[Federal Register Volume 85, Number 156 (Wednesday, August 12, 2020)]
[Rules and Regulations]
[Pages 49084-49167]
[FR Doc No: 2020-12776]

Vol. 85

Wednesday,

No. 156

August 12, 2020

Part III

 Environmental Protection Agency

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40 CFR Part 63

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National Emission Standards for Hazardous Air Pollutants: Miscellaneous
Organic Chemical Manufacturing Residual Risk and Technology Review;
Final Rule

Federal Register / Vol. 85, No. 156 / Wednesday, August 12, 2020 /
Rules and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2018-0746; FRL-10010-27-OAR]
RIN 2060-AT85

National Emission Standards for Hazardous Air Pollutants:
Miscellaneous Organic Chemical Manufacturing Residual Risk and
Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action finalizes the residual risk and technology review
(RTR) conducted for the Miscellaneous Organic Chemical Manufacturing
source category regulated under national emission standards for
hazardous air pollutants (NESHAP). The U.S. Environmental Protection
Agency (EPA) is finalizing decisions concerning the RTR, including
amendments pursuant to the technology review for equipment leaks and
heat exchange systems, and also amendments pursuant to the risk review
to specifically address ethylene oxide emissions from storage tanks,
process vents, and equipment leaks. In addition, we are taking final
action to correct and clarify regulatory provisions related to
emissions during periods of startup, shutdown, and malfunction (SSM),
including removing general exemptions for periods of SSM, adding work
practice standards for periods of SSM where appropriate, and clarifying
regulatory provisions for certain vent control bypasses. The EPA is
also taking final action to add monitoring and operational requirements
for flares that control ethylene oxide emissions and flares used to
control emissions from processes that produce olefins and polyolefins;
add provisions for electronic reporting of performance test results and
other reports; and include other technical corrections to improve
consistency and clarity. We estimate that these final amendments will
reduce hazardous air pollutants (HAP) emissions from this source
category by approximately 107 tons per year (tpy) and reduce ethylene
oxide emissions from this source category by approximately 0.76 tpy. We
also estimate that these final amendments will reduce excess emissions
of HAP from flares that control ethylene oxide emissions and flares
used to control emissions from processes that produce olefins and
polyolefins by an additional 263 tpy.

DATES: This final rule is effective on August 12, 2020. The
incorporation by reference (IBR) of certain publications listed in the
rule is approved by the Director of the Federal Register as of August
12, 2020.

ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2018-0746. All documents in the docket are
listed on the https://www.regulations.gov/ website. Although listed,
some information is not publicly available, e.g., Confidential Business
Information or other information whose disclosure is restricted by
statute. Certain other material, such as copyrighted material, is not
placed on the internet and will be publicly available only in hard copy
form. Publicly available docket materials are available electronically
through https://www.regulations.gov/. Out of an abundance of caution
for members of the public and our staff, the EPA Docket Center and
Reading Room was closed to public visitors on March 31, 2020, to reduce
the risk of transmitting COVID-19. Our Docket Center staff will
continue to provide remote customer service via email, phone, and
webform. There is a temporary suspension of mail delivery to the EPA,
and no hand deliveries are currently accepted. For further information
and updates on EPA Docket Center services and the current status,
please visit us online at https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: For questions about this final action,
contact Ms. Tegan Lavoie, Sector Policies and Programs Division (E-143-
01), Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina 27711;
telephone number:<PHONE_NUMBER>; and email address:
<EMAIL_ADDRESS>For specific information regarding the risk
modeling methodology, contact Mr. Matthew Woody, 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:<PHONE_NUMBER>;
and email address<EMAIL_ADDRESS>For information about the
applicability of the NESHAP to a particular entity, contact Mr. John
Cox, Office of Enforcement and Compliance Assurance, U.S. Environmental
Protection Agency, WJC South Building, 1200 Pennsylvania Ave. NW,
Washington, DC 20460; telephone number:<PHONE_NUMBER>; and email
address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:
    Preamble acronyms and abbreviations. We use multiple acronyms and
terms in this preamble. While this list may not be exhaustive, to ease
the reading of this preamble and for reference purposes, the EPA
defines the following terms and acronyms here:

ACC American Chemistry Council
AEGL acute exposure guideline level
APCD air pollution control device
AMEL Alternative means of emission limitation
ANSI American National Standards Institute
BAAQMD Bay Area Air Quality Management District
Btu/scf British thermal unit per standard cubic foot
CAA Clean Air Act
CAP Chemical Accident Prevention
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CEMS continuous emissions monitoring systems
CFR Code of Federal Regulations
CRA Congressional Review Act
EPA Environmental Protection Agency
EPCRA Emergency Planning and Community Right-To-Know Act
ERT Electronic Reporting Tool
FID flame ionization detector
FTIR fourier transfer infrared spectrometry
gpm gallons per minute
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HES heat exchanger systems
HI hazard index
HON Hazardous Organic NESHAP
HQ hazard quotient
HRVOC highly reactive volatile organic compounds
IBR incorporation by reference
ICR Information Collection Request
IRIS Integrated Risk Information System
kg/yr kilograms per year
km kilometers
lb/yr pounds per year
LDAR leak detection and repair
LEL lower explosive limit
MACT maximum achievable control technology
MCPU miscellaneous organic chemical manufacturing process unit
MIR maximum individual risk
MON Miscellaneous Organic Chemical Manufacturing NESHAP
NAICS North American Industry Classification System
NEI National Emissions Inventory
NESHAP national emission standards for hazardous air pollutants
NHVcz net heating value of the combustion zone gas
NRDC Natural Resources Defense Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
OMB Office of Management and Budget
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PDF portable document format
PDH propane dehydrogenation

PFTIR passive fourier transfer infrared spectrometry
POM polycyclic organic matter
ppm parts per million
ppmv parts per million by volume
ppmw parts per million by weight
PRA Paperwork Reduction Act
PRD pressure relief device(s)
psig pounds per square inch gauge
PSM Process Safety Management
RACT reasonably available control technology
REL reference exposure level
RFA Regulatory Flexibility Act
RTR residual risk and technology review
SCAQMD South Coast Air Quality Management District
SSM startup, shutdown, and malfunction
SV screening value
TAC Texas Administrative Code
TCEQ Texas Commission on Environmental Quality the Court United
States Court of Appeals for the District of Columbia Circuit
TOC total organic compound
TOSHI target organ-specific hazard index
tpy tons per year
TRI Toxics Release Inventory
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
VCS voluntary consensus standards
VOC volatile organic compound(s)

    Background information. On December 17, 2019 (84 FR 69182), the EPA
proposed revisions to the Miscellaneous Organic Chemical Manufacturing
NESHAP (MON) based on our RTR. In this action, we are finalizing
decisions and revisions for the rule. We summarize some of the more
significant comments we timely received regarding the proposed rule and
provide our responses in this preamble. A summary of all other public
comments on the proposal and the EPA's responses to those comments is
available in the Summary of Public Comments and Responses for the Risk
and Technology Review for Miscellaneous Organic Chemical Manufacturing,
in Docket ID No. EPA-HQ-OAR-2018-0746. A ``tracked changes'' version of
the regulatory language that incorporates the changes in this action is
available in the docket.
    Organization of this document. The information in this preamble is
organized as follows:

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related
information?
    C. Judicial Review and Administrative Reconsideration
II. Background
    A. What is the statutory authority for this action?
    B. What is the Miscellaneous Organic Chemical Manufacturing
source category and how does the NESHAP regulate HAP emissions from
the source category?
    C. What changes did we propose for the Miscellaneous Organic
Chemical Manufacturing source category in our December 17, 2019, RTR
proposal?
III. What is included in this final rule?
    A. What are the final rule amendments based on the risk review
for the Miscellaneous Organic Chemical Manufacturing source
category?
    B. What are the final rule amendments based on the technology
review for the Miscellaneous Organic Chemical Manufacturing source
category?
    C. What are the final rule amendments pursuant to CAA section
112(d)(2) and (3) and 112(h) for the Miscellaneous Organic Chemical
Manufacturing source category?
    D. What are the final rule amendments addressing emissions
during periods of SSM?
    E. What other changes have been made to the NESHAP?
    F. What are the effective and compliance dates of the standards?
IV. What is the rationale for our final decisions and amendments for
the Miscellaneous Organic Chemical Manufacturing source category?
    A. Residual Risk Review for the Miscellaneous Organic Chemical
Manufacturing Source Category
    B. Technology Review for the Miscellaneous Organic Chemical
Manufacturing Source Category
    C. Amendments Pursuant to CAA section 112(d)(2) and (3) and
112(h) for the Miscellaneous Organic Chemical Manufacturing Source
Category
    D. Amendments Addressing Emissions During Periods of SSM
    E. Other Amendments to the MACT Standards
V. Summary of Cost, Environmental, and Economic Impacts and
Additional Analyses Conducted
    A. What are the affected facilities?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
    F. What analysis of environmental justice did we conduct?
    G. What analysis of children's environmental health did we
conduct?
VI. Statutory and Executive Order Reviews
    A. Executive Orders 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 13771: Reducing Regulations and Controlling
Regulatory Costs
    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    H. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act (NTTAA) and
1 CFR Part 51
    K. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
    L. Congressional Review Act (CRA)

I. General Information

A. Does this action apply to me?

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

 Table 1--NESHAP and Industrial Source Categories Affected by This Final
                                 Action
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       NESHAP and Source Category                 NAICS \1\ code
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Miscellaneous Organic Chemical           3251, 3252, 3253, 3254, 3255,
 Manufacturing.                           3256, and 3259, with several
                                          exceptions.
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\1\ North American Industry Classification System.

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

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

    In addition to being available in the docket, an electronic copy of
this final action will also be available on the internet. Following
signature by the

EPA Administrator, the EPA will post a copy of this final action at:
https://www.epa.gov/stationary-sources-air-pollution/miscellaneous-organic-chemical-manufacturing-national-emission. Following publication
in the Federal Register, the EPA will post the Federal Register version
and key technical documents at this same website.
    Additional information is available on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/risk-and-technology-review-national-emissions-standards-hazardous. This information
includes an overview of the RTR program and links to project websites
for the RTR source categories.

C. Judicial Review and Administrative Reconsideration

    Under Clean Air Act (CAA) section 307(b)(1), judicial review of
this final action is available only by filing a petition for review in
the United States Court of Appeals for the District of Columbia Circuit
(the Court) by October 13, 2020. Under CAA section 307(b)(2), the
requirements established by this final rule may not be challenged
separately in any civil or criminal proceedings brought by the EPA to
enforce the requirements.
    Section 307(d)(7)(B) of the CAA further provides that only an
objection to a rule or procedure which was raised with reasonable
specificity during the period for public comment (including any public
hearing) may be raised during judicial review. This section also
provides a mechanism for the EPA to reconsider the rule if the person
raising an objection can demonstrate to the Administrator that it was
impracticable to raise such objection within the period for public
comment or if the grounds for such objection arose after the period for
public comment (but within the time specified for judicial review) and
if such objection is of central relevance to the outcome of the rule.
Any person seeking to make such a demonstration should submit a
Petition for Reconsideration to the Office of the Administrator, U.S.
EPA, Room 3000, WJC South Building, 1200 Pennsylvania Ave. NW,
Washington, DC 20460, with a copy to both the person(s) listed in the
preceding FOR FURTHER INFORMATION CONTACT section, and the Associate
General Counsel for the Air and Radiation Law Office, Office of General
Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave. NW,
Washington, DC 20460.

II. Background

A. What is the statutory authority for this action?

    On March 13, 2017, the U.S. District Court for District of Columbia
ordered the EPA to perform all acts or duties required by CAA section
112(f)(2) and CAA section 112(d)(6) for 20 source categories, including
Miscellaneous Organic Chemical Manufacturing, within three years of the
date of the court order (See California Communities Against Toxics, et
al. v. Scott Pruitt, 241 F. Supp. 3d 199 (D.D.C. 2017)). On February
19, 2020, the U.S. District Court for District of Columbia granted the
EPA an extension on the final rule deadline for the Miscellaneous
Organic Chemical Manufacturing source category from March 13, 2020, to
May 29, 2020.
    Section 112 of the CAA establishes a two-stage regulatory process
to address emissions of HAP from stationary sources. In the first
stage, we must identify categories of sources emitting one or more of
the HAP listed in CAA section 112(b) and then promulgate technology-
based NESHAP for those sources. ``Major sources'' are those that emit,
or have the potential to emit, any single HAP at a rate of 10 tons per
year (tpy) or more, or 25 tpy or more of any combination of HAP. For
major sources, these standards are commonly referred to as maximum
achievable control technology (MACT) standards and must reflect the
maximum degree of emission reductions of HAP achievable (after
considering cost, energy requirements, and non-air quality health and
environmental impacts). In developing MACT standards, CAA section
112(d)(2) directs the EPA to consider the application of measures,
processes, methods, systems, or techniques, including, but not limited
to those that reduce the volume of or eliminate HAP emissions through
process changes, substitution of materials, or other modifications;
enclose systems or processes to eliminate emissions; collect, capture,
or treat HAP when released from a process, stack, storage, or fugitive
emissions point; are design, equipment, work practice, or operational
standards; or any combination of the above.
    For MACT standards, the statute specifies certain minimum
stringency requirements, which are referred to as MACT floor
requirements, and which may not be based on cost considerations. See
CAA section 112(d)(3). For new sources, the MACT floor cannot be less
stringent than the emission control achieved in practice by the best-
controlled similar source. The MACT standards for existing sources can
be less stringent than standards for new sources, but they cannot be
less stringent than the average emission limitation achieved by the
best-performing 12 percent of existing sources in the category or
subcategory (or the best-performing five sources for categories or
subcategories with fewer than 30 sources). In developing MACT
standards, we must also consider control options that are more
stringent than the floor under CAA section 112(d)(2). We may establish
standards more stringent than the floor, after consideration of the
cost of achieving the emissions reductions, any non-air quality health
and environmental impacts, and energy requirements.
    In the second stage of the regulatory process, the CAA requires the
EPA to undertake two different analyses, which we refer to as the
technology review and the residual risk review. Under the technology
review, we must review the technology-based standards and revise them
``as necessary (taking into account developments in practices,
processes, and control technologies)'' no less frequently than every 8
years, pursuant to CAA section 112(d)(6). Under the residual risk
review, we must evaluate the risk to public health remaining after
application of the technology-based standards and revise the standards,
if necessary, to provide an ample margin of safety to protect public
health or to prevent, taking into consideration costs, energy, safety,
and other relevant factors, an adverse environmental effect. The
residual risk review is required within 8 years after promulgation of
the technology-based standards, pursuant to CAA section 112(f). In
conducting the residual risk review, if the EPA determines that the
current standards provide an ample margin of safety to protect public
health, it is not necessary to revise the MACT standards pursuant to
CAA section 112(f).\1\ For more information on the statutory authority
for this rule, see 84 FR 69182, December 17, 2019.
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    \1\ The Court has affirmed this approach of implementing CAA
section 112(f)(2)(A): NRDC v. EPA, 529 F.3d 1077, 1083 (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.'').
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B. What is the Miscellaneous Organic Chemical Manufacturing source
category and how does the NESHAP regulate HAP emissions from the source
category?

    The EPA promulgated the current NESHAP, herein called the
Miscellaneous Organic Chemical

Manufacturing NESHAP (MON) on November 10, 2003 (68 FR 63852), and
further amended the MON on July 1, 2005 (70 FR 38562), and July 14,
2006 (71 FR 40316). The standards are codified at 40 Code of Federal
Regulations (CFR) part 63, subpart FFFF. The MON regulates HAP
emissions from miscellaneous organic chemical manufacturing process
units (MCPUs) located at major sources. An MCPU includes a
miscellaneous organic chemical manufacturing process, as defined in 40
CFR 63.2550(i), and must meet the following criteria: (1) It
manufactures any material or family of materials described in 40 CFR
63.2435(b)(1); (2) it processes, uses, or generates any of the organic
HAP described in 40 CFR 63.2435(b)(2); and, (3) except for certain
process vents that are part of a chemical manufacturing process unit,
as identified in 40 CFR 63.100(j)(4), the MCPU is not an affected
source or part of an affected source under another subpart of 40 CFR
part 63. An MCPU also includes any assigned storage tanks and transfer
racks; equipment in open systems that is used to convey or store water
having the same concentration and flow characteristics as wastewater;
and components such as pumps, compressors, agitators, pressure relief
devices (PRDs), sampling connection systems, open-ended valves or
lines, valves, connectors, and instrumentation systems that are used to
manufacture any material or family of materials described in 40 CFR
63.2435(b)(1). Sources of HAP emissions regulated by the MON include
the following: process vents, storage tanks, transfer racks, equipment
leaks, wastewater streams, and heat exchange systems.
    As of November 6, 2018, there were 201 miscellaneous organic
chemical manufacturing facilities identified and in operation and
subject to the MON standards, herein referred to as ``MON facilities.''
This facility population count was developed using methods described in
section II.C of the proposal preamble (84 FR 69182, December 17, 2019).
A complete list of known MON facilities is available in Appendix 1 of
the document, Residual Risk Assessment for the Miscellaneous Organic
Chemical Manufacturing Source Category in Support of the 2019 Risk and
Technology Review Proposed Rule, which is available in the docket for
this rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-0011).

C. What changes did we propose for the Miscellaneous Organic Chemical
Manufacturing source category in our December 17, 2019, RTR proposal?

    On December 17, 2019, the EPA published a proposed rule in the
Federal Register for the MON, 40 CFR part 63, subpart FFFF, that took
into consideration the RTR analyses (84 FR 69182). We proposed to find
that the risks from the source category are unacceptable. We proposed
to address risk by revising the MON pursuant to CAA section 112(f)(2)
to require control of ethylene oxide emissions from process vents,
storage tanks, and equipment ``in ethylene oxide service.'' \2\ We also
proposed that these control requirements would both achieve acceptable
risks and provide an ample margin of safety to protect public health
and more stringent standards are not necessary to prevent an adverse
environmental effect.
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    \2\ For process vents, we proposed to define ``in ethylene oxide
service'' to mean that each batch and continuous process vent in a
process that, when uncontrolled, contains a concentration of greater
than or equal to 1 ppmv undiluted ethylene oxide, and when combined,
the sum of all these process vents would emit uncontrolled,
undiluted ethylene oxide emissions greater than or equal to 5 lb/yr
(2.27 kg/yr). For storage tanks of any capacity and vapor pressure,
we proposed to define ``in ethylene oxide service'' to mean that the
concentration of ethylene oxide of the stored liquid is greater than
or equal to 1 part per million by weight (ppmw). We proposed that
the exemptions for ``vessels storing organic liquids that contain
HAP only as impurities'' and ``pressure vessels designed to operate
in excess of 204.9 kilopascals and without emissions to the
atmosphere'' listed in the definition of ``storage tank'' at 40 CFR
63.2550(i) do not apply for storage tanks in ethylene oxide service.
For the ethylene oxide equipment leak provisions, we proposed to
define ``in ethylene oxide service'' to mean any equipment that
contains or contacts a fluid (liquid or gas) that is at least 0.1
percent by weight of ethylene oxide.
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    For process vents, we proposed to either reduce emissions of
ethylene oxide by (1) venting emissions through a closed-vent system to
a control device that reduces ethylene oxide by greater than or equal
to 99.9 percent by weight, to a concentration less than 1 part per
million by volume (ppmv) for each process vent, or to less than 5
pounds per year (lb/yr) for all combined process vents; or (2) venting
emissions through a closed-vent system to a flare meeting the proposed
flare operating requirements. For storage tanks, we proposed to reduce
emissions of ethylene oxide by either (1) venting emissions through a
closed-vent system to a control device that reduces ethylene oxide by
greater than or equal to 99.9 percent by weight or to a concentration
less than 1 ppmv for each storage tank vent; or (2) venting emissions
through a closed-vent system to a flare meeting the proposed flare
operating requirements. We proposed removing the option to allow use of
a design evaluation in lieu of performance testing to demonstrate
compliance for both process vents and storage tanks in ethylene oxide
service. We also proposed that owners or operators that choose to
control emissions with a non-flare control device conduct an initial
performance test on each control device in ethylene oxide service to
verify performance at the required level of control, and we proposed
conducting periodic performance testing on non-flare control devices in
ethylene oxide service every 5 years.
    To reduce risks from leaking equipment in ethylene oxide service,
we co-proposed two options, i.e., Control Option 1 and Control Option
2. In equipment leak co-proposed Control Option 1, we proposed that all
light liquid pumps in ethylene oxide service be monitored monthly at a
leak definition of 1,000 parts per million (ppm), and when a leak is
detected, it be repaired as soon as practicable, but not later than 15
calendar days after it is detected. Additionally, under co-proposed
Control Option 1, we proposed that the leak repair exemption available
for pumps at 40 CFR 63.1026(b)(3), 40 CFR 63.163(c)(3), and 40 CFR
65.107(b)(3) would not apply to equipment in ethylene oxide service.
Also, as part of co-proposed Control Option 1, we proposed that all
gas/vapor and light liquid connectors in ethylene oxide service be
monitored annually at a leak definition of 500 ppm, and when a leak is
detected, it be repaired as soon as practicable, but not later than 15
calendar days after it is detected. In equipment leak co-proposed
Control Option 2, we proposed that more stringent equipment leak
standards would apply to the facilities with a maximum individual risk
(MIR) greater than 100-in-1 million after imposition of the proposed
standards for process vents and storage tanks, as determined by this
risk analysis (i.e., Lanxess Corporation and Huntsman Performance). For
these two facilities, pumps in ethylene oxide service would be required
to be leakless (i.e., have zero emissions) and monitored annually to
verify there are no emissions. Additionally, valves in ethylene oxide
service would be required to either be leakless and monitored annually
or not be leakless and be monitored quarterly. For pumps and valves in
ethylene oxide service, we proposed that equipment is considered
leaking if an instrument reading above background is found.
Furthermore, at

the two higher risk facilities with a MIR greater than 100-in-1
million, we proposed that connectors in ethylene oxide service would be
monitored monthly at a leak definition of 100 ppm. We proposed that
when a leak is detected it would be repaired as soon as practicable,
but not later than 15 calendar days after it is detected, and a first
attempt at repair be made no later than 5 calendar days after the leak
is detected. As part of co-proposed Control Option 2, all other
facilities with MON equipment in ethylene oxide service would be
subject to the standards previously described in equipment leak co-
proposed Control Option 1.
    In addition, pursuant to the technology review for the
Miscellaneous Organic Chemical Manufacturing source category, we
proposed that no revisions to the current standards are necessary for
process vents, storage tanks, transfer racks, and wastewater streams;
however, we did propose changes for equipment leaks and heat exchange
systems. We proposed revisions to the equipment leak requirements,
pursuant to CAA section 112(d)(6), to lower the leak definition for
pumps in light liquid service at existing batch processes from 10,000
ppmv to 1,000 ppmv with monthly monitoring and clarify that you must
initially monitor for leaks within 30 days after initial startup of the
equipment. In addition, we proposed revisions to the heat exchange
system requirements, pursuant to CAA section 112(d)(6), to require
owners or operators to use the Modified El Paso Method and repair leaks
of total strippable hydrocarbon concentration (as methane) in the
stripping gas of 6.2 ppmv or greater.
    We also proposed the following amendments:
     Revisions to the operating and monitoring requirements for
flares that control ethylene oxide emissions, flares used to control
emissions from processes that produce olefins and polyolefins, and
providing the option for an owner or operator of a flare outside of
this subset to choose to opt in to these revised requirements in lieu
of complying with the current flare standards, pursuant to CAA section
112(d)(2) and (3);
     Requirements and clarifications for periods of SSM and
bypasses, including for PRD releases, bypass lines on closed vent
systems, maintenance activities, and certain gaseous streams routed to
a fuel gas system, pursuant to CAA section 112(d)(2) and (3);
     Revisions to the SSM provisions of the MON (in addition to
those related to vent control bypasses) in order to ensure that they
are consistent with the Court decision in Sierra Club v. EPA, 551 F. 3d
1019 (D.C. Cir. 2008), which vacated two provisions that exempted
source owners or operators from the requirement to comply with
otherwise applicable CAA section 112(d) emission standards during
periods of SSM;
     A requirement for electronic submittal of performance test
results and reports, performance evaluation reports, and compliance
reports;
     Clarifications to the requirements for nonregenerative
adsorbers, and regenerative adsorbers that are regenerated offsite;
     IBR of an alternative test method for EPA Method 18 (with
caveats);
     IBR of an alternative test method for EPA Method 101A and
EPA Method 29 (portion for mercury only);
     IBR of an alternative test method for EPA Method 624;
     Use of an alternative test method for EPA Method 3B (for
the manual procedures only and not the instrumental procedures);
     Use of an alternative test method for EPA Method 320 (with
caveats); and
     Several minor editorial and technical changes in the
subpart.

III. What is included in this final rule?

    This action provides the EPA's final determinations pursuant to the
RTR provisions of CAA section 112 for the Miscellaneous Organic
Chemical Manufacturing source category and amends the MON based on
those determinations. This action also finalizes other changes to the
NESHAP, including adding requirements and clarifications for periods of
SSM and bypasses; revising the operating and monitoring requirements
for flares that control ethylene oxide emissions, flares used to
control emissions from processes that produce olefins and polyolefins
and allowing flares outside of this subset to comply with these amended
flare requirements; adding provisions for electronic reporting of
performance test results and reports, performance evaluation reports,
and compliance reports; and other minor editorial and technical
changes. This action also reflects several changes to the December 17,
2019, RTR proposal (84 FR 69182), in consideration of comments received
during the public comment period as described in section IV of this
preamble.

A. What are the final rule amendments based on the risk review for the
Miscellaneous Organic Chemical Manufacturing source category?

    This section describes the final amendments to the MON being
promulgated pursuant to CAA section 112(f). Consistent with the
proposal, the EPA determined that the risks for this source category
under the current MACT provisions are unacceptable. When risks are
unacceptable, the EPA must determine the emissions standards necessary
to reduce risk to an acceptable level. As such, the EPA is promulgating
final amendments to the MON pursuant to CAA section 112(f)(2) that
require control of ethylene oxide for process vents, storage tanks, and
equipment in ethylene oxide service, with some changes in the final
rule due to comments received during the public comment period. As
discussed in section IV.A of this preamble, implementation of these
controls will reduce risk to an acceptable level that also provides an
ample margin of safety to protect public health. For process vents in
ethylene oxide service, the EPA is finalizing the requirement, as
proposed, to either reduce emissions of ethylene oxide by (1) venting
emissions through a closed-vent system to a control device that reduces
ethylene oxide by greater than or equal to 99.9 percent by weight, to a
concentration less than 1 ppmv for each process vent, or to less than 5
lb/yr for all combined process vents; or (2) venting emissions through
a closed-vent system to a flare meeting the flare operating
requirements discussed in sections IV.A.1 and IV.C.2 of the proposal
preamble (84 FR 69182, December 17, 2019). However, based on comments
received on the proposed rulemaking, we are revising the proposed
definition of ``in ethylene oxide service'' for process vents by
removing ``undiluted'' from the mass-based criteria and removing the
phrase ``anywhere in the process.'' In the final rule, a process vent
in ethylene oxide service means each batch and continuous process vent
in a process that, when uncontrolled, contains a concentration of
greater than or equal to 1 ppmv undiluted ethylene oxide, and when
combined, the sum of all these process vents would emit uncontrolled,
ethylene oxide emissions greater than or equal to 5 lb/yr [2.27
kilograms per year (kg/yr)]. In addition, based on comments received on
the proposed rulemaking, we are revising the definitions of ``batch
process vent'' and ``continuous process vent'' in the final rule to
clarify that: (1) The existing 50 ppmv HAP and 200 lb/yr uncontrolled
HAP emission cut-offs do not apply to batch process vents in ethylene
oxide service; and (2) the existing 0.005 weight percent total organic
HAP cut-off in 40 CFR 63.107(d) does not apply to continuous process
vents in ethylene oxide service.

    For storage tanks in ethylene oxide service, we are finalizing a
requirement, as proposed, to reduce emissions of ethylene oxide by
either (1) venting emissions through a closed-vent system to a control
device that reduces ethylene oxide by greater than or equal to 99.9
percent by weight or to a concentration less than 1 ppmv for each
storage tank vent; or (2) venting emissions through a closed-vent
system to a flare meeting the flare operating requirements discussed in
sections IV.A.1 and IV.C.2 of the proposal preamble (84 FR 69182,
December 17, 2019). However, based on comments received on the proposed
rulemaking, we are revising the proposed definition of ``in ethylene
oxide service'' for storage tanks by revising the concentration of
ethylene oxide criteria to a 0.1 percent by weight threshold. In the
final rule, a storage tank in ethylene oxide service means a storage
tank of any capacity and vapor pressure storing a liquid that is at
least 0.1 percent by weight of ethylene oxide. We are also finalizing,
as proposed, that the exemptions for ``vessels storing organic liquids
that contain HAP only as impurities'' and ``pressure vessels designed
to operate in excess of 204.9 kilopascals and without emissions to the
atmosphere'' listed in the definition of ``storage tank'' at 40 CFR
63.2550(i) do not apply for storage tanks in ethylene oxide service.
    Additionally, for both process vents in ethylene oxide service and
storage tanks in ethylene oxide service, we are removing the option to
allow use of a design evaluation in lieu of performance testing to
demonstrate compliance to ensure that the required level of control is
achieved, consistent with the proposal. We are also finalizing, as
proposed, that after promulgation of the rule, owners or operators that
choose to control emissions with a non-flare control device conduct an
initial performance test according to 40 CFR 63.997 and 40 CFR
63.2450(g) on each existing control device in ethylene oxide service
and on each newly installed control device in ethylene oxide service to
verify performance at the required level of control. Subsequently, we
are finalizing that owners or operators conduct periodic performance
testing on non-flare control devices in ethylene oxide service every 5
years. We are also finalizing the proposed requirement for continuous
monitoring of operating parameters for scrubbers used to control
emissions from process vents in ethylene oxide service or storage tanks
in ethylene oxide service, to ensure that the factors needed for the
reaction to occur are met (i.e., liquid-to-gas ratio, pressure drop
across the scrubber, liquid feed pressure, liquid temperature, and pH),
although we are revising the requirement to set the pressure drop
across the scrubber and the liquid feed pressure based on the
performance test, and instead, we are allowing the limits on these
parameters to be based on the manufacturer's recommendations or
engineering analysis. Additionally, we are changing the continuous
compliance requirements for the operating parameters, such that
compliance with the operating parameter limits is determined on an
hourly average basis instead of an instantaneous basis.
    For equipment leaks, the EPA is promulgating final amendments for
co-proposed equipment leak ``Control Option 1'' for controlling
emissions from MON equipment in ethylene oxide service, except based on
comments received on the proposed rulemaking, in lieu of prohibiting
PRDs in ethylene oxide service from releasing directly to the
atmosphere, we are clarifying in the final rule that these PRDs must
comply with the pressure release management work practice standards
proposed at 40 CFR 63.2480(e) and (f). We are also clarifying that any
release event from PRDs in ethylene oxide service is a deviation of the
standard. The EPA is not finalizing co-proposed equipment leak
``Control Option 2.'' As proposed under equipment leak Control Option
1, we are promulgating the following requirements:
     All light liquid pumps in ethylene oxide service be
monitored monthly at a leak definition of 1,000 ppm, and when a leak is
detected, it be repaired as soon as practicable, but not later than 15
calendar days after it is detected;
     the leak repair exemption available for pumps at 40 CFR
63.1026(b)(3), 40 CFR 63.163(c)(3), and 40 CFR 65.107(b)(3) does not
apply to equipment in ethylene oxide service; and
     all gas/vapor and light liquid connectors in ethylene
oxide service are required to be monitored annually at a leak
definition of 500 ppm, and when a leak is detected, be repaired as soon
as practicable, but not later than 15 calendar days after it is
detected.
    Refer to section IV.C.2 of the proposal preamble (84 FR 69182,
December 17, 2019) for further discussion of co-proposed Control Option
1.
    Section IV.A.3 of this preamble provides a summary of key comments
we received regarding the risk review and our responses.

B. What are the final rule amendments based on the technology review
for the Miscellaneous Organic Chemical Manufacturing source category?

    For process vents, storage tanks, transfer racks, and wastewater
streams in this source category, the EPA is finalizing its proposed
determination in the technology review that there are no developments
in practices, processes, and control technologies that warrant
revisions to the MACT standards. Therefore, we are not finalizing
revisions to the MACT standards for these emission sources under CAA
section 112(d)(6).
    For leaks from equipment not in ethylene oxide service, we
determined that there are developments in practices, processes, and
control technologies that warrant revisions to the MACT standards for
this source category. Therefore, to satisfy the requirements of CAA
section 112(d)(6), we are revising the MACT standards, consistent with
the proposed rule (84 FR 69182, December 17, 2019), to lower the leak
definition for pumps in light liquid service (in an MCPU that has no
continuous process vents and is part of an existing source) from 10,000
ppmv to 1,000 ppmv with monthly monitoring to comply with the
requirements in 40 CFR part 63, subpart H or UU, or 40 CFR part 65,
subpart F, and to require initial monitoring for equipment leaks within
30 days after initial startup of new or replaced equipment. However,
based on comments received on the proposed rulemaking, we are
clarifying in the final rule that the initial monitoring of equipment
is only required if the new or replaced equipment is subject to Table 6
to 40 CFR part 63, subpart FFFF, and is also subject to periodic
monitoring with EPA Method 21 of appendix A-7 to 40 CFR part 60; and
that the initial monitoring does not apply to equipment classified as
unsafe-to-monitor or difficult-to-monitor equipment.
    For heat exchange systems, we determined that there are
developments in practices, processes, and control technologies that
warrant revisions to the MACT standards for this source category.
Therefore, to satisfy the requirements of CAA section 112(d)(6), we are
revising the MACT standards, consistent with the proposed rule (84 FR
69182, December 17, 2019), to include revisions to the heat exchange
system requirements to require owners or operators to use the Modified
El Paso Method and repair leaks of total strippable hydrocarbon
concentration (as methane) in the stripping gas of 6.2 ppmv or greater.
However, based on

comments received on the proposed rulemaking, we are also making some
technical clarifications to allow compliance with the Modified El Paso
Method using an alternative mass-based leak action level of total
strippable hydrocarbon equal to or greater than 0.18 kilograms per hour
(instead of the proposed concentration-based leak action level) for
small heat exchange systems with a recirculation rate of 10,000 gallons
per minute (gpm) or less. We are also finalizing the proposed
specification that none of the heat exchange system requirements apply
to heat exchange systems that have a maximum cooling water flow rate of
10 gpm or less.
    Section IV.B.3 of this preamble provides a summary of key comments
we received on the technology review and our responses.

C. What are the final rule amendments pursuant to CAA section 112(d)(2)
and (3) and 112(h) for the Miscellaneous Organic Chemical Manufacturing
source category?

    Consistent with Sierra Club v. EPA 551 F. 3d 1019 (D.C. Cir. 2008)
and the December 17, 2019, RTR proposal (84 FR 69182), we are revising
monitoring and operational requirements for flares that control
ethylene oxide emissions and flares used to control emissions from
processes that produce olefins and polyolefins (with the option for an
owner or operator of a flare outside of this subset to choose to opt in
to the proposed requirements in lieu of complying with the current
flare standards) to ensure these flares meet the MACT standards at all
times when controlling HAP emissions. However, based on comments
received on the proposed rulemaking, we are not finalizing the work
practice standard for velocity exceedances for flares operating above
their smokeless capacity. We are also clarifying in the final rule that
a ``flare that controls ethylene oxide emissions'' is a flare that
controls ethylene oxide emissions from affected sources in ethylene
oxide service as defined in 40 CFR 63.2550. In addition, we are
clarifying in the final rule that ``an MCPU that produces olefins or
polyolefins'' includes only those MCPUs that manufacture ethylene,
propylene, polyethylene, and/or polypropylene as a product; conversely,
by-products and impurities as defined in 40 CFR 63.101, as well as
wastes and trace contaminants, are not considered products.
    In addition, we are finalizing provisions and clarifications as
proposed for periods of SSM and bypasses, including PRD releases;
bypass lines on closed vent systems; maintenance activities; and
certain gaseous streams routed to a fuel gas system to ensure that CAA
section 112 standards apply continuously.
    Lastly, based on comments received on the proposed rulemaking, we
are finalizing a separate standard for storage vessel degassing for
storage vessels subject to the control requirements in Table 4 to 40
CFR part 63, subpart FFFF.
    Section IV.C.3 of this preamble provides a summary of key comments
we received on the CAA section 112(d)(2) and (3) provisions and our
responses.

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

    We are finalizing the proposed amendments to the MON to remove and
revise provisions related to SSM. In its 2008 decision in Sierra Club
v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), the Court vacated portions of
two provisions in the EPA's CAA section 112 regulations governing the
emissions of HAP during periods of SSM. Specifically, the Court vacated
the SSM exemptions contained in 40 CFR 63.6(f)(1) and (h)(1), holding
that under section 302(k) of the CAA, emissions standards or
limitations must be continuous in nature and that the SSM exemptions
violate the CAA's requirement that some CAA section 112 standards apply
at all times. As detailed in section IV.E.1 of the proposal preamble
(see 84 FR 69182, December 17, 2019), the MON requires that the
standards apply at all times (see 40 CFR 63.2450(a)(2)), consistent
with the Court decision in Sierra Club v. EPA, 551 F. 3d 1019 (D.C.
Cir. 2008). We determined that facilities in this source category can
meet the applicable MACT standards at all times, including periods of
startup and shutdown. As discussed in the proposal preamble, the EPA
interprets CAA section 112 as not requiring emissions that occur during
periods of malfunction to be factored into development of CAA section
112 standards, although the EPA has the discretion to set standards for
malfunction periods where feasible. Where appropriate, and as discussed
in section III.C of this preamble, we are also finalizing alternative
standards for certain emission points during periods of SSM to ensure a
CAA section 112 standard applies ``at all times.'' Other than for those
specific emission points discussed in section III.C of this preamble,
the EPA determined that no additional standards are needed to address
emissions during periods of SSM. We determined that facilities in this
source category can meet the applicable MACT standards at all times,
including periods of startup and shutdown.
    We are finalizing revisions to the General Provisions table (Table
12 to 40 CFR part 63, subpart FFFF) to eliminate requirements that
include rule language providing an exemption for periods of SSM.
Additionally, we are finalizing our proposal to eliminate language
related to SSM that treats periods of startup and shutdown the same as
periods of malfunction. Finally, we are finalizing our proposal to
revise reporting and recordkeeping requirements for deviations as they
relate to exemptions for periods of SSM. As discussed in section IV.E.1
of the proposal preamble, these revisions are consistent with the
requirement in 40 CFR 63.2450(a)(2) that the standards apply at all
times. We are also finalizing, as proposed, a revision to the
performance testing requirements. The final performance testing
provisions prohibit performance testing during SSM because these
conditions are not representative of normal operating conditions. The
final rule also requires, as proposed, that operators maintain records
to document that operating conditions during the test represent normal
operations.
    The legal rationale and detailed revisions for SSM periods that we
are finalizing here are set forth in the proposal preamble (84 FR
69224-69227, December 17, 2019). Also, based on comments received
during the public comment period, we are revising specific references
listed in 40 CFR 63.2450(e)(4), 40 CFR 63.2480(f), and 40 CFR
63.2485(p) and (q) to sufficiently address the SSM exemption provisions
from subparts referenced by the MON (e.g., the MON references 40 CFR
part 63, subparts F, G, SS, UU, WW, and GGG; and each of these
referenced subparts have SSM provisions that we are removing in 40 CFR
63.2450(e)(4), 40 CFR 63.2480(f), and 40 CFR 63.2485(p) and (q) for
owners or operators that must comply with the MON). In other words, in
addition to what we proposed, we are also clarifying that the certain
referenced provisions do not apply when demonstrating compliance with
the MACT standards, such as phrases like ``other than a start-up,
shutdown, or malfunction'' in the recordkeeping and reporting
requirements of 40 CFR part 63, subparts SS and UU. We are also not
removing as proposed the term ``breakdowns'' in 40 CFR 63.998(b)(2)(i)
as we determined based on a public comment that removing the term is
unnecessary and could result in inaccurate calculation of parameter
values. Finally, we are also not

removing 40 CFR 63.998(d)(1)(ii) in its entirety as proposed because we
determined based on a public comment received that these records are
used to demonstrate compliance with the bypass provisions and do not
apply to SSM. As discussed in section III.C of this preamble, we are
also finalizing alternative standards for certain emission points
(i.e., emergency flaring, PRDs, maintenance activities, and tank
degassing) during periods of SSM to ensure a CAA section 112 standard
applies ``at all times.''
    Section IV.D.3 of this preamble provides a summary of key comments
we received on the SSM provisions and our responses.

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

    This rule also finalizes, as proposed, revisions to several other
NESHAP requirements. We describe these revisions in this section as
well as other proposed provisions that have changed since proposal.
1. Electronic Reporting
    To increase the ease and efficiency of data submittal and data
accessibility, we are finalizing, as proposed, a requirement that
owners or operators of MON facilities submit electronic copies of
certain required flare management plans (being finalized at 40 CFR
63.2450(e)(5)(iv)), compliance reports (being finalized at 40 CFR
63.2520(e)), performance test reports (being finalized at 40 CFR
63.2520(f)), and performance evaluation reports (being finalized at 40
CFR 63.2520(g)) through the EPA's Central Data Exchange (CDX) using the
Compliance and Emissions Data Reporting Interface (CEDRI). The final
rule requires that performance test results collected using test
methods that are supported by the EPA's Electronic Reporting Tool (ERT)
as listed on the ERT website \3\ at the time of the test be submitted
in the format generated through the use of the ERT and that other
performance test results be submitted in portable document format (PDF)
using the attachment module of the ERT. Similarly, performance
evaluation results of continuous emissions monitoring systems (CEMS)
measuring relative accuracy test audit pollutants that are supported by
the ERT at the time of the test must be submitted in the format
generated through the use of the ERT and other performance evaluation
results be submitted in PDF using the attachment module of the ERT. For
compliance reports, the final rule requires that owners or operators
use the appropriate spreadsheet template to submit information to
CEDRI. The final version of the template for these reports will be
located on the CEDRI website.\4\ The final rule requires that flare
management plans be submitted as a PDF upload in CEDRI. In addition, in
the final rule, we are correcting an error to clarify that compliance
reports must be submitted electronically (i.e., through the EPA's CDX
using the appropriate electronic report template for this subpart)
beginning August 12, 2023, or once the reporting template has been
available on the CEDRI website for 1 year, whichever date is later.
Furthermore, we are finalizing, as proposed, provisions that allow
facility operators the ability to seek extensions for submitting
electronic reports for circumstances beyond the control of the
facility, i.e., for a possible outage in the CDX or CEDRI or for a
force majeure event in the time just prior to a report's due date, as
well as the process to assert such a claim.
---------------------------------------------------------------------------

    \3\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
    \4\ https://www.epa.gov/electronic-reporting-air-emissions/cedri.
---------------------------------------------------------------------------

    For a more detailed discussion of these final amendments to the
MON, see section IV.E.2.b of the proposal preamble (84 FR 69227,
December 17, 2019), as well as section VI.C below on compliance with
the Paperwork Reduction Act. For a more thorough discussion of
electronic reporting, see the memorandum, Electronic Reporting
Requirements for New Source Performance Standards (NSPS) and National
Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, which
is available in the docket for this rulemaking (see Docket Item No.
EPA-HQ-OAR-2018-0746-0169).
2. Monitoring for Adsorbers That Cannot Be Regenerated and Regenerative
Adsorbers That Are Regenerated Offsite
    We are finalizing requirements at 40 CFR 63.2450(e)(7), as
proposed, for owners or operators using adsorbers that cannot be
regenerated and regenerative adsorbers that are regenerated offsite to
use dual (two or more) adsorbent beds in series and conduct monitoring
of HAP or total organic compound (TOC) on the outlet of the first
adsorber bed in series using a sample port and a portable analyzer or
chromatographic analysis. However, we are revising the proposed rule
text in this final action to reduce the monitoring frequency in
response to public comments. In the final rule, owners or operators
will establish the estimated bed life from a design evaluation of the
adsorber. The monitoring frequency increases as the remaining bed life
decreases. Owners or operators will monitor monthly when remaining bed
life is more than 2 months, weekly when remaining bed life is between 2
months and 2 weeks, and daily when remaining bed life is less than 2
weeks.
3. Exemptions for Heat Exchange Systems
    To correct a disconnect between having a National Pollutant
Discharge Elimination System (NPDES) permit that meets certain
allowable discharge limits at the discharge point of a facility (e.g.,
outfall) and being able to adequately identify a leak, we are
finalizing, as proposed, the removal of certain exemptions for once-
through heat exchange systems to comply with cooling water monitoring
requirements.\5\ However, as discussed further in the response to
comment document for this rulemaking, we are adding back in exemptions
originating from 40 CFR 63.104(a)(1), (2), (5), and (6) that were
inadvertently removed in the proposed rule.
---------------------------------------------------------------------------

    \5\ Cooling water from a once-through heat exchange system at a
petrochemical plant can be mixed with other sources of water (e.g.,
cooling water used in once-through heat exchange systems in other
source categories, stormwater, treated wastewater, etc.) in sewers,
trenches, and ponds prior to discharge from the plant. If this point
of discharge from the plant is into a ``water of the United
States,'' then the facility is required to have a NPDES permit and
to meet certain pollutant discharge limits.
---------------------------------------------------------------------------

4. Minor Clarifications and Corrections
    We are finalizing all of the revisions that we proposed for
clarifying text or correcting typographical errors, grammatical errors,
and cross-reference errors. These editorial corrections and
clarifications are summarized in Table 11 of the proposal preamble. See
84 FR 69228, December 17, 2019. We are also including several
additional minor clarifying edits in the final rule based on comments
received during the public comment period. We did not receive many
substantive comments on these other amendments in the Miscellaneous
Organic Chemical Manufacturing RTR proposal. The comments and our
specific responses to these items can be found in the document, Summary
of Public Comments and Responses for the Risk and Technology Review for
Miscellaneous Organic Chemical Manufacturing, available in the docket
for this rulemaking.

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

    The revisions to the MACT standards being promulgated in this
action are effective on August 12, 2020. New affected sources that
commenced construction or reconstruction after December 17, 2019 must
comply with all of the standards immediately upon the effective date of
the standard, or upon startup, whichever is later.
    Existing sources and new affected sources that commenced
construction or reconstruction after April 4, 2002, and on or before
December 17, 2019, must comply with the amended standards according to
the following compliance schedules, with two exceptions: (1) We are
revising the General Provisions applicability table (Table 12 to 40 CFR
part 63, subpart FFFF) to clarify that for all affected sources, the
SSM exemptions contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1) do
not apply given the Court vacatur in Sierra Club v. EPA, 551 F. 3d 1019
(D.C. Cir. 2008); and (2) electronic reporting of performance test
reports and performance evaluations are required, as proposed, upon
startup or no later than 60 days after the effective date of the final
rule, whichever is later.
     Upon initial startup or on August 12, 2023, whichever is
later, for the following amendments: (1) The amendments specified in 40
CFR 63.2445(g), which include all amendments finalized under CAA
sections 112(d)(2) and (3) and the heat exchange systems amendments
finalized under CAA section 112(d)(6); (2) the amendments related to
SSM at 40 CFR 63.2420(e)(4) and 63.2525(j); and (3) the amendments
related to electronic reporting of flare management plans at 40 CFR
63.2450(e)(5)(iii) and compliance reports.
     Upon initial startup or on August 12, 2021, whichever is
later, for the amendments specified in 40 CFR 63.2445(h), which include
the amendments finalized under CAA section 112(d)(6) for equipment
leaks (i.e., pumps in light liquid service in an MCPU that has no
continuous process vents and is part of an existing source).
     Upon initial startup or on August 12, 2022, whichever is
later, for the amendments specified in 40 CFR 63.2445(i), which include
amendments finalized under CAA section 112(f) for process vents,
storage tanks, and equipment that are in ethylene oxide service.
    Except for the compliance schedule for the SSM exemptions contained
in 40 CFR 63.6(f)(1) and (h)(1) as previously described in this section
of the preamble, these compliance schedules have not changed from
proposal. However, we are correcting a typographical error to include
the word ``on'' in the phrase ``upon initial startup or on'' of each
schedule. We provide a summary in this section of our rationale for the
compliance schedule being finalized for existing sources and new
affected sources that commenced construction or reconstruction after
April 4, 2002, and on or before December 17, 2019. Refer to section
IV.F of the proposal preamble (84 FR 69182, December 17, 2019) for
additional detail regarding our rationale for the compliance schedules
being finalized, with the exception of the compliance schedule for the
amendments finalized under CAA section 112(d)(6) for equipment leaks,
which is discussed below. We received comments both in support of and
in opposition to the proposed compliance schedules. Most commenters
generally supported the proposed compliance schedules and said that
owners or operators would need a significant period of time to comply
with the proposed revisions. Only one commenter objected to the
proposed compliance schedules, and primarily argued against the
proposed 2-year compliance delay for the amendments made under CAA
section 112(f) (for process vents, storage tanks, and equipment that
are in ethylene oxide service). Summaries of these comments and the
EPA's responses can be found in the document, Summary of Public
Comments and Responses for the Risk and Technology Review for
Miscellaneous Organic Chemical Manufacturing, available in the docket
for this rulemaking.
    CAA section 112(i) provides that the compliance date shall be as
expeditious as practicable, but no later than 3 years after the
effective date of the standard. In determining what compliance period
is as expeditious as practicable, we consider the amount of time needed
to plan and construct projects and change operating procedures. For all
amendments being finalized under CAA sections 112(d)(2) and (3), the
heat exchange systems amendments being finalized under CAA section
112(d)(6), the amendments related to SSM (except for the SSM exemptions
contained in 40 CFR 63.6(f)(1) and (h)(1) as previously described in
this section of the preamble), and electronic reporting of flare
management plans and compliance reports, we determined that sources
will require up to 3 years after August 12, 2020 to comply with the
requirements for the following reasons:
     The operating and monitoring requirements for flares being
finalized under CAA sections 112(d)(2) and (3) will require the
installation of new flare monitoring equipment and likely a new control
system to monitor and adjust assist gas addition rates, which will
require the flare to be taken out of service and may require a
significant portion of the MCPU to be shutdown.
     The work practice standards for atmospheric PRDs in
organic HAP service being finalized under CAA sections 112(d)(2) and
(3) will necessitate sources to identify the most appropriate
preventive measures or control approach; design, install, and test the
system; install necessary process instrumentation and safety systems;
and may need to time installations with equipment shutdown or
maintenance outages.
     The vent control requirements for bypasses being finalized
under CAA sections 112(d)(2) and (3) will require the addition of
piping and potentially new controls, which will likely be routed to the
flare, such that these bypass modifications will need to be coordinated
with the installation of the new monitoring equipment for the flares.
     The heat exchange system amendments being finalized under
CAA section 112(d)(6) will require engineering evaluations,
solicitation and review of vendor quotes, contracting and installation
of monitoring equipment, operator training, and updating standard
operating procedures.
     The removal of the exemptions from the requirements to
meet the standard during SSM periods and the addition of electronic
reporting will necessitate reading and understanding these new
requirements, evaluation of operations to ensure that they can meet the
standards during periods of startup and shutdown, making necessary
adjustments to standard operating procedures, and converting reporting
mechanisms to install necessary hardware and software. In sum,
considering the timeframe needed to come into compliance with all of
the removed exemptions in this final rule (which in certain cases, will
require installation of complex equipment and system changes for
flares), the EPA considers a period of 3 years after the effective date
of the final rule to be the most expeditious compliance period
practicable.
    For the equipment leak amendments being finalized under CAA section
112(d)(6), for pumps in light liquid service (in an MCPU that has no
continuous process vents and is part of an existing source), we
determined that sources will require up to 1 year after August 12, 2020
because, while the

change to lower the leak definition can be implemented relatively
quickly as it requires no additional equipment, it will still require
changes to a facilities monitoring program and coordination in
monitoring schedules, changes to recordkeeping activities and
electronic databases, and changes to reporting forms.
    For all amendments being finalized under CAA section 112(f) for
process vents in ethylene oxide service, storage tanks in ethylene
oxide service, and equipment in ethylene oxide service, we determined
that sources will require up to 2 years after August 12, 2020 to comply
with the requirements to allow time to plan, purchase, and install
equipment for ethylene oxide control. For example, for process vents,
if the affected source cannot demonstrate 99.9-percent control of
ethylene oxide emissions or reduce ethylene oxide emissions to less
than 1 ppmv (from each process vent) or 5 lb/yr (for all combined
process vents), then a new control system will need to be installed.
Sufficient time will be needed to properly engineer the project, obtain
capital authorization and funding, procure the equipment, construct and
start-up the equipment, prepare for the initial performance test, set
up new software, and develop operating procedures.

IV. What is the rationale for our final decisions and amendments for
the Miscellaneous Organic Chemical Manufacturing source category?

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

A. Residual Risk Review for the Miscellaneous Organic Chemical
Manufacturing Source Category

1. What did we propose pursuant to CAA section 112(f) for the
Miscellaneous Organic Chemical Manufacturing source category?
    Pursuant to CAA section 112(f), the EPA conducted a residual risk
review and presented the results of this review, along with our
proposed decisions regarding risk acceptability and ample margin of
safety, in the December 17, 2019, proposed rule for 40 CFR part 63,
subpart FFFF (84 FR 69182). The results of the risk assessment for the
proposal are presented briefly in Table 2 of this preamble. More detail
is in the residual risk technical support document, Residual Risk
Assessment for the Miscellaneous Organic Chemical Manufacturing Source
Category in Support of the 2019 Risk and Technology Review Proposed
Rule, which is available in the docket for this rulemaking (see Docket
Item No. EPA-HQ-OAR-2018-0746-0011).

                        Table 2--Miscellaneous Organic Chemical Manufacturing Source Category Risk Assessment Results in Proposal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Maximum         Estimated population at        Estimated
                                         individual     increased risk of cancer \2\    annual cancer      Maximum
      Number of  facilities \1\          cancer risk  --------------------------------    incidence        chronic     Maximum screening acute noncancer
                                       (in 1 million)     >100-in-1       >=1-in-1       (cases per       noncancer                    HQ
                                             \2\           million         million        year) \2\       TOSHI \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
194..................................           2,000          18,000       2,900,000             0.4               1  HQREL = 6 (acrolein).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\3\ Actual emissions equal allowable emissions; therefore, actual risks equal allowable risks.

    The results of the proposed chronic baseline inhalation cancer risk
assessment at proposal indicated that, based on estimates of current
actual and allowable emissions, the MIR posed by the source category
was 2,000-in-1 million driven by ethylene oxide emissions from storage
tanks (75 percent), equipment leaks (15 percent), and process vents (8
percent). At proposal, the total estimated cancer incidence from this
source category was estimated to be 0.4 excess cancer cases per year,
or one case in every 2.5 years. Approximately 2.9 million people were
estimated to have cancer risks above 1-in-1 million from HAP emitted
from the facilities in this source category. At proposal, the estimated
maximum chronic noncancer target organ-specific hazard index (TOSHI)
for the source category was 1, indicating low likelihood of adverse
noncancer effects from long-term inhalation exposures.
    As shown in Table 2 of this preamble, the worst-case acute hazard
quotient (HQ) (based on the reference exposure level (REL)) at proposal
was 6 based on the REL for acrolein (the next highest dose-response
value for acrolein, the acute exposure guideline level-1 (AEGL-1),
results in an HQ of 0.2). There were 11 additional instances of acute
HQs greater than 1 from the source category. In addition, at proposal,
the multipathway risk screening assessment resulted in a maximum Tier 2
cancer screening value (SV) of 10 for polycyclic organic matter (POM)
for the farmer scenario. The Tier 2 SVs for all other HAP known to be
persistent and bio-accumulative in the environment (PB-HAP) emitted
from the source category (mercury compounds, cadmium compounds, and
arsenic compounds) were less than 1. The Tier 2 cancer SV for POM means
that the maximum cancer risk from exposure to POM emissions through
ingestion of farm products is less than 10-in-1 million. At proposal,
no site-specific assessment using TRIM.FaTE (which incorporates AERMOD
deposition, enhanced soil/water run-off calculations, and model
boundary identification) or Tier 3 screening assessment was deemed
necessary due to the conservative nature of the Tier 2 screen and the
hypothetical construct of the farmer scenario. Also, at proposal, the
highest annual average lead concentration of 0.0006 micrograms per
cubic meter was well below the National Ambient Air Quality Standards
for lead, indicating low potential for multipathway risk of concern due
to lead emissions.
    At proposal, the maximum lifetime individual cancer risk posed by
the 194 modeled facilities, based on whole facility emissions, was
3,000-in-1 million, with ethylene oxide emissions from fugitive
emissions and flares from the Synthetic Organic Chemical

Manufacturing, Polyether Polyols Production, and Miscellaneous Organic
Chemical Manufacturing source categories driving the risk. Regarding
the noncancer risk assessment, the maximum chronic noncancer hazard
index (HI) posed by whole facility emissions was estimated to be 7 (for
the respiratory system as the target organ), driven by emissions of
chlorine and methyl bromide from non-source category sources identified
as brominated organic manufacturing.
    We weighed all health risk factors, including those shown in Table
2 of this preamble, in our risk acceptability determination and
proposed that the risks posed by this source category under the current
MACT provisions are unacceptable (section IV.C of the proposal
preamble, 84 FR 69182, December 17, 2019). At proposal, we identified
ethylene oxide as the driver of the unacceptable risk and evaluated
several options to control ethylene oxide emissions from (1) process
vents, (2) storage tanks, and (3) equipment ``in ethylene oxide
service.'' For process vents, we proposed to define ``in ethylene oxide
service'' to mean that each batch and continuous process vent in a
process that, when uncontrolled, contains a concentration of greater
than or equal to 1 ppmv undiluted ethylene oxide, and when combined,
the sum of all these process vents would emit uncontrolled, undiluted
ethylene oxide emissions greater than or equal to 5 lb/yr (2.27 kg/yr).
For storage tanks of any capacity and vapor pressure, we proposed to
define ``in ethylene oxide service'' to mean that the concentration of
ethylene oxide of the stored liquid is greater than or equal to 1 ppmw.
We proposed that the exemptions for ``vessels storing organic liquids
that contain HAP only as impurities'' and ``pressure vessels designed
to operate in excess of 204.9 kilopascals and without emissions to the
atmosphere'' listed in the definition of ``storage tank'' at 40 CFR
63.2550(i) do not apply for storage tanks in ethylene oxide service.
For the ethylene oxide equipment leak provisions, we proposed to define
``in ethylene oxide service'' to mean any equipment that contains or
contacts a fluid (liquid or gas) that is at least 0.1 percent by weight
of ethylene oxide.
    To reduce risks from process vents in ethylene oxide service, we
proposed requirements at 40 CFR 63.2493 to reduce emissions of ethylene
oxide by either (1) venting emissions through a closed-vent system to a
control device that reduces ethylene oxide by greater than or equal to
99.9 percent by weight, to a concentration less than 1 ppmv for each
process vent, or to less than 5 lb/yr for all combined process vents;
or (2) venting emissions through a closed-vent system to a flare
meeting the flare operating requirements discussed in section IV.A.1 of
the proposal preamble (84 FR 69182, December 17, 2019).
    To reduce risks from storage tanks in ethylene oxide service, we
proposed a requirement at 40 CFR 63.2493 to reduce emissions of
ethylene oxide by either (1) venting emissions through a closed-vent
system to a control device that reduces ethylene oxide by greater than
or equal to 99.9 percent by weight or to a concentration less than 1
ppmv for each storage tank vent; or (2) venting emissions through a
closed-vent system to a flare meeting the flare operating requirements
discussed in section IV.A.1 of the proposal preamble (84 FR 69182,
December 17, 2019).
    To reduce risks from equipment leaks in ethylene oxide service, we
co-proposed two control options at 40 CFR 63.2493 (see Table 6 of the
proposal preamble, 84 FR 69182, December 17, 2019). In equipment leak
co-proposed Control Option 1, we proposed that all light liquid pumps
in ethylene oxide service be monitored monthly at a leak definition of
1,000 ppm, and when a leak is detected, it be repaired as soon as
practicable, but not later than 15 calendar days after it is detected.
Additionally, under co-proposed Control Option 1, we proposed that the
leak repair exemption available for pumps at 40 CFR 63.1026(b)(3), 40
CFR 63.163(c)(3), and 40 CFR 65.107(b)(3) would not apply to equipment
in ethylene oxide service. Also, as part of co-proposed Control Option
1, we proposed that all gas/vapor and light liquid connectors in
ethylene oxide service be monitored annually at a leak definition of
500 ppm, and when a leak is detected, it be repaired as soon as
practicable, but not later than 15 calendar days after it is detected.
In equipment leak co-proposed Control Option 2, we proposed that more
stringent equipment leak standards would apply to two facilities with a
MIR greater than 100-in-1 million (i.e., Lanxess Corporation and
Huntsman Performance). For these two facilities, at proposal, light
liquid pumps in ethylene oxide service would be required to be leakless
(i.e., have zero emissions) and monitored annually to verify there are
no emissions; and gas and light liquid valves in ethylene oxide service
would be required to either be leakless and monitored annually or not
be leakless and be monitored quarterly. For these two facilities, at
proposal, light liquid pumps and gas and light liquid valves in
ethylene oxide service would be considered leaking if an instrument
reading above background is found; and connectors in ethylene oxide
service would be monitored monthly at a leak definition of 100 ppm. We
proposed that when a leak is detected, it be repaired as soon as
practicable, but not later than 15 calendar days after it is detected,
and a first attempt at repair be made no later than 5 calendar days
after the leak is detected. As part of co-proposed Control Option 2, we
proposed all other facilities with MON equipment in ethylene oxide
service would be subject to the standards previously described in
equipment leak co-proposed Control Option 1.
    After implementation of the proposed controls for process vents and
storage tanks at MON facilities emitting ethylene oxide, as well as
implementation of either of the co-proposed control options for
equipment leaks, we proposed that the resulting risks would be
acceptable for this source category. We also acknowledged at proposal
that estimated post-control risks would be greater than 100-in-1
million (i.e., 200- to 300-in-1 million) and determined that, due to
the inherent health protective nature of our risk assessment methods
and certain uncertainties,\6\ the proposed risk assessment is more
likely to overestimate rather than underestimate the risks (see section
IV.C.3 of the proposal preamble, 84 FR 69182, December 17, 2019). In
our proposal, we presented the risk impacts using health risk measures
and information, including the MIR, cancer incidence, population
exposed to cancer risks greater than 100-in-1 million, and associated
uncertainty in emissions estimates after incremental application of the
proposed options to control ethylene oxide emissions from (1) process
vents, (2) storage tanks, and (3) equipment in ethylene oxide service
(see Table 7 of the proposal preamble, 84 FR 69182, December 17, 2019).
At proposal, we determined application of the ethylene oxide-specific
controls for process vents and storage tanks would reduce ethylene
oxide emissions by an estimated 89 percent for the source category, and
the estimated MIR would be reduced from 2,000-in-1 million to 400-in-1
million at Lanxess Corporation, and the next highest estimated MIR
would be 300-in-1 million at Huntsman Performance. In both cases, we
determined that the remaining risk

would be primarily from equipment leak emissions of ethylene oxide.
Subsequent application of equipment leak co-proposed Control Option 1
would further reduce ethylene oxide emissions by 4 percent, for a total
estimated 93-percent reduction in ethylene oxide emissions for the
source category, with the MIR at Lanxess Corporation being further
reduced to 200-in-1 million and the MIR at Huntsman Performance
remaining at 300-in-1 million. Alternatively, subsequent application of
equipment leak co-proposed Control Option 2 (instead of Control Option
1) would reduce ethylene oxide emissions by a total estimated 94-
percent for the source category, with the MIR at Lanxess Corporation
being further reduced to 100-in-1 million and the MIR at Huntsman
Performance being reduced to 200-in-1 million.
---------------------------------------------------------------------------

    \6\ Uncertainties regarding the equipment leak emissions, the
uncertainties inherent in all risk assessments (i.e., the emissions
dataset, dispersion modeling, exposure estimates, and dose-response
relationships), and the EPA's use of the 2016 unit risk estimate
(URE) for ethylene oxide (which is developed to be health
protective).
---------------------------------------------------------------------------

    At proposal, we requested comments on the use of the 2016 updated
URE \7\ for ethylene oxide for regulatory purposes beyond those already
received for the Hydrochloric Acid (HCl) Production RTR proposed rule
(84 FR 1584-1597, February 4, 2019), as well as comments on the use of
an alternative URE for ethylene oxide in the final rule for this source
category. We also solicited comment on which of the two ethylene oxide
equipment leak co-proposed control options should be implemented in the
final rulemaking in order to ensure that risks from the source category
are acceptable.
---------------------------------------------------------------------------

    \7\ The URE is an upper-bound estimate of an individual's
incremental risk 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 UREs 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, where available.
In cases where new, scientifically credible dose-response values
have been developed in a manner consistent with 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 pollutant-specific
dose-response values used to estimate cancer health risk are
available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
---------------------------------------------------------------------------

    We then considered whether the existing MACT standards provide an
ample margin of safety to protect public health and whether, taking
into consideration costs, energy, safety, and other relevant factors,
and whether additional standards are required to prevent an adverse
environmental effect. To determine whether the rule provides an ample
margin of safety, we considered the requirements that we proposed to
achieve acceptable risks. We also considered implementing equipment
leak co-proposed Control Option 2, which would require that the two
facilities with estimated cancer risks greater than 100-in-1 million
comply with more stringent standards. In addition, we considered
expanding the applicability of equipment leak co-proposed Control
Option 2 so that the more stringent controls would apply to all
facilities with equipment in ethylene oxide service, regardless of
estimated cancer risks. Finally, we considered the options identified
in the technology review (i.e., controls for equipment leaks for MON
equipment not in ethylene oxide service and heat exchange systems). In
considering whether the standards should be tightened to provide an
ample margin of safety to protect public health, we considered the same
risk factors that we considered for our acceptability determination and
also examined the costs, technological feasibility, and other relevant
factors related to emissions control options that might reduce risk
associated with emissions from the source category. Based on these
considerations, we proposed that the requirements that we proposed to
achieve acceptable risks would also provide an ample margin of safety
to protect public health (section IV.C.4 of the proposal preamble, 84
FR 69182, December 17, 2019). We also solicited comment on which of the
available control options should be applied in order to provide an
ample margin of safety to protect public health.
2. How did the risk review change for the Miscellaneous Organic
Chemical Manufacturing source category?
a. Miscellaneous Organic Chemical Manufacturing Source Category Risk
Assessment
    As part of the final risk assessment, the EPA reanalyzed risks
using emissions inventory updates that were received from a CAA section
114 request issued to the highest risk facility, and additional
information received from the two highest risk facilities during the
public comment period. These updates were primarily reductions to
emissions of ethylene oxide and included revised actual emissions for
two facilities and allowable emissions for one facility. The revised
emissions used to reanalyze risks are available in the docket for this
rulemaking (see section IV.A.3.b of this preamble and Appendix 1 of the
Residual Risk Assessment for the Miscellaneous Organic Chemical
Manufacturing Source Category in Support of the 2020 Risk and
Technology Review Final Rule, available in the docket for this
rulemaking, for more detail about these revised emissions).
    Based on the revised actual emission estimates, the results of the
chronic inhalation cancer risk from the revised risk assessment
indicate that the maximum lifetime individual cancer risk posed by the
194 facilities could be as high as 400-in-1 million, with ethylene
oxide from process vents and equipment leaks as the major contributors
to the risk. Specifically, the revised baseline cancer risk is reduced
to 400-in-1 million for the Lanxess facility, and to less than 100-in-1
million for Huntsman Performance. The total estimated cancer incidence
from the revised risk assessment is 0.1 excess cancer cases per year,
or one excess case in every 10 years. Of the approximately 89,000,000
people that live within 50 kilometers (km) of the 194 facilities,
1,700,000 people were estimated to have cancer risks greater than or
equal to 1-in-1 million from HAP emitted from the facilities in this
source category. Approximately 46,000 people were estimated to have
cancer risks greater than or equal to 10-in-1 million, and 1,200 people
were estimated to have cancer risks greater than or equal to 100-in-1
million. Of those 1,200 people, approximately 860 are estimated to have
cancer risks greater than 100-in-1 million (Table 3 of this preamble).
    The estimated maximum chronic noncancer TOSHI for the source
category remained unchanged from the proposal at 1, indicating low
likelihood of adverse noncancer effects from long-term inhalation
exposures. Additionally, the worst-case acute HQ (based on the REL)
remained unchanged from proposal (6 based on the REL for acrolein and
the next highest dose-response value for acrolein, the AEGL-1, results
in an HQ of 0.2). Similarly, the multipathway risk screening assessment
remained unchanged from proposal and resulted in a maximum Tier 2
cancer SV of 10 for POM for the farmer scenario. The Tier 2 SVs for all
other PB-HAP emitted from the source category (mercury compounds,
cadmium compounds, and arsenic compounds) were less than 1.
    Whole facility risks also did not change from those at proposal
based on revised emission estimates. The maximum lifetime individual
cancer risk based on whole facility emissions was 3,000-in-1 million
driven by ethylene oxide emissions from fugitive emissions and flares
from the Synthetic Organic Chemical Manufacturing, Polyether Polyols
Production, and Miscellaneous Organic Chemical Manufacturing source
categories. The

maximum chronic noncancer HI posed by whole facility emissions was
estimated to be 7 (for the respiratory system as the target organ),
driven by emissions of chlorine and methyl bromide from non-source
category sources identified as brominated organic manufacturing.
    Based on revised allowable emission estimates, the maximum lifetime
individual cancer risk could be as high as 800-in-1 million, with
ethylene oxide from storage tanks, process vents, and equipment leaks
driving the risk. The total estimated cancer incidence is 0.2 excess
cancer cases per year, or 1 excess case in every 5 years. Approximately
2,000,000 people were estimated to have cancer risks greater than or
equal to 1-in-1 million from allowable emissions, approximately 170,000
were estimated to have cancer risks greater than or equal to 10-in-1
million, and 4,200 people were estimated to have cancer risks greater
than or equal to 100-in-1 million. Of those 4,200 people, approximately
1,700 are estimated to have cancer risks greater than 100-in-1 million
(Table 3 of this preamble).

         Table 3--Miscellaneous Organic Chemical Manufacturing Source Category Risk Assessment Results Based on Revised Emissions in Final Rule
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Maximum         Estimated population at        Estimated
                                         individual     increased risk of cancer \2\    annual cancer      Maximum
       Number of facilities \1\          cancer risk  --------------------------------    incidence        chronic     Maximum screening acute noncancer
                                       (in 1 million)     >100-in-1       >=1-in-1       (cases per       noncancer                    HQ
                                             \2\           million         million        year) \2\       TOSHI\2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Actual Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
194..................................             400             860       1,700,000             0.1               1  HQREL = 6
                                                                                (acrolein).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Allowable Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
194..................................             800           1,700       2,000,000             0.2               1  .................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\3\ Actual emissions equal allowable emissions with the exception of one facility, where additional information was available.

    Finally, risks were estimated after application of the controls
finalized in this rulemaking for storage tanks, process vents, and
equipment in ethylene oxide service, in addition to controls that apply
to all HAP and were identified during the technology review (controls
for heat exchangers and equipment leaks for MON equipment not in
ethylene oxide service). Based on these controls, we estimated that the
baseline cancer MIR of 400-in-1 million would be reduced to 200-in-1
million for actual emissions, with ethylene oxide from equipment leaks
driving the risk. There would be 107 people estimated to have a cancer
risk greater than 100-in-1 million, down from 860 people in the
baseline scenario. There is an estimated reduction in cancer incidence
to 0.09 excess cancer cases per year (or one excess case every 11
years), down from 0.1 excess cancer cases per year (or one excess
cancer case every 10 years) in the baseline scenario. In addition, the
number of people estimated to have a cancer risk greater than or equal
to 1-in-1 million would be reduced from 1,700,000 to 1,400,000 (Table 4
of this preamble).
    For allowable emissions, we estimated that the baseline cancer MIR
of 800-in-1 million would be reduced to 200-in-1 million, with ethylene
oxide from equipment leaks driving the risk. There would be 115 people
estimated to have a cancer risk greater than 100-in-1 million, down
from 1,700 people in the baseline scenario. There is an estimated
reduction in cancer incidence to 0.09 excess cancer cases per year (or
one excess case every 11 years), down from 0.2 excess cancer cases per
year (or one excess cancer case every 5 years) in the baseline
scenario. In addition, the number of people estimated to have a cancer
risk greater than or equal to 1-in-1 million would be reduced from
2,000,000 to 1,400,000 (Table 4 of this preamble).

   Table 4--Baseline and Post-Control Risk Summary for the Miscellaneous Organic Chemical Manufacturing Source
                                Category Based on Revised Emissions in Final Rule
----------------------------------------------------------------------------------------------------------------
                                     Inhalation cancer risk                   Population cancer risk
                               ---------------------------------------------------------------------------------
                                    Maximum                           Cancer
                                  individual                         incidence       >100-in-1       >=1-in-1
                                  risk (in 1       Risk driver      (cases per        million         million
                                   million)                            year)
----------------------------------------------------------------------------------------------------------------
                                                Actual Emissions
----------------------------------------------------------------------------------------------------------------
Baseline Risk.................             400  ethylene oxide..             0.1             860       1,700,000
Post-control Risk.............             200  ethylene oxide..            0.09             107       1,400,000
----------------------------------------------------------------------------------------------------------------
                                               Allowable emissions
----------------------------------------------------------------------------------------------------------------
Baseline Risk.................             800  ethylene oxide..             0.2           1,700       2,000,000
Post-control Risk.............             200  ethylene oxide..            0.09             115       1,400,000
----------------------------------------------------------------------------------------------------------------

    We continue to find that the revised risks prior to control are
unacceptable, and we are revising the final NESHAP for the
Miscellaneous Organic Chemical Manufacturing source category pursuant
to CAA section 112(f)(2) on the basis that risks are unacceptable.
However, as discussed in sections IV.A.3 and IV.A.4 of this preamble,
we find that, after implementation of the controls finalized in this
rulemaking, the resulting risks would be acceptable for this source
category and achieve an ample margin of safety.
    Additional details of the reanalyzed risks can be found in the
Residual Risk Assessment for the Miscellaneous Organic Chemical
Manufacturing Source Category in Support of the 2020 Risk and
Technology Review Final Rule, available in the docket for this
rulemaking.
b. Rule Changes
    Based on comments received on the proposed rulemaking, we are
revising the proposed definition of ``in ethylene oxide service'' for
process vents by removing ``undiluted'' from mass-based criteria and
removing the phrase ``anywhere in the process.'' In the final rule, a
process vent in ethylene oxide service means each batch and continuous
process vent in a process that, when uncontrolled, contains a
concentration of greater than or equal to 1 ppmv undiluted ethylene
oxide, and when combined, the sum of all these process vents would emit
uncontrolled, ethylene oxide emissions greater than or equal to 5 lb/yr
(2.27 kg/yr). In addition, based on comments received on the proposed
rulemaking, we are revising the definitions of ``batch process vent''
and ``continuous process vent'' in the final rule to clarify that (1)
the existing 50 ppmv HAP and 200 lb/yr uncontrolled HAP emission cut-
offs do not apply to batch process vents in ethylene oxide service; and
(2) the existing 0.005 weight percent total organic HAP cut-off in 40
CFR 63.107(d) does not apply to continuous process vents in ethylene
oxide service.
    Based on comments received on the proposed rulemaking, we are also
revising the proposed definition of ``in ethylene oxide service'' for
storage tanks by revising the concentration of ethylene oxide criteria
to a 0.1 percent by weight threshold. In the final rule, a storage tank
in ethylene oxide service means a storage tank of any capacity and
vapor pressure storing a liquid that is at least 0.1 percent by weight
of ethylene oxide.
    For equipment leaks in ethylene oxide service, we are finalizing
the co-proposed equipment leak ``Control Option 1.'' We are not
promulgating final amendments for co-proposed equipment leak ``Control
Option 2.''
    Finally, based on comments received on the proposed rulemaking, we
are also revising some of the continuous monitoring requirements for
operating parameters for scrubbers used to control emissions from
process vents in ethylene oxide service or storage tanks in ethylene
oxide service. In the final rule, we are allowing the limits for the
pressure drop across the scrubber and the liquid feed pressure to the
scrubber to be based on the manufacturer's recommendations or
engineering analysis instead of on the performance test. Additionally,
we are changing the continuous compliance requirements for the
operating parameters, such that compliance with the operating parameter
limits is determined on an hourly average basis instead of an
instantaneous basis.
3. What key comments did we receive on the risk review, and what are
our responses?
    This section provides comment summaries and responses for the key
comments received regarding the ethylene oxide IRIS URE, including
those received for the HCl Production RTR proposed rule (84 FR 1584-
1597, February 4, 2019), and our risk assessment for the Miscellaneous
Organic Chemical Manufacturing source category, our proposed definition
of ``in ethylene oxide service,'' proposed requirements for storage
tanks and process vents in ethylene oxide service, and proposed
requirements for equipment leaks in ethylene oxide service. We received
comments in support of and against the proposed residual risk review,
the IRIS URE used in the review, the American Chemistry Council's
(ACC's) request for correction under the Information Quality Act asking
that the ``NATA risk estimates for E.O.\8\ should be withdrawn and
corrected to reflect scientifically supportable risk values,'' and our
determination that additional controls were warranted under CAA section
112(f)(2) for the Miscellaneous Organic Chemical Manufacturing source
category. Other comments on these issues, as well as on additional
issues regarding the residual risk review and the EPA's proposed
changes based on the residual risk review, can be found in the
document, Summary of Public Comments and Responses for the Risk and
Technology Review for Miscellaneous Organic Chemical Manufacturing,
available in the docket for this rulemaking.
---------------------------------------------------------------------------

    \8\ In this instance, ``E.O.'' refers to ``ethylene oxide.''
---------------------------------------------------------------------------

a. Ethylene Oxide IRIS URE
    In the MON RTR proposed rule (84 FR 69182, December 17, 2019), as
well as the HCl Production RTR proposed rule (84 FR 1584, February 4,
2019), we requested comment on the use of the updated ethylene oxide
URE for regulatory purposes. Also, in the proposed rulemaking for the
Miscellaneous Organic Chemical Manufacturing source category, we noted
the ACC's request for correction under the Information Quality Act
asking that the ``NATA risk estimates for E.O. should be withdrawn and
corrected to reflect scientifically supportable risk values.'' Several
commenters provided comments on these two topic areas as summarized
below:
    Comment: We received extensive comments on use of the EPA ethylene
oxide URE. Some commenters were in support of the continued use of the
EPA URE and other commenters recommended changes to aspects of the EPA
URE or recommended use of an alternative to the EPA URE. Many of the
commenters recommending changes to the EPA URE focused on aspects of
dose-response modeling that could affect the value of the EPA URE,
including model selection, inclusion of breast cancer data, cohort
selection, and historical exposure estimates. Other comments evaluated
the biological plausibility of the EPA URE, including considerations of
endogenous and ambient background ethylene oxide levels and mortality
predictions. In some cases, commenters submitted analyses of existing
data, including recent publications (e.g., Marsh et al. 2019; Bogen et
al. 2019; Kirman and Hays 2017). In addition, the Texas Commission on
Environmental Quality (TCEQ) submitted their draft cancer dose-response
assessment for ethylene oxide to the EPA for consideration as an
alternative to the EPA URE for ethylene oxide.
    Response: A number of comments received on aspects of dose-response
modeling largely touch on matters that were identified and discussed as
part of the peer and public review processes for the EPA IRIS ethylene
oxide Assessment, and the Agency considered those comments in the
development of the final IRIS ethylene oxide Assessment.\9\ The prior
comments and responses are documented in the

Appendices of the EPA 2016 IRIS ethylene oxide assessment \10\ and are
therefore addressed here by referencing the existing IRIS responses.
For some of these topics, additional comments were submitted that
either augment previous comments or address specific details of the
final IRIS dose-response model that were not addressed during the peer-
review process. For example, additional comments were submitted on pre-
1978 exposure estimates and statistical evaluation of the dose-response
model selected for lymphoid cancer. Additional detailed responses to
these topics are provided in the response to comment document for this
rulemaking.
---------------------------------------------------------------------------

    \9\ Evaluation of the Inhalation Carcinogenicity of Ethylene
Oxide (EtO), EPA/635/R-16/350fa. Available at https://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=329730.
    \10\ Evaluation of the Inhalation Carcinogenicity of Ethylene
Oxide (EtO) Appendices, EPA/635/R-16/350fb. Available at https://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=329730.
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    Several public comments referred to recent analyses of existing
data, including publications that focus on different aspects of
ethylene oxide assessment such as weight of evidence for breast cancer
(Marsh et al. 2019), estimates of ethylene oxide levels produced in our
bodies (Kirman and Hays 2017), and evaluation of historical
occupational exposure estimates (Bogen et al. 2019). As we detail in
the response to comment document, consideration of these individual
analyses did not prompt the Agency to pursue reassessment of the EPA's
IRIS ethylene oxide Assessment for purposes of this rulemaking. For
example, Marsh et al. analyzed breast cancer mortality and focused on
comparing cancers seen in occupational groups with national or regional
average rates; whereas, the EPA has generally focused on studies of
breast cancer incidence since many women survive breast cancer.\11\
With regard to the amount of ethylene oxide produced within the human
body, Kirman and Hays did not include any direct measurements of
endogenous ethylene oxide levels; however, they did measure a
particular by-product (an adduct--chemical reaction product--with the
protein hemoglobin) that could be associated with total ambient
exposure (including both endogenous and ambient background) among non-
occupationally exposed individuals. While studies of the hemoglobin
adduct found it to be a useful marker for high level occupational
exposures to ethylene oxide, there are many uncertainties in attempting
to use this product as a direct measure of ambient background or
endogenous levels of ethylene oxide in the body. Further, because the
IRIS URE for ethylene oxide represents the increased cancer risk due to
exposure to ethylene oxide emissions above endogenous ethylene oxide
and ambient background levels, consideration of the findings of Kirman
and Hays or other studies of endogenous or ambient background exposures
would not impact the URE. The findings of Bogen et al. are discussed
further in the response to comment document for this rulemaking.
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    \11\ Guidelines for Carcinogen Risk Assessment, EPA/630/P-03/
001F, 2005. Available at: https://www.epa.gov/sites/production/files/2013-09/documents/cancer_guidelines_final_3-25-05.pdf.
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    Though the TCEQ submitted their draft cancer dose-response
assessment for ethylene oxide to the EPA as part of the public comment
process, the assessment had not yet undergone peer review, and the TCEQ
dose-response value had not yet been finalized by the close of the
public comment period for this rulemaking, which closed on March 19,
2020.\12\ Therefore, the TCEQ dose-response value could not be
considered for this rulemaking.
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    \12\ Note that the final TCEQ assessment was issued on May 15,
2020.
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    For these reasons, we have decided to continue to use the EPA URE
for ethylene oxide for the risk analyses performed for this final
rulemaking. As always, the EPA remains open to new and updated
scientific information, as well as new dose response values such as the
TCEQ value, as they become available.
    Comment: Several commenters supported the ACC's request for
correction. Other commenters indicated that there was no justification
for a correction to the EPA URE for ethylene oxide.
    Response: In a letter to the ACC dated December 18, 2019, the then-
acting Assistant Administrator for Air and Radiation stated that
``[b]ecause EPA received comments from the ACC and others on the HCl
proposed rule related to use of information in the 2016 EtO IRIS
Assessment,'' and ``given that EPA anticipates receiving additional
comments focused on the 2016 EtO IRIS Assessment in the MON RTR
rulemaking,'' the EPA believed at that time that it was ``appropriate
to address this [request for correction] as part of the MON RTR
rulemaking.'' \13\ Having now reviewed and considered the comments it
has received, the EPA has determined that it is appropriate to defer
providing a final response to the ACC's request at this time. The EPA
is under a court ordered deadline requiring signature of the final MON
RTR by May 29, 2020, and we have determined that, given the time
available and in light of other resource constraints, completing our
consideration of the Information Quality Act request for correction in
conjunction with taking final action in this rulemaking is not
practicable. Accordingly, in order to ensure that the ACC's request for
correction is given the complete attention it warrants, we have
determined that it is appropriate to issue this final CAA rule
separately from the Agency response to the ACC request. We anticipate
taking final action on the Information Quality Act request for
correction in the near future.
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    \13\ See Letter from Anne L. Idsal, acting Assistant
Administrator for Air and Radiation to William P. Gulledge, American
Chemistry Council (December 18, 2019). Similarly, in the proposed
rulemaking, we took note of the fact that, ``[g]iven the ACC's
Response for Correction,'' we had in the earlier HCl Production RTR
proposed rule ``requested comment on the use of the updated ethylene
oxide URE for regulatory purposes.'' 84 FR 69218 (December 17,
2019). ``Because of the robustness of the comment received and their
relevance to this rulemaking,'' we said that the Agency would
``consider those comments in the final rule for the Miscellaneous
Organic Chemical Manufacturing source category.'' Id.
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b. MON Risk Assessment
    Several commenters provided comments on specific facilities in the
EPA risk assessment and submitted additional data for the EPA to use
for assessing public health risks. Those comments are as follows:
    Comment: One commenter contended that the EPA conducted a CAA
section 114 data collection effort on the highest risk facility,
Lanxess, but did not use the data at proposal, even though the results
of the performance testing were received in September 2019. The
commenter disagreed with the EPA's decision that any changes received
by September 2018 were incorporated into the RTR modeling file, and
after September 2018 and before February 2019, only minor changes
related to MON applicability of ethylene oxide emissions were
incorporated into the RTR modeling file. Commenters stated that the EPA
has significantly overestimated the risks posed by the Lanxess facility
and that if the EPA used the most recent and best available data, the
Lanxess facility would not be classified as a high-risk site. As
justification, the commenters provided new stack test data for Lanxess'
two process scrubbers and the storage tank scrubber based on
performance tests conducted from June 3 to June 20, 2019. The
commenters provided that the preliminary results from the performance
tests indicate that the total ethylene oxide emissions from the three
scrubbers were significantly less than the initial estimate that was
used for the risk analysis and proposed rule.\14\ Commenters observed
that the

risk analysis published at proposal did not include this most recent
stack test data.
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    \14\ Commenter referred to Docket Item No. EPA-HQ-OAR-2018-0746-
0022.
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    One commenter also objected to the EPA using a different approach
to establish baseline emissions for the Lanxess facility as compared
with all other MON facilities and objected to the EPA proposing a more
stringent control technology standard specifically for this facility
based on incomplete data and a different standard from that which was
applied to all other facilities. The commenter reiterated that for the
Lanxess facility, the EPA disregarded actual 2014 emissions data for
storage tanks and process vents and estimated emissions for fugitives
using component counts and emission factors, which the EPA acknowledged
likely resulted in emission estimates that were biased high. The
commenter provided updated information and requested that the facility
emissions, like the other MON facilities, be analyzed based on 2014
actual emissions.
    Some commenters requested that the EPA update the emission estimate
for the site to reflect a control efficiency of 99.9 percent for the
ethylene oxide storage tank scrubber and use 2014 actual emissions
data, which would establish a 0.0107 tpy baseline for this scrubber.
The commenters further asserted that the EPA chose not to use reported
2014 ethylene oxide emissions associated with the two scrubbers that
control emissions from the two process vents in ethylene oxide service
and instead calculated potential emission rates using the facility's
2012 title V application, which resulted in a modeling input of almost
twice the actual emissions and was not consistent with the method the
EPA utilized to review risk for the other MON facilities. The
commenters requested that the EPA use the reported values contained in
the calendar year 2014 emissions inventory for the two process vent
scrubbers to establish the baseline for risk. Commenters further
contested the EPA's approach to estimating fugitive emissions and
emissions from equipment leaks; commenters did not agree with
estimating fugitive emissions based on potential emissions in lieu of
2014 actual emissions. Further, the commenters requested that the EPA
update the equipment leak source parameters to a volume source versus
an area source to better represent equipment leak emissions, and to
update the risk inputs to use current equipment counts, composition of
ethylene oxide in the streams, the emission factors from Table 6 of the
EPA's equipment leak evaluation memorandum, Analysis of Control Options
for Equipment Leaks at Processes that use ethylene oxide Located in the
Miscellaneous Organic Chemical Manufacturing Source Category, and the
facility's actual hours of operation in 2014. The commenters also
stated that the facility has no light liquid pumps in ethylene oxide
service that would be subject to the proposed pump requirements.
    Commenters stated that, using the revised emissions estimates and
volume source parameters, they re-ran the EPA's risk model and
calculated a baseline risk of 270-in-1 million for the Lanxess
facility. The commenter stated that using the revised baseline
emissions to estimate post-control emissions would result in
significant reductions for either Control Option 1 or 2 and provided
revised estimates of post-control emissions based on the updated data.
The commenter asserted that when the EPA risk model is rerun for the
Lanxess facility utilizing all corrected inputs, the residual risk is
100-in-1 million with implementation of Control Option 1.
    Response: In light of the additional data and comments received,
the EPA has made adjustments to the emissions used in the residual risk
assessment in the final rule, and we note that using revised baseline
emissions to estimate post-control emissions results in significant
reductions for either Control Option 1 or 2. As we acknowledged in the
proposal preamble (84 FR 69186, December 17, 2019), although the EPA
did not receive the CAA section 114 data from Lanxess in time to be
used at proposal, we posted this data publicly to the docket at
proposal to provide the public with sufficient time to review the data
and provide comments during the comment period. Further, we
acknowledged we intended to ``use the collected information to assist
the Agency in filling data gaps, establishing the baseline emissions
and control levels for purposes of the regulatory reviews, identifying
the most effective control measures, and estimating the environmental
impacts associated with the regulatory options considered and
reflected.'' (84 FR 69186, December 17, 2019). Thus, as has always been
our intent, we are revising the residual risk assessment to incorporate
the data received in the response to the CAA section 114 request to
update Lanxess' emissions in the final rule, which includes updating
emissions for the storage tank and process vents to reflect the
measured control efficiencies. Additionally, at proposal, the best
available data had us assume that ``actual'' emissions were equal to
``allowable'' emissions. At final, the data acquired from the CAA
section 114 request has allowed us to separately estimate ``actual''
emissions and ``allowable'' emissions at Lanxess. Therefore, in the
final rule, we present both pre-control and post-control risks for
Lanxess considering the range of emissions generated by these two
emissions estimations.
    Additionally, we are incorporating the updated data for equipment
in ethylene oxide service provided during the comment period by Lanxess
in the revised risk assessment for the final rule. The updated data
include component counts, hours of operation, and percentage of
ethylene oxide for each process with equipment in ethylene oxide
service. The EPA believes that the updated data represents the best
available data because it is more recent and reflects updated component
counts and changes made to the process. We considered updating the
source parameters for equipment in ethylene oxide service to reflect a
volume source as the commenter suggested; however, we ultimately
retained the parameters as an area source based on the information
already available to the EPA, and after determining such change would
have minimal impact on risk. After updating emissions for this
facility, the pre-control cancer risks are estimated to be 400-in-1
million (actuals) and 800-in-1 million (allowables). We disagree with
the commenter's assertion that pre-control risks are 300-in-1 million
based on actual emissions. At proposal and in the commenter's revisions
to the modeling file, fugitive ethylene oxide emissions were grouped
together and modeled as being released from one location. In their
comments, Lanxess provided additional information which made it
possible to accurately separate and assign these fugitive ethylene
oxide emissions to their actual locations at the facility. In the
modeling file for the final rule, we have separated and relocated
ethylene oxide fugitive emissions to their proper location, which
resulted in a risk higher than what the commenter estimated due to
several fugitive areas being in closer proximity to the receptor.
Therefore, in the final rule, after considering all updates made to the
emissions data for Lanxess, the ethylene oxide emissions at the current
level of control (i.e., before the amended controls are applied) are
estimated to be approximately 0.64 tpy based on actual emissions and
2.6 tpy based on allowable emissions, compared to 8.8 tpy at proposal.
See Appendix 1 of the Residual Risk Assessment for the Miscellaneous
Organic Chemical Manufacturing Source Category in

Support of the 2020 Risk and Technology Review Final Rule, available in
the docket for this rulemaking, for additional information.
    After ethylene oxide-specific controls for process vents, storage
tanks, and equipment leak Control Option 1 are applied at Lanxess,
ethylene oxide emissions are expected to be reduced to 0.15 tpy based
on actual emissions and 0.17 tpy based on allowable emissions.
Estimated post-control cancer risks are reduced to 200-in-1 million for
both actual and allowable emissions estimates. We disagree with the
commenter's assertion that post-control risks at Lanxess after applying
controls for process vents, storage tanks, and equipment leak Control
Option 1 are 100-in-1 million based on actual emissions, since the
commenter did not model fugitive emissions from their actual locations
as described above. In addition, Lanxess also provided updated
component counts in their comments that we used to update the estimated
effect that controls would have in reducing ethylene oxide emissions.
These new emission reduction estimates indicate that the revised leak
detection and repair (LDAR) requirements for light liquid pumps will
have less of an effect in reducing ethylene oxide emissions than
estimated at proposal, due to new knowledge that there are no light
liquid pumps in ethylene oxide service at Lanxess. After ethylene
oxide-specific controls for process vents, storage tanks, and equipment
leaks Control Option 2 are applied, and using updated emissions data
provided during the comment period, estimated post-control cancer risks
are reduced to 100-in-1 million (actuals and allowables).
    We note that, after the comment period closed, the EPA met with
representatives from Lanxess on March 25, 2020, to discuss their
comments posted to the docket on February 20, 2020, (see Docket Item
No. EPA-HQ-OAR-2018-0746-0069) and ask clarifying questions.
Subsequently, Lanxess provided written responses to these questions on
April 17, 2020, as well as additional updates to their February
comments that included further revisions to emissions data, which would
affect equipment leak emissions estimates. This data was not received
in time to incorporate into the final risk modeling; however, we
recognize that these changes would further reduce estimated ethylene
oxide emissions from equipment leaks. Meeting minutes for the March
discussion between the EPA and Lanxess, as well as the written
responses Lanxess provided to questions asked at this meeting, can be
found in the memorandum, Meeting Record for March 25, 2020, Meeting
Between the U.S. EPA and Representatives of Lanxess Corporation, in the
docket for this rulemaking.
    Comment: Several commenters provided input on the emissions
estimates used in the risk modeling for the Huntsman Performance
facility in Conroe, Texas. One commenter stated that the EPA's
emissions estimates for the facility from the 2014 National Emissions
Inventory (NEI) and the 2014 Toxics Release Inventory (TRI) are not
appropriate for use in a risk assessment. The commenter argued that
even if the NEI and TRI data were developed with adequate specificity
to support risk modeling, the data are 6 years old and do not reflect
current operations. The commenter provided data for the Huntsman
Performance facility that they claimed more accurately reflect ethylene
oxide emissions from equipment leaks, based on a detailed analysis
using direct quarterly LDAR monitoring data for each relevant
component. Another commenter recommended that the EPA use the
information provided in Huntsman Performance's comments in the final
rule because the new data more accurately reflect ethylene oxide
emissions at the Huntsman Performance facility. Commenters stressed
that the submitted data significantly improve on the 2014 data because
they reflect physical and operating changes made since 2014, such as
addition and removal of relevant equipment. One commenter explained
that the new data submitted remain highly conservative and are expected
to overstate actual ethylene oxide emissions, largely because the
commenter's data analysis does not assume that results below the
detection limit are equal to ``zero'' but are present at the detection
limit.
    Some commenters stated that the EPA's modeling files incorrectly
included sources at the Huntsman Performance facility that are not MON-
applicable. One commenter asserted that the EPA's risk assessment for
the Huntsman Performance facility incorrectly designates certain units
with ethylene oxide emissions as being regulated under MON, despite the
fact that they are not MON sources. Commenters also stated that the EPA
specifically notes that these ethylene oxide equipment leak emissions
are not entirely from MON processes; however, the EPA did not have
enough information to distinguish between emissions attributed to MON
processes versus other processes (e.g., 40 CFR part 63, subparts H and
PPP). The commenter specifically identified the railcar unloading
fugitive area and tank farm fugitives as inappropriate to include as
MON sources and provided input on why the sources do not meet the
definition of MCPU or storage tank or fall within the purview of the
MON. The commenter provided a copy of revised modeling they conducted
with the updated emissions estimates and removal of units not subject
to MON; the commenter's revised modeling results showed that residual
risks associated with the Huntsman Performance facility are 40-in-1
million.
    Response: The EPA has reviewed the updated equipment leak emissions