flares as an 
acceptable means for meeting otherwise applicable requirements and we 
established flare operational standards that we believed would achieve 
a 98-percent destruction efficiency on a continual basis. As previously 
explained, recognizing that flares were not achieving the 98-percent 
reduction efficiency in practice at all times, we proposed additional 
requirements in the October 9, 2019, proposed rule (84 FR 54294) to 
ensure that flares operate as intended at the time we promulgated the 
EMACT standards. This is entirely consistent with agency practice of 
fixing underlying defects in existing MACT standards under CAA sections 
112(d)(2) and (3), provisions that directly govern the initial 
promulgation of MACT standards. (See, National Emission Standards for 
Hazardous Air Pollutants from Petroleum Refineries, October 28, 2009, 
74 FR 55670; and National Emission Standards for Hazardous Air 
Pollutants: Group I Polymers and Resins; Marine Tank Vessel Loading 
Operations; Pharmaceuticals Production; and the Printing and Publishing 
Industry, April 21, 2011, 76 FR 22566)).
    Regarding the operational standards for flares operating above the 
smokeless capacity, we note that these flare emissions are due to a 
sudden increase in waste gas entering the flare, typically resulting 
from a malfunction or an emergency shutdown at one or more pieces of 
equipment that vents emissions to the flare. The EPA disagrees with 
commenter's suggestion that standards are warranted for the duration 
and amount of gas discharged to a flare during malfunction events, 
which are infrequent, unpredictable and not under the control of an 
operator. Flares are associated with a wide variety of process 
equipment and the emissions routed to a flare during a malfunction can 
vary widely based on the cause of the malfunction and the type of 
associated equipment. Thus, it is not feasible to establish a one-size-
fits-all standard on the amount of gas allowed to be routed to flares 
during a malfunction. Moreover, we note that routing emissions to the 
flare will result in less pollution than the alternative, which would 
be to emit directly to the atmosphere. We note that we do not set 
similar limits for thermal oxidizers, baghouses, or other control 
devices that we desire to remain operational during malfunction events 
to limit pollutant emissions to the extent practicable. However, we did 
propose work practice standards that we believed would be effective in 
reducing the size and duration of flaring events that exceed the 
smokeless capacity of the flare to improve overall flare performance. 
On that premise, we acknowledge that the data we received from ACC's 
survey identifies zero exceedances of the flare tip velocity during a 
smoking event; and we agree with the commenter that our proposed 
determination of the frequency of these events at the best performing 
sources is not supported. Therefore, in response to comments on our 
proposal, we are not finalizing the proposed work practice standard for 
when the flare vent gas flow rate exceeds the smokeless capacity of the 
flare and the tip velocity exceeds the maximum flare tip velocity 
operating limit. Instead, we are finalizing provisions that require 
compliance with the maximum flare tip velocity operating limit at all 
times, regardless of whether you are operating above the smokeless 
capacity of the flare.
    In order to ensure 98-percent destruction of HAP discharged to the 
flare (as contemplated at the time the EMACT standards were 
promulgated) during both normal operating conditions when the flare is 
used solely as a control device and malfunction releases where the 
flare acts both as a safety device and a control device, we are 
finalizing, as proposed, the work practice standard for when the flare 
vent gas flow rate exceeds the smokeless capacity of the flare and 
visible emissions are present from the flare for more than 5 minutes 
during any 2 consecutive hours during the release event. As described 
in more detail in our technical memorandum, Control Option Impacts for 
Flares Located in the Ethylene Production Source Category, located at 
Docket ID Item No. EPA-HQ-OAR-2017-0357-0017, the best performing flare 
in the Ethylene Production source category for which we have 
information on visible emissions has a visible emissions event once 
every 7 years. Even if the best-performing flare ``typically'' only has 
one event every 7 years, the fact that visible emissions events are 
random by nature (unpredictable, not under the direct control of the 
owner or operator) makes it difficult to use a short term time span to 
evaluate a backstop to ensure an effective work practice standard. 
Thus, when one considers a longer term time span of 20 years, our 
analysis shows that three events in 3 years would appear to be 
``achievable'' for the average of the best performing flares. We 
disagree with commenters that we should allow more or fewer visible 
emissions events above the smokeless capacity of a flare. We also 
disagree with commenters that the regulatory text we are cross-
referencing at 40 CFR 63.670(o) is unclear about what constitutes an 
event or how to handle multiple root causes, especially since there is 
generally only a singular root cause at the heart of a visible 
emissions event.
    With respect to the comment about conducting a BTF analysis under 
CAA section 112(d)(2), we note the work practice combustion efficiency 
standards (specifically limits on the net heating value in combustion 
zone)

[[Page 40405]]

apply at all times, including during periods of emergency flaring. 
Because flares are not an affected emissions source, but rather an 
APCD, no BTF analysis is needed. While requiring the use of systems 
such as back-up power or adding additional flares for additional flare 
capacity might alleviate additional visible emission events, we note 
that facilities would have to invest significant capital to build a 
back-up cogeneration power plant or add additional flare capacity for 
flares to operate on standby to handle very infrequent events we are 
limiting in this final rule. Combined with the costs, significant 
additional emissions would also be generated from a cogeneration power 
plant or from a flare operating in standby to handle infrequent smoking 
events and this would lead to a net environmental disbenefit and is 
contradictory to the commenter's own concerns about limiting emissions 
from flares since owners or operators of ethylene production facilities 
would have to construct more of them.
    Comment: A commenter noted that CAA section 112(h) allows the EPA 
to set a ``work practice standard'' in lieu of a numerical emission 
standard only if it is ``not feasible to prescribe or enforce an 
emission standard.'' Further, the commenter noted, even when the EPA 
sets a work practice standard, such a standard must still be consistent 
with CAA sections 112(d)(2) and (3). The commenter rejected the EPA's 
rationale for the CAA section 112(h) determination in the proposal that 
``application of a measurement methodology for PRDs that vent to 
atmosphere is not practicable due to technological and economic 
limitations.'' The commenter stated that the EPA's statement is false, 
and that the EPA's proposed reporting and recordkeeping requirements 
would mandate facilities ``calculate the quantity of organic HAP 
released during each pressure release event.'' According to the 
commenter, a 2007 SCAQMD report found that ``new (wireless) technology 
allows for continuous monitoring of PRDs without significant capital 
expense and makes it easy for operators to identify valve leaks . . . 
VOCs that are emitted from PRDs may be accurately identified, 
estimated, remedied, and reported immediately.'' \10\ The commenter 
stated this monitoring technology is already in use at refineries in 
the United States,\11\ and noted that SCAQMD required refineries to 
install wireless monitoring on 20 percent of the PRDs at their 
facilities since 2003 and on all PRDs since 2009.\12\ The commenter 
noted that the EPA also relied on TCEQ data from seven ethylene 
production facilities that reported the quantity of HAP emissions 
released during specific PRD release events. For these reasons, the 
commenter argued that it is possible to measure PRD emissions, and they 
actually have been measured. The commenter stated that the EPA has not 
shown and cannot show why, in view of existing data on the amount, 
duration, and types of PRD releases, it cannot set a limit on these 
releases. The commenter further asserted that PRD releases may be 
captured and controlled; therefore, the EPA cannot use a work practice 
standard under CAA sections 112(h)(1) and (2)(A) to justify failing to 
set an appropriate numerical emission standard for them.
---------------------------------------------------------------------------

    \10\ The commenter provided the following reference: SCAQMD, 
Rule 1173, Control of Volatile Organic Compound Leaks and Releases 
from Components at Petroleum Facilities and Chemical Plants (amended 
February 6 2009), https://www.arb.ca.gov/DRDB/SC/CURHTML/R1173.PDF, 
EPA-HQ-OAR-2010-0682-0761; SCAQMD, Final Staff Report for Proposed 
Amended Rule 1173--Control of Volatile Organic Compound Leaks and 
Releases from Components at Petroleum Facilities and Chemical Plants 
at 3-2 (May 15, 2007), Docket ID Item No. EPA-HQ-OAR-2010-0869-0024.
    \11\ The commenter provided the following reference: Rosemount 
Wireless Instrumentation, Refinery Improves Environmental Compliance 
and Reduces Costs with Wireless Instruments (2007) (``the result has 
been . . . true time and rate calculations for brief emissions''), 
https://www2.emersonprocess.com/siteadmincenter/PM%20Rosemount%20Documents/00830-0100-4420.pdf; see also Adaptive 
Wireless Solutions, Continuous Valve Monitoring for Product Loss 
Prevention, Emission Reduction and ROI at 2, https://www.chemicalprocessing.com/assets/Media/MediaManager/Continuous_Monitoring_for_ROI.pdf; Meeting Record for August 4, 
2015, Representatives of Emerson Process Management and 
Representatives of Office of Air Quality Planning and Standards 
(U.S. EPA), Docket ID Item No. EPA-HQ-OAR-2010-0682-0743 (meeting 
regarding PRD monitoring tools and technologies).
    \12\ The commenter provided the following reference: SCAQMD, 
Staff Report at ES-2, 2-3 to 2-5, Docket ID Item No. EPA-HQ-OAR-
2010-0869-0024.
---------------------------------------------------------------------------

    A commenter further objected to the proposed work practice 
standards because, they asserted, the EPA proposed the standards in 
part on the basis that the cost of measuring emissions is too high. The 
commenter stated that the EPA must set a MACT floor without 
consideration of cost, and that the cost is reasonable if 12 percent of 
existing sources met the limitation. The commenter argued that although 
the EPA stated that it would be economically prohibitive to construct 
an appropriate conveyance and install and operate continuous monitoring 
systems for each individual PRD that vents to atmosphere, the EPA fails 
to provide the estimated cost for construction and installation of such 
monitoring systems. The commenter argued that any such calculation 
would need to consider the impact of the EPA and state imposed flaring 
reduction programs, and the social and economic cost of the excess 
emissions from PRD emissions, including costs associated with the 
disruption in communities that are subject to ``shelter in place'' 
programs because of episodic releases from facilities.
    Response: We disagree with the commenter's assessment and maintain 
the rationale provided in the proposal preamble (84 FR 54302, October 
9, 2019), where we specifically discussed the issue related to 
constructing a conveyance and quantitatively measuring PRD releases and 
concluded that these measures were not practicable and that a work 
practice standard was appropriate. Owners or operators can estimate the 
quantity of HAP emissions released during a PRD release event based on 
vessel operating conditions (temperature and pressure) and vessel 
contents when a release occurs, but these estimates do not constitute a 
measurement of emissions or emission rate within the meaning of CAA 
section 112(h). The monitoring technology suggested by the commenter is 
adequate for identifying PRD releases and is one of the acceptable 
methods that facility owners or operators may use to comply with the 
continuous monitoring requirement. However, we disagree that it is 
adequate for accurately measuring emissions for purposes of determining 
compliance with a numeric emission standard. The technology cited by 
the commenter is a wireless monitor that provides an indication that a 
PRD release has occurred, but it does not provide information on either 
release quantity or composition. PRD release events are characterized 
by short, high pressure, non-steady state conditions that make such 
releases difficult to quantitatively measure. As such, we maintain our 
position that the application of a work practice standard is 
appropriate for PRDs.
    Comment: We received comments in support of and against the 
proposed work practice standards for PRDs. Specific comments against 
the proposal related to whether they apply at all times.
    A commenter stated that even assuming arguendo that the EPA could 
set a work practice standard for PRDs and that it otherwise had 
satisfied CAA sections 112(h) and (d), its action is unlawful because 
there would be no restriction that applies continuously as

[[Page 40406]]

the CAA directs.\13\ The commenters stated that the proposed rule would 
permit an uncontrolled amount of HAP to be released by a PRD 
repeatedly, when it is opened at the facility's sole discretion. A 
commenter stated this means that once or twice every 3 years and 
whenever there is a force majeure event, any amount of HAP that may 
come from these devices could be released, and would not be a 
violation, no matter the original source of emissions.
---------------------------------------------------------------------------

    \13\ The commenter provided the following reference: Sierra 
Club, 551 F.3d at 1028; CAA section 304(k).
---------------------------------------------------------------------------

    A commenter argued that the fact that the EPA required three non-
defined steps (including monitoring mechanisms, such as flow 
indicators, routine inspection and maintenance, and operator training) 
to be taken to try to prevent such releases does not mean that there is 
a continuous CAA section 112-compliant emission standard that applies. 
The commenter stated that none of these steps would restrict pollution 
released during PRD openings, would make the PRD malfunction exemptions 
lawful, or would turn them into a standard instead of an exemption. The 
commenter noted that although there are some potential controls listed 
as work practice requirements that a facility may choose to implement 
(e.g., ``deluge systems'' and ``staged relief systems where the initial 
PRD discharges to a control system''), the proposed rule does not 
require any facility to either install them or any other controls or 
limits on PRDs. The commenter stated this should be required pursuant 
to the MACT floor, as the best performing PRDs are controlled, and the 
best performing process units are not equipped with any PRDs that are 
capable of venting emissions directly to the atmosphere.
    The commenter stated that because analyses, reports, and potential 
corrective action steps would be required after such releases occur, 
that does not mean that the EPA has implemented a continuous emission 
standard. The commenter also stated that uncontrolled releases are not 
considered a violation, and there is no civil penalty for the HAP 
emitted during the allowable PRD releases. Under the proposed rule, the 
commenter argued, no matter how many corrective actions a facility may 
take afterward, the release would still be an authorized release, 
allowing an unlimited amount of toxic air pollution to be emitted into 
the air from facility equipment albeit through a PRD. The commenter 
said that post-hoc measures may help discover why a release happened, 
and might even help to prevent release, but these measures are not 
considered controls or limits on the pollution that was released. The 
commenter stated that the EPA additionally failed to propose any 
regulatory requirement to end PRD releases as soon as it is discovered.
    Another commenter agreed that the EPA has the authority and 
obligation to adopt work practice standards under the Sierra Club SSM 
decision. The commenter reiterated the Sierra Club decision and said 
the EPA must ensure that some ``emission standard'' applies at all 
times--except that the standard that applies during normal operation 
need not be the same standard for SSM periods. The commenter said the 
requirement for ``continuous'' standards means only that a facility may 
not install control equipment and then turn it off when atmospheric 
conditions are good; and it does not mean that work practice standards 
must physically restrict emissions from all equipment at all times. The 
commenter said that the EPA has consistently imposed as ``MACT'' 
standards a variety of work practice obligations that do not prohibit 
or limit emissions to a specified level at all times, but rather are 
designed to limit overall emissions from various processes over the 
course of a year. The commenter said the EPA's own LDAR programs 
illustrate this distinction. The commenter contended that no court has 
suggested that periods of ``unlimited emissions'' [e.g., 40 CFR 
63.119(b)(1) (internal floating roof allowed not to contact with stored 
material during filling/emptying); 40 CFR 63.119(b)(6) (covers on tank 
openings may be opened when needed for access to contents); 40 CFR 
63.135(c)(2) (allowing openings on containers as necessary to prevent 
physical damage)] render these requirements insufficient under CAA 
section 112. Rather, the work practice standards associated with these 
requirements--e.g., maintaining openings in a closed position except as 
necessary for access; conducting filling/emptying as rapidly as 
possible--are considered to be acceptable mechanisms to minimize 
overall emissions from these types of equipment, even when they do not 
limit emissions at all during a few brief periods that are necessary 
for operational or safety reasons.
    Response: We disagree with the underlying premise of the first 
commenter that any PRD release should be deemed a violation of section 
112 and must be directly enforceable. As we have explained, we believe 
that a work practice standard, rather than a numerical limit applicable 
to each PRD release is appropriate. To the extent the commenter is 
claiming that a standard does not apply at all times, we also disagree. 
Although there is not a numerical limit that each PRD must meet at all 
times, we have established a work practice standard that does apply at 
all times. The work practice standard for PRDs requires operators to 
adopt prevention measures to minimize the likelihood of PRD release 
events, and the installation and operation of continuous monitoring 
device(s) to identify when a PRD release has occurred. These measures 
must be complied with at all times, and thus the work practice standard 
does apply at all times. (See for example, Mexichem Specialty Resins, 
Inc. v. EPA, 787 F.3d 544, 560 (D.C. Cir. 2015) (``The regulations 
anticipate that regulated entities will be allowed to open bypasses 
during maintenance as long as they comply with the opening provisions 
set forth therein.''). Additionally, having a backstop on the number of 
PRD releases allowed and requiring root cause analysis and corrective 
action analysis will ensure PRD releases are further minimized. We also 
note that we have always (since the rule was initially promulgated) had 
requirements in our equipment leaks regulations at 40 CFR 63.1030(c) 
for the Ethylene Source category that ensure a PRD has properly 
reseated after a release. We agree with the second commenter that there 
are a variety of work practice standards the EPA has adopted in its 
section 112 regulations that operate similar to the PRD requirements in 
that they do not prohibit emissions from equipment at all times or 
otherwise establish numeric limits for emissions from those pieces of 
equipment.
    Comment: Commenters stated that the EPA cannot use CAA section 
112(h) to allow unlimited HAP releases from PRDs because the 
authorizations for uncontrolled PRD releases are back-door exemptions 
from the other underlying standards regulating ethylene production 
facilities. For uncontrolled PRD releases, the commenter asserted that 
the EPA did not and could not reasonably explain how it is lawful to 
authorize completely uncontrolled emissions under CAA section 112(h). 
The commenter noted that the Court previously upheld a decision not to 
create a malfunction or ``excursion'' provision.\14\
---------------------------------------------------------------------------

    \14\ The commenter provided the following reference: 
Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 1057 (D.C. Cir. 1978) 
(citing Am. Petrol. Inst. v. EPA, 540 F.2d 1023, 1036 (10th Cir. 
1976) (denying excursions)).
---------------------------------------------------------------------------

    The commenter argued that historically there has been no limit on

[[Page 40407]]

emissions when a PRD acts like a process vent, and that the EPA's 
purpose in conducting this rulemaking was, in part, to remove these 
unlawful exemptions as compelled by law. The commenter warns that the 
EPA's proposed rule reinstates new versions of precisely the same sort 
of exemptions, by allowing at least one, and in some instances two 
``free passes'' to emit uncontrolled pollution every 3-year period for 
each PRD. The commenter further remarked that exempting such emissions 
from the definition of violation negates the meaning of ``emission 
standard,'' and shows that no standard applies to these releases.
    The commenter stated that the EPA cannot create any exemption from 
or weakening of EMACT equipment standards simply because excess 
emissions from equipment are routed through a PRD. The commenter argued 
that doing so unlawfully weakens the original CAA section 112(d) 
standards for the linked equipment, without any reasoned explanation or 
support for doing so. Further, the commenter stated that because the 
EPA proposes that no emission standard applies during the uncontrolled 
releases, the exemptions violate CAA sections 112(d) and 302(k) and 
flout the Court's decisions in these cases, and also conflict with the 
EPA's decision not to create an unlawful exemption in the Boilers 
case.\15\ The commenter stated that the EPA provided no statutory 
explanation or interpretation of how its action could comport with CAA 
sections 112 and 302(k), therefore, if the EPA were to finalize these 
exemptions, the EPA would open itself up to a violation of the CAA's 
core rulemaking requirements applicable to CAA sections 112(d) and (f) 
standards.
---------------------------------------------------------------------------

    \15\ The commenter provided the following reference: See U.S. 
Sugar Co., 830 F.3d at 607-08.
---------------------------------------------------------------------------

    The commenter asserted that the proposed rule therefore seeks to 
establish major exemptions that allow uncontrolled releases due to 
predictable and often-repeated malfunctions. The commenter noted that 
the even though the standard explicitly defines a violation as the 
second or even the third such release from the same PRD during a 3-year 
period, whether the second uncontrolled release from the same PRD is a 
violation depends on if the release has the same root cause. The 
commenter stated that PRDs are not independent emission points, and 
that PRDs never release pollution into the air or smoke unless there is 
a malfunction. The commenter also asserted that the EPA's attempt to 
define a new way in which a facility can claim excess emissions are not 
a violation echoes the ``affirmative defense'' provision the Court held 
unlawful in NRDC, 749 F.3d 1055, 1064 (D.C. Cir. 2013). The commenter 
argued that the EPA may not flout statutory constraints Congress 
enacted in its discretion by trying to remove civil penalty liability 
for excess emissions that violate the CAA and increase human exposure 
to toxic air pollution directly, contrary to the CAA. The commenter 
pointed to the cement kilns case, in which they asserted the EPA tried 
to claim that the unlawful affirmative defense to civil penalties was 
``part of the emission standard,'' noted that the Court rejected these 
arguments in NRDC, 749 F.3d 1055, 1064 (D.C. Cir. 2013), and argued 
that precedent would apply equally here.\16\ The commenter further 
argued that the proposed rule, by allowing owners or operators to 
conduct root cause analyses for these events, essentially permits 
owners or operators--not the courts--to make the determination whether 
they should be subject to enforcement or penalties for certain PRD 
releases, which determines whether an event is either actionable (i.e., 
the result of operator error or poor maintenance, or whether it was the 
result of the same root cause as a prior event). The commenter further 
stated that the proposed exemptions contravene the citizen suit and 
penalty provisions by creating a de facto complete defense (not just an 
affirmative defense) from civil penalties for certain uncontrolled 
emission releases that would otherwise constitute violations. The 
commenter pointed to a ruling by the Court that explained how creating 
such a multi-stage complicated assessment to determine if a violation 
has occurred undermines the purpose of the CAA and the ability to 
enforce it.\17\
---------------------------------------------------------------------------

    \16\ The commenter provided the following reference: EPA, 
NESHAP, Portland Cement Summary of Public Comments and Responses at 
124-25 (December 20, 2012) (``EPA's view is that the affirmative 
defense is part of the emission standard and defines two categories 
of violation.'').
    \17\ The commenter provided the following reference: ``Once 
excursion provisions are promulgated, an enforcement case no longer 
turns on the sharply defined issue of whether the plant discharged 
more pollutant than it was allowed to, but instead depends on murky 
determinations concerning the sequence of events in the plant, 
whether those events would have been avoidable if other equipment 
had been installed, and whether the discharge was within the intent 
of the excursion provision. Consequently, what Congress planned as a 
simple proceeding suitable for summary judgments would become a form 
of inquest into the nature of system malfunction.'' Weyerhaeuser, 
590 F.2d at 1058.
---------------------------------------------------------------------------

    According to the commenter, by granting this exemption, the EPA may 
incentivize facilities to release large amounts of HAP through PRDs 
rather than flares to avoid using one of their ``free passes'' for the 
prohibition on visible smoke emissions from flares. Instead of meeting 
the CAA section 112 standards that apply to other facility equipment 
routed to PRDs or flares, the commenter asserted that exemptions 
authorize a facility to violate those limits and have no liability if 
the excess emissions are emitted directly into the air. The commenter 
stated that this even creates a perverse incentive for operators to 
install redundant PRDs on process equipment. The commenter also stated 
that, at the very least, the EPA must include regulations prohibiting 
the installation of new redundant PRDs to circumvent the prohibition on 
atmospheric releases.
    The commenter further stated that emissions from malfunctions at 
ethylene production facilities that are released through PRDs are a 
significant source of underestimated HAP emissions. The commenter 
suggested that the emissions from PRD releases are a substantial 
problem for the industry as a whole when viewed over time. Further, the 
commenter argued that there is no upper limit on the amount of 
pollution an individual PRD event can release to the atmosphere. The 
commenter asserted that the EPA's proposed exemptions would, therefore, 
bar enforcement action against the worst events.
    A commenter observed that uncontrolled PRD releases are preventable 
and avoidable, and that they need not occur if a facility avoids over-
pressure in the system. The commenter referred to the proposal 
preamble, noting that such ``pressure build-ups are typically a sign of 
a malfunction of the underlying equipment,'' and PRDs ``are equipment 
installed specifically to release during malfunctions.'' Therefore, the 
commenter argued that the EPA cannot rely on any argument that 
equipment can fail, and that PRDs are necessary to address over-
pressure and avoid a larger safety incident, and that the EPA has not 
relied on or demonstrated with any evidence that it is a valid concern. 
The commenter stated that even if it may be considered by the EPA in an 
administrative enforcement context or by the courts in an enforcement 
case, the EPA cannot authorize, up front, a whole set of problematic 
releases.
    The commenter stated that the proposed malfunction standards for 
PRDs also break with prior Agency policy regarding malfunctions and for 
the use of case-by-case enforcement discretion to address malfunctions. 
The commenter stated that the Agency has repeatedly explained why case-
by-case

[[Page 40408]]

evaluation of such issues is the only workable approach, and has 
repeatedly finalized prohibitions on uncontrolled releases from PRDs 
that vent directly to the atmosphere, fully aware that allowing such 
releases without an emission limit is a malfunction exemption 
prohibited both by the CAA and the Court's decision in Sierra Club. The 
commenter objected to this change and indicated that the EPA has failed 
to clearly explain this break with prior precedent.\18\ The commenter 
noted that the EPA finalized similar provisions prohibiting PRD 
releases in MACT standards for Group IV Polymers and Resins, Pesticide 
Active Ingredient Manufacturing, and Polyether Polyols Production. The 
commenter further stated that the Court recently upheld this type of 
prohibition in Mexichem Specialty Resins, Inc. v EPA, 787 F.3d 544, 
560-61 (DC Cir. 2015) and urged the EPA to finalize the standards for 
PRD as proposed. The commenter noted that in light of the EPA's prior 
policy, there can be ``no doubt'' that prohibiting uncontrolled PRD 
releases is lawful and consistent with the CAA. The commenter stated 
that the EPA has neither provided a reasoned explanation for the 
exemptions, nor acknowledged or explained the break in its prior policy 
against malfunction exemptions.
---------------------------------------------------------------------------

    \18\ The commenter provided the following references: See, FCC 
v. Fox, 556 U.S. 502, 516 (2009) (citing Motor Vehicle Mfrs. Ass'n 
v. State Farm Mutual Automobile Insurance Co., 463 U.S. 29, 42 
(1983)) (``the requirement that an agency provide reasoned 
explanation for its action would ordinarily demand that it display 
awareness that it is changing position. An agency may not, for 
example, depart from a prior policy sub silentio or simply disregard 
rules that are still on the books.''); see also Encino v. Navarro, 
136 S.Ct. 2117, 2125-26 (2016) (reaffirming FCC v. Fox and noting 
the need to explain changes in agency policy based on actual facts 
and circumstances).
---------------------------------------------------------------------------

    Response: We disagree that PRDs are simply bypasses for emissions 
that are subject to emission limits and controls and that they, thus, 
allow for uncontrolled emissions without violation or penalty. PRDs are 
generally safety devices that are used to prevent equipment failures 
that could pose a danger to the facility and facility workers. PRD 
releases are triggered by equipment or process malfunction. As such, 
they do not occur frequently or routinely and do not have the same 
emissions or release characteristics that routine emission sources 
have, even if the PRD and the vent are on the same equipment. This is 
because conditions during a PRD release (temperature, pressure, and 
vessel contents) differ from the conditions that exist during routine 
emissions from equipment. For example, emissions from ethylene process 
vents are predictable and must be characterized for emission potential 
and applicable control requirements prior to operation in the 
facility's NOCS report. In addition, PRDs must operate in a closed 
position and must be continuously monitored to identify when releases 
have occurred.
    Under the final rule, if an affected PRD releases to the 
atmosphere, the owner or operator is required to perform root cause 
analysis and corrective action analysis as well as implement corrective 
actions and comply with the specified reporting requirements. The work 
practice standard also includes criteria for releases from affected 
PRDs that would result in a violation at 40 CFR 63.1107(h)(3)(v). We 
also note that a facility cannot simply choose to release pollutants 
from a PRD; any release that is caused willfully or caused by 
negligence or operator error is considered a violation.
    We also disagree that PRDs are not independent emission points and 
instead function in venting emissions from other emission points during 
a malfunction. The commenter incorrectly suggests that the PRD work 
practice standard replaces the existing emission standards for 
connected equipment. The amendments to the NESHAP addressing PRDs do 
not affect requirements in the NESHAP that apply to equipment 
associated with the PRD. For example, compliance with the PRD 
provisions are required in addition to requirements for ethylene 
process vents for the same equipment. We also disagree with the comment 
that the standards for PRDs also break with prior agency policy 
regarding malfunctions. As commenters correctly note, the EPA has 
indeed both set work practice standards for PRDs and prohibited PRD 
releases in other source categories. As explained at proposal, however, 
the basis of the work practice standards promulgated for PRD releases 
in the Petroleum Refinery Sector RTR (80 FR 75178, December 1, 2015) 
were our underlying basis for the proposed work practice standards for 
PRD releases for facilities in the Ethylene Production source category 
(84 FR 54303, October 9, 2019).
    The EPA evaluated the best performing facilities in determining the 
appropriate work practice standard, and as a result considered 
requirements established in the SCAQMD and BAAQMD rules and the 
Chemical Accident Prevent Provisions rule (84 FR 54303, October 9, 
2019). These rules are the only rules we are aware of that address the 
infrequent and unpredictable nature of PRD releases. The EPA 
established a MACT standard based on these rules, and as part of this, 
we determined that either two or three PRD releases (depending on the 
root cause) from a single PRD in a 3-year period is a violation of the 
work practice standard.
    Regarding citizen suits, we note that the regulations do not 
specify that the EPA Administrator would make a binding determination 
regarding whether a PRD release is in compliance or a violation, and 
the issue could be argued and resolved by a court in the context of a 
citizen suit.
    Comment: We received comments in support of and against the work 
practice standards calling for root cause analysis and certain 
corrective actions. Some commenters supported the EPA's assessment that 
even at the best performing sources, releases from PRDs are likely to 
occur and cannot be safely routed to a control device. A commenter said 
the EPA's conclusion is consistent with company's experiences that 
pressure release actuation events, while infrequent, will occur even at 
properly designed and operated sources, including the best performers. 
Another commenter said that although they agree with the EPA's 
conclusion that it is not cost effective to control all PRD releases to 
the atmosphere, they do not agree that a root cause analysis and 
corrective action is a warranted work practice in every situation where 
a PRD relieves to the atmosphere and should not be required as part of 
the work practice standard for every PRD release. The commenter stated 
that under the Chemical Accident Prevention Program at 40 CFR 68.81(a), 
an incident investigation with root cause analysis is required only 
when the release is a catastrophic release or ``could reasonably have 
resulted in a catastrophic release.'' The commenter said that a 
``catastrophic release'' is defined as a ``major uncontrolled emission, 
fire, or explosion, involving one or more regulated substances that 
presents imminent and substantial endangerment to public health and the 
environment.'' The commenter argued that the EPA has not established 
sufficient evidence in the background documents for this rulemaking to 
indicate that conducting a root cause analysis routinely for all PRD 
releases regardless of whether they meet the definition of 
``catastrophic release'' is being performed by the best performing 
sources in the Ethylene Production source category.
    Another commenter asserted that the EPA did not set a standard for 
PRDs that complies with the CAA requirements to assure both the 
``average emission limitation achieved'' by the relevant best-
performing sources and the

[[Page 40409]]

``maximum degree of emission reduction'' that is ``achievable'' and, 
therefore, the EPA's proposed standards for PRDs do not meet the CAA 
sections 112(d)(2) and (3) test. The commenter states there is no 
discussion in the proposed rule of these factors for PRD releases, much 
less an analysis or determination that allowing one--two uncontrolled 
releases every 3 years (plus force majeure event releases) reflects, at 
minimum, the average of the best performers' reductions, and is the 
``maximum achievable degree of emission reduction.''
    The commenter stated that the TCEQ data that the EPA relies on 
clearly demonstrate that at least 23 percent (likely higher) of 
ethylene production facilities have zero atmospheric releases. The EPA 
reviewed roughly 30 percent of all operating ethylene production 
facilities (i.e., seven of 26 ethylene production facilities) in the 
source category that were chosen at random. The commenter notes that 
only one of the events was actually an atmospheric PRD release on a 
properly operating PRD, which means that six facilities, or 23 percent 
of all operating ethylene production facilities, had no atmospheric 
releases on a properly operating PRD. The commenter noted that the 
number of ethylene production facilities with zero atmospheric releases 
is higher. The commenter also stated that the EPA has not explained why 
it relied on data from the petroleum refinery sector when data for 
ethylene production facilities is readily available and relied on 
elsewhere in the rulemaking. The commenter noted that compliance data 
for refineries from 2019 under the 2015 Petroleum Refineries NESHAP 
that is publicly available shows that the average uncontrolled PRD has 
far fewer releases to the atmosphere than the EPA claims that the best 
performers do, and that the best-performing uncontrolled PRDs are 
likely to have no atmospheric releases over a 3-year period. The 
commenter provided data from 40 CFR part 63, subpart CC compliance 
reports available on the websites of state environmental agencies in 
Louisiana, Texas, and Indiana for 10 refineries that collectively 
represented approximately 1,030 uncontrolled PRDs. The commenter noted 
that these data suggest that the EPA is proposing a number of releases 
that is exponentially higher than what has been demonstrated by real-
world results from refineries thus far, and that the average 
uncontrolled PRD from the average refinery has far fewer than the two 
or three releases to the atmosphere over 5 years that the EPA claims 
that the best performers do.
    A commenter argued that the EPA should set a zero emission limit 
for all PRDs because the best-performing PRD has no emissions to the 
atmosphere and the average of the best-performing 12 percent emit 
nothing to the atmosphere. The commenter stated that since the emission 
limitation for new sources is to reflect the performance of best 
performing PRD, new PRDs would presumably be required to capture and 
return discharges to process units; existing PRDs would have to meet 
the average of the best performing PRD, which could not be less 
stringent than the emission rate of the best performing PRD controlled 
by flares.
    A commenter recommended that the EPA require new and modified 
atmospheric PRDs or existing PRDs on modified process equipment to be 
routed to the fuel gas system, flare, or other control device that 
achieves 98-percent destruction efficiency, pursuant to the MACT floor, 
as the best performing PRDs are controlled and the best performing 
process units are not equipped with any PRDs that are capable of 
venting emissions directly to the atmosphere. The commenter requested 
that the EPA propose that uncontrolled HAP emissions no longer be 
allowed from a PRD, and any releases from such devices would have to be 
routed through a control device.
    The commenter further stated that the EPA's determination on PRDs 
was based on review of SCAQMD and BAAQMD adopted programs that attempt 
to reduce uncontrolled releases from PRDs, with generally more 
stringent emission limitations and LDAR programs than federal programs. 
The commenter stated that the EPA should adopt the best features of 
those programs in strengthening the NESHAP, but that these efforts were 
not subject to or aiming to satisfy the MACT floor requirements of the 
CAA, nor are they determinative of the MACT floor for PRDs, which must 
be based on the level of control ``achieved in practice'' by the 
relevant best-performing 12 percent of emission sources (for existing 
sources), or the best single source (for new sources).
    According to the commenter the SCAQMD data on PRD releases from 
refineries shows that five out of eight (more than 50 percent) of 
regulated facilities reported zero atmospheric PRDs releases between 
2010 and 2015 (the total number of refineries in the SCAQMD data do not 
include those operated by Alon Refining, which were idled in 2012). 
Thus, the commenter stated that the SCAQMD data demonstrate that the 
best performing PRDs do not release emissions directly to the 
atmosphere.
    The commenter further stated that the EPA has not actually 
implemented the requirements of the BAAQMD and SCAQMD programs, and 
that the BAAQMD and SCAQMD programs are far more protective than the 
proposed rule. First, the commenter noted the BAAQMD requires that the 
operator must control (via flare or routing to a process unit) all PRDs 
that discharge for a second time in a 5-year period, whereas the SCAQMD 
rules include a similar provision, but offer as an alternative payment 
of a fee of $350,000 for each PRD that is not controlled. The commenter 
added that SCAQMD rules also require control of any PRD that has a 
single large release of greater than 2,000 pounds per day (lbs/day). 
Second, the commenter noted the BAAQMD and SCAQMD rules require the use 
of three redundant systems, including worker training, inspection, and 
maintenance, and two redundant ``hardware'' oriented systems. The third 
significant difference noted by the commenter is the greater number of 
releases allowed by the option to parse releases by ``root cause.''
    The commenter also stated that the EPA appears to have 
inappropriately categorized PRDs in its analysis. The commenter noted 
that the EPA stated it intended to regulate ``atmospheric'' PRD 
releases, i.e., releases to the atmosphere, including those vented to a 
control device, however, in the proposed rule, the EPA appears to have 
effectively ignored the ``best controlled'' PRDs (those routed to 
processes with no discharge to the environment) and the ``well-
controlled'' PRDs (those routed to high quality flares) and determined 
the MACT floor based on PRDs with some lesser level of regulation. The 
commenter stressed that the CAA does not allow the EPA to categorize in 
this manner (see CAA section 112(d)(1) (allowing the EPA only to 
``distinguish among classes, types, and sizes of sources'')).
    Response: At proposal, the EPA provided extensive discussions on 
why it was appropriate to establish a work practice standard for PRDs 
that vent to atmosphere, under CAA section 112(h). 84 FR 54302-304. We 
explained that no ethylene production facility is subject to numeric 
emission limits for PRDs that vent to the atmosphere. We posited that 
the EPA did not believe it was appropriate to subject PRDs that vent to 
the atmosphere to numeric emission limits due to technological and 
economical limitations that make it impracticable to measure emissions 
from such PRDs. We further explained

[[Page 40410]]

that CAA section 112(h)(1) allows the EPA to prescribe a work practice 
standard or other requirement, consistent with the provisions of CAA 
section 112(d) or (f), in those cases where, in the judgment of the 
Administrator, it is not feasible to enforce an emission standard. 
Additionally, we explained that CAA section 112(h)(2)(B) defines the 
term ``not feasible'' in this context as meaning that ``the application 
of measurement technology to a particular class of sources is not 
practicable due to technological and economic limitations.'' We also 
noted that the basis of the work practice standards promulgated for PRD 
releases in the Petroleum Refinery Sector RTR (80 FR 75178, December 1, 
2015) were our underlying basis for the proposed work practice 
standards at ethylene production facilities. 84 FR 54303.
    As a general matter, CAA section 112 requires MACT for existing 
sources to be no less stringent than ``the average emission limitation 
achieved by the best performing 12 percent of the existing sources (for 
which the Administrator has emissions information). . .'' [(CAA section 
112(d)(3)(A)]. ``Emission limitation'' is defined in the CAA as ``. . 
.a requirement established by the State or Administrator which limits 
the quantity, rate, or concentration of emissions of air pollutants on 
a continuous basis, including any requirement relating to operation or 
maintenance of a source to assure continuous emission reduction, and 
any design, equipment, work practice, or operational standard 
promulgated under this chapter'' [CAA section 302(k)]. The EPA 
specifically considers existing rules from state and local authorities 
in identifying the ``emission limitations'' for a given source. We then 
identify the best performers to identify the MACT floor (the no less 
stringent than level) for that source. The EPA identified the 
requirements established in the SCAQMD and BAAQMD rules, and the 
Chemical Accident Prevent Provisions rule (40 CFR part 68) as the basis 
of the MACT floor because they represented the requirements applicable 
to the best performing sources. 84 FR 54303. Work practice standards 
are established in place of a numeric limit where it is not feasible to 
establish such limits. Thus, in a case such as this, where the EPA has 
determined that it is appropriate to establish work practice standards, 
it was reasonable for the EPA to identify the rules that impose the 
most stringent requirements and, thus, represent what applies to the 
best performers, and then to apply the requirements from those rules as 
MACT.
    We recognize that the proposed standard for PRDs did not exactly 
mirror the SCAQMD, BAAQMD, or Chemical Accident Prevent Provisions 
rules exactly, but consider the requirements to be comparable. For 
example, we did not include a provision similar to that in the SCAQMD 
rule that excludes releases less than 500 lbs/day from the requirement 
to perform a root cause analysis; that provision in the SCAQMD rule 
does not include any other obligation to reduce the number of these 
events. Similarly, we did not include a provision that only 
catastrophic PRD releases must be investigated, as the commenter noted. 
Rather than allowing unlimited releases less than 500 lbs/day or that 
are not considered catastrophic, we require a root cause analysis for 
releases of any size. Because we count small releases that the SCAQMD 
rule does not regulate at all, we considered it reasonable to provide a 
higher number of releases prior to considering the owner or operator to 
be in violation of the work practice standard. We also adopted the 
three prevention measures requirements in the BAAQMD rule with limited 
modifications. After considering the PRD release event limits in both 
the SCAQMD and BAAQMD rules, we determined it was reasonable and 
appropriate to establish PRD requirements consistent with the flare 
work practice standard provisions in the SCAQMD and BAAQMD rules. 
Therefore, the final requirements provide that two or three events 
(depending on the root cause) from the same PRD in a 3-calendar-year 
period is a violation of the work practice standard. We also note that 
a facility cannot simply choose to release pollutants from a PRD; any 
release that is caused willfully or caused by negligence or operator 
error is considered a violation.
    With respect to subcategorizing PRDs into those that vent to the 
atmosphere versus those that vent to a control system, we note that the 
only information we have available about when PRD releases occur at 
ethylene production facilities are from those PRDs that release 
directly to atmosphere. Regardless of whether we subcategorize or not, 
the best performing PRD for which we have information had one release 
over a 7-year period, and the backstop for how many releases are 
allowed to occur is based on this information over a long-term period 
of time given the random nature of when a PRD release might occur.
    In summary, the work practice standard we are finalizing provides a 
comprehensive program to manage entire populations of PRDs and includes 
prevention measures, continuous monitoring, root cause analysis, and 
corrective actions, and addresses the potential for violations for 
multiple releases over a 3-year period. We followed the requirements of 
section 112 of the CAA, including CAA section 112(h), in establishing 
what work practice constituted the MACT floor.
    Comment: Commenters requested that the EPA add a standard for 
minimizing emissions arising from degassing storage vessels that are 
complying with the control requirements in Table 7 to 40 CFR 
63.1103(e). A commenter explained this request is due to their current 
interpretation of the proposed rule, wherein 40 CFR 63.1108(a)(5) no 
longer applies, and, thus, facilities may be required to vent to 
control devices at all times, even during degassing events. A commenter 
stated that the current rule requires facilities to address 
minimization of emissions from shutdown, which includes degassing, in 
the SSM plan required by 40 CFR 63.1111; and facilities have 
historically considered degassing emissions from shutdown of storage 
vessels to be covered by their SSM plans per 40 CFR 63.1108(a)(5) and 
relied on the language in 40 CFR 63.1108(a)(5) that back-up control 
devices are not required. The commenter requested the EPA subcategorize 
storage vessel degassing emissions as maintenance vents based on class, 
just as the EPA proposed for process vents. The commenter remarked that 
the Texas permit conditions presented in the memorandum, Review of 
Regulatory Alternatives for Certain Vent Streams in the Ethylene 
Production Source Category, apply equally to both maintenance vents and 
degassing of storage vessels and stated these permit conditions reflect 
what the best performers have implemented for storage vessel degassing 
(for both fixed and floating roofs) for both new and existing sources. 
According to the commenter, it is not feasible to control all the 
emissions from the entire storage vessel emptying and degassing event 
and at some point, the storage vessel must be opened and any remaining 
vapors vented to the atmosphere. The commenter further stated that this 
venting of vapors to the atmosphere is similar to the EPA description 
for maintenance vents in the preamble to the proposed rule.
    The commenter stated that the EPA referenced the memorandum, 
Impacts for Control Options for Storage Vessels at Petroleum Refineries 
(Docket Item ID

[[Page 40411]]

No. EPA-HQ-OAR-2010-0682-0199), as part of the EMACT storage vessel 
technology review, in which the EPA concluded that degassing controls 
for storage vessels were not cost effective. Additionally, the 
commenter said that in the EPA's summary of public comments and 
responses to the 2014 proposal for the Petroleum Refinery NESHAP RTR, 
the EPA stated: ``. . . if a control device is used to comply with this 
final rule during normal operations, then such a control device must be 
used at all times, including during degassing of the storage vessel. 
Any bypassing of emissions from being routed to a control device to 
being routed to the atmosphere would be considered a violation of the 
standard.''
    Response: We agree with the commenters that complying with the 
storage vessel requirements in Table 7 at 40 CFR 63.1103(e)(3)(b) and 
(c) is not appropriate during storage vessel degassing events and a 
separate standard for storage vessel degassing is necessary, due to the 
nature of the activity. With the removal of SSM requirements, as 
proposed, a standard specific to storage vessel degassing does not 
exist when storage vessels are using control devices to comply with the 
requirements in Table 7 to 40 CFR 63.1103(e). We also agree with the 
commenters that storage vessel degassing is similar to maintenance 
vents (e.g., equipment openings) and that there must be a point in time 
when the storage vessel can be opened and any emissions vented to the 
atmosphere. In response to this comment, therefore, we reviewed 
available data to determine how the best performers are controlling 
storage vessel degassing emissions.
    We are aware of the following three regulations that address 
storage vessel degassing, two in the state of Texas and the third for 
the SCAQMD in California. Texas has degassing provisions in the Texas 
Administrative Code (TAC) (30 TAC Chapter 115, Subchapter F, Division 
3. See https://texreg.sos.state.tx.us/public/readtac%24ext.ViewTAC?tac_view=5&ti=30&pt=1&ch=115&sch=F&div=3&rl=Y) 
and through permit conditions (as noted by the commenter, see https://www.tceq.texas.gov/assets/public/permitting/air/Guidance/NewSourceReview/mss/chem-mssdraftconditions.pdf) while Rule 1149 
contains the SCAMD degassing provisions (see https://www.aqmd.gov/docs/default-source/rule-book/reg-xi/rule-1149.pdf). The TAC requirements 
are the least stringent and require control of degassing emissions 
until the vapor space concentration is less than 35,000 ppmv as methane 
or 50 percent of the LEL. The Texas permit conditions require control 
of degassing emissions until the vapor space concentration is less than 
10 percent of the LEL or until the VOC concentration is less than 
10,000 ppmv and SCAQMD Rule 1149 requires control of degassing 
emissions until the vapor space concentration is less than 5,000 ppmv 
as methane. The Texas permit conditions requiring compliance with 10 
percent of the LEL and SCAQMD Rule 1149 control requirements are 
considered equivalent because 5,000 ppmv as methane equals 10 percent 
of the LEL for methane.
    Ethylene production facilities located in Texas are subject to 
maintenance, startup, and shutdown (MSS) special permit conditions, but 
no ethylene production facilities are subject to the SCAQMD rule. Of 
the 26 currently operating ethylene production facilities, 17 are in 
Texas. Therefore, the Texas permit conditions relying on storage vessel 
degassing until 10 percent of LEL is achieved reflect what the best 
performers have implemented for storage vessel degassing and we 
considered this information as the MACT floor for both new and existing 
sources. Notably, this also aligns with the commenter's assessment.
    We reviewed permit condition 6 (applicable to floating roof storage 
vessels) and permit condition 7 (applicable to fixed roof storage 
vessels) for key information that could be implemented to form the 
basis of a standard for storage vessel degassing that are required for 
facilities in Texas. The permit conditions require control of degassing 
emissions for floating roof and fixed roof storage vessels until the 
vapor space concentration is less than 10 percent of the LEL. The 
permit conditions also specify that facilities can also degas a storage 
vessel until they meet a VOC concentration of 10,000 ppmv, but we do 
not consider 10,000 ppmv to be equivalent to or as stringent as the 
compliance option to meet 10 percent of the LEL and are not including 
this as a compliance option. We also do not expect the best performers 
would be using this concentration for compliance, which is supported by 
the commenters recommending the requirements mimic the maintenance vent 
requirements and because the Texas permit conditions allow facilities 
to calibrate their LEL monitor using methane. Storage vessels may be 
vented to the atmosphere once the storage vessel degassing 
concentration threshold is met (i.e., less than 10 percent of the LEL) 
and all standing liquid has been removed from the vessel to the extent 
practicable. These requirements are considered MACT for both new and 
existing sources and we are finalizing these requirements at 40 CFR 
63.1103(e)(10).
    We calculated the impacts due to controlling storage vessel 
degassing emissions by evaluating the population of storage vessels 
that are subject to control under Table 7 at 40 CFR 63.1103(e)(3)(b) 
and (c) and not located in Texas. Storage vessels in the Ethylene 
Production source category in Texas would already be subject to the 
degassing requirements, and there would not be additional costs or 
emissions reductions for these facilities. Our review of the CAA 
section 114 ICR survey responses, showed that most storage vessels are 
seldom degassed, with an average of 14 years between degassing events. 
Based on this average and the population of storage vessels that are 
not in Texas, we estimated two storage vessel degassing events would be 
newly subject to control each year. Controlling storage vessel 
degassing would reduce HAP emissions by 1.7 tpy, with a total annual 
cost of $9,400. See the technical memoranda, Storage Vessel Degassing 
Model Development and Final Cost and Emissions Impacts for Ethylene 
Production NESHAP RTR, which are available in Docket ID No. EPA-HQ-OAR-
2017-0357 for details on the assumptions and methodologies used in this 
analysis.
    We also considered options BTF, but we did not identify any and are 
not aware of storage vessel degassing control provisions more stringent 
than those discussed above and being finalized in this rule, therefore, 
no BTF option was evaluated.
    Comment: We received comments in support of the proposed work 
practice standards for decoking operations. One commenter agreed with 
the EPA's conclusion to propose work practices for decoking operations 
pursuant to CAA section 112(h)(1) due to technological and economic 
limitations.
    However, another commenter stated that the proposed requirements 
for new and existing decoking operations failed to meet the 
requirements of CAA sections 112(d)(2) and (3). The commenter stated 
that the EPA correctly proposes to remove the general SSM exemptions, 
but instead proposes to regulate HAP emissions from decoking operations 
through work practice standards rather than emission limits, and 
includes four alternate actions for decoking of radiant tubes. The 
commenter asserted that the EPA may not set work practice standards 
unless it is ``not feasible to prescribe or enforce an emission 
standard.'' The commenter noted that the EPA provides no explanation or 
justification for why it chose four alternate practices, rather

[[Page 40412]]

than identifying the combination of practices that would eliminate HAP 
emissions, or reduce them to the furthest extent possible, consistent 
with CAA sections 112(d)(2) and (3). Additionally, the commenter stated 
that the EPA admits that the test data it collected from industry is 
unreliable, and inappropriately relies on this claim to posit that the 
Agency is entitled to promulgate a work practice standard. The 
commenter argued that the EPA's proposed standard is, therefore, 
inconsistent with the CAA's MACT requirements.
    Response: We agree with the commenters who state that work practice 
standards are appropriate for decoking operations due to technological 
and economic limitations. We are adopting these proposed work practice 
standards into the final rule with only minor changes, which are 
discussed elsewhere in rulemaking record (see the document, Summary of 
Public Comments and Responses for the Risk and Technology Review for 
Ethylene Production, which is available in Docket ID No. EPA-HQ-OAR-
2017-0357).
    We disagree that the work practice standards for decoking 
operations fail to meet the requirements of CAA sections 112(d)(2) and 
(3) and are inconsistent with the CAA's MACT requirements. As explained 
in the preamble to the proposed rule, we are adopting work practice 
standards instead of numeric emission limits as it is ``not feasible to 
prescribe or enforce an emission standard'' for these emissions because 
``the application of measurement technology to a particular class of 
sources is not practicable due to technological and economic 
limitations'' (see CAA section 112(h)(2)(B)). 84 FR 54307-309. The 
emissions stream generated from decoking operations (i.e., the 
combination of coke combustion constituents, air, and steam from the 
radiant tube(s)) is very dilute with a high moisture content (e.g., 
generally >95 percent water); and as explained in the preamble to the 
proposed rule, based on CAA section 114 ICR data, the majority of 
emissions measurements from the stream are not ``technologically 
practicable'' within the meaning of CAA section 112(h) because they are 
below detection limits. We have also previously reasoned that 
``application of measurement methodologies'' under CAA section 112(h) 
must also mean that a measurement has some reasonable relation to what 
the source is emitting (i.e., that the measurement yields a meaningful 
value). We have further explained that unreliable measurements raise 
issues of practicability, feasibility, and enforceability. 
Additionally, we have posited that the application of measurement 
methodology would also not be ``practicable due to . . . economic 
limitation'' within the meaning of CAA section 112(h) because it would 
result in cost expended to produce analytically suspect measurements. 
Refer to the Area Source Boiler Rule (75 FR 31906, June 4, 2010) and 
the NESHAP for the Wool Fiberglass Manufacturing source category (80 FR 
45280 and 45312, July 29, 2015).
    Moreover, the final rule, at 40 CFR 63.1103(e)(7), requires owners 
or operators to conduct daily inspections for flame impingement and 
also implement at least two of four other work practices to minimize 
coke combustion emissions from the decoking of the radiant tube(s) in 
each ethylene cracking furnace. Specifically, 40 CFR 63.1103(e)(7)(ii) 
through (v) requires owners or operators choose to conduct two of the 
following work practices: Monitor CO2 concentration, monitor 
temperature, purge the radiant tube(s), and/or apply material to the 
interior of the radiant tube(s)). In addition, the final rule, at 40 
CFR 63.1103(e)(8), requires owners or operators to conduct ethylene 
cracking furnace isolation valve inspections. With regard to the 
comment that the EPA provided no explanation or justification for why 
we chose the four other work practices, we believe each control measure 
is feasible and effective in reducing HAP emissions from decoking an 
ethylene cracking furnace. As explained in the preamble to the proposed 
rule (84 FR 54278, October 9, 2019), based on discussions with 
industry, as well as a review of facility-specific SSM plans that were 
submitted to the EPA in response to the CAA section 114 request, we 
determined that owners or operators already conduct work practices to 
minimize emissions due to coke combustion. We determined the measures 
to be consistent with CAA section 112(d) controls and reflect a level 
of performance analogous to a MACT floor; and we believe that it is 
most effective for sources to determine the best practices from the 
list of options. Regarding the comment as to unreliable data being used 
to support setting standards, as previously noted, the EPA typically 
has wide latitude in determining the extent of data-gathering necessary 
to solve a problem and courts generally defer to the agency's decision 
to proceed on the basis of imperfect scientific information, rather 
than to ``invest the resources to conduct the perfect study.'' Sierra 
Club v. EPA, 167 F. 3d 658, 662 (D.C. Cir. 1999)(If EPA were required 
to gather exhaustive data about a problem for which gathering such data 
is not yet feasible, the agency would be unable to act even if such 
inaction had potentially significant consequences . . . [A]n agency 
must make a judgment in the face of a known risk of unknown degree.'' 
Mexichem Specialty Resins, Inc., 787 F.3d. 561.).
4. What is the rationale for our final approach and final decisions for 
the revisions pursuant to CAA sections 112(d)(2) and (3)?
    We evaluated all of the comments on the EPA's proposed amendments 
to revisions for flares used as APCDs, clarifications for periods of 
SSM and bypasses, including PRD releases, bypass lines on closed vent 
systems, in situ sampling systems, maintenance activities, certain 
gaseous streams routed to a fuel gas system, and associated decoking 
operations for ethylene cracking furnaces (i.e., the decoking of 
ethylene cracking furnace radiant tubes). For the reasons explained in 
the proposed rule (84 FR 54278, October 9, 2019), we determined that 
the flare amendments are needed to ensure that flares used as APCD 
achieve the required level of MACT control and meet 98 percent 
destruction efficiency at all times as well as to ensure that CAA 
section 112 standards apply at all times. Similarly, the clarifications 
for periods of SSM and bypasses, including PRD releases, bypass lines 
on closed vent systems, in situ sampling systems, maintenance 
activities, certain gaseous streams routed to a fuel gas system, and 
work practice standards associated decoking operations for ethylene 
cracking furnaces are needed to be consistent with Sierra Club v. EPA, 
551 F.3d 1019 (D.C. Cir. 2008) to ensure that CAA section 112 standards 
apply at all times. More information and rationale concerning all the 
amendments we are finalizing pursuant to CAA sections 112(d)(2) and (3) 
is in the preamble to the proposed rule (84 FR 54278, October 9, 2019), 
section IV.B.3 of this preamble, and in the comments and our specific 
responses to the comments in the document, Summary of Public Comments 
and Responses for the Risk and Technology Reviews for the Ethylene 
Production Source Category, which is available in the docket for this 
action. Therefore, we are finalizing the proposed provisions for flares 
(except that we are not finalizing the work practice standard for 
velocity exceedances for flares operating above their smokeless 
capacity), finalizing the proposed clarifications for periods of

[[Page 40413]]

SSM and bypasses, including PRD releases, bypass lines on closed vent 
systems, in situ sampling systems, maintenance activities, certain 
gaseous streams routed to a fuel gas system, and finalizing the 
proposed work practice standards for the decoking of ethylene cracking 
furnaces with only minor editorial corrections and technical 
clarifications.

D. Amendments Addressing Emissions During Periods of SSM

1. What amendments did we propose to address emissions during periods 
of SSM?
    We proposed amendments to the EMACT standards to remove and revise 
provisions related to SSM that are not consistent with the requirement 
that the standards apply at all times. In a few instances, we are 
finalizing alternative standards for certain emission points during 
periods of SSM to ensure a continuous CAA section 112 standard applies 
``at all times,'' (see section IV.C); however for the majority of 
emission points in the Ethylene Production source category, we proposed 
eliminating the SSM exemptions and to have the MACT standards apply at 
all times. More information concerning the elimination of SSM 
provisions is in the preamble to the proposed rule (84 FR 54278, 
October 9, 2019).
2. How did the SSM provisions change since proposal?
    We are finalizing the SSM provisions as proposed (84 FR 54278, 
October 9, 2019) with only minor changes to 40 CFR 63.1103(e)(9) to 
sufficiently address the SSM exemption provisions from subparts 
referenced by the EMACT standards.
3. What key comments did we receive on the SSM revisions and what are 
our responses?
    While we are finalizing some alternative standards in this final 
rule for certain emission points during periods of SSM to ensure a 
continuous CAA section 112 standard applies ``at all times,'' (see 
section IV.C), we also proposed eliminating the SSM exemptions for the 
majority of emission points in the Ethylene Production source category. 
We did not receive many substantive comments on the removal of these 
exemptions; however, the comments and our specific responses to these 
items can be found in the document, Summary of Public Comments and 
Responses for the Risk and Technology Reviews for the Ethylene 
Production Source Category, available in the docket for this action.
4. What is the rationale for our final approach and final decisions to 
address emissions during periods of SSM?
    We evaluated all of the comments on the EPA's proposed amendments 
to the SSM provisions. For the reasons explained in the proposed rule 
(84 FR 54278, October 9, 2019), we determined that these amendments, 
which remove and revise provisions related to SSM, are necessary to be 
consistent with the requirement that the standards apply at all times. 
More information concerning the amendments we are finalizing for SSM is 
in the preamble to the proposed rule (84 FR 54278, October 9, 2019) and 
in the comments and our specific responses to the comments in the 
document, Summary of Public Comments and Responses for the Risk and 
Technology Reviews for the Ethylene Production Source Category, 
available in the docket for this action. Therefore, we are finalizing 
our approach for the SSM provisions as proposed.

E. Technical Amendments to the EMACT Standards

1. What other amendments did we propose for the Ethylene Production 
source category?
    We proposed that owners or operators submit electronic copies of 
required performance test results and reports and NOCS reports through 
the EPA's CDX using the CEDRI; and we proposed two broad circumstances 
in which we may provide extension to these requirements. We proposed at 
40 CFR 63.1110(a)(10)(iii) that an extension may be warranted due to 
outages of the EPA's CDX or CEDRI that precludes an owner or operator 
from accessing the system and submitting required reports. We also 
proposed at 40 CFR 63.1110(a)(10)(iv) that an extension may be 
warranted due to a force majeure event, such as an act of nature, act 
of war or terrorism, or equipment failure or safety hazards beyond the 
control of the facility.
    To correct a disconnect between having a NPDES permit that meets 
certain allowable discharge limits at the discharge point of a facility 
(e.g., outfall) and being able to adequately identify a leak, we 
proposed the removal of the exemption at 40 CFR 63.1084(c) for once-
through heat exchange systems to comply with 40 CFR 63.1085 and 40 CFR 
63.1086. We also proposed the removal of the exemption at 40 CFR 
63.1084(d) because the provision lacks the specificity of where a 
sample must be taken to adequately find and quantify a leak from a 
once-through heat exchange system.
    Further, to provide flexibility and reduce the burden on ethylene 
production facilities, we proposed overlap provisions at 40 CFR 
63.1100(g) allowing an owner or operator subject to both the equipment 
leak EMACT standards and 40 CFR part 60, subpart VVa to comply with the 
EMACT standards only (instead of complying with both standards), 
provided the owner or operator also complies with the calibration drift 
assessment provisions at 40 CFR 60.485a(b)(2).
    Finally, we proposed revisions for clarifying text or correcting 
typographical errors, grammatical errors, and cross-reference errors. 
These editorial corrections and clarifications are summarized in Table 
9 of the proposal. See 84 FR 54278, October 9, 2019.
2. How did the other amendments for the Ethylene Production source 
category change since proposal?
    Since proposal, the electronic reporting requirements and the 
technical and editorial corrections in Table 9 of the proposal (see 84 
FR 54278, October 9, 2019) have not changed and we are finalizing all 
the proposed requirements. Additionally, we are correcting an error in 
the final rule to clarify that Periodic Reports must also be submitted 
electronically (i.e., through the EPA's CDX website using the 
appropriate electronic report template for this subpart) beginning no 
later than the compliance dates specified in 40 CFR 63.1102(c) or once 
the report template has been available on the CEDRI website for at 
least 1 year, whichever date is later. We are also including several 
additional minor clarifying edits in the final rule based on comments 
received during the public comment period.
3. What key comments did we receive on the other amendments for the 
Ethylene Production source category and what are our responses?
    We did not receive many substantive comments on the other 
amendments in the Ethylene Production RTR proposal. These items 
generally include issues related to electronic reporting, removal of 
the allowance to use NPDES permits to identify leaks for heat exchange 
systems, overlap provisions for equipment leaks, and revisions that we 
proposed for clarifying text or correcting typographical errors, 
grammatical errors, and cross-reference errors. The comments and our 
specific responses to these items can be found in the document, Summary 
of Public Comments and Responses for the Risk and Technology Reviews 
for the

[[Page 40414]]

Ethylene Production Source Category, available in the docket for this 
action.
4. What is the rationale for our final approach and final decisions for 
the other amendments for the Ethylene Production source category?
    Based on the comments received for these other amendments, we are 
generally finalizing all proposed requirements. In a few instances 
(e.g., overlap provisions for equipment leaks), we received comments 
such that minor editorial corrections and technical clarifications are 
being made, and our rationale for these corrections and technical 
clarifications can be found in the document, Summary of Public Comments 
and Responses for the Risk and Technology Reviews for the Ethylene 
Production Source Category, available in the docket for this action.

V. Summary of Cost, Environmental, and Economic Impacts and Additional 
Analyses Conducted

A. What are the affected facilities?

    As of January 1, 2017, there were 26 ethylene production facilities 
currently operating that are major sources of HAP, and the EPA is aware 
of five ethylene production facilities under construction. As such, we 
estimate that 31 ethylene production facilities will be subject to the 
final amendments within the next 3 years. A complete list of facilities 
that are currently subject, or will be subject, to the EMACT standards 
is available in Appendix A of the memorandum, Review of the RACT/BACT/
LAER Clearinghouse Database for the Ethylene Production Source 
Category, in Docket ID No. EPA-HQ-OAR-2017-0357.

B. What are the air quality impacts?

V. Summary of Cost, Environmental, and Economic Impacts and Additional 
Analyses Conducted
    A. What are the affected facilities?
    As of January 1, 2017, there were 26 ethylene production facilities 
currently operating that are major sources of HAP, and the EPA is aware 
of five ethylene production facilities under construction. As such, we 
estimate that 31 ethylene production facilities will be subject to the 
final amendments within the next 3 years. A complete list of facilities 
that are currently subject, or will be subject, to the EMACT standards 
is available in Appendix A of the memorandum, Review of the RACT/BACT/
LAER Clearinghouse Database for the Ethylene Production Source 
Category, in Docket ID No. EPA-HQ-OAR-2017-0357.
    B. What are the air quality impacts?
    We estimate HAP emissions reductions of 29 tpy and VOC emissions 
reductions of 232 tpy as a result of the final amendments for storage 
vessels, heat exchange systems, and decoking operations for ethylene 
cracking furnaces. These emissions reductions do not consider the 
potential excess emissions reductions from flares that could result 
from the final monitoring requirements; we estimate flare excess 
emissions reductions of 1,430 tpy HAP and 13,020 tpy VOC. When 
considering the flare excess emissions, the total emissions reductions 
as a result of the final amendments are estimated at 1,459 tpy HAP and 
13,252 tpy VOC. These emissions reductions are documented in the 
following memoranda, which are available in Docket ID No. EPA-HQ-OAR-
2017-0357: Assessment of Work Practice Standards for Ethylene Cracking 
Furnace Decoking Operations Located in the Ethylene Production Source 
Category; Clean Air Act Section 112(d)(6) Technology Review for Heat 
Exchange Systems in the Ethylene Production Source Category; Control 
Option Impacts for Flares Located in the Ethylene Production Source 
Category; and Final Cost and Emissions Impacts for Ethylene Production 
NESHAP RTR.

C. What are the cost impacts?

    We estimate the total capital costs of the final amendments to be 
$47.2 million and the total annualized costs to be about $10.4 million 
in 2016 dollars (annualized costs include annual recovery credits of 
$180,000). The present value in 2020 of the costs is $87.5 million at a 
discount rate of 3 percent and $74.9 million at 7 percent. Calculated 
as an equivalent annualized value, which is consistent with the present 
value of costs, the costs are $9.4 million at a discount rate of 7 
percent and $10.9 million at a discount rate of 3 percent. These cost 
estimates are included in the memorandum, Economic Impact Analysis for 
Ethylene Production NESHAP RTR Final, which is available in the docket 
for this action. The costs are associated with the final amendments for 
flares, PRDs, maintenance (equipment openings), storage vessels, heat 
exchange systems, and decoking operations for ethylene cracking 
furnaces. Costs for flares include purchasing analyzers, monitors, 
natural gas and steam, developing a flare management plan, and 
performing root cause analysis and corrective action (details are 
available in the memorandum, Control Option Impacts for Flares Located 
in the Ethylene Production Source Category, in Docket ID No. EPA-HQ-
OAR-2017-0357). Costs for PRDs were developed based on compliance with 
the final work practice standard and include implementation of three 
prevention measures, performing root cause analysis and corrective 
action, and purchasing PRD monitors (details are available in the 
memorandum, Review of Regulatory Alternatives for Certain Vent Streams 
in the Ethylene Production Source Category, in Docket ID No. EPA-HQ-
OAR-2017-0357). Maintenance costs were estimated to document equipment 
opening procedures and to document circumstances under which the 
alternative maintenance vent limit is used (details are available in 
the memorandum, Review of Regulatory Alternatives for Certain Vent 
Streams in the Ethylene Production Source Category, in Docket ID No. 
EPA-HQ-OAR-2017-0357). Heat exchange systems costs include the use of 
the Modified El Paso Method to monitor for leaks (details are available 
in the memorandum, Clean Air Act Section 112(d)(6) Technology Review 
for Heat Exchange Systems in the Ethylene Production Source Category, 
in Docket ID No. EPA-HQ-OAR-2017-0357). The costs associated with 
decoking operations for ethylene cracking furnaces include conducting 
isolation valve inspections and conducting flame impingement firebox 
inspections (details are available in the memorandum, Assessment of 
Work Practice Standards for Ethylene Cracking Furnace Decoking 
Operations Located in the Ethylene Production Source Category, in 
Docket ID No. EPA-HQ-OAR-2017-0357). Costs for controlling storage 
vessel degassing emissions are discussed in the memorandum, Final Cost 
and Emissions Impacts for Ethylene Production NESHAP RTR, which is 
available in the docket for this action.

D. What are the economic impacts?

    The EPA conducted economic impact analyses for the amendments to 
the final rule, as detailed in the memorandum, Economic Impact Analysis 
for Ethylene Production NESHAP RTR Final, which is available in the 
docket for this action. The economic impacts of the amendments to the 
final rule are calculated as the percentage of total annualized costs 
incurred by affected parent owners to their annual revenues. This ratio 
of total annualized costs to annual revenues provides a measure of the 
direct economic impact to parent owners of ethylene production 
facilities while presuming no passthrough of costs to ethylene 
consumers. We estimate that none of the 16 parent owners affected by 
the amendments to the final rule will incur total annualized costs of 
0.02 percent or greater of their revenues. Of the 16 parent owners, 
none

[[Page 40415]]

of them is a small business according to the Small Business 
Administration's small business size standard (for NAICS 325110, 1,000 
employees or less). Product recovery, which is estimated as an impact 
of the final amendments, is included in the estimate of total 
annualized costs that is an input to the economic impact analysis. 
Thus, these economic impacts are quite low for affected companies and 
the ethylene production industry, and consumers of ethylene should 
experience minimal price changes.

E. What analysis of environmental justice did we conduct?

    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 practicable 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.
    To examine the potential for any environmental justice issues that 
might be associated with the source category, we performed a 
demographic analysis, which is an assessment of risks to individual 
demographic groups of the populations living within 5 kilometers (km) 
and within 50 km of the facilities. In the analysis, we evaluated the 
distribution of HAP-related cancer and noncancer risks from the 
Ethylene Production source category across different demographic groups 
within the populations living near facilities.
    Our analysis of the demographics of the population with estimated 
risks greater than 1-in-1 million indicates potential disparities in 
risks between demographic groups, including the African American, 
Hispanic or Latino, Over 25 Without a High School Diploma, and Below 
the Poverty Level groups. In addition, the population living within 50 
km of the ethylene production facilities has a higher percentage of 
minority, lower income, and lower education people when compared to the 
nationwide percentages of those groups. However, acknowledging these 
potential disparities, the risks for the source category were 
determined to be acceptable, and emissions reductions from the final 
amendments will benefit these groups the most.
    The methodology and the results of the demographic analysis are 
presented in a technical report, Risk and Technology Review--Analysis 
of Demographic Factors for Populations Living Near Ethylene Production 
Source Category Operations, available in the docket for this action.

F. What analysis of children's environmental health did we conduct?

    The EPA does not believe the environmental health or safety risks 
addressed by this action present a disproportionate risk to children. 
This action's health and risk assessments are summarized in section 
IV.A of this preamble and are further documented in the risk report, 
Residual Risk Assessment for the Ethylene Production Source Category in 
Support of the 2020 Risk and Technology Review Final Rule, available in 
the docket for this action.

VI. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

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

    This action is not a significant regulatory action and was, 
therefore, not submitted to the Office of Management and Budget (OMB) 
for review. The EPA prepared an analysis of the potential costs and 
benefits associated with this action. This analysis, Economic Impact 
Analysis for Ethylene Production NESHAP RTR Final, is available in the 
docket for this rule.

B. Executive Order 13771: Reducing Regulations and Controlling 
Regulatory Costs

    This action is not an Executive Order 13771 regulatory action 
because this action is not significant under Executive Order 12866.

C. Paperwork Reduction Act (PRA)

    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The ICR document that the 
EPA prepared has been assigned EPA ICR number 1983.10. The OMB Control 
Number is 2060-0489. You can find a copy of the ICR in the docket for 
this rule, and it is briefly summarized here. The information 
collection requirements are not enforceable until OMB approves them.
    We are finalizing amendments that change the reporting and 
recordkeeping requirements for several emission sources at ethylene 
production facilities (e.g., flares, decoking operations for ethylene 
cracking furnaces, heat exchangers, PRDs, storage vessels). The final 
amendments also require electronic reporting, remove the malfunction 
exemption, and impose other revisions that affect reporting and 
recordkeeping. This information would be collected to assure compliance 
with 40 CFR part 63, subparts XX and YY.
    Respondents/affected entities: Owners or operators of ethylene 
production facilities.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subparts XX and YY).
    Estimated number of respondents: 31 (total).
    Frequency of response: Semiannual and annual.
    Total estimated burden: 8,500 hours (per year). Burden is defined 
at 5 CFR 1320.3(b).
    Total estimated cost: $4,410,000 (per year), which includes 
$3,660,000 annualized capital or operation and maintenance costs.
    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. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities in this final rule.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. There are no 
small entities affected in this regulated industry. See the document, 
Economic Impact Analysis for Ethylene Production NESHAP RTR Final, 
available in the docket for this action.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. The action imposes 
no enforceable duty on any state, local, or tribal governments or the 
private sector.

F. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the

[[Page 40416]]

relationship between the national government and the states, or on the 
distribution of power and responsibilities among the various levels of 
government.

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

    This action does not have tribal implications as specified in 
Executive Order 13175. None of the ethylene production facilities that 
have been identified as being affected by this final action are owned 
or operated by tribal governments or located within tribal lands. Thus, 
Executive Order 13175 does not apply to this action.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children. This action's health and risk assessments are contained in 
sections IV.A of this preamble.

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

    This action is not subject to Executive Order 13211 because it is 
not a significant regulatory action under Executive Order 12866.

J. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR 
Part 51

    This rulemaking involves technical standards. As discussed in the 
preamble of the proposal, the EPA conducted searches for the EMACT 
standards through the Enhanced National Standards Systems Network 
Database managed by the American National Standards Institute (ANSI). 
We also contacted voluntary consensus standards (VCS) organizations and 
accessed and searched their databases. We conducted searches for EPA 
Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 3B, 4, 5, 18, 21, 22, 25, 25A, 
27, and 29 of 40 CFR part 60, appendix A, EPA Methods 301, 316, and 320 
of 40 CFR part 63, appendix A, and EPA Methods 602 and 624 of 40 CFR 
part 136, appendix A. During the 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 reviewed it as a potential equivalent method.
    The EPA incorporates by reference VCS ANSI/ASME PTC 19.10-1981 
(Part 10), ``Flue and Exhaust Gas Analyses,'' as an acceptable 
alternative to EPA Methods 3A and 3B for the manual procedures only and 
not the instrumental procedures. This method is used to quantitatively 
determine the gaseous constituents of exhausts including oxygen, 
CO2, carbon monoxide, nitrogen, sulfur dioxide, sulfur 
trioxide, nitric oxide, nitrogen dioxide, hydrogen sulfide, and 
hydrocarbons, and is available at the American National Standards 
Institute (ANSI), 1899 L Street NW, 11th floor, Washington, DC 20036 
and the American Society of Mechanical Engineers (ASME), Three Park 
Avenue, New York, NY 10016-5990. See https://wwww.ansi.org and https://www.asme.org.
    Also, the EPA incorporates by reference VCS ASTM D6420-18, 
``Standard Test Method for Determination of Gaseous Organic Compounds 
by Direct Interface Gas Chromatography-Mass Spectrometry,'' as an 
acceptable alternative to EPA Method 18 with the following caveats. 
This ASTM procedure uses a direct interface gas chromatograph/mass 
spectrometer to identify and quantify VOC and has been approved by the 
EPA as an alternative to EPA Method 18 only when the target compounds 
are all known and the target compounds are all listed in ASTM D6420-18 
as measurable. ASTM D6420-18 should not be used for methane and ethane 
because the atomic mass is less than 35; and ASTM D6420-18 should never 
be specified as a total VOC method.
    In addition, the EPA incorporates by reference VCS ASTM D6348-12e1, 
``Determination of Gaseous Compounds by Extractive Direct Interface 
Fourier Transform (FTIR) Spectroscopy,'' as an acceptable alternative 
to EPA Method 320 with caveats requiring inclusion of selected annexes 
to the standard as mandatory. This ASTM procedure uses an extractive 
sampling system that routes stationary source effluent to an FTIR 
spectrometer for the identification and quantification of gaseous 
compounds. The test plan preparation and implementation in the Annexes 
to ASTM D 6348-03, Sections A1 through A8 are mandatory; therefore, the 
EPA incorporates by reference, ``Standard Test Method for Determination 
of Gaseous Compounds by Extractive Direct Interface Fourier Transform 
Infrared (FTIR) Spectroscopy.'' This ASTM procedure also uses an 
extractive sampling system and FTIR spectrometer for the identification 
and quantification of gaseous compounds. The percent (%) R must be 
determined for each target analyte (Equation A5.5) when using ASTM 
D6348-03, Annex A5 (Analyte Spiking Technique). In order for the test 
data to be acceptable for a compound, %R must be 70% >= R <= 130%. If 
the %R value does not meet this criterion for a target compound, the 
test data is not acceptable for that compound and the test must be 
repeated for that analyte (i.e., the sampling and/or analytical 
procedure should be adjusted before a retest). The %R value for each 
compound must be reported in the test report, and all field 
measurements must be corrected with the calculated %R value for that 
compound by using the following equation:

Reported Results = (Measured Concentration in the Stack x 100)/%R.

    The three ASTM methods (ASTM D6420-18, ASTM D6348-12e1, and ASTM D 
6348-03) newly incorporated by reference in this rule are available to 
the public for free viewing online in the Reading Room section on 
ASTM's website at https://www.astm.org/READINGLIBRARY/. In addition to 
this free online viewing availability on ASTM's website, hard copies 
and printable versions are available for purchase from ASTM at https://www.astm.org/.
    Also, the EPA decided not to include 17 other VCS; these methods 
are impractical as alternatives because of the lack of equivalency, 
documentation, validation date, and other important technical and 
policy considerations. The search and review results have been 
documented and are in the memorandum, Voluntary Consensus Standard 
Results for National Emission Standards for Hazardous Air Pollutants 
for Ethylene Production RTR, which is available in the docket for this 
action.
    Under 40 CFR 63.7(f) and 40 CFR 63.8(f) (in subpart A--General 
Provisions), a source may apply to the EPA for permission to use 
alternative test methods or alternative monitoring requirements in 
place of any required testing methods, performance specifications, or 
procedures in the final rule or any amendments.
    Finally, although not considered a VCS, the EPA incorporates by 
reference, ``Volatile Organic Compounds by Gas Chromatography/Mass 
Spectrometry (GC/MS)'' (SW-846-8260B) and ``Semivolatile Organic 
Compounds by Gas Chromatography/Mass Spectrometry (GC/MS)'' (SW-846-
8270D) into 40 CFR 63.1107(a); and ``Air Stripping Method (Modified El 
Paso

[[Page 40417]]

Method) for Determination of Volatile Organic Compound Emissions from 
Water Sources,'' into 40 CFR 63.1086(e) and 40 CFR 63.1089(d). Each of 
these methods is used to identify organic HAP in water; however, SW-
846-8260B and SW-846-8270D use water sampling techniques and the 
Modified El Paso Method uses an air stripping sampling technique. The 
SW-846 methods are available from the EPA at https://www.epa.gov/hw-sw846 while the Modified El Paso Method is available from TCEQ at 
https://www.tceq.texas.gov/assets/public/compliance/field_ops/guidance/samplingappp.pdf.

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

    The EPA believes that this action does not have disproportionately 
high and adverse human health or environmental effects on minority 
populations, low-income populations, and/or indigenous peoples, as 
specified in Executive Order 12898 (59 FR 7629, February 16, 1994).
    The documentation for this decision is contained in section IV.A of 
this preamble and in the technical report, Risk and Technology Review--
Analysis of Demographic Factors for Populations Living Near Ethylene 
Production Source Category Operations, available in the docket for this 
action.

L. Congressional Review Act (CRA)

    This action is subject to the CRA, and the EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects in 40 CFR Part 63

    Environmental protection, Administrative practice and procedures, 
Air pollution control, Hazardous substances, Incorporation by 
reference, Intergovernmental relations, Reporting and recordkeeping 
requirements.

    Dated: March 12, 2020.
Andrew R. Wheeler,
Administrator.

    For the reasons set forth in the preamble, the EPA is amending 40 
CFR part 63 as follows:

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

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

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

Subpart A--General Provisions

0
2. Section 63.14 is amended by:
0
a. Revising paragraphs (e)(1) and (h)(18), (83), and (85);
0
b. Redesignating paragraphs (h)(92) through (112) as paragraphs (h)(93) 
through (113);
0
c. Adding new paragraph (h)(92);
0
d. Revising paragraphs (n)(12) and (13); and
0
e. Revising paragraph (t)(1).
    The revisions and addition read as follows:


Sec.  63.14  Incorporations by reference.

* * * * *
    (e) * * *
    (1) ANSI/ASME PTC 19.10-1981, Flue and Exhaust Gas Analyses [Part 
10, Instruments and Apparatus], issued August 31, 1981, IBR approved 
for Sec. Sec.  63.309(k), 63.457(k), 63.772(e) and (h), 63.865(b), 
63.997(e), 63.1282(d) and (g), 63.1625(b), 63.3166(a), 63.3360(e), 
63.3545(a), 63.3555(a), 63.4166(a), 63.4362(a), 63.4766(a), 63.4965(a), 
63.5160(d), table 4 to subpart UUUU, table 3 to subpart YYYY, 
63.9307(c), 63.9323(a), 63.11148(e), 63.11155(e), 63.11162(f), 
63.11163(g), 63.11410(j), 63.11551(a), 63.11646(a), and 63.11945, table 
5 to subpart DDDDD, table 4 to subpart JJJJJ, table 4 to subpart KKKKK, 
tables 4 and 5 of subpart UUUUU, table 1 to subpart ZZZZZ, and table 4 
to subpart JJJJJJ.
* * * * *
    (h) * * *
    (18) ASTM D1946-90 (Reapproved 1994), Standard Method for Analysis 
of Reformed Gas by Gas Chromatography, 1994, IBR approved for 
Sec. Sec.  63.11(b), 63.987(b), and 63.1412.
* * * * *
    (83) ASTM D6348-03, Standard Test Method for Determination of 
Gaseous Compounds by Extractive Direct Interface Fourier Transform 
Infrared (FTIR) Spectroscopy, including Annexes A1 through A8, Approved 
October 1, 2003, IBR approved for Sec. Sec.  63.457(b), 63.997(e), and 
63.1349, table 4 to subpart DDDD, table 4 to subpart UUUU, table 4 
subpart ZZZZ, and table 8 to subpart HHHHHHH.
* * * * *
    (85) ASTM D6348-12e1, Standard Test Method for Determination of 
Gaseous Compounds by Extractive Direct Interface Fourier Transform 
Infrared (FTIR) Spectroscopy, Approved February 1, 2012, IBR approved 
for Sec. Sec.  63.997(e) and 63.1571(a) and Table 4 to subpart UUUU.
* * * * *
    (92) ASTM D6420-18, Standard Test Method for Determination of 
Gaseous Organic Compounds by Direct Interface Gas Chromatography-Mass 
Spectrometry, Approved November 1, 2018, IBR approved for Sec.  
63.987(b) and Sec.  63.997(e).
* * * * *
    (n) * * *
    (12) SW-846-8260B, Volatile Organic Compounds by Gas 
Chromatography/Mass Spectrometry (GC/MS), Revision 2, December 1996, in 
EPA Publication No. SW-846, Test Methods for Evaluating Solid Waste, 
Physical/Chemical Methods, Third Edition, IBR approved for Sec. Sec.  
63.1107(a), 63.11960, 63.11980, and table 10 to subpart HHHHHHH.
    (13) SW-846-8270D, Semivolatile Organic Compounds by Gas 
Chromatography/Mass Spectrometry (GC/MS), Revision 4, February 2007, in 
EPA Publication No. SW-846, Test Methods for Evaluating Solid Waste, 
Physical/Chemical Methods, Third Edition, IBR approved for Sec. Sec.  
63.1107(a), 63.11960, 63.11980, and table 10 to subpart HHHHHHH.
* * * * *
    (t) * * *
    (1) ``Air Stripping Method (Modified El Paso Method) for 
Determination of Volatile Organic Compound Emissions from Water 
Sources,'' Revision Number One, dated January 2003, Sampling Procedures 
Manual, Appendix P: Cooling Tower Monitoring, January 31, 2003, IBR 
approved for Sec. Sec.  63.654(c) and (g), 63.655(i), 63.1086(e), 
63.1089(d), and 63.11920.
* * * * *

Subpart SS--National Emission Standards for Closed Vent Systems, 
Control Devices, Recovery Devices and Routing to a Fuel Gas System 
or a Process

0
3. Section 63.987 is amended by revising parameter ``Dj'' of Equation 1 
in paragraph (b)(3)(ii) to read as follows:


Sec.  63.987   Flare requirements.

* * * * *
    (b) * * *
    (3) * * *
    (ii) * * *
* * * * *
Dj = Concentration of sample component j, in parts per million by 
volume on a wet basis, as measured for organics by Method 18 of 40 CFR 
part 60, appendix A, or by ASTM D6420-18 (incorporated by reference, 
see Sec.  63.14) under the conditions specified in Sec.  
63.997(e)(2)(iii)(D)(1) through (3). Hydrogen and carbon monoxide are 
measured by ASTM D1946-90

[[Page 40418]]

(Reapproved 1994) (incorporated by reference, see Sec.  63.14); and
* * * * *

0
4. Section 63.997 is amended by revising paragraphs (e)(2)(iii) 
introductory text, (e)(2)(iii)(C)(1), (e)(2)(iii)(D), (e)(2)(iv) 
introductory text, and (e)(2)(iv)(F) and (I) to read as follows:


Sec.  63.997  Performance test and compliance assessment requirements 
for control devices.

* * * * *
    (e) * * *
    (2) * * *
    (iii) Total organic regulated material or TOC concentration. To 
determine compliance with a parts per million by volume total organic 
regulated material or TOC limit, the owner or operator shall use Method 
18 or 25A of 40 CFR part 60, appendix A, as applicable. The ASTM D6420-
18 (incorporated by reference, see Sec.  63.14) may be used in lieu of 
Method 18 of 40 CFR part 60, appendix A, under the conditions specified 
in paragraphs (e)(2)(iii)(D)(1) through (3) of this section. 
Alternatively, any other method or data that have been validated 
according to the applicable procedures in Method 301 of appendix A to 
this part may be used. The procedures specified in paragraphs 
(e)(2)(iii)(A), (B), (D), and (E) of this section shall be used to 
calculate parts per million by volume concentration. The calculated 
concentration shall be corrected to 3 percent oxygen using the 
procedures specified in paragraph (e)(2)(iii)(C) of this section if a 
combustion device is the control device and supplemental combustion air 
is used to combust the emissions.
* * * * *
    (C) * * *
    (1) The emission rate correction factor (or excess air), integrated 
sampling and analysis procedures of Method 3B of 40 CFR part 60, 
appendix A, or the manual method in ANSI/ASME PTC 19.10-1981--Part 10 
(incorporated by reference, see Sec.  63.14), shall be used to 
determine the oxygen concentration. The sampling site shall be the same 
as that of the organic regulated material or organic compound samples, 
and the samples shall be taken during the same time that the organic 
regulated material or organic compound samples are taken.
* * * * *
    (D) To measure the total organic regulated material concentration 
at the outlet of a control device, use Method 18 of 40 CFR part 60, 
appendix A, or ASTM D6420-18 (incorporated by reference, see Sec.  
63.14). If you have a combustion control device, you must first 
determine which regulated material compounds are present in the inlet 
gas stream using process knowledge or the screening procedure described 
in Method 18. In conducting the performance test, analyze samples 
collected at the outlet of the combustion control device as specified 
in Method 18 or ASTM D6420-18 for the regulated material compounds 
present at the inlet of the control device. The method ASTM D6420-18 
may be used only under the conditions specified in paragraphs 
(e)(2)(iii)(D)(1) through (3) of this section.
    (1) If the target compounds are all known and are all listed in 
Section 1.1 of ASTM D6420-18 as measurable.
    (2) ASTM D6420-18 may not be used for methane and ethane.
    (3) ASTM D6420-18 may not be used as a total VOC method.
* * * * *
    (iv) Percent reduction calculation. To determine compliance with a 
percent reduction requirement, the owner or operator shall use Method 
18, 25, or 25A of 40 CFR part 60, appendix A, as applicable. The method 
ASTM D6420-18 (incorporated by reference, see Sec.  63.14) may be used 
in lieu of Method 18 of 40 CFR part 60, appendix A, under the 
conditions specified in paragraphs (e)(2)(iii)(D)(1) through (3) of 
this section. Alternatively, any other method or data that have been 
validated according to the applicable procedures in Method 301 of 
appendix A to this part may be used. The procedures specified in 
paragraphs (e)(2)(iv)(A) through (I) of this section shall be used to 
calculate percent reduction efficiency.
* * * * *
    (F) To measure inlet and outlet concentrations of total organic 
regulated material, use Method 18 of 40 CFR part 60, appendix A, or 
ASTM D6420-18 (incorporated by reference, see Sec.  63.14), under the 
conditions specified in paragraphs (e)(2)(iii)(D)(1) through (3) of 
this section. In conducting the performance test, collect and analyze 
samples as specified in Method 18 or ASTM D6420-18. You must collect 
samples simultaneously at the inlet and outlet of the control device. 
If the performance test is for a combustion control device, you must 
first determine which regulated material compounds are present in the 
inlet gas stream (i.e., uncontrolled emissions) using process knowledge 
or the screening procedure described in Method 18. Quantify the 
emissions for the regulated material compounds present in the inlet gas 
stream for both the inlet and outlet gas streams for the combustion 
device.
* * * * *
    (I) If the uncontrolled or inlet gas stream to the control device 
contains formaldehyde, you must conduct emissions testing according to 
paragraphs (e)(2)(iv)(I)(1) through (3) of this section.
    (1) Except as specified in paragraph (e)(2)(iv)(I)(3) of this 
section, if you elect to comply with a percent reduction requirement 
and formaldehyde is the principal regulated material compound (i.e., 
greater than 50 percent of the regulated material compounds in the 
stream by volume), you must use Method 316 or 320 of appendix A to this 
part, to measure formaldehyde at the inlet and outlet of the control 
device. Use the percent reduction in formaldehyde as a surrogate for 
the percent reduction in total regulated material emissions.
    (2) Except as specified in paragraph (e)(2)(iv)(I)(3) of this 
section, if you elect to comply with an outlet total organic regulated 
material concentration or TOC concentration limit, and the uncontrolled 
or inlet gas stream to the control device contains greater than 10 
percent (by volume) formaldehyde, you must use Method 316 or 320 of 
appendix A to this part, to separately determine the formaldehyde 
concentration. Calculate the total organic regulated material 
concentration or TOC concentration by totaling the formaldehyde 
emissions measured using Method 316 or 320 and the other regulated 
material compound emissions measured using Method 18 or 25/25A of 40 
CFR part 60, appendix A.
    (3) You may elect to use ASTM D6348-12e1 (incorporated by 
reference, Sec.  63.14) in lieu of Method 316 or 320 of appendix A to 
this part as specified in paragraph (e)(2)(iv)(I)(1) or (2) of this 
section. To comply with this paragraph, the test plan preparation and 
implementation in the Annexes to ASTM D6348-03 (incorporated by 
reference, see Sec.  63.14) Sections Al through A8 are mandatory; the 
percent (%) R must be determined for each target analyte using Equation 
A5.5 of ASTM D6348-03 Annex A5 (Analyte Spiking Technique); and in 
order for the test data to be acceptable for a compound, the %R must be 
70% >= R <= 130%. If the %R value does not meet this criterion for a 
target compound, then the test data is not acceptable for that compound 
and the test must be repeated for that analyte (i.e., the sampling and/
or analytical procedure should be adjusted before a retest). The %R 
value for each compound must be

[[Page 40419]]

reported in the test report, and all field measurements must be 
corrected with the calculated %R value for that compound by using the 
following equation:

Reported Results = (Measured Concentration in the Stack x 100)/%R.

Subpart XX--National Emission Standards for Ethylene Manufacturing 
Process Units: Heat Exchange Systems and Waste Operations

0
5. Section 63.1081 is revised to read as follows:


Sec.  63.1081   When must I comply with the requirements of this 
subpart?

    You must comply with the requirements of this subpart according to 
the schedule specified in Sec.  63.1102(a). Each heat exchange system 
which is part of an ethylene production affected source also must 
comply with paragraph (a) of this section. Each waste stream which is 
part of an ethylene production affected source also must comply with 
paragraph (b) of this section.
    (a) Each heat exchange system that is part of an ethylene 
production affected source that commenced construction or 
reconstruction on or before October 9, 2019, must be in compliance with 
the heat exchange system requirements specified in Sec. Sec.  
63.1084(f), 63.1085(e) and (f), 63.1086(e), 63.1087(c) and (d), 
63.1088(d), and 63.1089(d) and (e) upon initial startup or July 6, 
2023, whichever is later. Each heat exchange system that is part of an 
ethylene production affected source that commences construction or 
reconstruction after October 9, 2019, must be in compliance with the 
heat exchange system requirements specified in Sec. Sec.  63.1084(f), 
63.1085(e) and (f), 63.1086(e), 63.1087(c) and (d), 63.1088(d), and 
63.1089(d) and (e) upon initial startup, or July 6, 2020, whichever is 
later.
    (b) Each waste stream that is part of an ethylene production 
affected source that commenced construction or reconstruction on or 
before October 9, 2019, must be in compliance with the flare 
requirements specified in Sec.  63.1095(a)(1)(vi) and (b)(3) upon 
initial startup or July 6, 2023, whichever is later. Each waste stream 
that is part of an ethylene production affected source that commences 
construction or reconstruction after October 9, 2019, must be in 
compliance with the flare requirements specified in Sec.  
63.1095(a)(1)(vi) and (b)(3) upon initial startup, or July 6, 2020, 
whichever is later.

0
6. Section 63.1082 is amended in paragraph (b) by revising definitions 
for ``Dilution steam blowdown waste stream,'' and ``Spent caustic waste 
stream'' to read as follows:


Sec.  63.1082  What definitions do I need to know?

* * * * *
    (b) * * *
    Dilution steam blowdown waste stream means any continuously flowing 
process wastewater stream resulting from the quench and compression of 
cracked gas (the cracking furnace effluent) at an ethylene production 
unit and is discharged from the unit. This stream typically includes 
the aqueous or oily-water stream that results from condensation of 
dilution steam (in the cracking furnace quench system), blowdown from 
dilution steam generation systems, and aqueous streams separated from 
the process between the cracking furnace and the cracked gas 
dehydrators. The dilution steam blowdown waste stream does not include 
blowdown that has not contacted HAP-containing process materials. 
Before July 6, 2023, the dilution steam blowdown waste stream does not 
include dilution steam blowdown streams generated from sampling, 
maintenance activities, or shutdown purges. Beginning on July 6, 2023, 
the dilution steam blowdown streams generated from sampling, 
maintenance activities, or shutdown purges are included in the 
definition of dilution steam blowdown waste stream.
* * * * *
    Spent caustic waste stream means the continuously flowing process 
wastewater stream that results from the use of a caustic wash system in 
an ethylene production unit. A caustic wash system is commonly used at 
ethylene production units to remove acid gases and sulfur compounds 
from process streams, typically cracked gas. Before July 6, 2023, the 
spent caustic waste stream does not include spent caustic streams 
generated from sampling, maintenance activities, or shutdown purges. 
Beginning on July 6, 2023, the spent caustic streams generated from 
sampling, maintenance activities, or shutdown purges are included in 
the definition of spent caustic waste stream.

0
7. Section 63.1084 is amended by revising the introductory text and 
adding paragraph (f) to read as follows:


Sec.  63.1084  What heat exchange systems are exempt from the 
requirements of this subpart?

    Except as specified in paragraph (f) of this section, your heat 
exchange system is exempt from the requirements in Sec. Sec.  63.1085 
and 63.1086 if it meets any one of the criteria in paragraphs (a) 
through (e) of this section.
* * * * *
    (f) Beginning no later than the compliance dates specified in Sec.  
63.1081(a), your heat exchange system is no longer exempt from the 
requirements in Sec. Sec.  63.1085 and 63.1086 if it meets the criteria 
in paragraph (c) or (d) of this section; instead, your heat exchange 
system is exempt from the requirements in Sec. Sec.  63.1085 and 
63.1086 if it meets any one of the criteria in paragraph (a), (b), or 
(e) of this section.

0
8. Section 63.1085 is amended by revising the introductory text and 
paragraphs (a) and (b) and by adding paragraphs (e) and (f) to read as 
follows:


Sec.  63.1085  What are the general requirements for heat exchange 
systems?

    Unless you meet one of the requirements for exemptions in Sec.  
63.1084, you must meet the requirements in paragraphs (a) through (f) 
of this section.
    (a) Except as specified in paragraph (e) of this section, you must 
monitor the cooling water for the presence of substances that indicate 
a leak according to Sec.  63.1086(a) through (d).
    (b) Except as specified in paragraph (f) of this section, if you 
detect a leak, then you must repair it according to Sec.  63.1087(a) 
and (b) unless repair is delayed according to Sec.  63.1088(a) through 
(c).
* * * * *
    (e) Beginning no later than the compliance dates specified in Sec.  
63.1081(a), the requirements specified in Sec.  63.1086(a) through (d) 
no longer apply; instead, you must monitor the cooling water for the 
presence of total strippable hydrocarbons that indicate a leak 
according to Sec.  63.1086(e). At any time before the compliance dates 
specified in Sec.  63.1081(a), you may choose to comply with the 
requirements in this paragraph in lieu of the requirements in paragraph 
(a) of this section.
    (f) Beginning no later than the compliance dates specified in Sec.  
63.1081(a), the requirements specified in Sec. Sec.  63.1087(a) and (b) 
and 63.1088(a) through (c), no longer apply; instead, if you detect a 
leak, then you must repair it according to Sec.  63.1087(c) and (d), 
unless repair is delayed according to Sec.  63.1088(d). At any time 
before the compliance dates specified in Sec.  63.1081(a), you may 
choose to comply with the requirements in this paragraph in lieu of the 
requirements in paragraph (b) of this section.

[[Page 40420]]


0
9. Section 63.1086 is amended by revising the introductory text and by 
adding paragraph (e) to read as follows:


Sec.  63.1086  How must I monitor for leaks to cooling water?

    Except as specified in Sec.  63.1085(e) and paragraph (e) of this 
section, you must monitor for leaks to cooling water by monitoring each 
heat exchange system according to the requirements of paragraph (a) of 
this section, monitoring each heat exchanger according to the 
requirements of paragraph (b) of this section, or monitoring a 
surrogate parameter according to the requirements of paragraph (c) of 
this section. Except as specified in Sec.  63.1085(e) and paragraph (e) 
of this section, if you elect to comply with the requirements of 
paragraph (a) or (b) of this section, you may use alternatives in 
paragraph (d)(1) or (2) of this section for determining the mean 
entrance concentration.
* * * * *
    (e) Beginning no later than the compliance dates specified in Sec.  
63.1081(a), you must perform monitoring to identify leaks of total 
strippable hydrocarbons from each heat exchange system subject to the 
requirements of this subpart according to the procedures in paragraphs 
(e)(1) through (5) of this section.
    (1) Monitoring locations for closed-loop recirculation heat 
exchange systems. For each closed loop recirculating heat exchange 
system, you must collect and analyze a sample from the location(s) 
described in either paragraph (e)(1)(i) or (ii) of this section.
    (i) Each cooling tower return line or any representative riser 
within the cooling tower prior to exposure to air for each heat 
exchange system.
    (ii) Selected heat exchanger exit line(s), so that each heat 
exchanger or group of heat exchangers within a heat exchange system is 
covered by the selected monitoring location(s).
    (2) Monitoring locations for once-through heat exchange systems. 
For each once-through heat exchange system, you must collect and 
analyze a sample from the location(s) described in paragraph (e)(2)(i) 
of this section. You may also elect to collect and analyze an 
additional sample from the location(s) described in paragraph 
(e)(2)(ii) of this section.
    (i) Selected heat exchanger exit line(s), so that each heat 
exchanger or group of heat exchangers within a heat exchange system is 
covered by the selected monitoring location(s). The selected monitoring 
location may be at a point where discharges from multiple heat exchange 
systems are combined provided that the combined cooling water flow rate 
at the monitoring location does not exceed 165,000 gallons per minute.
    (ii) The inlet water feed line for a once-through heat exchange 
system prior to any heat exchanger. If multiple heat exchange systems 
use the same water feed (i.e., inlet water from the same primary water 
source), you may monitor at one representative location and use the 
monitoring results for that sampling location for all heat exchange 
systems that use that same water feed.
    (3) Monitoring method. If you comply with the total strippable 
hydrocarbon concentration leak action level as specified in paragraph 
(e)(4) of this section, you must comply with the requirements in 
paragraph (e)(3)(i) of this section. If you comply with the total 
hydrocarbon mass emissions rate leak action level as specified in 
paragraph (e)(4) of this section, you must comply with the requirements 
in paragraphs (e)(3)(i) and (ii) of this section.
    (i) You must determine the total strippable hydrocarbon 
concentration (in parts per million by volume (ppmv) as methane) at 
each monitoring location using the ``Air Stripping Method (Modified El 
Paso Method) for Determination of Volatile Organic Compound Emissions 
from Water Sources'' (incorporated by reference, see Sec.  63.14) using 
a flame ionization detector analyzer for on-site determination as 
described in Section 6.1 of the Modified El Paso Method.
    (ii) You must convert the total strippable hydrocarbon 
concentration (in ppmv as methane) to a total hydrocarbon mass 
emissions rate (as methane) using the calculations in Section 7.0 of 
``Air Stripping Method (Modified El Paso Method) for Determination of 
Volatile Organic Compound Emissions from Water Sources'' (incorporated 
by reference--see Sec.  63.14).
    (4) Monitoring frequency and leak action level. For each heat 
exchange system, you must comply with the applicable monitoring 
frequency and leak action level, as defined in paragraphs (e)(4)(i) 
through (iii) of this section. The monitoring frequencies specified in 
paragraphs (e)(4)(i) through (iii) of this section also apply to the 
inlet water feed line for a once-through heat exchange system, if you 
elect to monitor the inlet water feed as provided in paragraph 
(e)(2)(ii) of this section.
    (i) For each heat exchange system that is part of an ethylene 
production affected source that commenced construction or 
reconstruction on or before December 6, 2000, you must monitor 
quarterly using a leak action level defined as a total strippable 
hydrocarbon concentration (as methane) in the stripping gas of 6.2 ppmv 
or, for heat exchange systems with a recirculation rate of 10,000 
gallons per minute or less, you may monitor quarterly using a leak 
action level defined as a total hydrocarbon mass emissions rate from 
the heat exchange system (as methane) of 0.18 kg/hr. If a leak is 
detected as specified in paragraph (e)(5) of this section, then you 
must monitor monthly until the leak has been repaired according to the 
requirements in Sec.  63.1087(c) or (d). Once the leak has been 
repaired according to the requirements in Sec.  63.1087(c) or (d), 
quarterly monitoring for the heat exchange system may resume.
    (ii) For each heat exchange system that is part of an ethylene 
production affected source that commences construction or 
reconstruction after December 6, 2000 and on or before October 9, 2019, 
you must monitor at the applicable frequency specified in paragraph 
(e)(4)(ii)(A) or (B) of this section using a leak action level defined 
as a total strippable hydrocarbon concentration (as methane) in the 
stripping gas of 6.2 ppmv or, for heat exchange systems with a 
recirculation rate of 10,000 gallons per minute or less, you may 
monitor at the applicable frequency specified in paragraph 
(e)(4)(ii)(A) or (B) of this section using a leak action level defined 
as a total hydrocarbon mass emissions rate from the heat exchange 
system (as methane) of 0.18 kg/hr.
    (A) If you have completed the initial weekly monitoring for 6-
months of the heat exchange system as specified in Sec.  
63.1086(a)(2)(ii) or (b)(1)(ii) then you must monitor monthly. If a 
leak is detected as specified in paragraph (e)(5) of this section, then 
you must monitor weekly until the leak has been repaired according to 
the requirements in Sec.  63.1087(c) or (d). Once the leak has been 
repaired according to the requirements in Sec.  63.1087(c) or (d), 
monthly monitoring for the heat exchange system may resume.
    (B) If you have not completed the initial weekly monitoring for 6-
months of the heat exchange system as specified in Sec.  
63.1086(a)(2)(ii) or (b)(1)(ii), or if you elect to comply with 
paragraph (e) of this section rather than paragraphs (a) through (d) of 
this section upon startup, then you must initially monitor weekly for 
6-months beginning upon startup and monitor monthly thereafter. If a 
leak is detected as specified in paragraph (e)(5) of this section, then 
you must monitor weekly until the leak has been repaired according to 
the requirements in Sec.  63.1087(c) or (d). Once the leak has

[[Page 40421]]

been repaired according to the requirements in Sec.  63.1087(c) or (d), 
monthly monitoring for the heat exchange system may resume.
    (iii) For each heat exchange system that is part of an ethylene 
production affected source that commences construction or 
reconstruction after October 9, 2019, you must initially monitor weekly 
for 6-months beginning upon startup and monitor monthly thereafter 
using a leak action level defined as a total strippable hydrocarbon 
concentration (as methane) in the stripping gas of 6.2 ppmv or, for 
heat exchange systems with a recirculation rate of 10,000 gallons per 
minute or less, you may use a leak action level defined as a total 
hydrocarbon mass emissions rate from the heat exchange system (as 
methane) of 0.18 kg/hr if the heat exchange system has a recirculation 
rate of 10,000 gallons per minute or less. If a leak is detected as 
specified in paragraph (e)(5) of this section, then you must monitor 
weekly until the leak has been repaired according to the requirements 
in Sec.  63.1087(c) or (d). Once the leak has been repaired according 
to the requirements in Sec.  63.1087(c) or (d), monthly monitoring for 
the heat exchange system may resume.
    (5) Leak definition. A leak is defined as described in paragraph 
(e)(5)(i) or (ii) of this section, as applicable.
    (i) For once-through heat exchange systems for which the inlet 
water feed is monitored as described in paragraph (e)(2)(ii) of this 
section, a leak is detected if the difference in the measurement value 
of the sample taken from a location specified in paragraph (e)(2)(i) of 
this section and the measurement value of the corresponding sample 
taken from the location specified in paragraph (e)(2)(ii) of this 
section equals or exceeds the leak action level.
    (ii) For all other heat exchange systems, a leak is detected if a 
measurement value of the sample taken from a location specified in 
paragraph (e)(1)(i), (ii), or (e)(2)(i) of this section equals or 
exceeds the leak action level.

0
10. Section 63.1087 is amended by revising the introductory text and by 
adding paragraphs (c) and (d) to read as follows:


Sec.  63.1087   What actions must I take if a leak is detected?

    Except as specified in Sec.  63.1085(f) and paragraphs (c) and (d) 
of this section, if a leak is detected, you must comply with the 
requirements in paragraphs (a) and (b) of this section unless repair is 
delayed according to Sec.  63.1088.
* * * * *
    (c) Beginning no later than the compliance dates specified in Sec.  
63.1081(a), if a leak is detected using the methods described in Sec.  
63.1086(e), you must repair the leak to reduce the concentration or 
mass emissions rate to below the applicable leak action level as soon 
as practicable, but no later than 45 days after identifying the leak, 
except as specified in Sec.  63.1088(d). Repair must include re-
monitoring at the monitoring location where the leak was identified 
according to the method specified in Sec.  63.1086(e)(3) to verify that 
the total strippable hydrocarbon concentration or total hydrocarbon 
mass emissions rate is below the applicable leak action level. Repair 
may also include performing the additional monitoring in paragraph (d) 
of this section to verify that the total strippable hydrocarbon 
concentration is below the applicable leak action level. Actions that 
can be taken to achieve repair include but are not limited to:
    (1) Physical modifications to the leaking heat exchanger, such as 
welding the leak or replacing a tube;
    (2) Blocking the leaking tube within the heat exchanger;
    (3) Changing the pressure so that water flows into the process 
fluid;
    (4) Replacing the heat exchanger or heat exchanger bundle; or
    (5) Isolating, bypassing, or otherwise removing the leaking heat 
exchanger from service until it is otherwise repaired.
    (d) Beginning no later than the compliance dates specified in Sec.  
63.1081(a), if you detect a leak when monitoring a cooling tower return 
line according to Sec.  63.1086(e)(1)(i), you may conduct additional 
monitoring of each heat exchanger or group of heat exchangers 
associated with the heat exchange system for which the leak was 
detected, as provided in Sec.  63.1086(e)(1)(ii). If no leaks are 
detected when monitoring according to the requirements of Sec.  
63.1086(e)(1)(ii), the heat exchange system is considered to have met 
the repair requirements through re-monitoring of the heat exchange 
system, as provided in paragraph (c) of this section.

0
11. Section 63.1088 is amended by revising the introductory text and by 
adding paragraph (d) to read as follows:


Sec.  63.1088   In what situations may I delay leak repair, and what 
actions must I take for delay of repair?

    You may delay the repair of heat exchange systems if the leaking 
equipment is isolated from the process. At any time before the 
compliance dates specified in Sec.  63.1081(a), you may also delay 
repair if repair is technically infeasible without a shutdown, and you 
meet one of the conditions in paragraphs (a) through (c) of this 
section. Beginning no later than the compliance dates specified in 
Sec.  63.1081(a), paragraphs (a) through (c) of this section no longer 
apply; instead, you may delay repair if the conditions in paragraph (d) 
of this section are met.
* * * * *
    (d) Beginning no later than the compliance dates specified in Sec.  
63.1081(a), you may delay repair when one of the conditions in 
paragraph (d)(1) or (2) of this section is met and the leak is less 
than the delay of repair action level specified in paragraph (d)(3) of 
this section. You must determine if a delay of repair is necessary as 
soon as practicable, but no later than 45 days after first identifying 
the leak.
    (1) If the repair is technically infeasible without a shutdown and 
the total strippable hydrocarbon concentration or total hydrocarbon 
mass emissions rate is initially and remains less than the delay of 
repair action level for all monitoring periods during the delay of 
repair, then you may delay repair until the next scheduled shutdown of 
the heat exchange system. If, during subsequent monitoring, the delay 
of repair action level is exceeded, then you must repair the leak 
within 30 days of the monitoring event in which the leak was equal to 
or exceeded the delay of repair action level.
    (2) If the necessary equipment, parts, or personnel are not 
available and the total strippable hydrocarbon concentration or total 
hydrocarbon mass emissions rate is initially and remains less than the 
delay of repair action level for all monitoring periods during the 
delay of repair, then you may delay the repair for a maximum of 120 
calendar days. You must demonstrate that the necessary equipment, 
parts, or personnel were not available. If, during subsequent 
monitoring, the delay of repair action level is exceeded, then you must 
repair the leak within 30 days of the monitoring event in which the 
leak was equal to or exceeded the delay of repair action level.
    (3) The delay of repair action level is a total strippable 
hydrocarbon concentration (as methane) in the stripping gas of 62 ppmv 
or, for heat exchange systems with a recirculation rate of 10,000 
gallons per minute or less, the delay of repair action level is a total 
hydrocarbon mass emissions rate (as methane) or 1.8 kg/hr. The delay of 
repair action level is assessed as described in paragraph (d)(3)(i) or 
(ii) of this section, as applicable.
    (i) For once-through heat exchange systems for which the inlet 
water feed

[[Page 40422]]

is monitored as described in Sec.  63.1086(e)(2)(ii), the delay of 
repair action level is exceeded if the difference in the measurement 
value of the sample taken from a location specified in Sec.  
63.1086(e)(2)(i) and the measurement value of the corresponding sample 
taken from the location specified in Sec.  63.1086(e)(2)(ii) equals or 
exceeds the delay of repair action level.
    (ii) For all other heat exchange systems, the delay of repair 
action level is exceeded if a measurement value of the sample taken 
from a location specified in Sec.  63.1086(e)(1)(i) and (ii) or Sec.  
63.1086(e)(2)(i) equals or exceeds the delay of repair action level.

0
12. Section 63.1089 is amended by revising paragraphs (d) and (e) to 
read as follows:


Sec.  63.1089   What records must I keep?

* * * * *
    (d) At any time before the compliance dates specified in Sec.  
63.1081(a), you must keep documentation of delay of repair as specified 
in Sec.  63.1088(a) through (c). Beginning no later than the compliance 
dates specified in Sec.  63.1081(a), the requirement to keep 
documentation of delay of repair as specified in Sec.  63.1088(a) 
through (c) no longer applies; instead, you must keep documentation of 
delay of repair as specified in paragraphs (d)(1) through (4) of this 
section.
    (1) The reason(s) for delaying repair.
    (2) A schedule for completing the repair as soon as practical.
    (3) The date and concentration or mass emissions rate of the leak 
as first identified and the results of all subsequent monitoring events 
during the delay of repair.
    (4) An estimate of the potential total hydrocarbon emissions from 
the leaking heat exchange system or heat exchanger for each required 
delay of repair monitoring interval following the applicable procedures 
in paragraphs (d)(4)(i) through (iii) of this section.
    (i) If you comply with the total strippable hydrocarbon 
concentration leak action level, as specified in Sec.  63.1086(e)(4), 
you must calculate the mass emissions rate by complying with the 
requirements of Sec.  63.1086(e)(3)(ii) or by determining the mass flow 
rate of the cooling water at the monitoring location where the leak was 
detected. If the monitoring location is an individual cooling tower 
riser, determine the total cooling water mass flow rate to the cooling 
tower. Cooling water mass flow rates may be determined using direct 
measurement, pump curves, heat balance calculations, or other 
engineering methods. If you determine the mass flow rate of the cooling 
water, calculate the mass emissions rate by converting the stripping 
gas leak concentration (in ppmv as methane) to an equivalent liquid 
concentration, in parts per million by weight (ppmw), using equation 7-
1 from ``Air Stripping Method (Modified El Paso Method) for 
Determination of Volatile Organic Compound Emissions from Water 
Sources'' (incorporated by reference--see Sec.  63.14) and multiply the 
equivalent liquid concentration by the mass flow rate of the cooling 
water.
    (ii) For delay of repair monitoring intervals prior to repair of 
the leak, calculate the potential total hydrocarbon emissions for the 
leaking heat exchange system or heat exchanger for the monitoring 
interval by multiplying the mass emissions rate, determined in Sec.  
63.1086(e)(3)(ii) or paragraph (d)(4)(i) of this section, by the 
duration of the delay of repair monitoring interval. The duration of 
the delay of repair monitoring interval is the time period starting at 
midnight on the day of the previous monitoring event or at midnight on 
the day the repair would have been completed if the repair had not been 
delayed, whichever is later, and ending at midnight of the day the of 
the current monitoring event.
    (iii) For delay of repair monitoring intervals ending with a 
repaired leak, calculate the potential total hydrocarbon emissions for 
the leaking heat exchange system or heat exchanger for the final delay 
of repair monitoring interval by multiplying the duration of the final 
delay of repair monitoring interval by the mass emissions rate 
determined for the last monitoring event prior to the re-monitoring 
event used to verify the leak was repaired. The duration of the final 
delay of repair monitoring interval is the time period starting at 
midnight of the day of the last monitoring event prior to re-monitoring 
to verify the leak was repaired and ending at the time of the re-
monitoring event that verified that the leak was repaired.
    (e) At any time before the compliance dates specified in Sec.  
63.1081(a), if you validate a 40 CFR part 136 method for the HAP listed 
in Table 1 to this subpart according to the procedures in appendix D to 
this part, then you must keep a record of the test data and 
calculations used in the validation. On the compliance dates specified 
in Sec.  63.1081(a), this requirement no longer applies.

0
13. Section 63.1090 is amended by revising the introductory text and by 
adding paragraph (f) to read as follows:


Sec.  63.1090   What reports must I submit?

    If you delay repair for your heat exchange system, you must report 
the delay of repair in the semiannual report required by Sec.  
63.1110(e). If the leak remains unrepaired, you must continue to report 
the delay of repair in semiannual reports until you repair the leak. 
Except as provided in paragraph (f) of this section, you must include 
the information in paragraphs (a) through (e) of this section in the 
semiannual report.
* * * * *
    (f) For heat exchange systems subject to Sec.  63.1085(e) and (f), 
Periodic Reports must include the information specified in paragraphs 
(f)(1) through (5) of this section, in lieu of the information 
specified in paragraphs (a) through (e) of this section.
    (1) The number of heat exchange systems at the plant site subject 
to the monitoring requirements in Sec.  63.1085(e) and (f) during the 
reporting period.
    (2) The number of heat exchange systems subject to the monitoring 
requirements in Sec.  63.1085(e) and (f) at the plant site found to be 
leaking during the reporting period.
    (3) For each monitoring location where the total strippable 
hydrocarbon concentration or total hydrocarbon mass emissions rate was 
determined to be equal to or greater than the applicable leak 
definitions specified in Sec.  63.1086(e)(5) during the reporting 
period, identification of the monitoring location (e.g., unique 
monitoring location or heat exchange system ID number), the measured 
total strippable hydrocarbon concentration or total hydrocarbon mass 
emissions rate, the date the leak was first identified, and, if 
applicable, the date the source of the leak was identified;
    (4) For leaks that were repaired during the reporting period 
(including delayed repairs), identification of the monitoring location 
associated with the repaired leak, the total strippable hydrocarbon 
concentration or total hydrocarbon mass emissions rate measured during 
re-monitoring to verify repair, and the re-monitoring date (i.e., the 
effective date of repair); and
    (5) For each delayed repair, identification of the monitoring 
location associated with the leak for which repair is delayed, the date 
when the delay of repair began, the date the repair is expected to be 
completed (if the leak is not repaired during the reporting period), 
the total strippable hydrocarbon concentration or total hydrocarbon 
mass emissions rate and date of each monitoring event conducted on the 
delayed repair during the reporting period, and an estimate of the 
potential total hydrocarbon emissions over the reporting period 
associated with the delayed repair.

[[Page 40423]]


0
14. Section 63.1095 is amended by:
0
a. Revising paragraph (a)(1) introductory text;
0
b. Adding paragraph (a)(1)(vi);
0
c. Revising paragraphs (a)(3), (b) introductory text, and (b)(1); and
0
d. Adding paragraph (b)(3).
    The revisions and additions read as follows:


Sec.  63.1095   What specific requirements must I comply with?

* * * * *
    (a) * * *
    (1) Route the continuous butadiene stream to a treatment process or 
wastewater treatment system used to treat benzene waste streams that 
complies with the standards specified in 40 CFR 61.348. Comply with the 
requirements of 40 CFR part 61, subpart FF; with the changes in Table 2 
to this subpart, and as specified in paragraphs (a)(1)(i) through (vi) 
of this section.
* * * * *
    (vi) Beginning no later than the compliance dates specified in 
Sec.  63.1081(b), if you use a steam-assisted, air-assisted, non-
assisted, or pressure-assisted multi-point flare to comply with 40 CFR 
part 61, subpart FF, then you must comply with the requirements Sec.  
63.1103(e)(4) in lieu of 40 CFR 61.349(a)(2)(iii) and (d), 40 CFR 
61.354(c)(3), 40 CFR 61.356(f)(2)(i)(D) and (j)(7), and 40 CFR 
61.357(d)(7)(iv)(F).
* * * * *
    (3) Before July 6, 2023, if the total annual benzene quantity from 
waste at your facility is less than 10 Mg/yr, as determined according 
to 40 CFR 61.342(a), comply with the requirements of this section at 
all times except during periods of startup, shutdown, and malfunction, 
if the startup, shutdown, or malfunction precludes the ability of the 
affected source to comply with the requirements of this section and the 
owner or operator follows the provisions for periods of startup, 
shutdown, and malfunction, as specified in Sec.  63.1111. Beginning on 
July 6, 2023, if the total annual benzene quantity from waste at your 
facility is less than 10 Mg/yr, as determined according to 40 CFR 
61.342(a), you must comply with the requirements of this section at all 
times.
    (b) Waste streams that contain benzene. For waste streams that 
contain benzene, you must comply with the requirements of 40 CFR part 
61, subpart FF, except as specified in Table 2 to this subpart and 
paragraph (b)(3) of this section. You must manage and treat waste 
streams that contain benzene as specified in either paragraph (b)(1) or 
(2) of this section.
    (1) If the total annual benzene quantity from waste at your 
facility is less than 10 Mg/yr, as determined according to 40 CFR 
61.342(a), manage and treat spent caustic waste streams and dilution 
steam blowdown waste streams according to 40 CFR 61.342(c)(1) through 
(c)(3)(i). Before July 6, 2023, the requirements of this paragraph 
(b)(1) shall apply at all times except during periods of startup, 
shutdown, and malfunction, if the startup, shutdown, or malfunction 
precludes the ability of the affected source to comply with the 
requirements of this section and the owner or operator follows the 
provisions for periods of startup, shutdown, and malfunction, as 
specified in Sec.  63.1111. Beginning on July 6, 2023, the requirements 
of this paragraph (b)(1) shall apply at all times.
* * * * *
    (3) Beginning no later than the compliance dates specified in Sec.  
63.1081(b), if you use a steam-assisted, air-assisted, non-assisted, or 
pressure-assisted multi-point flare to comply with 40 CFR part 61, 
subpart FF, then you must comply with the requirements of Sec.  
63.1103(e)(4) in lieu of 40 CFR 61.349(a)(2)(iii) and (d), 40 CFR 
61.354(c)(3), 40 CFR 61.356(f)(2)(i)(D) and (j)(7), and 40 CFR 
61.357(d)(7)(iv)(F).

0
15. Table 2 to subpart XX of part 63 is amended by revising the first 
three entries to row 1 and the first two entries to row 2 to read as 
follows:

    Table 2 to Subpart XX of Part 63--Requirements of 40 CFR Part 61,
    Subpart FF, Not Included in the Requirements for This Subpart and
                         Alternate Requirements
------------------------------------------------------------------------
 If the total annual benzene
quantity for waste from your   Do not comply with:     Instead, comply
      facility is * * *                                     with:
------------------------------------------------------------------------
1. Less than 10 Mg/yr.......  40 CFR 61.340.......  Sec.   63.1093.
                              40 CFR                There is no
                               61.342(c)(3)(ii),     equivalent
                               (d), and (e).         requirement.
                              40 CFR 61.342(f)....  Sec.   63.1096.
 
                              * * * * * * *
2. Greater than or equal to   40 CFR 61.340.......  Sec.   63.1093.
 10 Mg/yr.
                              40 CFR 61.342(f)....  Sec.   63.1096.
 
                              * * * * * * *
------------------------------------------------------------------------

Subpart YY--National Emission Standards for Hazardous Air 
Pollutants for Source Categories: Generic Maximum Achievable 
Control Technology Standards

0
16. Section 63.1100 is amended by:
0
a. Revising the heading to Table 1 to Sec.  63.1100(a);
0
b. Revising the entries for ``Carbon Black Production,'' ``Cyanide 
Chemicals Manufacturing,'' ``Ethylene Production,'' and ``Spandex 
Production'';
0
c. Revising footnote c to Table 1 to Sec.  63.1100(a);
0
d. Revising paragraphs (b), (g) introductory text, and (g)(4)(ii);
0
e. Adding paragraph (g)(4)(iii);
0
f. Revising paragraph (g)(5); and
0
g. Adding paragraph (g)(7).
    The revisions and additions read as follows:


Sec.  63.1100   Applicability.

    (a) * * *

[[Page 40424]]



                                                               Table 1 to Sec.   63.1100(a)--Source Category MACT a Applicability
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                                               Source category
         Source category              Storage vessels        Process vents        Transfer racks         Equipment leaks         Wastewater streams            Other          MACT requirements
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                                          * * * * * * *
Carbon Black Production..........  No..................  Yes.................  No..................  No.....................  No.....................  No..................  Sec.   63.1103(f).
Cyanide Chemicals Manufacturing..  Yes.................  Yes.................  Yes.................  Yes....................  Yes....................  No..................  Sec.   63.1103(g).
Ethylene Production..............  Yes.................  Yes.................  Yes.................  Yes....................  Yes....................  Yes \c\.............  Sec.   63.1103(e).
 
                                                                                          * * * * * * *
Spandex Production...............  Yes.................  Yes.................  No..................  No.....................  No.....................  Yes \d\.............  Sec.   63.1103(h).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Maximum achievable control technology.
\b\ Fiber spinning lines using spinning solution or suspension containing acrylonitrile.
\c\ Heat exchange systems as defined in Sec.   63.1082(b).
\d\ Fiber spinning lines.

    (b) Subpart A requirements. The following provisions of subpart A 
of this part (General Provisions), Sec. Sec.  63.1 through 63.5, and 
Sec. Sec.  63.12 through 63.15, apply to owners or operators of 
affected sources subject to this subpart. Beginning no later than the 
compliance dates specified in Sec.  63.1102(c), for ethylene production 
affected sources, Sec. Sec.  63.7(a)(4), (c), (e)(4), and (g)(2), and 
63.10(b)(2)(vi) also apply.
* * * * *
    (g) Overlap with other regulations. Paragraphs (g)(1) through (7) 
of this section specify the applicability of this subpart YY emission 
point requirements when other rules may apply. Where this subpart YY 
allows an owner or operator an option to comply with one or another 
regulation to comply with this subpart YY, an owner or operator must 
report which regulation they choose to comply with in the Notification 
of Compliance Status report required by Sec.  63.1110(a)(4).
    (4) * * *
    (ii) After the compliance dates specified in Sec.  63.1102, 
equipment that must be controlled according to this subpart YY and 
subpart H of this part is in compliance with the equipment leak 
requirements of this subpart YY if it complies with either set of 
requirements. For ethylene production affected sources, the requirement 
in Sec.  63.1103(e)(9)(i) also applies. The owner or operator must 
specify the rule with which they will comply in the Notification of 
Compliance Status report required by Sec.  63.1110(a)(4).
    (iii) Beginning no later than the compliance dates specified in 
Sec.  63.1102(c), for ethylene production affected sources, equipment 
that must be controlled according to this subpart YY and subpart VVa of 
40 CFR part 60 is required only to comply with the equipment leak 
requirements of this subpart, except the owner or operator must also 
comply with the calibration drift assessment requirements specified at 
40 CFR 60.485a(b)(2) if they are required to do so in subpart VVa of 40 
CFR part 60. When complying with the calibration drift assessment 
requirements at 40 CFR 60.485a(b)(2), the requirement at 40 CFR 
60.486a(e)(8)(v) to record the instrument reading for each scale used 
applies.
    (5) Overlap of this subpart YY with other regulations for 
wastewater for source categories other than ethylene production. (i) 
After the compliance dates specified in Sec.  63.1102 for an affected 
source subject to this subpart, a wastewater stream that is subject to 
the wastewater requirements of this subpart and the wastewater 
requirements of subparts F, G, and H of this part (collectively known 
as the ``HON'') shall be deemed to be in compliance with the 
requirements of this subpart if it complies with either set of 
requirements. In any instance where a source subject to this subpart is 
collocated with a Synthetic Organic Chemical Manufacturing Industry 
(SOCMI) source, and a single wastewater treatment facility treats both 
Group 1 wastewaters and wastewater residuals from the source subject to 
this subpart and wastewaters from the SOCMI source, a certification by 
the treatment facility that they will manage and treat the waste in 
conformity with the specific control requirements set forth in 
Sec. Sec.  63.133 through 63.147 will also be deemed sufficient to 
satisfy the certification requirements for wastewater treatment under 
this subpart.
* * * * *
    (7) Overlap of this subpart YY with other regulations for flares 
for the ethylene production source category. (i) Beginning no later 
than the compliance dates specified in Sec.  63.1102(c), flares that 
are subject to 40 CFR 60.18 or Sec.  63.11 and used as a control device 
for an emission point subject to the requirements in Table 7 to Sec.  
63.1103(e) are required to comply only with Sec.  63.1103(e)(4). At any 
time before the compliance dates specified in Sec.  63.1102(c), flares 
that are subject to 40 CFR 60.18 or Sec.  63.11 and elect to comply 
with Sec.  63.1103(e)(4) are required to comply only with Sec.  
63.1103(e)(4).
    (ii) Beginning no later than the compliance dates specified in 
Sec.  63.1102(c), flares subject to Sec.  63.987 and used as a control 
device for an emission point subject to the requirements in Table 7 to 
Sec.  63.1103(e) are only required to comply with Sec.  63.1103(e)(4).
    (iii) Beginning no later than the compliance dates specified in 
Sec.  63.1102(c), flares subject to the requirements in 40 CFR part 63, 
subpart CC and used as a control device for an emission point subject 
to the requirements in Table 7 to Sec.  63.1103(e) are only required to 
comply with the flare requirements in 40 CFR part 63, subpart CC. This 
paragraph does not apply to multi-point pressure assisted flares.

0
17. Section 63.1101 is amended by revising the definitions of 
``Pressure relief device or valve'' and ``Shutdown'' to read as 
follows:


Sec.  63.1101   Definitions.

* * * * *
    Pressure relief device or valve means a safety device used to 
prevent operating pressures from exceeding the maximum allowable 
working pressure of the process equipment. A common pressure relief 
device is a spring-loaded pressure relief valve. Devices that are 
actuated either by a pressure of less than or equal to 2.5 pounds per 
square inch gauge or by a vacuum are not pressure relief devices. This 
definition does not apply to ethylene production affected sources.
* * * * *

[[Page 40425]]

    Shutdown means the cessation of operation of an affected source or 
equipment that is used to comply with this subpart, or the emptying and 
degassing of a storage vessel. For the purposes of this subpart, 
shutdown includes, but is not limited to, periodic maintenance, 
replacement of equipment, or repair. Shutdown does not include the 
routine rinsing or washing of equipment in batch operation between 
batches. Shutdown includes the decoking of ethylene cracking furnaces.
* * * * *

0
18. Section 63.1102 is amended by revising paragraph (a) introductory 
text and adding paragraph (c) to read as follows:


Sec.  63.1102   Compliance schedule.

    (a) General requirements. Affected sources, as defined in Sec.  
63.1103(a)(1)(i) for acetyl resins production, Sec.  63.1103(b)(1)(i) 
for acrylic and modacrylic fiber production, Sec.  63.1103(c)(1)(i) for 
hydrogen fluoride production, Sec.  63.1103(d)(1)(i) for polycarbonate 
production, Sec.  63.1103(e)(1)(i) for ethylene production, Sec.  
63.1103(f)(1)(i) for carbon black production, Sec.  63.1103(g)(1)(i) 
for cyanide chemicals manufacturing, or Sec.  63.1103(h)(1)(i) for 
spandex production shall comply with the appropriate provisions of this 
subpart and the subparts referenced by this subpart YY according to the 
schedule in paragraph (a)(1) or (2) of this section, as appropriate, 
except as provided in paragraph (b) of this section. Affected sources 
in ethylene production also must comply according to paragraph (c) of 
this section. Proposal and effective dates are specified in Table 1 to 
this section.
* * * * *
    (c) All ethylene production affected sources that commenced 
construction or reconstruction on or before October 9, 2019, must be in 
compliance with the requirements listed in paragraphs (c)(1) through 
(13) of this section upon initial startup or July 6, 2023, whichever is 
later. All ethylene production affected sources that commenced 
construction or reconstruction after October 9, 2019, must be in 
compliance with the requirements listed in paragraphs (c)(1) through 
(13) of this section upon initial startup, or July 6, 2020, whichever 
is later.
    (1) Overlap requirements specified in Sec.  63.1100(g)(4)(iii) and 
(7), if applicable.
    (2) The storage vessel requirements specified in paragraphs 
(b)(1)(iii) and (c)(1)(ii) of Table 7 to Sec.  63.1103(e), and the 
degassing requirements specified in Sec.  63.1103(e)(10).
    (3) The ethylene process vent requirements specified in paragraph 
(d)(1)(ii) of Table 7 to Sec.  63.1103(e).
    (4) The transfer rack requirements specified in Sec.  
63.1105(a)(5).
    (5) The equipment requirements specified in paragraph (f)(1)(ii) of 
Table 7 to Sec.  63.1103(e) and Sec.  63.1107(h).
    (6) The bypass line requirements specified in paragraph (i) of 
Table 7 to Sec.  63.1103(e), and Sec.  63.1103(e)(6).
    (7) The decoking requirements for ethylene cracking furnaces 
specified in paragraph (j) of Table 7 to Sec.  63.1103(e), and Sec.  
63.1103(e)(7) and (8).
    (8) The flare requirements specified in Sec.  63.1103(e)(4).
    (9) The maintenance vent requirements specified in Sec.  
63.1103(e)(5).
    (10) The requirements specified in Sec.  63.1103(e)(9).
    (11) The requirements in Sec.  63.1108(a)(4)(i), (b)(1)(ii), 
(b)(2), and (b)(4)(ii)(B).
    (12) The recordkeeping requirements specified in Sec.  63.1109(e) 
through (i).
    (13) The reporting requirements specified in Sec.  63.1110(a)(10), 
(d)(1)(iv) and (v), and (e)(4) through (8).
* * * * *

0
19. Section 63.1103 is amended:
0
a. By revising the definition of ``In organic hazardous air pollutant 
or in organic HAP service'' in paragraph (b)(2);
0
b. By revising paragraphs (e)(1)(i) introductory text, (e)(1)(i)(F), 
and (e)(1)(ii)(J);
0
c. In paragraph (e)(2) by;
0
i. Adding in alphabetical order a definition for ``Decoking 
operation'';
0
ii. Revising the definition of ``Ethylene process vent'';
0
iii. Adding in alphabetical order a definition for ``Force majeure 
event'';
0
iv. Removing the definition of ``Heat exchange system'';
0
v. Adding in alphabetical order definitions for ``Periodically 
discharged,'' ``Pressure-assisted multi-point flare,'' ``Pressure 
relief device,'' ``Radiant tube(s),'' and ``Relief valve'';
0
d. By revising paragraph (e)(3);
0
e. By adding paragraphs (e)(4) through (10); and
0
e. By revising Table 7 to Sec.  63.1103(e).
    The revisions and additions read as follows:


Sec.  63.1103   Source category-specific applicability, definitions, 
and requirements.

* * * * *
    (b) * * *
    (2) * * *
    In organic hazardous air pollutant or in organic HAP service means, 
for acrylic and modacrylic fiber production affected sources, that a 
piece of equipment either contains or contacts a fluid (liquid or gas) 
that is at least 10 percent by weight of total organic HAP as 
determined according to the provisions of Sec.  63.180(d). The 
provisions of Sec.  63.180(d) also specify how to determine that a 
piece of equipment is not in organic HAP service.
* * * * *
    (e) * * *
    (1) * * *
    (i) Affected source. For the ethylene production (as defined in 
paragraph (e)(2) of this section) source category, the affected source 
comprises all emission points listed in paragraphs (e)(1)(i)(A) through 
(G) of this section that are associated with an ethylene production 
unit that is located at a major source, as defined in section 112(a) of 
the Act.
* * * * *
    (F) All heat exchange systems (as defined in Sec.  63.1082(b)) 
associated with an ethylene production unit.
* * * * *
    (ii) * * *
    (J) Air emissions from all ethylene cracking furnaces.
* * * * *
    (2) * * *
    Decoking operation means the coke combustion activity that occurs 
inside the radiant tube(s) in the ethylene cracking furnace firebox. 
Coke combustion activities during decoking can also occur in other 
downstream equipment such as the process gas outlet piping and transfer 
line exchangers or quench points.
    Ethylene process vent means a gas stream with a flow rate greater 
than 0.005 standard cubic meters per minute containing greater than 20 
parts per million by volume HAP that is continuously discharged during 
operation of an ethylene production unit. On and after July 6, 2023, 
ethylene process vent means a gas stream with a flow rate greater than 
0.005 standard cubic meters per minute containing greater than 20 parts 
per million by volume HAP that is continuously or periodically 
discharged during operation of an ethylene production unit. Ethylene 
process vents are gas streams that are discharged to the atmosphere (or 
the point of entry into a control device, if any) either directly or 
after passing through one or more recovery devices. Ethylene process 
vents do not include:
    (A) Pressure relief device discharges;
    (B) Gaseous streams routed to a fuel gas system, including any 
flares using fuel gas, of which less than 50 percent

[[Page 40426]]

of the fuel gas is derived from an ethylene production unit;
    (C) Gaseous streams routed to a fuel gas system whereby any flares 
using fuel gas, of which 50 percent or more of the fuel gas is derived 
from an ethylene production unit, comply with Sec.  63.1103(e)(4) 
beginning no later than the compliance dates specified in Sec.  
63.1102(c);
    (D) Leaks from equipment regulated under this subpart;
    (E) Episodic or nonroutine releases such as those associated with 
startup, shutdown, and malfunction until July 6, 2023;
    (F) In situ sampling systems (online analyzers) until July 6, 2023; 
and
    (G) Coke combustion emissions from decoking operations beginning no 
later than the compliance dates specified in Sec.  63.1102(c).
* * * * *
    Force majeure event means a release of HAP, either directly to the 
atmosphere from a pressure relief device or discharged via a flare, 
that is demonstrated to the satisfaction of the Administrator to result 
from an event beyond the owner or operator's control, such as natural 
disasters; acts of war or terrorism; loss of a utility external to the 
ethylene production unit (e.g., external power curtailment), excluding 
power curtailment due to an interruptible service agreement; and fire 
or explosion originating at a near or adjoining facility outside of the 
ethylene production unit that impacts the ethylene production unit's 
ability to operate.
* * * * *
    Periodically discharged means gas stream discharges that are 
intermittent for which the total organic HAP concentration is greater 
than 20 parts per million by volume and total volatile organic compound 
emissions are 50 pounds per day or more. These intermittent discharges 
are associated with routine operations, maintenance activities, 
startups, shutdowns, malfunctions, or process upsets and do not include 
pressure relief device discharges or discharges classified as 
maintenance vents.
    Pressure-assisted multi-point flare means a flare system consisting 
of multiple flare burners in staged arrays whereby the vent stream 
pressure is used to promote mixing and smokeless operation at the flare 
burner tips. Pressure-assisted multi-point flares are designed for 
smokeless operation at velocities up to Mach = 1 conditions (i.e., 
sonic conditions), can be elevated or at ground level, and typically 
use cross-lighting for flame propagation to combust any flare vent 
gases sent to a particular stage of flare burners.
    Pressure relief device means a valve, rupture disk, or similar 
device used only to release an unplanned, nonroutine discharge of gas 
from process equipment in order to avoid safety hazards or equipment 
damage. A pressure relief device discharge can result from an operator 
error, a malfunction such as a power failure or equipment failure, or 
other unexpected cause. Such devices include conventional, spring-
actuated relief valves, balanced bellows relief valves, pilot-operated 
relief valves, rupture disks, and breaking, buckling, or shearing pin 
devices. Devices that are actuated either by a pressure of less than or 
equal to 2.5 pounds per square inch gauge or by a vacuum are not 
pressure relief devices.
    Radiant tube(s) means any portion of the tube coil assembly located 
within the ethylene cracking furnace firebox whereby a thermal cracking 
reaction of hydrocarbons (in the presence of steam) occurs. 
Hydrocarbons and steam pass through the radiant tube(s) of the ethylene 
cracking furnace during normal operation and coke is removed from the 
inside of the radiant tube(s) during decoking operation.
    Relief valve means a type of pressure relief device that is 
designed to re-close after the pressure relief.
* * * * *
    (3) Requirements. The owner or operator must control organic HAP 
emissions from each affected source emission point by meeting the 
applicable requirements specified in Table 7 to this section. An owner 
or operator must perform the applicability assessment procedures and 
methods for process vents specified in Sec.  63.1104, except for 
paragraphs (d), (g), (h) through (j), (l)(1), and (n). An owner or 
operator must perform the applicability assessment procedures and 
methods for equipment leaks specified in Sec.  63.1107. General 
compliance, recordkeeping, and reporting requirements are specified in 
Sec.  Sec.  63.1108 through 63.1112. Before July 6, 2023, minimization 
of emissions from startup, shutdown, and malfunctions must be addressed 
in the startup, shutdown, and malfunction plan required by Sec.  
63.1111; the plan must also establish reporting and recordkeeping of 
such events. A startup, shutdown, and malfunction plan is not required 
on and after July 6, 2023 and the requirements specified in Sec.  
63.1111 no longer apply; however, for historical compliance purposes, a 
copy of the plan must be retained and available on-site for five years 
after July 6, 2023. Except as specified in paragraph (e)(4)(i) of this 
section, procedures for approval of alternate means of emission 
limitations are specified in Sec.  63.1113.
    (4) Flares. Beginning no later than the compliance dates specified 
in Sec.  63.1102(c), if a steam-assisted, air-assisted, non-assisted, 
or pressure-assisted multi-point flare is used as a control device for 
an emission point subject to the requirements in Table 7 to this 
section, then the owner or operator must meet the applicable 
requirements for flares as specified in Sec. Sec.  63.670 and 63.671 of 
subpart CC, including the provisions in Tables 12 and 13 to subpart CC 
of this part, except as specified in paragraphs (e)(4)(i) through (xiv) 
of this section. This requirement also applies to any flare using fuel 
gas from a fuel gas system, of which 50 percent or more of the fuel gas 
is derived from an ethylene production unit, being used to control an 
emission point subject to the requirements in Table 7 of this section. 
For purposes of compliance with this paragraph, the following terms are 
defined in Sec.  63.641 of subpart CC: Assist air, assist steam, center 
steam, combustion zone, combustion zone gas, flare, flare purge gas, 
flare supplemental gas, flare sweep gas, flare vent gas, lower steam, 
net heating value, perimeter assist air, pilot gas, premix assist air, 
total steam, and upper steam.
    (i) The owner or operator may elect to comply with the alternative 
means of emissions limitation requirements specified in of Sec.  
63.670(r) of subpart CC in lieu of the requirements in Sec.  63.670(d) 
through (f) of subpart CC, as applicable. However, instead of complying 
with Sec.  63.670(r)(3) of subpart CC, the owner or operator must 
submit the alternative means of emissions limitation request following 
the requirements in Sec.  63.1113.
    (ii) Instead of complying with Sec.  63.670(o)(2)(i) of subpart CC, 
the owner or operator must develop and implement the flare management 
plan no later than the compliance dates specified in Sec.  63.1102(c).
    (iii) Instead of complying with Sec.  63.670(o)(2)(iii) of subpart 
CC, if required to develop a flare management plan and submit it to the 
Administrator, then the owner or operator must also submit all versions 
of the plan in portable document format (PDF) to the EPA via the 
Compliance and Emissions Data Reporting Interface (CEDRI), which can be 
accessed through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). If you claim some of the information in your flare 
management plan is confidential business information (CBI), submit a 
version with the CBI omitted via CEDRI. A complete plan, including 
information claimed to

[[Page 40427]]

be CBI and clearly marked as CBI, must be mailed to the following 
address: U.S. Environmental Protection Agency, Office of Air Quality 
Planning and Standards, Sector Policies and Programs Division, U.S. EPA 
Mailroom (E143-01), Attention: Ethylene Production Sector Lead, 109 
T.W. Alexander Drive, Research Triangle Park, NC 27711.
    (iv) Section 63.670(o)(3)(ii) of subpart CC and all references to 
Sec.  63.670(o)(3)(ii) of subpart CC do not apply. Instead, the owner 
or operator must comply with the maximum flare tip velocity operating 
limit at all times.
    (v) Substitute ``ethylene production unit'' for each occurrence of 
``petroleum refinery.''
    (vi) Each occurrence of ``refinery'' does not apply.
    (vii) Except as specified in paragraph (e)(4)(vii)(G) of this 
section, if a pressure-assisted multi-point flare is used as a control 
device for an emission point subject to the requirements in Table 7 to 
this section, then the owner or operator must comply with the 
requirements specified in paragraphs (e)(4)(vii)(A) through (F) of this 
section.
    (A) The owner or operator is not required to comply with the flare 
tip velocity requirements in Sec.  63.670(d) and (k) of subpart CC;
    (B) The owner or operator must substitute ``800'' for each 
occurrence of ``270'' in Sec.  63.670(e) of subpart CC;
    (C) The owner or operator must determine the 15-minute block 
average NHVvg using only the direct calculation method specified in 
Sec.  63.670(l)(5)(ii) of subpart CC;
    (D) Instead of complying with Sec.  63.670(b) and (g) of subpart 
CC, if a pressure-assisted multi-point flare uses cross-lighting on a 
stage of burners rather than having an individual pilot flame on each 
burner, the owner or operator must operate each stage of the pressure-
assisted multi-point flare with a flame present at all times when 
regulated material is routed to that stage of burners. Each stage of 
burners that cross-lights in the pressure-assisted multi-point flare 
must have at least two pilots with at least one continuously lit and 
capable of igniting all regulated material that is routed to that stage 
of burners. Each 15-minute block during which there is at least one 
minute where no pilot flame is present on a stage of burners when 
regulated material is routed to that stage is a deviation of the 
standard. Deviations in different 15-minute blocks from the same event 
are considered separate deviations. The pilot flame(s) on each stage of 
burners that use cross-lighting must be continuously monitored by a 
thermocouple or any other equivalent device used to detect the presence 
of a flame;
    (E) Unless the owner or operator of a pressure-assisted multi-point 
flare chooses to conduct a cross-light performance demonstration as 
specified in this paragraph, the owner or operator must ensure that if 
a stage of burners on the flare uses cross-lighting, that the distance 
between any two burners in series on that stage is no more than 6 feet 
when measured from the center of one burner to the next burner. A 
distance greater than 6 feet between any two burners in series may be 
used provided the owner or operator conducts a performance 
demonstration that confirms the pressure-assisted multi-point flare 
will cross-light a minimum of three burners and the spacing between the 
burners and location of the pilot flame must be representative of the 
projected installation. The compliance demonstration must be approved 
by the permitting authority and a copy of this approval must be 
maintained onsite. The compliance demonstration report must include: A 
protocol describing the test methodology used, associated test method 
QA/QC parameters, the waste gas composition and NHVcz of the gas 
tested, the velocity of the waste gas tested, the pressure-assisted 
multi-point flare burner tip pressure, the time, length, and duration 
of the test, records of whether a successful cross-light was observed 
over all of the burners and the length of time it took for the burners 
to cross-light, records of maintaining a stable flame after a 
successful cross-light and the duration for which this was observed, 
records of any smoking events during the cross-light, waste gas 
temperature, meteorological conditions (e.g., ambient temperature, 
barometric pressure, wind speed and direction, and relative humidity), 
and whether there were any observed flare flameouts; and
    (F) The owner or operator of a pressure-assisted multi-point flare 
must install and operate pressure monitor(s) on the main flare header, 
as well as a valve position indicator monitoring system for each 
staging valve to ensure that the flare operates within the proper range 
of conditions as specified by the manufacturer. The pressure monitor 
must meet the requirements in Table 13 to subpart CC of this part.
    (G) If a pressure-assisted multi-point flare is operating under the 
requirements of an approved alternative means of emission limitations, 
the owner or operator shall either continue to comply with the terms of 
the alternative means of emission limitations or comply with the 
provisions in paragraphs (e)(4)(vii)(A) through (F) of this section.
    (viii) If an owner or operator chooses to determine compositional 
analysis for net heating value with a continuous process mass 
spectrometer, the owner or operator must comply with the requirements 
specified in paragraphs (e)(4)(viii)(A) through (G) of this section.
    (A) The owner or operator must meet the requirements in Sec.  
63.671(e)(2). The owner or operator may augment the minimum list of 
calibration gas components found in Sec.  63.671(e)(2) with compounds 
found during a pre-survey or known to be in the gas through process 
knowledge.
    (B) Calibration gas cylinders must be certified to an accuracy of 2 
percent and traceable to National Institute of Standards and Technology 
(NIST) standards.
    (C) For unknown gas components that have similar analytical mass 
fragments to calibration compounds, the owner or operator may report 
the unknowns as an increase in the overlapped calibration gas compound. 
For unknown compounds that produce mass fragments that do not overlap 
calibration compounds, the owner or operator may use the response 
factor for the nearest molecular weight hydrocarbon in the calibration 
mix to quantify the unknown component's NHVvg.
    (D) The owner or operator may use the response factor for n-pentane 
to quantify any unknown components detected with a higher molecular 
weight than n-pentane.
    (E) The owner or operator must perform an initial calibration to 
identify mass fragment overlap and response factors for the target 
compounds.
    (F) The owner or operator must meet applicable requirements in 
Performance Specification 9 of 40 CFR part 60, appendix B, for 
continuous monitoring system acceptance including, but not limited to, 
performing an initial multi-point calibration check at three 
concentrations following the procedure in Section 10.1 and performing 
the periodic calibration requirements listed for gas chromatographs in 
Table 13 to subpart CC of this part, for the process mass spectrometer. 
The owner or operator may use the alternative sampling line temperature 
allowed under Net Heating Value by Gas Chromatograph in Table 13 to 
subpart CC of this part.
    (G) The average instrument calibration error (CE) for each 
calibration compound at any calibration concentration must not differ 
by more than 10 percent from the certified cylinder gas value. The CE 
for each

[[Page 40428]]

component in the calibration blend must be calculated using the 
following equation:
[GRAPHIC] [TIFF OMITTED] TR06JY20.000


Where:

Cm = Average instrument response (ppm)
Ca = Certified cylinder gas value (ppm)

    (ix) An owner or operator using a gas chromatograph or mass 
spectrometer for compositional analysis for net heating value may 
choose to use the CE of NHVmeasured versus the cylinder tag 
value NHV as the measure of agreement for daily calibration and 
quarterly audits in lieu of determining the compound-specific CE. The 
CE for NHV at any calibration level must not differ by more than 10 
percent from the certified cylinder gas value. The CE for must be 
calculated using the following equation:
[GRAPHIC] [TIFF OMITTED] TR06JY20.001


Where:

NHVmeasured = Average instrument response (Btu/scf)
NHVa = Certified cylinder gas value (Btu/scf)

    (x) Instead of complying with Sec.  63.670(p) of subpart CC, the 
owner or operator must keep the flare monitoring records specified in 
Sec.  63.1109(e).
    (xi) Instead of complying with Sec.  63.670(q) of subpart CC, the 
owner or operator must comply with the reporting requirements specified 
in Sec.  63.1110(d) and (e)(4).
    (xii) When determining compliance with the pilot flame requirements 
specified in Sec.  63.670(b) and (g), substitute ``pilot flame or flare 
flame'' for each occurrence of ``pilot flame.''
    (xiii) When determining compliance with the flare tip velocity and 
combustion zone operating limits specified in Sec.  63.670(d) and (e), 
the requirement effectively applies starting with the 15-minute block 
that includes a full 15 minutes of the flaring event. The owner or 
operator is required to demonstrate compliance with the velocity and 
NHVcz requirements starting with the block that contains the fifteenth 
minute of a flaring event. The owner or operator is not required to 
demonstrate compliance for the previous 15-minute block in which the 
event started and contained only a fraction of flow.
    (xiv) In lieu of meeting the requirements in Sec. Sec.  63.670 and 
63.671 of subpart CC, an owner or operator may submit a request to the 
Administrator for approval of an alternative test method in accordance 
with Sec.  63.7(f). The alternative test method must be able to 
demonstrate on an ongoing basis at least once every 15-minutes that the 
flare meets 96.5% combustion efficiency and provide a description of 
the alternative recordkeeping and reporting that would be associated 
with the alternative test method. The alternative test method request 
may also include a request to use the alternative test method in lieu 
of the pilot or flare flame monitoring requirements of 63.670(g).
    (5) Maintenance vents. Unless an extension is requested in 
accordance with the provisions in Sec.  63.6(i) of subpart A, beginning 
no later than the compliance dates specified in Sec.  63.1102(c), an 
owner or operator may designate an ethylene process vent as a 
maintenance vent if the vent is only used as a result of startup, 
shutdown, maintenance, or inspection of equipment where equipment is 
emptied, depressurized, degassed, or placed into service. The owner or 
operator must comply with the applicable requirements in paragraphs 
(e)(5)(i) through (iii) of this section for each maintenance vent.
    (i) Prior to venting to the atmosphere, remove process liquids from 
the equipment as much as practical and depressurize the equipment to 
either: A flare meeting the requirements specified in paragraph (e)(4) 
of this section, or a non-flare control device meeting the requirements 
specified in Sec.  63.982(c)(2) of subpart SS, until one of the 
following conditions, as applicable, is met.
    (A) The vapor in the equipment served by the maintenance vent has a 
lower explosive limit (LEL) of less than 10 percent.
    (B) If there is no ability to measure the LEL of the vapor in the 
equipment based on the design of the equipment, the pressure in the 
equipment served by the maintenance vent is reduced to 5 pounds per 
square inch gauge (psig) or less. Upon opening the maintenance vent, 
active purging of the equipment cannot be used until the LEL of the 
vapors in the maintenance vent (or inside the equipment if the 
maintenance is a hatch or similar type of opening) is less than 10 
percent.
    (C) The equipment served by the maintenance vent contains less than 
50 pounds of total volatile organic compounds (VOC).
    (D) If, after applying best practices to isolate and purge 
equipment served by a maintenance vent, none of the applicable 
criterion in paragraphs (e)(5)(i)(A) through (C) of this section can be 
met prior to installing or removing a blind flange or similar equipment 
blind, then the pressure in the equipment served by the maintenance 
vent must be reduced to 2 psig or less before installing or removing 
the equipment blind. During installation or removal of the equipment 
blind, active purging of the equipment may be used provided the 
equipment pressure at the location where purge gas is introduced 
remains at 2 psig or less.
    (ii) Except for maintenance vents complying with the alternative in 
paragraph (e)(5)(i)(C) of this section, the owner or operator must 
determine the LEL or, if applicable, equipment pressure using process 
instrumentation or portable measurement devices and follow procedures 
for calibration and maintenance according to manufacturer's 
specifications.
    (iii) For maintenance vents complying with the alternative in 
paragraph (e)(5)(i)(C) of this section, the owner or operator must 
determine mass of VOC in the equipment served by the maintenance vent 
based on the equipment size and contents after considering any contents 
drained or purged from the equipment. Equipment size may be determined 
from equipment design specifications. Equipment contents may be 
determined using process knowledge.
    (6) Bypass lines. Beginning on the compliance dates specified in 
Sec.  63.1102(c), the use of a bypass line at any time on a closed vent 
system to divert emissions subject to the requirements in Table 7 to 
Sec.  63.1103(e) to the atmosphere or to a control device not meeting 
the requirements specified in Table 7 of this subpart is an emissions 
standards violation. If the owner or operator is subject to the bypass 
monitoring requirements of Sec.  63.983(a)(3) of subpart SS, then the 
owner or operator must continue to comply with the requirements in 
Sec.  63.983(a)(3) of subpart SS and the recordkeeping and reporting 
requirements in Sec. Sec.  63.998(d)(1)(ii) and 63.999(c)(2) of subpart 
SS, in addition to paragraph (e)(9) of this section, the

[[Page 40429]]

recordkeeping requirements specified in Sec.  63.1109(g), and the 
reporting requirements specified in Sec.  63.1110(e)(6). For purposes 
of compliance with this paragraph, the phrase ``Except for equipment 
needed for safety purposes such as pressure relief devices, low leg 
drains, high point bleeds, analyzer vents, and open-ended valves or 
lines'' in Sec.  63.983(a)(3) does not apply; instead, the exemptions 
specified in paragraph (e)(6)(i) and (ii) of this section apply.
    (i) Except for pressure relief devices subject to 40 CFR 
63.1107(h)(4), equipment such as low leg drains and equipment subject 
to the requirements specified in paragraph (f) of Table 7 to Sec.  
63.1103(e) are not subject to this paragraph (e)(6) of this section.
    (ii) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in Sec.  60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as Sec.  60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (e)(6) of this section.
    (7) Decoking operation standards for ethylene cracking furnaces. 
Beginning no later than the compliance dates specified in Sec.  
63.1102(c), the owner or operator must comply with paragraph (e)(7)(i) 
of this section and also use at least two of the control measures 
specified in paragraphs (e)(7)(ii) through (v) of this section to 
minimize coke combustion emissions from the decoking of the radiant 
tube(s) in each ethylene cracking furnace.
    (i) During normal operations, conduct daily inspections of the 
firebox burners and repair all burners that are impinging on the 
radiant tube(s) as soon as practical, but not later than 1 calendar day 
after the flame impingement is found. The owner or operator may delay 
burner repair beyond 1 calendar day using the procedures specified in 
paragraphs (e)(7)(i)(A) and (B) of this section provided the repair 
cannot be completed during normal operations, the burner cannot be 
shutdown without significantly impacting the furnace heat distribution 
and firing rate, and action is taken to reduce flame impingement as 
much as possible during continued operation. An inspection may include, 
but is not limited to: visual inspection of the radiant tube(s) for 
localized bright spots (this may be confirmed with a temperature gun), 
use of luminescent powders injected into the burner to illuminate the 
flame pattern, or identifying continued localized coke build-up that 
causes short runtimes between decoking cycles. A repair may include, 
but is not limited to: Taking the burner out of service, replacing the 
burner, adjusting the alignment of the burner, adjusting burner 
configuration, making burner air corrections, repairing a malfunction 
of the fuel liquid removal equipment, or adding insulation around the 
radiant tube(s).
    (A) If a shutdown for repair would cause greater emissions than the 
potential emissions from delaying repair, repair must be completed 
following the next planned decoking operation (and before returning the 
ethylene cracking furnace back to normal operations) or during the next 
ethylene cracking furnace complete shutdown (when the ethylene cracking 
furnace firebox is taken completely off-line), whichever is earlier.
    (B) If a shutdown for repair would cause lower emissions than the 
potential emissions from delaying repair, then shutdown of the ethylene 
cracking furnace must immediately commence and the repair must be 
completed before returning the ethylene cracking furnace back to normal 
operations.
    (ii) During decoking operations, beginning before the expected end 
of the air-in decoke time, continuously monitor (or use a gas detection 
tube or equivalent sample technique every three hours to monitor) the 
CO2 concentration in the combined decoke effluent downstream 
of the last component being decoked for an indication that the coke 
combustion in the ethylene cracking furnace radiant tube(s) is 
complete. The owner or operator must immediately initiate procedures to 
stop the coke combustion once the CO2 concentration at the 
outlet consistently reaches a level that indicates combustion of coke 
is complete and site decoke completion assurance procedures have been 
concluded.
    (iii) During decoking operations, continuously monitor the 
temperature at the radiant tube(s) outlet when air is being introduced 
to ensure the coke combustion occurring inside the radiant tube(s) is 
not so aggressive (i.e., too hot) that it damages either the radiant 
tube(s) or ethylene cracking furnace isolation valve(s). The owner or 
operator must immediately initiate procedures to reduce the temperature 
at the radiant tube(s) outlet once the temperature reaches a level that 
indicates combustion of coke inside the radiant tube(s) is too 
aggressive.
    (iv) After decoking, but before returning the ethylene cracking 
furnace back to normal operations, verify that decoke air is no longer 
being added.
    (v) After decoking, but before returning the ethylene cracking 
furnace back to normal operations and/or during normal operations, 
inject materials into the steam or feed to reduce coke formation inside 
the radiant tube(s) during normal operation.
    (8) Ethylene cracking furnace isolation valve inspections. 
Beginning no later than the compliance dates specified in Sec.  
63.1102(c), the owner or operator must conduct ethylene cracking 
furnace isolation valve inspections as specified in paragraphs 
(e)(8)(i) and (ii) of this section.
    (i) Prior to decoking operation, inspect the applicable ethylene 
cracking furnace isolation valve(s) to confirm that the radiant tube(s) 
being decoked is completely isolated from the ethylene production 
process so that no emissions generated from decoking operations are 
sent to the ethylene production process. If poor isolation is 
identified, then the owner or operator must rectify the isolation issue 
prior to continuing decoking operations to prevent leaks into the 
ethylene production process.
    (ii) Prior to returning the ethylene cracking furnace to normal 
operations after a decoking operation, inspect the applicable ethylene 
cracking furnace isolation valve(s) to confirm that the radiant tube(s) 
that was decoked is completely isolated from the decoking pot or 
furnace firebox such that no emissions are sent from the radiant 
tube(s) to the decoking pot or furnace firebox once the ethylene 
cracking furnace returns to normal operation. If poor isolation is 
identified, then the owner or operator must rectify the isolation issue 
prior to continuing normal operations to prevent product from escaping 
to the atmosphere through the decoking pot or furnace firebox.
    (9) Startup, shutdown, and malfunction referenced provisions. 
Beginning no later than the compliance dates specified in Sec.  
63.1102(c), the referenced provisions specified in paragraphs (e)(9)(i) 
through (xx) of this section do not apply when demonstrating compliance 
with paragraph (e)(3) of this section.
    (i) The second sentence of Sec.  63.181(d)(5)(i) of subpart H.
    (ii) The second sentence of Sec.  63.983(a)(5) of subpart SS.
    (iii) The phrase ``except during periods of start-up, shutdown and 
malfunction as specified in the referencing subpart'' in Sec.  
63.984(a) of subpart SS.
    (iv) The phrase ``except during periods of start-up, shutdown and 
malfunction as specified in the referencing subpart'' in Sec.  
63.985(a) of subpart SS.

[[Page 40430]]

    (v) The phrase ``other than start-ups, shutdowns, or malfunctions'' 
in Sec.  63.994(c)(1)(ii)(D) of subpart SS.
    (vi) Section 63.996(c)(2)(ii) of subpart SS.
    (vii) The last sentence of Sec.  63.997(e)(1)(i) of subpart SS.
    (viii) Section 63.998(b)(2)(iii) of subpart SS.
    (ix) The phrase ``other than periods of startups, shutdowns, and 
malfunctions'' from Sec.  63.998(b)(5)(i)(A) of subpart SS.
    (x) The phrase ``other than a start-up, shutdown, or malfunction'' 
from Sec.  63.998(b)(5)(i)(B)(3) of subpart SS.
    (xi) The phrase ``other than periods of startups, shutdowns, and 
malfunctions'' from Sec.  63.998(b)(5)(i)(C) of subpart SS.
    (xii) The phrase ``other than a start-up, shutdown, or 
malfunction'' from Sec.  63.998(b)(5)(ii)(C) of subpart SS.
    (xiii) The phrase ``except as provided in paragraphs (b)(6)(i)(A) 
and (B) of this section'' from Sec.  63.998(b)(6)(i) of subpart SS.
    (xiv) The second sentence of Sec.  63.998(b)(6)(ii) of subpart SS.
    (xv) Section 63.998(c)(1)(ii)(D) through (G) of subpart SS.
    (xvi) Section 63.998(d)(3) of subpart SS.
    (xvii) The phrase ``may be included as part of the startup, 
shutdown, and malfunction plan, as required by the referencing subpart 
for the source, or'' from Sec.  63.1024(f)(4)(i) of subpart UU.
    (xviii) The phrase ``(except periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1026(e)(1)(ii)(A) of subpart UU.
    (xix) The phrase ``(except periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1028(e)(1)(i)(A) of subpart UU.
    (xx) The phrase ``(except periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1031(b)(1) of subpart UU.
    (10) Storage vessel degassing. Beginning no later than the 
compliance dates specified in Sec.  63.1102(c), for each storage vessel 
subject to paragraph (b) or (c) of Table 7 to Sec.  63.1103(e), the 
owner or operator must comply with paragraphs (e)(10)(i) through (iii) 
of this section during storage vessel shutdown operations (i.e., 
emptying and degassing of a storage vessel) until the vapor space 
concentration in the storage vessel is less than 10 percent of the LEL. 
The owner or operator must determine the LEL using process 
instrumentation or portable measurement devices and follow procedures 
for calibration and maintenance according to manufacturer's 
specifications.
    (i) Remove liquids from the storage vessel as much as practicable;
    (ii) Comply with one of the following:
    (A) Reduce emissions of total organic HAP by 98 weight-percent by 
venting emissions through a closed vent system to a flare and meet the 
requirements of Sec.  63.983 and paragraphs (e)(4) and (9) of this 
section.
    (B) Reduce emissions of total organic HAP by 98 weight-percent by 
venting emissions through a closed vent system to any combination of 
non-flare control devices and meet the requirements specified in Sec.  
63.982(c)(1) and paragraph (e)(9) of this section.
    (C) Reduce emissions of total organic HAP by 98 weight-percent by 
routing emissions to a fuel gas system or process and meet the 
requirements specified in Sec.  63.982(d) and paragraph (e)(9) of this 
section.
    (iii) Maintain records necessary to demonstrate compliance with the 
requirements in Sec.  63.1108(a)(4)(ii) including, if appropriate, 
records of existing standard site procedures used to empty and degas 
(deinventory) equipment for safety purposes.

   Table 7 to Sec.   63.1103(e)--What Are My Requirements If I Own or
     Operate an Ethylene Production Existing or New Affected Source?
------------------------------------------------------------------------
 If you own or operate . . .      And if . . .       Then you must . . .
------------------------------------------------------------------------
(a) A storage vessel (as      (1) The maximum true  (i) Fill the vessel
 defined in Sec.   63.1101)    vapor pressure of     through a submerged
 that stores liquid            total organic HAP     pipe; or
 containing organic HAP.       is >=3.4             (ii) Comply with the
                               kilopascals but       requirements for
                               <76.6 kilopascals;    storage vessels
                               and the capacity of   with capacities
                               the vessel is >=4     >=95 cubic meters.
                               cubic meters but
                               <95 cubic meters.
(b) A storage vessel (as      (1) The maximum true  (i) Except as
 defined in Sec.   63.1101)    vapor pressure of     specified in
 that stores liquid            total organic HAP     paragraph
 containing organic HAP.       is >=3.4              (b)(1)(iii) of this
                               kilopascals but       table, comply with
                               <76.6 kilopascals;    the requirements of
                               and the capacity of   subpart WW of this
                               the vessel is >=95    part; or
                               cubic meters.        (ii) Except as
                                                     specified in
                                                     paragraph
                                                     (b)(1)(iii) of this
                                                     table, reduce
                                                     emissions of total
                                                     organic HAP by 98
                                                     weight-percent by
                                                     venting emissions
                                                     through a closed
                                                     vent system to any
                                                     combination of
                                                     control devices and
                                                     meet the
                                                     requirements of
                                                     Sec.
                                                     63.982(a)(1).
                                                    (iii) Beginning no
                                                     later than the
                                                     compliance dates
                                                     specified in Sec.
                                                     63.1102(c), comply
                                                     with paragraph
                                                     (b)(1)(iii)(A),
                                                     (B), (C), or (D) of
                                                     this table, and
                                                     (e)(10) of this
                                                     section.
                                                    (A) Comply with the
                                                     requirements of
                                                     subpart WW of this
                                                     part; or
                                                    (B) Reduce emissions
                                                     of total organic
                                                     HAP by 98 weight-
                                                     percent by venting
                                                     emissions through a
                                                     closed vent system
                                                     to a flare and meet
                                                     the requirements of
                                                     Sec.   63.983 and
                                                     paragraphs (e)(4)
                                                     and (9) of this
                                                     section; or
                                                    (C) Reduce emissions
                                                     of total organic
                                                     HAP by 98 weight-
                                                     percent by venting
                                                     emissions through a
                                                     closed vent system
                                                     to any combination
                                                     of non-flare
                                                     control devices and
                                                     meet the
                                                     requirements
                                                     specified in Sec.
                                                     63.982(c)(1) and
                                                     (e)(9) of this
                                                     section; or
                                                    (D) Reduce emissions
                                                     of total organic
                                                     HAP by 98 weight-
                                                     percent by routing
                                                     emissions to a fuel
                                                     gas system\(a)\ or
                                                     process and meet
                                                     the requirements
                                                     specified in Sec.
                                                     63.982(d) and
                                                     (e)(9) of this
                                                     section.

[[Page 40431]]

 
(c) A storage vessel (as      (1) The maximum true  (i) Except as
 defined in Sec.   63.1101)    vapor pressure of     specified in
 that stores liquid            total organic HAP     paragraph
 containing organic HAP.       is >=76.6             (c)(1)(ii) of this
                               kilopascals.          table, reduce
                                                     emissions of total
                                                     organic HAP by 98
                                                     weight-percent by
                                                     venting emissions
                                                     through a closed
                                                     vent system to any
                                                     combination of
                                                     control devices and
                                                     meet the
                                                     requirements of
                                                     Sec.
                                                     63.982(a)(1).
                                                    (ii) Beginning no
                                                     later than the
                                                     compliance dates
                                                     specified in Sec.
                                                     63.1102(c), comply
                                                     with paragraph
                                                     (c)(1)(ii)(A), (B),
                                                     or (C) of this
                                                     table, and (e)(10)
                                                     of this section.
                                                    (A) Reduce emissions
                                                     of total organic
                                                     HAP by 98 weight-
                                                     percent by venting
                                                     emissions through a
                                                     closed vent system
                                                     to a flare and meet
                                                     the requirements of
                                                     Sec.   63.983 and
                                                     paragraphs (e)(4)
                                                     and (9) of this
                                                     section; or
                                                    (B) Reduce emissions
                                                     of total organic
                                                     HAP by 98 weight-
                                                     percent by venting
                                                     emissions through a
                                                     closed vent system
                                                     to any combination
                                                     of non-flare
                                                     control devices and
                                                     meet the
                                                     requirements
                                                     specified in Sec.
                                                     63.982(c)(1) and
                                                     (e)(9) of this
                                                     section; or
                                                    (C) Reduce emissions
                                                     of total organic
                                                     HAP by 98 weight-
                                                     percent by routing
                                                     emissions to a fuel
                                                     gas system\(a)\ or
                                                     process and meet
                                                     the requirements
                                                     specified in Sec.
                                                     63.982(d) and
                                                     (e)(9) of this
                                                     section.
(d) An ethylene process vent  (1) The process vent  (i) Except as
 (as defined in paragraph      is at an existing     specified in
 (e)(2) of this section).      source and the vent   paragraph
                               stream has a flow     (d)(1)(ii) of this
                               rate >=0.011 scmm     table, reduce
                               and a total organic   emissions of
                               HAP concentration     organic HAP by 98
                               >=50 parts per        weight-percent; or
                               million by volume     reduce organic HAP
                               on a dry basis; or    or TOC to a
                               the process vent is   concentration of 20
                               at a new source and   parts per million
                               the vent stream has   by volume on a dry
                               a flow rate >=0.008   basis corrected to
                               scmm and a total      3% oxygen;
                               organic HAP           whichever is less
                               concentration >=30    stringent, by
                               parts per million     venting emissions
                               by volume on a dry    through a closed
                               basis.                vent system to any
                                                     combination of
                                                     control devices and
                                                     meet the
                                                     requirements
                                                     specified in Sec.
                                                     63.982(b) and
                                                     (c)(2).
                                                    (ii) Beginning no
                                                     later than the
                                                     compliance dates
                                                     specified in Sec.
                                                     63.1102(c), comply
                                                     with the
                                                     maintenance vent
                                                     requirements
                                                     specified in
                                                     paragraph (e)(5) of
                                                     this section and
                                                     either paragraph
                                                     (d)(1)(ii)(A) or
                                                     (B) of this table.
                                                    (A) Reduce emissions
                                                     of organic HAP by
                                                     98 weight-percent;
                                                     or reduce organic
                                                     HAP or TOC to a
                                                     concentration of 20
                                                     parts per million
                                                     by volume on a dry
                                                     basis corrected to
                                                     3-percent oxygen;
                                                     whichever is less
                                                     stringent, by
                                                     venting emissions
                                                     through a closed
                                                     vent system to a
                                                     flare and meet the
                                                     requirements of
                                                     Sec.   63.983 and
                                                     paragraphs (e)(4)
                                                     and (9) of this
                                                     section; or
                                                    (B) Reduce emissions
                                                     of organic HAP by
                                                     98 weight-percent;
                                                     or reduce organic
                                                     HAP or TOC to a
                                                     concentration of 20
                                                     parts per million
                                                     by volume on a dry
                                                     basis corrected to
                                                     3-percent oxygen;
                                                     whichever is less
                                                     stringent, by
                                                     venting emissions
                                                     through a closed
                                                     vent system to any
                                                     combination of non-
                                                     flare control
                                                     devices and meet
                                                     the requirements
                                                     specified in Sec.
                                                     63.982(c)(2) and
                                                     (e)(9) of this
                                                     section.
(e) A transfer rack (as       (1) Materials loaded  (i) Reduce emissions
 defined in paragraph (e)(2)   have a true vapor     of organic HAP by
 of this section).             pressure of total     98 weight-percent;
                               organic HAP >=3.4     or reduce organic
                               kilopascals and       HAP or TOC to a
                               >=76 cubic meters     concentration of 20
                               per day (averaged     parts per million
                               over any              by volume on a dry
                               consecutive 30-day    basis corrected to
                               period) of HAP-       3-percent oxygen;
                               containing material   whichever is less
                               is loaded.            stringent, by
                                                     venting emissions
                                                     through a closed
                                                     vent system to any
                                                     combination of
                                                     control devices as
                                                     specified in Sec.
                                                     63.1105 and meet
                                                     the requirements
                                                     specified in
                                                     paragraph (e)(9) of
                                                     this section.; or

[[Page 40432]]

 
                                                    (ii) Install process
                                                     piping designed to
                                                     collect the HAP-
                                                     containing vapors
                                                     displaced from tank
                                                     trucks or railcars
                                                     during loading and
                                                     to route it to a
                                                     process, a fuel gas
                                                     system, or a vapor
                                                     balance system, as
                                                     specified in Sec.
                                                     63.1105 and meet
                                                     the requirements
                                                     specified in
                                                     paragraph (e)(9) of
                                                     this section.\(a)\
(f) Equipment (as defined in  (1) The equipment     (i) Except as
 Sec.   63.1101) that          contains or           specified in
 contains or contacts          contacts >=5 weight-  paragraph
 organic HAP.                  percent organic       (f)(1)(ii) of this
                               HAP; and the          table, comply with
                               equipment is not in   the requirements of
                               vacuum service.       subpart UU of this
                                                     part.
                                                    (ii) Beginning no
                                                     later than the
                                                     compliance dates
                                                     specified in Sec.
                                                     63.1102(c), comply
                                                     with the
                                                     requirements of
                                                     paragraph (e)(9) of
                                                     this section and
                                                     subpart UU of this
                                                     part, except
                                                     instead of
                                                     complying with the
                                                     pressure relief
                                                     device requirements
                                                     of Sec.   63.1030
                                                     of subpart UU, meet
                                                     the requirements of
                                                     Sec.   63.1107(h),
                                                     and in lieu of the
                                                     flare requirement
                                                     of Sec.
                                                     63.1034(b)(2)(iii),
                                                     comply with the
                                                     requirements
                                                     specified in
                                                     paragraph (e)(4) of
                                                     this section.\(a)\
(g) Processes that generate   (1) The waste stream  Comply with the
 waste (as defined in          contains any of the   waste requirements
 paragraph (e)(2) of this      following HAP:        of subpart XX of
 section.                      Benzene, cumene,      this part. For
                               ethyl benzene,        ethylene production
                               hexane,               unit waste stream
                               naphthalene,          requirements, terms
                               styrene, toluene, o-  have the meanings
                               xylene, m-xylene, p-  specified in
                               xylene, or 1,3-       subpart XX.
                               butadiene.
(h) A heat exchange system    ....................  Comply with the heat
 (as defined in Sec.                                 exchange system
 63.1082(b)).                                        requirements of
                                                     subpart XX of this
                                                     part.
(i) A closed vent system      (1) The bypass line   Beginning no later
 that contains one or more     could divert a vent   than the compliance
 bypass lines.                 stream directly to    dates specified in
                               the atmosphere or     Sec.   63.1102(c),
                               to a control device   comply with the
                               not meeting the       requirements
                               requirements in       specified in
                               this table.           paragraphs (e)(6)
                                                     and (9) of this
                                                     section.
(j) A decoking operation      ....................  Beginning no later
 associated with an ethylene                         than the compliance
 cracking furnace.                                   dates specified in
                                                     Sec.   63.1102(c),
                                                     comply with the
                                                     requirements
                                                     specified in
                                                     paragraphs (e)(7)
                                                     and (8) of this
                                                     section.
------------------------------------------------------------------------
\(a)\ Beginning no later than the compliance dates specified in Sec.
  63.1102(c), any flare using fuel gas from a fuel gas system, of which
  50 percent or more of the fuel gas is derived from an ethylene
  production unit as determined on an annual average basis, must be in
  compliance with paragraph (e)(4) of this section.

* * * * *

0
20. Section 63.1104 is amended by revising paragraph (c) to read as 
follows:


Sec.  63.1104   Process vents from continuous unit operations: 
applicability assessment procedures and methods.

* * * * *
    (c) Applicability assessment requirement. The TOC or organic HAP 
concentrations, process vent volumetric flow rates, process vent 
heating values, process vent TOC or organic HAP emission rates, 
halogenated process vent determinations, process vent TRE index values, 
and engineering assessments for process vent control applicability 
assessment requirements are to be determined during maximum 
representative operating conditions for the process, except as provided 
in paragraph (d) of this section, or unless the Administrator specifies 
or approves alternate operating conditions. For acrylic and modacrylic 
fiber production affected sources, polycarbonate production affected 
sources, and ethylene production affected sources, operations during 
periods of malfunction shall not constitute representative conditions 
for the purpose of an applicability test. For all other affected 
sources, operations during periods of startup, shutdown, and 
malfunction shall not constitute representative conditions for the 
purpose of an applicability test.
* * * * *

0
21. Section 63.1105 is amended by revising paragraph (a) introductory 
text and adding paragraph (a)(5) to read as follows:


Sec.  63.1105   Transfer racks.

    (a) Design requirements. Except as specified in paragraph (a)(5) of 
this section, the owner or operator shall equip each transfer rack with 
one of the control options listed in paragraphs (a)(1) through (5) of 
this section.
* * * * *
    (5) Beginning no later than the compliance dates specified in Sec.  
63.1102(c), if emissions are vented through a closed vent system to a 
flare at an ethylene production affected source, then the owner or 
operator must comply with the requirements specified in Sec.  
63.1103(e)(4) instead of the requirements in Sec.  63.987 and the 
provisions regarding flare compliance assessments at Sec.  63.997(a) 
through (c).
* * * * *

0
22. Section 63.1107 is amended by revising paragraph (a) and adding 
paragraph (h) to read as follows:


Sec.  63.1107   Equipment leaks.

    (a) Each piece of equipment within a process unit that can 
reasonably be expected to contain equipment in organic HAP service is 
presumed to be in organic HAP service unless an owner or operator 
demonstrates that the piece of equipment is not in organic HAP service. 
For a piece of equipment to be considered not in organic HAP service, 
it must be determined that the percent organic HAP content can be 
reasonably expected not to exceed the percent by weight control 
applicability criteria specified in Sec.  63.1103 for an affected 
source on an annual average basis. For purposes of determining the 
percent

[[Page 40433]]

organic HAP content of the process fluid that is contained in or 
contacts equipment, Method 18 of 40 CFR part 60, appendix A shall be 
used. For purposes of determining the percent organic HAP content of 
the process fluid that is contained in or contacts equipment for the 
ethylene production affected sources, the following methods shall be 
used for equipment: For equipment in gas and vapor service, as that 
term is defined in Subpart UU of this part, shall use Method 18 of 40 
CFR part 60, appendix A; for equipment in liquid service, as that term 
is defined in Subpart UU of this part, shall use a combination of 
Method 18 of 40 CFR part 60, appendix A, SW-846-8260B (incorporated by 
reference, see Sec.  63.14); and SW-846-8270D (incorporated by 
reference, see Sec.  63.14), as appropriate.
* * * * *
    (h) Ethylene production pressure release requirements. Beginning no 
later than the compliance dates specified in Sec.  63.1102(c), except 
as specified in paragraph (h)(4) of this section, owners or operators 
of ethylene production affected sources must comply with the 
requirements specified in paragraphs (h)(1) and (2) of this section for 
pressure relief devices, such as relief valves or rupture disks, in 
organic HAP gas or vapor service instead of the pressure relief device 
requirements of Sec.  63.1030 of subpart UU or Sec.  63.165 of subpart 
H. Beginning no later than the compliance dates specified in Sec.  
63.1102(c), except as specified in paragraphs (h)(4) and (5) of this 
section, the owner or operator must also comply with the requirements 
specified in paragraphs (h)(3) and (6) through (8) of this section for 
all pressure relief devices.
    (1) Operating requirements. Except during a pressure release, 
operate each pressure relief device in organic HAP gas or vapor service 
with an instrument reading of less than 500 ppm above background as 
measured by the method in Sec.  63.1023(b) of subpart UU or Sec.  
63.180(b) and (c) of subpart H.
    (2) Pressure release requirements. For pressure relief devices in 
organic HAP gas or vapor service, the owner or operator must comply 
with the applicable requirements in paragraphs (h)(2)(i) through (iii) 
of this section following a pressure release.
    (i) If the pressure relief device does not consist of or include a 
rupture disk, conduct instrument monitoring, as specified in Sec.  
63.1023(b) of subpart UU or Sec.  63.180(b) and (c) of subpart H, no 
later than 5 calendar days after the pressure relief device returns to 
organic HAP gas or vapor service following a pressure release to verify 
that the pressure relief device is operating with an instrument reading 
of less than 500 ppm.
    (ii) If the pressure relief device includes a rupture disk, either 
comply with the requirements in paragraph (h)(2)(i) of this section 
(and do not replace the rupture disk) or install a replacement disk as 
soon as practicable after a pressure release, but no later than 5 
calendar days after the pressure release.
    (iii) If the pressure relief device consists only of a rupture 
disk, install a replacement disk as soon as practicable after a 
pressure release, but no later than 5 calendar days after the pressure 
release. The owner or operator must not initiate startup of the 
equipment served by the rupture disk until the rupture disc is 
replaced.
    (3) Pressure release management. Except as specified in paragraphs 
(h)(4) and (5) of this section, the owner or operator must comply with 
the requirements specified in paragraphs (h)(3)(i) through (v) of this 
section for all pressure relief devices in organic HAP service.
    (i) The owner or operator must equip each affected pressure relief 
device with a device(s) or use a monitoring system that is capable of:
    (A) Identifying the pressure release;
    (B) Recording the time and duration of each pressure release; and
    (C) Notifying operators immediately that a pressure release is 
occurring. The device or monitoring system must be either specific to 
the pressure relief device itself or must be associated with the 
process system or piping, sufficient to indicate a pressure release to 
the atmosphere. Examples of these types of devices and systems include, 
but are not limited to, a rupture disk indicator, magnetic sensor, 
motion detector on the pressure relief valve stem, flow monitor, or 
pressure monitor.
    (ii) The owner or operator must apply at least three redundant 
prevention measures to each affected pressure relief device and 
document these measures. Examples of prevention measures include:
    (A) Flow, temperature, liquid level and pressure indicators with 
deadman switches, monitors, or automatic actuators. Independent, non-
duplicative systems within this category count as separate redundant 
prevention measures.
    (B) Documented routine inspection and maintenance programs and/or 
operator training (maintenance programs and operator training may count 
as only one redundant prevention measure).
    (C) Inherently safer designs or safety instrumentation systems.
    (D) Deluge systems.
    (E) Staged relief system where the initial pressure relief device 
(with lower set release pressure) discharges to a flare or other closed 
vent system and control device.
    (iii) If any affected pressure relief device releases to atmosphere 
as a result of a pressure release event, the owner or operator must 
perform root cause analysis and corrective action analysis according to 
the requirement in paragraph (h)(6) of this section and implement 
corrective actions according to the requirements in paragraph (h)(7) of 
this section. The owner or operator must also calculate the quantity of 
organic HAP released during each pressure release event and report this 
quantity as required in Sec.  63.1110(e)(8)(iii). Calculations may be 
based on data from the pressure relief device monitoring alone or in 
combination with process parameter monitoring data and process 
knowledge.
    (iv) The owner or operator must determine the total number of 
release events that occurred during the calendar year for each affected 
pressure relief device separately. The owner or operator must also 
determine the total number of release events for each pressure relief 
device for which the root cause analysis concluded that the root cause 
was a force majeure event, as defined in Sec.  63.1103(e)(2).
    (v) Except for pressure relief devices described in paragraphs 
(h)(4) and (5) of this section, the following release events from an 
affected pressure relief device are a violation of the pressure release 
management work practice standards.
    (A) Any release event for which the root cause of the event was 
determined to be operator error or poor maintenance.
    (B) A second release event not including force majeure events from 
a single pressure relief device in a 3-calendar year period for the 
same root cause for the same equipment.
    (C) A third release event not including force majeure events from a 
single pressure relief device in a 3-calendar year period for any 
reason.
    (4) Pressure relief devices routed to a control device, process, 
fuel gas system, or drain system. (i) If all releases and potential 
leaks from a pressure relief device are routed through a closed vent 
system to a control device, back into the process, a fuel gas system, 
or drain system, then the owner or operator is not required to comply 
with paragraph (h)(1), (2), or (3) of this section.
    (ii) Before the compliance dates specified in Sec.  63.1102(c), 
both the

[[Page 40434]]

closed vent system and control device (if applicable) referenced in 
paragraph (h)(4)(i) of this section must meet the applicable 
requirements specified in Sec.  63.982(b) and (c)(2). Beginning no 
later than the compliance dates specified in Sec.  63.1102(c), both the 
closed vent system and control device (if applicable) referenced in 
paragraph (h)(4)(i) of this section must meet the applicable 
requirements specified in Sec. Sec.  63.982(c)(2), 63.983, and 
63.1103(e)(4). For purposes of compliance with this paragraph, the 
phrase ``Except for equipment needed for safety purposes such as 
pressure relief devices'' in Sec.  63.983(a)(3) does not apply.
    (iii) The drain system (if applicable) referenced in paragraph 
(h)(4)(i) of this section must meet the applicable requirements 
specified in Sec.  61.346 or Sec.  63.136.
    (5) Pressure relief devices exempted from pressure release 
management requirements. The following types of pressure relief devices 
are not subject to the pressure release management requirements in 
paragraph (h)(3) of this section.
    (i) Pressure relief devices in heavy liquid service, as defined in 
Sec.  63.1020 of subpart UU.
    (ii) Thermal expansion relief valves.
    (iii) Pressure relief devices on mobile equipment.
    (iv) Pilot-operated pressure relief devices where the primary 
release valve is routed through a closed vent system to a control 
device or back into the process, a fuel gas system, or drain system.
    (v) Balanced bellows pressure relief devices where the primary 
release valve is routed through a closed vent system to a control 
device or back into the process, a fuel gas system, or drain system.
    (6) Root cause analysis and corrective action analysis. A root 
cause analysis and corrective action analysis must be completed as soon 
as possible, but no later than 45 days after a release event. Special 
circumstances affecting the number of root cause analyses and/or 
corrective action analyses are provided in paragraphs (h)(6)(i) through 
(iv) of this section.
    (i) You may conduct a single root cause analysis and corrective 
action analysis for a single emergency event that causes two or more 
pressure relief devices that are installed on the same equipment to 
release.
    (ii) You may conduct a single root cause analysis and corrective 
action analysis for a single emergency event that causes two or more 
pressure relief devices to release, regardless of the equipment served, 
if the root cause is reasonably expected to be a force majeure event, 
as defined in Sec.  63.1103(e)(2).
    (iii) Except as provided in paragraphs (h)(6)(i) and (ii) of this 
section, if more than one pressure relief device has a release during 
the same time period, an initial root cause analysis must be conducted 
separately for each pressure relief device that had a release. If the 
initial root cause analysis indicates that the release events have the 
same root cause(s), the initial separate root cause analyses may be 
recorded as a single root cause analysis and a single corrective action 
analysis may be conducted.
    (7) Corrective action implementation. Each owner or operator 
required to conduct a root cause analysis and corrective action 
analysis as specified in paragraphs (h)(3)(iii) and (6) of this 
section, must implement the corrective action(s) identified in the 
corrective action analysis in accordance with the applicable 
requirements in paragraphs (h)(7)(i) through (iii) of this section.
    (i) All corrective action(s) must be implemented within 45 days of 
the event for which the root cause and corrective action analyses were 
required or as soon thereafter as practicable. If an owner or operator 
concludes that no corrective action should be implemented, the owner or 
operator must record and explain the basis for that conclusion no later 
than 45 days following the event.
    (ii) For corrective actions that cannot be fully implemented within 
45 days following the event for which the root cause and corrective 
action analyses were required, the owner or operator must develop an 
implementation schedule to complete the corrective action(s) as soon as 
practicable.
    (iii) No later than 45 days following the event for which a root 
cause and corrective action analyses were required, the owner or 
operator must record the corrective action(s) completed to date, and, 
for action(s) not already completed, a schedule for implementation, 
including proposed commencement and completion dates.
    (8) Flowing pilot-operated pressure relief devices. For ethylene 
production affected sources that commenced construction or 
reconstruction on or before October 9, 2019, owners or operators are 
prohibited from installing a flowing pilot-operated pressure relief 
device or replacing any pressure relief device with a flowing pilot-
operated pressure relief device after July 6, 2023. For ethylene 
production affected sources that commenced construction or 
reconstruction after October 9, 2019, owners or operators are 
prohibited from installing and operating flowing pilot-operated 
pressure relief devices. For purpose of compliance with this paragraph, 
a flowing pilot-operated pressure relief device means the type of 
pilot-operated pressure relief device where the pilot discharge vent 
continuously releases emissions to the atmosphere when the pressure 
relief device is actuated.

0
23. Section 63.1108 is amended by revising paragraphs (a) introductory 
text, (a)(4), (b)(1)(ii), (b)(2) introductory text, (b)(3), (b)(4)(i) 
introductory text, and (b)(4)(ii)(B) to read as follows:


Sec.  63.1108   Compliance with standards and operation and maintenance 
requirements.

    (a) Requirements. The requirements of paragraphs (a)(1), (2), and 
(5) of this section apply to all affected sources except acrylic and 
modacrylic fiber production affected sources, polycarbonate production 
affected sources, and beginning no later than the compliance dates 
specified in Sec.  63.1102(c), ethylene production affected sources. 
The requirements of paragraph (a)(4) of this section apply only to 
acrylic and modacrylic fiber production affected sources, polycarbonate 
production affected sources and beginning no later than the compliance 
dates specified in Sec.  63.1102(c), ethylene production affected 
sources. The requirements of paragraphs (a)(3), (6), and (7) of this 
section apply to all affected sources.
* * * * *
    (4)(i) For acrylic and modacrylic fiber production affected sources 
and polycarbonate production affected sources, and beginning no later 
than the compliance dates specified in Sec.  63.1102(c), ethylene 
production affected sources, the emission limitations and established 
parameter ranges of this part shall apply at all times except during 
periods of non-operation of the affected source (or specific portion 
thereof) resulting in cessation of the emissions to which this subpart 
applies. Equipment leak requirements shall apply at all times except 
during periods of non-operation of the affected source (or specific 
portion thereof) in which the lines are drained and depressurized 
resulting in cessation of the emissions to which the equipment leak 
requirements apply.
    (ii) At all times, the owner or operator 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

[[Page 40435]]

to minimize emissions does not require the owner or operator to make 
any further efforts to reduce emissions if levels required by the 
applicable standard have been achieved. Determination 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 affected 
source.
* * * * *
    (b) * * *
    (1) * * *
    (ii) Excused excursions are not allowed for acrylic and modacrylic 
fiber production affected sources, polycarbonate production affected 
sources, and beginning no later than the compliance dates specified in 
Sec.  63.1102(c), ethylene production affected sources. For all other 
affected sources, including ethylene production affected sources prior 
to the compliance dates specified in Sec.  63.1102(c), an excused 
excursion, as described in Sec.  63.998(b)(6)(ii), is not a violation.
    (2) Parameter monitoring: Excursions. An excursion is not a 
violation in cases where continuous monitoring is required and the 
excursion does not count toward the number of excused excursions (as 
described in Sec.  63.998(b)(6)(ii)), if the conditions of paragraph 
(b)(2)(i) or (ii) of this section are met, except that the conditions 
of paragraph (b)(2)(i) of this section do not apply for acrylic and 
modacrylic fiber production affected sources, polycarbonate production 
affected sources, and beginning no later than the compliance dates 
specified in Sec.  63.1102(c), ethylene production affected sources. 
Nothing in this paragraph shall be construed to allow or excuse a 
monitoring parameter excursion caused by any activity that violates 
other applicable provisions of this subpart or a subpart referenced by 
this subpart.
* * * * *
    (3) Operation and maintenance procedures. Determination of whether 
acceptable operation and maintenance procedures are being used will be 
based on information available to the Administrator. This information 
may include, but is not limited to, monitoring results, review of 
operation and maintenance procedures (including the startup, shutdown, 
and malfunction plan under Sec.  63.1111, if applicable), review of 
operation and maintenance records, and inspection of the affected 
source, and alternatives approved as specified in Sec.  63.1113.
    (4) * * *
    (i) Applicability assessments. Unless otherwise specified in a 
relevant test method required to assess control applicability, each 
test shall consist of three separate runs using the applicable test 
method. Each run shall be conducted for the time and under the 
conditions specified in this subpart. The arithmetic mean of the 
results of the three runs shall apply when assessing applicability. 
Upon receiving approval from the Administrator, results of a test run 
may be replaced with results of an additional test run if it meets the 
criteria specified in paragraphs (b)(4)(i)(A) through (D) of this 
section.
* * * * *
    (ii) * * *
    (B) For acrylic and modacrylic fiber production affected sources, 
polycarbonate production affected sources, and beginning no later than 
the compliance dates specified in Sec.  63.1102(c), ethylene production 
affected sources, performance tests shall be conducted under such 
conditions as the Administrator specifies to the owner or operator 
based on representative performance of the affected source for the 
period being tested. Representative conditions exclude periods of 
startup and shutdown unless specified by the Administrator or an 
applicable subpart. The owner or operator may not conduct performance 
tests during periods of malfunction. The owner or operator must 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 normal operation. Upon request, 
the owner or operator shall make available to the Administrator such 
records as may be necessary to determine the conditions of performance 
tests.
* * * * *

0
24. Section 63.1109 is amended by adding paragraphs (e) through (i) to 
read as follows:


Sec.  63.1109   Recordkeeping requirements.

* * * * *
    (e) Ethylene production flare records. For each flare subject to 
the requirements in Sec.  63.1103(e)(4), owners or operators must keep 
records specified in paragraphs (e)(1) through (15) of this section in 
lieu of the information required in Sec.  63.998(a)(1) of subpart SS.
    (1) Retain records of the output of the monitoring device used to 
detect the presence of a pilot flame or flare flame as required in 
Sec.  63.670(b) of subpart CC and the presence of a pilot flame as 
required in Sec.  63.1103(e)(4)(vii)(D) for a minimum of 2 years. 
Retain records of each 15-minute block during which there was at least 
one minute that no pilot flame or flare flame is present when regulated 
material is routed to a flare for a minimum of 5 years. For each 
pressure-assisted multi-point flare that uses cross-lighting, retain 
records of each 15-minute block during which there was at least one 
minute that no pilot flame is present on each stage when regulated 
material is routed to a flare for a minimum of 5 years. You may reduce 
the collected minute-by-minute data to a 15-minute block basis with an 
indication of whether there was at least one minute where no pilot 
flame or flare flame was present.
    (2) Retain records of daily visible emissions observations as 
specified in paragraphs (e)(2)(i) through (iv) of this section, as 
applicable, for a minimum of 3 years.
    (i) To determine when visible emissions observations are required, 
the record must identify all periods when regulated material is vented 
to the flare.
    (ii) If visible emissions observations are performed using Method 
22 of 40 CFR part 60, appendix A-7, then the record must identify 
whether the visible emissions observation was performed, the results of 
each observation, total duration of observed visible emissions, and 
whether it was a 5-minute or 2-hour observation. Record the date and 
start time of each visible emissions observation.
    (iii) If a video surveillance camera is used pursuant to Sec.  
63.670(h)(2) of subpart CC, then the record must include all video 
surveillance images recorded, with time and date stamps.
    (iv) For each 2-hour period for which visible emissions are 
observed for more than 5 minutes in 2 consecutive hours, then the 
record must include the date and start and end time of the 2-hour 
period and an estimate of the cumulative number of minutes in the 2-
hour period for which emissions were visible.
    (3) The 15-minute block average cumulative flows for flare vent gas 
and, if applicable, total steam, perimeter assist air, and premix 
assist air specified to be monitored under Sec.  63.670(i) of subpart 
CC, along with the date and time interval for the 15-minute block. If 
multiple monitoring locations are used to determine cumulative vent gas 
flow, total steam, perimeter assist air, and premix assist air, then 
retain records of the 15-minute block average flows for each monitoring 
location for a minimum of 2 years, and retain records of the 15-minute 
block average cumulative flows that are used in subsequent calculations

[[Page 40436]]

for a minimum of 5 years. If pressure and temperature monitoring is 
used, then retain records of the 15-minute block average temperature, 
pressure, and molecular weight of the flare vent gas or assist gas 
stream for each measurement location used to determine the 15-minute 
block average cumulative flows for a minimum of 2 years, and retain 
records of the 15-minute block average cumulative flows that are used 
in subsequent calculations for a minimum of 5 years.
    (4) The flare vent gas compositions specified to be monitored under 
Sec.  63.670(j) of subpart CC. Retain records of individual component 
concentrations from each compositional analysis for a minimum of 2 
years. If an NHVvg analyzer is used, retain records of the 15-minute 
block average values for a minimum of 5 years.
    (5) Each 15-minute block average operating parameter calculated 
following the methods specified in Sec.  63.670(k) through (n) of 
subpart CC, as applicable.
    (6) All periods during which operating values are outside of the 
applicable operating limits specified in Sec.  63.670(d) through (f) of 
subpart CC and Sec.  63.1103(e)(4)(vii) when regulated material is 
being routed to the flare.
    (7) All periods during which the owner or operator does not perform 
flare monitoring according to the procedures in Sec.  63.670(g) through 
(j) of subpart CC.
    (8) For pressure-assisted multi-point flares, if a stage of burners 
on the flare uses cross-lighting, then a record of any changes made to 
the distance between burners.
    (9) For pressure-assisted multi-point flares, all periods when the 
pressure monitor(s) on the main flare header show burners are operating 
outside the range of the manufacturer's specifications. Indicate the 
date and time for each period, the pressure measurement, the stage(s) 
and number of burners affected, and the range of manufacturer's 
specifications.
    (10) For pressure-assisted multi-point flares, all periods when the 
staging valve position indicator monitoring system indicates a stage of 
the pressure-assisted multi-point flare should not be in operation and 
when a stage of the pressure-assisted multi-point flare should be in 
operation and is not. Indicate the date and time for each period, 
whether the stage was supposed to be open, but was closed or vice 
versa, and the stage(s) and number of burners affected.
    (11) Records of periods when there is flow of vent gas to the 
flare, but when there is no flow of regulated material to the flare, 
including the start and stop time and dates of periods of no regulated 
material flow.
    (12) Records when the flow of vent gas exceeds the smokeless 
capacity of the flare, including start and stop time and dates of the 
flaring event.
    (13) Records of the root cause analysis and corrective action 
analysis conducted as required in Sec.  63.670(o)(3) of subpart CC and 
Sec.  63.1103(e)(4)(iv), including an identification of the affected 
flare, the date and duration of the event, a statement noting whether 
the event resulted from the same root cause(s) identified in a previous 
analysis and either a description of the recommended corrective 
action(s) or an explanation of why corrective action is not necessary 
under Sec.  63.670(o)(5)(i) of subpart CC.
    (14) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.670(o)(5) of subpart CC, a 
description of the corrective action(s) completed within the first 45 
days following the discharge and, for action(s) not already completed, 
a schedule for implementation, including proposed commencement and 
completion dates.
    (15) Records described in Sec.  63.10(b)(2)(vi).
    (f) Ethylene production maintenance vent records. For each 
maintenance vent opening subject to the requirements in Sec.  
63.1103(e)(5), the owner or operator must keep the applicable records 
specified in (f)(1) through (5) of this section.
    (1) The owner or operator must maintain standard site procedures 
used to deinventory equipment for safety purposes (e.g., hot work or 
vessel entry procedures) to document the procedures used to meet the 
requirements in Sec.  63.1103(e)(5). The current copy of the procedures 
must be retained and available on-site at all times. Previous versions 
of the standard site procedures, as applicable, must be retained for 5 
years.
    (2) If complying with the requirements of Sec.  63.1103(e)(5)(i)(A) 
and the LEL at the time of the vessel opening exceeds 10 percent, 
records that identify the maintenance vent, the process units or 
equipment associated with the maintenance vent, the date of maintenance 
vent opening, and the LEL at the time of the vessel opening.
    (3) If complying with the requirements of Sec.  63.1103(e)(5)(i)(B) 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the LEL at the time of the active purging was 
initiated exceeds 10 percent, records that identify the maintenance 
vent, the process units or equipment associated with the maintenance 
vent, the date of maintenance vent opening, the pressure of the vessel 
or equipment at the time of discharge to the atmosphere and, if 
applicable, the LEL of the vapors in the equipment when active purging 
was initiated.
    (4) If complying with the requirements of Sec.  
63.1103(e)(5)(i)(C), records of the estimating procedures used to 
determine the total quantity of VOC in equipment and the type and size 
limits of equipment that contain less than 50 pounds of VOC at the time 
of maintenance vent opening. For each maintenance vent opening of 
equipment that contains greater than 50 pounds of VOC for which the 
deinventory procedures specified in paragraph (f)(1) of this section 
are not followed or for which the equipment opened exceeds the type and 
size limits established in the records specified in this paragraph, 
records that identify the maintenance vent, the process units or 
equipment associated with the maintenance vent, the date of maintenance 
vent opening, and records used to estimate the total quantity of VOC in 
the equipment at the time the maintenance vent was opened to the 
atmosphere.
    (5) If complying with the requirements of Sec.  
63.1103(e)(5)(i)(D), identification of the maintenance vent, the 
process units or equipment associated with the maintenance vent, 
records documenting actions taken to comply with other applicable 
alternatives and why utilization of this alternative was required, the 
date of maintenance vent opening, the equipment pressure and LEL of the 
vapors in the equipment at the time of discharge, an indication of 
whether active purging was performed and the pressure of the equipment 
during the installation or removal of the blind if active purging was 
used, the duration the maintenance vent was open during the blind 
installation or removal process, and records used to estimate the total 
quantity of VOC in the equipment at the time the maintenance vent was 
opened to the atmosphere for each applicable maintenance vent opening.
    (g) Ethylene production bypass line records. For each flow event 
from a bypass line subject to the requirements in Sec.  63.1103(e)(6), 
the owner or operator must maintain records sufficient to determine 
whether or not the detected flow included flow requiring control. For 
each flow event from a bypass line requiring control that is released 
either directly to the atmosphere or to a control device not meeting 
the requirements specified in Table 7 to Sec.  63.1103(e), the owner or 
operator must include an estimate of the volume of

[[Page 40437]]

gas, the concentration of organic HAP in the gas and the resulting 
emissions of organic HAP that bypassed the control device using process 
knowledge and engineering estimates.
    (h) Decoking operation of ethylene cracking furnace records. For 
each decoking operation of an ethylene cracking furnace subject to the 
standards in Sec.  63.1103(e)(7) and (8), the owner or operator must 
keep the records specified in paragraphs (h)(1) through (6) of this 
section.
    (1) Records that document the day and time each inspection 
specified in Sec.  63.1103(e)(7)(i) took place, the results of each 
inspection, and any repairs made to correct the flame impingement; and 
for any repair that is delayed beyond 1 calendar day, the records 
specified in paragraphs (h)(1)(i) through (iii) of this section.
    (i) The reason for the delay.
    (ii) An estimate of the emissions from shutdown for repair and an 
estimate of the emissions likely to result from delay of repair, and 
whether the requirements at Sec.  63.1103(e)(7)(i)(A) or (B) were met.
    (iii) The date the repair was completed or, if the repair has not 
been completed, a schedule for completing the repair.
    (2) If the owner or operator chooses to monitor the CO2 
concentration during decoking as specified in Sec.  63.1103(e)(7)(ii), 
then for each decoking cycle, records must be kept for all measured 
CO2 concentration values beginning before the expected end 
of the air-in decoke time, the criterion used to begin the 
CO2 monitoring, and the target used to indicate combustion 
is complete. The target record should identify any time period the site 
routinely extends air addition beyond the specified CO2 
concentration and any decoke completion assurance procedures used to 
confirm all coke has been removed prior to stopping air addition that 
occurs after the CO2 target is reached.
    (3) If the owner or operator chooses to monitor the temperature at 
the radiant tube(s) outlet during decoking as specified in Sec.  
63.1103(e)(7)(iii), then for each decoking cycle, records must be kept 
for all measured temperature values and the target used to indicate a 
reduction in temperature of the inside of the radiant tube(s) is 
necessary.
    (4) If the owner or operator chooses to comply with Sec.  
63.1103(e)(7)(iv), then records must be kept that document that decoke 
air is no longer being added after each decoking cycle.
    (5) If the owner or operator chooses to treat steam or feed to 
reduce coke formation as specified in Sec.  63.1103(e)(7)(v), then 
records must be kept that document that the planned treatment occurred.
    (6) For each decoking operation of an ethylene cracking furnace 
subject to the requirements in Sec.  63.1103(e)(8), the owner or 
operator must keep records that document the day each inspection took 
place and the results of each inspection where an isolation problem was 
identified including any repairs made to correct the problem.
    (i) Ethylene production pressure relief devices records. For each 
pressure relief device subject to the pressure release management work 
practice standards in Sec.  63.1107(h)(3), the owner or operator must 
keep the records specified in paragraphs (i)(1) through (3) of this 
section.
    (1) Records of the prevention measures implemented as required in 
Sec.  63.1107(h)(3)(ii).
    (2) Records of the number of releases during each calendar year and 
the number of those releases for which the root cause was determined to 
be a force majeure event. Keep these records for the current calendar 
year and the past five calendar years.
    (3) For each release to the atmosphere, the owner or operator must 
keep the records specified in paragraphs (i)(3)(i) through (iv) of this 
section.
    (i) The start and end time and date of each pressure release to the 
atmosphere.
    (ii) Records of any data, assumptions, and calculations used to 
estimate of the mass quantity of each organic HAP released during the 
event.
    (iii) Records of the root cause analysis and corrective action 
analysis conducted as required in Sec.  63.1107(h)(3)(iii), including 
an identification of the affected pressure relief device, a statement 
noting whether the event resulted from the same root cause(s) 
identified in a previous analysis and either a description of the 
recommended corrective action(s) or an explanation of why corrective 
action is not necessary under Sec.  63.1107(h)(7)(i).
    (iv) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.1107(h)(7), a description 
of the corrective action(s) completed within the first 45 days 
following the discharge and, for action(s) not already completed, a 
schedule for implementation, including proposed commencement and 
completion dates.

0
25. Section 63.1110 is amended by:
0
a. Revising paragraphs (a) introductory text, (a)(7), and (a)(9) 
introductory text;
0
b. Adding paragraph (a)(10);
0
c. Revising paragraphs (d)(1) introductory text and (d)(1)(i);
0
d. Adding paragraphs (d)(1)(iv) and (v);
0
e. Revising paragraph (e)(1);
0
f. Adding paragraphs (e)(4) through (8); and
0
g. Revising paragraphs (g)(1) and (2).
    The revisions and additions read as follows:


Sec.  63.1110   Reporting requirements.

    (a) Required reports. Each owner or operator of an affected source 
subject to this subpart shall submit the reports listed in paragraphs 
(a)(1) through (8) of this section, as applicable. Each owner or 
operator of an acrylic and modacrylic fiber production affected source 
or polycarbonate production affected source subject to this subpart 
shall also submit the reports listed in paragraph (a)(9) of this 
section in addition to the reports listed in paragraphs (a)(1) through 
(8) of this section, as applicable. Beginning no later than the 
compliance dates specified in Sec.  63.1102(c), each owner or operator 
of an ethylene production affected source subject to this subpart shall 
also submit the reports listed in paragraph (a)(10) of this section in 
addition to the reports listed in paragraphs (a)(1) through (8) of this 
section, as applicable.
* * * * *
    (7) Startup, Shutdown, and Malfunction Reports described in Sec.  
63.1111 (except for acrylic and modacrylic fiber production affected 
sources, ethylene production affected sources, and polycarbonate 
production affected sources).
* * * * *
    (9) Within 60 days after the date of completing each performance 
test (as defined in Sec.  63.2), the owner or operator must submit the 
results of the performance tests, including any associated fuel 
analyses, required by this subpart according to the methods specified 
in paragraph (a)(9)(i) or (ii) of this section.
* * * * *
    (10)(i) Beginning no later than the compliance dates specified in 
Sec.  63.1102(c), within 60 days after the date of completing each 
performance test required by this subpart, the owner or operator must 
submit the results of the performance test following the procedures 
specified in paragraphs (a)(10)(i)(A) through (C) of this section.
    (A) Data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT website 
(https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test. Submit the results of the 
performance test to the EPA via

[[Page 40438]]

CEDRI, which can be accessed through the EPA's CDX (https://cdx.epa.gov/). The data must be submitted in a file format generated 
through the use of the EPA's ERT. Alternatively, you may submit an 
electronic file consistent with the extensible markup language (XML) 
schema listed on the EPA's ERT website.
    (B) Data collected using test methods that are not supported by the 
EPA's ERT as listed on the EPA's ERT website at the time of the test. 
The results of the performance test must be included as an attachment 
in the ERT or an alternate electronic file consistent with the XML 
schema listed on the EPA's ERT website. Submit the ERT generated 
package or alternative file to the EPA via CEDRI.
    (C) CBI. If you claim some of the information submitted under 
paragraph (a)(10)(i)(A) or (B) of this section is CBI, then the owner 
or operator must submit a complete file, including information claimed 
to be CBI, to the EPA. The file must be generated through the use of 
the EPA's ERT or an alternate electronic file consistent with the XML 
schema listed on the EPA's ERT website. Submit the file on a compact 
disc, flash drive, or other commonly used electronic storage medium and 
clearly mark the medium as CBI. Mail the electronic medium to U.S. EPA/
OAQPS/CORE CBI Office, Attention: Group Leader, Measurement Policy 
Group, MD C404-02, 4930 Old Page Rd., Durham, NC 27703. The same file 
with the CBI omitted must be submitted to the EPA via EPA's CDX as 
described in paragraphs (a)(10)(i)(A) and (B) of this section.
    (ii) Beginning no later than the compliance dates specified in 
Sec.  63.1102(c), the owner or operator must submit all subsequent 
Notification of Compliance Status reports required under paragraph 
(a)(4) of this section in PDF format to the EPA via CEDRI, which can be 
accessed through EPA's CDX (https://cdx.epa.gov/). All subsequent 
Periodic Reports required under paragraph (a)(5) of this section must 
be submitted to the EPA via CEDRI using the appropriate electronic 
report template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/compliance-and-emissions-data-reporting-interface-cedri) for this subpart beginning no later than the 
compliance dates specified in Sec.  63.1102(c) or once the report 
template has been available on the CEDRI website for one year, 
whichever date is later. The date report templates become available 
will be listed on the CEDRI website. The report must be submitted by 
the deadline specified in this subpart, regardless of the method in 
which the report is submitted. If you claim some of the information 
required to be submitted via CEDRI is CBI, then submit a complete 
report, including information claimed to be CBI, to the EPA. Periodic 
Reports must be generated using the appropriate template on the CEDRI 
website. Submit the file on a compact disc, flash drive, or other 
commonly used electronic storage medium and clearly mark the medium as 
CBI. Mail the electronic medium to U.S. Environmental Protection 
Agency, Office of Air Quality Planning and Standards, Sector Policies 
and Programs Division, U.S. EPA Mailroom (E143-01), Attention: Ethylene 
Production Sector Lead, 109 T.W. Alexander Drive, Research Triangle 
Park, NC 27711. The same file with the CBI omitted must be submitted to 
the EPA via the EPA's CDX as described earlier in this paragraph.
    (iii) If you are required to electronically submit a report through 
CEDRI in the EPA's CDX, you may assert a claim of EPA system outage for 
failure to timely comply with the reporting requirement. To assert a 
claim of EPA system outage, the owner or operator must meet the 
requirements outlined in paragraphs (a)(10)(iii)(A) through (G) of this 
section.
    (A) The owner or operator must have been or will be precluded from 
accessing CEDRI and submitting a required report within the time 
prescribed due to an outage of either the EPA's CEDRI or CDX systems.
    (B) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (C) The outage may be planned or unplanned.
    (D) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date you 
first knew, or through due diligence should have known, that the event 
may cause or has caused a delay in reporting.
    (E) The owner or operator must provide to the Administrator a 
written description identifying:
    (1) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (2) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (3) Measures taken or to be taken to minimize the delay in 
reporting; and
    (4) The date by which you propose to report, or if you have already 
met the reporting requirement at the time of the notification, the date 
you reported.
    (F) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (G) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (iv) If you are required to electronically submit a report through 
CEDRI in the EPA's CDX, you may assert a claim of force majeure for 
failure to timely comply with the reporting requirement. To assert a 
claim of force majeure, the owner or operator must meet the 
requirements outlined in paragraphs (a)(10)(iv)(A) through (E) of this 
section.
    (A) You may submit a claim if a force majeure event is about to 
occur, occurs, or has occurred or there are lingering effects from such 
an event within the period of time beginning five business days prior 
to the date the submission is due. For the purposes of this paragraph, 
a force majeure event is defined as an event that will be or has been 
caused by circumstances beyond the control of the affected facility, 
its contractors, or any entity controlled by the affected facility that 
prevents you from complying with the requirement to submit a report 
electronically within the time period prescribed. Examples of such 
events are acts of nature (e.g., hurricanes, earthquakes, or floods), 
acts of war or terrorism, or equipment failure or safety hazard beyond 
the control of the affected facility (e.g., large scale power outage).
    (B) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date you 
first knew, or through due diligence should have known, that the event 
may cause or has caused a delay in reporting.
    (C) The owner or operator must provide to the Administrator:
    (1) A written description of the force majeure event;
    (2) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (3) Measures taken or to be taken to minimize the delay in 
reporting; and
    (4) The date by which you propose to report, or if you have already 
met the reporting requirement at the time of the notification, the date 
you reported.
    (D) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (E) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.
* * * * *

[[Page 40439]]

    (d) * * *
    (1) Contents. The owner or operator shall submit a Notification of 
Compliance Status for each affected source subject to this subpart 
containing the information specified in paragraphs (d)(1)(i) and (ii) 
of this section. For pressure relief devices subject to the 
requirements of Sec.  63.1107(e)(3), the owner or operator of an 
acrylic and modacrylic fiber production affected source or 
polycarbonate production affected source shall also submit the 
information listed in paragraph (d)(1)(iii) of this section in a 
supplement to the Notification of Compliance Status within 150 days 
after the first applicable compliance date for pressure relief device 
monitoring. For flares subject to the requirements of Sec.  
63.1103(e)(4), the owner or operator of an ethylene production affected 
source shall also submit the information listed in paragraph (d)(1)(iv) 
of this section in a supplement to the Notification of Compliance 
Status within 150 days after the first applicable compliance date for 
flare monitoring. For pressure relief devices subject to the pressure 
release management work practice standards in Sec.  63.1107(h)(3), the 
owner or operator of an ethylene production affected source shall also 
submit the information listed in paragraph (d)(1)(v) of this section in 
a supplement to the Notification of Compliance Status within 150 days 
after the first applicable compliance date for pressure relief device 
monitoring.
    (i) Except as specified in paragraphs (d)(1)(iv) and (v) of this 
section, the Notification of Compliance Status shall include the 
information specified in this subpart and the subparts referenced by 
this subpart. Alternatively, this information can be submitted as part 
of a title V permit application or amendment.
* * * * *
    (iv) For each flare subject to the requirements in Sec.  
63.1103(e)(4), in lieu of the information required in Sec.  63.987(b) 
of subpart SS, the Notification of Compliance Status shall include 
flare design (e.g., steam-assisted, air-assisted, non-assisted, or 
pressure-assisted multi-point); all visible emission readings, heat 
content determinations, flow rate measurements, and exit velocity 
determinations made during the initial visible emissions demonstration 
required by Sec.  63.670(h) of subpart CC, as applicable; and all 
periods during the compliance determination when the pilot flame or 
flare flame is absent.
    (v) For pressure relief devices subject to the requirements of 
Sec.  63.1107(h), the Notification of Compliance Status shall include 
the information specified in paragraphs (d)(1)(v)(A) and (B) of this 
section.
    (A) A description of the monitoring system to be implemented, 
including the relief devices and process parameters to be monitored, 
and a description of the alarms or other methods by which operators 
will be notified of a pressure release.
    (B) A description of the prevention measures to be implemented for 
each affected pressure relief device.
* * * * *
    (e) * * *
    (1) Contents. Except as specified in paragraphs (e)(4) through (8) 
of this section, Periodic Reports shall include all information 
specified in this subpart and subparts referenced by this subpart.
* * * * *
    (4) Ethylene production flare reports. For each flare subject to 
the requirements in Sec.  63.1103(e)(4), the Periodic Report shall 
include the items specified in paragraphs (e)(4)(i) through (vi) of 
this section in lieu of the information required in Sec.  63.999(c)(3) 
of subpart SS.
    (i) Records as specified in Sec.  63.1109(e)(1) for each 15-minute 
block during which there was at least one minute when regulated 
material is routed to a flare and no pilot flame or flare flame is 
present. Include the start and stop time and date of each 15-minute 
block.
    (ii) Visible emission records as specified in Sec.  
63.1109(e)(2)(iv) for each period of 2 consecutive hours during which 
visible emissions exceeded a total of 5 minutes.
    (iii) The periods specified in Sec.  63.1109(e)(7). Indicate the 
date and start time for the period, and the net heating value operating 
parameter(s) determined following the methods in Sec.  63.670(k) 
through (n) of subpart CC as applicable.
    (iv) For flaring events meeting the criteria in Sec.  63.670(o)(3) 
of subpart CC and Sec.  63.1103(e)(4)(iv):
    (A) The start and stop time and date of the flaring event.
    (B) The length of time that emissions were visible from the flare 
during the event.
    (C) Results of the root cause and corrective actions analysis 
completed during the reporting period, including the corrective actions 
implemented during the reporting period and, if applicable, the 
implementation schedule for planned corrective actions to be 
implemented subsequent to the reporting period.
    (v) For pressure-assisted multi-point flares, the periods of time 
when the pressure monitor(s) on the main flare header show the burners 
operating outside the range of the manufacturer's specifications.
    (vi) For pressure-assisted multi-point flares, the periods of time 
when the staging valve position indicator monitoring system indicates a 
stage should not be in operation and is or when a stage should be in 
operation and is not.
    (5) Ethylene production maintenance vent reports. For maintenance 
vents subject to the requirements Sec.  63.1103(e)(5), Periodic Reports 
must include the information specified in paragraphs (e)(5)(i) through 
(iv) of this section for any release exceeding the applicable limits in 
Sec.  63.1103(e)(5)(i). For the purposes of this reporting requirement, 
owners or operators complying with Sec.  63.1103(e)(5)(i)(D) must 
report each venting event conducted under those provisions and include 
an explanation for each event as to why utilization of this alternative 
was required.
    (i) Identification of the maintenance vent and the equipment served 
by the maintenance vent.
    (ii) The date and time the maintenance vent was opened to the 
atmosphere.
    (iii) The LEL, vessel pressure, or mass of VOC in the equipment, as 
applicable, at the start of atmospheric venting. If the 5 psig vessel 
pressure option in Sec.  63.1103(e)(5)(i)(B) was used and active 
purging was initiated while the LEL was 10 percent or greater, also 
include the LEL of the vapors at the time active purging was initiated.
    (iv) An estimate of the mass of organic HAP released during the 
entire atmospheric venting event.
    (6) Bypass line reports. For bypass lines subject to the 
requirements in Sec.  63.1103(e)(6), Periodic Reports must include the 
date, time, duration, estimate of the volume of gas, the concentration 
of organic HAP in the gas and the resulting mass emissions of organic 
HAP that bypass a control device. For periods when the flow indicator 
is not operating, report the date, time, and duration.
    (7) Decoking operation reports. For decoking operations of an 
ethylene cracking furnace subject to the requirements in Sec.  
63.1103(e)(7) and (8), Periodic Reports must include the information 
specified in paragraphs (e)(7)(i) through (iii) of this section.
    (i) For each control measure selected to minimize coke combustion 
emissions as specified in Sec.  63.1103(e)(7)(ii) through (v), report 
instances where the control measures were not followed.

[[Page 40440]]

    (ii) Report instances where an isolation valve inspection was not 
conducted according to the procedures specified in Sec.  63.1103(e)(8).
    (iii) For instances where repair was delayed beyond 1 calendar day 
as specified in Sec.  63.1103(e)(7)(i), report the information 
specified in Sec.  63.1109(h)(1).
    (8) Ethylene production pressure relief devices reports. For 
pressure relief devices subject to the requirements of Sec.  
63.1107(h), Periodic Reports must include the information specified in 
paragraphs (e)(8)(i) through (iii) of this section.
    (i) For pressure relief devices in organic HAP gas or vapor 
service, pursuant to Sec.  63.1107(h)(1), report any instrument reading 
of 500 ppm or greater.
    (ii) For pressure relief devices in organic HAP gas or vapor 
service subject to Sec.  63.1107(h)(2), report confirmation that any 
monitoring required to be done during the reporting period to show 
compliance was conducted.
    (iii) For pressure relief devices in organic HAP service subject to 
Sec.  63.1107(h)(3), report each pressure release to the atmosphere, 
including duration of the pressure release and estimate of the mass 
quantity of each organic HAP released; the results of any root cause 
analysis and corrective action analysis completed during the reporting 
period, including the corrective actions implemented during the 
reporting period; and, if applicable, the implementation schedule for 
planned corrective actions to be implemented subsequent to the 
reporting period.
* * * * *
    (g) * * *
    (1) Submission to the Environmental Protection Agency. All reports 
and notifications required under this subpart shall be sent to the 
appropriate EPA Regional Office and to the delegated State authority, 
except that request for permission to use an alternative means of 
emission limitation as provided for in Sec.  63.1113 shall be submitted 
to the Director of the EPA Office of Air Quality Planning and 
Standards, U.S. Environmental Protection Agency, MD-10, Research 
Triangle Park, North Carolina, 27711. The EPA Regional Office may waive 
the requirement to submit a copy of any reports or notifications at its 
discretion, except that electronic reporting to CEDRI cannot be waived, 
and as such, compliance with the provisions of this paragraph does not 
relieve owners or operators of affected facilities of the requirement 
to submit electronic reports required in this subpart to the EPA.
    (2) Submission of copies. If any State requires a notice that 
contains all the information required in a report or notification 
listed in this subpart, an owner or operator may send the appropriate 
EPA Regional Office a copy of the report or notification sent to the 
State to satisfy the requirements of this subpart for that report or 
notification, except that performance test reports and performance 
evaluation reports required under paragraph (a)(10) of this section 
must be submitted to CEDRI in the format specified in that paragraph.
* * * * *

0
26. Section 63.1111 is amended by revising paragraphs (a) introductory 
text, (b) introductory text, and (c) introductory text to read as 
follows:


Sec.  63.1111   Startup, shutdown, and malfunction.

    (a) Startup, shutdown, and malfunction plan. Before July 6, 2023, 
the requirements of this paragraph (a) apply to all affected sources 
except for acrylic and modacrylic fiber production affected sources and 
polycarbonate production affected sources. On and after July 6, 2023, 
the requirements of this paragraph (a) apply to all affected sources 
except for acrylic and modacrylic fiber production affected sources, 
ethylene production affected sources, and polycarbonate production 
affected sources.
* * * * *
    (b) Startup, shutdown, and malfunction reporting requirements. 
Before July 6, 2023, the requirements of this paragraph (b) apply to 
all affected sources except for acrylic and modacrylic fiber production 
affected sources and polycarbonate production affected sources. On and 
after July 6, 2023, the requirements of this paragraph (b) apply to all 
affected sources except for acrylic and modacrylic fiber production 
affected sources, ethylene production affected sources, and 
polycarbonate production affected sources.
* * * * *
    (c) Malfunction recordkeeping and reporting. Before July 6, 2023, 
the requirements of this paragraph (c) apply only to acrylic and 
modacrylic fiber production affected sources and polycarbonate 
production affected sources. On and after July 6, 2023, the 
requirements of this paragraph (c) apply only to acrylic and modacrylic 
fiber production affected sources, ethylene production affected 
sources, and polycarbonate production affected sources.
* * * * *

0
27. Section 63.1112 is amended by revising paragraph (d)(2) to read as 
follows:


Sec.  63.1112   Extension of compliance, and performance test, 
monitoring, recordkeeping and reporting waivers and alternatives.

* * * * *
    (d) * * *
    (2) Recordkeeping or reporting requirements may be waived upon 
written application to the Administrator if, in the Administrator's 
judgment, the affected source is achieving the relevant standard(s), or 
the source is operating under an extension of compliance, or the owner 
or operator has requested an extension of compliance and the 
Administrator is still considering that request. Electronic reporting 
to the EPA cannot be waived, and as such, compliance with the 
provisions of this paragraph does not relieve owners or operators of 
affected facilities of the requirement to submit electronic reports 
required in this subpart to the EPA.
* * * * *

0
28. Section 63.1113 is amended by revising paragraph (a)(2) to read as 
follows:


Sec.  63.1113   Procedures for approval of alternative means of 
emission limitation.

    (a) * * *
    (2) Any such notice shall be published only after public notice and 
an opportunity for public comment.
* * * * *

0
29. Section 63.1114 is amended by revising paragraph (b) introductory 
text and adding paragraph (b)(6) to read as follows:


Sec.  63.1114   Implementation and enforcement.

* * * * *
    (b) In delegating implementation and enforcement authority of this 
subpart to a state, local, or tribal agency under subpart E to this 
part, the authorities contained in paragraphs (b)(1) through (6) of 
this section are retained by the EPA Administrator and are not 
transferred to the State, local, or tribal agency.
* * * * *
    (6) Approval of an alternative to any electronic reporting to EPA 
required by this subpart.

[FR Doc. 2020-05898 Filed 7-2-20; 8:45 am]
BILLING CODE 6560-50-P