National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Residual Risk and Technology Review, 44254-44285 [2017-19448]
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Federal Register / Vol. 82, No. 182 / Thursday, September 21, 2017 / Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 63
[EPA–HQ–OAR–2016–0442; FRL–9967–61–
OAR]
RIN 2060–AS92
National Emission Standards for
Hazardous Air Pollutants From the
Portland Cement Manufacturing
Industry Residual Risk and
Technology Review
Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
AGENCY:
The Environmental Protection
Agency (EPA) is proposing amendments
to the National Emission Standards for
Hazardous Air Pollutants (NESHAP)
From the Portland Cement
Manufacturing Industry to address the
results of the residual risk and
technology review (RTR) the EPA is
required to conduct in accordance with
section 112 of the Clean Air Act (CAA).
We found risks due to emissions of air
toxics to be acceptable from this source
category with an ample margin of safety,
and we identified no new cost-effective
controls under the technology review to
achieve further emissions reductions.
Therefore, we are proposing no
revisions to the numerical emission
limits based on these analyses.
However, the EPA is proposing
amendments to correct and clarify rule
requirements and provisions. While the
proposed amendments would not result
in reductions in emissions of hazardous
air pollutants (HAP), this action, if
finalized, would result in improved
monitoring, compliance, and
implementation of the rule.
DATES:
Comments. Comments must be
received on or before November 6, 2017.
Public Hearing. If a public hearing is
requested by September 26, 2017, the
EPA will hold a public hearing on
October 6, 2017. The last day to preregister in advance to speak at the
public hearing will be October 4, 2017.
ADDRESSES: Comments. Submit your
comments, identified by Docket ID No.
EPA–HQ–OAR–2016–0442, at https://
www.regulations.gov. Follow the online
instructions for submitting comments.
Once submitted, comments cannot be
edited or removed from Regulations.gov.
The EPA may publish any comment
received to its public docket. Do not
submit electronically any information
you consider to be Confidential
Business Information (CBI) or other
information whose disclosure is
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restricted by statute. Multimedia
submissions (audio, video, etc.) must be
accompanied by a written comment.
The written comment is considered the
official comment and should include
discussion of all points you wish to
make. The EPA will generally not
consider comments or comment
contents located outside of the primary
submission (i.e., on the Web, cloud, or
other file sharing system). For
additional submission methods, the full
EPA public comment policy,
information about CBI or multimedia
submissions, and general guidance on
making effective comments, please visit
https://www2.epa.gov/dockets/
commenting-epa-dockets.
Public Hearing. If a hearing is
requested, it will be held at the EPA
WJC East Building, 1201 Constitution
Avenue NW., Washington, DC 20004. If
a public hearing is requested, then we
will provide details about the public
hearing on our Web site at https://
www.epa.gov/stationary-sources-airpollution/portland-cementmanufacturing-industry-nationalemission-standards. The EPA does not
intend to publish any future notices in
the Federal Register announcing any
updates on the request for public
hearing. Please contact Aimee St. Clair
at (919) 541–1063 or by email at
stclair.aimee@epa.gov to request a
public hearing, to register to speak at the
public hearing, or to inquire as to
whether a public hearing will be held.
For
questions about this proposed action,
contact Mr. Brian Storey, Sector Policies
and Programs Division (D243–04),
Office of Air Quality Planning and
Standards, U.S. Environmental
Protection Agency, Research Triangle
Park, North Carolina 27711; telephone
number: (919) 541–1103; fax number:
(919) 541–5450; and email address:
storey.brian@epa.gov. For specific
information regarding the risk modeling
methodology, contact Mr. James Hirtz,
Health and Environmental Impacts
Division (C539–02), Office of Air
Quality Planning and Standards, U.S.
Environmental Protection Agency,
Research Triangle Park, North Carolina
27711; telephone number: (919) 541–
0881; fax number: (919) 541–0840; and
email address: hirtz.james@epa.gov. For
information about the applicability of
the NESHAP to a particular entity,
contact Ms. Sara Ayres, Office of
Enforcement and Compliance
Assurance, U.S. Environmental
Protection Agency, U.S. EPA Region 5
(E–19J), 77 West Jackson Boulevard,
Chicago, IL 60604; telephone number:
FOR FURTHER INFORMATION CONTACT:
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(312) 353–6266; email address:
ayres.sara@epa.gov.
SUPPLEMENTARY INFORMATION:
Docket. The EPA has established a
docket for this rulemaking under Docket
ID No. EPA–HQ–OAR–2016–0442. All
documents in the docket are listed in
the Regulations.gov index. Although
listed in the index, some information is
not publicly available, e.g., CBI or other
information whose disclosure is
restricted by statute. Certain other
material, such as copyrighted material,
is not placed on the Internet and will be
publicly available only in hard copy.
Publicly available docket materials are
available either electronically in
Regulations.gov or in hard copy at the
EPA Docket Center, Room 3334, EPA
WJC West Building, 1301 Constitution
Avenue NW., Washington, DC. The
Public Reading Room is open from 8:30
a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The
telephone number for the Public
Reading Room is (202) 566–1744, and
the telephone number for the EPA
Docket Center is (202) 566–1742.
Instructions. Direct your comments to
Docket ID No. EPA–HQ–OAR–2016–
0442. The EPA’s policy is that all
comments received will be included in
the public docket without change and
may be made available online at https://
www.regulations.gov, including any
personal information provided, unless
the comment includes information
claimed to be CBI or other information
whose disclosure is restricted by statute.
Do not submit information that you
consider to be CBI or otherwise
protected through https://
www.regulations.gov or email. The
https://www.regulations.gov Web site is
an ‘‘anonymous access’’ system, which
means the EPA will not know your
identity or contact information unless
you provide it in the body of your
comment. If you send an email
comment directly to the EPA without
going through https://
www.regulations.gov, your email
address will be automatically captured
and included as part of the comment
that is placed in the public docket and
made available on the Internet. If you
submit an electronic comment, the EPA
recommends that you include your
name and other contact information in
the body of your comment and with any
disk or CD–ROM you submit. If the EPA
cannot read your comment due to
technical difficulties and cannot contact
you for clarification, the EPA may not
be able to consider your comment.
Electronic files should not include
special characters or any form of
encryption and be free of any defects or
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viruses. For additional information
about the EPA’s public docket, visit the
EPA Docket Center homepage at https://
www.epa.gov/dockets.
Preamble Acronyms and
Abbreviations. We use multiple
acronyms and terms in this preamble.
While this list may not be exhaustive, to
ease the reading of this preamble and for
reference purposes, the EPA defines the
following terms and acronyms here:
ACI activated carbon injection
AEGL acute exposure guideline levels
AERMOD air dispersion model used by the
HEM–3 model
CAA Clean Air Act
CalEPA California EPA
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data
Reporting Interface
CFR Code of Federal Regulations
CISWI commercial and industrial solid
waste incinerators
CO carbon monoxide
D/F dioxins and furans
EPA Environmental Protection Agency
ERP Emergency Response Planning
ERPG Emergency Response Planning
Guidelines
ERT Electronic Reporting Tool
ESP electrostatic precipitators
FR Federal Register
GHGRP Greenhouse Gas Reporting Program
HAP hazardous air pollutants
HCl hydrochloric acid
HEM–3 Human Exposure Model
HF hydrogen fluoride
HI hazard index
HQ hazard quotient
IRIS Integrated Risk Information System
km kilometer
lb/hr pounds per hour
lb/ton pounds per ton
LOAEL lowest-observed-adverse-effect level
MACT maximum achievable control
technology
mg/kg-day milligrams per kilogram per day
mg/m3 milligrams per cubic meter
mg/Nm3 milligrams per normal cubic meter
MIR maximum individual risk
NAAQS National Ambient Air Quality
Standards
NAC National Advisory Committee
NAICS North American Industry
Classification System
NAS National Academy of Sciences
NATA National Air Toxics Assessment
NEI National Emissions Inventory
NESHAP national emission standards for
hazardous air pollutants
NOX nitrogen oxides
NOAA National Oceanic and Atmospheric
Administration
NOAEL no-observed-adverse-effect level
NRC National Research Council
NRDC Natural Resources Defense Council
NSPS new source performance standards
NTTAA National Technology Transfer and
Advancement Act
OAQPS Office of Air Quality Planning and
Standards
OMB Office of Management and Budget
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PB–HAP hazardous air pollutants known to
be persistent and bio-accumulative in the
environment
PCA Portland Cement Association
PEL probable effect level
PM particulate matter
POM polycyclic organic matter
ppm parts per million
ppmvd parts per million by volume, dry
basis
PRA Paperwork Reduction Act
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RfD reference dose
RTO regenerative thermal oxidizers
RTR residual risk and technology review
SAB Science Advisory Board
SCR selective catalytic reduction
SO2 sulfur dioxide
TEF toxicity equivalence factors
TEQ toxic equivalents
THC total hydrocarbons
TOSHI target organ-specific hazard index
tpy tons per year
TRIM.FaTE Total Risk Integrated
Methodology.Fate, Transport, and
Ecological Exposure model
UF uncertainty factor
mg/m3 microgram per cubic meter
UISIS Universal Industrial Sectors
Integrated Solutions
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
U.S.C. United States Code
WebFIRE Web Factor Information Retrieval
System
Organization of this Document. The
information in this preamble is
organized as follows:
I. General Information
A. Does this action apply to me?
B. Where can I get a copy of this document
and other related information?
C. What should I consider as I prepare my
comments for the EPA?
II. Background
A. What is the statutory authority for this
action?
B. What is this source category and how
does the current NESHAP regulate its
HAP emissions?
C. What data collection activities were
conducted to support this action?
D. What other relevant background
information and data are available?
III. Analytical Procedures
A. How did we estimate post-MACT risks
posed by the source category?
B. How did we consider the risk results in
making decisions for this proposal?
C. How did we perform the technology
review?
IV. Analytical Results and Proposed
Decisions
A. What are the results of the risk
assessment and analyses?
B. What are our proposed decisions
regarding risk acceptability, ample
margin of safety, and adverse
environmental effects?
C. What are the results and proposed
decisions based on our technology
review?
D. What other actions are we proposing?
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E. What compliance dates are we
proposing?
V. Summary of Cost, Environmental, and
Economic Impacts
A. What are the impacts to affected
sources?
B. What are the air quality impacts?
C. What are the cost impacts?
D. What are the economic impacts?
E. What are the benefits?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. Statutory and Executive Order Reviews
A. Executive Order 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)
K. Executive Order 12898: Federal Actions
To Address Environmental Justice in
Minority Populations and Low-Income
Populations
I. General Information
A. Does this action apply to me?
Table 1 of this preamble lists the
NESHAP and associated regulated
industrial source category that is the
subject of this proposal. Table 1 is not
intended to be exhaustive, but rather
provides a guide for readers regarding
the entities that this proposed action is
likely to affect. The proposed standards,
once promulgated, will be directly
applicable to the affected sources.
Federal, state, local, and tribal
government entities would not be
affected by this proposed action. As
defined in the Initial List of Categories
of Sources Under Section 112(c)(1) of
the Clean Air Act Amendments of 1990
(see 57 FR 31576, July 16, 1992), the
Portland Cement Manufacturing
Industry source category is any facility
engaged in manufacturing Portland
cement by either the wet or dry process.
The category includes, but is not limited
to, the following process units: Kiln,
clinker cooler, raw mill system, finish
mill system, raw mill dryer, raw
material storage, clinker storage,
finished product storage, conveyor
transfer points, bagging, and bulk
loading and unloading systems.
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TABLE 1—NESHAP AND INDUSTRIAL SOURCE CATEGORIES AFFECTED BY THIS PROPOSED ACTION
Source category
NESHAP
NAICS code 1
Portland cement manufacturing facilities .................................
40 CFR part 63 subpart LLL ...................................................
327310
1 North
American Industry Classification System.
The source category does not include
those kilns that burn hazardous waste
and are subject to and regulated under
40 CFR part 63, subpart EEE, or kilns
that burn solid waste and are subject to
the Commercial and Industrial Solid
Waste Incinerator (CISWI) rule under 40
CFR part 60, subparts CCCC and DDDD.
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B. Where can I get a copy of this
document and other related
information?
In addition to being available in the
docket, an electronic copy of this action
is available on the Internet. Following
signature by the EPA Administrator, the
EPA will post a copy of this proposed
action at https://www3.epa.gov/
airquality/cement/actions.html.
Following publication in the Federal
Register, the EPA will post the Federal
Register version of the proposal and key
technical documents at this same Web
site. Information on the overall RTR
program is available at https://
www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
C. What should I consider as I prepare
my comments for the EPA?
Submitting CBI. Do not submit
information containing CBI to the EPA
through https://www.regulations.gov or
email. Clearly mark the part or all of the
information that you claim to be CBI.
For CBI information on a disk or CD–
ROM that you mail to the EPA, mark the
outside of the disk or CD–ROM as CBI
and then identify electronically within
the disk or CD–ROM the specific
information that is claimed as CBI. In
addition to one complete version of the
comments that includes information
claimed as CBI, you must submit a copy
of the comments that does not contain
the information claimed as CBI for
inclusion in the public docket. If you
submit a CD–ROM or disk that does not
contain CBI, mark the outside of the
disk or CD–ROM clearly that it does not
contain CBI. Information not marked as
CBI will be included in the public
docket and the EPA’s electronic public
docket without prior notice. Information
marked as CBI will not be disclosed
except in accordance with procedures
set forth in 40 Code of Federal
Regulations (CFR) part 2. Send or
deliver information identified as CBI
only to the following address: OAQPS
Document Control Officer (C404–02),
OAQPS, U.S. Environmental Protection
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Agency, Research Triangle Park, North
Carolina 27711, Attention Docket ID No.
EPA–HQ–OAR–2016–0442.
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, after the EPA
has identified categories of sources
emitting one or more of the HAP listed
in CAA section 112(b), CAA section
112(d) requires us to promulgate
technology-based NESHAP for those
sources. ‘‘Major sources’’ are those that
emit or have the potential to emit 10
tons per year (tpy) or more of a single
HAP or 25 tpy or more of any
combination of HAP. For major sources,
the technology-based NESHAP must
reflect the maximum degree of emission
reductions of HAP achievable (after
considering cost, energy requirements,
and non-air quality health and
environmental impacts) and are
commonly referred to as maximum
achievable control technology (MACT)
standards.
MACT standards must reflect the
maximum degree of emissions reduction
achievable through the application of
measures, processes, methods, systems,
or techniques, including, but not limited
to, measures that: (1) Reduce the volume
of or eliminate pollutants through
process changes, substitution of
materials, or other modifications; (2)
enclose systems or processes to
eliminate emissions; (3) capture or treat
pollutants when released from a
process, stack, storage, or fugitive
emissions point; (4) are design,
equipment, work practice, or
operational standards (including
requirements for operator training or
certification); or (5) are a combination of
the above. CAA section 112(d)(2)(A)–
(E). The MACT standards may take the
form of design, equipment, work
practice, or operational standards where
the EPA first determines either that: (1)
A pollutant cannot be emitted through
a conveyance designed and constructed
to emit or capture the pollutant, or that
any requirement for, or use of, such a
conveyance would be inconsistent with
law; or (2) the application of
measurement methodology to a
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particular class of sources is not
practicable due to technological and
economic limitations. CAA section
112(h)(1)–(2).
The MACT ‘‘floor’’ is the minimum
control level allowed for MACT
standards promulgated under CAA
section 112(d)(3) and may not be based
on cost considerations. For new sources,
the MACT floor cannot be less stringent
than the emissions control that is
achieved in practice by the bestcontrolled similar source. The MACT
floor for existing sources can be less
stringent than floors for new sources,
but not less stringent than the average
emissions limitation achieved by the
best-performing 12 percent of existing
sources in the category or subcategory
(or the best-performing five sources for
categories or subcategories with fewer
than 30 sources). In developing MACT
standards, the EPA must also consider
control options that are more stringent
than the floor. We may establish
standards more stringent than the floor
based on considerations of the cost of
achieving the emission reductions, any
non-air quality health and
environmental impacts, and energy
requirements.
The EPA is then required to review
these technology-based standards and
revise them ‘‘as necessary (taking into
account developments in practices,
processes, and control technologies)’’ no
less frequently than every 8 years. CAA
section 112(d)(6). In conducting this
review, the EPA is not required to
recalculate the MACT floor. Natural
Resources Defense Council (NRDC) v.
EPA, 529 F.3d 1077, 1084 (D.C. Cir.
2008). Association of Battery Recyclers,
Inc. v. EPA, 716 F.3d 667 (D.C. Cir.
2013).
The second stage in standard-setting
focuses on reducing any remaining (i.e.,
‘‘residual’’) risk according to CAA
section 112(f). Section 112(f)(1) of the
CAA required that the EPA prepare a
report to Congress discussing (among
other things) methods of calculating the
risks posed (or potentially posed) by
sources after implementation of the
MACT standards, the public health
significance of those risks, and the
EPA’s recommendations as to legislation
regarding such remaining risk. The EPA
prepared and submitted the Residual
Risk Report to Congress, EPA–453/R–
99–001 (Risk Report) in March 1999.
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Section 112(f)(2) of the CAA then
provides that if Congress does not act on
any recommendation in the Risk Report,
the EPA must analyze and address
residual risk for each category or
subcategory of sources 8 years after
promulgation of such standards
pursuant to CAA section 112(d).
Section 112(f)(2) of the CAA requires
the EPA to determine for source
categories subject to MACT standards
whether promulgation of additional
standards is needed to provide an ample
margin of safety to protect public health.
Section 112(f)(2)(B) of the CAA
expressly preserves the EPA’s use of the
two-step process for developing
standards to address any residual risk
and the Agency’s interpretation of
‘‘ample margin of safety’’ developed in
the National Emissions Standards for
Hazardous Air Pollutants: Benzene
Emissions from Maleic Anhydride
Plants, Ethylbenzene/Styrene Plants,
Benzene Storage Vessels, Benzene
Equipment Leaks, and Coke By-Product
Recovery Plants (Benzene NESHAP) (54
FR 38044, September 14, 1989). The
EPA notified Congress in the Risk
Report that the Agency intended to use
the Benzene NESHAP approach in
making CAA section 112(f) residual risk
determinations (EPA–453/R–99–001, p.
ES–11). The EPA subsequently adopted
this approach in its residual risk
determinations and in a challenge to the
risk review for the Synthetic Organic
Chemical Manufacturing source
category, the United States Court of
Appeals for the District of Columbia
Circuit (the Court) upheld as reasonable
the EPA’s interpretation that CAA
section 112(f)(2) incorporates the
approach established in the Benzene
NESHAP. See NRDC v. EPA, 529 F.3d
1077, 1083 (D.C. Cir. 2008)
(‘‘[S]ubsection 112(f)(2)(B) expressly
incorporates the EPA’s interpretation of
the Clean Air Act from the Benzene
standard, complete with a citation to the
Federal Register.’’); see also, A
Legislative History of the Clean Air Act
Amendments of 1990, vol. 1, p. 877
(Senate debate on Conference Report).
The first step in the process of
evaluating residual risk is the
determination of acceptable risk. If risks
are unacceptable, the EPA cannot
consider cost in identifying the
emissions standards necessary to bring
risks to an acceptable level. The second
step is the determination of whether
standards must be further revised in
order to provide an ample margin of
safety to protect public health. The
ample margin of safety is the level at
which the standards must be set, unless
an even more stringent standard is
necessary to prevent, taking into
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consideration costs, energy, safety, and
other relevant factors, an adverse
environmental effect.
1. Step 1—Determination of
Acceptability
The Agency in the Benzene NESHAP
concluded that ‘‘the acceptability of risk
under section 112 is best judged on the
basis of a broad set of health risk
measures and information’’ and that the
‘‘judgment on acceptability cannot be
reduced to any single factor.’’ Benzene
NESHAP at 38046. The determination of
what represents an ‘‘acceptable’’ risk is
based on a judgment of ‘‘what risks are
acceptable in the world in which we
live’’ (Risk Report at 178, quoting NRDC
v. EPA, 824 F. 2d 1146, 1165 (D.C. Cir.
1987) (en banc) (‘‘Vinyl Chloride’’),
recognizing that our world is not riskfree.
In the Benzene NESHAP, we stated
that ‘‘EPA will generally presume that if
the risk to [the maximum exposed]
individual is no higher than
approximately one in 10 thousand, that
risk level is considered acceptable.’’ 54
FR at 38045, September 14, 1989. We
discussed the maximum individual
lifetime cancer risk (or maximum
individual risk (MIR)) as being ‘‘the
estimated risk that a person living near
a plant would have if he or she were
exposed to the maximum pollutant
concentrations for 70 years.’’ Id. We
explained that this measure of risk ‘‘is
an estimate of the upper bound of risk
based on conservative assumptions,
such as continuous exposure for 24
hours per day for 70 years.’’ Id. We
acknowledged that maximum
individual lifetime cancer risk ‘‘does not
necessarily reflect the true risk, but
displays a conservative risk level which
is an upper-bound that is unlikely to be
exceeded.’’ Id.
Understanding that there are both
benefits and limitations to using the
MIR as a metric for determining
acceptability, we acknowledged in the
Benzene NESHAP that ‘‘consideration of
maximum individual risk * * * must
take into account the strengths and
weaknesses of this measure of risk.’’ Id.
Consequently, the presumptive risk
level of 100-in-1 million (1-in-10
thousand) provides a benchmark for
judging the acceptability of maximum
individual lifetime cancer risk, but does
not constitute a rigid line for making
that determination. Further, in the
Benzene NESHAP, we noted that:
[p]articular attention will also be accorded to
the weight of evidence presented in the risk
assessment of potential carcinogenicity or
other health effects of a pollutant. While the
same numerical risk may be estimated for an
exposure to a pollutant judged to be a known
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human carcinogen, and to a pollutant
considered a possible human carcinogen
based on limited animal test data, the same
weight cannot be accorded to both estimates.
In considering the potential public health
effects of the two pollutants, the Agency’s
judgment on acceptability, including the
MIR, will be influenced by the greater weight
of evidence for the known human
carcinogen.
Id. at 38046. The Agency also explained
in the Benzene NESHAP that:
[i]n establishing a presumption for MIR,
rather than a rigid line for acceptability, the
Agency intends to weigh it with a series of
other health measures and factors. These
include the overall incidence of cancer or
other serious health effects within the
exposed population, the numbers of persons
exposed within each individual lifetime risk
range and associated incidence within,
typically, a 50 km exposure radius around
facilities, the science policy assumptions and
estimation uncertainties associated with the
risk measures, weight of the scientific
evidence for human health effects, other
quantified or unquantified health effects,
effects due to co-location of facilities, and coemission of pollutants.
Id. at 38045. In some cases, these health
measures and factors taken together may
provide a more realistic description of
the magnitude of risk in the exposed
population than that provided by
maximum individual lifetime cancer
risk alone.
As noted earlier, in NRDC v. EPA, the
Court held that CAA section 112(f)(2)
‘‘incorporates the EPA’s interpretation
of the Clean Air Act from the Benzene
Standard.’’ The Court further held that
Congress’ incorporation of the Benzene
standard applies equally to carcinogens
and non-carcinogens. 529 F.3d at 1081–
82. Accordingly, we also consider noncancer risk metrics in our determination
of risk acceptability and ample margin
of safety.
2. Step 2—Determination of Ample
Margin of Safety
Section 112(f)(2) of the CAA requires
the EPA to determine, for source
categories subject to MACT standards,
whether those standards provide an
ample margin of safety to protect public
health. As explained in the Benzene
NESHAP, ‘‘the second step of the
inquiry, determining an ‘ample margin
of safety,’ again includes consideration
of all of the health factors, and whether
to reduce the risks even further * * *.
Beyond that information, additional
factors relating to the appropriate level
of control will also be considered,
including costs and economic impacts
of controls, technological feasibility,
uncertainties, and any other relevant
factors. Considering all of these factors,
the agency will establish the standard at
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a level that provides an ample margin of
safety to protect the public health, as
required by section 112.’’ 54 FR 38046,
September 14, 1989.
According to CAA section
112(f)(2)(A), if the MACT standards for
HAP ‘‘classified as a known, probable,
or possible human carcinogen do not
reduce lifetime excess cancer risks to
the individual most exposed to
emissions from a source in the category
or subcategory to less than one in one
million,’’ the EPA must promulgate
residual risk standards for the source
category (or subcategory), as necessary
to provide an ample margin of safety to
protect public health. In doing so, the
EPA may adopt standards equal to
existing MACT standards if the EPA
determines that the existing standards
(i.e., the MACT standards) are
sufficiently protective. NRDC v. EPA,
529 F.3d 1077, 1083 (D.C. Cir. 2008) (‘‘If
EPA determines that the existing
technology-based standards provide an
’ample margin of safety,’ then the
Agency is free to readopt those
standards during the residual risk
rulemaking.’’) The EPA must also adopt
more stringent standards, if necessary,
to prevent an adverse environmental
effect,1 but must consider cost, energy,
safety, and other relevant factors in
doing so.
The CAA does not specifically define
the terms ‘‘individual most exposed,’’
‘‘acceptable level,’’ and ‘‘ample margin
of safety.’’ In the Benzene NESHAP, 54
FR at 38044–38045, September 14, 1989,
we stated as an overall objective:
In protecting public health with an ample
margin of safety under section 112, EPA
strives to provide maximum feasible
protection against risks to health from
hazardous air pollutants by (1) protecting the
greatest number of persons possible to an
individual lifetime risk level no higher than
approximately 1-in-1 million and (2) limiting
to no higher than approximately 1-in-10
thousand [i.e., 100-in-1 million] the
estimated risk that a person living near a
plant would have if he or she were exposed
to the maximum pollutant concentrations for
70 years.
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The Agency further stated that ‘‘[t]he
EPA also considers incidence (the
number of persons estimated to suffer
cancer or other serious health effects as
a result of exposure to a pollutant) to be
an important measure of the health risk
to the exposed population. Incidence
measures the extent of health risks to
the exposed population as a whole, by
providing an estimate of the occurrence
of cancer or other serious health effects
in the exposed population.’’ Id. at
38045.
In the ample margin of safety decision
process, the Agency again considers all
of the health risks and other health
information considered in the first step,
including the incremental risk reduction
associated with standards more
stringent than the MACT standard or a
more stringent standard that the EPA
has determined is necessary to ensure
risk is acceptable. In the ample margin
of safety analysis, the Agency considers
additional factors, including costs and
economic impacts of controls,
technological feasibility, uncertainties,
and any other relevant factors.
Considering all of these factors, the
Agency will establish the standard at a
level that provides an ample margin of
safety to protect the public health, as
required by CAA section 112(f). 54 FR
38046, September 14, 1989.
B. What is this source category and how
does the current NESHAP regulate its
HAP emissions?
The EPA initially promulgated the
Portland Cement Manufacturing
Industry NESHAP on June 14, 1999 (64
FR 31898), under title 40, part 63,
subpart LLL of the CFR (40 CFR part 63,
subpart LLL). The rule was amended on
April 5, 2002 (67 FR 16614); July 5,
2002 (67 FR 44766); December 6, 2002
(67 FR 72580); December 20, 2006 (71
FR 76518); September 9, 2010 (75 FR
54970); January 18, 2011 (76 FR 2832);
February 12, 2013 (78 FR 10006); July
27, 2015 (80 FR 44772); September 11,
2015 (80 FR 54728); and July 25, 2016
(81 FR 48356). The amendments further
defined affected cement kilns as those
used to manufacture Portland cement,
except for kilns that burn hazardous
waste, and are subject to and regulated
under 40 CFR part 63, subpart EEE, and
kilns that burn solid waste, which are
subject to the CISWI rule under 40 CFR
part 60, subparts CCCC and DDDD.
Additionally, onsite sources that are
subject to standards for nonmetallic
mineral processing plants in 40 CFR
part 60, subpart OOO are not subject to
40 CFR part 63, subpart LLL. Crushers
are not covered by 40 CFR part 63,
subpart LLL regardless of their location.
Subpart LLL NESHAP regulates HAP
emissions from new and existing
Portland cement production facilities
that are major or area sources of HAP,
with one exception. Kilns located at
facilities that are area sources, are not
regulated for hydrochloric acid (HCl)
emissions.
Portland cement manufacturing is an
energy-intensive process in which
cement is made by grinding and heating
a mixture of raw materials such as
limestone, clay, sand, and iron ore in a
rotary kiln. The kiln is a large furnace
that is fueled by coal, oil, gas, coke, and/
or various waste materials. The product
(known as clinker) from the kiln is
cooled, ground, and then mixed with a
small amount of gypsum to produce
Portland cement.
The main source of air toxics
emissions from a Portland cement plant
is the kiln. Emissions originate from the
burning of fuels and heating of feed
materials. Air toxics are also emitted
from the grinding, cooling, and
materials handling steps in the
manufacturing process. Pollutants
regulated under the subpart LLL
NESHAP are particulate matter (PM) as
a surrogate for non-mercury HAP
metals, total hydrocarbons (THC) as a
surrogate for organic HAP other than
dioxins and furans (D/F), organic HAP
as an alternative to the limit for THC,
mercury, HCl (from major sources only),
and D/F expressed as toxic equivalents
(TEQ). The kiln is regulated for all HAP
and raw material dryers are regulated
for THC or the alternative organic HAP.
Clinker coolers are regulated for PM.
Finish mills and raw mills are regulated
for opacity. During periods of startup
and shutdown, the kiln, clinker cooler,
and raw material dryer are regulated by
work practices. Open clinker storage
piles are regulated by work practices.
The emission standards for the affected
sources are summarized in Table 2.
TABLE 2—EMISSION LIMITS FOR KILNS, CLINKER COOLERS, RAW MATERIAL DRYERS, RAW AND FINISH MILLS
If your source is a (an):
And the operating mode is:
And it is located at a:
Your emissions limits are:
And the units of the
emissions limit are:
The oxygen
correction
factor is:
1. Existing kiln ......................
Normal operation ................
Major or area source ..........
PM 1 0.07 ............................
Pounds (lb)/ton clinker ........
NA.
1 ‘‘Adverse environmental effect’’ is defined as
any significant and widespread adverse effect,
which may be reasonably anticipated to wildlife,
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aquatic life, or natural resources, including adverse
impacts on populations of endangered or threatened
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species or significant degradation of environmental
qualities over broad areas. CAA section 112(a)(7).
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TABLE 2—EMISSION LIMITS FOR KILNS, CLINKER COOLERS, RAW MATERIAL DRYERS, RAW AND FINISH MILLS—Continued
And the operating mode is:
Your emissions limits are:
And it is located at a:
And the units of the
emissions limit are:
The oxygen
correction
factor is:
D/F 2 0.2 ..............................
If your source is a (an):
Nanograms/dry standard
cubic meters (ng/dscm)
(TEQ).
lb/million (MM) tons clinker
Parts per million, volumetric
dry (ppmvd).
ppmvd .................................
NA .......................................
7 percent.
7 percent.
NA.
lb/ton clinker .......................
ng/dscm (TEQ) ...................
lb/MM tons clinker ..............
ppmvd .................................
ppmvd .................................
NA .......................................
NA.
7 percent.
NA.
7 percent.
7 percent.
NA.
lb/ton clinker .......................
NA .......................................
NA.
NA.
lb/ton clinker .......................
NA .......................................
NA.
NA.
ppmvd .................................
NA.
NA .......................................
NA.
percent ................................
NA.
Mercury 55 ..........................
THC 3 4 24 ...........................
2. Existing kiln ......................
3. Existing kiln ......................
Normal operation ................
Startup and shutdown ........
Major source .......................
Major or area source ..........
4. New kiln ...........................
Normal operation ................
Major or area source ..........
5. New kiln ...........................
6. New kiln ...........................
Normal operation ................
Startup and shutdown ........
Major source .......................
Major or area source ..........
7. Existing clinker cooler ......
8. Existing clinker cooler ......
Normal operation ................
Startup and shutdown ........
Major or area source ..........
Major or area source ..........
9. New clinker cooler ...........
10. New clinker cooler .........
Normal operation ................
Startup and shutdown ........
Major or area source ..........
Major or area source ..........
11. Existing or new raw material dryer.
12. Existing or new raw material dryer.
13. Existing or new raw or
finish mill.
Normal operation ................
Major or area source ..........
Startup and shutdown ........
Major or area source ..........
All operating modes ............
Major source .......................
HCl 3 ...................................
Work practices ....................
(63.1346(g)) ........................
PM 1 0.02 ............................
D/F 2 0.2 ..............................
Mercury 21 ..........................
THC 3 4 24 ...........................
HCl 3 ...................................
Work practices ....................
(63.1346(g)) ........................
PM 0.07 ..............................
Work practices
(63.1348(b)(9)).
PM 0.02 ..............................
Work practices
(63.1348(b)(9)).
THC 3 4 24 ...........................
Work practices
(63.1348(b)(9)).
Opacity 10 ..........................
NA.
7 percent.
1 The
initial and subsequent PM performance tests are performed using Method 5 or 5I and consist of three test runs.
the average temperature at the inlet to the first PM control device (fabric filter or electrostatic precipitator) during the D/F performance test is 400 °F or less, this
limit is changed to 0.40 ng/dscm (TEQ).
3 Measured as propane.
4 Any source subject to the 24 ppmvd THC limit may elect to meet an alternative limit of 12 ppmvd for total organic HAP.
2 If
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C. What data collection activities were
conducted to support this action?
For the Portland Cement
Manufacturing Industry source category,
we did not submit data collection
requests to the industry or request
emissions testing by the industry for the
information used in this analysis. The
data and data sources used to support
this action are described in section II.D
below.
D. What other relevant background
information and data are available?
For the Portland Cement
Manufacturing Industry source category,
a comprehensive list of facilities and
kilns was compiled using information
from the EPA’s Greenhouse Gas
Reporting Program (GHGRP) (https://
www.epa.gov/ghgreporting). All
manufacturers of Portland cement are
required to report annually their
greenhouse gas emissions to the EPA (40
CFR part 98, subpart H). In reporting
year 2015, 95 Portland cement facilities
reported under the GHGRP. As
explained above in section II.B, kilns
that are fueled by hazardous waste are
subject to the hazardous waste
regulations in 40 CFR part 63, subpart
EEE and, therefore, are not subject to 40
CFR part 63, subpart LLL. Kilns that are
fueled by solid waste are subject to
regulations in 40 CFR part 60, subpart
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CCCC or DDDD and are also not subject
to subpart LLL. To assist in the
identification of which sources are
subject to subpart LLL, the
comprehensive list of Portland cement
manufacturing facilities was submitted
to the Portland Cement Association
(PCA) for review. The PCA is an
organization that represents the
manufacturers of cement. The PCA
provided information on the status of
each kiln and clinker cooler, whether or
not they were subject to subpart LLL
regulations, and identified other sources
at facilities, such as raw material dryers,
that were also subject to subpart LLL.
The risk modeling dataset was
developed in a two-step process.
Initially, a draft dataset was developed
using available information on
emissions, stack parameters, and
emission source locations. In step two,
the draft dataset for each Portland
cement manufacturing facility was
submitted to the facility or its parent
company to review for accuracy. Based
on the review by each company and the
submittal of documentation supporting
the changes, the risk modeling dataset
was revised. Copies of the datasets sent
to the companies for review and the
revised datasets and supporting
documentation submitted by each
company are contained in the docket to
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this rulemaking (Docket ID No. EPA–
HQ–OAR–2016–0442).
The initial draft dataset was
developed using emission test data to
the extent possible. Under 40 CFR part
63, subpart LLL, the EPA requires that
performance test results be submitted to
the EPA via the Compliance and
Emissions Data Reporting Interface
(CEDRI), which can be accessed through
the EPA’s Central Data Exchange (CDX).
Emissions data are publicly available
through the EPA’s Web Factor
Information Retrieval System (WebFIRE)
using the EPA’s electronic reporting tool
(ERT) as listed on the EPA’s ERT Web
site (https://www.epa.gov/electronicreporting-air-emissions/electronicreporting-tool-ert). To estimate actual
emissions, available emissions data
were extracted from each facility’s
submitted ERT file. When emissions
data were not available in ERT, the
subpart LLL emissions limit was
substituted as a placeholder for actual
emissions until the data set could be
reviewed and revised by industry.
III. Analytical Procedures
In this section, we describe the
analyses performed to support the
proposed decisions for the RTR and
other issues addressed in this proposal.
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A. How did we estimate post-MACT
risks posed by the source category?
The EPA conducted a risk assessment
that provides estimates of the MIR
posed by the HAP emissions from each
source in the source category, the
hazard index (HI) for chronic exposures
to HAP with the potential to cause noncancer health effects, and the hazard
quotient (HQ) for acute exposures to
HAP with the potential to cause noncancer health effects. The assessment
also provides estimates of the
distribution of cancer risks within the
exposed populations, cancer incidence,
and an evaluation of the potential for
adverse environmental effects. The eight
sections that follow this paragraph
describe how we estimated emissions
and conducted the risk assessment. The
docket for this rulemaking contains the
following document which provides
more information on the risk assessment
inputs and models: Residual Risk
Assessment for the Portland Cement
Manufacturing Industry Source
Category in Support of the Risk and
Technology Review September, 2017
Proposed Rule. The methods used to
assess risks (as described in the eight
primary steps below) are consistent with
those peer-reviewed by a panel of the
EPA’s Science Advisory Board (SAB) in
2009 and described in their peer review
report issued in 2010;2 they are also
consistent with the key
recommendations contained in that
report.
1. How did we estimate actual
emissions and identify the emissions
release characteristics?
The pollutants regulated under 40
CFR part 63, subpart LLL are PM, HCl,
THC, mercury, and D/F. The emission
standards apply to Portland cement
plants that are major or area sources,
with one exception. Kilns that are
located at a facility that is an area source
are not subject to the emission limits for
HCl. Sources subject to the emissions
limit for THC may elect to meet an
alternative limit for total organic HAP.
For purposes of subpart LLL, total
organic HAP is the sum of the
concentrations of compounds of
formaldehyde, benzene, toluene,
styrene, m-xylene, p-xylene, o-xylene,
acetaldehyde, and naphthalene as
measured by EPA Test Method 320 or
Method 18 of appendix A to 40 CFR part
63 or ASTM D6348–03 or a combination
of these methods, as appropriate. The
2 U.S. EPA SAB. Risk and Technology Review
(RTR) Risk Assessment Methodologies: For Review
by the EPA’s Science Advisory Board with Case
Studies—MACT I Petroleum Refining Sources and
Portland Cement Manufacturing, May 2010.
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affected sources at Portland cement
plants that were accounted for in the
risk modeling dataset include the kiln,
as well as any alkali bypass or inline
raw mill or inline coal mill, clinker
coolers, and raw material dryers. Kilns
fueled with hazardous waste or solid
waste and not subject to subpart LLL
were excluded from the dataset. All
affected sources in the risk modeling
dataset emit through stacks. As
mentioned in section II.D above, the risk
modeling dataset used for estimating
actual emissions was developed in a
two-step process. Initially, the dataset
was developed using available
information and is described below. The
dataset for each Portland cement
manufacturing facility was then
submitted to the facility, or its parent
company, to review for accuracy. Based
on the review by each company, and the
submittal of documentation supporting
the changes, the risk modeling dataset
was then revised. Copies of the datasets
sent to the companies for review and the
revised datasets submitted by each
company are contained in the docket to
this rulemaking (Docket ID No. EPA–
HQ–OAR–2016–0442).
As described in section II.D above,
available emissions data were extracted
from each facility’s submitted ERT file.
To ensure that the emissions data reflect
process and control device changes
made at each Portland cement plant to
comply with the 2013 final amendments
to 40 CFR part 63, subpart LLL
(February 12, 2013, 78 FR 10006),
emissions data from mid-2015 and later
were used as inputs into the emissions
modeling file.
Emissions data are reported in ERT in
units of pounds per hour (lb/hr), which
were multiplied by a facility’s reported
annual hours of operation to calculate
emissions in tpy. If hours of operation
were not reported, the default of 8,760
hours per year was used. When
emissions data were not available in
ERT, the 40 CFR part 63, subpart LLL
emissions limit was substituted as a
placeholder for actual emissions until
the data set could be reviewed and
revised by industry.
Subpart LLL of 40 CFR part 63 uses
PM as a surrogate for non-mercury
metallic HAP and THC as a surrogate for
organic HAP. The specific non-mercury
metallic HAP that went into the
modeling file are antimony, arsenic,
beryllium, cadmium, chromium, cobalt,
lead, manganese, mercury, nickel, and
selenium. As an alternative to
measuring THC, subpart LLL allows
sources to measure directly their
emissions of the nine organic HAP
listed in subpart LLL. The specific
organic HAP that went into the
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modeling file are acetaldehyde,
formaldehyde, naphthalene, styrene,
toluene, m-xylene, o-xylene, p-xylene,
and benzene. Because subpart LLL
compliance testing is typically
performed for the surrogates PM and
THC, there are limited test data
available for compound-specific nonmercury metallic and organic HAP
emissions. To generate compoundspecific metallic HAP and organic HAP
emissions estimates, recent emissions
tests were identified in which testing
was done for compound-specific
metallic and organic HAP emissions. To
account for recent changes in emission
controls and production processes that
have been implemented by facilities to
comply with the subpart LLL MACT
standards, emissions testing that
occurred in 2015 and later were used to
develop compound-specific estimates
for metallic HAP and organic HAP
emissions. In the case of D/F, the
subpart LLL emission limits for D/F
were unchanged in the 2013 final rule.
Thus, older D/F test data could be used
along with more recent test data.
The approach used to develop the
final risk modeling dataset assures the
quality of the data at various steps in the
process of developing the dataset. The
initial step in developing the dataset
was to compile a list of affected
facilities. A comprehensive list of
cement manufacturing facilities and
kilns was derived from the EPA’s
GHGRP, which requires reporting by all
cement manufacturing facilities. Not all
Portland cement kilns are subject to 40
CFR part 63, subpart LLL. Kilns that
burn commercial and industrial solid
waste are subject to 40 CFR part 60,
subpart CCCC and DDDD. Kilns that
burn hazardous waste are subject to 40
CFR part 63, subpart EEE. To help
identify the cement kilns that are
subject to subpart LLL regulations, the
list of facilities and kilns was submitted
to the PCA for review. In their review,
they provided useful information on
which cement manufacturing facilities
were or were not subject to subpart LLL,
whether kilns and clinker coolers used
separate or combined stacks, the
presence of additional affected sources
not on the initial list, and the presence
of kilns that were not currently
operating. For those kilns identified as
not currently operating, the appropriate
state permitting agency was contacted to
determine whether the kiln was
currently permitted to operate. If the
kiln was not operating, but retained
their title V permit, they were kept in
the dataset. In other instances, company
representatives were contacted to verify
that kilns at their facilities were or were
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not subject to subpart LLL regulations.
In developing the emissions data,
operating hours, stack parameters (i.e.,
stack height, temperature, diameter,
velocity, and flowrate), and stack
locations (i.e., latitude and longitude),
the use of the EPA’s ERT provides a
single source of electronic test data and
replaces the manual collection and
evaluation of test data. The regulated
facility owner or operator submits their
summary report semiannually to the
EPA via the CEDRI, which is accessed
through the EPA’s CDX (www.epa.gov/
cdx). This electronic submission of data
helps to ensure that information and
procedures required by test methods are
documented, provides consistent
criteria to quantitatively characterize the
quality of the data collected during the
emissions test, and standardizes the
reporting of results. Information on
stack parameters and stack locations
were also derived from ERT. For
facilities that had not yet submitted
their test information to ERT, the
emission limits were used as
placeholders until industry could
review the information. When operating
hours were not in ERT, a placeholder of
8,760 hours was used until industry
could review the information. When
stack parameters and stack locations
were not in ERT, other sources of
information such as the 2013 Universal
Industrial Sectors Integrated Solutions
(UISIS) modeling file created by the
EPA and the 2011 National Emissions
Inventory (NEI) were used. As a check
on the emissions data, operating hours,
stack parameters, and stack locations
compiled for each facility, a draft of the
dataset consisting of the data for all the
facilities under a single company was
sent to a representative at the
appropriate company for review.
Instructions for reviewing and making
changes to the dataset required that any
revisions be supported with appropriate
documentation. In addition, example
calculations for emissions estimates and
default stack parameters were provided.
Revisions made to the data for each
facility were incorporated into a master
final dataset. The master final dataset
was subjected to further quality
evaluation. For example, exhaust gas
flowrates were checked using
information on stack diameters and gas
velocities. Stack diameters and stack
velocities are checked for outliers. Stack
locations were also checked using
Google Earth® to ensure that stack
locations were correctly located at the
cement manufacturing facility.
The derivation of actual emission
estimates is discussed in more detail in
the document, Development of the RTR
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Risk Modeling Dataset for the Portland
Cement Manufacturing Industry Source
Category, which is available in the
docket for this proposed rulemaking.
2. How did we estimate MACTallowable emissions?
The available emissions data in the
RTR emissions dataset include estimates
of the mass of HAP emitted during the
specified annual time period. In some
cases, these ‘‘actual’’ emission levels are
lower than the emission levels required
to comply with the current MACT
standards. The emissions level allowed
to be emitted by the MACT standards is
referred to as the ‘‘MACT-allowable’’
emissions level. We discussed the use of
both MACT-allowable and actual
emissions in the final Coke Oven
Batteries RTR (70 FR 19998–19999,
April 15, 2005) and in the proposed and
final Hazardous Organic NESHAP RTRs
(71 FR 34428, June 14, 2006, and 71 FR
76609, December 21, 2006,
respectively). In those actions, we noted
that assessing the risks at the MACTallowable level is inherently reasonable
since these risks reflect the maximum
level facilities could emit and still
comply with national emission
standards. We also explained that it is
reasonable to consider actual emissions,
where such data are available, in both
steps of the risk analysis, in accordance
with the Benzene NESHAP approach
(54 FR 38044, September 14, 1989).
Allowable emissions are calculated
using the emission limits in the rule for
existing sources along with the emission
factors for metallic HAP, organic HAP,
and D/F congeners, the annual
production capacity, and, when the
emission limit is a concentration-based
limit, the annual hours of operation
reported by each source. We note that
these are conservative estimates of
allowable emissions. It is unlikely that
emissions would be at the maximum
limit at all times because sources cannot
emit HAP at a level that is exactly equal
to the limit and remain in compliance
with the standard due to day-to-day
variability in process operations and
emissions. On average, facilities must
emit at some level below the MACT
limit to ensure that they are always in
compliance. The derivation of allowable
emissions is discussed in more detail in
the document, Development of the RTR
Risk Modeling Dataset for the Portland
Cement Manufacturing Industry Source
Category, which is available in the
docket for this proposed rulemaking.
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3. How did we conduct dispersion
modeling, determine inhalation
exposures, and estimate individual and
population inhalation risks?
Both long-term and short-term
inhalation exposure concentrations and
health risks from the source category
addressed in this proposal were
estimated using the Human Exposure
Model (Community and Sector HEM–3).
The HEM–3 performs three primary risk
assessment activities: (1) conducting
dispersion modeling to estimate the
concentrations of HAP in ambient air,
(2) estimating long-term and short-term
inhalation exposures to individuals
residing within 50 kilometers (km) of
the modeled sources,3 and (3)
estimating individual and populationlevel inhalation risks using the exposure
estimates and quantitative doseresponse information.
The air dispersion model used by the
HEM–3 model (AERMOD) is one of the
EPA’s preferred models for assessing
pollutant concentrations from industrial
facilities.4 To perform the dispersion
modeling and to develop the
preliminary risk estimates, HEM–3
draws on three data libraries. The first
is a library of meteorological data,
which is used for dispersion
calculations. This library includes 1
year (2016) of hourly surface and upper
air observations for more than 800
meteorological stations, selected to
provide coverage of the U.S. and Puerto
Rico. A second library of U.S. Census
Bureau census block 5 internal point
locations and populations provides the
basis of human exposure calculations
(U.S. Census, 2010). In addition, for
each census block, the census library
includes the elevation and controlling
hill height, which are also used in
dispersion calculations. A third library
of pollutant unit risk factors and other
health benchmarks is used to estimate
health risks. These risk factors and
health benchmarks are the latest values
recommended by the EPA for HAP and
other toxic air pollutants. These values
are available at https://www.epa.gov/
fera/dose-response-assessmentassessing-health-risks-associatedexposure-hazardous-air-pollutants and
are discussed in more detail later in this
section.
In developing the risk assessment for
chronic exposures, we used the
3 This metric comes from the Benzene NESHAP.
See 54 FR 38046, September 14, 1989.
4 U.S. EPA. Revision to the Guideline on Air
Quality Models: Adoption of a Preferred General
Purpose (Flat and Complex Terrain) Dispersion
Model and Other Revisions (70 FR 68218,
November 9, 2005).
5 A census block is the smallest geographic area
for which census statistics are tabulated.
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estimated annual average ambient air
concentrations of each HAP emitted by
each source for which we have
emissions data in the source category.
The air concentrations at each nearby
census block centroid were used as a
surrogate for the chronic inhalation
exposure concentration for all the
people who reside in that census block.
We calculated the MIR for each facility
as the cancer risk associated with a
continuous lifetime (24 hours per day,
7 days per week, and 52 weeks per year
for a 70-year period) exposure to the
maximum concentration at the centroid
of inhabited census blocks. Individual
cancer risks were calculated by
multiplying the estimated lifetime
exposure to the ambient concentration
of each of the HAP (in micrograms per
cubic meter (mg/m3)) by its unit risk
estimate (URE). The URE is an upper
bound estimate of an individual’s
probability of contracting cancer over a
lifetime of exposure to a concentration
of 1 microgram of the pollutant per
cubic meter of air. For residual risk
assessments, we generally use URE
values from the EPA’s Integrated Risk
Information System (IRIS). For
carcinogenic pollutants without IRIS
values, we look to other reputable
sources of cancer dose-response values,
often using California EPA (CalEPA)
URE values, where available. In cases
where new, scientifically credible dose
response values have been developed in
a manner consistent with the EPA
guidelines and have undergone a peer
review process similar to that used by
the EPA, we may use such doseresponse values in place of, or in
addition to, other values, if appropriate.
The EPA estimated incremental
individual lifetime cancer risks
associated with emissions from the
facilities in the source category as the
sum of the risks for each of the
carcinogenic HAP (including those
classified as carcinogenic to humans,
likely to be carcinogenic to humans, and
suggestive evidence of carcinogenic
potential 6) emitted by the modeled
6 These classifications also coincide with the
terms ‘‘known carcinogen, probable carcinogen, and
possible carcinogen,’’ respectively, which are the
terms advocated in the EPA’s previous Guidelines
for Carcinogen Risk Assessment, published in 1986
(51 FR 33992, September 24, 1986). In August 2000,
the document, Supplemental Guidance for
Conducting Health Risk Assessment of Chemical
Mixtures (EPA/630/R–00/002) was published as a
supplement to the 1986 document. Copies of both
documents can be obtained from https://cfpub.
epa.gov/ncea/risk/recordisplay.cfm?deid=20533&
CFID=70315376&CFTOKEN=71597944. Summing
the risks of these individual compounds to obtain
the cumulative cancer risks is an approach that was
recommended by the EPA’s SAB in their 2002 peer
review of the EPA’s National Air Toxics Assessment
(NATA) titled, NATA—Evaluating the National-
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sources. Cancer incidence and the
distribution of individual cancer risks
for the population within 50 km of the
sources were also estimated for the
source category as part of this
assessment by summing individual
risks. A distance of 50 km is consistent
with both the analysis supporting the
1989 Benzene NESHAP (54 FR 38044,
September 14, 1989) and the limitations
of Gaussian dispersion models,
including AERMOD.
To assess the risk of non-cancer
health effects from chronic exposures,
we summed the HQ for each of the HAP
that affects a common target organ
system to obtain the HI for that target
organ system (or target organ-specific
HI, TOSHI). The HQ is the estimated
exposure divided by the chronic
reference value, which is a value
selected from one of several sources.
First, the chronic reference level can be
the EPA reference concentration (RfC)
(https://iaspub.epa.gov/sor_internet/
registry/termreg/searchandretrieve/
glossariesandkeywordlists/search.do?
details=&vocabName=
IRIS%20Glossary), defined as ‘‘an
estimate (with uncertainty spanning
perhaps an order of magnitude) of a
continuous inhalation exposure to the
human population (including sensitive
subgroups) that is likely to be without
an appreciable risk of deleterious effects
during a lifetime.’’ Alternatively, in
cases where an RfC from the EPA’s IRIS
database is not available or where the
EPA determines that using a value other
than the RfC is appropriate, the chronic
reference level can be a value from the
following prioritized sources: (1) The
Agency for Toxic Substances and
Disease Registry (ATSDR) Minimal Risk
Level (MRL) (https://www.atsdr.cdc.gov/
mrls/index.asp), which is defined as ‘‘an
estimate of daily human exposure to a
hazardous substance that is likely to be
without an appreciable risk of adverse
non-cancer health effects (other than
cancer) over a specified duration of
exposure’’; (2) the CalEPA Chronic
Reference Exposure Level (REL) (https://
oehha.ca.gov/air/crnr/notice-adoptionair-toxics-hot-spots-program-guidancemanual-preparation-health-risk-0),
which is defined as ‘‘the concentration
level (that is expressed in units of
mg/m3 for inhalation exposure and in a
dose expressed in units of milligram per
kilogram-day (mg/kg-day) for oral
exposures), at or below which no
adverse health effects are anticipated for
a specified exposure duration’’; or (3), as
scale Air Toxics Assessment 1996 Data—an SAB
Advisory, available at https://yosemite.epa.gov/sab/
sabproduct.nsf/214C6E915BB04E14852570
CA007A682C/$File/ecadv02001.pdf.
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noted above, a scientifically credible
dose-response value that has been
developed in a manner consistent with
the EPA guidelines and has undergone
a peer review process similar to that
used by the EPA, in place of or in
concert with other values.
As mentioned above, in order to
characterize non-cancer chronic effects,
and in response to key
recommendations from the SAB, the
EPA selects dose-response values that
reflect the best available science for all
HAP included in RTR risk assessments.7
More specifically, for a given HAP, the
EPA examines the availability of
inhalation reference values from the
sources included in our tiered approach
(e.g., IRIS first, ATSDR second, CalEPA
third) and determines which inhalation
reference value represents the best
available science. Thus, as new
inhalation reference values become
available, the EPA will typically
evaluate them and determine whether
they should be given preference over
those currently being used in RTR risk
assessments.
The EPA also evaluated screening
estimates of acute exposures and risks
for each of the HAP (for which
appropriate acute dose-response values
are available) at the point of highest
potential off-site exposure for each
facility. To do this, the EPA estimated
the risks when both the peak hourly
emissions rate and worst-case
dispersion conditions occur. We also
assume that a person is located at the
point of highest impact during that same
time. In accordance with our mandate in
section 112 of the CAA, we use the
point of highest off-site exposure to
assess the potential risk to the
maximally exposed individual. The
acute HQ is the estimated acute
exposure divided by the acute doseresponse value. In each case, the EPA
calculated acute HQ values using best
available, short-term dose-response
values. These acute dose-response
values, which are described below,
include the acute REL, acute exposure
guideline levels (AEGL) and Emergency
Response Planning Guidelines (ERPG)
for 1-hour exposure durations. As
discussed below, we used conservative
assumptions for emissions rates,
meteorology, and exposure location.
As described in the CalEPA’s Air
Toxics Hot Spots Program Risk
7 Recommendations from the SAB’s review of
RTR Risk Assessment Methodologies and the
review materials are available at https://yosemite.
epa.gov/sab/sabproduct.nsf/4AB3966E263
D943A8525771F00668381/$File/EPA-SAB-10-007unsigned.pdf and at https://cfpub.epa.gov/si/si_
publiclowbar;record_report.cfm?dirEntryID=
238928, respectively.
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Assessment Guidelines, Part I, The
Determination of Acute Reference
Exposure Levels for Airborne Toxicants,
an acute REL value (https://oehha.ca.
gov/air/general-info/oehha-acute-8hour-and-chronic-reference-exposurelevel-rel-summary) is defined as ‘‘the
concentration level at or below which
no adverse health effects are anticipated
for a specified exposure duration.’’ Id. at
page 2. Acute REL values are based on
the most sensitive, relevant, adverse
health effect reported in the peerreviewed medical and toxicological
literature. Acute REL values are
designed to protect the most sensitive
individuals in the population through
the inclusion of margins of safety.
Because margins of safety are
incorporated to address data gaps and
uncertainties, exceeding the REL does
not automatically indicate an adverse
health impact.
AEGL values were derived in
response to recommendations from the
National Research Council (NRC). The
National Advisory Committee (NAC) for
the Development of Acute Exposure
Guideline Levels for Hazardous
Substances, usually referred to as the
AEGL Committee or the NAC/AEGL
committee, developed AEGL values for
at least 273 of the 329 chemicals on the
AEGL priority chemical list. The last
meeting of the NAC/AEGL Committee
was in April 2010, and its charter
expired in October 2011. The NAC/
AEGL Committee ended in October
2011, but the AEGL program continues
to operate at the EPA and works with
the National Academies to publish final
AEGLs (https://www.epa.gov/aegl).
As described in Standing Operating
Procedures (SOP) of the National
Advisory Committee on Acute Exposure
Guideline Levels for Hazardous
Chemicals (https://www.epa.gov/sites/
production/files/2015–09/documents/
sop_final_standing_operating_
procedures_2001.pdf),8 ‘‘the NRC’s
previous name for acute exposure
levels—community emergency exposure
levels—was replaced by the term AEGL
to reflect the broad application of these
values to planning, response, and
prevention in the community, the
workplace, transportation, the military,
and the remediation of Superfund
sites.’’ Id. at 2. This document also
states that AEGL values ‘‘represent
threshold exposure limits for the general
public and are applicable to emergency
8 National Academy of Sciences (NAS), 2001.
Standing Operating Procedures for Developing
Acute Exposure Levels for Hazardous Chemicals,
page 2.
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exposures ranging from 10 minutes to
eight hours.’’ Id. at 2.
The document lays out the purpose
and objectives of AEGL by stating that
‘‘the primary purpose of the AEGL
program and the National Advisory
Committee for Acute Exposure
Guideline Levels for Hazardous
Substances is to develop guideline
levels for once-in-a-lifetime, short-term
exposures to airborne concentrations of
acutely toxic, high-priority chemicals.’’
Id. at 21. In detailing the intended
application of AEGL values, the
document states that ‘‘[i]t is anticipated
that the AEGL values will be used for
regulatory and nonregulatory purposes
by U.S. Federal and state agencies and
possibly the international community in
conjunction with chemical emergency
response, planning, and prevention
programs. More specifically, the AEGL
values will be used for conducting
various risk assessments to aid in the
development of emergency
preparedness and prevention plans, as
well as real-time emergency response
actions, for accidental chemical releases
at fixed facilities and from transport
carriers.’’ Id. at 31.
The AEGL–1 value is then specifically
defined as ‘‘the airborne concentration
(expressed as ppm (parts per million) or
mg/m3 (milligrams per cubic meter)) of
a substance above which it is predicted
that the general population, including
susceptible individuals, could
experience notable discomfort,
irritation, or certain asymptomatic
nonsensory effects. However, the effects
are not disabling and are transient and
reversible upon cessation of exposure.’’
Id. at 3. The document also notes that,
‘‘Airborne concentrations below AEGL–
1 represent exposure levels that can
produce mild and progressively
increasing but transient and
nondisabling odor, taste, and sensory
irritation or certain asymptomatic,
nonsensory effects.’’ Id. Similarly, the
document defines AEGL–2 values as
‘‘the airborne concentration (expressed
as parts per million or milligrams per
cubic meter) of a substance above which
it is predicted that the general
population, including susceptible
individuals, could experience
irreversible or other serious, long-lasting
adverse health effects or an impaired
ability to escape.’’ Id.
ERPG values are derived for use in
emergency response, as described in the
American Industrial Hygiene
Association’s Emergency Response
Planning (ERP) Committee document
titled, ERPGS Procedures and
Responsibilities (https://www.aiha.org/
get-involved/AIHAGuideline
Foundation/EmergencyResponse
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44263
PlanningGuidelines/Documents/ERPG
%20Committee%20Standard%20
Operating%20Procedures%20%20-%20
March%202014%20Revision%20%28
Updated%2010-2-2014%29.pdf), which
states that, ‘‘Emergency Response
Planning Guidelines were developed for
emergency planning and are intended as
health based guideline concentrations
for single exposures to chemicals.’’ 9 Id.
at 1. The ERPG–1 value is defined as
‘‘the maximum airborne concentration
below which it is believed that nearly
all individuals could be exposed for up
to 1 hour without experiencing other
than mild transient adverse health
effects or without perceiving a clearly
defined, objectionable odor.’’ Id. at 2.
Similarly, the ERPG–2 value is defined
as ‘‘the maximum airborne
concentration below which it is
believed that nearly all individuals
could be exposed for up to one hour
without experiencing or developing
irreversible or other serious health
effects or symptoms which could impair
an individual’s ability to take protective
action.’’ Id. at 1.
As can be seen from the definitions
above, the AEGL and ERPG values
include the similarly-defined severity
levels 1 and 2. For many chemicals, a
severity level 1 value AEGL or ERPG has
not been developed because the types of
effects for these chemicals are not
consistent with the AEGL–1/ERPG–1
definitions; in these instances, we
compare higher severity level AEGL–2
or ERPG–2 values to our modeled
exposure levels to screen for potential
acute concerns. When AEGL–1/ERPG–1
values are available, they are used in
our acute risk assessments.
Acute REL values for 1-hour exposure
durations are typically lower than their
corresponding AEGL–1 and ERPG–1
values. Even though their definitions are
slightly different, AEGL–1 values are
often the same as the corresponding
ERPG–1 values, and AEGL–2 values are
often equal to ERPG–2 values.
Maximum HQ values from our acute
screening risk assessments typically
result when basing them on the acute
REL value for a particular pollutant. In
cases where our maximum acute HQ
value exceeds 1, we also report the HQ
value based on the next highest acute
dose-response value (usually the AEGL–
1 and/or the ERPG–1 value).
To develop screening estimates of
acute exposures in the absence of hourly
emissions data, generally we first
develop estimates of maximum hourly
emissions rates by multiplying the
9 ERP Committee Procedures and Responsibilities.
March 2014. American Industrial Hygiene
Association.
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average actual annual hourly emissions
rates by a default factor to cover
routinely variable emissions. We choose
the factor to use partially based on
process knowledge and engineering
judgment. The factor chosen also
reflects a Texas study of short-term
emissions variability, which showed
that most peak emission events in a
heavily-industrialized four-county area
(Harris, Galveston, Chambers, and
Brazoria Counties, Texas) were less than
twice the annual average hourly
emissions rate. The highest peak
emissions event was 74 times the
annual average hourly emissions rate,
and the 99th percentile ratio of peak
hourly emissions rate to the annual
average hourly emissions rate was 9.10
Considering this analysis, to account for
more than 99 percent of the peak hourly
emissions, we apply a conservative
screening multiplication factor of 10 to
the average annual hourly emissions
rate in our acute exposure screening
assessments as our default approach. A
further discussion of why this factor
was chosen can be found in the
memorandum, Emissions Data and
Acute Risk Factor Used in Residual Risk
Modeling: Portland Cement
Manufacturing Industry, available in the
docket for this rulemaking.
As part of our acute risk assessment
process, for cases where acute HQ
values from the screening step are less
than or equal to 1 (even under the
conservative assumptions of the
screening analysis), acute impacts are
deemed negligible and no further
analysis is performed for these HAP. In
cases where an acute HQ from the
screening step is greater than 1,
additional site-specific data are
considered to develop a more refined
estimate of the potential for acute
impacts of concern. For this source
category, since no HQ was greater than
1, no further analysis was performed.
Ideally, we would prefer to have
continuous measurements over time to
see how the emissions vary by each
hour over an entire year. Having a
frequency distribution of hourly
emissions rates over a year would allow
us to perform a probabilistic analysis to
estimate potential threshold
exceedances and their frequency of
occurrence. Such an evaluation could
include a more complete statistical
treatment of the key parameters and
10 Allen, et al., 2004. Variable Industrial VOC
Emissions and their impact on ozone formation in
the Houston Galveston Area. Texas Environmental
Research Consortium. https://
www.researchgate.net/publication/237593060_
Variable_Industrial_VOC_Emissions and_their_
Impact_on_Ozone_Formation_in_the_Houston_
Galveston_Area.
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elements adopted in this screening
analysis. Recognizing that this level of
data is rarely available, we instead rely
on the multiplier approach.
To better characterize the potential
health risks associated with estimated
acute exposures to HAP, and in
response to a key recommendation from
the SAB’s 2010 peer review of the EPA’s
RTR risk assessment methodologies,11
we generally examine a wider range of
available acute health metrics (e.g.,
RELs, AEGLs) than we do for our
chronic risk assessments. This is in
response to the SAB’s acknowledgement
that there are generally more data gaps
and inconsistencies in acute reference
values than there are in chronic
reference values. In some cases, when
Reference Value Arrays 12 for HAP have
been developed, we consider additional
acute values (i.e., occupational and
international values) to provide a more
complete risk characterization.
4. How did we conduct the
multipathway exposure and risk
screening?
The EPA conducted a screening
analysis examining the potential for
significant human health risks due to
exposures via routes other than
inhalation (i.e., ingestion). We first
determined whether any sources in the
source category emitted any HAP
known to be persistent and
bioaccumulative in the environment
(PB–HAP). The PB–HAP compounds or
compound classes are identified for the
screening from the EPA’s Air Toxics
Risk Assessment Library (available at
https://www2.epa.gov/fera/riskassessment-and-modeling-air-toxicsrisk-assessment-reference-library).
For the Portland Cement
Manufacturing Industry source category,
we identified emissions of lead
compounds, cadmium compounds,
mercury compounds, arsenic
compounds, and D/F. Because one or
more of these PB–HAP are emitted by at
least one facility in the Portland Cement
Manufacturing Industry source category,
we proceeded to the next step of the
evaluation. In this step, we determined
whether the facility-specific emission
rates of the emitted PB–HAP were large
11 The SAB peer review of RTR Risk Assessment
Methodologies is available at https://yosemite.
epa.gov/sab/sabproduct.nsf/4AB3966E263D943A
8525771F00668381/$File/EPA-SAB-10-007unsigned.pdf.
12 U.S. EPA. Chapter 2.9, Chemical Specific
Reference Values for Formaldehyde in Graphical
Arrays of Chemical-Specific Health Effect Reference
Values for Inhalation Exposures (Final Report). U.S.
Environmental Protection Agency, Washington, DC,
EPA/600/R–09/061, 2009, and available online at
https://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?
deid=211003.
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enough to create the potential for
significant non-inhalation human health
risks under reasonable worst-case
conditions. To facilitate this step, we
developed screening threshold emission
rates for several PB–HAP using a
hypothetical upper-end screening
exposure scenario developed for use in
conjunction with the EPA’s Total Risk
Integrated Methodology.Fate, Transport,
and Ecological Exposure (TRIM.FaTE)
model. The PB–HAP with screening
threshold emission rates are: Cadmium
compounds, mercury compounds,
arsenic compounds, and D/F and
polycyclic organic matter (POM). We
conducted a sensitivity analysis on the
screening scenario to ensure that its key
design parameters would represent the
upper end of the range of possible
values, such that it would represent a
conservative, but not impossible
scenario. The facility-specific PB–HAP
emission rates were compared to their
respective screening threshold emission
rate to assess the potential for
significant human health risks via noninhalation pathways. We call this
application of the TRIM.FaTE model the
Tier 1 TRIM-screen or Tier 1 screen.
For the purpose of developing
emission rates for the Tier 1 TRIMscreen, we derived emission levels for
these PB–HAP (other than lead
compounds) at which the maximum
excess lifetime cancer risk would be 1in-1 million (i.e., D/F, arsenic
compounds, and POM) or, for HAP that
cause non-cancer health effects (i.e.,
cadmium compounds and mercury
compounds), the maximum HQ would
be 1. If the emission rate of any PB–HAP
included in the Tier 1 screen exceeds
the Tier 1 screening threshold emission
rates for any facility, we conduct a
second screen, which we call the Tier 2
TRIM-screen or Tier 2 screen.
In the Tier 2 screen, the location of
each facility that exceeds the Tier 1
screening threshold emission rates is
used to refine the assumptions
associated with the environmental
scenario while maintaining the
exposure scenario assumptions. A key
assumption that is part of the Tier 1
screen is that a lake is located near the
facility; we confirm the existence of
lakes near the facility as part of the Tier
2 screen. We also examine the
differences between local meteorology
near the facility and the meteorology
used in the Tier 1 screen. We then
adjust the risk-based Tier 1 screening
threshold emission rates for each PB–
HAP for each facility based on an
understanding of how exposure
concentrations estimated for the
screening scenario change with
meteorology and environmental
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assumptions. PB–HAP emissions that do
not exceed these new Tier 2 screening
threshold emission rates are considered
to be below a level of concern. If the
PB–HAP emissions for a facility exceed
the Tier 2 screening threshold emission
rates and data are available, we may
decide to conduct a more refined Tier 3
multipathway assessment or proceed to
a site-specific assessment. There are
several analyses that can be included in
a Tier 3 screen depending upon the
extent of refinement warranted,
including validating that the lakes are
fishable, considering plume-rise to
estimate emissions lost above the
mixing layer, and considering hourly
effects of meteorology and plume rise on
chemical fate and transport. For this
source category a Tier 3 screen was
conducted for 1 facility that had dioxin
emissions exceeding the Tier 2
threshold emission rates up to a value
of 100-in-1 million. If the Tier 3 screen
is exceeded, the EPA may conduct a
refined site-specific assessment.
When tiered screening values for any
facility indicate a potential health risk
to the public, we may conduct a more
refined multipathway assessment. A
refined assessment was conducted for
mercury in lieu of conducting a Tier 3
screen. To select the candidate facilities
for the site-specific assessment, we
analyzed the facilities with the
maximum exceedances of the Tier 2
screening values as well as the
combined effect from multiple facilities
on lakes within the same watershed. In
addition to looking at the Tier 2 screen
value for each lake, the location and
number of lakes or farms impacted for
each watershed was evaluated to assess
elevation/topography influences. A
review of the source category identified
3 facilities located in Midlothian, Texas,
as the best candidates for mercury
impacts. These candidate sites were
selected because of their exceedances of
the Tier 2 mercury screening value and
based upon the above considerations.
In evaluating the potential
multipathway risk from emissions of
lead compounds, rather than developing
a screening threshold emission rate for
them, we compared maximum
estimated 1-hour acute inhalation
exposures with the level of the current
National Ambient Air Quality Standard
(NAAQS) for lead.13 Values below the
level of the Primary (health-based) Lead
NAAQS were considered to have a low
potential for multipathway risk.
For further information on the
multipathway analysis approach, see
the Residual Risk Assessment for the
Portland Cement Manufacturing
Industry Source Category in Support of
the Risk and Technology Review
September 2017 Proposed Rule, which
is available in the docket for this action.
b. Environmental HAP
The EPA focuses on eight HAP, which
we refer to as ‘‘environmental HAP,’’ in
its screening analysis: Six PB–HAP and
two acid gases. The six PB–HAP are
cadmium compounds, D/F, arsenic
compounds, POM, mercury compounds
(both inorganic mercury and methyl
mercury), and lead compounds. The two
acid gases are HCl and hydrogen
fluoride (HF). The rationale for
including these eight HAP in the
environmental risk screening analysis is
presented below.
HAP that persist and bioaccumulate
are of particular environmental concern
because they accumulate in the soil,
sediment, and water. The PB–HAP are
taken up, through sediment, soil, water,
and/or ingestion of other organisms, by
plants or animals (e.g., small fish) at the
bottom of the food chain. As larger and
larger predators consume these
organisms, concentrations of the PB–
HAP in the animal tissues increases as
does the potential for adverse effects.
The six PB–HAP we evaluate as part of
our screening analysis account for 99.8
percent of all PB–HAP emissions
nationally from stationary sources (on a
mass basis from the 2005 EPA NEI).
In addition to accounting for almost
all of the mass of PB–HAP emitted, we
note that the TRIM.FaTE model that we
use to evaluate multipathway risk
allows us to estimate concentrations of
cadmium compounds, D/F, arsenic
compounds, POM, and mercury
compounds in soil, sediment, and
water. For lead compounds, we
currently do not have the ability to
calculate these concentrations using the
TRIM.FaTE model. Therefore, to
evaluate the potential for adverse
environmental effects from lead
compounds, we compare the estimated
HEM-modeled exposures from the
source category emissions of lead with
the level of the Secondary Lead
NAAQS.14 We consider values below
the level of the Secondary Lead NAAQS
to be unlikely to cause adverse
environmental effects.
Due to their well-documented
potential to cause direct damage to
terrestrial plants, we include two acid
gases, HCl and HF, in the environmental
screening analysis. According to the
2005 NEI, HCl and HF account for about
99 percent (on a mass basis) of the total
acid gas HAP emitted by stationary
sources in the U.S. In addition to the
potential to cause direct damage to
plants, high concentrations of HF in the
air have been linked to fluorosis in
livestock. Air concentrations of these
HAP are already calculated as part of
the human multipathway exposure and
risk screening analysis using the HEM3–
AERMOD air dispersion model, and we
are able to use the air dispersion
modeling results to estimate the
13 In doing so, the EPA notes that the legal
standard for a primary NAAQS—that a standard is
requisite to protect public health and provide an
adequate margin of safety (CAA section 109(b))—
differs from the CAA section 112(f) standard
(requiring, among other things, that the standard
provide an ‘‘ample margin of safety’’). However, the
Primary Lead NAAQS is a reasonable measure of
determining risk acceptability (i.e., the first step of
the Benzene NESHAP analysis) since it is designed
to protect the most susceptible group in the human
population—children, including children living
near major lead emitting sources. 73 FR 67002/3; 73
FR 67000/3; 73 FR 67005/1. In addition, applying
the level of the Primary Lead NAAQS at the risk
acceptability step is conservative, since that
Primary Lead NAAQS reflects an adequate margin
of safety.
14 The Secondary Lead NAAQS is a reasonable
measure of determining whether there is an adverse
environmental effect since it was established
considering ‘‘effects on soils, water, crops,
vegetation, man-made materials, animals, wildlife,
weather, visibility and climate, damage to and
deterioration of property, and hazards to
transportation, as well as effects on economic
values and on personal comfort and well-being.’’
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5. How did we assess risks considering
emissions control options?
In addition to assessing baseline
inhalation risks and screening for
potential multipathway risks, we also
estimated risks considering the potential
emission reductions that would be
achieved by the control options under
consideration. In these cases, the
expected emission reductions were
applied to the specific HAP and
emission points in the RTR emissions
dataset to develop corresponding
estimates of risk and incremental risk
reductions.
6. How did we conduct the
environmental risk screening
assessment?
a. Adverse Environmental Effect
The EPA conducts a screening
assessment to examine the potential for
adverse environmental effects as
required under section 112(f)(2)(A) of
the CAA. Section 112(a)(7) of the CAA
defines ‘‘adverse environmental effect’’
as ‘‘any significant and widespread
adverse effect, which may reasonably be
anticipated, to wildlife, aquatic life, or
other natural resources, including
adverse impacts on populations of
endangered or threatened species or
significant degradation of
environmental quality over broad
areas.’’
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potential for an adverse environmental
effect.
The EPA acknowledges that other
HAP beyond the eight HAP discussed
above may have the potential to cause
adverse environmental effects.
Therefore, the EPA may include other
relevant HAP in its environmental risk
screening in the future, as modeling
science and resources allow. The EPA
invites comment on the extent to which
other HAP emitted by the source
category may cause adverse
environmental effects. Such information
should include references to peerreviewed ecological effects benchmarks
that are of sufficient quality for making
regulatory decisions, as well as
information on the presence of
organisms located near facilities within
the source category that such
benchmarks indicate could be adversely
affected.
c. Ecological Assessment Endpoints and
Benchmarks for PB–HAP
An important consideration in the
development of the EPA’s screening
methodology is the selection of
ecological assessment endpoints and
benchmarks. Ecological assessment
endpoints are defined by the ecological
entity (e.g., aquatic communities,
including fish and plankton) and its
attributes (e.g., frequency of mortality).
Ecological assessment endpoints can be
established for organisms, populations,
communities or assemblages, and
ecosystems.
For PB–HAP (other than lead
compounds), we evaluated the
following community-level ecological
assessment endpoints to screen for
organisms directly exposed to HAP in
soils, sediment, and water:
• Local terrestrial communities (i.e.,
soil invertebrates, plants) and
populations of small birds and
mammals that consume soil
invertebrates exposed to PB–HAP in the
surface soil;
• Local benthic (i.e., bottom sediment
dwelling insects, amphipods, isopods,
and crayfish) communities exposed to
PB–HAP in sediment in nearby water
bodies; and
• Local aquatic (water-column)
communities (including fish and
plankton) exposed to PB–HAP in nearby
surface waters.
For PB–HAP (other than lead
compounds), we also evaluated the
following population-level ecological
assessment endpoint to screen for
indirect HAP exposures of top
consumers via the bioaccumulation of
HAP in food chains:
• Piscivorous (i.e., fish-eating)
wildlife consuming PB–HAP-
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contaminated fish from nearby water
bodies.
For cadmium compounds, D/F,
arsenic compounds, POM, and mercury
compounds, we identified the available
ecological benchmarks for each
assessment endpoint. An ecological
benchmark represents a concentration of
HAP (e.g., 0.77 mg of HAP per liter of
water) that has been linked to a
particular environmental effect level
through scientific study. For PB–HAP
we identified, where possible,
ecological benchmarks at the following
effect levels:
• Probable effect levels (PEL): Level
above which adverse effects are
expected to occur frequently;
• Lowest-observed-adverse-effect
level (LOAEL): The lowest exposure
level tested at which there are
biologically significant increases in
frequency or severity of adverse effects;
and
• No-observed-adverse-effect levels
(NOAEL): The highest exposure level
tested at which there are no biologically
significant increases in the frequency or
severity of adverse effect.
We established a hierarchy of
preferred benchmark sources to allow
selection of benchmarks for each
environmental HAP at each ecological
assessment endpoint. In general, the
EPA sources that are used at a
programmatic level (e.g., Office of
Water, Superfund Program) were used
in the analysis, if available. If not, the
EPA benchmarks used in Regional
programs (e.g., Superfund) were used. If
benchmarks were not available at a
programmatic or Regional level, we
used benchmarks developed by other
federal agencies (e.g., National Oceanic
and Atmospheric Administration
(NOAA)) or state agencies.
Benchmarks for all effect levels are
not available for all PB–HAP and
assessment endpoints. In cases where
multiple effect levels were available for
a particular PB–HAP and assessment
endpoint, we use all of the available
effect levels to help us to determine
whether ecological risks exist and, if so,
whether the risks could be considered
significant and widespread.
d. Ecological Assessment Endpoints and
Benchmarks for Acid Gases
The environmental screening analysis
also evaluated potential damage and
reduced productivity of plants due to
direct exposure to acid gases in the air.
For acid gases, we evaluated the
following ecological assessment
endpoint:
• Local terrestrial plant communities
with foliage exposed to acidic gaseous
HAP in the air.
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The selection of ecological
benchmarks for the effects of acid gases
on plants followed the same approach
as for PB–HAP (i.e., we examine all of
the available chronic benchmarks). For
HCl, the EPA identified chronic
benchmark concentrations. We note that
the benchmark for chronic HCl exposure
to plants is greater than the reference
concentration for chronic inhalation
exposure for human health. This means
that where the EPA includes regulatory
requirements to prevent an exceedance
of the reference concentration for
human health, additional analyses for
adverse environmental effects of HCl
would not be necessary.
For HF, the EPA identified chronic
benchmark concentrations for plants
and evaluated chronic exposures to
plants in the screening analysis. High
concentrations of HF in the air have also
been linked to fluorosis in livestock.
However, the HF concentrations at
which fluorosis in livestock occur are
higher than those at which plant
damage begins. Therefore, the
benchmarks for plants are protective of
both plants and livestock.
e. Screening Methodology
For the environmental risk screening
analysis, the EPA first determined
whether any facilities in the Portland
Cement Manufacturing Industry sources
emitted any of the eight environmental
HAP. For the Portland Cement
Manufacturing Industry source category,
we identified emissions of lead
compounds, cadmium compounds,
mercury compounds, arsenic
compounds, D/F, and HCl.
Because one or more of the eight
environmental HAP evaluated are
emitted by at least one facility in the
source category, we proceeded to the
second step of the evaluation.
f. PB–HAP Methodology
For cadmium compounds, arsenic
compounds, mercury compounds, POM,
and D/F, the environmental screening
analysis consists of two tiers, while lead
compounds are analyzed differently as
discussed earlier. In the first tier, we
determined whether the maximum
facility-specific emission rates of each of
the emitted environmental HAP were
large enough to create the potential for
adverse environmental effects under
reasonable worst-case environmental
conditions. These are the same
environmental conditions used in the
human multipathway exposure and risk
screening analysis.
To facilitate this step, TRIM.FaTE was
run for each PB–HAP under
hypothetical environmental conditions
designed to provide conservatively high
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HAP concentrations. The model was set
to maximize runoff from terrestrial
parcels into the modeled lake, which in
turn, maximized the chemical
concentrations in the water, the
sediments, and the fish. The resulting
media concentrations were then used to
back-calculate a screening level
emission rate that corresponded to the
relevant exposure benchmark
concentration value for each assessment
endpoint. To assess emissions from a
facility, the reported emission rate for
each PB–HAP was compared to the
screening level emission rate for that
PB–HAP for each assessment endpoint.
If emissions from a facility do not
exceed the Tier 1 screening level, the
facility ‘‘passes’’ the screen, and,
therefore, is not evaluated further under
the screening approach. If emissions
from a facility exceed the Tier 1
screening level, we evaluate the facility
further in Tier 2.
In Tier 2 of the environmental
screening analysis, the emission rate
screening levels are adjusted to account
for local meteorology and the actual
location of lakes in the vicinity of
facilities that did not pass the Tier 1
screen. The modeling domain for each
facility in the Tier 2 analysis consists of
8 octants. Each octant contains 5
modeled soil concentrations at various
distances from the facility (5 soil
concentrations × 8 octants = total of 40
soil concentrations per facility) and one
lake with modeled concentrations for
water, sediment, and fish tissue. In the
Tier 2 environmental risk screening
analysis, the 40 soil concentration
points are averaged to obtain an average
soil concentration for each facility for
each PB–HAP. For the water, sediment,
and fish tissue concentrations, the
highest value for each facility for each
pollutant is used. If emission
concentrations from a facility do not
exceed the Tier 2 screening level, the
facility passes the screen, and typically
is not evaluated further. If emissions
from a facility exceed the Tier 2
screening level, the facility does not
pass the screen and, therefore, may have
the potential to cause adverse
environmental effects. Such facilities
are evaluated further to investigate
factors such as the magnitude and
characteristics of the area of exceedance.
g. Acid Gas Methodology
The environmental screening analysis
evaluates the potential phytotoxicity
and reduced productivity of plants due
to chronic exposure to acid gases. The
environmental risk screening
methodology for acid gases is a singletier screen that compares the average
off-site ambient air concentration over
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the modeling domain to ecological
benchmarks for each of the acid gases.
Because air concentrations are
compared directly to the ecological
benchmarks, emission-based screening
levels are not calculated for acid gases.
For purposes of ecological risk
screening, the EPA identifies a potential
for adverse environmental effects to
plant communities from exposure to
acid gases when the average
concentration of the HAP around a
facility exceeds the LOAEL ecological
benchmark. In such cases, we further
investigate factors such as the
magnitude and characteristics of the
area of exceedance (e.g., land use of
exceedance area, size of exceedance
area) to determine if there is an adverse
environmental effect.
For further information on the
environmental screening analysis
approach, see the Residual Risk
Assessment for the Portland Cement
Manufacturing Industry Source
Category in Support of the Risk and
Technology Review September 2017
Proposed Rule, which is available in the
docket for this action.
7. How did we conduct facility-wide
assessments?
To put the source category risks in
context, we typically examine the risks
from the entire ‘‘facility,’’ where the
facility includes all HAP-emitting
operations within a contiguous area and
under common control. In other words,
we examine the HAP emissions not only
from the source category emission
points of interest, but also emissions of
HAP from all other emission sources at
the facility for which we have data. For
this source category, we conducted the
facility-wide assessment using the 2014
NEI. We analyzed risks due to the
inhalation of HAP that are emitted
‘‘facility-wide’’ for the populations
residing within 50 km of each facility,
consistent with the methods used for
the source category analysis described
above. For these facility-wide risk
analyses, the modeled source category
risks were compared to the facility-wide
risks to determine the portion of facilitywide risks that could be attributed to the
source category addressed in this
proposal. We specifically examined the
facility that was associated with the
highest estimate of risk and determined
the percentage of that risk attributable to
the source category of interest. The
Residual Risk Assessment for the
Portland Cement Manufacturing
Industry Source Category in Support of
the Risk and Technology Review
September 2017 Proposed Rule,
available through the docket for this
action, provides the methodology and
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results of the facility-wide analyses,
including all facility-wide risks and the
percentage of source category
contribution to facility-wide risks.
8. How did we consider uncertainties in
risk assessment?
In the Benzene NESHAP, we
concluded that risk estimation
uncertainty should be considered in our
decision-making under the ample
margin of safety framework. Uncertainty
and the potential for bias are inherent in
all risk assessments, including those
performed for this proposal. Although
uncertainty exists, we believe that our
approach, which used conservative
tools and assumptions, ensures that our
decisions are health protective and
environmentally protective. A brief
discussion of the uncertainties in the
RTR emissions dataset, dispersion
modeling, inhalation exposure
estimates, and dose-response
relationships follows below. A more
thorough discussion of these
uncertainties is included in the Residual
Risk Assessment for the Portland
Cement Manufacturing Industry Source
Category in Support of the Risk and
Technology Review September 2017
Proposed Rule, which is available in the
docket for this action.
a. Uncertainties in the RTR Emissions
Dataset
Although the development of the RTR
emissions dataset involved quality
assurance/quality control processes, the
accuracy of emissions values will vary
depending on the source of the data, the
degree to which data are incomplete or
missing, the degree to which
assumptions made to complete the
datasets are accurate, errors in emission
estimates, and other factors. The
emission estimates considered in this
analysis generally are annual totals for
certain years, and they do not reflect
short-term fluctuations during the
course of a year or variations from year
to year. The estimates of peak hourly
emission rates for the acute effects
screening assessment were based on an
emission adjustment factor applied to
the average annual hourly emission
rates, which are intended to account for
emission fluctuations due to normal
facility operations.
b. Uncertainties in Dispersion Modeling
We recognize there is uncertainty in
ambient concentration estimates
associated with any model, including
the EPA’s recommended regulatory
dispersion model, AERMOD. In using a
model to estimate ambient pollutant
concentrations, the user chooses certain
options to apply. For RTR assessments,
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we select some model options that have
the potential to overestimate ambient air
concentrations (e.g., not including
plume depletion or pollutant
transformation). We select other model
options that have the potential to
underestimate ambient impacts (e.g., not
including building downwash). Other
options that we select have the potential
to either under- or overestimate ambient
levels (e.g., meteorology and receptor
locations). On balance, considering the
directional nature of the uncertainties
commonly present in ambient
concentrations estimated by dispersion
models, the approach we apply in the
RTR assessments should yield unbiased
estimates of ambient HAP
concentrations.
c. Uncertainties in Inhalation Exposure
The EPA did not include the effects
of human mobility on exposures in the
assessment. Specifically, short-term
mobility and long-term mobility
between census blocks in the modeling
domain were not considered.15 The
approach of not considering short or
long-term population mobility does not
bias the estimate of the theoretical MIR
(by definition), nor does it affect the
estimate of cancer incidence because the
total population number remains the
same. It does, however, affect the shape
of the distribution of individual risks
across the affected population, shifting
it toward higher estimated individual
risks at the upper end and reducing the
number of people estimated to be at
lower risks, thereby increasing the
estimated number of people at specific
high risk levels (e.g., 1-in-10 thousand
or 1-in-1 million).
In addition, the assessment predicted
the chronic exposures at the centroid of
each populated census block as
surrogates for the exposure
concentrations for all people living in
that block. Using the census block
centroid to predict chronic exposures
tends to over-predict exposures for
people in the census block who live
farther from the facility and underpredict exposures for people in the
census block who live closer to the
facility. Thus, using the census block
centroid to predict chronic exposures
may lead to a potential understatement
or overstatement of the true maximum
impact, but is an unbiased estimate of
average risk and incidence. We reduce
this uncertainty by analyzing large
census blocks near facilities using aerial
imagery and adjusting the location of
15 Short-term mobility is movement from one
micro-environment to another over the course of
hours or days. Long-term mobility is movement
from one residence to another over the course of a
lifetime.
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the block centroid to better represent the
population in the block, as well as
adding additional receptor locations
where the block population is not well
represented by a single location.
The assessment evaluates the cancer
inhalation risks associated with
pollutant exposures over a 70-year
period, which is the assumed lifetime of
an individual. In reality, both the length
of time that modeled emission sources
at facilities actually operate (i.e., more
or less than 70 years) and the domestic
growth or decline of the modeled
industry (i.e., the increase or decrease in
the number or size of domestic
facilities) will influence the future risks
posed by a given source or source
category. Depending on the
characteristics of the industry, these
factors will, in most cases, result in an
overestimate both in individual risk
levels and in the total estimated number
of cancer cases. However, in the
unlikely scenario where a facility
maintains, or even increases, its
emissions levels over a period of more
than 70 years, residents live beyond 70
years at the same location, and the
residents spend most of their days at
that location, then the cancer inhalation
risks could potentially be
underestimated. However, annual
cancer incidence estimates from
exposures to emissions from these
sources would not be affected by the
length of time an emissions source
operates.
The exposure estimates used in these
analyses assume chronic exposures to
ambient (outdoor) levels of pollutants.
Because most people spend the majority
of their time indoors, actual exposures
may not be as high, depending on the
characteristics of the pollutants
modeled. For many of the HAP, indoor
levels are roughly equivalent to ambient
levels, but for very reactive pollutants or
larger particles, indoor levels are
typically lower. This factor has the
potential to result in an overestimate of
25 to 30 percent of exposures.16
In addition to the uncertainties
highlighted above, there are several
factors specific to the acute exposure
assessment that the EPA conducts as
part of the risk review under section 112
of the CAA that should be highlighted.
The accuracy of an acute inhalation
exposure assessment depends on the
simultaneous occurrence of
independent factors that may vary
greatly, such as hourly emissions rates,
meteorology, and the presence of
humans at the location of the maximum
16 U.S.
EPA. National-Scale Air Toxics
Assessment for 1996. (EPA 453/R–01–003; January
2001; page 85.)
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concentration. In the acute screening
assessment that we conduct under the
RTR program, we assume that peak
emissions from the source category and
worst-case meteorological conditions
co-occur, thus, resulting in maximum
ambient concentrations. These two
events are unlikely to occur at the same
time, making these assumptions
conservative. We then include the
additional assumption that a person is
located at this point during this same
time period. For this source category,
these assumptions would tend to be
worst-case actual exposures as it is
unlikely that a person would be located
at the point of maximum exposure
during the time when peak emissions
and worst-case meteorological
conditions occur simultaneously.
d. Uncertainties in Dose-Response
Relationships
There are uncertainties inherent in
the development of the dose-response
values used in our risk assessments for
cancer effects from chronic exposures
and non-cancer effects from both
chronic and acute exposures. Some
uncertainties may be considered
quantitatively, and others generally are
expressed in qualitative terms. We note
as a preface to this discussion a point on
dose-response uncertainty that is
brought out in the EPA’s 2005 Cancer
Guidelines; namely, that ‘‘the primary
goal of EPA actions is protection of
human health; accordingly, as an
Agency policy, risk assessment
procedures, including default options
that are used in the absence of scientific
data to the contrary, should be health
protective’’ (EPA’s 2005 Cancer
Guidelines, pages 1–7). This is the
approach followed here as summarized
in the next several paragraphs. A
complete detailed discussion of
uncertainties and variability in doseresponse relationships is given in the
Residual Risk Assessment for the
Portland Cement Manufacturing
Industry Source Category in Support of
the Risk and Technology Review
September 2017 Proposed Rule, which
is available in the docket for this action.
Cancer URE values used in our risk
assessments are those that have been
developed to generally provide an upper
bound estimate of risk. That is, they
represent a ‘‘plausible upper limit to the
true value of a quantity’’ (although this
is usually not a true statistical
confidence limit).17 In some
circumstances, the true risk could be as
17 IRIS glossary (https://ofmpub.epa.gov/sor_
internet/registry/termreg/searchandretrieve/
glossariesandkeywordlists/search.do?details=
&glossaryName=IRIS%20Glossary).
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low as zero; however, in other
circumstances, the risk could be
greater.18 When developing an upper
bound estimate of risk and to provide
risk values that do not underestimate
risk, health-protective default
approaches are generally used. To err on
the side of ensuring adequate health
protection, the EPA typically uses the
upper bound estimates rather than
lower bound or central tendency
estimates in our risk assessments, an
approach that may have limitations for
other uses (e.g., priority-setting or
expected benefits analysis).
Chronic non-cancer RfC and reference
dose (RfD) values represent chronic
exposure levels that are intended to be
health-protective levels. Specifically,
these values provide an estimate (with
uncertainty spanning perhaps an order
of magnitude) of a continuous
inhalation exposure (RfC) or a daily oral
exposure (RfD) to the human population
(including sensitive subgroups) that is
likely to be without an appreciable risk
of deleterious effects during a lifetime.
To derive values that are intended to be
‘‘without appreciable risk,’’ the
methodology relies upon an uncertainty
factor (UF) approach (U.S. EPA, 1993
and 1994) which considers uncertainty,
variability, and gaps in the available
data. The UF are applied to derive
reference values that are intended to
protect against appreciable risk of
deleterious effects. The UF are
commonly default values,19 (e.g., factors
of 10 or 3), used in the absence of
compound-specific data; where data are
available, a UF may also be developed
using compound-specific information.
18 An exception to this is the URE for benzene,
which is considered to cover a range of values, each
end of which is considered to be equally plausible,
and which is based on maximum likelihood
estimates.
19 According to the NRC report, Science and
Judgment in Risk Assessment (NRC, 1994)
‘‘[Default] options are generic approaches, based on
general scientific knowledge and policy judgment,
that are applied to various elements of the risk
assessment process when the correct scientific
model is unknown or uncertain.’’ The 1983 NRC
report, Risk Assessment in the Federal Government:
Managing the Process, defined default option as
‘‘the option chosen on the basis of risk assessment
policy that appears to be the best choice in the
absence of data to the contrary’’ (NRC, 1983a, p. 63).
Therefore, default options are not rules that bind
the Agency; rather, the Agency may depart from
them in evaluating the risks posed by a specific
substance when it believes this to be appropriate.
In keeping with the EPA’s goal of protecting public
health and the environment, default assumptions
are used to ensure that risk to chemicals is not
underestimated (although defaults are not intended
to overtly overestimate risk). See EPA, An
Examination of EPA Risk Assessment Principles
and Practices, EPA/100/B–04/001, 2004, available
at https://nctc.fws.gov/resources/course-resources/
pesticides/Risk%20Assessment/Risk
%20Assessment%20Principles%20and
%20Practices.pdf.
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When data are limited, more
assumptions are needed and more UF
are used. Thus, there may be a greater
tendency to overestimate risk in the
sense that further study might support
development of reference values that are
higher (i.e., less potent) because fewer
default assumptions are needed.
However, for some pollutants, it is
possible that risks may be
underestimated.
While collectively termed ‘‘UF,’’ these
factors account for a number of different
quantitative considerations when using
observed animal (usually rodent) or
human toxicity data in the development
of the RfC. The UF are intended to
account for: (1) Variation in
susceptibility among the members of the
human population (i.e., inter-individual
variability); (2) uncertainty in
extrapolating from experimental animal
data to humans (i.e., interspecies
differences); (3) uncertainty in
extrapolating from data obtained in a
study with less-than-lifetime exposure
(i.e., extrapolating from sub-chronic to
chronic exposure); (4) uncertainty in
extrapolating the observed data to
obtain an estimate of the exposure
associated with no adverse effects; and
(5) uncertainty when the database is
incomplete or there are problems with
the applicability of available studies.
Many of the UF used to account for
variability and uncertainty in the
development of acute reference values
are quite similar to those developed for
chronic durations, but they more often
use individual UF values that may be
less than 10. The UF are applied based
on chemical-specific or health effectspecific information (e.g., simple
irritation effects do not vary appreciably
between human individuals, hence a
value of 3 is typically used), or based on
the purpose for the reference value (see
the following paragraph). The UF
applied in acute reference value
derivation include: (1) Heterogeneity
among humans; (2) uncertainty in
extrapolating from animals to humans;
(3) uncertainty in lowest observed
adverse effect (exposure) level to no
observed adverse effect (exposure) level
adjustments; and (4) uncertainty in
accounting for an incomplete database
on toxic effects of potential concern.
Additional adjustments are often
applied to account for uncertainty in
extrapolation from observations at one
exposure duration (e.g., 4 hours) to
derive an acute reference value at
another exposure duration (e.g., 1 hour).
Not all acute reference values are
developed for the same purpose, and
care must be taken when interpreting
the results of an acute assessment of
human health effects relative to the
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reference value or values being
exceeded. Where relevant to the
estimated exposures, the lack of shortterm dose-response values at different
levels of severity should be factored into
the risk characterization as potential
uncertainties.
Although every effort is made to
identify appropriate human health effect
dose-response assessment values for all
pollutants emitted by the sources in this
risk assessment, some HAP emitted by
this source category are lacking doseresponse assessments. Accordingly,
these pollutants cannot be included in
the quantitative risk assessment, which
could result in quantitative estimates
understating HAP risk. To help to
alleviate this potential underestimate,
where we conclude similarity with a
HAP for which a dose-response
assessment value is available, we use
that value as a surrogate for the
assessment of the HAP for which no
value is available. To the extent use of
surrogates indicates appreciable risk, we
may identify a need to increase priority
for new IRIS assessment of that
substance. We additionally note that,
generally speaking, HAP of greatest
concern due to environmental
exposures and hazard are those for
which dose-response assessments have
been performed, reducing the likelihood
of understating risk. Further, HAP not
included in the quantitative assessment
are assessed qualitatively and
considered in the risk characterization
that informs the risk management
decisions, including with regard to
consideration of HAP reductions
achieved by various control options.
For a group of compounds that are
unspeciated (e.g., glycol ethers), we
conservatively use the most protective
reference value of an individual
compound in that group to estimate
risk. Similarly, for an individual
compound in a group (e.g., ethylene
glycol diethyl ether) that does not have
a specified reference value, we also
apply the most protective reference
value from the other compounds in the
group to estimate risk.
e. Uncertainties in the Multipathway
Assessment
For each source category, we
generally rely on site-specific levels of
PB–HAP emissions to determine
whether a refined assessment of the
impacts from multipathway exposures
is necessary. This determination is
based on the results of a three-tiered
screening analysis that relies on the
outputs from models that estimate
environmental pollutant concentrations
and human exposures for five PB–HAP.
Two important types of uncertainty
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associated with the use of these models
in RTR risk assessments and inherent to
any assessment that relies on
environmental modeling are model
uncertainty and input uncertainty.20
Model uncertainty concerns whether
the selected models are appropriate for
the assessment being conducted and
whether they adequately represent the
actual processes that might occur for
that situation. An example of model
uncertainty is the question of whether
the model adequately describes the
movement of a pollutant through the
soil. This type of uncertainty is difficult
to quantify. However, based on feedback
received from previous EPA SAB
reviews and other reviews, we are
confident that the models used in the
screen are appropriate and state-of-theart for the multipathway risk
assessments conducted in support of
RTR.
Input uncertainty is concerned with
how accurately the models have been
configured and parameterized for the
assessment at hand. For Tier 1 of the
multipathway screen, we configured the
models to avoid underestimating
exposure and risk. This was
accomplished by selecting upper-end
values from nationally-representative
datasets for the more influential
parameters in the environmental model,
including selection and spatial
configuration of the area of interest, lake
location and size, meteorology, surface
water and soil characteristics, and
structure of the aquatic food web. We
also assume an ingestion exposure
scenario and values for human exposure
factors that represent reasonable
maximum exposures.
In Tier 2 of the multipathway
assessment, we refine the model inputs
to account for meteorological patterns in
the vicinity of the facility versus using
upper-end national values, and we
identify the actual location of lakes near
the facility rather than the default lake
location that we apply in Tier 1. By
refining the screening approach in Tier
2 to account for local geographical and
meteorological data, we decrease the
likelihood that concentrations in
environmental media are overestimated,
thereby increasing the usefulness of the
screen. The assumptions and the
associated uncertainties regarding the
selected ingestion exposure scenario are
the same for Tier 1 and Tier 2.
20 In the context of this discussion, the term
‘‘uncertainty’’ as it pertains to exposure and risk
encompasses both variability in the range of
expected inputs and screening results due to
existing spatial, temporal, and other factors, as well
as uncertainty in being able to accurately estimate
the true result.
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For both Tiers 1 and 2 of the
multipathway assessment, our approach
to addressing model input uncertainty is
generally cautious. We choose model
inputs from the upper end of the range
of possible values for the influential
parameters used in the models, and we
assume that the exposed individual
exhibits ingestion behavior that would
lead to a high total exposure. This
approach reduces the likelihood of not
identifying high risks for adverse
impacts.
Despite the uncertainties, when
individual pollutants or facilities do
screen out, we are confident that the
potential for adverse multipathway
impacts on human health is very low.
On the other hand, when individual
pollutants or facilities do not screen out,
it does not mean that multipathway
impacts are significant, only that we
cannot rule out that possibility and that
a refined multipathway analysis for the
site might be necessary to obtain a more
accurate risk characterization for the
source category. The site-specific
multipathway assessment improves
upon the screens by utilizing AERMOD
to estimate dispersion and deposition
impacts upon delineated watersheds
and farms. This refinement also
provides improved soil and water runoff calculations for effected watershed(s)
and adjacent parcels in estimating
media concentrations for each PB–HAP
modeled.
For further information on
uncertainties and the Tier 1 and 2
screening methods, refer to Appendix 5
of the risk report, ‘‘Technical Support
Document for TRIM-Based
Multipathway Tiered Screening
Methodology for RTR: Summary of
Approach and Evaluation.’’
f. Uncertainties in the Environmental
Risk Screening Assessment
For each source category, we
generally rely on site-specific levels of
environmental HAP emissions to
perform an environmental screening
assessment. The environmental
screening assessment is based on the
outputs from models that estimate
environmental HAP concentrations. The
TRIM.FaTE multipathway model and
the AERMOD air dispersion model, are
used to estimate environmental HAP
concentrations for the environmental
screening analysis. The human
multipathway screening analysis are
based upon the TRIM.FaTE model,
while the site-specific assessments
incorporate AERMOD model runs into
the TRIM.FaTE model runs. Therefore,
both screening assessments have similar
modeling uncertainties.
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Two important types of uncertainty
associated with the use of these models
in RTR environmental screening
assessments (and inherent to any
assessment that relies on environmental
modeling) are model uncertainty and
input uncertainty.21
Model uncertainty concerns whether
the selected models are appropriate for
the assessment being conducted and
whether they adequately represent the
movement and accumulation of
environmental HAP emissions in the
environment. For example, does the
model adequately describe the
movement of a pollutant through the
soil? This type of uncertainty is difficult
to quantify. However, based on feedback
received from previous EPA SAB
reviews and other reviews, we are
confident that the models used in the
screen are appropriate and state-of-theart for the environmental risk
assessments conducted in support of
our RTR analyses.
Input uncertainty is concerned with
how accurately the models have been
configured and parameterized for the
assessment at hand. For Tier 1 of the
environmental screen for PB–HAP, we
configured the models to avoid
underestimating exposure and risk to
reduce the likelihood that the results
indicate the risks are lower than they
actually are. This was accomplished by
selecting upper-end values from
nationally-representative datasets for
the more influential parameters in the
environmental model, including
selection and spatial configuration of
the area of interest, the location and size
of any bodies of water, meteorology,
surface water and soil characteristics,
and structure of the aquatic food web.
In Tier 1, we used the maximum
facility-specific emissions for the PB–
HAP (other than lead compounds,
which were evaluated by comparison to
the Secondary Lead NAAQS) that were
included in the environmental
screening assessment and each of the
media when comparing to ecological
benchmarks. This is consistent with the
conservative design of Tier 1 of the
screen. In Tier 2 of the environmental
screening analysis for PB–HAP, we
refine the model inputs to account for
meteorological patterns in the vicinity
of the facility versus using upper-end
national values, and we identify the
locations of water bodies near the
facility location. By refining the
21 In the context of this discussion, the term
‘‘uncertainty,’’ as it pertains to exposure and risk
assessment, encompasses both variability in the
range of expected inputs and screening results due
to existing spatial, temporal, and other factors, as
well as uncertainty in being able to accurately
estimate the true result.
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screening approach in Tier 2 to account
for local geographical and
meteorological data, we decrease the
likelihood that concentrations in
environmental media are overestimated,
thereby increasing the usefulness of the
screen. To better represent widespread
impacts, the modeled soil
concentrations are averaged in Tier 2 to
obtain one average soil concentration
value for each facility and for each PB–
HAP. For PB–HAP concentrations in
water, sediment, and fish tissue, the
highest value for each facility for each
pollutant is used.
For the environmental screening
assessment for acid gases, we employ a
single-tiered approach. We use the
modeled air concentrations and
compare those with ecological
benchmarks.
For both Tiers 1 and 2 of the
environmental screening assessment,
our approach to addressing model input
uncertainty is generally cautious. We
choose model inputs from the upper
end of the range of possible values for
the influential parameters used in the
models, and we assume that the
exposed individual exhibits ingestion
behavior that would lead to a high total
exposure. This approach reduces the
likelihood of not identifying potential
risks for adverse environmental impacts.
Uncertainty also exists in the
ecological benchmarks for the
environmental risk screening analysis.
We established a hierarchy of preferred
benchmark sources to allow selection of
benchmarks for each environmental
HAP at each ecological assessment
endpoint. In general, EPA benchmarks
used at a programmatic level (e.g.,
Office of Water, Superfund Program)
were used if available. If not, we used
EPA benchmarks used in regional
programs (e.g., Superfund Program). If
benchmarks were not available at a
programmatic or regional level, we used
benchmarks developed by other
agencies (e.g., NOAA) or by state
agencies.
In all cases (except for lead
compounds, which were evaluated
through a comparison to the NAAQS),
we searched for benchmarks at the
following three effect levels, as
described in section III.A.6 of this
preamble:
1. A no-effect level (i.e., NOAEL).
2. Threshold-effect level (i.e.,
LOAEL).
3. Probable effect level (i.e., PEL).
For some ecological assessment
endpoint/environmental HAP
combinations, we could identify
benchmarks for all three effect levels,
but for most, we could not. In one case,
where different agencies derived
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significantly different numbers to
represent a threshold for effect, we
included both. In several cases, only a
single benchmark was available. In
cases where multiple effect levels were
available for a particular PB–HAP and
assessment endpoint, we used all of the
available effect levels to help us to
determine whether risk exists and if the
risks could be considered significant
and widespread.
The EPA evaluates the following eight
HAP in the environmental risk
screening assessment: cadmium
compounds, D/F, arsenic compounds,
POM, mercury compounds (both
inorganic mercury and methyl mercury),
lead compounds, HCl, and HF, where
applicable. These eight HAP represent
pollutants that can cause adverse
impacts for plants and animals either
through direct exposure to HAP in the
air or through exposure to HAP that is
deposited from the air onto soils and
surface waters. These eight HAP also
represent those HAP for which we can
conduct a meaningful environmental
risk screening assessment. For other
HAP not included in our screening
assessment, the model has not been
parameterized such that it can be used
for that purpose. In some cases,
depending on the HAP, we may not
have appropriate multipathway models
that allow us to predict the
concentration of that pollutant. The EPA
acknowledges that other HAP beyond
the eight HAP that we are evaluating
may have the potential to cause adverse
environmental effects and, therefore, the
EPA may evaluate other relevant HAP in
the future, as modeling science and
resources allow.
Further information on uncertainties
and the Tier 1 and 2 environmental
screening methods is provided in
Appendix 5 of the document, Technical
Support Document for TRIM-Based
Multipathway Tiered Screening
Methodology for RTR: Summary of
Approach and Evaluation. Also, see the
Residual Risk Assessment for Portland
Cement Manufacturing Industry Source
Category in Support of the Risk and
Technology Review September 2017
Proposed Rule, available in the docket
for this action.
B. How did we consider the risk results
in making decisions for this proposal?
As discussed in section II.A of this
preamble, in evaluating and developing
standards under CAA section 112(f)(2),
we apply a two-step process to address
residual risk. In the first step, the EPA
determines whether risks are acceptable.
This determination ‘‘considers all health
information, including risk estimation
uncertainty, and includes a presumptive
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44271
limit on maximum individual lifetime
[cancer] risk (MIR) 22 of approximately
[1-in-10 thousand] [i.e., 100-in-1
million].’’ 54 FR 38045, September 14,
1989. If risks are unacceptable, the EPA
must determine the emission standards
necessary to bring risks to an acceptable
level without considering costs. In the
second step of the process, the EPA
considers whether the emissions
standards provide an ample margin of
safety ‘‘in consideration of all health
information, including the number of
persons at risk levels higher than
approximately 1-in-1 million, as well as
other relevant factors, including costs
and economic impacts, technological
feasibility, and other factors relevant to
each particular decision.’’ Id. The EPA
must promulgate emission standards
necessary to provide an ample margin of
safety. After conducting the ample
margin of safety analysis, we consider
whether a more stringent standard is
necessary to prevent, taking into
consideration, costs, energy, safety, and
other relevant factors, an adverse
environmental effect.
In past residual risk actions, the EPA
considered a number of human health
risk metrics associated with emissions
from the categories under review,
including the MIR, the number of
persons in various risk ranges, cancer
incidence, the maximum non-cancer HI
and the maximum acute non-cancer
hazard. See, e.g., 72 FR 25138, May 3,
2007; and 71 FR 42724, July 27, 2006.
The EPA considered this health
information for both actual and
allowable emissions. See, e.g., 75 FR
65068, October 21, 2010; 75 FR 80220,
December 21, 2010; 76 FR 29032, May
19, 2011. The EPA also discussed risk
estimation uncertainties and considered
the uncertainties in the determination of
acceptable risk and ample margin of
safety in these past actions. The EPA
considered this same type of
information in support of this action.
The Agency is considering these
various measures of health information
to inform our determinations of risk
acceptability and ample margin of safety
under CAA section 112(f). As explained
in the Benzene NESHAP, ‘‘the first step
judgment on acceptability cannot be
reduced to any single factor’’ and, thus,
‘‘[t]he Administrator believes that the
acceptability of risk under [previous]
section 112 is best judged on the basis
of a broad set of health risk measures
and information.’’ 54 FR 38046,
September 14, 1989. Similarly, with
22 Although defined as ‘‘maximum individual
risk,’’ MIR refers only to cancer risk. MIR, one
metric for assessing cancer risk, is the estimated
risk were an individual exposed to the maximum
level of a pollutant for a lifetime.
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regard to the ample margin of safety
determination, ‘‘the Agency again
considers all of the health risk and other
health information considered in the
first step. Beyond that information,
additional factors relating to the
appropriate level of control will also be
considered, including cost and
economic impacts of controls,
technological feasibility, uncertainties,
and any other relevant factors.’’ Id.
The Benzene NESHAP approach
provides flexibility regarding factors the
EPA may consider in making
determinations and how the EPA may
weigh those factors for each source
category. In responding to comment on
our policy under the Benzene NESHAP,
the EPA explained that:
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[t]he policy chosen by the Administrator
permits consideration of multiple measures
of health risk. Not only can the MIR figure
be considered, but also incidence, the
presence of non-cancer health effects, and the
uncertainties of the risk estimates. In this
way, the effect on the most exposed
individuals can be reviewed as well as the
impact on the general public. These factors
can then be weighed in each individual case.
This approach complies with the Vinyl
Chloride mandate that the Administrator
ascertain an acceptable level of risk to the
public by employing [her] expertise to assess
available data. It also complies with the
Congressional intent behind the CAA, which
did not exclude the use of any particular
measure of public health risk from the EPA’s
consideration with respect to CAA section
112 regulations, and thereby implicitly
permits consideration of any and all
measures of health risk which the
Administrator, in [her] judgment, believes are
appropriate to determining what will ‘protect
the public health’.
See 54 FR at 38057, September 14,
1989. Thus, the level of the MIR is only
one factor to be weighed in determining
acceptability of risks. The Benzene
NESHAP explained that ‘‘an MIR of
approximately one in 10 thousand
should ordinarily be the upper end of
the range of acceptability. As risks
increase above this benchmark, they
become presumptively less acceptable
under CAA section 112, and would be
weighed with the other health risk
measures and information in making an
overall judgment on acceptability. Or,
the Agency may find, in a particular
case, that a risk that includes MIR less
than the presumptively acceptable level
is unacceptable in the light of other
health risk factors.’’ Id. at 38045.
Similarly, with regard to the ample
margin of safety analysis, the EPA stated
in the Benzene NESHAP that: ‘‘EPA
believes the relative weight of the many
factors that can be considered in
selecting an ample margin of safety can
only be determined for each specific
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source category. This occurs mainly
because technological and economic
factors (along with the health-related
factors) vary from source category to
source category.’’ Id. at 38061. We also
consider the uncertainties associated
with the various risk analyses, as
discussed earlier in this preamble, in
our determinations of acceptability and
ample margin of safety.
The EPA notes that it has not
considered certain health information to
date in making residual risk
determinations. At this time, we do not
attempt to quantify those HAP risks that
may be associated with emissions from
other facilities that do not include the
source categories in question, mobile
source emissions, natural source
emissions, persistent environmental
pollution, or atmospheric
transformation in the vicinity of the
sources in these categories.
The Agency understands the potential
importance of considering an
individual’s total exposure to HAP in
addition to considering exposure to
HAP emissions from the source category
and facility. We recognize that such
consideration may be particularly
important when assessing non-cancer
risks, where pollutant-specific exposure
health reference levels (e.g., RfCs) are
based on the assumption that thresholds
exist for adverse health effects. For
example, the Agency recognizes that,
although exposures attributable to
emissions from a source category or
facility alone may not indicate the
potential for increased risk of adverse
non-cancer health effects in a
population, the exposures resulting
from emissions from the facility in
combination with emissions from all of
the other sources (e.g., other facilities) to
which an individual is exposed may be
sufficient to result in increased risk of
adverse non-cancer health effects. In
May 2010, the SAB advised the EPA
‘‘that RTR assessments will be most
useful to decision makers and
communities if results are presented in
the broader context of aggregate and
cumulative risks, including background
concentrations and contributions from
other sources in the area.’’ 23
In response to the SAB
recommendations, the EPA is
incorporating cumulative risk analyses
into its RTR risk assessments, including
23 The EPA’s responses to this and all other key
recommendations of the SAB’s advisory on RTR
risk assessment methodologies (which is available
at: https://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPASAB-10-007-unsigned.pdf) are outlined in a
memorandum to this rulemaking docket from David
Guinnup titled, EPA’s Actions in Response to the
Key Recommendations of the SAB Review of RTR
Risk Assessment Methodologies.
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those reflected in this proposal. The
Agency is: (1) Conducting facility-wide
assessments, which include source
category emission points, as well as
other emission points within the
facilities; (2) considering sources in the
same category whose emissions result in
exposures to the same individuals; and
(3) for some persistent and
bioaccumulative pollutants, analyzing
the ingestion route of exposure. In
addition, the RTR risk assessments have
always considered aggregate cancer risk
from all carcinogens and aggregate noncancer HI from all non-carcinogens
affecting the same target organ system.
Although we are interested in placing
source category and facility-wide HAP
risks in the context of total HAP risks
from all sources combined in the
vicinity of each source, we are
concerned about the uncertainties of
doing so. Because of the contribution to
total HAP risk from emission sources
other than those that we have studied in
depth during this RTR review, such
estimates of total HAP risks would have
significantly greater associated
uncertainties than the source category or
facility-wide estimates. Such aggregate
or cumulative assessments would
compound those uncertainties, making
the assessments too unreliable.
C. How did we perform the technology
review?
Our technology review focused on the
identification and evaluation of
developments in practices, processes,
and control technologies that have
occurred since the MACT standards
were promulgated. Where we identified
such developments, in order to inform
our decision of whether it is
‘‘necessary’’ to revise the emissions
standards, we analyzed the technical
feasibility of applying these
developments and the estimated costs,
energy implications, non-air
environmental impacts, as well as
considering the emission reductions.
We also considered the appropriateness
of applying controls to new sources
versus retrofitting existing sources.
Based on our analyses of the available
data and information, we identified
potential developments in practices,
processes, and control technologies. For
this exercise, we considered any of the
following to be a ‘‘development’’:
• Any add-on control technology or
other equipment that was not identified
and considered during development of
the original MACT standards;
• Any improvements in add-on
control technology or other equipment
(that were identified and considered
during development of the original
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MACT standards) that could result in
additional emissions reduction;
• Any work practice or operational
procedure that was not identified or
considered during development of the
original MACT standards;
• Any process change or pollution
prevention alternative that could be
broadly applied to the industry and that
was not identified or considered during
development of the original MACT
standards; and
• Any significant changes in the cost
(including cost effectiveness) of
applying controls (including controls
the EPA considered during the
development of the original MACT
standards).
In addition to reviewing the practices,
processes, and control technologies that
were considered at the time we
originally developed (or last updated)
the NESHAP, we reviewed a variety of
data sources in our investigation of
potential practices, processes, or
controls to consider. Among the sources
we reviewed were the NESHAP for
various industries that were
promulgated since the MACT standards
being reviewed in this action. We
reviewed the regulatory requirements
and/or technical analyses associated
with these regulatory actions to identify
any practices, processes, and control
technologies considered in these efforts
that could be applied to emission
sources in the Portland Cement
Manufacturing Industry source category,
as well as the costs, non-air impacts,
and energy implications associated with
the use of these technologies. Finally,
we reviewed information from other
sources, such as state and/or local
permitting agency databases and
industry-supported databases.
IV. Analytical Results and Proposed
Decisions
A. What are the results of the risk
assessment and analyses?
1. Inhalation Risk Assessment Results
Table 3 of this preamble provides an
overall summary of the inhalation risk
results. The results of the chronic
baseline inhalation cancer risk
assessment indicate that, based on
estimates of current actual and
44273
allowable emissions, the MIR posed by
the Portland Cement Manufacturing
Industry source category was estimated
to be 1-in-1 million and 4-in-1 million,
respectively, from volatile HAP being
emitted from the kilns. The total
estimated cancer incidence from
Portland Cement Manufacturing
Industry emission sources based on
actual emission levels is 0.01 excess
cancer cases per year, or one case in
every 100 years. The total estimated
cancer incidence from Portland Cement
Manufacturing Industry emission
sources based on allowable emission
levels is 0.03 excess cancer cases per
year, or one case in every 33 years.
Emissions of formaldehyde, benzene,
naphthalene, and acetaldehyde
contributed 91 percent to this cancer
incidence. The population exposed to
cancer risks greater than or equal to 1in-1 million considering actual
emissions was estimated to be
approximately 130; for allowable
emissions, approximately 2,300 people
were estimated to be exposed to cancer
risks greater than or equal to 1-in-1
million.
TABLE 3—INHALATION RISK ASSESSMENT SUMMARY FOR PORTLAND CEMENT MANUFACTURING INDUSTRY SOURCE
CATEGORY
Cancer MIR
(in-1 million)
Based on actual
emissions
Source Category ......
Whole Facility ...........
1 Cancer
Based on allowable
emissions
1 (formaldehyde,
benzene).
70 (arsenic and chromium VI).
4 (formaldehyde,
benzene).
..................................
Population
with risk of
1-in-1 million
or greater 1
Population
with risk of
10-in-1 million
or greater 1
0.01
130
0
0.02
20,000
690
Max chronic
noncancer HI
HI < 1 (Actuals and
Allowables).
HI = 1 (Actuals).
incidence and populations exposed are based upon actual emissions.
The maximum chronic noncancer HI
(TOSHI) values for the source category,
based on actual and allowable
emissions, were estimated to be 0.02
and 0.06, respectively, with
formaldehyde, acetaldehyde, and
hydrochloric acid driving the TOSHI
value.
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Cancer
incidence
(cases per
year) 1
2. Acute Risk Results
Worst-case acute HQs were calculated
for every HAP for which there is an
acute health benchmark using actual
emissions. The maximum acute
noncancer HQ value for the source
category was less than 1. Acute HQs are
based upon actual emissions.
3. Multipathway Risk Screening Results
Results of the worst-case Tier 1
screening analysis indicate that PB–
HAP emissions (based on estimates of
actual emissions) from 70 of the 91
facilities in the source category exceed
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the screening values for the
carcinogenic PB–HAP (D/F and arsenic)
and that PB–HAP emissions from 68 of
the 91 facilities exceed the screening
values for mercury, a noncarcinogenic
PB–HAP. Cadmium emissions were
below the Tier 1 emission noncancer
screening level for each facility based
upon the combined Farmer and Fisher
scenarios. For the PB–HAP and facilities
that did not screen out at Tier 1, we
conducted a Tier 2 screening analysis.
The Tier 2 screen replaces some of the
assumptions used in Tier 1 with sitespecific data, the location of fishable
lakes, and local wind direction and
speed. The Tier 2 screen continues to
rely on high-end assumptions about
consumption of local fish and locally
grown or raised foods (adult female
angler at 99th percentile consumption
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Fmt 4701
Sfmt 4702
for fish 24 for the Fisher Scenario and
90th percentile for consumption of
locally grown or raised foods 25) for the
Farmer Scenario and uses an
assumption that the same individual
consumes each of these foods in high
end quantities (i.e., that an individual
has high end ingestion rates for each
food). The result of this analysis was the
development of site-specific
concentrations of D/F, arsenic
compounds, and mercury compounds. It
is important to note that, even with the
inclusion of some site-specific
information in the Tier 2 analysis, the
multipathway screening analysis is still
24 Burger, J. 2002. Daily Consumption of Wild
Fish and Game: Exposures of High End
Recreationists. International Journal of
Environmental Health Research, 12:343–354.
25 U.S. EPA. Exposure Factors Handbook, 2011
Edition (Final). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R–09/052F,
2011.
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a very conservative, health-protective
assessment (e.g., upper-bound
consumption of local fish, locally
grown, and/or raised foods) and in all
likelihood will yield results that serve
as an upper-bound multipathway risk
associated with a facility.
Based on the Tier 2 screening
analysis, 45 facilities emit D/F and
arsenic that exceed the Tier 2 cancer
screening value. D/F emissions
exceeded the screening value by a factor
of as much as 100 for the fisher scenario
and by as much as 30 for the farmer
scenario. For arsenic, the facility with
the largest exceedance of the cancer
screening value had an exceedance of 10
times the Tier 1 emission rate level
resulting in a Tier 2 screening value less
than 1 for both the Fisher and Farmer
scenarios. For mercury, 24 facilities
emit mercury emissions above the
noncancer screening value, with at least
one facility exceeding the screening
value by a factor of 30 for the Fisher
scenario. When we considered the effect
multiple facilities within the source
category could have on common lake(s)
in the modeling domain, mercury
emissions exceeded the noncancer
screening value by a factor of 40.
For D/F, we conducted a Tier 3
multipathway screen for the facility
with the highest Tier 2 multipathway
cancer screen (a value of 100) for the
Fisher scenario. The next highest
facility had a Tier 2 cancer screen value
of 40. Tier 3 has three individual stages,
and we progressed through each of
those stages until either the facility’s
PB–HAP emissions did not exceed the
screening value or all three stages had
been completed. These stages included
lake, plume rise, and time-series
assessments. Based on this Tier 3
screening analysis, the MIR facility had
D/F emissions that exceeded the
screening value by a factor of 20 for the
Fisher scenario. Further details on the
Tier 3 screening analysis can be found
in Appendix 11 of Residual Risk
Assessment for the Portland Cement
Manufacturing Industry Source
Category in Support of the Risk and
Technology Review September 2017
Proposed Rule.’’
An exceedance of a screening value in
any of the tiers cannot be equated with
a risk value or a HQ (or HI). Rather, it
represents a high-end estimate of what
the risk or hazard may be. For example,
facility emissions exceeding the
screening value by a factor of 2 for a
non-carcinogen can be interpreted to
mean that we are confident that the HQ
would be lower than 2. Similarly,
facility emissions exceeding the
screening value by a factor of 20 for a
carcinogen means that we are confident
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that the risk is lower than 20-in-1
million. Our confidence comes from the
health-protective assumptions that are
in the screens: we choose inputs from
the upper end of the range of possible
values for the influential parameters
used in the screens; and we assume that
the exposed individual exhibits
ingestion behavior that would lead to a
high total exposure.
For mercury emissions, we conducted
a site-specific assessment. Analysis of
the facilities with the highest Tier 2
screen values helped identify the
location for the site-specific assessment
and the facilitie(s) to model with TRIM_
FaTE. We also considered the effect
multiple facilities within the source
category could have on common lake(s)
in the modeling domain. The selection
of the facility(s) for the site-specific
assessment also included evaluating the
number and location of lakes impacted,
watershed boundaries, and land-use
features around the target lakes, (i.e.,
elevation changes, topography, rivers).
The three facilities selected are
located in Midlothian, Texas. One of the
three facilities had the largest Tier 2
screen value, as well as the lake with
the highest aggregated noncancer screen
value for mercury with a lake size of
over 6,600 acres. These sites were
selected because of the Tier 2 mercury
screening results and based on the
feasibility, with respect to the modeling
framework, of obtaining parameter
values for the region surrounding the
facilities. We expect that the exposure
scenarios we assessed are among the
highest that might be encountered for
other facilities in this source category.
The refined site-specific
multipathway assessment, as in the
screening assessments, includes some
hypothetical elements, namely the
hypothetical human receptor (e.g., the
Fisher scenario which did not screen
out in the screening assessments). We
also included children in different age
ranges and adults with lifetime cancer
risks evaluated for carcinogens if they
did not pass the screening, and
noncancer hazards evaluated for
different age groups for other chemicals
that did not pass the screening. It is
important to note that even though the
multipathway assessment has been
conducted, no data exist to verify the
existence of the hypothetical human
receptor.
The Fisher scenario involves an
individual who regularly consumes fish
caught in freshwater lakes in the
vicinity of the source of interest over the
course of a 70-year lifetime. Since the
Fisher scenario did not pass the
screening, we evaluated risks and/or
hazards from the one lake that was
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fished in the screening assessment, with
the same adjustments to fish ingestion
rates as used in the screening according
to lake acreage and its assumed impact
on fish productivity. The refined
multipathway assessment produced an
HQ of 0.6 for mercury for the three
facilities assessed. This risk assessment
represents the maximum hazard for
mercury through fish consumption for
the source category and, with an HQ
less than 1, is below the level of concern
for exposure to emissions from these
sources.
In evaluating the potential for
multipathway effects from emissions of
lead, we compared modeled hourly lead
concentrations to the secondary NAAQS
for lead (0.15 mg/m3). The highest
hourly lead concentration, of 0.023 mg/
m3, is below the NAAQS for lead,
indicating a low potential for
multipathway impacts of concern due to
lead.
4. Environmental Risk Screening Results
As described in section III.A of this
preamble, we conducted an
environmental risk screening
assessment for the Portland Cement
Manufacturing Industry source category
for the following six pollutants: Mercury
(methyl mercury and mercuric
chloride), arsenic, cadmium, lead, D/F,
and HCl. In the Tier 1 screening analysis
for PB–HAP (other than lead, which was
evaluated differently), cadmium and
arsenic emissions had no exceedances
of any ecological benchmarks evaluated.
D/F and methyl mercury emissions had
Tier 1 exceedances for surface soil.
Divalent mercury emissions had Tier 1
exceedances for sediment and surface
soil. A Tier 2 screening analysis was
performed for D/F, divalent mercury,
and methyl mercury emissions. In the
Tier 2 screening analysis, D/F emissions
had no exceedances of any ecological
benchmarks evaluated. Divalent
mercury emissions from six facilities
exceeded the Tier 2 screen for a
threshold level sediment benchmark by
a maximum screening value of 2. The
divalent mercury probable-effects
benchmark for sediment was not
exceeded. Methyl mercury emissions
from two facilities exceeded the Tier 2
screen for a NOAEL surface soil
benchmark for avian ground
insectivores (woodcock) by a maximum
screening value of 2. Other surface soil
benchmarks for methyl mercury were
not exceeded. Given the low Tier 2
maximum screening values of 2 for
divalent mercury and methyl mercury,
and the fact that only the most
protective benchmarks were exceeded, a
Tier 3 environmental risk screen was
not conducted for this source category.
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For lead, we did not estimate any
exceedances of the secondary lead
NAAQS. For HCl, the average modeled
concentration around each facility (i.e.,
the average concentration of all off-site
data points in the modeling domain) did
not exceed any ecological benchmark. In
addition, each individual modeled
concentration of HCl (i.e., each off-site
data point in the modeling domain) was
below the ecological benchmarks for all
facilities. Based on the results of the
environmental risk screening analysis,
we do not expect an adverse
environmental effect as a result of HAP
emissions from this source category.
5. Facility-Wide Risk Results
Results of the assessment of facilitywide emissions indicate that, of the 91
facilities, 16 facilities have a facilitywide cancer risk greater than or equal to
1-in-1 million (refer to Table 3). The
maximum facility-wide cancer risk is
70-in-1 million, mainly driven by
arsenic and chromium (VI) emissions
from construction activities involving
the hauling of sand and gravel from the
stone quarrying process. The next
highest facility-wide cancer risk is 8-in1 million.
The total estimated cancer incidence
from the whole facility is 0.02 excess
cancer cases per year, or one case in
every 50 years. Approximately 20,000
people are estimated to have cancer
risks greater than or equal to 1-in-1
million from exposure to whole facility
emissions from 16 facilities in the
source category. Approximately 700
people are estimated to have cancer risk
greater than 10-in-1 million from
exposure to whole facility emissions
from one facility in the source category.
The maximum facility-wide chronic
non-cancer TOSHI is estimated to be
equal to 1, mainly driven by emissions
of HCl from a drying operation routed
through the long kiln.
6. What demographic groups might
benefit from this regulation?
To examine the potential for any
environmental justice issues that might
44275
be associated with the source category,
we performed a demographic analysis of
the population close to the facilities. In
this analysis, we evaluated the
distribution of HAP-related cancer and
non-cancer risks from the Portland
Cement Manufacturing Industry source
category across different demographic
groups within the populations living
near facilities identified as having the
highest risks. The methodology and the
results of the demographic analyses are
included in a technical report, Risk and
Technology Review—Analysis of
Demographic Factors for Populations
Living Near Portland Cement
Manufacturing Facilities, available in
the docket for this action.
The results of the demographic
analysis are summarized in Table 4
below. These results, for various
demographic groups, are based on the
estimated risks from actual emission
levels for the population living within
50 km of the facilities.
TABLE 4—PORTLAND CEMENT MANUFACTURING INDUSTRY SOURCE CATEGORY DEMOGRAPHIC RISK ANALYSIS RESULTS
Population with
cancer risk at or
above 1-in-1
million due to
Portland Cement
Manufacturing
Nationwide
Total Population .........................................................................................................
Population with
chronic hazard
index above 1 due
to Portland
Cement
Manufacturing
317,746,049
134
0
62
38
71
29
0
0
62
12
0.8
7
94
1
1.6
3
0
0
0
0
18
82
24
76
0
0
14
86
10
90
0
0
14
86
11
89
0
0
Race by Percent
White ..........................................................................................................................
All Other Races .........................................................................................................
Race by Percent
White ..........................................................................................................................
African American .......................................................................................................
Native American ........................................................................................................
Other and Multiracial .................................................................................................
Ethnicity by Percent
Hispanic .....................................................................................................................
Non-Hispanic .............................................................................................................
Income by Percent
Below Poverty Level ..................................................................................................
Above Poverty Level ..................................................................................................
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Education by Percent
Over 25 and without High School Diploma ...............................................................
Over 25 and with a High School Diploma .................................................................
The results of the Portland Cement
Manufacturing Industry source category
demographic analysis indicate that
emissions from the source category
expose approximately 130 people to a
cancer risk at or above 1-in-1 million
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and no people to a chronic noncancer
TOSHI greater than 1. The percentages
of the at-risk population in each
demographic group (except for White,
Native American, and Hispanic) are
similar to or lower than their respective
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nationwide percentages. The specific
demographic results indicate that the
percentage of the population potentially
impacted by Portland cement emissions
is greater than its corresponding
nationwide percentage for the following
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demographics: Native American (1.6
percent compared to 0.8 percent
nationally), Hispanic or Latino (24
percent compared to 18 percent
nationally) and children aged 0 to 17 (32
percent compared to 23 percent
nationally). The other demographic
groups within the exposed population
were the same or lower than the
corresponding nationwide percentages.
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B. What are our proposed decisions
regarding risk acceptability, ample
margin of safety, and adverse
environmental effects?
1. Risk Acceptability
As noted in section II.A.1 of this
preamble, 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 maximum
individual lifetime [cancer] risk (MIR) 26
of approximately 1-in-10 thousand [i.e.,
100-in-1 million].’’ 54 FR 38045,
September 14, 1989. In this proposal,
we estimated risks based on actual and
allowable emissions. As discussed
earlier, we consider our analysis of risk
from allowable emissions to be
conservative and, as such, to represent
an upper bound estimate of inhalation
risk from emissions allowed under the
NESHAP for the source category.
The inhalation cancer risk to the
individual most exposed to emissions
from sources in the Portland Cement
Manufacturing Industry source category
is 1-in-1 million based on actual
emissions. The estimated incidence of
cancer due to inhalation exposure is
0.01 excess cancer cases per year, or one
case in every 100 years, based on actual
emissions. Approximately 130 people
are exposed to actual emissions
resulting in an increased cancer risk
greater than or equal to 1-in-1 million.
We estimate that, for allowable
emissions, the inhalation cancer risk to
the individual most exposed to
emissions from sources in this source
category is up to 4-in-1 million. The
estimated incidence of cancer due to
inhalation exposure is 0.02 excess
cancer cases per year, or one case in
every 50 years, based on allowable
emissions. Based on allowable
emissions, approximately 20,000 people
could be exposed to emissions resulting
in an increased cancer risk of up to 126 Although defined as ‘‘maximum individual
risk,’’ MIR refers only to cancer risk. MIR, one
metric for assessing cancer risk, is the estimated
risk were an individual exposed to the maximum
level of a pollutant for a lifetime.
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in-1 million, and about 690 people to an
increased cancer risk of up to 10-in-1
million.
The Agency estimates that the
maximum chronic noncancer TOSHI
from inhalation exposure is less than 1
due to actual emissions, and up to 1 due
to allowable emissions. The screening
assessment of worst-case acute
inhalation impacts from worst-case 1hour emissions indicates that no HAP
exceed an HQ value of 1.
Based on the results of the
multipathway cancer screening analyses
of arsenic and dioxin emissions, we
conclude that the cancer risk from
ingestion exposure to the individual
most exposed is less than 1-in-1 million
for arsenic and, based on a Tier 3
analysis, less than 20-in-1 million for
dioxins. Based on the Tier 1
multipathway screening analysis of
cadmium emissions and the refined sitespecific multipathway analysis of
mercury emissions, the maximum
chronic noncancer TOSHI due to
inhalation exposures is less than 1 for
actual emissions.
In determining whether risk is
acceptable, the EPA considered all
available health information and risk
estimation uncertainty, as described
above. The results indicate that both the
actual and allowable inhalation cancer
risks to the individual most exposed are
significantly less than 100-in-1 million,
which is the presumptive limit of
acceptability. The maximum chronic
noncancer TOSHI due to inhalation
exposures is less than 1 due to actual
emissions and up to 1 due to allowable
emissions, and our refined
multipathway analysis indicates that
noncancer ingestion risks also are less
than 1. Finally, the evaluation of acute
noncancer risks was very conservative
and showed that acute risks are below
a level of concern.
Taking into account this information,
we propose that the risk remaining after
implementation of the existing MACT
standards for the Portland Cement
Manufacturing Industry is acceptable.
2. Ample Margin of Safety Analysis
Although we are proposing that the
risks from the Portland Cement
Manufacturing Industry source category
are acceptable, for allowable emissions,
the inhalation cancer risk to the
individual most exposed to emissions
from sources in this source category is
up to 4-in-1 million, with approximately
2,000 individuals estimated to be
exposed to emissions resulting in an
increased cancer risk of 1-in-1 million
or greater. In addition, based on the Tier
3 multipathway screening analysis,
dioxin emissions from the MIR facility
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could pose a risk of up to 20-in-1
million. Thus, we considered whether
the existing MACT standards provide an
ample margin of safety to protect public
health. In addition to considering all of
the health risks and other health
information considered in the risk
acceptability determination, in the
ample margin of safety analysis, we
evaluated the cost and feasibility of
available control technologies and other
measures (including the controls,
measures, and costs reviewed under the
technology review) that could be
applied in this source category to
further reduce the risks due to
emissions of HAP.
Our inhalation risk analysis indicates
very low potential for risk from the
facilities in the source category based
upon actual emissions at 1-in-1 million,
and just slightly higher risks based upon
allowable emissions at 4-in-1 million.
Therefore, very little reduction in
inhalation risks could be realized
regardless of the availability of control
options. As directed by CAA section
112(f)(2), we conducted an analysis to
determine if the standard provides an
ample margin of safety to protect public
health. The HAP risk drivers
contributing to the inhalation MIR in
excess of 1-in-1 million for 40 CFR part
63, subpart LLL facilities include
primarily the gaseous organic HAP:
Formaldehyde, benzene, naphthalene,
and acetaldehyde. More than 62 percent
of the mass emissions of these
compounds originate from kiln
operations.
The following paragraphs provide our
analyses of HAP-reducing measures that
we considered in our ample margin of
safety analysis. For each option, we
considered feasibility, costeffectiveness, and health information in
determining whether to revise standards
in order to provide an ample margin of
safety.
The first technology we evaluated in
our ample margin of safety analysis is a
regenerative thermal oxidizer (RTO). To
assess the costs associated with RTOs,
we relied on our beyond-the-floor (BTF)
analysis documented in the May 6,
2009, Portland Cement NESHAP
proposal (74 FR 21136). In that
proposal, we assessed the potential for
further reductions in THC and organic
HAP emissions beyond the reductions
achieved by activated carbon injection
(ACI) (controlling mercury and THC
emissions), the typical kiln controls
used in the industry. To achieve further
reductions in THC, a kiln would likely
require additional controls, such as
RTO. It was expected that RTO would
only offer an additional 50-percent
removal efficiency, due to the reduced
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THC concentration leaving the ACI
control device and entering the
proposed RTO. The analysis indicates
that addition of an RTO would reduce
THC emissions by approximately 9 tpy,
for a cost effectiveness of $411,000/ton.
The HAP fraction would be
approximately 24 percent of THC, so 2
tpy of organic HAP would be removed,
at a cost effectiveness of $1.7 million/
ton of organic HAP. The details of this
analysis are included in 74 FR 21152–
21153. Overall, we do not consider the
use of an RTO to be cost effective for
this industry, and given the small
reduction in organic HAP emissions, the
addition of an RTO would have little
effect on the source category risks.
Exposure to dioxin emissions from
the MIR facility were found to pose a
non-inhalation MIR of less than 20-in-1
million, and possibly greater than 1-in1 million. Technologies evaluated
included the use of ACI with wet
scrubbers to help control D/F emissions.
For the March 24, 1998, proposal (63 FR
14182), we performed a BTF analysis
that considered the MACT floor for D/
F emissions controls to be a reduction
of the kiln exhaust gas stream
temperature at the PM control device
inlet to 400 degrees Fahrenheit (63 FR
14200). An ACI system was considered
as a potential BTF option. Total annual
costs were estimated to be $426,000 to
$3.3 million per kiln. The Agency
determined that, based on the additional
costs and the level of D/F emissions
reduction achievable, the BTF costs
were not justified (63 FR 14199–14201).
We do not consider the use of ACI
system to be cost effective for the
industry to use to reduce D/F emissions,
and would have little effect on the
source category risks.
Our multipathway screening analysis
results did not necessarily indicate any
risks from mercury emissions, but we
have also performed an evaluation of
mercury emissions controls. In the May
6, 2009, BTF analysis, it was estimated
for a typical 1.2 million tpy kiln, the
addition of a halogenated carbon
injection system would result in a 3.0
lb/year reduction in mercury at a cost of
$1.25 million/year and a cost
effectiveness of $420,000/lb of mercury
removed. If the halogenated carbon
injection system effectiveness is
reduced due to a low level of mercury
entering the system, 2.3 lb/year of
mercury would be removed at a cost
effectiveness of $540,000/lb of mercury
removed (74 FR 21149). We do not
consider the use of halogenated carbon
injection system to be cost effective for
the industry to use to reduce mercury
emissions, and would have little effect
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on the low risks identified for this
source category.
The cost-effectiveness values for
further reduction of organic HAP, as
referenced herein, are significantly
higher than values in other NESHAP we
have historically rejected for not being
cost effective for organic HAP. As
examples of determinations made
historically, refer to the National
Emission Standards for Hazardous Air
Pollutants Residual Risk and
Technology Review for Flexible
Polyurethane Foam Production (August
15, 2014, 79 FR 48078), the National
Emission Standards for Hazardous Air
Pollutant Emissions: Group I Polymers
and Resins (April 21, 2011, 77 FR
22579), and the National Emission
Standards for Organic Hazardous Air
Pollutants from the Synthetic Organic
Chemical Manufacturing Industry
(December 21, 2006, 71 FR 76605). We
also determined that further reduction
of dioxin emissions would not be cost
effective. Due to the low level of current
risk, the minimal risk reductions that
could be achieved with the various
control options that we evaluated, and
the substantial costs associated with
additional control options, we are
proposing that the current standards
provide an ample margin of safety.
3. Adverse Environmental Effects
Based on the results of our
environmental risk screening
assessment, we conclude that there is
not an adverse environmental effect
from the Portland Cement
Manufacturing Industry source category.
We are proposing that it is not necessary
to set a more stringent standard to
prevent, taking into consideration costs,
energy, safety, and other relevant
factors, an adverse environmental effect.
C. What are the results and proposed
decisions based on our technology
review?
Control devices typically used to
minimize emissions at Portland cement
manufacturing industry facilities
include fabric filters and electrostatic
precipitators (ESP) for control of PM
from kilns; fabric filters for the control
of PM from clinker coolers and raw
material handling operations; wet
scrubbers or dry lime injection for
control of HCl, and ACI, wet scrubbers,
or both for the control of mercury, D/F,
and THC. At least one kiln has
controlled THC using a wet scrubber
followed by an RTO. Process changes
used at some facilities to reduce HAP
emissions include dust shuttling to
reduce mercury emissions and raw
material substitution to reduce organic
HAP emissions. The add-on controls
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44277
and process changes used by a facility
to comply with the 40 CFR part 63,
subpart LLL emission standards are
highly site specific because of factors
such as variations in the HAP content of
raw materials and fuels, availability of
alternative raw materials and fuels, and
kiln characteristics (such as age and
type of kiln). In addition, new or
reconstructed kilns must also comply
with the New Source Performance
Standards (NSPS) for Cement
Manufacturing (40 CFR part 60, subpart
F). The NSPS sets limits for emissions
of PM, nitrogen oxides (NOX) and sulfur
dioxide (SO2). The PM limits in the
NSPS and the subpart LLL PM limits for
new sources are the same. Measures
taken at a facility to comply with the
NOX and SO2 limits must be considered
in light of the subpart LLL emission
standards. Due to the relatively recent
finalization of the MACT rules for
Portland cement manufacturing, there
have been no new developments in
practices, processes, or control
technologies that have been
implemented in this source category
since promulgation of the current
NESHAP. Nevertheless, we did review
several technologies that have been
available, or may be available soon, to
the industry and provided additional
options to the industry for reducing
HAP emissions. Based on information
available to the EPA, these technologies
do not clearly reduce HAP emissions
relative to technologies that were
considered by the EPA when
promulgating the Portland Cement
Manufacturing Industry NESHAP in
2013.
Selective catalytic reduction (SCR) is
the process of adding ammonia or urea
in the presence of a catalyst to
selectively reduce NOX emissions from
exhaust gases. A benefit of SCR may be
its ability to facilitate the removal of
mercury and other HAP emissions from
the Portland cement manufacturing
process. The EPA considered SCR in
proposing standards for NOX in 2008,
but did not propose SCR as best
demonstrated technology for several
reasons (73 FR 34072, June 16, 2008). At
the time of the proposal, SCR was in use
at just a few kilns in Europe, and no
cement kilns in the U.S. used SCR.
There were concerns over the plugging
of the SCR catalyst in high-dust
installations and, in low-dust
installations where the catalyst is
located downstream of the PM control
device, the cost of reheating cooled
exhaust was very high leading to
uncertainties over what actual costs
would be. Finally, SCR was anticipated
to increase energy use due to the
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pressure drop across the catalyst and
produce additional liquid and solid
waste to be handled.
Since then, SCR has been installed on
two cement kilns in the U.S. The two
installations in the U.S. started
operation in 2016 (Holcim in
Midlothian, Texas) and 2013 (Lafarge in
Joppa, Illinois). Holcim controls THC
through addition of SCR to Kiln 1 and
an RTO to Kiln 2. The SCR system at
Lafarge controls NOX and operates with
a long dry kiln with a hot ESP, and no
reheat.
Beyond its ability to reduce NOX by
90 percent, multipollutant benefits have
been reported. At kilns in Europe,
reductions in THC of 50 to greater than
70 percent have been reported.
Although D/F reductions have been
observed for SCR in many industries
and reductions in D/F have been
reported for an SCR installation at a
cement kiln in Italy, tests of D/F
reduction across SCR catalyst in the
Portland Cement Manufacturing
Industry have not been conducted. SCR
does not directly reduce mercury
emissions. Instead, SCR results in the
oxidation of mercury from its elemental
form, and the oxidized form is more
easily captured in scrubbers. The
addition of an SCR as control is
expected to have little impact on
reducing mercury emissions from
cement kilns without requiring the
addition of a scrubber system.
Catalytic ceramic filter candles and
catalytic filter bags are used to remove
not only particulate, but may be used to
remove other pollutants such as D/F,
THC, non-D/F organic HAP, carbon
monoxide (CO), and NOX. Catalytic
ceramic filter candles are typically
approximately 10 feet long. The length
is limited to 10 feet by several
considerations, including the weight of
the candle and the fact that the candle
cannot be flexed, limiting the height
above the seal plate. In contrast, the
length of catalytic filter bags can vary
from 10 to 32 feet. Currently, filter bags
at cement manufacturing facilities are
much longer than 10 feet. Therefore,
installing ceramic filter candles can
only be done by replacing the baghouse
housing (i.e., ceramic filter candles are
not a drop-in replacement for existing
filter bags).
FLSmidth received the first contract
for removal of THC with ceramic
catalytic filters at a U.S. cement kiln.
They noted that the removal of THC
with their ceramic catalytic filter system
depends on the speciation of THC
components, but that removal
efficiencies of greater than 90 percent
have been seen in testing for HAP THC
pollutants. Tri-Mer Corp., a technology
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company specializing in advanced
industrial air pollution control systems,
claims to have fully commercialized a
ceramic filter technology that is highly
effective for emissions from cement
kilns and other processes facing
NESHAP and MACT compliance issues.
Although no studies were identified in
the literature documenting the
performance of Tri-Mer’s ceramic filter
system, the company states that their
catalyst filter system is highly efficient
at removing PM, SO2, HCl, mercury, and
heavy metals, while simultaneously
destroying NOX, cement organic HAP
and D/F. Tri-Mer reports NOX removal
at up to 95 percent and D/F removal
typically over 97 percent. The system
can incorporate dry sorbent injection of
hydrated lime, sodium bicarbonate, or
trona for dry scrubbing of SO2, HCI, HF,
and other acid gases. With dry sorbent
injection, typical SO2 and HCl results
show 90- to 98-percent removal.
According to company information, the
control of any combination of these
pollutants is accomplished in a single,
completely dry system that is suitable
for all flow volumes.
Powdered activated carbon (PAC) for
mercury control was first used in the
U.S. for the incinerator (waste-toenergy) industry. Conventional PAC was
expected to be used for mercury control
for electrical power generation.
However, conventional PAC mercury
removal performance suffers in
situations involving high-sulfur coal,
which leads to high sulfur trioxide (SO3)
levels, or situations where SO3 is
injected to improve ESP performance. In
addition, a September 2007 test
conducted at the Ash Grove facility in
Durkee, Oregon, suggests that halogentreated PAC makes no difference in
controlling mercury emissions from a
kiln. Specifically, the report states,
‘‘While studies at coal-fired power
plants have indicated that the use of
halogen-treated PAC can result in higher
Hg control efficiencies, testing on the
Durkee exhaust gas indicated that
untreated carbon provides equivalent
control to halogen-treated carbon. This
is believed to be due to the low sulfur
levels in the Durkee cement kiln
exhaust gases as compared to coal-fired
power plants.’’ 27 We believe that, based
on our review, the addition of
halogenated PAC controls to further
reduce mercury emissions do not result
in a substantial reduction of mercury
emissions beyond current controls.
The Ash Grove facility in Durkee,
Oregon, had the highest mercury
27 Mercury Control Slipstream Baghouse Testing
at Ash Grove’s Durkee Cement Facility, September
2007.
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emissions of any Portland cement
manufacturing facility prior to
promulgation of the cement NESHAP.
To reach the NESHAP limit of 55 lbs
mercury per million tons of clinker, Ash
Grove installed a $20 million system for
mercury capture. It consists of a
baghouse with ACI. Dust collected in
the baghouse is sent to an electric
furnace where it is heated to 800
degrees Fahrenheit, which puts the
mercury back into a gaseous state. The
gaseous mercury moves into a cooling
chamber where it is converted into
liquid that is captured in a heat
exchanger/condenser. The liquid
mercury is then sold for use in
electronic devices and other products.
Praxair has developed a technology of
feeding a stream of hot oxygen into a
cement kiln to lower emissions of CO
and hydrocarbons. This technology
involves oxidation of CO at the kiln
inlet with oxygen enhanced
combustion, and has been in
commercial practice since 2014 at a kiln
in Europe. It has not been installed on
any cement kiln in the U.S. Oxygen is
injected in the riser with the goal of
lowering NOX and CO emissions to
below permitted levels of 230
milligrams per normal cubic meter (mg/
Nm3) and 4,000 mg/Nm3, respectively,
without use of a more expensive SCR
system.
As discussed before, there are several
technologies that can be effective in
reducing emission from the cement kiln.
However, most of these technologies
have not been widely used in the
industry so source category specific data
on their long term performance and
costs are lacking. Their performance is
typically similar to technologies already
employed or, in some cases, only
marginally better. In the case of SCR, it
had been noted that this might be an
alternative to current THC controls.
However, we note that SCR is most
effective on non-dioxin organic HAP
and is not effective on other
hydrocarbons. The organic HAP portion
of the 24 parts per million by volume
THC limit is typically low and is near
the actual detection limits for
measurement. Therefore, even if SCR
were more widely applied in the
industry, the emissions impact on THC
and organic HAP would be small.
D. What other actions are we proposing?
In addition to the proposed actions
described above, we are proposing
additional revisions, which include
changes to clarify monitoring, testing,
and recordkeeping and reporting
requirements and the correction of
typographical errors. Our analyses and
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Federal Register / Vol. 82, No. 182 / Thursday, September 21, 2017 / Proposed Rules
proposed changes related to these issues
are discussed below.
We are proposing to correct a
paragraph in the reporting requirements
that mistakenly requires that affected
sources report their 30-operating day
rolling average for D/F temperature
monitoring. There are no 30-day
operating rolling average temperature
requirements pertaining to D/F in the
rule. The removal of the reference to the
D/F temperature monitoring system in
40 CFR 63.1354(b)(9)(vi) is also
consistent with the EPA’s October 2016
rule guidance for the subpart LLL
NESHAP. See NESHAP for the Portland
Cement Manufacturing Industry Subpart
LLL Rule Guidance, which has been
updated to include revisions from this
proposed rule. (https://www.epa.gov/
sites/production/files/2016-03/
documents/ruleguidance_mar2016.pdf.)
We are proposing to correct a
provision that requires facility owners
or operators to keep records of both
daily clinker production and kiln feed
rates. Section 63.1350(d)(1)(ii) requires
daily kiln feed rate records only if the
facility derives their clinker production
rates from the measured feed rate.
The EPA is proposing to clarify that
the submittal dates for semiannual
summary reports required under 40 CFR
63.1354(b)(9) are 60 days after the end
of the reporting period consistent with
the Agency’s statement in the October
2016 rule guidance for the subpart LLL
NESHAP. In addition, the October 2016
rule guidance was revised in September
2017 to ensure it reflects the various
changes proposed in this rule.
The EPA is proposing to resolve
conflicting provisions that apply when
an SO2 continuous parametric
monitoring system is used to monitor
HCl compliance. If the SO2 level
exceeds by 10 percent or more the sitespecific SO2 emissions limit, 40 CFR
63.1349(b)(x) requires that as soon as
possible, but within 30 days, a facility
must take corrective action, and within
90 days, conduct a performance test to
demonstrate compliance with the HCl
limit and verify or re-establish the sitespecific SO2 emissions limit. These
conflict with 40 CFR 63.1350(l)(3),
which requires corrective action within
48 hours and retesting within 60 days.
We are proposing to adopt the
requirements of 40 CFR 63.1349(b)(x)
and change the requirement of 40 CFR
63.1350(l)(3) to reflect this.
We are proposing to clarify the
requirement in section 63.1349(b)(1)(vi)
which states that for each PM
performance test, an owner or operator
must conduct at least three separate test
runs each while the mill is on and the
mill is off. We are proposing that this
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provision only applies to kilns with
inline raw mills, as inline raw mills are
considered part of the kiln and can
affect kiln PM emissions. It specifically
would not apply to a kiln that does not
have an inline raw mill or to a clinker
cooler (unless the clinker cooler gases
are combined with kiln exhaust and
sent through an inline mill). As in these
cases, the raw mill is a separate source
from the kiln and has no effect on kiln
or clinker cooler PM emissions.
We are proposing changes which
affect the emission limits for D/F. Table
1 of 40 CFR 63.1343(b) lists the
emission limits for D/F. The units of the
emission limit are ng/dscm TEQ at 7percent oxygen. The TEQ is developed
by determining the mass of each
congener measured during the
performance test, then multiplying each
congener by the toxic equivalency factor
(TEF). After the TEQ is developed per
congener, they are added to obtain the
total TEQs. The TEFs were re-evaluated
in 2005 by the World Health
Organization—International Programme
on Chemical Safety using a different
scale of magnitude.28 The 40 CFR part
63, subpart LLL standards were
developed based on TEFs developed in
1989, as referenced in the TEQ
definition section of the rule (40 CFR
63.1341). Laboratories calculating the
TEQs should be using the TEFs
developed in 1989. We are proposing
that the 1989 TEFs be incorporated into
the rule to clarify that they are the
appropriate factors for calculating TEQ.
Finally, we are proposing to clarify
the performance test requirements for
certain sources. According to a
stakeholder, compliance with 40 CFR
part 63, subpart LLL is required
immediately upon startup and does not
allow companies an operating window
after periods of extended shutdown in
order to assess compliance. The
stakeholder states that extended
shutdowns of existing kilns occur in the
Portland cement manufacturing
industry in the aftermath of economic
downturns when companies have halted
production at certain facilities. When
the economy rebounds and sources are
brought back on line, they must
immediately comply with NESHAP and
other CAA requirements for existing
facilities. The stakeholder asserts that
this mandatory compliance requirement
does not account for the fact that owners
or operators must start the facilities back
up and run them for periods of time to
determine whether any measures must
28 Van den Berg, Martin, et al. The 2005 World
Health Organization Re-evaluation of Human and
Mammalian Toxic Equivalency Factors for Dioxins
and Dioxin-like Compounds. Toxicol. Sci. 2006,
October 1993(2): 223–241.
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be taken to come into compliance with
updated NESHAP or other standards. In
response, we are proposing to clarify the
performance test requirements for
affected sources that have been idle
through one or more periods that
required a performance test to
demonstrate compliance. The proposed
amendment would require any affected
source that was unable to demonstrate
compliance before the compliance date
due to being idled, or that had
demonstrated compliance, but was idled
during the normal window for the next
compliance test, to demonstrate
compliance with the emissions
standards and operating limits by
conducting their performance using the
test methods and procedures in 40 CFR
63.1349 and 63.7. Per 40 CFR 63.7, the
necessary performance tests would need
to be completed within 180 days of the
date that compliance must be
demonstrated.
E. What compliance dates are we
proposing?
Because these amendments only
provide corrections and clarifications to
the current rule and do not impose new
requirements on the industry, we are
proposing that these amendments
become effective upon promulgation of
the final rule.
V. Summary of Cost, Environmental,
and Economic Impacts
A. What are the impacts to affected
sources?
The recent amendments to the
Portland Cement Manufacturing
NESHAP have included rule updates,
addressing electronic reporting
requirements, and changes in policies
regarding startup, shutdown, and
malfunction. Because we are proposing
no new requirements or controls in this
RTR, no Portland cement manufacturing
facilities are adversely impacted by
these proposed revisions. In fact, the
impacts to the Portland cement
manufacturing industry from this
proposal will be minimal and
potentially positive.
B. What are the air quality impacts?
In this proposal, we recommend no
new emission limits and require no
additional controls; therefore, no air
quality impacts are expected as a result
of the proposed amendments.
C. What are the cost impacts?
As previously stated, recent
amendments to the Portland Cement
Manufacturing NESHAP have addressed
electronic reporting and changes in
policies regarding startup, shutdown,
and malfunction. Additionally, the
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proposed amendments recommend no
changes to emission standards or add-on
controls. Therefore, the proposed
amendments impose no additional
costs. In fact, the clarifications to rule
language may actually result in a
reduction of current costs because
compliance will be more
straightforward.
D. What are the economic impacts?
No economic impacts are expected as
a result of the proposed amendments.
E. What are the benefits?
While the proposed amendments
would not result in reductions in
emissions of HAP, this action, if
finalized, would result in improved
monitoring, compliance, and
implementation of the rule.
asabaliauskas on DSKBBXCHB2PROD with PROPOSALS
VI. Request for Comments
We solicit comments on all aspects of
this proposed action. In addition to
general comments on this proposed
action, we are also interested in
additional data that may improve the
risk assessments and other analyses. We
are specifically interested in receiving
any improvements to the data used in
the site-specific emissions profiles used
for risk modeling. Such data should
include supporting documentation in
sufficient detail to allow
characterization of the quality and
representativeness of the data or
information. Section VII of this
preamble provides more information on
submitting data.
VII. Submitting Data Corrections
The site-specific emissions profiles
used in the source category risk and
demographic analyses and instructions
are available for download on the RTR
Web site at https://www3.epa.gov/ttn/
atw/rrisk/rtrpg.html. The data files
include detailed information for each
HAP emissions release point for the
facilities in the source category.
If you believe that the data are not
representative or are inaccurate, please
identify the data in question, provide
your reason for concern, and provide
any ‘‘improved’’ data that you have, if
available. When you submit data, we
request that you provide documentation
of the basis for the revised values to
support your suggested changes. To
submit comments on the data
downloaded from the RTR Web site,
complete the following steps:
1. Within this downloaded file, enter
suggested revisions to the data fields
appropriate for that information.
2. Fill in the commenter information
fields for each suggested revision (i.e.,
commenter name, commenter
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organization, commenter email address,
commenter phone number, and revision
comments).
3. Gather documentation for any
suggested emissions revisions (e.g.,
performance test reports, material
balance calculations, etc.).
4. Send the entire downloaded file
with suggested revisions in Microsoft®
Access format and all accompanying
documentation to Docket ID No. EPA–
HQ–OAR–2016–0442 (through the
method described in the ADDRESSES
section of this preamble).
5. If you are providing comments on
a single facility or multiple facilities,
you need only submit one file for all
facilities. The file should contain all
suggested changes for all sources at that
facility. We request that all data revision
comments be submitted in the form of
updated Microsoft® Excel files that are
generated by the Microsoft® Access file.
These files are provided on the RTR
Web site at https://www3.epa.gov/ttn/
atw/rrisk/rtrpg.html.
VIII. Statutory and Executive Order
Reviews
Additional information about these
statutes and Executive Orders can be
found at https://www2.epa.gov/lawsregulations/laws-and-executive-orders.
A. Executive Order 12866: Regulatory
Planning and Review and Executive
Order 13563: Improving Regulation and
Regulatory Review
This action is not a significant
regulatory action and was, therefore, not
submitted to the Office of Management
and Budget (OMB) for review.
B. Executive Order 13771: Reducing
Regulations and Controlling Regulatory
Costs
This action is not expected to be an
Executive Order 13771 regulatory action
because this action is not significant
under Executive Order 12866.
C. Paperwork Reduction Act (PRA)
This action does not impose any new
information collection burden under the
PRA. OMB has previously approved the
information collection activities
contained in the existing regulations (40
CFR part 63, subpart LLL) and has
assigned OMB control number 2060–
0416. This action does not change the
information collection requirements.
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. In making this
determination, the impact of concern is
any significant adverse economic
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impact on small entities. An agency may
certify that a rule will not have a
significant economic impact on a
substantial number of small entities if
the rule relieves regulatory burden, has
no net burden, or otherwise has a
positive economic effect on the small
entities subject to the rule. We estimate
that three of the 26 existing Portland
cement entities are small entities and
comprise three plants. After considering
the economic impacts of this proposed
action on small entities, we have
concluded that this action will have no
net regulatory burden for all directly
regulated small entities.
E. Unfunded Mandates Reform Act
(UMRA)
This action does not contain an
unfunded mandate 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
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. It will neither impose
substantial direct compliance costs on
federally recognized tribal governments,
nor preempt tribal law. The EPA is
aware of one tribally owned Portland
cement facility currently subject to 40
CFR part 63, subpart LLL that will be
subject to this proposed action.
However, the provisions of this
proposed rule are not expected to
impose new or substantial direct
compliance costs on tribal governments
since the provisions in this proposed
action are clarifying and correcting
monitoring and testing requirements
and recordkeeping and reporting
requirements. This proposed action also
provides clarification for owners and
operators on bringing new or previously
furloughed kilns back on line. Thus,
Executive Order 13175 does not apply
to this action.
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H. Executive Order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
The EPA interprets Executive Order
13045 as applying only to those
regulatory actions that concern
environmental health or safety risks that
the EPA has reason to believe may
disproportionately affect children, per
the definition of ‘‘covered regulatory
action’’ in section 2–202 of the
Executive Order. This action is not
subject to Executive Order 13045
because it does not concern an
environmental health risk or safety risk.
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)
This rulemaking does not involve
technical standards.
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, lowincome 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.
List of Subjects in 40 CFR Part 63
Environmental protection,
Administrative practices and
procedures, Air pollution control,
Hazardous substances,
Intergovernmental relations, Reporting
and recordkeeping requirements.
asabaliauskas on DSKBBXCHB2PROD with PROPOSALS
Dated: September 1, 2017.
E. Scott Pruitt,
Administrator.
For the reasons stated in the
preamble, the Environmental Protection
Agency is proposing to amend title 40,
chapter I, part 63 of the Code of Federal
Regulations (CFR) as follows:
PART 63—NATIONAL EMISSION
STANDARDS FOR HAZARDOUS AIR
POLLUTANTS FOR SOURCE
CATEGORIES
1. The authority citation for part 63
continues to read as follows:
■
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Authority: 42 U.S.C. 7401 et seq.
Subpart LLL—National Emission
Standards for Hazardous Air Pollutants
for the Portland Cement Manufacturing
Industry
2. Section 63.1341 is amended by:
a. Removing the definition of
‘‘affirmative defense;’’ and
■ b. Revising the definitions of ‘‘dioxins
and furans (D/F),’’ ‘‘in-line coal mill,’’
and ‘‘TEQ.’’
The revisions read as follows:
■
■
§ 63.1341
Definitions
*
*
*
*
*
Dioxins and furans (D/F) means
tetra-, penta-, hexa-, hepta-, and octachlorinated dibenzo dioxins and furans.
*
*
*
*
*
In-line coal mill means a coal mill
using kiln exhaust gases in their
process. A coal mill with a heat source
other than the kiln or a coal mill using
exhaust gases from the clinker cooler is
not an in-line coal mill.
*
*
*
*
*
TEQ means the international method
of expressing toxicity equivalents for
dioxins and furans as defined in U.S.
EPA, Interim Procedures for Estimating
Risks Associated with Exposures to
Mixtures of Chlorinated Dibenzo-pdioxins and -dibenzofurans (CDDs and
CDFs) and 1989 Update, March 1989.
The 1989 Toxic Equivalency Factors
(TEFs) used to determine the dioxin and
furan TEQs are listed in Table 2 to
subpart LLL of Part 63.
*
*
*
*
*
§ 63.1343
[Amended]
3. Section 63.1343 is amended by
removing paragraph (d) and Table 2.
■ 4. Section 63.1348 is amended by:
■ a. Revising the first sentence in
paragraph (a) introductory text;
■ b. Revising paragraph (a)(3)(i);
■ c. Revising the second sentence in
paragraph (a)(3)(iv);
■ d. Revising paragraphs (a)(4)(ii),
(a)(7)(ii), (b)(3)(ii), and (b)(4);
■ e. Redesignating paragraph (b)(5)(i) as
paragraph (b)(5) introductory text;
■ f. Revising newly redesignated
paragraph (b)(5) introductory text; and
■ g. Adding new paragraph (b)(5)(i).
The revisions and addition read as
follows:
■
§ 63.1348
Compliance requirements.
(a) Initial Performance Test
Requirements. For an affected source
subject to this subpart, including any
affected source that was unable to
demonstrate compliance before the
compliance date due to being idled, or
that had demonstrated compliance but
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44281
was idled during the normal window for
the next compliance test, you must
demonstrate compliance with the
emissions standards and operating
limits by using the test methods and
procedures in §§ 63.1349 and 63.7.
*
*
*
*
*
(3) D/F compliance. (i) If you are
subject to limitations on D/F emissions
under § 63.1343(b), you must
demonstrate initial compliance with the
D/F emissions standards by using the
performance test methods and
procedures in § 63.1349(b)(3). The
owner or operator of a kiln with an inline raw mill must demonstrate initial
compliance by conducting separate
performance tests while the raw mill is
operating and the raw mill is not
operating. Determine the D/F TEQ
concentration for each run and calculate
the arithmetic average of the TEQ
concentrations measured for the three
runs to determine continuous
compliance.
*
*
*
*
*
(iv) * * * Compliance is
demonstrated if the system is
maintained within ±5 percent accuracy
during the performance test determined
in accordance with the procedures and
criteria submitted for review in your
monitoring plan required in
§ 63.1350(p).
(4) * * *
(ii) Total Organic HAP Emissions
Tests. If you elect to demonstrate
compliance with the total organic HAP
emissions limit under § 63.1343(b) in
lieu of the THC emissions limit, you
must demonstrate compliance with the
total organic HAP emissions standards
by using the performance test methods
and procedures in § 63.1349(b)(7).
*
*
*
*
*
(7) * * *
(ii) Perform required emission
monitoring and testing of the kiln
exhaust prior to the reintroduction of
the coal mill exhaust, and also testing
the kiln exhaust diverted to the coal
mill. All emissions must be added
together for all emission points, and
must not exceed the limit per each
pollutant as listed in § 63.1343(b).
(b) * * *
(3) * * *
(ii) Bag Leak Detection System
(BLDS). If you install a BLDS on a raw
mill or finish mill in lieu of conducting
the daily visible emissions testing, you
must demonstrate compliance using a
BLDS that is installed, operated, and
maintained in accordance with the
requirements of § 63.1350(f)(4)(ii).
(4) D/F Compliance. If you are subject
to a D/F emissions limitation under
§ 63.1343(b), you must demonstrate
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determine the applicable temperature
limit in accordance with § 63.1346(b).
*
*
*
*
*
(4) * * *
(i) If you are subject to limitations on
THC emissions, you must operate a
CEMS in accordance with the
requirements in § 63.1350(i). For the
purposes of conducting the accuracy
and quality assurance evaluations for
CEMS, the THC span value (as propane)
is 50 to 60 ppmvw and the reference
method (RM) is Method 25A of
appendix A to part 60 of this chapter.
*
*
*
*
*
(6) * * *
(i)(A) If the source is equipped with
a wet scrubber, tray tower or dry
scrubber, you must conduct
performance testing using Method 321
of appendix A to this part unless you
have installed a CEMS that meets the
requirements § 63.1350(l)(1). For kilns
with inline raw mills, testing must be
conducted for the raw mill on and raw
mill off conditions.
*
*
*
*
*
(7) * * *
(viii) * * *
(A) Determine the THC CEMS average
values in ppmvw, and the average of
your corresponding three total organic
HAP compliance test runs, using
Equation 12.
Where:
¯
x = The THC CEMS average values in
ppmvw.
Xi = The THC CEMS data points for all three
test runs i.
¯
y = The organic HAP average values in
ppmvw.
Yi = The organic HAP concentrations for all
three test runs i.
n = The number of data points.
the fraction of time the raw mill is on
and the fraction of time that the raw
mill is off, calculate this limit as a
weighted average of the SO2 levels
measured during raw mill on and raw
mill off compliance testing with
Equation 17.
Where:
R = Operating limit as SO2, ppmvw.
y = Average SO2 CEMS value during mill on
operations, ppmvw.
t = Percentage of operating time with mill on,
expressed as a decimal.
x = Average SO2 CEMS value during mill off
operations, ppmvw.
1-t = Percentage of operating time with mill
off, expressed as a decimal.
§ 63.1349 Performance testing
requirements.
*
*
*
*
*
(8) * * *
(vi) If your kiln has an inline kiln/raw
mill, you must conduct separate
performance tests while the raw mill is
operating (‘‘mill on’’) and while the raw
mill is not operating (‘‘mill off’’). Using
(vii) * * *
(B) Determine your SO2 CEMS
instrument average ppm, and the
average of your corresponding three HCl
compliance test runs, using equation 18.
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*
*
*
*
(b)(1) * * *
(vi) For each performance test,
conduct at least three separate test runs
under the conditions that exist when the
affected source is operating at the level
reasonably expected to occur. Conduct
each test run to collect a minimum
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sample volume of 2 dscm for
determining compliance with a new
source limit and 1 dscm for determining
compliance with an existing source
limit. Calculate the time weighted
average of the results from three
consecutive runs, including applicable
sources as required by paragraph
(b)(1)(viii) of this section, to determine
compliance. You need not determine
the particulate matter collected in the
impingers ‘‘back half’’ of the Method 5
or Method 5I particulate sampling train
to demonstrate compliance with the PM
standards of this subpart. This shall not
preclude the permitting authority from
requiring a determination of the ‘‘back
half’’ for other purposes. For kilns with
inline raw mills, testing must be
conducted while the raw mill is on and
while the raw mill is off. If the exhaust
streams of a kiln with an inline raw mill
and a clinker cooler are comingled, then
the comingled exhaust stream must be
tested with the raw mill on and the raw
mill off.
*
*
*
*
*
(3) * * *
(iv) The run average temperature must
be calculated for each run, and the
average of the run average temperatures
must be determined and included in the
performance test report and will
compliance using a continuous
monitoring system (CMS) that is
installed, operated and maintained to
record the temperature of specified gas
streams in accordance with the
requirements of § 63.1350(g).
(5) Activated Carbon Injection
Compliance. (i) If you use activated
carbon injection to comply with the D/
F emissions limitation under
§ 63.1343(b), you must demonstrate
compliance using a CMS that is
installed, operated, and maintained to
record the rate of activated carbon
injection in accordance with the
requirements § 63.1350(h)(1).
*
*
*
*
*
■ 5. Section 63.1349 is amended by:
■ a. Revising paragraphs (b)(1)(vi),
(3)(iv), (4)(i), (6)(i)(A), (7)(viii)(A),
(8)(vi), and (8)(vii)(B); and
■ b. Removing and reserving paragraph
(d).
The revisions read as follows:
Federal Register / Vol. 82, No. 182 / Thursday, September 21, 2017 / Proposed Rules
Where:
¯
x= The SO2 CEMS average values in ppmvw.
X1 = The SO2 CEMS data points for the three
runs constituting the performance test.
¯
y = The HCl average values in ppmvw.
Y1 = The HCl emission concentration
expressed as ppmv corrected to 7 percent
oxygen for the three runs constituting the
performance test.
n = The number of data points.
44283
linearity beyond the span value
established in paragraph (k)(1) of this
section using the following procedure.
Conduct a weekly ‘‘above span
linearity’’ calibration challenge of the
monitoring system using a reference gas
with a certified value greater than your
highest expected hourly concentration
or greater than 75 percent of the highest
measured hourly concentration. The
‘‘above span’’ reference gas must meet
the requirements of PS 12A, Section 7.1
and must be introduced to the
measurement system at the probe.
Record and report the results of this
procedure as you would for a daily
calibration. The ‘‘above span linearity’’
challenge is successful if the value
measured by the Hg CEMS falls within
10 percent of the certified value of the
reference gas. If the value measured by
the Hg CEMS during the above span
linearity challenge exceeds ±10 percent
of the certified value of the reference
gas, the monitoring system must be
evaluated and repaired and a new
‘‘above span linearity’’ challenge met
before returning the Hg CEMS to
service, or data above span from the Hg
CEMS must be subject to the quality
assurance procedures established in
paragraph (k)(2)(iii) of this section. In
this manner all hourly average values
exceeding the span value measured by
the Hg CEMS during the week following
the above span linearity challenge when
the CEMS response exceeds ±20 percent
of the certified value of the reference gas
must be normalized using Equation 22.
(iii) Quality assure any data above the
span value established in paragraph
(k)(1) of this section using the following
procedure. Any time two consecutive
one-hour average measured
concentrations of Hg exceeds the span
value you must, within 24 hours before
or after, introduce a higher, ‘‘above
span’’ Hg reference gas standard to the
Hg CEMS. The ‘‘above span’’ reference
gas must meet the requirements of PS
12A, Section 7.1, must target a
concentration level between 50 and 150
percent of the highest expected hourly
concentration measured during the
period of measurements above span,
and must be introduced at the probe.
While this target represents a desired
concentration range that is not always
achievable in practice, it is expected
that the intent to meet this range is
demonstrated by the value of the
reference gas. Expected values may
include ‘‘above span’’ calibrations done
before or after the above span
measurement period. Record and report
the results of this procedure as you
would for a daily calibration. The
‘‘above span’’ calibration is successful if
the value measured by the Hg CEMS is
within 20 percent of the certified value
of the reference gas. If the value
measured by the Hg CEMS exceeds 20
percent of the certified value of the
reference gas, then you must normalize
the one-hour average stack gas values
measured above the span during the 24hour period preceding or following the
‘‘above span’’ calibration for reporting
based on the Hg CEMS response to the
reference gas as shown in equation 22.
Only one ‘‘above span’’ calibration is
needed per 24 hour period.
*
*
*
*
*
(5) * * *
(ii) On a continuous basis, determine
the mass emissions of mercury in lb/hr
from the alkali bypass and coal mill
exhausts by using the mercury hourly
emissions rate and the exhaust gas flow
rate to calculate hourly mercury
emissions in lb/hr.
*
*
*
*
*
(l) * * *
(1) If you monitor compliance with
the HCl emissions limit by operating an
HCl CEMS, you must do so in
accordance with Performance
Specification 15 (PS 15) or PS 18 of
appendix B to part 60 of this chapter, or,
*
*
*
*
*
(d) [Reserved]
*
*
*
*
*
■ 6. Section 63.1350 is amended by:
■ a. Revising paragraphs (g)
introductory text, (g)(4), (h)(2)(ii), (j),
(k)(2) introductory text, (k)(2)(ii), and
(k)(2)(iii); and
■ b. Revising paragraphs (k)(5)(ii), (l)(1)
introductory text, and (l)(3).
The revisions read as follows:
§ 63.1350
Monitoring requirements.
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*
*
*
*
(g) D/F monitoring requirements. If
you are subject to an emissions
limitation on D/F emissions, you must
comply with the monitoring
requirements of paragraphs (g)(1)
through (g)(5) and paragraphs (m)(1)
through (m)(4) of this section to
demonstrate continuous compliance
with the D/F emissions standard. You
must also develop an emissions
monitoring plan in accordance with
paragraphs (p)(1) through (p)(4) of this
section.
*
*
*
*
*
(4) Every hour, report the calculated
rolling three-hour average temperature
using the average of 180 successive one-
minute average temperatures. See
S63.1349(b)(3).
*
*
*
*
*
(h) * * *
(2) * * *
(ii) Each hour, calculate the threehour rolling average of the selected
parameter value for the previous 3 hours
of process operation using all of the oneminute data available (i.e., the CMS is
not out-of-control).
*
*
*
*
*
(j) Total organic HAP monitoring
requirements. If you are complying with
the total organic HAP emissions limits,
you must continuously monitor THC
according to paragraph (i)(1) and (2) of
this section or in accordance with
Performance Specification 8 or
Performance Specification 8A of
appendix B to part 60 of this chapter
and comply with all of the requirements
for continuous monitoring systems
found in the general provisions, subpart
A of this part. You must operate and
maintain each CEMS according to the
quality assurance requirements in
Procedure 1 of appendix F in part 60 of
this chapter. You must also develop an
emissions monitoring plan in
accordance with paragraphs (p)(1)
through (4) of this section.
(k) * * *
(2) In order to quality assure data
measured above the span value, you
must use one of the three options in
paragraphs (k)(2)(i) through (iii) of this
section.
*
*
*
*
*
(ii) Quality assure any data above the
span value by proving instrument
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upon promulgation, in accordance with
any other performance specification for
HCl CEMS in appendix B to part 60 of
this chapter. You must operate,
maintain, and quality assure a HCl
CEMS installed and certified under PS
15 according to the quality assurance
requirements in Procedure 1 of
appendix F to part 60 of this chapter
except that the Relative Accuracy Test
Audit requirements of Procedure 1 must
be replaced with the validation
requirements and criteria of sections
11.1.1 and 12.0 of PS 15. If you choose
to install and operate an HCl CEMS in
accordance with PS 18 of appendix B to
part 60 of this chapter, you must
operate, maintain, and quality assure
the HCl CEMS using the associated
Procedure 6 of appendix F to part 60 of
this chapter. For any performance
specification that you use, you must use
Method 321 of appendix A to part 63 of
this chapter as the reference test method
for conducting relative accuracy testing.
The span value and calibration
requirements in paragraphs (l)(1)(i) and
(ii) of this section apply to HCl CEMS
other than those installed and certified
under PS 15 or PS 18.
*
*
*
*
*
(3) If the source is equipped with a
wet or dry scrubber or tray tower, and
you choose to monitor SO2 emissions,
monitor SO2 emissions continuously
according to the requirements of
§ 60.63(e) and (f) of part 60 subpart F of
this chapter. If SO2 levels increase above
the 30-day rolling average SO2 operating
limit established during your
performance test by 10 percent or more,
you must:
(i) As soon as possible but no later
than 30 days after you exceed the
established SO2 value conduct an
inspection and take corrective action to
return the SO2 emissions to within the
operating limit; and
(ii) Within 90 days of the exceedance
or at the time of the next compliance
test, whichever comes first, conduct an
HCl emissions compliance test to
determine compliance with the HCl
emissions limit and to verify or reestablish the SO2 CEMS operating limit.
*
*
*
*
*
■ 7. Section 63.1354 is amended by
revising paragraph (b)(9) introductory
text, (9)(vi), (9)(viii), and (10); and
paragraph (c) to read as follows:
§ 63.1354
Reporting requirements.
*
*
*
*
*
(b) * * *
(9) The owner or operator shall
submit a summary report semiannually
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within 60 days of the reporting period
to the EPA via the Compliance and
Emissions Data Reporting Interface
(CEDRI). (CEDRI can be accessed
through the EPA’s Central Data
Exchange (CDX) (www.epa.gov/cdx).)
You must use the appropriate electronic
report in CEDRI for this subpart. Instead
of using the electronic report in CEDRI
for this subpart, you may submit an
alternate electronic file consistent with
the extensible markup language (XML)
schema listed on the CEDRI Web site
(https://www.epa.gov/electronicreporting-air-emissions/complianceand-emissions-data-reporting-interfacecedri), once the XML schema is
available. If the reporting form specific
to this subpart is not available in CEDRI
at the time that the report is due, you
must submit the report the
Administrator at the appropriate
address listed in § 63.13. You must
begin submitting reports via CEDRI no
later than 90 days after the form
becomes available in CEDRI. The excess
emissions and summary reports must be
submitted no later than 60 days after the
end of the reporting period, regardless
of the method in which the reports are
submitted. The report must contain the
information specified in
§ 63.10(e)(3)(vi). In addition, the
summary report shall include:
*
*
*
*
*
(vi) For each PM CPMS, HCl, Hg, and
THC CEMS, or Hg sorbent trap
monitoring system, within 60 days after
the reporting periods, you must report
all of the calculated 30-operating day
rolling average values derived from the
CPMS, CEMS, CMS, or Hg sorbent trap
monitoring systems.
*
*
*
*
*
(viii) You must submit the
information specified in paragraphs
(b)(9)(viii)(A) and (B) of this section no
later than 60 days following the initial
performance test. All reports must be
signed by a responsible official.
(A) The initial performance test data
as recorded under § 63.1349(a).
(B) The values for the site-specific
operating limits or parameters
established pursuant to § 63.1349(b)(1),
(3), (6), (7), and (8), as applicable, and
a description, including sample
calculations, of how the operating
parameters were established during the
initial performance test.
(C) As of December 31, 2011, and
within 60 days after the date of
completing each performance
evaluation or test, as defined in § 63.2,
conducted to demonstrate compliance
with any standard covered by this
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subpart, you must submit the relative
accuracy test audit data and
performance test data, except opacity
data, to the EPA by successfully
submitting the data electronically to the
EPA’s Central Data Exchange (CDX) by
using the Electronic Reporting Tool
(ERT) (see https://www.epa.gov/
electronic-reporting-air-emissions/
electronic-reporting-tool-ert). For any
performance evaluations with no
corresponding RATA pollutants listed
on the ERT Web site, you must submit
the results of the performance
evaluation to the Administrator at the
appropriate address listed in § 63.13.
*
*
*
*
*
(10) If the total continuous monitoring
system downtime for any CEM or any
CMS for the reporting period is 10
percent or greater of the total operating
time for the reporting period, the owner
or operator shall submit an excess
emissions and continuous monitoring
system performance report along with
the summary report.
(c) Reporting a failure to meet a
standard due to a malfunction. For each
failure to meet a standard or emissions
limit caused by a malfunction at an
affected source, you must report the
failure in the semi-annual compliance
report required by § 63.1354(b)(9). The
report must contain the date, time and
duration, and the cause of each event
(including unknown cause, if
applicable), and a sum of the number of
events in the reporting period. The
report must list for each event the
affected source or equipment, an
estimate of the amount of each regulated
pollutant emitted over the emission
limit for which the source failed to meet
a standard, and a description of the
method used to estimate the emissions.
The report must also include a
description of actions taken by an owner
or operator during a malfunction of an
affected source to minimize emissions
in accordance with § 63.1348(d),
including actions taken to correct a
malfunction.
■ 8. Section 63.1355 is amended by
revising paragraph (e) to read as follows:
§ 63.1355
Recordkeeping requirements.
*
*
*
*
*
(e) You must keep records of the daily
clinker production rates according to
the clinker production monitoring
requirements in § 63.1350(d).
*
*
*
*
*
■ 9. Table 1 to subpart LLL of part 63
is amended by adding the entry
‘‘63.10(e)(3)(v)’’ to read as follows:
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TABLE 1 TO SUBPART LLL OF PART 63—APPLICABILITY OF GENERAL PROVISIONS
Citation
Requirement
Applies to subpart LLL
*
63.10(e)(3)(v) .................
*
*
*
Due Dates for Excess Emissions and CMS ..........
Performance Reports
*
No ..................................
*
*
*
*
Explanation
*
*
§ 63.1354(b)(9) specifies due date.
*
*
*
10. Add table 2 to subpart LLL of part
63 to read as follows:
■
TABLE 2 TO SUBPART LLL OF PART 63—1989 TOXIC EQUIVALENCY FACTORS (TEFS)
Dioxins/furans
TEFs 1989
2,3,7,8-TCDD .................................................................................................................................................................................
1,2,3,7,8-PeCDD ............................................................................................................................................................................
1,2,3,4,7,8-HxCDD .........................................................................................................................................................................
1,2,3,6,7,8-HxCDD .........................................................................................................................................................................
1,2,3,7,8,9-HxCDD .........................................................................................................................................................................
1,2,3,4,6,7,8-HpCDD .....................................................................................................................................................................
OCDD ............................................................................................................................................................................................
2,3,7,8-TCDF .................................................................................................................................................................................
1,2,3,7,8-PeCDF ............................................................................................................................................................................
2,3,4,7,8-PeCDF ............................................................................................................................................................................
1,2,3,4,7,8-HxCDF .........................................................................................................................................................................
1,2,3,6,7,8-HxCDF .........................................................................................................................................................................
1,2,3,7,8,9-HxCDF .........................................................................................................................................................................
2,3,4,6,7,8-HxCDF .........................................................................................................................................................................
1,2,3,4,6,7,8-HpCDF ......................................................................................................................................................................
1,2,3,4,7,8,9-HpCDF ......................................................................................................................................................................
OCDF .............................................................................................................................................................................................
[FR Doc. 2017–19448 Filed 9–20–17; 8:45 am]
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Agencies
[Federal Register Volume 82, Number 182 (Thursday, September 21, 2017)]
[Proposed Rules]
[Pages 44254-44285]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-19448]
[[Page 44253]]
Vol. 82
Thursday,
No. 182
September 21, 2017
Part II
Environmental Protection Agency
-----------------------------------------------------------------------
40 CFR Part 63
National Emission Standards for Hazardous Air Pollutants From the
Portland Cement Manufacturing Industry Residual Risk and Technology
Review; Proposed Rule
Federal Register / Vol. 82 , No. 182 / Thursday, September 21, 2017 /
Proposed Rules
[[Page 44254]]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 63
[EPA-HQ-OAR-2016-0442; FRL-9967-61-OAR]
RIN 2060-AS92
National Emission Standards for Hazardous Air Pollutants From the
Portland Cement Manufacturing Industry Residual Risk and Technology
Review
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) is proposing
amendments to the National Emission Standards for Hazardous Air
Pollutants (NESHAP) From the Portland Cement Manufacturing Industry to
address the results of the residual risk and technology review (RTR)
the EPA is required to conduct in accordance with section 112 of the
Clean Air Act (CAA). We found risks due to emissions of air toxics to
be acceptable from this source category with an ample margin of safety,
and we identified no new cost-effective controls under the technology
review to achieve further emissions reductions. Therefore, we are
proposing no revisions to the numerical emission limits based on these
analyses. However, the EPA is proposing amendments to correct and
clarify rule requirements and provisions. While the proposed amendments
would not result in reductions in emissions of hazardous air pollutants
(HAP), this action, if finalized, would result in improved monitoring,
compliance, and implementation of the rule.
DATES:
Comments. Comments must be received on or before November 6, 2017.
Public Hearing. If a public hearing is requested by September 26,
2017, the EPA will hold a public hearing on October 6, 2017. The last
day to pre-register in advance to speak at the public hearing will be
October 4, 2017.
ADDRESSES: Comments. Submit your comments, identified by Docket ID No.
EPA-HQ-OAR-2016-0442, at https://www.regulations.gov. Follow the online
instructions for submitting comments. Once submitted, comments cannot
be edited or removed from Regulations.gov. The EPA may publish any
comment received to its public docket. Do not submit electronically any
information you consider to be Confidential Business Information (CBI)
or other information whose disclosure is restricted by statute.
Multimedia submissions (audio, video, etc.) must be accompanied by a
written comment. The written comment is considered the official comment
and should include discussion of all points you wish to make. The EPA
will generally not consider comments or comment contents located
outside of the primary submission (i.e., on the Web, cloud, or other
file sharing system). For additional submission methods, the full EPA
public comment policy, information about CBI or multimedia submissions,
and general guidance on making effective comments, please visit https://www2.epa.gov/dockets/commenting-epa-dockets.
Public Hearing. If a hearing is requested, it will be held at the
EPA WJC East Building, 1201 Constitution Avenue NW., Washington, DC
20004. If a public hearing is requested, then we will provide details
about the public hearing on our Web site at https://www.epa.gov/stationary-sources-air-pollution/portland-cement-manufacturing-industry-national-emission-standards. The EPA does not intend to
publish any future notices in the Federal Register announcing any
updates on the request for public hearing. Please contact Aimee St.
Clair at (919) 541-1063 or by email at stclair.aimee@epa.gov to request
a public hearing, to register to speak at the public hearing, or to
inquire as to whether a public hearing will be held.
FOR FURTHER INFORMATION CONTACT: For questions about this proposed
action, contact Mr. Brian Storey, Sector Policies and Programs Division
(D243-04), Office of Air Quality Planning and Standards, U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina
27711; telephone number: (919) 541-1103; fax number: (919) 541-5450;
and email address: storey.brian@epa.gov. For specific information
regarding the risk modeling methodology, contact Mr. James Hirtz,
Health and Environmental Impacts Division (C539-02), Office of Air
Quality Planning and Standards, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711; telephone number: (919)
541-0881; fax number: (919) 541-0840; and email address:
hirtz.james@epa.gov. For information about the applicability of the
NESHAP to a particular entity, contact Ms. Sara Ayres, Office of
Enforcement and Compliance Assurance, U.S. Environmental Protection
Agency, U.S. EPA Region 5 (E-19J), 77 West Jackson Boulevard, Chicago,
IL 60604; telephone number: (312) 353-6266; email address:
ayres.sara@epa.gov.
SUPPLEMENTARY INFORMATION:
Docket. The EPA has established a docket for this rulemaking under
Docket ID No. EPA-HQ-OAR-2016-0442. All documents in the docket are
listed in the Regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, is not placed on the Internet and will be
publicly available only in hard copy. Publicly available docket
materials are available either electronically in Regulations.gov or in
hard copy at the EPA Docket Center, Room 3334, EPA WJC West Building,
1301 Constitution Avenue NW., Washington, DC. The Public Reading Room
is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. The telephone number for the Public Reading Room is
(202) 566-1744, and the telephone number for the EPA Docket Center is
(202) 566-1742.
Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2016-0442. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at https://www.regulations.gov, including any personal
information provided, unless the comment includes information claimed
to be CBI or other information whose disclosure is restricted by
statute. Do not submit information that you consider to be CBI or
otherwise protected through https://www.regulations.gov or email. The
https://www.regulations.gov Web site is an ``anonymous access'' system,
which means the EPA will not know your identity or contact information
unless you provide it in the body of your comment. If you send an email
comment directly to the EPA without going through https://www.regulations.gov, your email address will be automatically captured
and included as part of the comment that is placed in the public docket
and made available on the Internet. If you submit an electronic
comment, the EPA recommends that you include your name and other
contact information in the body of your comment and with any disk or
CD-ROM you submit. If the EPA cannot read your comment due to technical
difficulties and cannot contact you for clarification, the EPA may not
be able to consider your comment. Electronic files should not include
special characters or any form of encryption and be free of any defects
or
[[Page 44255]]
viruses. For additional information about the EPA's public docket,
visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
Preamble Acronyms and Abbreviations. We use multiple acronyms and
terms in this preamble. While this list may not be exhaustive, to ease
the reading of this preamble and for reference purposes, the EPA
defines the following terms and acronyms here:
ACI activated carbon injection
AEGL acute exposure guideline levels
AERMOD air dispersion model used by the HEM-3 model
CAA Clean Air Act
CalEPA California EPA
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CISWI commercial and industrial solid waste incinerators
CO carbon monoxide
D/F dioxins and furans
EPA Environmental Protection Agency
ERP Emergency Response Planning
ERPG Emergency Response Planning Guidelines
ERT Electronic Reporting Tool
ESP electrostatic precipitators
FR Federal Register
GHGRP Greenhouse Gas Reporting Program
HAP hazardous air pollutants
HCl hydrochloric acid
HEM-3 Human Exposure Model
HF hydrogen fluoride
HI hazard index
HQ hazard quotient
IRIS Integrated Risk Information System
km kilometer
lb/hr pounds per hour
lb/ton pounds per ton
LOAEL lowest-observed-adverse-effect level
MACT maximum achievable control technology
mg/kg-day milligrams per kilogram per day
mg/m\3\ milligrams per cubic meter
mg/Nm\3\ milligrams per normal cubic meter
MIR maximum individual risk
NAAQS National Ambient Air Quality Standards
NAC National Advisory Committee
NAICS North American Industry Classification System
NAS National Academy of Sciences
NATA National Air Toxics Assessment
NEI National Emissions Inventory
NESHAP national emission standards for hazardous air pollutants
NOX nitrogen oxides
NOAA National Oceanic and Atmospheric Administration
NOAEL no-observed-adverse-effect level
NRC National Research Council
NRDC Natural Resources Defense Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PCA Portland Cement Association
PEL probable effect level
PM particulate matter
POM polycyclic organic matter
ppm parts per million
ppmvd parts per million by volume, dry basis
PRA Paperwork Reduction Act
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RfD reference dose
RTO regenerative thermal oxidizers
RTR residual risk and technology review
SAB Science Advisory Board
SCR selective catalytic reduction
SO2 sulfur dioxide
TEF toxicity equivalence factors
TEQ toxic equivalents
THC total hydrocarbons
TOSHI target organ-specific hazard index
tpy tons per year
TRIM.FaTE Total Risk Integrated Methodology.Fate, Transport, and
Ecological Exposure model
UF uncertainty factor
[micro]g/m\3\ microgram per cubic meter
UISIS Universal Industrial Sectors Integrated Solutions
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
U.S.C. United States Code
WebFIRE Web Factor Information Retrieval System
Organization of this Document. The information in this preamble is
organized as follows:
I. General Information
A. Does this action apply to me?
B. Where can I get a copy of this document and other related
information?
C. What should I consider as I prepare my comments for the EPA?
II. Background
A. What is the statutory authority for this action?
B. What is this source category and how does the current NESHAP
regulate its HAP emissions?
C. What data collection activities were conducted to support
this action?
D. What other relevant background information and data are
available?
III. Analytical Procedures
A. How did we estimate post-MACT risks posed by the source
category?
B. How did we consider the risk results in making decisions for
this proposal?
C. How did we perform the technology review?
IV. Analytical Results and Proposed Decisions
A. What are the results of the risk assessment and analyses?
B. What are our proposed decisions regarding risk acceptability,
ample margin of safety, and adverse environmental effects?
C. What are the results and proposed decisions based on our
technology review?
D. What other actions are we proposing?
E. What compliance dates are we proposing?
V. Summary of Cost, Environmental, and Economic Impacts
A. What are the impacts to affected sources?
B. What are the air quality impacts?
C. What are the cost impacts?
D. What are the economic impacts?
E. What are the benefits?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. Statutory and Executive Order Reviews
A. Executive Order 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)
K. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
I. General Information
A. Does this action apply to me?
Table 1 of this preamble lists the NESHAP and associated regulated
industrial source category that is the subject of this proposal. Table
1 is not intended to be exhaustive, but rather provides a guide for
readers regarding the entities that this proposed action is likely to
affect. The proposed standards, once promulgated, will be directly
applicable to the affected sources. Federal, state, local, and tribal
government entities would not be affected by this proposed action. As
defined in the Initial List of Categories of Sources Under Section
112(c)(1) of the Clean Air Act Amendments of 1990 (see 57 FR 31576,
July 16, 1992), the Portland Cement Manufacturing Industry source
category is any facility engaged in manufacturing Portland cement by
either the wet or dry process. The category includes, but is not
limited to, the following process units: Kiln, clinker cooler, raw mill
system, finish mill system, raw mill dryer, raw material storage,
clinker storage, finished product storage, conveyor transfer points,
bagging, and bulk loading and unloading systems.
[[Page 44256]]
Table 1--NESHAP and Industrial Source Categories Affected by This
Proposed Action
------------------------------------------------------------------------
Source category NESHAP NAICS code \1\
------------------------------------------------------------------------
Portland cement manufacturing 40 CFR part 63 327310
facilities. subpart LLL.
------------------------------------------------------------------------
\1\ North American Industry Classification System.
The source category does not include those kilns that burn hazardous
waste and are subject to and regulated under 40 CFR part 63, subpart
EEE, or kilns that burn solid waste and are subject to the Commercial
and Industrial Solid Waste Incinerator (CISWI) rule under 40 CFR part
60, subparts CCCC and DDDD.
B. Where can I get a copy of this document and other related
information?
In addition to being available in the docket, an electronic copy of
this action is available on the Internet. Following signature by the
EPA Administrator, the EPA will post a copy of this proposed action at
https://www3.epa.gov/airquality/cement/actions.html. Following
publication in the Federal Register, the EPA will post the Federal
Register version of the proposal and key technical documents at this
same Web site. Information on the overall RTR program is available at
https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
C. What should I consider as I prepare my comments for the EPA?
Submitting CBI. Do not submit information containing CBI to the EPA
through https://www.regulations.gov or email. Clearly mark the part or
all of the information that you claim to be CBI. For CBI information on
a disk or CD-ROM that you mail to the EPA, mark the outside of the disk
or CD-ROM as CBI and then identify electronically within the disk or
CD-ROM the specific information that is claimed as CBI. In addition to
one complete version of the comments that includes information claimed
as CBI, you must submit a copy of the comments that does not contain
the information claimed as CBI for inclusion in the public docket. If
you submit a CD-ROM or disk that does not contain CBI, mark the outside
of the disk or CD-ROM clearly that it does not contain CBI. Information
not marked as CBI will be included in the public docket and the EPA's
electronic public docket without prior notice. Information marked as
CBI will not be disclosed except in accordance with procedures set
forth in 40 Code of Federal Regulations (CFR) part 2. Send or deliver
information identified as CBI only to the following address: OAQPS
Document Control Officer (C404-02), OAQPS, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina 27711,
Attention Docket ID No. EPA-HQ-OAR-2016-0442.
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, after the EPA has identified categories of sources emitting one
or more of the HAP listed in CAA section 112(b), CAA section 112(d)
requires us to promulgate technology-based NESHAP for those sources.
``Major sources'' are those that emit or have the potential to emit 10
tons per year (tpy) or more of a single HAP or 25 tpy or more of any
combination of HAP. For major sources, the technology-based NESHAP must
reflect the maximum degree of emission reductions of HAP achievable
(after considering cost, energy requirements, and non-air quality
health and environmental impacts) and are commonly referred to as
maximum achievable control technology (MACT) standards.
MACT standards must reflect the maximum degree of emissions
reduction achievable through the application of measures, processes,
methods, systems, or techniques, including, but not limited to,
measures that: (1) Reduce the volume of or eliminate pollutants through
process changes, substitution of materials, or other modifications; (2)
enclose systems or processes to eliminate emissions; (3) capture or
treat pollutants when released from a process, stack, storage, or
fugitive emissions point; (4) are design, equipment, work practice, or
operational standards (including requirements for operator training or
certification); or (5) are a combination of the above. CAA section
112(d)(2)(A)-(E). The MACT standards may take the form of design,
equipment, work practice, or operational standards where the EPA first
determines either that: (1) A pollutant cannot be emitted through a
conveyance designed and constructed to emit or capture the pollutant,
or that any requirement for, or use of, such a conveyance would be
inconsistent with law; or (2) the application of measurement
methodology to a particular class of sources is not practicable due to
technological and economic limitations. CAA section 112(h)(1)-(2).
The MACT ``floor'' is the minimum control level allowed for MACT
standards promulgated under CAA section 112(d)(3) and may not be based
on cost considerations. For new sources, the MACT floor cannot be less
stringent than the emissions control that is achieved in practice by
the best-controlled similar source. The MACT floor for existing sources
can be less stringent than floors for new sources, but not less
stringent than the average emissions limitation achieved by the best-
performing 12 percent of existing sources in the category or
subcategory (or the best-performing five sources for categories or
subcategories with fewer than 30 sources). In developing MACT
standards, the EPA must also consider control options that are more
stringent than the floor. We may establish standards more stringent
than the floor based on considerations of the cost of achieving the
emission reductions, any non-air quality health and environmental
impacts, and energy requirements.
The EPA is then required to review these technology-based standards
and revise them ``as necessary (taking into account developments in
practices, processes, and control technologies)'' no less frequently
than every 8 years. CAA section 112(d)(6). In conducting this review,
the EPA is not required to recalculate the MACT floor. Natural
Resources Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir.
2008). Association of Battery Recyclers, Inc. v. EPA, 716 F.3d 667
(D.C. Cir. 2013).
The second stage in standard-setting focuses on reducing any
remaining (i.e., ``residual'') risk according to CAA section 112(f).
Section 112(f)(1) of the CAA required that the EPA prepare a report to
Congress discussing (among other things) methods of calculating the
risks posed (or potentially posed) by sources after implementation of
the MACT standards, the public health significance of those risks, and
the EPA's recommendations as to legislation regarding such remaining
risk. The EPA prepared and submitted the Residual Risk Report to
Congress, EPA-453/R-99-001 (Risk Report) in March 1999.
[[Page 44257]]
Section 112(f)(2) of the CAA then provides that if Congress does not
act on any recommendation in the Risk Report, the EPA must analyze and
address residual risk for each category or subcategory of sources 8
years after promulgation of such standards pursuant to CAA section
112(d).
Section 112(f)(2) of the CAA requires the EPA to determine for
source categories subject to MACT standards whether promulgation of
additional standards is needed to provide an ample margin of safety to
protect public health. Section 112(f)(2)(B) of the CAA expressly
preserves the EPA's use of the two-step process for developing
standards to address any residual risk and the Agency's interpretation
of ``ample margin of safety'' developed in the National Emissions
Standards for Hazardous Air Pollutants: Benzene Emissions from Maleic
Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene Storage Vessels,
Benzene Equipment Leaks, and Coke By-Product Recovery Plants (Benzene
NESHAP) (54 FR 38044, September 14, 1989). The EPA notified Congress in
the Risk Report that the Agency intended to use the Benzene NESHAP
approach in making CAA section 112(f) residual risk determinations
(EPA-453/R-99-001, p. ES-11). The EPA subsequently adopted this
approach in its residual risk determinations and in a challenge to the
risk review for the Synthetic Organic Chemical Manufacturing source
category, the United States Court of Appeals for the District of
Columbia Circuit (the Court) upheld as reasonable the EPA's
interpretation that CAA section 112(f)(2) incorporates the approach
established in the Benzene NESHAP. See NRDC v. EPA, 529 F.3d 1077, 1083
(D.C. Cir. 2008) (``[S]ubsection 112(f)(2)(B) expressly incorporates
the EPA's interpretation of the Clean Air Act from the Benzene
standard, complete with a citation to the Federal Register.''); see
also, A Legislative History of the Clean Air Act Amendments of 1990,
vol. 1, p. 877 (Senate debate on Conference Report).
The first step in the process of evaluating residual risk is the
determination of acceptable risk. If risks are unacceptable, the EPA
cannot consider cost in identifying the emissions standards necessary
to bring risks to an acceptable level. The second step is the
determination of whether standards must be further revised in order to
provide an ample margin of safety to protect public health. The ample
margin of safety is the level at which the standards must be set,
unless an even more stringent standard is necessary to prevent, taking
into consideration costs, energy, safety, and other relevant factors,
an adverse environmental effect.
1. Step 1--Determination of Acceptability
The Agency in the Benzene NESHAP concluded that ``the acceptability
of risk under section 112 is best judged on the basis of a broad set of
health risk measures and information'' and that the ``judgment on
acceptability cannot be reduced to any single factor.'' Benzene NESHAP
at 38046. The determination of what represents an ``acceptable'' risk
is based on a judgment of ``what risks are acceptable in the world in
which we live'' (Risk Report at 178, quoting NRDC v. EPA, 824 F. 2d
1146, 1165 (D.C. Cir. 1987) (en banc) (``Vinyl Chloride''), recognizing
that our world is not risk-free.
In the Benzene NESHAP, we stated that ``EPA will generally presume
that if the risk to [the maximum exposed] individual is no higher than
approximately one in 10 thousand, that risk level is considered
acceptable.'' 54 FR at 38045, September 14, 1989. We discussed the
maximum individual lifetime cancer risk (or maximum individual risk
(MIR)) as being ``the estimated risk that a person living near a plant
would have if he or she were exposed to the maximum pollutant
concentrations for 70 years.'' Id. We explained that this measure of
risk ``is an estimate of the upper bound of risk based on conservative
assumptions, such as continuous exposure for 24 hours per day for 70
years.'' Id. We acknowledged that maximum individual lifetime cancer
risk ``does not necessarily reflect the true risk, but displays a
conservative risk level which is an upper-bound that is unlikely to be
exceeded.'' Id.
Understanding that there are both benefits and limitations to using
the MIR as a metric for determining acceptability, we acknowledged in
the Benzene NESHAP that ``consideration of maximum individual risk * *
* must take into account the strengths and weaknesses of this measure
of risk.'' Id. Consequently, the presumptive risk level of 100-in-1
million (1-in-10 thousand) provides a benchmark for judging the
acceptability of maximum individual lifetime cancer risk, but does not
constitute a rigid line for making that determination. Further, in the
Benzene NESHAP, we noted that:
[p]articular attention will also be accorded to the weight of
evidence presented in the risk assessment of potential
carcinogenicity or other health effects of a pollutant. While the
same numerical risk may be estimated for an exposure to a pollutant
judged to be a known human carcinogen, and to a pollutant considered
a possible human carcinogen based on limited animal test data, the
same weight cannot be accorded to both estimates. In considering the
potential public health effects of the two pollutants, the Agency's
judgment on acceptability, including the MIR, will be influenced by
the greater weight of evidence for the known human carcinogen.
Id. at 38046. The Agency also explained in the Benzene NESHAP that:
[i]n establishing a presumption for MIR, rather than a rigid line
for acceptability, the Agency intends to weigh it with a series of
other health measures and factors. These include the overall
incidence of cancer or other serious health effects within the
exposed population, the numbers of persons exposed within each
individual lifetime risk range and associated incidence within,
typically, a 50 km exposure radius around facilities, the science
policy assumptions and estimation uncertainties associated with the
risk measures, weight of the scientific evidence for human health
effects, other quantified or unquantified health effects, effects
due to co-location of facilities, and co-emission of pollutants.
Id. at 38045. In some cases, these health measures and factors taken
together may provide a more realistic description of the magnitude of
risk in the exposed population than that provided by maximum individual
lifetime cancer risk alone.
As noted earlier, in NRDC v. EPA, the Court held that CAA section
112(f)(2) ``incorporates the EPA's interpretation of the Clean Air Act
from the Benzene Standard.'' The Court further held that Congress'
incorporation of the Benzene standard applies equally to carcinogens
and non-carcinogens. 529 F.3d at 1081-82. Accordingly, we also consider
non-cancer risk metrics in our determination of risk acceptability and
ample margin of safety.
2. Step 2--Determination of Ample Margin of Safety
Section 112(f)(2) of the CAA requires the EPA to determine, for
source categories subject to MACT standards, whether those standards
provide an ample margin of safety to protect public health. As
explained in the Benzene NESHAP, ``the second step of the inquiry,
determining an `ample margin of safety,' again includes consideration
of all of the health factors, and whether to reduce the risks even
further * * *. Beyond that information, additional factors relating to
the appropriate level of control will also be considered, including
costs and economic impacts of controls, technological feasibility,
uncertainties, and any other relevant factors. Considering all of these
factors, the agency will establish the standard at
[[Page 44258]]
a level that provides an ample margin of safety to protect the public
health, as required by section 112.'' 54 FR 38046, September 14, 1989.
According to CAA section 112(f)(2)(A), if the MACT standards for
HAP ``classified as a known, probable, or possible human carcinogen do
not reduce lifetime excess cancer risks to the individual most exposed
to emissions from a source in the category or subcategory to less than
one in one million,'' the EPA must promulgate residual risk standards
for the source category (or subcategory), as necessary to provide an
ample margin of safety to protect public health. In doing so, the EPA
may adopt standards equal to existing MACT standards if the EPA
determines that the existing standards (i.e., the MACT standards) are
sufficiently protective. NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir.
2008) (``If EPA determines that the existing technology-based standards
provide an 'ample margin of safety,' then the Agency is free to readopt
those standards during the residual risk rulemaking.'') The EPA must
also adopt more stringent standards, if necessary, to prevent an
adverse environmental effect,\1\ but must consider cost, energy,
safety, and other relevant factors in doing so.
---------------------------------------------------------------------------
\1\ ``Adverse environmental effect'' is defined as any
significant and widespread adverse effect, which may be reasonably
anticipated to wildlife, aquatic life, or natural resources,
including adverse impacts on populations of endangered or threatened
species or significant degradation of environmental qualities over
broad areas. CAA section 112(a)(7).
---------------------------------------------------------------------------
The CAA does not specifically define the terms ``individual most
exposed,'' ``acceptable level,'' and ``ample margin of safety.'' In the
Benzene NESHAP, 54 FR at 38044-38045, September 14, 1989, we stated as
an overall objective:
In protecting public health with an ample margin of safety under
section 112, EPA strives to provide maximum feasible protection
against risks to health from hazardous air pollutants by (1)
protecting the greatest number of persons possible to an individual
lifetime risk level no higher than approximately 1-in-1 million and
(2) limiting to no higher than approximately 1-in-10 thousand [i.e.,
100-in-1 million] the estimated risk that a person living near a
plant would have if he or she were exposed to the maximum pollutant
concentrations for 70 years.
The Agency further stated that ``[t]he EPA also considers incidence
(the number of persons estimated to suffer cancer or other serious
health effects as a result of exposure to a pollutant) to be an
important measure of the health risk to the exposed population.
Incidence measures the extent of health risks to the exposed population
as a whole, by providing an estimate of the occurrence of cancer or
other serious health effects in the exposed population.'' Id. at 38045.
In the ample margin of safety decision process, the Agency again
considers all of the health risks and other health information
considered in the first step, including the incremental risk reduction
associated with standards more stringent than the MACT standard or a
more stringent standard that the EPA has determined is necessary to
ensure risk is acceptable. In the ample margin of safety analysis, the
Agency considers additional factors, including costs and economic
impacts of controls, technological feasibility, uncertainties, and any
other relevant factors. Considering all of these factors, the Agency
will establish the standard at a level that provides an ample margin of
safety to protect the public health, as required by CAA section 112(f).
54 FR 38046, September 14, 1989.
B. What is this source category and how does the current NESHAP
regulate its HAP emissions?
The EPA initially promulgated the Portland Cement Manufacturing
Industry NESHAP on June 14, 1999 (64 FR 31898), under title 40, part
63, subpart LLL of the CFR (40 CFR part 63, subpart LLL). The rule was
amended on April 5, 2002 (67 FR 16614); July 5, 2002 (67 FR 44766);
December 6, 2002 (67 FR 72580); December 20, 2006 (71 FR 76518);
September 9, 2010 (75 FR 54970); January 18, 2011 (76 FR 2832);
February 12, 2013 (78 FR 10006); July 27, 2015 (80 FR 44772); September
11, 2015 (80 FR 54728); and July 25, 2016 (81 FR 48356). The amendments
further defined affected cement kilns as those used to manufacture
Portland cement, except for kilns that burn hazardous waste, and are
subject to and regulated under 40 CFR part 63, subpart EEE, and kilns
that burn solid waste, which are subject to the CISWI rule under 40 CFR
part 60, subparts CCCC and DDDD. Additionally, onsite sources that are
subject to standards for nonmetallic mineral processing plants in 40
CFR part 60, subpart OOO are not subject to 40 CFR part 63, subpart
LLL. Crushers are not covered by 40 CFR part 63, subpart LLL regardless
of their location. Subpart LLL NESHAP regulates HAP emissions from new
and existing Portland cement production facilities that are major or
area sources of HAP, with one exception. Kilns located at facilities
that are area sources, are not regulated for hydrochloric acid (HCl)
emissions.
Portland cement manufacturing is an energy-intensive process in
which cement is made by grinding and heating a mixture of raw materials
such as limestone, clay, sand, and iron ore in a rotary kiln. The kiln
is a large furnace that is fueled by coal, oil, gas, coke, and/or
various waste materials. The product (known as clinker) from the kiln
is cooled, ground, and then mixed with a small amount of gypsum to
produce Portland cement.
The main source of air toxics emissions from a Portland cement
plant is the kiln. Emissions originate from the burning of fuels and
heating of feed materials. Air toxics are also emitted from the
grinding, cooling, and materials handling steps in the manufacturing
process. Pollutants regulated under the subpart LLL NESHAP are
particulate matter (PM) as a surrogate for non-mercury HAP metals,
total hydrocarbons (THC) as a surrogate for organic HAP other than
dioxins and furans (D/F), organic HAP as an alternative to the limit
for THC, mercury, HCl (from major sources only), and D/F expressed as
toxic equivalents (TEQ). The kiln is regulated for all HAP and raw
material dryers are regulated for THC or the alternative organic HAP.
Clinker coolers are regulated for PM. Finish mills and raw mills are
regulated for opacity. During periods of startup and shutdown, the
kiln, clinker cooler, and raw material dryer are regulated by work
practices. Open clinker storage piles are regulated by work practices.
The emission standards for the affected sources are summarized in Table
2.
Table 2--Emission Limits for Kilns, Clinker Coolers, Raw Material Dryers, Raw and Finish Mills
----------------------------------------------------------------------------------------------------------------
And the units
And the And it is Your emissions of the The oxygen
If your source is a (an): operating mode located at a: limits are: emissions limit correction
is: are: factor is:
----------------------------------------------------------------------------------------------------------------
1. Existing kiln............. Normal Major or area PM \1\ 0.07.... Pounds (lb)/ton NA.
operation. source. clinker.
[[Page 44259]]
D/F \2\ 0.2.... Nanograms/dry 7 percent.
standard cubic
meters (ng/
dscm) (TEQ).
Mercury 55..... lb/million (MM) NA.
tons clinker.
THC \3\ \4\ 24. Parts per 7 percent.
million,
volumetric dry
(ppmvd).
2. Existing kiln............. Normal Major source... HCl 3.......... ppmvd.......... 7 percent.
operation.
3. Existing kiln............. Startup and Major or area Work practices. NA............. NA.
shutdown. source. (63.1346(g))...
4. New kiln.................. Normal Major or area PM \1\ 0.02.... lb/ton clinker. NA.
operation. source.
D/F \2\ 0.2.... ng/dscm (TEQ).. 7 percent.
Mercury 21..... lb/MM tons NA.
clinker.
THC \3\ \4\ 24. ppmvd.......... 7 percent.
5. New kiln.................. Normal Major source... HCl 3.......... ppmvd.......... 7 percent.
operation.
6. New kiln.................. Startup and Major or area Work practices. NA............. NA.
shutdown. source. (63.1346(g))...
7. Existing clinker cooler... Normal Major or area PM 0.07........ lb/ton clinker. NA.
operation. source.
8. Existing clinker cooler... Startup and Major or area Work practices NA............. NA.
shutdown. source. (63.1348(b)(9)
).
9. New clinker cooler........ Normal Major or area PM 0.02........ lb/ton clinker. NA.
operation. source.
10. New clinker cooler....... Startup and Major or area Work practices NA............. NA.
shutdown. source. (63.1348(b)(9)
).
11. Existing or new raw Normal Major or area THC \3\ \4\ 24. ppmvd.......... NA.
material dryer. operation. source.
12. Existing or new raw Startup and Major or area Work practices NA............. NA.
material dryer. shutdown. source. (63.1348(b)(9)
).
13. Existing or new raw or All operating Major source... Opacity 10..... percent........ NA.
finish mill. modes.
----------------------------------------------------------------------------------------------------------------
\1\ The initial and subsequent PM performance tests are performed using Method 5 or 5I and consist of three test
runs.
\2\ If the average temperature at the inlet to the first PM control device (fabric filter or electrostatic
precipitator) during the D/F performance test is 400 [deg]F or less, this limit is changed to 0.40 ng/dscm
(TEQ).
\3\ Measured as propane.
\4\ Any source subject to the 24 ppmvd THC limit may elect to meet an alternative limit of 12 ppmvd for total
organic HAP.
C. What data collection activities were conducted to support this
action?
For the Portland Cement Manufacturing Industry source category, we
did not submit data collection requests to the industry or request
emissions testing by the industry for the information used in this
analysis. The data and data sources used to support this action are
described in section II.D below.
D. What other relevant background information and data are available?
For the Portland Cement Manufacturing Industry source category, a
comprehensive list of facilities and kilns was compiled using
information from the EPA's Greenhouse Gas Reporting Program (GHGRP)
(https://www.epa.gov/ghgreporting). All manufacturers of Portland
cement are required to report annually their greenhouse gas emissions
to the EPA (40 CFR part 98, subpart H). In reporting year 2015, 95
Portland cement facilities reported under the GHGRP. As explained above
in section II.B, kilns that are fueled by hazardous waste are subject
to the hazardous waste regulations in 40 CFR part 63, subpart EEE and,
therefore, are not subject to 40 CFR part 63, subpart LLL. Kilns that
are fueled by solid waste are subject to regulations in 40 CFR part 60,
subpart CCCC or DDDD and are also not subject to subpart LLL. To assist
in the identification of which sources are subject to subpart LLL, the
comprehensive list of Portland cement manufacturing facilities was
submitted to the Portland Cement Association (PCA) for review. The PCA
is an organization that represents the manufacturers of cement. The PCA
provided information on the status of each kiln and clinker cooler,
whether or not they were subject to subpart LLL regulations, and
identified other sources at facilities, such as raw material dryers,
that were also subject to subpart LLL.
The risk modeling dataset was developed in a two-step process.
Initially, a draft dataset was developed using available information on
emissions, stack parameters, and emission source locations. In step
two, the draft dataset for each Portland cement manufacturing facility
was submitted to the facility or its parent company to review for
accuracy. Based on the review by each company and the submittal of
documentation supporting the changes, the risk modeling dataset was
revised. Copies of the datasets sent to the companies for review and
the revised datasets and supporting documentation submitted by each
company are contained in the docket to this rulemaking (Docket ID No.
EPA-HQ-OAR-2016-0442).
The initial draft dataset was developed using emission test data to
the extent possible. Under 40 CFR part 63, subpart LLL, the EPA
requires that performance test results be submitted to the EPA via the
Compliance and Emissions Data Reporting Interface (CEDRI), which can be
accessed through the EPA's Central Data Exchange (CDX). Emissions data
are publicly available through the EPA's Web Factor Information
Retrieval System (WebFIRE) using the EPA's electronic reporting tool
(ERT) as listed on the EPA's ERT Web site (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert). To
estimate actual emissions, available emissions data were extracted from
each facility's submitted ERT file. When emissions data were not
available in ERT, the subpart LLL emissions limit was substituted as a
placeholder for actual emissions until the data set could be reviewed
and revised by industry.
III. Analytical Procedures
In this section, we describe the analyses performed to support the
proposed decisions for the RTR and other issues addressed in this
proposal.
[[Page 44260]]
A. How did we estimate post-MACT risks posed by the source category?
The EPA conducted a risk assessment that provides estimates of the
MIR posed by the HAP emissions from each source in the source category,
the hazard index (HI) for chronic exposures to HAP with the potential
to cause non-cancer health effects, and the hazard quotient (HQ) for
acute exposures to HAP with the potential to cause non-cancer health
effects. The assessment also provides estimates of the distribution of
cancer risks within the exposed populations, cancer incidence, and an
evaluation of the potential for adverse environmental effects. The
eight sections that follow this paragraph describe how we estimated
emissions and conducted the risk assessment. The docket for this
rulemaking contains the following document which provides more
information on the risk assessment inputs and models: Residual Risk
Assessment for the Portland Cement Manufacturing Industry Source
Category in Support of the Risk and Technology Review September, 2017
Proposed Rule. The methods used to assess risks (as described in the
eight primary steps below) are consistent with those peer-reviewed by a
panel of the EPA's Science Advisory Board (SAB) in 2009 and described
in their peer review report issued in 2010;\2\ they are also consistent
with the key recommendations contained in that report.
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\2\ U.S. EPA SAB. Risk and Technology Review (RTR) Risk
Assessment Methodologies: For Review by the EPA's Science Advisory
Board with Case Studies--MACT I Petroleum Refining Sources and
Portland Cement Manufacturing, May 2010.
---------------------------------------------------------------------------
1. How did we estimate actual emissions and identify the emissions
release characteristics?
The pollutants regulated under 40 CFR part 63, subpart LLL are PM,
HCl, THC, mercury, and D/F. The emission standards apply to Portland
cement plants that are major or area sources, with one exception. Kilns
that are located at a facility that is an area source are not subject
to the emission limits for HCl. Sources subject to the emissions limit
for THC may elect to meet an alternative limit for total organic HAP.
For purposes of subpart LLL, total organic HAP is the sum of the
concentrations of compounds of formaldehyde, benzene, toluene, styrene,
m-xylene, p-xylene, o-xylene, acetaldehyde, and naphthalene as measured
by EPA Test Method 320 or Method 18 of appendix A to 40 CFR part 63 or
ASTM D6348-03 or a combination of these methods, as appropriate. The
affected sources at Portland cement plants that were accounted for in
the risk modeling dataset include the kiln, as well as any alkali
bypass or inline raw mill or inline coal mill, clinker coolers, and raw
material dryers. Kilns fueled with hazardous waste or solid waste and
not subject to subpart LLL were excluded from the dataset. All affected
sources in the risk modeling dataset emit through stacks. As mentioned
in section II.D above, the risk modeling dataset used for estimating
actual emissions was developed in a two-step process. Initially, the
dataset was developed using available information and is described
below. The dataset for each Portland cement manufacturing facility was
then submitted to the facility, or its parent company, to review for
accuracy. Based on the review by each company, and the submittal of
documentation supporting the changes, the risk modeling dataset was
then revised. Copies of the datasets sent to the companies for review
and the revised datasets submitted by each company are contained in the
docket to this rulemaking (Docket ID No. EPA-HQ-OAR-2016-0442).
As described in section II.D above, available emissions data were
extracted from each facility's submitted ERT file. To ensure that the
emissions data reflect process and control device changes made at each
Portland cement plant to comply with the 2013 final amendments to 40
CFR part 63, subpart LLL (February 12, 2013, 78 FR 10006), emissions
data from mid-2015 and later were used as inputs into the emissions
modeling file.
Emissions data are reported in ERT in units of pounds per hour (lb/
hr), which were multiplied by a facility's reported annual hours of
operation to calculate emissions in tpy. If hours of operation were not
reported, the default of 8,760 hours per year was used. When emissions
data were not available in ERT, the 40 CFR part 63, subpart LLL
emissions limit was substituted as a placeholder for actual emissions
until the data set could be reviewed and revised by industry.
Subpart LLL of 40 CFR part 63 uses PM as a surrogate for non-
mercury metallic HAP and THC as a surrogate for organic HAP. The
specific non-mercury metallic HAP that went into the modeling file are
antimony, arsenic, beryllium, cadmium, chromium, cobalt, lead,
manganese, mercury, nickel, and selenium. As an alternative to
measuring THC, subpart LLL allows sources to measure directly their
emissions of the nine organic HAP listed in subpart LLL. The specific
organic HAP that went into the modeling file are acetaldehyde,
formaldehyde, naphthalene, styrene, toluene, m-xylene, o-xylene, p-
xylene, and benzene. Because subpart LLL compliance testing is
typically performed for the surrogates PM and THC, there are limited
test data available for compound-specific non-mercury metallic and
organic HAP emissions. To generate compound-specific metallic HAP and
organic HAP emissions estimates, recent emissions tests were identified
in which testing was done for compound-specific metallic and organic
HAP emissions. To account for recent changes in emission controls and
production processes that have been implemented by facilities to comply
with the subpart LLL MACT standards, emissions testing that occurred in
2015 and later were used to develop compound-specific estimates for
metallic HAP and organic HAP emissions. In the case of D/F, the subpart
LLL emission limits for D/F were unchanged in the 2013 final rule.
Thus, older D/F test data could be used along with more recent test
data.
The approach used to develop the final risk modeling dataset
assures the quality of the data at various steps in the process of
developing the dataset. The initial step in developing the dataset was
to compile a list of affected facilities. A comprehensive list of
cement manufacturing facilities and kilns was derived from the EPA's
GHGRP, which requires reporting by all cement manufacturing facilities.
Not all Portland cement kilns are subject to 40 CFR part 63, subpart
LLL. Kilns that burn commercial and industrial solid waste are subject
to 40 CFR part 60, subpart CCCC and DDDD. Kilns that burn hazardous
waste are subject to 40 CFR part 63, subpart EEE. To help identify the
cement kilns that are subject to subpart LLL regulations, the list of
facilities and kilns was submitted to the PCA for review. In their
review, they provided useful information on which cement manufacturing
facilities were or were not subject to subpart LLL, whether kilns and
clinker coolers used separate or combined stacks, the presence of
additional affected sources not on the initial list, and the presence
of kilns that were not currently operating. For those kilns identified
as not currently operating, the appropriate state permitting agency was
contacted to determine whether the kiln was currently permitted to
operate. If the kiln was not operating, but retained their title V
permit, they were kept in the dataset. In other instances, company
representatives were contacted to verify that kilns at their facilities
were or were
[[Page 44261]]
not subject to subpart LLL regulations. In developing the emissions
data, operating hours, stack parameters (i.e., stack height,
temperature, diameter, velocity, and flowrate), and stack locations
(i.e., latitude and longitude), the use of the EPA's ERT provides a
single source of electronic test data and replaces the manual
collection and evaluation of test data. The regulated facility owner or
operator submits their summary report semiannually to the EPA via the
CEDRI, which is accessed through the EPA's CDX (www.epa.gov/cdx). This
electronic submission of data helps to ensure that information and
procedures required by test methods are documented, provides consistent
criteria to quantitatively characterize the quality of the data
collected during the emissions test, and standardizes the reporting of
results. Information on stack parameters and stack locations were also
derived from ERT. For facilities that had not yet submitted their test
information to ERT, the emission limits were used as placeholders until
industry could review the information. When operating hours were not in
ERT, a placeholder of 8,760 hours was used until industry could review
the information. When stack parameters and stack locations were not in
ERT, other sources of information such as the 2013 Universal Industrial
Sectors Integrated Solutions (UISIS) modeling file created by the EPA
and the 2011 National Emissions Inventory (NEI) were used. As a check
on the emissions data, operating hours, stack parameters, and stack
locations compiled for each facility, a draft of the dataset consisting
of the data for all the facilities under a single company was sent to a
representative at the appropriate company for review. Instructions for
reviewing and making changes to the dataset required that any revisions
be supported with appropriate documentation. In addition, example
calculations for emissions estimates and default stack parameters were
provided. Revisions made to the data for each facility were
incorporated into a master final dataset. The master final dataset was
subjected to further quality evaluation. For example, exhaust gas
flowrates were checked using information on stack diameters and gas
velocities. Stack diameters and stack velocities are checked for
outliers. Stack locations were also checked using Google Earth[supreg]
to ensure that stack locations were correctly located at the cement
manufacturing facility.
The derivation of actual emission estimates is discussed in more
detail in the document, Development of the RTR Risk Modeling Dataset
for the Portland Cement Manufacturing Industry Source Category, which
is available in the docket for this proposed rulemaking.
2. How did we estimate MACT-allowable emissions?
The available emissions data in the RTR emissions dataset include
estimates of the mass of HAP emitted during the specified annual time
period. In some cases, these ``actual'' emission levels are lower than
the emission levels required to comply with the current MACT standards.
The emissions level allowed to be emitted by the MACT standards is
referred to as the ``MACT-allowable'' emissions level. We discussed the
use of both MACT-allowable and actual emissions in the final Coke Oven
Batteries RTR (70 FR 19998-19999, April 15, 2005) and in the proposed
and final Hazardous Organic NESHAP RTRs (71 FR 34428, June 14, 2006,
and 71 FR 76609, December 21, 2006, respectively). In those actions, we
noted that assessing the risks at the MACT-allowable level is
inherently reasonable since these risks reflect the maximum level
facilities could emit and still comply with national emission
standards. We also explained that it is reasonable to consider actual
emissions, where such data are available, in both steps of the risk
analysis, in accordance with the Benzene NESHAP approach (54 FR 38044,
September 14, 1989).
Allowable emissions are calculated using the emission limits in the
rule for existing sources along with the emission factors for metallic
HAP, organic HAP, and D/F congeners, the annual production capacity,
and, when the emission limit is a concentration-based limit, the annual
hours of operation reported by each source. We note that these are
conservative estimates of allowable emissions. It is unlikely that
emissions would be at the maximum limit at all times because sources
cannot emit HAP at a level that is exactly equal to the limit and
remain in compliance with the standard due to day-to-day variability in
process operations and emissions. On average, facilities must emit at
some level below the MACT limit to ensure that they are always in
compliance. The derivation of allowable emissions is discussed in more
detail in the document, Development of the RTR Risk Modeling Dataset
for the Portland Cement Manufacturing Industry Source Category, which
is available in the docket for this proposed rulemaking.
3. How did we conduct dispersion modeling, determine inhalation
exposures, and estimate individual and population inhalation risks?
Both long-term and short-term inhalation exposure concentrations
and health risks from the source category addressed in this proposal
were estimated using the Human Exposure Model (Community and Sector
HEM-3). The HEM-3 performs three primary risk assessment activities:
(1) conducting dispersion modeling to estimate the concentrations of
HAP in ambient air, (2) estimating long-term and short-term inhalation
exposures to individuals residing within 50 kilometers (km) of the
modeled sources,\3\ and (3) estimating individual and population-level
inhalation risks using the exposure estimates and quantitative dose-
response information.
---------------------------------------------------------------------------
\3\ This metric comes from the Benzene NESHAP. See 54 FR 38046,
September 14, 1989.
---------------------------------------------------------------------------
The air dispersion model used by the HEM-3 model (AERMOD) is one of
the EPA's preferred models for assessing pollutant concentrations from
industrial facilities.\4\ To perform the dispersion modeling and to
develop the preliminary risk estimates, HEM-3 draws on three data
libraries. The first is a library of meteorological data, which is used
for dispersion calculations. This library includes 1 year (2016) of
hourly surface and upper air observations for more than 800
meteorological stations, selected to provide coverage of the U.S. and
Puerto Rico. A second library of U.S. Census Bureau census block \5\
internal point locations and populations provides the basis of human
exposure calculations (U.S. Census, 2010). In addition, for each census
block, the census library includes the elevation and controlling hill
height, which are also used in dispersion calculations. A third library
of pollutant unit risk factors and other health benchmarks is used to
estimate health risks. These risk factors and health benchmarks are the
latest values recommended by the EPA for HAP and other toxic air
pollutants. These values are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants and are discussed in more detail later in this
section.
---------------------------------------------------------------------------
\4\ U.S. EPA. Revision to the Guideline on Air Quality Models:
Adoption of a Preferred General Purpose (Flat and Complex Terrain)
Dispersion Model and Other Revisions (70 FR 68218, November 9,
2005).
\5\ A census block is the smallest geographic area for which
census statistics are tabulated.
---------------------------------------------------------------------------
In developing the risk assessment for chronic exposures, we used
the
[[Page 44262]]
estimated annual average ambient air concentrations of each HAP emitted
by each source for which we have emissions data in the source category.
The air concentrations at each nearby census block centroid were used
as a surrogate for the chronic inhalation exposure concentration for
all the people who reside in that census block. We calculated the MIR
for each facility as the cancer risk associated with a continuous
lifetime (24 hours per day, 7 days per week, and 52 weeks per year for
a 70-year period) exposure to the maximum concentration at the centroid
of inhabited census blocks. Individual cancer risks were calculated by
multiplying the estimated lifetime exposure to the ambient
concentration of each of the HAP (in micrograms per cubic meter ([mu]g/
m\3\)) by its unit risk estimate (URE). The URE is an upper bound
estimate of an individual's probability of contracting cancer over a
lifetime of exposure to a concentration of 1 microgram of the pollutant
per cubic meter of air. For residual risk assessments, we generally use
URE values from the EPA's Integrated Risk Information System (IRIS).
For carcinogenic pollutants without IRIS values, we look to other
reputable sources of cancer dose-response values, often using
California EPA (CalEPA) URE values, where available. In cases where
new, scientifically credible dose response values have been developed
in a manner consistent with the EPA guidelines and have undergone a
peer review process similar to that used by the EPA, we may use such
dose-response values in place of, or in addition to, other values, if
appropriate.
The EPA estimated incremental individual lifetime cancer risks
associated with emissions from the facilities in the source category as
the sum of the risks for each of the carcinogenic HAP (including those
classified as carcinogenic to humans, likely to be carcinogenic to
humans, and suggestive evidence of carcinogenic potential \6\) emitted
by the modeled sources. Cancer incidence and the distribution of
individual cancer risks for the population within 50 km of the sources
were also estimated for the source category as part of this assessment
by summing individual risks. A distance of 50 km is consistent with
both the analysis supporting the 1989 Benzene NESHAP (54 FR 38044,
September 14, 1989) and the limitations of Gaussian dispersion models,
including AERMOD.
---------------------------------------------------------------------------
\6\ These classifications also coincide with the terms ``known
carcinogen, probable carcinogen, and possible carcinogen,''
respectively, which are the terms advocated in the EPA's previous
Guidelines for Carcinogen Risk Assessment, published in 1986 (51 FR
33992, September 24, 1986). In August 2000, the document,
Supplemental Guidance for Conducting Health Risk Assessment of
Chemical Mixtures (EPA/630/R-00/002) was published as a supplement
to the 1986 document. Copies of both documents can be obtaine