Document ID: EPA-HQ-OAR-2018-0746-0170
Agency: epa
Document Type: Rule
Title: National Emission Standards for Hazardous Air Pollutants: Miscellaneous Organic Chemical Manufacturing Residual Risk and Technology Review
Posted Date: 2020-08-12T04:00Z

[Federal Register Volume 85, Number 156 (Wednesday, August 12, 2020)]
[Rules and Regulations]
[Pages 49084-49167]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-12776]

[[Page 49083]]

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  

[[Page 49084]]

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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: (919) 541-5110; and email address: 
lavoie.tegan@epa.gov. 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: (919) 541-1535; 
and email address: woody.matthew@epa.gov. 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: (202) 564-1395; and email 
address: cox.john@epa.gov.

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

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

[[Page 49085]]

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

[[Page 49086]]

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

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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

[[Page 49088]]

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.

[[Page 49089]]

    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

[[Page 49090]]

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

[[Page 49091]]

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.

[[Page 49092]]

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

[[Page 49093]]

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

[[Page 49094]]

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

[[Page 49095]]

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

[[Page 49096]]

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
----------------------------------------------------------------------------------------------------------------

[[Page 49097]]

    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

[[Page 49098]]

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.
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    \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.
---------------------------------------------------------------------------

    \12\ Note that the final TCEQ assessment was issued on May 15, 
2020.
---------------------------------------------------------------------------

    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

[[Page 49099]]

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

[[Page 49100]]

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 
data provided during the comment period by Huntsman Performance in 
Conroe, Texas, the second highest risk-driving facility that was 
identified at proposal. We agree with the information provided that two 
emission units were incorrectly modeled as being subject to MON, when 
in fact, they are subject to other standards. As such, in the final 
rule these units are modeled at the whole facility-level only. We have 
also updated Huntsman Performance's ethylene oxide equipment leak 
emissions using the updated emissions data provided by the facility, 
consistent with the EPA's standard practice of using the best available 
data. The EPA believes that the updated data represents the best 
available data because it is more recent (i.e., 2019), is based on 
actual emissions measurements, reflects recent physical and operating 
changes made to the process since the 2014 NEI emissions were reported, 
and conservatively considers results below the detection limit as being 
present at the detection limit. After considering all updates made to 
the emissions data for Huntsman Performance, the ethylene oxide 
emissions before controls are applied are estimated to be approximately 
0.03 tpy based on actual and allowable emissions, compared to roughly 
0.26 tpy estimated at proposal. The pre-control cancer risks are 
estimated to be 20-in-1 million. After ethylene oxide-specific controls 
are applied, the estimated post-control cancer risks are also 20-in-1 
million. Risks are not reduced with the amendments because (1) storage 
tank and process vent controls have no effect since these are not 
sources of ethylene oxide emissions at this facility, and (2) equipment 
leak Control Option 1 has no effect because this facility already meets 
the LDAR requirements this option requires.
    We note that, after the comment period closed, the EPA met with 
representatives from Huntsman Performance on March 12, 2020, to

[[Page 49101]]

discuss their comments posted to the docket on February 20, 2020, (see 
Docket Item No. EPA-HQ-OAR-2018-0746-0073) and ask clarifying 
questions. Subsequently, Huntsman Performance provided written 
responses to these questions on April 27, 2020. The information 
received in their April response further supports their prior assertion 
from their February 2020 comments that the two units modeled as being 
subject to MON at proposal should instead be modeled only at the whole 
facility level and provides additional information related to 
wastewater operations at the facility. No changes to facility emissions 
or the risk assessment were made as a result of the April 2020 
responses, beyond the changes already made based on their comments 
submitted in February 2020. Meeting minutes for the referenced 
discussion between the EPA and Huntsman Performance, as well as the 
written responses Huntsman Performance provided in April 2020 to the 
questions asked at this meeting, can be found in the memorandum, 
Meeting Record for March 12, 2020, Meeting Between the U.S. EPA and 
Representatives of Huntsman Performance, in the docket for this 
rulemaking.
    Several commenters provided comments on the EPA's risk 
acceptability and ample margin of safety determinations. Those comments 
are as follows:
    Comment: Several commenters agreed with the EPA's determination 
that the proposed emission standards for this source category would 
achieve an acceptable risk level and protect public health with an 
ample margin of safety. One commenter in support of the finding stated 
that the Benzene NESHAP rulemaking expressly notes that ``[t]he 
presumptive level provides a benchmark for judging the acceptability of 
maximum individual risk (``MIR''), but does not constitute a rigid line 
for making that determination.'' \15\ The commenter stated that, in the 
Benzene NESHAP itself, the EPA found MIRs for two categories that 
exceeded the standard 1-in-10,000 (100-in-1 million) presumptive 
benchmark acceptable (200-in-1 million for Coke By-Product Recovery 
Plants and 600-in-1 million for Equipment Leaks) based on uncertainties 
in the data that suggested risks were overstated. The commenter 
expressed that this precedent means that the EPA has authority to 
accept a MIR that is above a 1-in-10 thousand (100-in-1 million) 
benchmark, and that scientific uncertainty and the likely overstatement 
of risks is a reasonable basis for doing so. The commenter stated that, 
therefore, the EPA should make a similar acceptability determination 
for the MON RTR rulemaking, given that comparable uncertainties exist 
with the information and emissions estimates informing the risk 
modeling.
---------------------------------------------------------------------------

    \15\ Commenter provided the following reference: 54 FR 38045, 
September 14, 1989.
---------------------------------------------------------------------------

    However, other commenters questioned the justification for 
proposing a regulation that would still allow a cancer risk of 200- to 
300-in-1 million. One commenter stated that failing to set a health-
protective emission standard that eliminates unacceptable risk because 
a risk factor ``could be'' lower is arbitrary and unlawful under CAA 
section 112(f)(2). Other commenters said they believed that the 100-in-
1 million lifetime cancer risk cannot be considered safe or 
``acceptable,'' and multiple commenters recommended that the EPA ensure 
risks from ethylene oxide exposure are below 100-in-1 million. Two 
commenters insisted that no level of health risks from HAP can be 
presumed safe or ``acceptable'' and that the EPA must reduce risks to 
the lowest possible level.
    Other commenters stated that the EPA must require companies to take 
steps necessary to prevent all unacceptable health threats and to 
provide an ``ample margin of safety to protect public health.'' 
Commenters further argued that the EPA did not establish an ``ample 
margin of safety'' between what the EPA considers to be an acceptable 
level of risk and the current emission limits, taking into account the 
nature of the chemicals being emitted and the uncertainties in the 
EPA's risk assessments, as required under CAA section 112(f)(2). The 
commenter argued that the EPA has not shown that it has considered 
whether the uncertainties regarding its health risk assessment require 
a stronger standard.\16\
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    \16\ Commenter provided the following reference: NRDC, 824 F.2d 
at 1165 (``Congress . . . recognized in section 112 that the 
determination of what is `safe' will always be marked by scientific 
uncertainty and thus exhorted the Administrator to set emission 
standards that will provide an `ample margin' of safety.'').
---------------------------------------------------------------------------

    Response: We agree with commenters that baseline risks for the 
Miscellaneous Organic Chemical Manufacturing source category were 
unacceptable. However, we disagree with commenters who objected to our 
determinations of risk acceptability and ample margin of safety after 
implementation of proposed controls. As explained in the preamble to 
the proposed rule (84 FR 69182, December 17, 2019), section 112(f)(2) 
of the CAA expressly preserves the EPA's use of the two-step process 
for developing standards to address residual risk and interpret 
``acceptable risk'' and ``ample margin of safety'' as developed in the 
Benzene NESHAP (54 FR 38044, September 14, 1989). As explained in the 
Benzene NESHAP, ``the first step judgment on acceptability cannot be 
reduced to any single factor'' and, thus, ``[t]he Administrator 
believes that the acceptability of risk under section 112 is best 
judged on the basis of a broad set of health risk measures and 
information.'' 54 FR 38046, September 14, 1989. Similarly, with regard 
to the ample margin of safety determination, ``the Agency again 
considers all of the health risk and other health information 
considered in the first step. Beyond that information, additional 
factors relating to the appropriate level of control will also be 
considered, including cost and economic impacts of controls, 
technological feasibility, uncertainties, and any other relevant 
factors.'' Id. As also explained in the preamble to the proposed rule 
(84 FR 69182, December 17, 2019), the EPA has adopted this approach in 
its residual risk determinations, and the Court has upheld the EPA's 
interpretation that CAA section 112(f)(2) incorporates the approach 
established in the Benzene NESHAP into the statute. See NRDC v. EPA, 
529 F.3d 1077, 1083 (D.C. Cir. 2008).
    As discussed previously, we have revised the residual risk 
assessment for the final rule to incorporate additional data received 
from a CAA section 114 request, as well as updated emissions data for 
ethylene oxide received during the public comment period, for the two 
facilities with cancer risks greater than 100-in-1 million at the time 
of proposal. Revisions to the risk assessment incorporate the best 
available data and result in an improved assessment of the risks from 
these sources. The revised risk assessment (documented in the Residual 
Risk Assessment for the Miscellaneous Organic Chemical Manufacturing 
Source Category in Support of the 2020 Risk and Technology Review Final 
Rule, which is available in the docket for this rulemaking) shows that, 
both before and after application of Control Option 1, seven of the 
eight facilities with equipment in ethylene oxide service have 
estimated cancer risks below the 100-in-1 million benchmark. After 
application of controls for process vents, storage tanks, and equipment 
leak Control Option 1 as required by this final rule, the remaining 
facility,

[[Page 49102]]

Lanxess, has estimated cancer risks of 200-in-1 million.
    Regarding the post-control cancer risks of 200-in-1-million, based 
on the revised risk assessment, we note that 100-in-1 million cancer 
risk is not a bright line indicating that risk is ``acceptable.'' As 
noted by commenters, the EPA has previously accepted MIRs that exceeded 
100-in-1 million (i.e., 200-in-1 million in the Benzene NESHAP, 54 FR 
38047; 200-in-1 million in the National Emission Standards for Coke 
Oven Batteries, 70 FR 19993; and 200-in-1 million in the National 
Perchloroethylene Air Emissions Standards for Dry Cleaning Facilities, 
71 FR 42731). We note that one commenter claimed that the EPA found a 
cancer risk as high as 600-in-1 million acceptable for equipment leaks 
in the Benzene NESHAP. This is inaccurate. A 600-in-1 million risk 
estimate was discussed in the proposed Benzene NESHAP. However, this 
estimate was found to be based on outdated emissions and, in the final 
Benzene NESHAP, the EPA noted that while it did not have enough time to 
do so, if it had estimated risks based on updated emissions 
information, risks were expected to be approximately 100-in-1 million; 
this was the basis for the risk acceptability determination (54 FR 
38048).
    When considering risk acceptability, the EPA considers all of the 
health risk information and the associated uncertainties (e.g., 
uncertainties in emissions, relevant health effects information), as 
well as the inherent health protective nature of our risk assessment 
methods. For example, many of the dose-response values we use for HAP 
are considered plausible upper-bound estimates. For the revised risk 
assessment for this source category, the risk driver was ethylene 
oxide, and we used the 2016 EPA IRIS URE for ethylene oxide to 
calculate increased cancer risk. As noted in the preamble to the 
proposed rule, the modeled cancer risks due to emissions of ethylene 
oxide are sensitive to the URE applied. For EPA's 2016 ethylene oxide 
URE, the memorandum, Sensitivity of Ethylene Oxide Risk Estimates to 
Dose-Response Model Selection, which is available in the docket for 
this rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-0027) and 
discussed at length in the proposal preamble, highlighted two key 
aspects (i.e., upper-bound estimate and dose-response model) 
potentially contributing to the conservative (i.e., health protective) 
nature of the final 2016 URE. When taken into account, these two 
aspects provide important context for interpreting risks remaining 
post-control and indicate that the risks are acceptable.
    Furthermore, we note that few people are exposed to cancer risks 
greater than 100-in-1 million, one of the components of health risk 
information considered when estimated cancer risks exceed the 
presumptive benchmark of 100-in-1 million. We estimate that, of the 
89,000,000 people living within 50 km of a source category facility, 
107 (0.0001 percent) would be exposed to levels greater than 100-in-1 
million due to emissions from the source category. We also note that 
the number of people exposed to risks above 100-in-1 million is similar 
to other rules where risks above 100-in-1 million were found to be 
acceptable (100 people in the Benzene NESHAP, 54 FR 38047; 70 people in 
the National Emission Standards for Coke Oven Batteries, 70 FR 19993; 
and two people in the National Perchloroethylene Air Emissions 
Standards for Dry Cleaning Facilities, 71 FR 42731). We also note that 
the cancer incidence (0.09), while higher than the estimated incidence 
for Dry Cleaning Facilities (0.002), is comparable to cancer incidence 
used in acceptability determinations for the Benzene NESHAP (0.05) and 
for Coke Oven Batteries (0.06), despite considerably more facilities in 
this source category (194) compared to the others (12, 36, and four 
facilities, respectively). Also, the percentage of people exposed to 
cancer risks greater than or equal to 1-in-1 million (2 percent of the 
population living near a facility) is within the range of other rules 
such as the Benzene NESHAP (0.4 percent) and Coke Oven Batteries (12 
percent).
    Finally, no other safe controls were identified to further reduce 
risks. While equipment leak Control Option 2 for equipment in ethylene 
oxide service was considered, based on comments and information 
received on the proposed rule, it would not be appropriate to apply to 
equipment in ethylene oxide service due to concerns of explosions. 
Additional details on comments received and our response for equipment 
leak Control Option 2 are provided in section IV.A.3.c of this 
preamble.
    Therefore, we disagree with commenters that maintain that the EPA 
should ensure that the MIR is substantially below the presumptive 
benchmark of 100-in-1 million, or that the EPA must prevent all 
unacceptable health risks. Considering all of the relevant health risk 
information and factors discussed in the Benzene NESHAP and presented 
in the proposal preamble, including the uncertainties discussed in 
section III of the proposal preamble (i.e., the emissions dataset, 
dispersion modeling, exposure estimates, and dose-response 
relationships), the EPA's use of the 2016 IRIS URE for ethylene oxide 
(which is developed to be health protective), and concerns raised by 
commenters, we conclude that the risks from HAP emissions for the 
Miscellaneous Organic Chemical Manufacturing source category, after 
application of the requirements that we are adopting, including 
application of the ethylene oxide-specific controls, will achieve 
acceptable risks for this source category and provide an ample margin 
of safety to protect human health (consistent with the Benzene NESHAP 
framework).
c. Rule Changes
    Comment: Commenters requested that the EPA reconsider the ethylene 
oxide thresholds for storage tanks and process vents identified in the 
proposed definition of ``in ethylene oxide service'' because the 
thresholds the EPA has proposed for defining process vents and storage 
tanks in ethylene oxide service would encompass far more storage tanks 
and process vents than the EPA has accounted for in the rulemaking 
record. The commenters explained that ethylene oxide is used as a 
reactant/intermediate in the production of a wide variety of chemicals. 
The commenters added that because these chemicals are made with 
ethylene oxide, they may contain small residual amounts of unreacted 
ethylene oxide at concentrations much less than 0.1 percent. The 
commenters said that even such low amounts of ethylene oxide would 
represent ``knowledge that ethylene oxide could be present'' in a 
number of process vents and storage tanks far beyond the number of 
facilities identified in the rulemaking record. The commenters stated 
that if finalized the requirement would likely result in a significant 
number of storage tanks being subject to the ethylene oxide 
requirements for which the EPA did not estimate the costs of control or 
other compliance burden in their impacts analysis. Instead, the 
commenters recommended revising the threshold to 0.1 percent by weight 
for storage tanks; and noted that setting the concentration threshold 
to 0.1 percent by weight as an annual average is consistent with the 
``de minimis'' concentration threshold applicable to toxic chemical 
release reporting under 40 CFR part 372 and the hazardous chemical 
inventory reporting requirements under the Emergency Planning and 
Community Right-To-Know Act (EPCRA). The commenters stated that 
suppliers are not required to inform receiving companies of the

[[Page 49103]]

potential presence of ethylene oxide at levels in the 1 ppmw to 1,000 
ppmw (0.1 percent) range; and facilities routinely report under these 
programs and that standardizing the definition of ``in ethylene oxide 
service'' will allow facilities to continue to use their current 
chemical inventory tracking systems to determine whether ethylene oxide 
could potentially be present.
    Some commenters also supported revising the threshold to 0.1 
percent by weight for process vents. Other commenters supported 
regulating process vents where the concentration of ethylene oxide 
exceeds 20 ppmv on an annual average basis at the point of discharge to 
the atmosphere or the point of entry into a control device. The 
commenters noted that setting a 20 ppmv threshold for a vent to be 
considered as being in ethylene oxide service would still be 
sufficiently protective and would require what are now Group 2 
continuous or batch process vents to be controlled. Some commenters 
also suggested raising the 5 lb/yr mass threshold and clarifying where 
process vent characteristics should be determined (after the last 
recovery device but prior to the inlet of any control device that is 
present and prior to release to the atmosphere). Several commenters 
objected to the phrase in the proposed rule definition of ``in ethylene 
oxide service'' as it relates to process vents that, when uncontrolled, 
contains a concentration of greater than or equal to 1 ppmv undiluted 
ethylene oxide ``anywhere in the process,'' 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). 
Commenters questioned the use of the term ``undiluted'' as part of the 
mass emission criteria. One commenter also asked for clarification that 
some process vents may remain uncontrolled as long as the ethylene 
oxide from all process vents (controlled and uncontrolled) is less than 
5 lb/yr and also asked the EPA to clarify that the 5 lb/yr is on an 
MCPU-by-MCPU basis.
    Response: After consideration of these comments, we agree that 
storage tanks containing less than 1,000 ppmw of ethylene oxide (less 
than 0.1 percent by weight) should not be considered in ethylene oxide 
service. We agree that a 1,000 ppmw threshold that also corresponds to 
the chemical inventory reporting requirements under EPCRA and other 
supplier notification requirements does reduce the uncertainty for the 
regulated community and eliminates the burden of performing analyses to 
demonstrate compliance with the rule, while preserving the emissions 
reductions associated with continuing to regulate those storage tanks 
containing significant amounts of ethylene oxide. The 1,000 ppmw 
threshold is also identical to the ``in ethylene oxide service'' 
criterion for applicability to the ethylene oxide-specific requirements 
for equipment leaks, which should also streamline applicability 
determinations for process equipment, piping, and storage tanks. 
Because of its reactivity, ethylene oxide is stored either as a pure 
component or in solution with other material in very low concentrations 
(e.g., at impurity levels). We agree with commenters that emissions 
from tanks storing impurity levels of ethylene oxide are very low and 
do not result in additional risk. We agree that raising this threshold 
will reduce the cost of compliance for those facilities that may store 
and use a chemical that contains ethylene oxide at very low levels but 
for which emissions are negligible. We are also not providing 
additional constraints or clarifications on the determination of the 
threshold (e.g., providing averaging times) for this revised threshold 
as we believe it is no longer needed and note that the EPCRA and 
supplier notifications will generally be the basis for applicability 
determinations.
    We are not revising the threshold for process vents. First, we do 
not support the same threshold for process vents as tanks (1,000 ppmw), 
as some commenters suggest, because this value would essentially exempt 
all ethylene oxide-containing process vents that we have information on 
in the source category and would, therefore, not result in any 
reductions in emissions or risks. Other commenters have suggested a 
lower threshold of 20 ppmv ethylene oxide. We note that the process 
vent ethylene oxide concentrations measured in response to the CAA 
section 114 request ranged from 4 ppmv to 120 ppmv, and the 
quantifiable detection limit was below 0.5 ppmv. Therefore, we consider 
the proposed 1 ppmv threshold reasonable in terms of being measurable 
and quantifiable and also appropriate for the vent stream 
characteristics we intended to regulate that resulted in risk 
reductions. We also are not revising the 5 lb/yr mass threshold for the 
process vents, as the commenters did not suggest an alternative value 
to the mass-based threshold, although we agree that it was our intent 
that it be applied on an MCPU-by-MCPU basis. We also are not finalizing 
suggested provisions for sampling sites to remain consistent with the 
current MON requirements regarding the determination of uncontrolled 
emissions as they apply to both batch and continuous process vents. The 
location for determining the concentration and mass threshold is 
already provided in the MON, which includes ``the point of discharge to 
the atmosphere or the point of entry into a control device'' as the 
location of the process vent. For this reason, we are also revising the 
definition of ``in ethylene oxide service'' to remove the phrase 
``anywhere in the process'' to clarify, as we have adequately specified 
the point at which the process vent characteristics should be 
evaluated. Finally, we have also removed the phrase ``undiluted'' from 
the mass-based criteria in the definition of in ethylene oxide service 
as we agree it does not apply to a mass-based threshold.
    Comment: One commenter contended that the preamble discussion and 
proposed language in the rule is unclear as to whether the existing 
0.005 weight percent total organic HAP cut-off in 40 CFR 63.107(d) of 
the continuous process vent definition (as referenced by the MON's 
continuous process vent definition in 40 CFR 63.2550) and the 50 ppmv 
HAP and 200 lb/yr uncontrolled HAP emission cut-offs in the batch 
process vent definition in 40 CFR 63.2550 still apply relative to the 
definition of ``in ethylene oxide service'' for process vents. The 
commenter requested the EPA confirm that since there is not specific 
language in the rule eliminating these exemptions for continuous and 
batch process vents in ethylene oxide service, we assume that the 
exemptions could still potentially apply. The commenter explained their 
interpretation of the proposed rule is that before the ethylene oxide 
requirements for process vents apply, the gas stream or emission stream 
must first meet the ``continuous process vent'' or ``batch process 
vent'' definition in 40 CFR 63.2550.
    Response: The commenter is incorrect in their interpretation. In 
the proposed and final rule, process vents in ethylene oxide service 
are defined separately, and the existing 0.005 weight percent total 
organic HAP cut-off in 40 CFR 63.107(d) of the continuous process vent 
definition (as referenced by the MON's continuous process vent 
definition in 40 CFR 63.2550) and the 50 ppmv HAP and 200 lb/yr 
uncontrolled HAP emission cut-offs in the batch process vent definition 
in 40 CFR 63.2550 do not apply to the definition of ``in ethylene oxide 
service'' for process vents. Nevertheless, we are clarifying the 
definitions of ``batch process vent'' and ``continuous process vent'' 
in the final rule to make clearer that these cut-offs

[[Page 49104]]

do not apply to process vents in ethylene oxide service. We note that 
process vents could contain HAP other than ethylene oxide, and, 
therefore, it is possible that a process vent could be both in ethylene 
oxide service and also considered a Group 1 or Group 2 process vent. 
Owners or operators should consider all definitions that may apply as 
well as all control requirements when evaluating applicability and 
compliance obligations.
    Comment: In response to our request for comment on the co-proposed 
Control Options for equipment leaks in ethylene oxide service, some 
commenters supported requiring equipment leak Control Option 2 for 
equipment in ethylene oxide service because health risks are 
unacceptable. One commenter contended that the EPA allowing the 
residual risks from these two highest risk facilities to be above the 
EPA's acceptable cancer risk level of 100-in-a-million, after leak 
controls, would set an unsatisfactory precedent for future RTRs. The 
commenter suggested that the EPA consider this an iterative process 
with regards to leak controls and pursue the goal of further reducing 
risks below the 100-in-a-million cancer risk level. Other commenters 
requested that the EPA apply Control Option 2 to all facilities in 
ethylene oxide service.
    Some commenters did not support either equipment leak Control 
Option 1 or 2 for equipment in ethylene oxide service, but if the EPA 
were to finalize one of the options, they would prefer Control Option 1 
with modifications. One commenter contended that the risks from the two 
facilities are substantially overstated so neither option is necessary, 
but Control Option 1 would be sufficient to reduce risks. Some 
commenters opposed the use of leakless valves in Control Option 2 for 
ethylene oxide service because of safety concerns. The commenters 
contended that leakless valves are more likely to trap ethylene oxide 
in valve cavities, and stagnant ethylene oxide polymerizes, creating 
heat that can cause explosions. The commenters added that the EPA 
inadequately addressed these safety issues and cited no actual 
experience with such designs in ethylene oxide service.
    Commenters contended that the EPA's cost analysis for leakless 
valves significantly underestimates costs. One commenter added that the 
EPA's estimate does not include costs for engineering analysis or 
installation of valves, which are typically 2 to 3 times the equipment 
cost. One commenter added that engineering costs could be significant 
as bellows valves are heavier than existing equipment and evaluation 
for additional piping supports would be required, and the larger size 
of these valves would likely require reconfiguration and refabricating 
process piping for required clearance. The commenter continued that 
replacing existing valves with leakless valves will require an extended 
process shutdown to clear and purge the process and then replace the 
valves and that the EPA provides no information on the time to do this 
or the cost to affected companies of lost production.
    Response: We agree that Control Option 1 for equipment in ethylene 
oxide service would sufficiently reduce risks, and we are finalizing 
Control Option 1 in the final rule, except as discussed later in this 
section of the preamble, 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), and any release event from PRDs in ethylene oxide service is a 
deviation of the standard. During the comment period, commenters 
provided updated information on their facilities, including specific 
information regarding sources in their facility that are subject to the 
MON, emissions from each source, controls in use, and operating 
information. We updated the risk assessment for the two facilities 
that, at proposal, had a MIR greater than 100-in-1 million. As 
discussed previously in this section of the preamble, after application 
of the ethylene oxide-specific controls for process vents, storage 
tanks, and equipment leaks from co-proposed Control Option 1, we find 
that the revised risks are acceptable and that the final standards will 
achieve an ample margin of safety to protect human health.
    We reviewed whether Control Option 2 would provide additional 
emission reductions but determined that Control Option 2 was not 
appropriate to apply to equipment in ethylene oxide service based on 
comments and information received on the proposed rule. First, we 
reviewed the comments and information provided by the commenters and 
agree that there are potential safety concerns with the use of leakless 
valves for ethylene oxide service. We agree that many leakless valve 
designs, such as bellows seal valves, have extended packing cylinders, 
which have more volume and areas where ethylene oxide can be trapped 
and polymerize, resulting in the valve stem to stop working and the 
potential for explosions. No information was provided by commenters or 
identified from our review of available data for other sources that 
indicated that leakless valves are being or have been used for ethylene 
oxide service. Because of the safety concerns and no evidence that 
leakless valves are successfully being used for ethylene oxide service 
at this time, the final rule does not require their use. The current 
MON rule already requires gas and light liquid valves to be monitored 
at a leak definition of 500 ppm, and we did not propose different leak 
definitions for valves as part of Control Option 1. Secondly, although 
leakless pumps have been used instead of light liquid pumps for 
processes in ethylene oxide service, new data obtained during the 
comment period from Lanxess indicated that this facility does not have 
pumps in light liquid service that would be subject to the leakless 
pump requirement. Therefore, a requirement to install leakless pumps 
for light liquid pumps would not result in any changes to the estimated 
risks. As a result of the comments and information received and the 
results of the revised Risk Assessment, we are finalizing Control 
Option 1 for equipment leaks.
    Comment: Several commenters disagreed with the operating parameters 
we proposed to require be continuously monitored for scrubbers used to 
control emissions from process vents and storage tanks in ethylene 
oxide service. Several commenters noted that column pressure drop is a 
reliable measurement for scrubbers that can identify flooding 
conditions, but may not identify channeling conditions, when scrubber 
efficiency is depleted as gas flow ``channels'' around the liquid 
blowdown. One commenter contended that background documents in the 
rulemaking docket do not have any justification for requiring a maximum 
pressure drop as an operating parameter limit, but speculated that the 
EPA had proposed a maximum to address a decrease in removal efficiency 
due to plugging or fouling of the packed bed. Commenters stated that 
engineering design should be allowed for establishing the critical 
process parameters for monitoring. One commenter stated that setting 
the maximum operating limit as the average measured during the 
performance test is impracticable because the pressure drop during the 
performance test will be measured when the packing material is 
cleanest. The commenter added that over time the packing material may 
foul and pressure drop may increase, but not to an extent which causes 
decreased performance. The commenter continued that the pressure drop 
will increase as

[[Page 49105]]

either gas flow or liquid flow through the scrubber increases. The 
commenter added that the requirement to operate below a maximum 
pressure drop conflicts with the requirement to operate above a minimum 
liquid to gas ratio. The commenter concluded that if the EPA retains 
the requirement to operate below a maximum pressure drop in the final 
rule, facilities should be allowed to set the maximum pressure drop 
based on manufacturer's recommendations or an engineering evaluation, 
not the average pressure drop measured during the most recent 
performance test.
    Additionally, several commenters contended that monitoring liquid 
feed pressure is redundant with monitoring liquid-to-gas ratio and 
should not be included in the final rule. Commenters contend that 
monitoring feed pressure is an indirect method to assess scrubber 
liquid supply, while monitoring the scrubber liquid-to-gas ratio 
requires direct measurement of the liquid inlet flow rate.
    Response: The EPA is maintaining the requirement to monitor 
pressure drop across the scrubber and liquid feed pressure to the 
scrubber in the final rule. As commenters note, pressure drop across a 
scrubber is a valuable piece of information on the operation of the 
scrubber. It can indicate issues with flooding, plugging, channeling, 
and fouling of the control device. However, we do agree with commenters 
that it may be challenging to establish the maximum pressure drop at 
the same time as the minimum liquid-to-gas ratio is established. The 
liquid-to-gas ratio is the primary parameter of concern in a typical 
wet scrubber system because it ensures that there is enough liquid 
available to clean the gas flowing through the system. Therefore, while 
we are maintaining the requirement to monitor pressure drop across the 
scrubber, in the final rule, we are allowing a pressure drop range to 
be established based on the manufacturer's recommendation or 
engineering analysis.
    We disagree with commenters that the liquid feed pressure is 
redundant to the liquid flow rate. While the liquid feed pressure 
should indicate that liquid is flowing in the system, liquid feed 
pressure is also important for determining that the liquid is being 
appropriately dispersed within the scrubbing system, which is not 
something that the liquid flow rate alone can indicate. We think that 
ensuring the dispersion of the liquid stream is especially critical in 
ethylene oxide control, in order to ensure that the ethylene oxide 
adsorbs into the liquid stream so that it can undergo the conversion 
reaction. However, we are also aware that increases in liquid feed 
pressure can also be caused by blockages in the nozzle, and as such, 
the minimum pressure could be met without the nozzle properly atomizing 
the liquid stream. While we continue to believe that this is an 
important operating parameter for ethylene oxide scrubbers, we believe 
that this parameter does not necessarily need to be based on the 
performance test, and that the manufacturer should be able to provide 
information on what pressure in the nozzle will ensure proper operation 
of the nozzle. Therefore, while we are maintaining the requirement to 
monitor liquid feed pressure, in the final rule, we are allowing a 
liquid feed pressure range to be established based on the 
manufacturer's recommendation or engineering analysis.
    Comment: Commenters requested the EPA revise the requirement to 
demonstrate compliance with the operating parameter limits for 
scrubbers used to control emissions from process vents and storage 
tanks in ethylene oxide service from an instantaneous basis to a daily 
average basis. Commenters explained that a daily average is consistent 
with the currently applicable requirements of 40 CFR part 63, subpart 
SS. One commenter stated that an instantaneous compliance demonstration 
with a measured value will likely lead to operators unnecessarily 
adjusting operating parameters in response to brief excursions due to 
changing process conditions. Another commenter explained that automated 
controls which maintain flow rate, temperature, pH, and other variables 
are typically ``feedback'' based or ``closed loop control,'' and even 
the best tuned controllers have some amount of response time. The 
commenter added that instantaneous compliance demonstrations will 
invariably lead to operators manually attempting to adjust control 
system variables which will likely lead to overshoot and potentially 
decreased control efficiency and concluded that the EPA must allow some 
amount of averaging to account for the inherent response time of 
control systems and deadtime of process response.
    One commenter added that a daily average aligns better with the 
process of establishing the parameter operating limits during a 
performance test, which typically consists of three 1-hour runs. 
Another commenter contended that the rule should at least allow for 3-
hour averages and stated this would be more consistent with other 40 
CFR part 63 MACT rules (such as the Hazardous Organic NESHAP (HON)) and 
with the process of establishing the parameter operating limits during 
a performance test (i.e., testing typically consists of three 1-hour 
runs).
    Response: The EPA is 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. We agree that instantaneous limits 
on operating parameters may cause some unintended consequences with 
control loops and that some degree of averaging is warranted.
    While we acknowledge that compliance with other operating 
parameters for MON sources is based on a daily average, per the 
requirements in 40 CFR part 63, subpart SS, we do not agree that this 
averaging basis is appropriate for operating parameters on control 
devices used for ethylene oxide process vents and storage tanks. 
Control devices used for ethylene oxide emissions operate differently 
than other control devices and are required to achieve better control 
than other control devices. In order to achieve 99.9-percent control 
from these devices, it is important to ensure that the ethylene oxide 
control is continuously occurring. These control devices tend to be 
used on batch processes, where the ethylene oxide emissions may 
fluctuate greatly with different steps in the process. Longer averaging 
times could mask issues with achieving the required control efficiency 
during brief periods of higher ethylene oxide loading to the control 
device (e.g., during tank loading events). In order to ensure 
continuous compliance with the control efficiency requirement, we are 
requiring compliance with the operating parameters be based on a 1-hour 
average in the final rule.
    Comment: Commenters interpreted the proposed language at 40 CFR 
63.2493(d)(4) to mean that (1) the discharge piping on PRDs in ethylene 
oxide service cannot be routed to the atmosphere and (2) any release 
event is an automatic violation of the MON rule. Commenters contended 
that the proposed rule seems to require that the PRD be directed to 
some form of emission control equipment, such as a flare. Commenters 
opposed requiring all PRDs in ethylene oxide service vent to a control 
device. Commenters contended the requirement would create safety 
concerns including the hydraulic limitations of the flare or other 
control device, backpressure limitations on the PRDs, and the 
incompatibility of

[[Page 49106]]

chemicals in vent streams in downstream controls. Commenters noted that 
ethylene oxide is a compound which contains oxygen and is highly 
reactive, extremely flammable, and can violently decompose with a 
significant release of heat in the absence of air, and ethylene oxide 
also tends to polymerize, which could result in plugging of the closed 
vent system or control device. The commenter concluded that existing 
closed vent systems and control devices require careful evaluation to 
determine if emissions from such events can be safely controlled.
    A commenter stated that because they are of limited duration and 
number, such events would not lower cancer risks, which are based on 
long term exposures. The commenter pointed out that the EPA makes no 
mention of PRDs when discussing ethylene oxide risk drivers.
    The commenter stated that the same technical limitations that apply 
to PRDs in general also apply to those in ethylene oxide service. 
Commenters supported requiring PRDs in ethylene oxide service to comply 
with the proposed PRD work practice at 40 CFR 63.2480(e). A commenter 
stated that other existing EPA regulations already require the owner/
operator to minimize or eliminate the potential for such releases, such 
as the EPA regulations at 40 CFR part 302 and 40 CFR part 355 have a 
10-pound reportable quantity for ethylene oxide if a release from any 
equipment occurs. The commenter added that if a release greater than 10 
pounds occurs, then the owner/operator must report it to the National 
Response Center, the State Emergency Response Commission (typically a 
state environmental agency), and the Local Emergency Planning Committee 
when the owner/operator has knowledge of such a release.
    A commenter added that a MON MCPU may not have a flare or may be 
located in an area of a larger site where there is not adequate land 
space for a flare.
    A commenter added that if a new flare or other emission control 
equipment is required, design and installation of a flare system or 
other emission control equipment within 2 years of the final date of 
this rule is not practical. Commenters stated that typically, it takes 
3 years to properly engineer the project, obtain capital authorization 
and funding, procure the equipment, and construct and start-up the 
equipment. Commenters noted that the EPA has not provided any 
background information in the preamble or in the rule docket that 
addresses costs or the feasibility of installing large flares or other 
air emission control equipment within the 2-year compliance period.
    Response: We are revising the proposed requirement that PRDs in 
ethylene oxide service must not vent directly to the atmosphere. 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. We are finalizing these requirements 
pursuant to CAA section 112(f)(2), on the basis for risks being 
unacceptable. Where we find risks are unacceptable, the EPA must 
determine the emissions standards necessary to reduce risk to an 
acceptable level. Because emissions of ethylene oxide from this source 
category result in unacceptable risks, we proposed and are finalizing 
requirements that would reduce risks to an acceptable level, including 
provisions that would make all PRD releases of ethylene oxide directly 
to the atmosphere a violation of the standard. We believe that there 
are very few PRDs in ethylene oxide service that vent to the 
atmosphere. Note that the proposed rule does not specify that PRDs must 
be controlled with flares; in fact, the detailed information we have 
indicate that most of these emission sources are controlled using 
scrubbers. Further, we reviewed emission release reports from the 
National Response Center for the 5-year period beginning in 2015 
through 2019 and identified only one reported release of ethylene oxide 
from an ethylene oxide production facility which is not part of the 
Miscellaneous Organic Chemical Manufacturing source category. Also, 
during the public comment period, commenters did not submit any 
specific information on the existence of, or lack of, ethylene oxide 
releases from PRDs in the Miscellaneous Organic Chemical Manufacturing 
source category. Therefore, we maintain that controlling PRDs in 
ethylene oxide service is possible, and in fact represents the majority 
of industry's practice in this source category.
4. What is the rationale for our final approach and final decisions for 
the risk review?
    As noted in our proposal, the EPA sets standards under CAA section 
112(f)(2) using ``a two-step standard-setting approach, with an 
analytical first step to determine an `acceptable risk' that considers 
all health information, including risk estimation uncertainty, and 
includes a presumptive benchmark on MIR of approximately 1-in-10 
thousand'' (84 FR 54278, October 9, 2019; see also 54 FR 38045, 
September 9, 1989). We weigh all health risk factors in our risk 
acceptability determination, including the cancer MIR, cancer 
incidence, the maximum cancer TOSHI, the maximum acute noncancer HQ, 
the extent of noncancer risks, the distribution of cancer and noncancer 
risks in the exposed population, multipathway risks, and the risk 
estimation uncertainties.
    Since proposal, our determinations regarding risk acceptability, 
ample margin of safety, or adverse environmental effects have not 
changed. However, after proposal, commenters provided updated 
information on their facilities, including specific information 
regarding sources in their facility that are subject to the MON, 
emissions from each emissions source, controls in use, and operating 
information. We updated the risk assessment for the two facilities 
that, at proposal, had a MIR greater than 100-in-1 million. The revised 
risk assessment (see document, Residual Risk Assessment for the 
Miscellaneous Organic Chemical Manufacturing Source Category in Support 
of the 2020 Risk and Technology Review Final Rule, which is available 
in the docket for this rulemaking) shows that, after application of 
controls finalized in this rulemaking, the MIR for the source category 
is 200-in-1 million.
    As discussed in section IV.A.3.b of this preamble, the 100-in-1 
million cancer risk is not a bright line indicating that risk is 
``acceptable''; rather, we consider this health metric in conjunction 
with a variety of health factors and their associated uncertainties to 
determine whether the risk is acceptable. We considered the number of 
people exposed to risks greater than 100-in-1 million (107 people, or 
0.0001 percent of the population living near a facility in the source 
category), the cancer incidence (0.09), and the number of people 
exposed to cancer risk levels greater than 1-in-1 million (1,400,000 
people, or 2 percent of the population living near a facility in the 
source category), which are consistent with other rules where risks 
above 100-in-1 million were found to be acceptable (see section 
IV.A.3.b of this preamble for more details). We also considered that no 
safe controls were identified to further reduce risks. Therefore, 
considering the uncertainties inherent in all risk assessments as 
discussed in the preamble to the proposed rule (i.e., the emissions 
dataset, dispersion modeling, exposure

[[Page 49107]]

estimates, and dose-response relationships) (see 84 FR 69219) and the 
EPA's use of the 2016 IRIS URE for ethylene oxide (which is developed 
to be health protective), and additional considerations discussed here 
and in more detail in section IV.A.3.b of this preamble, after 
application of the ethylene oxide-specific controls for process vents, 
storage tanks, and equipment leaks from co-proposed Control Option 1, 
we find that the risks are acceptable and that the final standards will 
achieve an ample margin of safety to protect human health.

B. Technology Review for the Miscellaneous Organic Chemical 
Manufacturing Source Category

1. What did we propose pursuant to CAA section 112(d)(6) for the 
Miscellaneous Organic Chemical Manufacturing source category?
    Based on our technology review for the Miscellaneous Organic 
Chemical Manufacturing source category, we proposed under CAA section 
112(d)(6) changes to the standards for equipment leaks and heat 
exchange systems, and we proposed no changed under CAA section 
112(d)(6) for process vents, storage tanks, transfer racks, and 
wastewater streams. We provide a summary of our findings, as proposed, 
in this section.
a. Equipment Leaks
    In our technology review for the Miscellaneous Organic Chemical 
Manufacturing source category, we identified developments in LDAR 
practices and processes for equipment leaks (excluding equipment in 
ethylene service). We identified four options for lowering the leak 
definition for certain process and component types and requiring 
periodic monitoring, and the options varied by leak definition level, 
process type (i.e., batch process v. continuous process), component 
type, and monitoring frequency. Refer to section IV.D.1 of the proposal 
preamble (84 FR 69182, December 17, 2019) for a summary of the four 
options. Based on our evaluation of the costs and emission reductions 
of each of the four options, we determined that the most cost-effective 
strategy was 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 and initial monitoring within 30 days after initial startup 
of the equipment, which we proposed pursuant to CAA section 112(d)(6) 
to further reduce HAP emissions from equipment leaks for MON equipment 
not in ethylene service.
    For a detailed discussion of the EPA's findings, refer to the 
memorandum, Clean Air Act Section 112(d)(6) Technology Review for 
Equipment Leaks Located in the Miscellaneous Organic Chemical 
Manufacturing Source Category, which is available in the docket for 
this rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-0003).
b. Heat Exchange Systems
    In our technology review for the Miscellaneous Organic Chemical 
Manufacturing source category, we identified one development in 
practices and processes for heat exchange systems, the use of the 
Modified El Paso Method \17\ for monitoring for leaks from heat 
exchange systems. We determined that this method is more effective in 
identifying leaks and measures a larger number of compounds than the 
methods previously required in the MON. After evaluating state and 
Federal regulations requiring the Modified El Paso Method, as well as 
emission data collected for the Ethylene Production RTR (refer to 
section II.D of the proposal preamble (84 FR 69182, December 17, 2019) 
and the Ethylene Production RTR rulemaking docket, Docket ID No. EPA-
HQ-OAR-2017-0357), we proposed pursuant to CAA section 112(d)(6) to 
require use of the Modified El Paso Method with a leak definition of 
6.2 ppmv of total strippable hydrocarbon concentration (as methane) in 
the stripping gas to further reduce HAP emissions from both new and 
existing heat exchange systems, as well as to disallow delay of repair 
of leaks if the measured concentration meets or exceeds 62 ppmv. Based 
on an evaluation of incremental HAP cost effectiveness to increase the 
monitoring frequency, we proposed no changes to the monitoring 
frequency previously required under the MON for monitoring for leaks 
from heat exchange systems, which continues to be monthly monitoring in 
the first 6 months following startup of a source and quarterly 
monitoring thereafter. We also proposed to require re-monitoring at the 
monitoring location where a leak is identified to ensure that any leaks 
found are fixed. Further, we proposed that none of these proposed 
requirements for heat exchange systems apply to heat exchange systems 
that have a maximum cooling water flow rate of 10 gpm or less. Refer to 
section IV.D.2 of the proposal preamble (84 FR 69182, December 17, 
2019) for a summary of our rationale for selecting the proposed leak 
method, leak definition, and limitation on delay of repairs, as well as 
our rationale for retaining the previous monitoring schedule.
---------------------------------------------------------------------------

    \17\ The Modified El Paso Method uses a dynamic or flow-through 
system for air stripping a sample of the water and analyzing the 
resultant off-gases for volatile organic compounds (VOC) using a 
common flame ionization detector (FID) analyzer. The method is 
described in detail in Appendix P of the TCEQ's Sampling Procedures 
Manual: The Air Stripping Method (Modified El Paso Method) for 
Determination of Volatile Organic Compound (VOC) Emissions from 
Water Sources. Appendix P is included in the docket for this 
rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-0024).
---------------------------------------------------------------------------

    For a detailed discussion of the EPA's findings, refer to the 
memorandum, Clean Air Act Section 112(d)(6) Technology Review for Heat 
Exchange Systems Located in the Miscellaneous Organic Chemical 
Manufacturing Source Category, which is available in the docket for 
this rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-0007).
c. Process Vents, Storage Tanks, Transfer Racks, and Wastewater Streams
    In our technology review of process vents, storage tanks, transfer 
racks, and wastewater streams for the Miscellaneous Organic Chemical 
Manufacturing source category, we identified no cost-effective 
developments in practices, processes, or control technologies for these 
emissions sources that would achieve a greater HAP emission reduction 
beyond the emission reduction already required by MON. Therefore, we 
proposed no revisions to the MON pursuant to CAA section 112(d)(6) for 
process vents, storage tanks, transfer racks, and wastewater streams. 
For a detailed discussion of the EPA's findings, refer to the 
memorandum, Clean Air Act Section 112(d)(6) Technology Review for 
Process Vents, Wastewater, Transfer Racks, and Storage Tanks Located in 
the Miscellaneous Organic Chemical Manufacturing Source Category, which 
is available in the docket for this rulemaking (see Docket Item No. 
EPA-HQ-OAR-2018-0746-0008). This analysis is also described in detail 
in section IV.B of the preamble to the proposal preamble (84 FR 69182, 
December 17, 2019).
2. How did the technology review change for the Miscellaneous Organic 
Chemical Manufacturing source category?
    We are finalizing the results of the technology review for the 
Miscellaneous Organic Chemical Manufacturing source category as 
proposed (84 FR 69182, December 17, 2019), with the following 
exceptions.

[[Page 49108]]

    For equipment leaks not in ethylene oxide service, based on 
comments received on the proposal, 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 are taking final action on the 
proposed requirement to monitor leaks from heat exchange systems using 
the Modified El Paso Method consistent with the December 17, 2019, RTR 
proposal. 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 gpm or less.
3. What key comments did we receive on the technology review, and what 
are our responses?
    This section provides comment and responses for the key comments 
received regarding our proposed revisions for equipment leaks; heat 
exchange systems; and process vents, transfer racks, storage tanks, and 
wastewater streams. Other comment summaries and the EPA's responses for 
additional issues raised regarding these activities, as well as issues 
raised regarding our proposed revisions, 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.
    For equipment leaks not in ethylene oxide service, we received 
comments on potential issues and problems associated with the proposed 
requirements for pumps in light liquid service (in an MCPU that has no 
continuous process vents and is part of an existing source) to meet a 
leak definition of 1,000 ppmv and requiring facilities to initially 
monitor for equipment leaks within 30 days after initial startup of the 
equipment. See section IV.B.3.a of this preamble for further details.
    For heat exchange systems, the EPA received additional information 
from commenters on costs necessary for control of these sources as well 
as comments on a number of technical clarifications and allowance of 
compliance with an alternative mass-based leak action level should the 
EPA finalize the requirements for heat exchange systems. See section 
IV.B.3.b of this preamble for further details.
    For process vents, transfer racks, equipment leaks, and wastewater 
streams, the comments were supportive of the determination that no 
cost-effective developments from the technology review were found. See 
section IV.B.3.c of this preamble for further details.
a. Equipment Leaks
    Comment: A commenter requested the EPA not finalize the lowering of 
the leak definition for batch light liquid pumps from 10,000 ppm to 
1,000 ppm because it inadvertently removes existing exemptions for all 
pumps. The commenter contended that instead of simply nullifying 40 CFR 
63.2480(b)(5), which sets the leak definition to 10,000 ppm for batch 
pumps, the language in 40 CFR 63.2480(b)(6) appears to apply to all 
pumps, not just those for batch processes. The commenter added that as 
a result, the leak definitions for pumps in specific service (i.e., 
polymerizing polymers and food/medical service) and the 2,000 ppm 
repair threshold in subparts H and UU will be overwritten. The 
commenter contended that the EPA has provided no analysis or 
justification for such a change. The commenter added that if the 
revision is intended to apply only to batch pumps, this results in 
continuation of different standards for batch and continuous pumps. The 
commenter suggested that to clarify the requirements and streamline 
compliance the EPA should apply the same standards to all pumps in 
light liquid service.
    Response: We agree with the commenter that the proposed requirement 
of a leak definition of 1,000 ppm for light liquid pumps at both batch 
and continuous processes directly in the MON rule inadvertently 
overrode facilities complying with the equipment leak requirements in 
subparts H and UU as the MON references both rules for leak 
definitions. The intention of the proposed requirement was to make the 
light liquid pump requirements for batch processes the same as the 
existing requirements for continuous processes and streamline the 
requirements by codifying them in the MON rule. The intention was not 
to remove the existing exemptions or repair requirements. We have 
revised the final rule to require light liquid pumps in batch and 
continuous processes that are not in ethylene oxide service to comply 
with the requirements in 40 CFR part 63, subpart H or UU, or 40 CFR 
part 65, subpart F, which is a leak definition of 1,000 ppmv, by 
removing the exemption for light liquid pump monitoring in 40 CFR 
63.2480(b)(5) and 40 CFR 63.2480(c)(5) and removing the proposed leak 
definition in the MON.
    Comment: Some commenters requested the EPA not finalize the 
proposed requirements at 40 CFR 63.2480(b)(7) and (c)(11) that specify 
initially monitoring leaks 30 days after initial startup of the 
equipment. The commenters contended this requirement adds a significant 
burden that the EPA did not consider, nor has the EPA provided any 
justification as to whether this requirement would provide any 
emissions reductions.
    One commenter contended that 40 CFR 63.2480(b)(7) and (c)(11) 
specify that ``each piece of equipment'' must be monitored initially 
for leaks within 30 days after initial startup of the equipment and 
that the term ``Equipment'' is already defined in the MON at 40 CFR 
63.2550. The commenter contended that this could be interpreted to 
require this 30-day monitoring requirement to apply to every single 
piece of equipment within the scope of the ``Equipment'' definition 
regardless of monitoring exemptions or the fact that some component 
types do not require routine monitoring. The commenter stated that 
equipment excluded from monitoring under the MON (e.g., equipment 
routed to control, fuel gas or a process; equipment in heavy liquid 
service; instrumentation systems; open-ended lines and valves; and 
connectors) should be excluded from this new requirement. The commenter 
also contended that pumps and agitators are already checked weekly and 
monthly and thus should be excluded from this new requirement and that, 
for clarity and simplicity, it would be simplest to limit these new 
requirements to gas and light liquid valves. The commenter also 
requested that the EPA clarify that ``replacement'' does not include 
reinstalling an item of equipment that has been removed for inspection 
or repair. The commenter provided an example of PRDs that are typically 
removed for bench testing and then replaced. The commenter continued 
that since the bench test confirms the PRD does not open until the set 
pressure is reached, there is no need to test it outside of the normal 
periodic schedule. The commenter also identified repaired equipment as 
already being required to re-monitor within 15 days and thus should 
also be

[[Page 49109]]

excluded from the 30-day requirement. Another commenter recommended 
that this initial monitoring requirement should also apply only to 
equipment that is subject to periodic monitoring with EPA Method 21 of 
appendix A-7 to 40 CFR part 60.
    Some commenters stated that the proposed requirement would require 
significant training of maintenance and operations staff and 
development and implementation of tracking systems to ensure no 
equipment component is replaced or added without conducting the 30-day 
monitoring. Commenters stated that this will place a significant burden 
and cost to an MCPU and that the EPA did not consider the burden 
associated with tagging, updating the LDAR program, and managing the 
component-by-component leak schedule this proposed requirement will 
impose, especially for equipment that is added or replaced frequently 
within an MCPU.
    Commenters contended some MON processes restrict additional 
personnel, such as LDAR personnel, in their operating areas for safety 
reasons; and some equipment is never safe to monitor while in service. 
The commenters added that safety restrictions may be in place for a 
period of time, which then reduces the number of days in the 30-day 
period for the initial monitoring. One commenter concluded that a 30-
day period is not long enough to organize the initial monitoring for 
these components or even components in less restricted areas.
    One commenter stated that the compliance date section in 40 CFR 
63.2445(g)(3) does not mention when the 30-day requirement in 40 CFR 
63.2480(b)(7) and (c)(11) becomes effective, so it appears that the 
language might be effective the date the final rule is published. The 
commenter recommended that the requirement in 40 CFR 63.2480(b)(7) and 
(c)(11) to initially monitor each piece of equipment for leaks within 
30 days after initial startup of equipment should be amended to 
reference the language in 40 CFR 63.162(g) of HON subpart H and 40 CFR 
65.3(d) of the Consolidated Federal Air Rule to determine the first 
monitoring period depending on how many days are left in the week, 
weeks remaining in the month, months remaining in the quarter, and 
quarters remaining in the year. Two commenters stated that if the EPA 
promulgates these requirements, the proposed applicability date should 
be changed from December 17, 2019, to 3 years after the date of 
publication of the final rule. One commenter stated that if the EPA 
promulgates these requirements, more time is needed, such as 3 months 
from the time components initially are in organic HAP service. The 
commenter contended that the EPA cannot impose requirements 
retroactively and that time is needed to develop the infrastructure to 
address this requirement.
    One commenter contended that this change is presented as a 
``clarification'' in the preamble discussion, but no such requirement 
was part of the negotiated rulemaking \18\ that established the part 63 
LDAR program, nor is such a requirement suggested in the existing 
language as shown by the EPA's need to propose new language to this 
rule to impose this requirement. The commenter claimed that this is a 
new requirement, not a clarification. The commenter added that as such, 
it must be justified under CAA section 112(d)(6). Commenters contended 
that nothing is presented in the MON record to show there is a problem 
with current (generally quarterly) periodic monitoring as specified in 
the existing 40 CFR part 63, subpart H or UU, or 40 CFR part 65, 
subpart F. One commenter said that the EPA appears to have recognized 
the challenges to implementing initial monitoring requirements 30 days 
after initial startup of equipment and cited the HON as it requires 
only new sources to initially monitor only valves in gas/vapor service 
and light liquid service quarterly. The commenter presumed that this 
provision was added to the HON for new sources because of the results 
of the MACT determination under the HON. The commenter concluded that 
the EPA had not conducted a MACT determination for this proposed 
provision under the MON, nor has it completed a cost-benefit or risk 
analysis necessary to add this requirement under this technology or 
risk review.
---------------------------------------------------------------------------

    \18\ Commenter provided the following reference: 57 FR 62617-
62619 (December 31, 1992).
---------------------------------------------------------------------------

    One commenter contended that by claiming this new requirement is a 
``clarification'' it could mistakenly be construed as applying to all 
part 63 and 65 LDAR programs. The commenter stated that proposing this 
change in the MON RTR rulemaking does not provide adequate notice and 
an opportunity for comment to most of the sources potentially impacted. 
The commenter recommended that the EPA should clarify that this is a 
new requirement and is only applicable to sources subject to the MON 
and that it is not a clarification of existing requirements in 40 CFR 
part 63, subpart H or UU, or in 40 CFR part 65, subpart F.
    Response: The EPA did not intend for the requirement to initially 
monitor components 30 days after initial startup of the equipment to 
apply as broadly as the commenters have interpreted. We intended for 
the requirement to only apply to new or replaced equipment regulated 
under the MON that must be periodically monitored with EPA Method 21. 
Similar requirements were promulgated in 40 CFR part 60, subparts VV 
and VVa. We agree with the commenters that the requirement to monitor 
equipment within 30 days of startup is not appropriate for equipment 
that are classified as unsafe-to-monitor or difficult-to-monitor due to 
their locations and safety concerns.
    In the final rule, we are clarifying at 40 CFR 63.2480(b)(7) and 
(c)(11) that monitoring leaks within 30 days after initial startup 
applies only to new or replaced equipment that is subject to Table 6 to 
40 CFR part 63, subpart FFFF, and is also subject to periodic 
monitoring with the EPA Method 21 of appendix A-7 to 40 CFR part 60. We 
are also clarifying that the requirement does not apply to equipment 
classified as unsafe-to-monitor or difficult-to-monitor equipment. 
Following the initial monitoring, the equipment may follow the periodic 
monitoring program applicable to each affected process unit. We are not 
changing the compliance date for this requirement in the final rule, 
and the requirement will be effective the date the final rule is 
published in the Federal Register. This requirement only applies to new 
and replaced components, and as such, we expect facilities are able to 
appropriately plan ahead for installation of new components.
    We disagree with commenters that a 112(d)(6) review is needed for 
this requirement. The requirement to conduct initial monitoring of 
equipment for leaks within 30 days of startup is a clarification to the 
compliance provisions of an existing work practice, not a new work 
practice. As discussed earlier, a similar change was made for 40 CFR 
part 60, subpart VV. As we stated in that rulemaking (72 FR 64862), the 
change is a clarification of the initial monitoring requirements. The 
clarification is intended to provide certainty to owners or operators 
on the timeframe in which this compliance activity must be conducted.
b. Heat Exchange Systems
    Comment: We received comments in support of and against the 
proposal to require use of the Modified El Paso Method for detecting 
and repairing leaks in heat exchange systems.
    One commenter supported the use of the Modified El Paso Method, and 
stated that in the Ethylene Production

[[Page 49110]]

rulemaking, the EPA found that at least 20 heat exchange systems (at 
eight facilities) are already required by TCEQ's highly reactive 
volatile organic compounds (HRVOC) rule to conduct continuous Modified 
El Paso Method monitoring.
    Some commenters opposed the proposed control requirements for heat 
exchange systems, stating the requirements were not cost effective when 
considering the actual costs to repair leaks. Some commenters said that 
the costs provided in Table 3 of the memorandum, Clean Air Act Section 
112(d)(6) Technology Review for Heat Exchange Systems Located in the 
Miscellaneous Organic Chemical Manufacturing Source Category for the 
Final Rule, significantly underestimate the true cost associated with 
leak repair at MON facilities. The commenters contended that the EPA 
has not taken into account that after identifying a leak, maintenance 
and operations personnel must develop a strategy and schedule to remove 
the leaking exchanger from service to conduct the repair. The commenter 
explained that this activity involves identifying and selecting options 
for bypassing the process stream from the leaking system, determining 
the amount of production turndown necessary while the exchanger is out 
of service, identifying and selecting the appropriate contract 
personnel, and scheduling the work so that it does not conflict with 
any other planned maintenance. The commenters said these steps alone 
require approximately 128 personnel hours. In addition to these costs, 
the commenters said that the EPA did not include costs for bypassing 
the leaking system to avoid a total shutdown, which may include renting 
and plumbing temporary heat exchangers. The commenters also said that 
the EPA did not include costs for the rental and installation of cranes 
and scaffolding for accessing the heat exchanger for repairs or costs 
for specialized contracted maintenance support to de-head the exchanger 
and perform the repair. The commenters contended that repair costs 
range from $200,000 to $400,000 per event, not considering lost profit 
due to turndown or shutdown of the production unit. Factoring in these 
additional costs and using the EPA's calculated HAP emissions 
reductions of 31 tons per year, the commenters said the revised cost 
effectiveness becomes $161,930 per ton of HAP. The commenters cited the 
NESHAP final RTR for Friction Materials Manufacturing Facilities (83 FR 
19511) where the EPA found a $3,700 per ton cost for a permanent total 
enclosure not cost effective, and the NESHAP proposed RTR for the 
Petroleum Refinery Sector (79 FR 36916) where the EPA found a $14,100 
per ton cost for lowering leak definitions not cost effective. The 
commenters stated that the EPA acknowledges in the preamble that 
emissions from heat exchange systems have no discernable impact on 
cancer risk for the modeled facilities and that additional controls for 
heat exchange systems are not necessary to provide an ample margin of 
safety.
    One commenter requested that the EPA reconsider the cost 
information submitted on heat exchanger leak repairs in the context of 
MON, independent of the prior decision made for the Ethylene Production 
RTR. The commenter said that the EPA's response to their similar 
comment for the Ethylene Production RTR, that heat exchange systems for 
ethylene production facilities were not cost effective, was not 
persuasive. The commenter said that the EPA must consider the entire 
cost of a heat exchanger repair for the additional/incremental repairs 
that will be required as a result of lower effective leak definitions 
and restrictions to the delay of repair provisions; for example, if the 
current rule requires 4 leaks to be repaired, and the revised rule 
requires 5 leaks to be repaired, the incremental cost is the entire 
repair cost for the 5th repair, not a subset of the repair costs, 
because the current rule would not require the 5th repair at all. In 
addition, the commenter said they provided a detailed account of 
several components of repair costs and the range of typical repair 
costs, yet the EPA did not consider this information in the final rule 
for the Ethylene Production RTR (signed on March 12, 2020). The 
commenter also objected to the EPA's response, to similar comments in 
the pre-publication of the final rule for the Ethylene Production RTR, 
that the ACC did not provide additional information for the agency to 
determine the amount of time additional leaks would have to be fixed 
under the revised heat exchange system standards. The commenter 
contended that EPA already had sufficient data. The commenter said the 
EPA based the leak distribution analysis in the technology review 
memorandum for heat exchange systems at ethylene production facilities 
on continuous monitoring data from 13 heat exchange systems at six 
facilities, and the EPA indicated that no leaks in the data were above 
the current rule threshold; thus, all leaks at the average leak 
distribution chosen for analysis that were above the new leak detection 
threshold would be considered ``incremental repairs.''
    One commenter contended that requiring the Modified El Paso method 
is not cost effective in all cases. The commenter stated that in 
certain cases, where soluble type HAP or VOC are the dominant organic 
species on the process side of the heat exchanger, the current leak 
detection method (i.e., cooling water sampling to detect leaks) is 
``adequate,'' and, therefore, the costs to change to using the El Paso 
method are ``not justified.'' The commenter explained that mandated 
conversion of their 56 heat exchanger systems (HES) to the Modified El 
Paso method would require installation of tubing and taps to set up 
sampling stations for the El Paso apparatus. The commenter added that 
where there is not room or access close by the HES, remote stations 
would have to be established. In order to take the measurements, the 
commenter stated that an LDAR Method 21 technician must accompany 
operators to the sampling locations and move the El Paso apparatus from 
location to location; otherwise, multiple El Paso sampling devices 
would have to be installed. The commenter contended that the costs 
associated with the proposed change are not justified when the current 
method is adequate to detect leaks.
    Response: The EPA is finalizing the proposed technology review 
revision under CAA section 112(d)(6) for heat exchange systems to use 
the Modified El Paso Method, with some minor technical clarifications 
that are discussed elsewhere in this section of this preamble and in 
the Summary of Public Comments and Responses for the Risk and 
Technology Review for the Miscellaneous Organic Chemical Manufacturing 
Source Category, available in the docket for this rulemaking. However, 
we disagree with commenters who said these proposed revisions are not 
cost effective. We believe that the developments we identified for heat 
exchange systems at MON sources are cost effective. We note that the 
existing MACT standards that were finalized in 2003 contain LDAR 
provisions; therefore, many of the costs mentioned by commenters (i.e., 
planning, bypassing, various equipment rental/purchase costs, and costs 
for scaffolding) are associated with repair costs that would have 
already been incurred under the existing MACT standards. Also, many of 
the items associated with cost that are listed by the commenters are 
not required by the rule, and the commenters did not provide sufficient 
information

[[Page 49111]]

demonstrating why these costs represent an average heat exchange system 
at a MCPU. For example, facilities may have additional heat exchange 
system capacity available to them at their facility and may opt to use 
this capacity to repair the leak, at no additional expense, yet this 
was not considered by commenters.
    Furthermore, because commenters did not provide information 
sufficient for us to evaluate the percentage of time additional leaks 
would have to be fixed under the proposed heat exchange system 
standards compared to the original MACT standards, we continue to 
believe that the majority, if not all, of the repair costs cited by 
commenters would have been accounted for and incurred as a result of 
the original MACT standards and that simply plugging a leaking heat 
exchanger would more likely represent the average cost additionally 
incurred by MON sources as a result of this technology review 
development. In addition, we stated in the proposed rule that we 
considered a heat exchanger that was leaking to the extent that it 
needed to be replaced to be effectively at the end of its useful life, 
so the cost of replacing the heat exchanger would be an operational 
cost that would be incurred by the facility as a result of routine 
maintenance and equipment replacement and not attributable to the work 
practice standard.
    Thus, given all of this information, we continue to believe that 
the only costs that would be additionally incurred by the proposed heat 
exchange system standards would be costs associated with the difference 
between doing leak sampling using water sampling methods and leak 
sampling using the Modified El Paso Method as well as with costs 
associated with combined operator and maintenance labor to find and 
repair a leak by plugging it. We also maintain that for almost all MON 
facilities,\19\ the use of the Modified El Paso method is much more 
sensitive in terms of being able to identify leaks of organic HAP 
compared to water sampling methods, and monitoring for a single 
surrogate parameter of organic HAP such as total strippable hydrocarbon 
can be easily accomplished with a single measurement using a common 
flame ionization detector (FID).
---------------------------------------------------------------------------

    \19\ We are aware of only one MON facility where it is possible 
that the only HAP that has potential to be present in a heat 
exchange system is methanol and/or ethylene glycol. In this specific 
case, the Modified El Paso method may not be as sensitive as water 
sampling methods; and the owners or operators of this facility could 
submit more detailed information regarding their specific situation 
to the EPA and request an alternative test method or an alternative 
monitoring method pursuant to 40 CFR 63.7(f) and 40 CFR 63.8(f), 
respectively. Under 40 CFR 63.7(f) and 40 CFR 63.8(f) (in subpart 
A--General Provisions), a source may apply to the EPA for permission 
to use alternative test methods or alternative monitoring 
requirements in place of any required testing methods, performance 
specifications, or procedures in the final rule or any amendments.
---------------------------------------------------------------------------

    We note that, based on data collected for ethylene sources, we 
anticipate that the subsequent leak distribution would reasonably 
represent implementation of the Modified El Paso Method because it is 
the average leak distribution of 13 heat exchange systems at 6 ethylene 
facilities using this method. However, given that the initial leak 
distribution is based on a heat exchange system employing continuous 
Modified El Paso monitoring, it is likely that emission reduction 
estimates are understated given that the average MON facility does not 
have such readily available information on leaks and would only acquire 
such information on a quarterly basis using considerably higher leak 
sensitive test methods. In other words, and as described in more detail 
in our technology review memorandum for heat exchange systems (see 
Clean Air Act Section 112(d)(6) Technology Review for Heat Exchange 
Systems Located in the Miscellaneous Organic Chemical Manufacturing 
Source Category For the Final Rule, which is available in the docket 
for this rulemaking), the initial leak frequency distribution would 
likely show considerably higher percentages of larger leaks due to the 
sensitivity of the current water sampling method requirements in the 
rule and due to the fact that the dataset was developed from facilities 
employing continuous monitoring as opposed to less frequent (e.g., 
quarterly or monthly) monitoring. However, this was the best available 
data available to the agency, and so we used these conservative 
estimates. Based on our analysis, we find that the revised standards we 
proposed for heat exchange systems are cost effective at $8,530/ton of 
HAP without consideration of product recovery and the requirement has 
the potential to lead to a cost savings with product recovery. 
Therefore, we are finalizing the revisions for heat exchange systems 
that we proposed under the technology review with some minor technical 
clarifications that are discussed elsewhere in this document.
    We also note, with respect to other rules where we have determined 
control options to not be cost effective at varying levels of cost 
effectiveness, that other compelling factors in those rulemaking 
records likely led the EPA to those determinations and that each 
rulemaking record is unique and should be judged based on its own 
merits. With respect to the two proposed rules commenters cite (i.e., 
friction materials RTR and petroleum refinery RTR) where the EPA 
determined certain controls to not be cost effective, the EPA considers 
a number of rule-specific factors when determining what is, and what is 
not, cost effective. Regardless, and as stated above, we believe that 
the developments we identified for heat exchange systems at MON sources 
are cost effective, and we are finalizing these revisions under our CAA 
section 112(d)(6) authority.
    Comment: Two commenters recommended the EPA revise the heat 
exchange system requirements to include an alternative mass-based leak 
definition because it would reduce the overall costs of the final rule. 
The commenters argued that by only defining a leak on a concentration 
basis, smaller facilities with lower heat exchange system recirculation 
rates would be forced to identify and fix leaks with a much lower 
potential HAP emissions rate than facilities with larger recirculation 
systems. The commenters provided the EPA with survey results showing 
that 69 heat exchange systems subject to the MON rule have 
recirculation flowrates between 200 gpm and 80,000 gpm, except for four 
systems that have a flowrate greater than 80,000 gpm and that the 
average cooling water flow rate is 43,500 gpm. Based on this 
information, the commenters suggested the EPA establish an alternative 
leak action level of 1.6 pounds per hour of total strippable 
hydrocarbon and a delay of repair action level of 16 pounds per hour of 
total strippable hydrocarbon for systems with a recirculation flowrate 
less than or equal to 40,000 gpm. Another commenter said that the EPA 
must reduce the leak definition and aim to achieve zero leaks. The 
commenter also supported the use of the Modified El Paso Method, 
pointing out that in the Ethylene Production RTR, the EPA found that at 
least 20 heat exchange systems (at eight facilities) are already 
required by TCEQ's HRVOC rule to conduct continuous Modified El Paso 
Method monitoring.
    Response: We agree with commenters that an alternative mass-based 
leak action level is warranted (in lieu of a concentration-based leak 
action level) and that, by not finalizing such an alternative, smaller 
heat exchange systems with low recirculation rates would be 
disproportionally affected and forced to repair leaks with a much lower 
potential HAP emissions rate than facilities with larger recirculation 
rate systems. As commenters allude to, the goal of this alternative is 
to avoid

[[Page 49112]]

disproportionally impacting small heat exchange systems with low 
emissions potential. To that end and given that this is a technology 
review under CAA section 112(d)(6), consideration of where it is cost 
effective to repair a leaking heat exchange system is a consideration 
for this alternative mass-based leak action level. In the technology 
review memorandum, Clean Air Act Section 112(d)(6) Technology Review 
for Heat Exchange Systems Located in the Miscellaneous Organic Chemical 
Manufacturing Source Category For the Final Rule, available in the 
docket for this rulemaking, we determined that the nationwide impacts 
for HAP cost effectiveness (without consideration of product recovery) 
at $8,530/ton of HAP would be the HAP cost effectiveness for an average 
heat exchange system in the source category that has a recirculation 
rate of approximately 14,000 gpm. We also generally consider technology 
review developments to be near the upper end of acceptable cost 
effectiveness for organic HAP if the cost effectiveness is 
approximately $10,000/ton (or approximately 1.2 times higher than the 
cost effectiveness estimated for the average heat exchange system at 
MON sources). Since the recirculation rate directly correlates to mass 
emissions potential at the same leak concentration, the mass emissions 
for a heat exchange system with recirculation rate of 10,000 gpm or 
less (rounded to one significant figure) would be at least 1.2 times 
smaller compared to a 14,000 gpm recirculation rate system, and the 
annual costs to find and repair leaks would not change. As such, we 
determined that heat exchange systems with a recirculation rate of 
10,000 gpm or less would be less cost effective to monitor and repair 
because the HAP cost effectiveness would be approximately $10,000/ton 
of HAP or more. Therefore, to alleviate the concern about 
disproportionally impacting small heat exchange systems with low HAP 
emissions potential, and to ensure our technology review developments 
are cost effective for all heat exchange systems in the source 
category, we are finalizing an alternative total hydrocarbon mass-based 
emissions rate leak action level (as methane) of 0.18 kilograms per 
hour (0.4 pounds per hour) for heat exchange systems in the 
Miscellaneous Organic Chemical Manufacturing source category that have 
a recirculation rate of 10,000 gpm or less. We also agree that for 
consistency, and to not disproportionately impact small heat exchange 
systems, an alternative mass-based leak action level of 1.8 kilograms 
per hour (4.0 pounds per hour) for delay of repair for heat exchange 
systems with a recirculation rate of 10,000 gpm or less is warranted.
c. Process Vents, Storage Tanks, Transfer Racks, and Wastewater Streams
    Comment: Commenters supported the EPA's conclusion under the 
technology review that there are no cost-effective technology 
developments for process vents, storage tanks, transfer racks, and 
wastewater streams.
    Response: We acknowledge the commenters' support for the EPA's 
technology review conclusions.
4. What is the rationale for our final approach for the technology 
review?
    Our technology review focused on the identification and evaluation 
of developments in practices, processes, and control technologies that 
have occurred since the MON standards were originally promulgated on 
November 10, 2003 (68 FR 63852), and further amended on July 1, 2005 
(70 FR 38562), and July 14, 2006 (71 FR 40316). Specifically, we 
focused our technology review on all existing MACT standards for the 
various emission sources in the Miscellaneous Organic Chemical 
Manufacturing source category, including, storage vessels, process 
vents, transfer racks, equipment leaks, wastewater streams, and heat 
exchange systems. In the proposal, we identified cost-effective 
developments only for equipment leaks and heat exchange systems, and we 
proposed to revise the standards for these two emissions sources under 
the technology review. We did not identify developments in practices, 
processes, or control technologies for process vents, transfer racks, 
storage tanks, and wastewater streams. Further information regarding 
the technology review can be found in the proposed rule (84 FR 69182, 
December 17, 2019) and in the supporting materials in the rulemaking 
docket at Docket ID No. EPA-HQ-OAR-2017-0357.
    During the public comment period, we received several comments on 
our proposed determinations for the technology review. The comments and 
our specific responses and rationale for our final decisions can be 
found in section IV.B.3 of this preamble and in the document, Summary 
of Public Comments and Responses for the Risk and Technology Review for 
Miscellaneous Organic Chemical Manufacturing, available in the docket 
for this rulemaking. No information presented by commenters has led us 
to change our proposed determination under CAA section 112(d)(6) for 
process vents, transfer racks, storage tanks, and wastewater streams, 
and we are finalizing our determination that no changes to these 
standards are warranted. However, substantive information was submitted 
by commenters on proposed revisions for equipment leaks. Based on these 
comments, we are finalizing revisions for equipment leaks and making 
some technical clarifications to clarify 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 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. In addition, 
substantive information was also submitted by commenters on proposed 
revisions for heat exchange systems, and based on this information, we 
are finalizing revisions to require the Modified El Paso Method for 
heat exchange systems. We are also making some technical clarifications 
to allow compliance with the Modified El Paso Method using an 
alternative mass-based leak action level instead of a concentration-
based leak action level for small heat exchange systems with a 
recirculation rate of 10,000 gpm or less.

C. Amendments Pursuant to CAA Section 112(d)(2) and (3) and 112(h) for 
the Miscellaneous Organic Chemical Manufacturing Source Category

1. What did we propose pursuant to CAA section 112(d)(2) and (3) and 
112(h) for The Miscellaneous Organic Chemical Manufacturing source 
category?
    Under CAA sections 112(d)(2) and (3) we proposed to amend the 
operating and monitoring requirements for a subset of flares in the 
Miscellaneous Organic Chemical Manufacturing source category. We 
proposed that the subset of flares include flares in the Miscellaneous 
Organic Chemical Manufacturing source category that either (1) control 
ethylene oxide emissions, (2) control emissions from processes that 
produce olefins, or (3) control emissions from processes that produce 
polyolefins. In our proposal, we also proposed that flares controlling 
propane dehydrogenation (PDH) processes be included in the specified 
subset since the PDH process produces olefins such as propylene. We 
also proposed at 40 CFR 63.2535(m) to clarify that owners or operators 
of flares that are not considered to be in the specified subset but are 
subject to the

[[Page 49113]]

flare provisions of 40 CFR 60.18 or 63.11 may elect to comply with the 
new proposed flare standards in lieu of the provisions of 40 CFR 60.18 
or 63.11.
    We proposed at 40 CFR 63.2450(e)(5) to directly apply the petroleum 
refinery flare rule requirements in 40 CFR part 63, subpart CC, to the 
flares in the specified subset with clarifications, including, but not 
limited to, specifying that several definitions in 40 CFR part 63, 
subpart CC, that apply to petroleum refinery flares also apply to the 
flares in the specified subset, adding a definition and requirements 
for pressure-assisted multi-point flares, and specifying additional 
requirements when a gas chromatograph or mass spectrometer is used for 
compositional analysis. Specifically, we proposed to retain the General 
Provisions requirements of 40 CFR 63.11(b) and 40 CFR 60.18(b) such 
that flares in the specified subset operate pilot flame systems 
continuously and that these flares operate with no visible emissions 
(except for periods not to exceed a total of 5 minutes during any 2 
consecutive hours) when the flare vent gas flow rate is below the 
smokeless capacity of the flare. We also proposed to consolidate 
measures related to flare tip velocity and new operational and 
monitoring requirements related to the combustion zone gas for flares 
in the specific subset. Further, in keeping with the elimination of the 
SSM exemption, we proposed a work practice standard related to the 
visible emissions and velocity limits during periods when a flare in 
the specified subset is operated above its smokeless capacity (e.g., 
periods of emergency flaring). We proposed eliminating the cross-
references to the General Provisions and instead specifying all 
operational and monitoring requirements that are intended to apply to 
the flares in the specified subset in the MACT standards.
    In addition, we proposed provisions and clarifications 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, consistent with Sierra Club v. EPA 551 F. 3d 1019 
(D.C. Cir. 2008). For PRD releases, we proposed definitions at 40 CFR 
63.2550 of ``pressure release,'' ``pressure relief device,'' and 
``relief valve'' and under CAA section 112(h) we proposed a work 
practice standard for PRDs at 40 CFR 63.2480(e)(3), (6), and (7) that 
consists of using at least three prevention measures and performing 
root cause analysis and corrective action in the event that a PRD does 
release emissions directly to the atmosphere. (Examples of prevention 
measures include flow indicators, level indicators, temperature 
indicators, pressure indicators, routine inspection and maintenance 
programs or operator training, inherently safer designs or safety 
instrumentation systems, deluge systems, and staged relief systems 
where the initial PRD discharges to a control system.) We proposed that 
PRDs in ethylene oxide service may not vent directly to atmosphere. We 
also proposed to require that sources monitor PRDs that vent to 
atmosphere using a system that is capable of identifying and recording 
the time and duration of each pressure release and of notifying 
operators that a pressure release has occurred. We proposed at 40 CFR 
63.2480(e)(4) that PRDs that vent through a closed vent system to a 
control device or to a process, fuel gas system, or drain system must 
meet minimum requirements for the applicable control system. In 
addition, we proposed at 40 CFR 63.2480(e)(5) that the following types 
of PRDs would not be subject to the work practice standard for PRDs 
that vent to the atmosphere: (1) PRDs with a design release pressure of 
less than 2.5 pounds per square inch gauge (psig); (2) PRDs in heavy 
liquid service; (3) PRDs that are designed solely to release due to 
liquid thermal expansion; and (4) pilot-operated and balanced bellows 
PRDs if the primary release valve associated with the PRD is vented 
through a control system. Finally, we proposed at 40 CFR 63.2480(e)(8) 
to require future installation and operation of non-flowing pilot-
operated PRDs at all affected sources.
    For bypass lines on closed vent systems, we proposed at 40 CFR 
63.2450(e)(6) that an owner or operator may not bypass the air 
pollution control device (APCD) at any time, and if a bypass is used, 
then the owner or operator must estimate and report the quantity of 
organic HAP released. We proposed and are taking final action on this 
revision because bypassing an APCD could result in a large release of 
regulated organic HAP to the atmosphere (the removal efficiency 
required by the MON ranges from 95 to 99.9 percent, depending on the 
type of emission source). The MON requirements we are finalizing thus 
provide the Agency with the information necessary to evaluate these 
incidents and determine whether enforcement action is necessary to 
address such releases to ensure they do not recur. We are also taking 
final action to allow the use of a cap, blind flange, plug, or second 
valve on an open-ended valve or line to prevent a bypass. For these 
reasons, we maintain that the MON as revised is consistent with Sierra 
Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), because the rule requires 
compliance with emission standards at all times as required by CAA 
section 112(d) and because the rule includes sufficient monitoring, 
recordkeeping and reporting requirements to allow the EPA to evaluate 
and address any unauthorized releases of HAP emissions.
    For maintenance activities, we proposed a work practice standard at 
40 CFR 63.2455(d)(1) requiring that, prior to opening process equipment 
to the atmosphere, the equipment must either (1) Be drained and purged 
to a closed system so that the hydrocarbon content is less than or 
equal to 10 percent of the LEL; (2) be opened and vented to the 
atmosphere only if the 10-percent LEL cannot be demonstrated and the 
pressure is less than or equal to 5 psig, provided there is no active 
purging of the equipment to the atmosphere until the LEL criterion is 
met; (3) be opened when there is less than 50 lbs of VOC that may be 
emitted to the atmosphere; or (4) for installing or removing an 
equipment blind, depressurize the equipment to 2 psig or less and 
maintain pressure of the equipment where purge gas enters the equipment 
at or below 2 psig during the blind flange installation, provided none 
of the other proposed work practice standards can be met. For cases 
where an emission source is required to be controlled in the MACT 
standards but is routed to a fuel gas system, we proposed that any 
flare receiving gases from that fuel gas system derived from an MCPU 
that has processes and/or equipment in ethylene oxide service or that 
produces olefins or polyolefins, and utilizing fuel gas whereby the 
majority (i.e., 50 percent or more) of the fuel gas in the fuel gas 
system is derived from an MCPU, comply with the proposed flare 
operating and monitoring requirements.
    More information concerning our proposed requirements under CAA 
section 112(d)(2) and (3) and 112(h) can be found in section IV.A of 
the proposal preamble (84 FR 69182, December 17, 2019).
2. How did the revisions pursuant to CAA section 112(d)(2) and (3) and 
112(h) change since proposal?
    The EPA is finalizing the revisions to the monitoring and 
operational requirements for flares, as proposed, except that we are 
not finalizing the work practice standard for velocity exceedances for 
flares operating above

[[Page 49114]]

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'' include only those MCPUs that manufacture ethylene, 
propylene, polyethylene, and/or polypropylene as a product; by-products 
and impurities as defined in 40 CFR 63.101, as well as wastes and trace 
contaminants, are not considered products.
    Also, we are adding a separate degassing standard in the final rule 
at 40 CFR 63.2470(f) for storage vessels subject to control 
requirements based on comments that owners or operators have 
historically considered degassing emissions from shutdown of storage 
vessels to be covered by their SSM plans per 40 CFR 63.63.2525(j) and 
relied on the language in 40 CFR 63.6(e)(1) and 40 CFR 63.2450(a)(1) 
that back-up control devices are not required. The standard requires 
owners or operators to control degassing emissions for floating roof 
and fixed roof storage vessels until the vapor space concentration is 
less than 10 percent of the LEL. Storage vessels may be vented to the 
atmosphere once the storage vessel degassing concentration threshold is 
met (i.e., 10-percent LEL) and all standing liquid has been removed 
from the vessel to the extent practical.
3. What key comments did we receive on the proposal revisions pursuant 
to CAA section 112(d)(2) and (3) and 112(h), and what are our 
responses?
    This section provides comment and responses for the key comments 
received regarding our proposed revisions for flares and clarifications 
for periods of SSM, including PRD releases and storage vessel emptying 
and degassing. Other comment summaries and the EPA's responses for 
additional issues raised regarding these activities, as well as issues 
raised regarding our proposed revisions for bypass lines on closed vent 
systems, maintenance activities, and certain gaseous streams routed to 
a fuel gas system, 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.
a. Flares
    Comment: We received comments in support of our proposal to 
establish similar requirements for flares (controlling ethylene oxide 
or emissions from processes that produce olefins and/or polyolefins) 
used in the Miscellaneous Organic Chemical Manufacturing source 
category as the flare requirements established in the 2015 Petroleum 
Refinery NESHAP, including the incorporation of the net heating value 
of the combustion zone gas (NHVcz) calculation and limits. One 
commenter said they supported the proposed strengthened operational and 
monitoring requirements because of the toxic nature of ethylene oxide 
and the photochemical reactivity of the olefins and polyolefins 
emissions.
    Another commenter cited various enforcement cases where the EPA 
found flare efficiency problems and applied flare operational and 
monitoring improvements to chemical plants. The commenter said that 
because MON sources do not currently have separate flare management 
plan requirements (as refineries do under CAA section 111 NSPS 
standards), it is particularly important and necessary for the EPA to 
update the flare requirements in this rule to assure that flares are 
working correctly to reduce HAP emissions. Also, the commenter 
reiterated the EPA's determination that measuring the net heating value 
of the flare gas, as it enters the flares, is insufficient to determine 
combustibility because facilities add steam and other gases not 
accounted for and that flare performance data shows that the net 
heating value of vent gas in the combustion zone must reach at least 
270 British thermal units per standard cubic foot (Btu/scf). Some 
commenters also supported the EPA's proposal ``that owners or operators 
may use a corrected heat content of 1,212 Btu/scf for hydrogen, instead 
of 274 Btu/scf, to demonstrate compliance with the NHVcz operating 
limit,'' because the data show that the control efficiency of a flare 
drops off significantly below this level. However, the commenters also 
suggested other improvements to the proposed flared revisions. The 
commenters recommended that the EPA also consider the following 
measures to help assure compliance with 98-percent destruction 
efficiency and said that these measures should be evaluated under CAA 
section 112(d)(6).
     Revise the standards to account for ``developments'' that 
improve emissions controls by eliminating or drastically reducing 
routine flaring, such as augmented flare capacity;
     The HAP emission rates from flares during malfunctions 
when process gases are routed to flares from process equipment should 
not be less stringent than the emission limits that apply to such units 
during normal operations.
     Set further limits on routine flaring that comply with CAA 
section 112(d)(2) and (3), and 112(f).
     Require continuous video monitoring and recording for 
flares equipped with video monitoring and flares that vent more than 1 
million scf per day.\20\
---------------------------------------------------------------------------

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

     Set limits on flaring that require flare gas recovery and 
other steps to reduce regular and routine flaring.
    Response: Except for minor clarifications discussed in the response 
to comment document for this rulemaking, the EPA is finalizing the 
flare operational and monitoring requirements at 40 CFR 63.2450(e)(5), 
as proposed, as supported by several commenters. We disagree with one 
commenter's request that we mandate additional measures to ensure 98-
percent flare destruction efficiency on top of those being finalized in 
this action under our CAA section 112(d)(2) and (3) authority. Flares 
are one of many APCDs that owners or operators of MCPUs can use to 
control HAP emissions from the Miscellaneous Organic Chemical 
Manufacturing source category and are not specific affected emission 
sources in the Miscellaneous Organic Chemical Manufacturing source 
category; thus, the flare requirements we are finalizing are already 
designed to ensure flares meet a minimum destruction efficiency of 98 
percent, consistent with the MACT control requirements.
    We disagree with commenters that we should impose the additional 
measures for flares under our CAA section 112(d)(6) authority because 
the revisions to the flare requirements are associated with compliance 
with the MACT standards established pursuant to CAA sections 112(d)(2) 
and (3). The rulemaking record contains the analyses on options we 
analyzed for our technology review, and owners or operators of MCPUs 
can chose from a variety of APCDs to demonstrate

[[Page 49115]]

compliance with the underlying MACT standards. Notably the commenter 
does not recommend similar actions to minimize or eliminate the use of 
thermal oxidizers, carbon absorbers, or other control devices that may 
be employed to control HAP emissions from the affected emission sources 
at an MCPU. Eliminating the routine use of flares as an acceptable APCD 
would only increase the use of these other types of APCD (at 
potentially significant cost) without any net emissions reductions from 
the MCPU (provided that the flare is meeting the required control 
efficiency). In addition, flare gas recovery has not been demonstrated 
at MCPU in the Miscellaneous Organic Chemical Manufacturing source 
category, and commenters did not provide sufficient information about 
requiring use of such systems specific to this source category.
    We disagree with the commenter's specific request to require 
continuous video monitoring and recording for flares equipped with 
video monitoring and flares that vent more than 1 MMscf/day. We are not 
removing the requirement to conduct EPA Method 22 monitoring because it 
has always been required for flares; however, because EPA Method 22 
does not allow the use of a video camera, we have provided for the use 
of video camera surveillance monitoring in the final rule as an 
alternative to EPA Method 22 monitoring. Observation via the video 
camera feed can be conducted readily throughout the day and will allow 
the operators of the flare to watch for visible emissions at the same 
time they are adjusting the flare operations. We note that in order for 
an owner or operator to be able to use the video camera surveillance 
monitoring option, the owner or operator must continuously record (at 
least one frame every 15 seconds with time and date stamps) images of 
the flare flame at a reasonable distance above the flare flame and at 
an angle suitable for visual emissions observations. The owner or 
operator must also provide real-time video surveillance camera output 
to the control room or other continuously manned location where the 
camera images may be viewed at any time.
    Lastly, with respect to consent decrees cited by the commenter, we 
note that the requirements in consent decrees are negotiated 
settlements and are not based on any analysis required in CAA section 
112 and do not factor in nationwide impacts specific to a source 
category of concern, which in this case is the Miscellaneous Organic 
Chemical Manufacturing source category.
    Comment: Commenters requested the EPA clarify in 40 CFR 
63.2450(e)(5) that the requirements only apply to (1) flares 
controlling emissions from sources in ethylene oxide service as defined 
in 40 CFR 63.2550 and (2) flares used as an APCD to comply with the 
emission limits and work practice standards in Tables 1, 2, 4, and 5 to 
40 CFR part 63, subpart FFFF, for emission sources located at MCPUs 
that produce olefins and/or polyolefins. A commenter said that the 
introductory language in 40 CFR 63.2450(e)(5) is ambiguous and appears 
to indicate that a flare that controls any amount of ethylene oxide or 
any amount of other HAP from olefins or polyolefins production 
processes would be subject to the proposed requirements. In addition, 
the commenter requested that the EPA limit the applicability of the 
revised provisions to those MCPUs producing lighter olefins and 
polyolefins and that heavy olefin (e.g., hexene) and heavy polyolefin 
(e.g., polybutene) production should be excluded because heavier 
materials used in such processes have much less potential to be flared. 
The commenter requested that the EPA define the phrase ``MCPUs that 
produce olefins or polyolefins'' and said that MCPUs may generate 
olefins or polyolefins as a by-product or impurity and these small 
amounts of materials do not justify the compliance costs associated 
with meeting the new flare requirements. The commenter recommended the 
EPA adopt definitions similar to those for ``Product, By-product,'' and 
``Impurity'' found in the HON (i.e., 40 CFR 63.101).
    Other commenters said the EPA must apply the proposed flare 
improvements to all MON flares, not just the subset that controls 
ethylene oxide and emissions from olefin/polyolefin processes. One 
commenter said that the refinery flare requirements, as proposed, will 
only apply to 16 of 145 flares in the source category and reiterated 
that this is less than 10 percent of the flares in the Miscellaneous 
Organic Chemical Manufacturing source category. The commenter said the 
EPA did not sufficiently explain why the flare improvements should not 
be applied to all MON flares.
    Response: First, as a general matter, the Miscellaneous Organic 
Chemical Manufacturing source category broadly encompasses a wide 
variety of chemical production processes not covered elsewhere under 
other 40 CFR part 63 NESHAP and, as such, is a ``catch all'' for a wide 
variety of processes producing various types of chemical products. The 
primary goal of applying the new suite of flare requirements to a 
certain flare subset is two-fold: (1) To ensure continuous compliance 
with the MON MACT standards at all times for the largest flare systems 
in the source category where the Agency has compelling data that show 
that the flare types and vent gases being controlled (e.g., olefinic 
vent gases that contain ethylene and/or propylene) could have 
deteriorated flare performance issues, and (2) to ensure continuous 
compliance with the MON MACT standards at all times for flare systems 
controlling ethylene oxide, the cancer risk driving HAP for the source 
category. In particular, when the EPA reviewed available data about 
flare APCDs being used in the Miscellaneous Organic Chemical 
Manufacturing source category and the potential for deteriorated 
combustion efficiencies to occur during certain modes of operation 
(e.g., over-assisting steam-assisted flares), we determined that vent 
gases consisting of olefinic material can be over-assisted and that 
flare performance for these types of MCPUs could be diminished (i.e., 
consistent with the passive fourier transfer infrared spectrometry 
(PFTIR) test data reviewed and that formed the basis of the Petroleum 
Refinery requirements at 40 CFR part 63, subpart CC, we cross-reference 
in this final rule for the MON). In addition, the EPA has recently 
reviewed and approved a number of AMEL requests from MON facilities 
that produce olefins/polyolefins, and this subset of facilities in the 
Miscellaneous Organic Chemical Manufacturing source category comprises 
the largest flare systems in the source category, making issues of 
deteriorated flare performance of particular concern. With respect to 
flares controlling emissions of ethylene oxide, the EPA also wanted to 
ensure that these flare systems would be subject to more stringent 
compliance assurance requirements to ensure over-assisting does not 
occur for these flare types given risks associated with ethylene oxide 
in the source category. Thus, these two criteria were chosen to 
constitute the basis of our flare subset given both the data before us 
and the concern for potential risk issues if deteriorated flare 
performance were to occur for flares controlling emissions of ethylene 
oxide from the source category. Given that we do not have sufficient 
data about the types of flares and flare vent gases that the other 
various MCPUs outside the flare subset would be controlling, we are 
unable to determine whether the new suite of flare requirements would 
be necessary or warranted as the existing suite of flare requirements 
may be sufficient for these

[[Page 49116]]

other flares. Commenters did not provide the Agency with any 
information about this, including test data, flare vent gas 
characteristics, and specific instances of deteriorated flare 
performance for flares outside the flare subset, thus we disagree that 
we should broadly apply these new flare requirements to all flares in 
the source category without this information. We note, however, that we 
proposed and are finalizing as an alternative that owners or operators 
of flares outside the flare subset may opt to comply with the new suite 
of flare requirements should they choose.
    With respect to comments requesting the EPA to clarify what was 
meant when referring to production of olefins and/or polyolefins, we 
are adding a definition for ``MCPUs that produce olefins or 
polyolefins'' for purposes of the new suite of flare requirements only 
and clarifying that these MCPUs include production of ethylene, 
propylene, polyethylene, and polypropylene given that these are the 
largest flare systems in the Miscellaneous Organic Chemical 
Manufacturing source category and because they are controlling olefinic 
vent gases that contain ethylene and propylene, which have been shown 
in our data to exhibit certain operating scenarios where over-assisting 
and deteriorated flare performance could occur.
    Lastly, we agree with commenters that the language at 40 CFR 
63.2450(e)(5) could be construed as ambiguous for purposes of 
controlling ethylene oxide emissions. As such, we are clarifying in the 
rule text that our intent was to control all emissions generated from 
affected sources ``in ethylene oxide service,'' as that term is defined 
in the final rule.
    Comment: We received comments in support of and against the 
proposed work practice requirements for visible emissions and flare tip 
velocity. One commenter said that MON flares operate similarly to 
refinery flares in that MON flares are typically designed with a 
``smokeless capacity'' for normal operations and a ``hydraulic load 
capacity'' to handle large volumes of flare gas in an emergency. The 
commenter said that it was reasonable for the EPA to use smoking and 
tip velocity events reported for ethylene production and refineries to 
develop emergency flaring provisions for the Miscellaneous Organic 
Chemical Manufacturing source category because the data on the number 
of visible emissions events and velocity exceedances for MON flares are 
not comprehensive of all MON facilities in the subset identified by the 
EPA. However, the commenter said that because ethylene flares are twice 
as likely to have visible emissions events as refinery flares, and 
because it is reasonable to use smoking event data for ethylene flares 
to represent MON flares, the EPA should set the backstop for the work 
practice standard to 6 smoking events in 3 years for MON flares in the 
identified subset.
    Another commenter objected to the EPA's proposed emergency flaring 
provisions for smoking flares and said that the provisions are 
arbitrary and capricious because they do not meet the requirement from 
CAA section 112(h) that work practice standards be consistent with CAA 
section 112(d)(2) and (d)(3). The commenter argued that the EPA's 
assumption regarding the frequency of emergency flaring events using 
events at refineries and ethylene production facilities does not 
satisfy the requirement in CAA section 112(d)(2) that the Administrator 
``determine'' what is achievable regarding the frequency of emergency 
flaring events. The commenter said the EPA's reliance on data from 
refineries and ethylene production facilities, and lack of analysis of 
the frequency of emergency flaring events at MON facilities, means that 
the exemption provision violates the CAA section 112(d) requirement 
that the EPA determine what is achievable for sources ``in the category 
or subcategory to which such emission standard applies.'' The commenter 
requested that the EPA remove the emergency flaring provisions because 
the EPA needs to collect data from MON sources to set a standard that 
could satisfy CAA section 112(d)(2) and (d)(3).
    In addition, the commenter said that even though the visible 
emission exemption at issue is for smoking flare events when flares are 
operating above their smokeless capacity, the EPA (in the present 
proposed rule, as well as in its analyses regarding refinery and 
ethylene production flares) only reached conclusions and analyzed data 
regarding what is achievable for smoking flare events regardless of 
whether the flares were operating above or below their smokeless 
capacity. The commenter argued that the EPA has not determined what is 
achievable for flares when operating above their smokeless capacity. 
The commenter also said the EPA has not performed any analysis of how 
often the best performers would exceed flare tip velocity limits when 
operating above smokeless capacity, and the EPA has only purported to 
analyze smoking flare events (without regard to whether the events 
occurred above smokeless capacity). The commenter stated that the EPA 
also ignored data that contradict its conclusion regarding the 
exemption allowing flare tip velocity events because the ACC data that 
the EPA relied upon to establish the emergency flaring exemption in the 
ethylene production proposal reported no tip velocity events among any 
of the 45 flares from the ACC survey. The commenter contended that the 
ACC data suggest that the best performing flares (at least at ethylene 
production facilities) would have zero tip velocity exceedances over 
three years, meaning that the EPA's conclusion that the best performers 
would have one or two exceedances over that same period is arbitrary 
and capricious and contrary to CAA section 112(d). The commenter stated 
that, unlike the MON proposed rule, the EPA finalized in the Ethylene 
Production RTR rulemaking the requirement that the maximum flare tip 
velocity operating limit applies at all times.
    Response: We are taking final action on the proposed work practice 
requirements for visible emissions and flare tip velocity as several 
commenters suggested. We disagree that we should set the backstop for 
the work practice standard to 6 smoking events in 3 years for MON 
flares in the identified subset. The commenter did not provide enough 
data (i.e., information on visible emissions from MON flares in the 
identified subset) for the EPA to justify revising the proposed 
requirements. We also disagree with another commenter that we did not 
analyze the frequency of emergency flaring events at MON facilities and 
that reliance on data from refineries and ethylene production 
facilities means that the exemption provision violates the CAA section 
112(d) requirement that the EPA determine what is achievable for 
sources ``in the category or subcategory to which such emission 
standard applies.'' We contend that the data used in our analysis 
represents the best available data available to the agency for the 
Miscellaneous Organic Chemical Manufacturing Source Category. As stated 
in our technical memorandum, Control Option Impacts for Flares Located 
in the Miscellaneous Organic Chemical Manufacturing Source Category, 
available in the docket for this rulemaking (see Docket Item No. EPA-
HQ-OAR-2018-0746-0006), although ACC provided some information about 
visible emissions events and velocity exceedances for MON flares, the 
data are not comprehensive of all MON flares in the identified subset. 
Therefore, we did not use the ACC data to determine the number of 
smoking and tip velocity events that we used in our analysis for

[[Page 49117]]

the Miscellaneous Organic Chemical Manufacturing source category, but 
rather this information is based on smoking and tip velocity events 
reported for two different source categories (refineries and ethylene 
production). Best performing flares at refineries have events once 
every 6 years, and ethylene flare best performers have events once 
every 7 years. We noted that some flares control process gases from 
both the Miscellaneous Organic Chemical Manufacturing source category 
and from the Ethylene Production source category at the same facility. 
Therefore, we surmised that it is likely that MON flares in the 
identified subset would have a visible emissions event between every 6 
and 7 years. As a conservative approach, we then concluded the best 
performing MON flares in the identified subset have a visible emissions 
event once every 7 years. Even if the best-performing flare 
``typically'' only has one event every 7 years, the fact that visible 
emissions events are random by nature (unpredictable, not under the 
direct control of the owner or operator) makes it difficult to use a 
short term time span to evaluate a backstop to ensure an effective work 
practice standard. Thus, when one considers a longer time span of 20 
years, our analysis shows that 3 smoking events in 3 years would appear 
to be ``achievable'' for the average of the best performing flares. 
That said, we do acknowledge that the data we received from ACC's 
survey from the Ethylene Production source category identifies zero 
exceedances of the flare tip velocity during a smoking event. Also, the 
MON-specific data that ACC provided is limited to only one MON 
facility, of which 44 of these events were associated with pressure-
assisted flares, and no velocity events were reported by any other MON 
site. Thus, we agree with the commenter that our proposed determination 
of the frequency of these velocity events at the best performing 
sources is not supported, and we are not finalizing the proposed work 
practice standard for when the flare vent gas flow rate exceeds the 
smokeless capacity of the flare and the tip velocity exceeds the 
maximum flare tip velocity operating limit. Instead, we are finalizing 
provisions that require compliance with the maximum flare tip velocity 
operating limit at all times, regardless of whether the flare is 
operating above its smokeless capacity.
b. PRDs
    Comment: Several commenters supported the PRD work practice 
requirements, agreeing it is technically and economically infeasible to 
establish emission limitations for PRDs that are not designed to vent 
through a control system. The commenters added that the EPA's approach 
meets their obligations under CAA section 112. One commenter noted that 
even states that have stringently regulated PRDs, such as California, 
have not established numerical emissions limits. The commenter added 
that because these events are triggered by a variety of non-routine 
process conditions across a variety of different processes, there is no 
MACT-level technology that can be applied to this category of PRDs to 
limit emissions to a certain quantity or concentration. The commenter 
noted that the MACT requirements should be consistent with other 
regulatory obligations such as the OSHA Process Safety Management (PSM) 
program and the EPA CAP program.
    Another commenter contended that work practice standards are only 
allowed in lieu of numerical emission standards under narrow 
circumstances, and the EPA may not set work practice standard unless 
the EPA determines that the pollutant cannot be emitted ``through a 
conveyance designed and constructed to emit or capture such pollutant'' 
or that ``application of measurement methodology to a particular class 
of sources is not practicable due to technological and economic 
limitations.'' The commenter added that even when the EPA sets a work 
practice standard, such a standard must require the ``maximum'' degree 
of emission reduction ``achievable'' and still be consistent with 
section 112(d)(2) and (3) to apply continuously. The commenter added 
that work practice standards for PRDs are not allowed because 
traditional emission restrictions are feasible to restrict the excess 
emissions the EPA seeks to authorize. The commenter noted that CAA 
section 112(h) requires the EPA to make a very specific finding that 
numeric emissions are infeasible, and the EPA has not satisfied that 
requirement for PRDs. The commenter claimed that the EPA's assertion 
that emissions cannot be measured is contradicted by its requirement 
that sources calculate their emissions during any PRD release to the 
atmosphere, and the EPA's reporting and recordkeeping requirements 
mandate facilities ``calculate the quantity of organic HAP released 
during each pressure release event.'' The commenter also noted that 
local jurisdictions require monitoring to measure such releases.
    A commenter contended that because PRDs at MON sources are 
currently uncontrolled, the EPA must set a standard that satisfies CAA 
section (d)(2) and (3) and reflects what the relevant best-performing 
existing sources have ``achieved'' and the ``maximum achievable degree 
of emission reduction.'' The commenter continued that the EPA must set 
the floor by assessing the emissions limitation achieved by the best 
performing 12 percent of existing sources and that cost cannot be 
considered in setting the MACT floor, per CAA section (d)(3). The 
commenter contended the EPA must set a zero-emission limit for all PRDs 
because the best-performing PRDs emit nothing. The commenter stated 
that in the proposed rule, the EPA has not attempted to evaluate the 
actual performance of PRDs at MON sources. The commenter added that in 
the absence of emissions data, the EPA may infer that the MACT floor is 
at least as stringent as an existing regulatory limit, such as 
California's South Coast Air Quality Management District (SCAQMD) and 
the Bay Area Air Quality Management District (BAAQMD) for similar 
sources. The commenter noted that both agencies have adopted more 
stringent emission limitations and leak and repair programs. The 
commenter also added that the EPA has ample emissions data 
demonstrating that emissions of at least 12 percent of existing PRDs 
nationwide reflect at least the use of a well-performing flare. As an 
example, the commenter stated that the TCEQ data the EPA relied on in 
the ethylene production rule demonstrated that 23 percent of facilities 
had no atmospheric releases on a properly operating PRD. Another 
commenter also said the EPA should evaluate the data that SCAQMD is 
considering in that rulemaking and further strengthen the requirements 
for MON sources.\21\
---------------------------------------------------------------------------

    \21\ Commenter provided the following reference: SCAQMD, Rule 
and Control Measure Forecast (Mar 6, 2020), http://www.aqmd.gov/docs/default-source/Agendas/Governing-Board/2020/2020-mar6-016.pdf?sfvrsn=6, (stating that SCAQMD is considering proposed 
revisions to ``improve the effectiveness, enforceability, and 
clarity of the rule. Other proposed amendments may be needed to 
further reduce emissions from operations, implement early leak 
detection, odor minimization plans, and enhanced emissions and 
chemical reporting'').
---------------------------------------------------------------------------

    One commenter contended that the EPA did not analyze the cost of 
construction and installation of continuous monitoring systems in order 
to measure release events for PRDs that vent to atmosphere. The 
commenter noted that the EPA's reporting and recordkeeping requirements 
mandate facilities ``calculate the quantity of organic [hazardous air 
pollutants] released during each pressure release event'' and that a 
SCAQMD report

[[Page 49118]]

found that ``new (wireless) technology allows continuous monitoring of 
PRDs without significant capital expense and makes it easy for 
operators to identify valve leaks.'' The commenter added that there are 
multiple vendors of this technology, including one vendor with whom the 
EPA met during the refineries rulemaking, and this technology is 
already in use at refineries in the United States. The commenter 
claimed that refineries have found that implementing this kind of 
monitoring technology saves money. The commenter added that in the 
ethylene production rulemaking, the EPA relied on TCEQ data from seven 
ethylene production facilities that reported the quantity of HAP 
emissions released during specific PRD release events indicating that 
not only is it possible to measure PRD emissions, but also that they 
actually have been measured and that the EPA itself acknowledges this 
fact.
    Response: We disagree with some commenters' assessment that numeric 
emission limit standards are feasible and must be established for PRDs 
that vent to the atmosphere. We are finalizing a work practice standard 
for PRDs, as proposed, that consists of using at least three prevention 
measures and performing root cause analysis and corrective action in 
the event that a PRD does release emissions directly to the atmosphere. 
We also maintain the rationale provided in the proposal preamble (84 FR 
69207, December 17, 2019) for this work practice standard, where we 
specifically considered the issue related to constructing a conveyance 
and quantitatively measuring PRD releases and concluded that these 
measures were not practicable and that a work practice standard was 
appropriate. Owners or operators can estimate the quantity of HAP 
emissions released during a PRD release event based on vessel operating 
conditions (temperature and pressure) and vessel contents when a 
release occurs, but these estimates do not constitute a measurement of 
emissions or emission rate within the meaning of CAA section 112(h). 
The monitoring technology suggested by the commenter is adequate for 
identifying PRD releases and is one of the acceptable methods that 
facility owners or operators may use to comply with the continuous 
monitoring requirement. However, we disagree that it is adequate for 
accurately measuring emissions for purposes of determining compliance 
with a numeric emission standard. For example, the technology cited by 
the commenter is a wireless monitor that provides an indication that a 
PRD release has occurred, but it does not provide information on either 
release quantity or composition. PRD release events are characterized 
by short, high pressure, non-steady state conditions that make such 
releases difficult to quantitatively measure. As discussed in the 
proposal preamble (84 FR 69207, December 17, 2019), we have not 
identified any available, technically feasible CEMS that can accurately 
determine a mass release quantity of VOC or HAP given the flow, 
composition, and composition variability of potential PRD releases that 
vent to the atmosphere from MCPUs. Therefore, it is also economically 
infeasible at this time to establish emission limitations for PRDs 
given that no such system exists. As such, we maintain our position 
that the application of a work practice standard is appropriate for 
PRDs.
    As a general matter, CAA section 112 requires MACT for existing 
sources to be no less stringent than ``the average emission limitation 
achieved by the best performing 12 percent of the existing sources (for 
which the Administrator has emissions information) . . .'' [(CAA 
section 112(d)(3)(A)]. ``Emission limitation'' is defined in the CAA as 
``. . . a requirement established by the State or Administrator which 
limits the quantity, rate, or concentration of emissions of air 
pollutants on a continuous basis, including any requirement relating to 
operation or maintenance of a source to assure continuous emission 
reduction, and any design, equipment, work practice, or operational 
standard promulgated under this chapter'' [CAA section 302(k)]. The EPA 
specifically considers existing rules from state and local authorities 
in identifying the ``emission limitations'' for a given source. We then 
identify the best performers to identify the MACT floor (the no less 
stringent than level) for that source. The EPA identified the 
requirements established in the SCAQMD and BAAQMD rules,\22\ and the 
Chemical Accident Prevent Provisions rule (40 CFR part 68) as the basis 
of the MACT floor because they represented the requirements applicable 
to the best performing sources. Work practice standards are established 
in place of a numeric limit where it is not feasible to establish such 
limits. Thus, in a case such as this, where the EPA has determined that 
it is appropriate to establish work practice standards, it was 
reasonable for the EPA to identify the rules that impose the most 
stringent requirements and, thus, represent what applies to the best 
performers, and then to apply the requirements from those rules as 
MACT.
---------------------------------------------------------------------------

    \22\ While there are not MON facilities in the SCAQMD or BAAQMD, 
as stated in the proposal preamble (84 FR 29207), we believe that 
MON facilities are complying with these rules via company-wide best 
practices. There are companies that own MON facilities and petroleum 
refineries, and there are petroleum refineries located in these 
AQMDs.
---------------------------------------------------------------------------

    We recognize that the proposed standard for PRDs did not exactly 
mirror the SCAQMD, BAAQMD, or Chemical Accident Prevent Provisions 
rules, but we consider the requirements to be comparable. For example, 
we did not include a provision similar to that in the SCAQMD rule that 
excludes releases less than 500 lbs/day from the requirement to perform 
a root cause analysis; that provision in the SCAQMD rule does not 
include any other obligation to reduce the number of these events. 
Similarly, we did not include a provision that only catastrophic PRD 
releases must be investigated. Rather than allowing unlimited releases 
less than 500 lbs/day or that are not considered catastrophic, we 
require a root cause analysis for releases of any size. Because we 
count small releases that the SCAQMD rule does not regulate at all, we 
considered it reasonable to provide a higher number of releases prior 
to considering the owner or operator to be in violation of the work 
practice standard. We also adopted the three prevention measures 
requirements in the BAAQMD rule with limited modifications. We also 
note that a facility cannot simply choose to release pollutants from a 
PRD; any release that is caused willfully or caused by negligence or 
operator error is considered a violation.
    Comment: Two commenters supported subcategorizing PRDs and agreed 
with the EPA's rationale for doing so. However, one commenter contended 
that the EPA has unlawfully categorized PRDs by control (i.e., PRDs 
that vent through a closed vent system to a control device or to a 
process, fuel gas system, or drain system and PRDs that vent to the 
atmosphere). The commenter added that the best-controlled PRDs are 
routed to processes with no discharge to the environment, and well-
controlled PRDs are vented to a control system rather than directly to 
the atmosphere. The commenter stated that the EPA must determine the 
appropriate MACT floor for new and existing PRDs based on the best 
performing PRDs and also require ``beyond the floor'' options, but 
because PRDs nationwide reflect at least the use of a control system, 
the EPA may not establish a limitation that is less stringent than 
venting to a control system. The commenter contended that because the 
best-controlled PRDs have

[[Page 49119]]

no emissions, the EPA must set a zero-emission limit for all PRDs.
    One commenter also contended that the EPA did not explain why 
additional flares cannot be installed by MON facilities to meet a 
standard prohibiting uncontrolled PRD releases. The commenter stated 
that the EPA did not estimate the number of new flares that would be 
installed, based on data of the number of atmospheric PRDs reported at 
MON facilities.
    Response: Regarding subcategorization of PRDs, the only information 
we have available about when PRD releases occur is from those PRDs that 
release directly to atmosphere (see the technical memorandum, Review of 
Regulatory Alternatives for Certain Vent Streams in the Miscellaneous 
Organic Chemical Manufacturing Source Category, available in the docket 
for this rulemaking, see Docket Item No. EPA-HQ-OAR-2018-0746-0010). 
The work practice standard we are finalizing provides a comprehensive 
program to manage entire populations of PRDs; includes prevention 
measures, continuous monitoring, root cause analysis, and corrective 
actions; and addresses the potential for violations for multiple 
releases over a 3-year period. We followed the requirements of section 
112 of the CAA, including CAA section 112(h), in establishing what work 
practice constituted the MACT floor. We provide further details on our 
rationale to develop a work practice standard in previous responses to 
comments in this section of this preamble and the preamble to the 
proposed rule.
    We disagree with the comment that the EPA did not explain why 
additional flares could not be installed to control releases from PRDs. 
We conducted a beyond-the-floor analysis at proposal that examined the 
option of controlling all PRDs with a control device. 84 FR 69209. As 
part of this analysis, we estimated for all MON facilities, assuming 25 
percent to 50 percent of PRDs already vent to a control device, the 
capital cost for controlling the remaining PRDs ranges from $2.54 
billion to $5.07 billion, and the annualized cost ranges from $330 
million to $660 million. Because the incremental cost effectiveness for 
requiring control of all PRDs that vent to atmosphere exceeds $80 
million per ton of HAP reduced, the beyond-the-floor option was 
determined not to be cost-effective. Details of the beyond-the-floor 
analysis are available in the memorandum, Review of Regulatory 
Alternatives for Certain Vent Streams in the Miscellaneous Organic 
Chemical Manufacturing Source Category, which is available in the 
docket for this rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-
0010).
    Comment: We received comments in support of and against the 
proposed requirements allowing PRDs to discharge to the atmosphere. 
Some commenters supported allowing a limited number of PRD releases at 
MON facilities. The commenters supported the EPA's assessment that even 
at the best performing sources, releases from PRDs are likely to occur 
and cannot be safely or economically routed to a control device. Two 
commenters contended there was a wide variety of situations that can 
trigger a PRD actuation and noted it was impossible to predict which 
PRDs will release during a given year. One commenter opposed any limit 
on the number of PRD releases because they are needed for safety 
reasons. However, the commenter added that if the EPA is going to 
finalize a limit on the number of authorized PRD venting events, they 
supported allowing more than one release in a 3 calendar year period.
    Two commenters identified several situations where PRDs are 
designed to vent to the atmosphere instead of a flare or other control 
device due to safety concerns. One commenter also identified situations 
where it was technically not possible to collect discharges from PRDs. 
One commenter supported the EPA's conclusion that it was not cost 
effective to control all PRDs that vent to the atmosphere.
    Another commenter noted that PRDs on process equipment such as 
distillation columns and steamers are typically intended for emergency 
venting, and these devices are the last (mechanical) line of defense to 
avoid over-pressurization situations. The commenter added that 
pollution control devices are intended for normal process operations 
and are not commonly designed to handle the flow that would result from 
an emergency PRD release. The commenter concluded that the capture of 
releases from emergency over-pressurizations has the potential to 
create a new hazard.
    One commenter opposed allowing PRDs to discharge to the atmosphere. 
The commenter stated that the EPA cannot use CAA section 112(h) to 
circumvent the emission standards of equipment connected to PRDs and 
smoking flares through uncontrolled releases from these devices. The 
commenter cited the court decision U.S. Sugar Corp. v. EPA, 830 F.3d at 
608 (D.C. Cir. 2016) that exemptions ``cannot be framed in simple 
numerical terms, as, say, an allowance of four excessive discharges per 
year,'' as doing so would give emitters ``a license to dump wastes at 
will on several occasions annually,'' and Weyerhaeuser Co. v. Costle, 
590 F.2d at 1011, 1057 (D.C. Cir. 1978) that ``no control'' is not a 
standard--it is an exemption. The commenter continued to cite 
Weyerhaeuser Co. v. Costle that malfunctions and force majeure events 
are appropriately dealt with through ``the administrative exercise of 
case-by-case enforcement discretion, not for specification in advance 
by regulation.'' The commenter contended that finalizing these 
exemptions would incentivize facilities to install redundant PRDs or 
flares, and operators could cycle through PRDs, sealing off each one 
after a release event to avoid repeated violations of the underlying 
equipment's emission standards. The commenter added that emissions 
could be routed away from controlling flares to an endless number of 
cycling pressure release devices resulting in unlimited emissions with 
no technical violation. The commenter concluded that treating releases 
from PRDs and smoking flares as violations would incentivize operators 
to do the planning/maintenance, etc., to eliminate the root causes of 
these releases.
    The commenter stated that allowing PRD releases is not consistent 
with the technology-forcing requirements from CAA section 112(d) and is 
arbitrary and capricious. The commenter contended that neither the 
proposed rule nor the EPA's supporting memorandum regarding the work 
practice standards for PRD releases to the atmosphere discusses whether 
the number of uncontrolled releases that would be a violation of the 
standard reflects what is achievable under CAA section 112(d). The 
commenter added that the exemption violates CAA sections 112(d) and (h) 
because the EPA has not analyzed what the best performers can achieve 
with respect to the number of uncontrolled PRD releases to the 
atmosphere. The commenter contended that the EPA's conclusions were 
based on a Monte Carlo analysis of random rare events conducted for the 
Petroleum Refinery Sector rule, for smoking flare events--not PRD 
releases. The commenter added that the EPA has conducted no analysis of 
how often the best performing MON facilities have uncontrolled PRD 
releases to the atmosphere. The commenter concluded that because the 
EPA did not analyze the rate of PRD releases at MON facilities, the 
EPA's exemption for PRD releases to the atmosphere is contrary to CAA 
section 112(h) in that work practice standards be ``consistent with the 
provisions of subsection (d) or (f).'' The commenter noted that CAA 
section

[[Page 49120]]

112(d) mandates that standards require the ``maximum'' degree of 
reduction in emissions that the Administrator ``determines is 
achievable'' for sources ``in the category or subcategory to which such 
emission standard applies.''
    The commenter added that the EPA did not ``determine'' what is 
``achievable'' for PRDs, as required by CAA section 112(d)(2) through 
(3), because the EPA only analyzed what is achievable for flares. The 
commenter contended that PRDs are not flares, and vice versa, and PRDs 
could release to the atmosphere at much different rates from the rates 
at which flares have smoking events. The commenter stated that even if 
the EPA could lawfully and non-arbitrarily base the limit on MON PRD 
releases to the atmosphere on the rate at which flares at refineries 
supposedly have smoking events, the industry data and analysis that the 
EPA relies upon to try to craft the exemption has problems that also 
render it contrary to statutory requirements and is arbitrary and 
capricious. The commenter explained that the analysis began by relying 
on an unsubstantiated industry claim that an American Petroleum 
Institute and American Fuel & Petrochemical Manufacturers survey of 148 
flares (which industry said was around 30 percent of flares) showed 
that, on average, a flare will have a smoking event once every 4.4 
years. The commenter added that working from the unsubstantiated 
industry rate of one event every 4.4 years, the EPA then just assumed 
without support that the best performers would have an event once in 
every six years (e.g., better than the average of once every 4.4 
years). The commenter stated that the EPA then used that assumed and 
unsubstantiated once-per-six-years frequency to conduct its Monte Carlo 
analysis. The commenter contended that the EPA's assumption that the 
best performers would have one event every six years cannot satisfy CAA 
section 112(d)'s command that the agency determine what the best 
performers can achieve, nor does that assumption satisfy the 
requirements that the agency engage in non-arbitrary rulemaking and 
support its factual determinations with substantial evidence. The 
commenter also added that the assumptions that the EPA made regarding 
the rate of PRD releases to the atmosphere in establishing the 
exemption conflict with the assumptions that the EPA made regarding 
those releases in calculating the cost for MON facilities to implement 
the work practice standard, rendering the exemption arbitrary and 
capricious. The commenter stated that the EPA based the PRD exemption 
on an analysis that assumed that the best performing flare would have a 
16.7-percent probability of having an event every year, and the cost 
analysis assumed that only 10 percent of PRDs at MON facilities would 
have a release every year. The commenter also added that information 
collected for its recent proposed NESHAP rule for ethylene production 
facilities showed that only 4.4 percent of PRDs in that source category 
would release to the atmosphere annually. The commenter stated that the 
EPA's cost analysis only looked to the release rates for all PRDs and 
not the best-performing ones. The commenter stated that the best 
performers would presumably release to the atmosphere even less 
frequently. The commenter added that compliance data for refinery PRDs 
shows that those devices release to the atmosphere far less frequently 
than the EPA assumes and that the best-performing uncontrolled PRDs are 
likely to have no atmospheric releases over a 3-year period. Another 
commenter concluded that the EPA's proposal to give each uncontrolled 
PRD one or two free passes before an atmospheric release becomes a 
deviation is inconsistent with CAA section 112(d)(2) and (3) and 
arbitrary and capricious. The commenter reviewed some compliance 
reports from calendar year 2019 for refineries and determined that 
among the 998 uncontrolled PRDs, there was only one 3-minute release to 
the atmosphere. The commenter calculated that these 998 uncontrolled 
PRDs would experience only 7.2 atmospheric releases (or less) over 3 
years, and an average of 0.007 (or less) releases per uncontrolled PRD 
over 3 years. The commenter concluded that the average PRD from the 
best performers has zero releases to the atmosphere over 3 years.
    Response: The EPA is taking final action on the proposed PRD work 
practice standards as requested in a number of comment letters.
    We disagree with the commenter that stated that work practice 
standards are not appropriate for PRD releases in the Miscellaneous 
Organic Chemical Manufacturing source category. At proposal, the EPA 
provided extensive discussions on why it was appropriate to establish a 
work practice standard for PRDs that vent to atmosphere, under CAA 
section 112(h). 84 FR 69206-69209, December 17, 2019. We explained that 
no MON facility is subject to numeric emission limits for PRDs that 
vent to the atmosphere. We posited that it was not appropriate to 
subject PRDs that vent to the atmosphere to numeric emission limits due 
to technological and economical limitations that make it impracticable 
to measure emissions from such PRDs. We further explained that CAA 
section 112(h)(1) allows the EPA to prescribe a work practice standard 
or other requirement, consistent with the provisions of CAA section 
112(d) or (f), in those cases where, in the judgment of the 
Administrator, it is not feasible to enforce an emission standard. 
Additionally, we explained that CAA section 112(h)(2)(B) defines the 
term ``not feasible'' in this context as meaning that ``the application 
of measurement technology to a particular class of sources is not 
practicable due to technological and economic limitations.'' We also 
noted that the basis of the work practice standards promulgated for PRD 
releases in the Petroleum Refinery Sector RTR (80 FR 75178, December 1, 
2015) were our underlying basis for the proposed work practice 
standards at MON facilities.
    With regard to the comments about the PRDs and the smoking flare 
requirements being exemptions, we note that CAA section 112 standards 
apply at all times to PRDs and to flares controlling vent gas streams 
from affected emission sources at MON facilities. For PRDs, facilities 
must implement a system consisting of at least three redundant 
prevention measures to minimize releases and must monitor PRDs for any 
releases, if they were to occur. For flares, facilities still must 
comply with the underlying combustion efficiency standards (e.g., 
NHVcz) to ensure the flare is achieving the level of destruction 
efficiency required by the underlying MACT standards in the MON.
    The comments about facilities continuously installing redundant 
PRDs or closing up PRDs and opening new ones to be able to have as many 
PRD events as possible without violating the PRD work practice are 
hypothetical and the EPA has no information to support such a strategy. 
In addition, MON facilities must operate and maintain any affected 
source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions, and setting up 
such a strategy would be inconsistent with the General Duty 
requirements of 40 CFR 63.2450(u). Also, the part 63 General Provisions 
contain a circumvention provision at 40 CFR 63.4(b) that states in part 
that ``no owner or operator subject to the provisions of this part 
shall build, erect, install, or use any article, machine, equipment, or 
process to conceal an emission that

[[Page 49121]]

would otherwise constitute noncompliance with a relevant standard.'' 
Thus, a source that took such hypothetical actions as the commenter 
suggests would be open to an enforcement action for violating the 
circumvention provision.
    The commenter opposed the PRD work practice and provided additional 
information about PRD releases from Petroleum Refineries. Much of what 
was provided by the commenter is irrelevant to the final PRD work 
practice or is insufficient for the Agency to use to update the work 
practice standards we are finalizing for PRDs at MON facilities. The 
EPA notes that the PRDs at Petroleum Refineries are already subject to 
the work practice standards we are finalizing in this action. In 
setting the refineries work practice, the EPA conducted a Monte Carlo 
analysis spanning 20 years. Given that the Agency lacks specific PRD 
release information and smoking flare information for MON sources, we 
stated in our technology review memorandum at proposal that we would 
consider information from other source categories like Petroleum 
Refineries and Ethylene Production facilities when determining what is 
achievable for the best performing sources in the Miscellaneous Organic 
Chemical Manufacturing source category and we made reasonable estimates 
where needed for estimated cost impacts of implementing the work 
practice standards we are finalizing for these sources. If anything, 
the refinery compliance report data provided by the commenter show that 
the work practice standards we finalized for Petroleum Refineries are 
quite effective at minimizing PRD releases to the atmosphere and should 
translate to being effective at minimizing emissions from PRD releases 
at MON facilities as well. As the commenter stated, among the 998 
uncontrolled PRDs reported in the compliance reports that were reviewed 
from calendar year 2019, there was only one three-minute release to the 
atmosphere.
    Comment: One commenter disagreed with requiring a root cause 
analysis and corrective action in every situation in which a PRD 
releases to the atmosphere. The commenter noted that under the Chemical 
Accident Prevention Program, an incident investigation with root cause 
analysis is required only when the release was a catastrophic release 
or could reasonably have resulted in a catastrophic release. The 
commenter added that the EPA has not established sufficient evidence to 
indicate that a root cause analysis is being performed by the best 
performing sources in the MON category routinely for all PRD releases 
regardless of whether they meet the definition of ``catastrophic 
release.''
    Response: As previously mentioned in this section of this preamble, 
the work practice standard we are finalizing provides a comprehensive 
program to manage entire populations of PRDs, includes prevention 
measures, continuous monitoring, root cause analysis, and corrective 
actions, and addresses the potential for violations for multiple 
releases over a 3-year period. Implementing measures such as requiring 
root cause analysis and corrective action analysis will ensure that the 
work practice standards are effective and that the best PRD release 
management practices are followed so that the same events do not recur 
in the future. The commenter also does not provide any data to support 
their assertion that the best performers do not conduct a root cause/
corrective analysis after a PRD release occurs. We followed the 
requirements of section 112 of the CAA, including CAA section 112(h), 
in establishing what work practice constituted the MACT standard for 
PRDs.
c. Degassing Storage Tanks
    Comment: Several commenters requested that the EPA add a standard 
for minimizing emissions arising from degassing storage tanks that are 
complying with the control requirements in Table 4 to 40 CFR part 63, 
subpart FFFF. A commenter explained this request is due to their 
current interpretation of the proposed rule, wherein 40 CFR 63.6(e)(1) 
and 40 CFR 63.2450(a)(1) no longer applies, and thus facilities may be 
required to vent to control devices at all times, even during degassing 
events. A commenter stated that the current rule requires facilities to 
address minimization of emissions from shutdown, which includes 
degassing, in the SSM plan, and that facilities have historically 
considered degassing emissions from shutdown of storage tanks to be 
covered by their SSM plans per 40 CFR 63.6(e)(1) and 40 CFR 
63.2450(a)(1) and relied on the language in 40 CFR 63.6(e)(1) and 40 
CFR 63.2450(a)(1) that back-up control devices are not required. The 
commenter requested the EPA subcategorize storage vessel degassing 
emissions as maintenance vents based on class, just as the EPA proposed 
for process vents. The commenter contended that the Texas permit 
conditions presented in the memorandum, Review of Regulatory 
Alternatives for Certain Vent Streams in the Ethylene Production Source 
Category, available in the docket for this rulemaking, apply equally to 
both maintenance vents and degassing of storage tanks and stated these 
permit conditions reflect what the best performers have implemented for 
storage tank degassing (for both fixed and floating roofs) for both new 
and existing sources. According to the commenters, it is not feasible 
to control all the emissions from the entire storage tank emptying and 
degassing event, and at some point the storage tank must be opened and 
any remaining vapors vented to the atmosphere. The commenter further 
stated that this venting of vapors is similar to the EPA description 
for maintenance vents in the preamble to the proposed rule.
    Another commenter recommended a work practice standard that would 
require emptying the storage vessel as much as practical allows; and if 
the storage vessel is required to be controlled in Table 4 to 40 CFR 
part 63, subpart FFFF, then it would be required to be degassed to a 
control device, fuel gas system, or process prior to opening to the 
atmosphere. The commenter also recommended that if the storage vessel 
is not required to be controlled in Table 4 to 40 CFR part 63, subpart 
FFFF, then it could be vented to atmosphere after removing as much 
liquid as practical.
    Response: We agree with the commenters that complying with the 
storage tank requirements in Table 4 to 40 CFR part 63, subpart FFFF, 
is not appropriate during storage tank degassing events and a separate 
standard for storage tank degassing is necessary, due to the nature of 
the activity. With the removal of SSM requirements in this final rule, 
a standard specific to storage tank degassing does not exist when 
storage tanks are using control devices to comply with the requirements 
in Table 4 to 40 CFR part 63, subpart FFFF. We also agree with the 
commenters that storage tank degassing is similar to maintenance vents 
(e.g., equipment openings) and that there must be a point in time when 
the storage tank can be opened and any emissions vented to the 
atmosphere. In response to this comment, we reviewed available data to 
determine how the best performers are controlling storage tank 
degassing emissions.
    We are aware of three regulations regarding storage tank degassing, 
two in the state of Texas and the third for the SCAQMD in California. 
Texas has degassing provisions in the Texas Administrative Code (TAC) 
\23\ and

[[Page 49122]]

through permit conditions (as noted by the commenter),\24\ while Rule 
1149 contains the SCAQMD degassing provisions.\25\ The TAC requirements 
are the least stringent and require control of degassing emissions 
until the vapor space concentration is less than 35,000 ppmv as methane 
or 50 percent of the lower explosive limit (LEL). The Texas permit 
conditions require control of degassing emissions until the vapor space 
concentration is less than 10 percent of the LEL or until the VOC 
concentration is less than 10,000 ppmv, and SCAQMD Rule 1149 requires 
control of degassing emissions until the vapor space concentration is 
less than 5,000 ppmv as methane. The Texas permit conditions requiring 
compliance with 10 percent of the LEL and SCAQMD Rule 1149 control 
requirements are considered equivalent because 5,000 ppmv as methane 
equals 10 percent of the LEL for methane.
---------------------------------------------------------------------------

    \23\ See 30 TAC Chapter 115, Subchapter F, Division 3, available 
at https://texreg.sos.state.tx.us/public/readtac%24ext.ViewTAC?tac_view=5&ti=30&pt=1&ch=115&sch=F÷=3&rl=Y.
    \24\ See https://www.tceq.texas.gov/assets/public/permitting/air/Guidance/NewSourceReview/mss/chem-mssdraftconditions.pdf.
    \25\ See http://www.aqmd.gov/docs/default-source/rule-book/reg-xi/rule-1149.pdf.
---------------------------------------------------------------------------

    MON facilities located in Texas are subject to the permit 
conditions, but no MON facilities are subject to the SCAQMD rule. Of 
the 201 currently operating MON facilities, 39 are in Texas. Therefore, 
the Texas permit conditions relying on storage tank degassing until 10 
percent of the LEL is achieved reflect what the best performers have 
implemented for storage tank degassing, and we considered this 
information as the MACT floor for both new and existing sources. 
Notably, this also aligns with the commenter's assessment.
    We reviewed Texas permit condition 6 (applicable to floating roof 
storage tanks) and permit condition 7 (applicable to fixed roof storage 
tanks) for key information that could be implemented to form the basis 
of a standard for storage tank degassing. The Texas permit conditions 
require control of degassing emissions for floating roof and fixed roof 
storage tanks until the vapor space concentration is less than 10 
percent of the LEL. The permit conditions also specify that facilities 
can also degas a storage tank until they meet a VOC concentration of 
10,000 ppmv, but we do not consider 10,000 ppmv to be equivalent to or 
as stringent as the compliance option to meet 10 percent of the LEL and 
are not including this as a compliance option. We also do not expect 
the best performers would be using this concentration for compliance, 
which is supported by the commenters recommending the requirements 
mimic the maintenance vent requirements and because the Texas permit 
conditions allow facilities to calibrate their LEL monitor using 
methane. Storage tanks may be vented to the atmosphere once the storage 
tank degassing concentration threshold is met (i.e., less than 10 
percent of the LEL) and all standing liquid has been removed from the 
tank to the extent practicable. These requirements are considered MACT 
for both new and existing sources, and we are finalizing these 
requirements at 40 CFR 63.2470(f).
    We calculated the impacts due to controlling storage tank degassing 
emissions by evaluating the population of storage tanks that are 
subject to control under Table 4 to 40 CFR part 63, subpart FFFF, and 
not located in Texas. Storage tanks in the Miscellaneous Organic 
Chemical Manufacturing source category in Texas would already be 
subject to the degassing requirements, and there would not be 
additional costs or emissions reductions for these facilities. We 
estimated there are an average of 9 storage tanks per facility, based 
on a 2003 memorandum on MON storage tanks, and applied that to the 162 
MON facilities that are not located in Texas, resulting in 1,458 
storage tanks newly applicable to tank degassing requirements. Based on 
a review of CAA section 114 survey responses for ethylene production 
facilities, most storage tanks are degassed an average of once every 14 
years. Using this average and the population of storage tanks that are 
not in Texas, we estimated 104 storage tank degassing events would be 
newly subject to control each year. Controlling storage tank degassing 
would reduce HAP emissions by 86 tons per year, with a total annual 
cost of approximately $489,000. See the technical memorandum, Storage 
Tank Degassing Cost and Emissions Impacts for the Miscellaneous Organic 
Chemical Manufacturing Source Category For the Final Rule, which is 
available in the docket for this rulemaking, for details on the 
assumptions and methodologies used in this analysis.
    We also considered options beyond-the-floor, but we did not 
identify and are not aware of storage tank degassing control provisions 
more stringent than those discussed above and being finalized in this 
rule; therefore, no beyond-the-floor option was evaluated.
    The remaining comments and our specific 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.
4. What is the rationale for our final approach and final decisions for 
the revisions pursuant to CAA section 112(d)(2) and (3)?
    We evaluated all of the comments on the EPA's proposed amendments 
to revisions for flares used as APCDs, clarifications for periods of 
SSM and bypasses, including PRD releases, bypass lines on closed vent 
systems, maintenance activities, certain gaseous streams routed to a 
fuel gas system, and requirements for storage tank degassing 
activities. For the reasons explained in section IV.A of the proposal 
preamble (84 FR 69182, December 17, 2019), we find that the flare 
amendments are needed to ensure that flares used as APCDs achieve the 
required level of MACT control and meet 98-percent destruction 
efficiency at all times as well as to ensure that CAA section 112 
standards apply at all times. Similarly, the clarifications for periods 
of SSM and bypasses, including PRD releases, bypass lines on closed 
vent systems, maintenance activities, certain gaseous streams routed to 
a fuel gas system, and standards associated with storage tank emptying 
and degassing events are needed to be consistent with Sierra Club v. 
EPA, 551 F.3d 1019 (D.C. Cir. 2008) to ensure that CAA section 112 
standards apply at all times. More information and rationale concerning 
all the amendments we are finalizing pursuant to CAA sections 112(d)(2) 
and (3) is in the preamble to the proposed rule (84 FR 69182, December 
17, 2019), in section IV.C.3 of this preamble, and in the comments and 
our specific responses to the comments in the document, Summary of 
Public Comments and Responses for the Risk and Technology Review for 
Miscellaneous Organic Chemical Manufacturing, which is available in the 
docket for this rulemaking. Therefore, we are finalizing the proposed 
provisions for flares (except that we are not finalizing the work 
practice standard for velocity exceedances for flares operating above 
their smokeless capacity), finalizing the proposed clarifications for 
periods of SSM and bypasses, including PRD releases, bypass lines on 
closed vent systems, maintenance activities, and certain gaseous 
streams routed to a fuel gas system, and finalizing standards for 
storage tank emptying and degassing events.

[[Page 49123]]

D. Amendments Addressing Emissions During Periods of SSM

1. What amendments did we propose to address emissions during periods 
of SSM?
    We proposed amendments to the MON standards to remove and revise 
provisions related to SSM that are not consistent with the requirement 
that the standards apply at all times. In a few instances, we are 
finalizing alternative standards for certain emission points (i.e., 
emergency flaring, PRDs, maintenance activities, and tank degassing) to 
minimize emissions during periods of SSM to ensure a continuous CAA 
section 112 standard applies ``at all times,'' (see section IV.C of 
this preamble); however for the majority of emission points in the 
Miscellaneous Organic Chemical Manufacturing source category, we 
proposed eliminating the SSM exemptions and to have the MACT standards 
apply at all times. More information concerning the elimination of SSM 
provisions is in section IV.E.1 of the proposal preamble (84 FR 69182, 
December 17, 2019).
2. How did the SSM provisions change since proposal?
    We are finalizing the SSM provisions as proposed (84 FR 69182, 
December 17, 2019) with only minor changes to sufficiently address the 
SSM exemption provisions from subparts referenced by the MON standards, 
and the removal of applicability of 40 CFR 63.6(f)(1) and (h)(1) that 
are directly impacted by the 2008 Court decision.
3. What key comments did we receive on the SSM revisions and what are 
our responses?
    While we are finalizing some alternative standards in this final 
rule for certain emission points during periods of SSM to ensure a 
continuous CAA section 112 standard applies ``at all times,'' (see 
section IV.C of this preamble), we also proposed eliminating the SSM 
exemptions for the majority of emission points in the Miscellaneous 
Organic Chemical Manufacturing source category. This section provides 
comment summaries and responses for the key comments received regarding 
our proposed revisions. Other comment summaries and the EPA's responses 
for additional issues raised regarding these activities as well as 
issues raised regarding our proposed revisions 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.
    Comment: One commenter stated that the proposed malfunction 
standards for PRDs break with prior Agency policy regarding 
malfunctions and the use of case-by-case enforcement discretion to 
address malfunctions. The commenter stated that the agency has 
repeatedly explained why case-by-case evaluation of such issues is the 
only workable approach and has repeatedly finalized prohibitions on 
uncontrolled releases from PRDs that vent directly to the atmosphere, 
fully aware that allowing such releases without an emission limit is a 
malfunction exemption prohibited both by the CAA and the Court's 
decision in Sierra Club. The commenter objected to this change and 
contended that the EPA did not clearly explain this break with prior 
precedent. The commenter noted that the EPA finalized similar 
provisions prohibiting PRD releases in MACT standards for Group IV 
Polymers and Resins, Pesticide Active Ingredient Manufacturing, and 
Polyether Polyols Production. The commenter further stated that the 
Court recently upheld this type of prohibition in Mexichem Specialty 
Resins, Inc. v EPA, 787 F.3d 544, 560-61 (D.C. Cir. 2015) and urged the 
EPA to finalize the standards for PRD as proposed. The commenter noted 
that in light of the EPA's prior policy, prohibiting uncontrolled PRD 
releases is lawful and consistent with the CAA. The commenter stated 
that the EPA has neither provided a reasoned explanation for the 
exemptions nor acknowledged or explained the break in its prior policy 
against malfunction exemptions.
    Furthermore, the commenter observed that uncontrolled PRD releases 
are preventable and avoidable and that they need not occur if a 
facility avoids over-pressure in the system. The commenter referred to 
the proposal preamble, noting that such ``pressure build-ups are 
typically a sign of a malfunction of the underlying equipment,'' and 
PRDs ``are equipment installed specifically to release during 
malfunctions.'' Therefore, the commenter argued that the EPA cannot 
rely on any argument that equipment can fail, that PRDs are necessary 
to address over-pressure and avoid a larger safety incident, and that 
the EPA has not relied on or demonstrated with any evidence that it is 
a valid concern. The commenter stated that even if it may be considered 
by the EPA in an administrative enforcement context or by the courts in 
an enforcement case, the EPA cannot authorize, up front, a whole set of 
problematic releases.
    The commenter argued that it would create a far stronger incentive 
to reduce smoking flares and uncontrolled PRD releases if the EPA 
simply recognized that such uncontrolled releases are prohibited and 
the flare requirements must apply at all times; treating one or two 
exceedances as a non-violation dramatically reduces the incentive for 
facilities to comply with the work practice standards.
    The commenter also noted that the civil penalties available for 
such violations could provide some remedy for the air pollution a 
facility released, even if it were completely out of the facility's 
control. For example, the commenter stated that penalties won by a 
citizen suit may either go into a special fund ``to finance air 
compliance and enforcement activities'' that may help to address some 
part of the pollution or ``be used in beneficial mitigation projects 
which . . . enhance the public health or the environment.''
    Other commenters agreed that the EPA has the authority and 
obligation to adopt work practice standards under the Sierra Club SSM 
decision. The commenters reiterated the Sierra Club decision and said 
the EPA must ensure that some ``emission standard'' applies at all 
times--except that the standard that applies during normal operation 
need not be the same standard for SSM periods. The commenters said the 
requirement for ``continuous'' standards means only that a facility may 
not install control equipment and then turn it off when atmospheric 
conditions are good; it does not mean that work practice standards must 
physically restrict emissions from all equipment at all times. The 
commenters said that the EPA has consistently imposed as ``MACT'' 
standards a variety of work practice obligations that do not prohibit 
or limit emissions to a specified level at all times but rather are 
designed to limit overall emissions from various processes over the 
course of a year. The commenters said the EPA's own LDAR programs 
illustrate this distinction. The commenters contended that no court has 
suggested that periods of ``unlimited emissions'' [e.g., 40 CFR 
63.119(b)(1) (internal floating roof allowed not to contact with stored 
material during filling/emptying); 40 CFR 63.119(b)(6) (covers on tank 
openings may be opened when needed for access to contents); 40 CFR 
63.135(c)(2) (allowing openings on containers as necessary to prevent 
physical damage)] render these requirements insufficient under CAA 
section 112. Rather, the commenters said that work practice standards 
associated with these requirements--e.g., maintaining openings in a 
closed

[[Page 49124]]

position except as necessary for access; conducting filling/emptying as 
rapidly as possible--are considered to be acceptable mechanisms to 
minimize overall emissions from these types of equipment, even when 
they do not limit emissions at all during a few brief periods that are 
necessary for operational or safety reasons.
    Response: We disagree with the comment that the work practice 
standards that we are finalizing for PRD releases and for emergency 
releases from flares are malfunction exemptions and we disagree with 
the assertion that the standards do not apply at all times. We also 
disagree that PRDs are simply bypasses for emissions that are subject 
to emission limits and controls or that they allow for uncontrolled 
emissions without violation or penalty. We also disagree that the 
standards being finalized allow facilities to ignore the flare tip 
velocity and no-visible emissions flare requirements such that a flare 
can smoke without repercussions and without limits repeatedly.
    As discussed in section IV.C of this preamble, the requirements and 
work practice standards require a number of prevention measures that 
operators must undertake to prevent PRD release and flare smoking 
events, including the installation and operation of continuous 
monitoring device(s) to identify when a PRD release has occurred. The 
work practice combustion efficiency standards (specifically limits on 
the NHVcz) and requirements to have a continuously lit pilot flame or 
flare flame apply at all times, including during periods of emergency 
flaring. We also note that a flare is not a specific emission source 
within the MON standards; rather, a flare is an APCD that has always 
been a type of emission control technology that miscellaneous organic 
chemical manufacturing facilities could utilize to comply with the 
underlying MACT standards. Flares are associated with a wide variety of 
process equipment, and the emissions routed to a flare during a 
malfunction can vary widely based on the cause of the malfunction and 
the type of associated equipment. As such, there can be certain 
instances when flares may be operated above their smokeless capacity to 
control emissions from certain events such as malfunction events, and 
we are finalizing work practice standards for visible emissions events 
when flares are operated above their smokeless capacity based on the 
best performing flares in the source category.
    Further, we are limiting the number of releases that would result 
in a deviation from the work practice standards. Regarding the comment 
that civil penalties may provide remedy for these releases, we note 
that the work practice standards provide for sufficient specificity to 
identify when a release is a deviation from the work practice standard, 
as well as a root cause analysis to help guide a decisionmaker in 
deciding whether to pursue an enforcement action because they believe a 
violation has occurred and for a court or other arbiter to rule on any 
claim.
4. What is the rationale for our final approach and final decisions to 
address emissions during periods of SSM?
    We evaluated all of the comments on the EPA's proposed amendments 
to the SSM provisions. For the reasons explained in the proposed rule 
(84 FR 69182, December 17, 2019), we determined that these amendments, 
which remove and revise provisions related to SSM, are necessary to be 
consistent with the requirement that the standards apply at all times. 
More information concerning the amendments we are finalizing for SSM is 
in the preamble to the proposed rule and in the comments and our 
specific responses to the comments in the document, Summary of Public 
Comments and Responses for the Risk and Technology Review for 
Miscellaneous Organic Chemical Manufacturing, available in the docket 
for this rulemaking. Therefore, we are finalizing our approach for the 
SSM provisions as proposed.

E. Other Amendments to the MACT Standards

1. What other amendments did we propose for the Miscellaneous Organic 
Chemical Manufacturing source category?
    We proposed adding monitoring requirements at 40 CFR 63.2450(e)(7) 
for adsorbers that cannot be regenerated and regenerative adsorbers 
that are regenerated offsite because the MON does not currently include 
specific monitoring requirements for this type of APCD. We proposed 
that owners or operators of this type of APCD use dual adsorbent beds 
in series and conduct daily monitoring. In order to monitor performance 
deterioration, we proposed daily measurements of HAP or TOC using a 
portable analyzer or chromatographic analysis for non-regenerative 
adsorbers (to be taken daily on the outlet of the first adsorber bed in 
series using a sample port). Furthermore, in order to relieve some 
monitoring burden, we proposed an option to reduce the frequency of 
monitoring with the portable analyzer from daily to weekly or monthly.
    We also proposed that owners or operators submit electronic copies 
of required flare management plans (at 40 CFR 63.2450(e)(5)(iv)), 
compliance reports (at 40 CFR 63.2520(e)), performance test reports (at 
40 CFR 63.2520(f)), and performance evaluation reports (at 40 CFR 
63.2520(g)) through the EPA's CDX using CEDRI, and we proposed two 
narrow circumstances in which owners or operators may seek extensions 
to the deadline if they are prevented from reporting by conditions 
outside of their control within five business days of the reporting 
deadline. We proposed at 40 CFR 63.2520(h) that an extension may be 
warranted due to outages of the EPA's CDX or CEDRI that precludes an 
owner or operator from accessing the system and submitting required 
reports. We also proposed at 40 CFR 63.2520(i) that an extension may be 
warranted due to a force majeure event, such as an act of nature, act 
of war or terrorism, or equipment failure or safety hazards beyond the 
control of the facility.
    Finally, we proposed revisions to clarify text or correct 
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.
2. How did the other amendments for the Miscellaneous Organic Chemical 
Manufacturing source category change since proposal?
    We are finalizing the other amendments discussed in section IV.E.1 
of this preamble as proposed, except that, 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 
three years after date of publication of final rule in the Federal 
Register or once the reporting template has been available on the CEDRI 
website for 1 year, whichever date is later. Also, as discussed further 
in the response to comment document for this rulemaking, we are adding 
back in provisions originating from 40 CFR 63.104(a)(1), (2), (5), and 
(6) that were inadvertently removed in the proposed rule. Finally, we 
are including several additional minor clarifying edits in the final 
rule based on comments received during the public comment period.
    We are revising the proposed monitoring requirements at 40 CFR 
63.2450(e)(7) for adsorbers that cannot be regenerated and regenerative

[[Page 49125]]

adsorbers that are regenerated offsite to reduce the frequency of 
monitoring with the portable analyzer based upon the design life of the 
bed. Instead of daily monitoring, the final rule will allow owners or 
operators to monitor monthly if the bed has at least two months of the 
bed design life remaining and weekly if the bed has between two months 
and two weeks of bed design life remaining. Daily monitoring is 
required once the bed has less than two weeks of bed design life 
remaining. Under the final rule, owners or operators will also be 
required to conduct monitoring no later than 3 days after a bed is put 
into service as the first bed to confirm that it is functioning 
properly.
3. What key comments did we receive on the other amendments for the 
Miscellaneous Organic Chemical Manufacturing source category and what 
are our responses?
    This section provides comment and responses for the key comments 
received regarding our proposed revisions to the monitoring 
requirements for adsorbers that cannot be regenerated and regenerative 
adsorbers that are regenerated offsite. With the exception of these 
comments related to the proposed monitoring requirements for adsorbers, 
we did not receive many substantive comments on the other amendments in 
the MON RTR proposal. The comments we received regarding other 
amendments generally include issues related to electronic reporting, 
removal of certain exemptions for heat exchange systems, overlap 
provisions for equipment leaks, and revisions that we proposed for 
clarifying text or correcting typographical errors, grammatical errors, 
and cross-reference errors. The comments and our specific responses to 
these issues 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.
    Comment: Several commenters disagreed with the proposed requirement 
at 40 CFR 63.2450(e)(7) for adsorbers that cannot be regenerated or 
adsorbers that are regenerated offsite.
    Commenters contended that requiring the addition of a second 
adsorber bed in series is not a monitoring function but is a change in 
allowed controls and, therefore, is an equipment standard that must be 
evaluated under CAA section 112(d)(6).
    Commenters disagreed with the EPA's justification for requiring a 
dual bed system as ``use of a single bed does not ensure continuous 
compliance unless the bed is replaced significantly before 
breakthrough,'' (84 FR 69227) arguing that (1) This same argument also 
applies to dual bed systems, and (2) the EPA makes no claim that use of 
a single bed is not achieving continuous compliance frequently enough 
to justify disallowing single bed systems. Commenters stated that 
facilities typically follow conservative single-bed change procedures 
(e.g., 20 to 30 percent of bed saturation) and that single beds are 
typically oversized and used where only a small percentage of their 
capacity is expected to be needed. Commenters asserted that 
conservative single bed change decisions reduce the monitoring required 
in such cases under applicable rules or permits, or a very conservative 
breakthrough point is set by rule or permit. Commenter noted that if 
owners or operators replace single beds prematurely and the cost of the 
replacement bed is small compared to the increased compliance 
assurance, then early replacement should be the preferred approach for 
assuring compliance, because it avoids all of the costs and emissions 
associated with having dual beds and results in a larger margin of 
compliance assurance than for a dual bed installation.
    Commenter claimed that adding piping components required for a dual 
bed system will have negative consequences: (1) Adding continuous 
fugitive emissions from the additional valves and connectors, and (2) 
creating, in some cases, operating concerns or requiring addition of 
compression due to the added back pressure from the second bed.
    Commenters contended that the proposed equipment standard is not 
cost effective and would not achieve any reduction in emissions. 
Commenters disagreed with the EPA's position that there would be no 
cost for a second bed in a dual bed system and argued that the EPA did 
not consider the cost of design and engineering, additional structural 
elements and foundations, reconfiguring the piping, adding valves to 
isolate each bed, and relocating existing single beds where space is 
not available for a second bed.
    Commenters recommended that the EPA not require dual adsorber beds 
and monitoring for temporary adsorbers (e.g., systems used for less 
than 6 months) and small adsorbers that infrequently need replacement. 
Commenters stated that the only requirement for such systems should be 
a record demonstrating the bed life is appropriate for the maximum 
expected emissions loading. Commenter recommended that small adsorbers 
that are operated solely as back-up control devices should also be 
exempted on the basis of the requirements not being cost effective, and 
on the basis that they are operated no more than some percentage of the 
minimum potential saturation time.
    Commenters asserted that 3 years would be needed to comply with 
this proposed requirement because the retrofit of an existing single 
bed system will have to be engineered, appropriated, and then designed 
and constructed.
    Commenters requested that, if the EPA promulgates the adsorber 
monitoring requirements, the EPA should also remove the requirement at 
40 CFR 63.2450(e)(7)(iii)(B) to conduct daily monitoring for the first 
three adsorber bed change outs because this amount of testing is 
excessive and represents an unnecessary cost. Commenters stated that, 
to ensure compliance, some facilities routinely replace adsorbent well 
in advance of breakthrough. For example, on a non-continuous/
intermittent backup system, commenters stated that some facilities 
replace adsorbent on a yearly basis, regardless of whether the bed is 
approaching saturation, and bed life would never be established as 
proposed. In other cases, commenters stated that bed life may be 
several months, and daily monitoring would be unnecessarily expensive. 
Commenters recommended that the EPA adopt a reduced monitoring 
frequency similar to the Benzene Waste Operations NESHAP at 40 CFR 
61.354(d) where facilities are allowed to monitor either daily or at 
intervals no greater than 20 percent of the design carbon replacement 
interval.
    Commenters also requested the use of colorimetric tubes to monitor 
for breakthrough in place of instrument monitoring. These tubes are 
placed in a fitting in the vent at the outlet of the first adsorber bed 
and are filled with a reagent that changes color when exposed to 
specific target compounds or to volatile organic compounds, depending 
on the vapor, which indicates breakthrough.
    Finally, commenters requested that the EPA clarify that systems 
with more than two adsorber beds in series would be allowed and that 
dual bed (i.e., two bed) systems are not the only ones allowed.
    Response: The EPA is revising the proposed monitoring requirements 
for non-regenerative adsorbers to address some of the commenters 
concerns, but the final rule still requires the use of a dual bed 
system in series and monitoring at the outlet of the first bed to 
detect breakthrough.

[[Page 49126]]

    The EPA acknowledges that the proposed requirements could have been 
considered under CAA section 112(d)(6) because of the specification to 
have two adsorber beds in series, instead of as a proposed change to 
the monitoring requirements. However, the EPA presented the technical 
rationale for why a second bed was needed and for why the estimated 
costs for adding a second bed would be minimal. This rationale would 
not have been any different if the EPA described the proposed changes 
under CAA section 112(d)(6) instead of as a monitoring change. These 
changes were proposed because the current 40 CFR part 63, subpart FFFF, 
contained no monitoring requirements for non-regenerative adsorbers.
    The commenters requested that the EPA establish work practice or 
operational standards that would allow the continued use of a single 
bed system (e.g., changing adsorber beds when they had reached some 
percentage of their designed capacity). While we agree with the comment 
that a single bed approach can be very effective at controlling HAP 
from sources subject to the MON, our goal is to ensure that sources are 
complying with the standards at all times and even a well maintained 
single bed system is vulnerable to errors that are not possible with 
the dual bed system we are requiring. The proposed and final monitoring 
requirements for non-regenerative adsorbers fulfill the EPA's 
obligation to establish monitoring requirements to ensure continuous 
compliance with the emission limits (e.g., 98-percent control or a 20 
ppm TOC outlet concentration) when owners or operators are using these 
types of control devices to comply with the standards.
    In response to the commenters' concerns about the costs of adding a 
second adsorber bed, we used the EPA's cost algorithms to estimate the 
cost of a second carbon adsorber bed for two adsorber scenarios. In the 
first, scenario, the EPA estimated the cost of a replaceable-canister 
type adsorber holding 180 lbs of carbon. The total capital investment 
of the second bed (including installation and auxiliary equipment) is 
about $5,100, and the total annual cost is about $900. In the second 
scenario, we estimated the cost of an adsorber that holds 3,000 lbs of 
carbon and in which the carbon is removed and replaced by fresh carbon 
when needed. The total capital investment of the second bed (including 
installation and auxiliary equipment) is about $22,300, and the total 
annual cost is about $3,000. We assumed no additional labor would be 
required for operation and maintenance of the second adsorber bed 
compared to operating and maintaining a single bed adsorber. We 
documented this analysis for the final rulemaking in the memorandum, 
Analysis of Monitoring Costs and Dual Bed Costs for Non-Regenerative 
Carbon Adsorbers Used in the Miscellaneous Organic Chemical 
Manufacturing Source Category For the Final Rule, which is available in 
the docket for this rulemaking.
    In both scenarios, we assumed that the first bed would be replaced 
when it reached breakthrough (i.e., its equilibrium capacity, which is 
when the adsorption zone of the bed reaches the bed outlet and the 
volatile concentration in the exhaust begins to rise) based on 
monitoring at the outlet of the first bed. At that time, the owner or 
operator would divert the flow from the first to the second bed, the 
canisters or carbon would be replaced in the first bed, and it would 
then be returned to service as the second bed in the series. We did not 
include the cost of replacing the canisters or the carbon in the annual 
costs because the amount of carbon used would not increase as a result 
of using a second bed in series. The EPA still concludes that having 
two beds in series and performing monitoring at the outlet of the first 
bed will reduce the amount of adsorber media (e.g., activated carbon) 
used by facilities because they will not have to replace the adsorber 
media until it reaches equilibrium capacity. With only a single bed and 
no monitoring, facilities need to replace the adsorber media more 
frequently based on the estimated working capacity of the bed (which is 
a fraction of the equilibrium capacity) so as to maintain compliance 
and to avoid exceeding outlet concentration limits. The EPA determined 
at proposal that the use of two beds in series and the use of 
monitoring will maximize the life of each bed and reduce adsorber media 
replacement costs. The EPA has not changed that determination based on 
the public comments submitted or on the analyses completed since 
proposal.
    The EPA is revising the proposed monitoring requirements to reduce 
the frequency of monitoring. In the final rule, owners or operators 
will be able to conduct monitoring based on the design life of the 
adsorber bed. The final monitoring requirements are similar to what the 
EPA proposed for owners or operators who establish the life of the 
adsorber bed based on at least three bed replacement cycles. However, 
in the final rule, the EPA will allow owners or operators to use the 
design life of the bed and to monitor monthly if the bed has at least 
two months of the bed design life remaining and weekly if the bed has 
between two months and two weeks of bed design life remaining. Once the 
remaining bed design life reaches two weeks, daily monitoring is 
required. This change from proposal will not lead to an increase in 
emissions because the final rule will still require the use of beds in 
series, and any emissions detected when the first bed reaches 
breakthrough will still be captured by the second bed in the series. 
After breakthrough on the first bed is detected, the first bed will be 
removed from service and replaced. The second bed will be moved to the 
first bed position and the newly replaced bed will become the second 
bed in series. Therefore, the newest bed will always be operated as a 
backup to the older bed. Under the final rule, owners or operators will 
also be required to conduct monitoring no later than 3 days after a bed 
is put into service as the first bed to confirm that it is functioning 
properly. This change will substantially reduce the cost of monitoring. 
For example, the capital cost of portable FID was estimated to be 
$9,000, and the total annual cost for daily monitoring was estimated to 
be $13,000, but the total annual cost for monthly and weekly monitoring 
were estimated to be $2,600 and $3,700, respectively.
    We did not estimate the cost effectiveness (i.e., the cost per ton 
of HAP reduced) of requiring the second adsorber bed and the final 
monitoring requirements because the second bed is acting as a backup to 
the first bed to capture any potential breakthrough, and it is 
difficult to estimate the mass of HAP that will be captured and the 
excess emissions that will be avoided by the monitoring.
    The EPA is not including an exemption from the final rule 
requirements for adsorbers used for temporary applications or as backup 
for other control devices. Control devices used to comply with an 
emission limitation, even on a temporary basis, must still meet the 
same performance and monitoring requirements as one used on a permanent 
basis.
    In the final rule, the EPA is not allowing the use of colorimetric 
tubes in place of instrument monitoring at the outlet of the first 
adsorber bed. The EPA investigated the use of these tubes but could not 
find any specification or quality assurance standard that could be 
incorporated by reference to ensure the accuracy of these tubes in 
detecting breakthrough. Additionally, we could not find information on 
the material contained within the tubes and whether the material would 
react with all HAP being controlled by adsorbers in the

[[Page 49127]]

Miscellaneous Organic Chemical Manufacturing source category.
    Finally, the EPA is clarifying in the final rule, in response to 
comments, that systems with at least two beds are required, but systems 
with more than two beds in series are allowed.
4. What is the rationale for our final approach and final decisions for 
the other amendments for the Miscellaneous Organic Chemical 
Manufacturing source category?
    Based on the comments received for these other amendments, we are 
generally finalizing all proposed requirements, with the exception of 
the monitoring requirements for adsorbers that cannot be regenerated or 
adsorbers that are regenerated offsite. For the reasons described in 
section IV.E.3 of this preamble, we are revising the proposed 
monitoring requirements for these adsorbers in the final rule to reduce 
the monitoring frequency from what we proposed.
    In a few instances (e.g., overlap provisions for equipment leaks), 
we received comments that led to additional minor editorial corrections 
and technical clarifications being made in the final rule, and our 
rationale for these corrections and technical clarifications can be 
found in the document, Summary of Public Comments and Responses for the 
Risk and Technology Review for Miscellaneous Organic Chemical 
Manufacturing, available in the docket for this rulemaking.

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

A. What are the affected facilities?

    We estimate that, as of November 6, 2018, there were 201 MON 
facilities. 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).

B. What are the air quality impacts?

    At the current level of control prior to the amendments being 
finalized in this action, the EPA estimates that ethylene oxide 
emissions were approximately 1.1 tpy (actuals) and 3.1 tpy (allowables) 
from the eight MON facilities with emission process groups (i.e., 
process vents, storage tanks, equipment leaks) in ethylene oxide 
service. At the level of control required by the amendments being 
finalized in this action, which includes amendments to process vents, 
storage tanks, and equipment in ethylene oxide service (equipment leak 
Control Option 1), we estimated ethylene oxide emissions reductions of 
0.76 tpy (actuals) and 2.7 tpy (allowables) for the source category.
    At the level of control prior to the amendments being finalized in 
this action, we estimated HAP emissions for all MON facilities of 
approximately 7,420 tpy and VOC emissions of approximately 19,720 tpy, 
based on emissions from the MON modeling file available for 194 of the 
201 MON facilities identified in this rulemaking. Note that seven of 
the 201 MON facilities did not report HAP emissions to the 2014 NEI for 
MON processes. Of this total, approximately 2,558 tpy of HAP and 6,730 
tpy of VOC are attributed to emission process groups with amendments 
being finalized in this action. At the level of control required by the 
amendments being finalized in this action, we estimate HAP emissions 
reductions between 107 tpy and 130 tpy and VOC emissions reductions 
between 283 tpy and 532 tpy. As discussed in the proposal preamble (84 
FR 69182, December 17, 2019), we estimated HAP emissions using two 
different methods (i.e., based on the MON emission inventory and based 
on model plants, respectively), so estimated emission reductions are 
presented as a range. We also estimate excess emissions reductions from 
flares that could result from the final monitoring requirements, which 
we estimate to be 263 tpy HAP and 1,254 tpy VOC. When considering the 
flare excess emissions, the total emissions reductions as a result of 
the final amendments are estimated to be between 370 and 393 tpy of HAP 
and between 1,537 and 1,786 tpy of VOC. These emissions reductions are 
documented in the following memoranda, which are available in the 
docket for this rulemaking: Clean Air Act Section 112(d)(6) Technology 
Review for Equipment Leaks Located in the Miscellaneous Organic 
Chemical Manufacturing Source Category For the Final Rule, Clean Air 
Act Section 112(d)(6) Technology Review for Heat Exchange Systems 
Located in the Miscellaneous Organic Chemical Manufacturing Source 
Category For the Final Rule, Analysis of Control Options for Storage 
Tanks and Process Vents Emitting Ethylene Oxide Located in the 
Miscellaneous Organic Chemical Manufacturing Source Category For the 
Final Rule, Analysis of Control Options for Equipment Leaks at 
Processes that use Ethylene Oxide Located in the Miscellaneous Organic 
Chemical Manufacturing Source Category For the Final Rule, Control 
Option Impacts for Flares Located in the Miscellaneous Organic Chemical 
Manufacturing Source Category, and Residual Risk Assessment for the 
Miscellaneous Organic Chemical Manufacturing Source Category in Support 
of the 2020 Risk and Technology Review Final Rule.

C. What are the cost impacts?

    The total capital investment cost of the final amendments and 
standards is estimated at approximately $43 million, including 
approximately $40 million for MON facilities without ethylene oxide 
controls and $3 million from MON facilities with ethylene oxide 
controls. We estimate total annual costs of the final amendments, 
without recovery credits, to be approximately $13 million.
    The nationwide costs of the amendments being finalized in this 
action are presented in Table 5 of this preamble for (1) All MON 
sources, (2) only MON sources not expected to be affected by the 
ethylene oxide-specific controls being finalized in this action (i.e., 
equipment leaks, heat exchange systems, flares, PRDs, maintenance 
vents, storage tank degassing activities, recordkeeping and reporting), 
and (3) only MON sources expected to be affected by the ethylene oxide 
controls being finalized in this action (i.e., storage tanks, process 
vents, equipment leaks). As described in this preamble, for ethylene 
oxide sources, we are finalizing amendments for storage tanks and 
process vents in ethylene oxide service. For equipment in ethylene 
oxide service, of the two co-proposed options we are finalizing 
equipment leak co-proposed Control Option 1, which requires that the 
same equipment leak standards (i.e., lower the leak definition for 
batch pumps to 1,000 ppm and require connector monitoring at a leak 
definition of 500 ppm) will apply to all facilities in ethylene oxide 
service. These costs are presented in Table 5 of this preamble. There 
are 201 facilities affected by the amendments, and the number of 
facilities affected by each of the specific amendments is indicated in 
Table 5 below. The facility list 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 2020 
Risk and Technology Review Final Rule, which is

[[Page 49128]]

available in the docket for this rulemaking.

                            Table 5--Total Capital Investment and Total Annual Costs
                                                     [2016$]
----------------------------------------------------------------------------------------------------------------
                                                     Number of
                                                  facilities  w/                   Total annual    Total annual
                                                       costs       Total capital     costs w/o       costs  w/
                                                    associated      investment       recovery        recovery
                                                     with new                         credits         credits
                                                   requirements
----------------------------------------------------------------------------------------------------------------
    All MON Sources--Total......................  ..............      42,700,000      12,700,000      12,300,000
----------------------------------------------------------------------------------------------------------------
    MON Sources w/o Ethylene Oxide Controls--     ..............      39,700,000      11,400,000      11,100,000
     Total......................................
                                                 ---------------------------------------------------------------
Flares \1\......................................              21      17,200,000       4,090,000       4,090,000
Equipment Leaks \2\.............................             193         829,000         150,000          81,800
PRDs \3\........................................             201      18,700,000       4,770,000       4,770,000
Maintenance Vents \3\...........................             201  ..............           2,340           2,340
Heat Exchange Systems \4\.......................             201       1,480,000         261,000        (14,300)
Degassing Tanks \5\.............................             162  ..............         489,000         489,000
Recordkeeping and Reporting.....................             201       1,490,000       1,650,000       1,650,000
----------------------------------------------------------------------------------------------------------------
    MON Sources w/Ethylene Oxide Controls--Total  ..............       2,990,000       1,250,000       1,250,000
                                                 ---------------------------------------------------------------
Equipment Leaks \6\.............................               7          71,100          47,500          44,600
Process Vents \7\...............................               3       2,740,000         943,000         943,000
Storage Tanks \7\...............................               3         178,000         258,000         258,000
----------------------------------------------------------------------------------------------------------------
Costs are rounded to three significant figures.
\1\ The flare costs include purchasing analyzers, monitors, natural gas and steam, developing a flare management
  plan, and performing root cause analysis and corrective action, and are discussed in the memorandum, Control
  Option Impacts for Flares Located in the Miscellaneous Organic Chemical Manufacturing Source Category, which
  is available in the docket for this rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-0006).
\2\ Equipment leak costs include LDAR at a leak definition of 1,000 ppmv for light liquid pumps at batch
  processes, and are discussed in the memoranda, Clean Air Act Section 112(d)(6) Technology Review for Equipment
  Leaks Located in the Miscellaneous Organic Chemical Manufacturing Source Category (see Docket Item No. EPA-HQ-
  OAR-2018-0746-0003) and Clean Air Act Section 112(d)(6) Technology Review for Equipment Leaks Located in the
  Miscellaneous Organic Chemical Manufacturing Source Category For the Final Rule which are available in the
  docket for this rulemaking.
\3\ PRD costs were developed to comply with the work practice standard being finalized in this action and
  include implementation of three prevention measures, performing root cause analysis and corrective action, and
  purchasing PRD monitors. Maintenance costs were estimated to document equipment opening procedures and
  circumstances under which the alternative maintenance vent limit is used. Costs are discussed in the
  memorandum, Review of Regulatory Alternatives for Certain Vent Streams in the Miscellaneous Organic Chemical
  Manufacturing Source Category, which is available in the docket for this rulemaking (see Docket Item No. EPA-
  HQ-OAR-2018-0746-0010).
\4\ Heat exchange systems costs include the use of the Modified El Paso Method to monitor for leaks, and are
  discussed in the memoranda, Clean Air Act Section 112(d)(6) Technology Review for Heat Exchange Systems
  Located in the Miscellaneous Organic Chemical Manufacturing Source Category (see Docket Item No. EPA-HQ-OAR-
  2018-0746-0007) and Clean Air Act Section 112(d)(6) Technology Review for Heat Exchange Systems in the
  Miscellaneous Organic Chemical Manufacturing Source Category For the Final Rule, which are available in the
  docket for this rulemaking.
\5\ Costs for degassing storage tanks are discussed in the memorandum, Storage Tank Degassing Cost and Emissions
  Impacts for the Miscellaneous Organic Chemical Manufacturing Source Category For the Final Rule, which is
  available in the docket for this rulemaking.
\6\ Equipment leak costs for equipment in ethylene oxide service include costs for equipment leak co-proposed
  Control Option 1. Control Option 1 includes LDAR at a leak definition of 1,000 ppmv for light liquid pumps at
  batch processes with monthly monitoring and connector monitoring at a leak definition of 500 ppmv with annual
  monitoring. Costs are discussed in the memoranda, Analysis of Control Options for Equipment Leaks at Processes
  that use Ethylene Oxide Located in the Miscellaneous Organic Chemical Manufacturing Source Category (see
  Docket Item No. EPA-HQ-OAR-2018-0746-0004) and Analysis of Control Options for Equipment Leaks at Processes
  that use Ethylene Oxide Located in the Miscellaneous Organic Chemical Manufacturing Source Category For the
  Final Rule, which are available in the docket for this rulemaking.
\7\ Costs for process vents and storage tanks in ethylene oxide service include the requirement to control all
  storage tanks in ethylene oxide service, the installation of a control device that achieves 99.9-percent
  ethylene oxide emissions reductions, and initial and periodic performance testing of the control device, and
  are discussed in the memoranda, Analysis of Control Options for Storage Tanks and Process Vents Emitting
  Ethylene Oxide Located in the Miscellaneous Organic Chemical Manufacturing Source Category (see Docket Item
  No. EPA-HQ-OAR-2018-0746-0005) and Analysis of Control Options for Storage Tanks and Process Vents Emitting
  Ethylene Oxide Located in the Miscellaneous Organic Chemical Manufacturing Source Category For the Final Rule,
  which are available in the docket for this rulemaking.

D. What are the economic impacts?

    The economic impact analysis is designed to inform decision makers 
about the potential economic consequences of the compliance costs 
outlined in section V.C of this preamble. The EPA performed a screening 
analysis for impacts on all affected facilities by comparing compliance 
costs to revenues at the ultimate parent company level. This is known 
as the cost-to-revenue or cost-to-sales test, or the ``sales test.'' 
The ``sales test'' is an impact methodology the EPA employs in 
analyzing entity impacts as opposed to a ``profits test,'' in which 
annualized compliance costs are calculated as a share of profits. The 
use of a sales test for estimating small business impacts for a 
rulemaking is consistent with guidance offered by the EPA on compliance 
with the Regulatory Flexibility Act (RFA) and is consistent with 
guidance published by the U.S. Small Business Administration's Office 
of Advocacy that suggests that cost as a percentage of total revenues 
is a metric for evaluating cost increases on small entities in relation 
to increases on large entities.
    There are 201 MON facilities, owned by 99 parent companies, 
affected by the final amendments. Of the parent companies, 17 
companies, or 17

[[Page 49129]]

percent, are small entities. We identified the North American Industry 
Classification System (NAICS) code for all parent companies and applied 
the U.S. Small Business Administration's table of size standards to 
determine which of the companies were small entities. Also, we 
calculated the cost-to-sales ratios for all the affected entities to 
determine (1) The magnitude of the costs of the amendments being 
finalized in this action and (2) whether there would be a significant 
impact on small entities. To be conservative, we used facility-specific 
costs without recovery credits. For all firms, the average cost-to-
sales ratio is approximately 0.06 percent; the median cost-to-sales 
ratio is less than 0.01 percent; and the maximum cost-to-sales ratio is 
approximately 0.97 percent. For large firms, the average cost-to-sales 
ratio is approximately 0.01 percent; the median cost-to-sales ratio is 
less than 0.01 percent; and the maximum cost-to-sales ratio is 
approximately 0.52 percent. For small firms, the average cost-to-sales 
ratio is approximately 0.30 percent, the median cost-to-sales ratio is 
0.11 percent, and the maximum cost-to-sales ratio is 0.97 percent. The 
facility-specific costs for the 17 small firms ranged from $35,083 to 
$42,746 annually (2016$). The costs of the final action are not 
expected to result in a significant market impact, regardless of 
whether they are passed on to the purchaser or absorbed by the firms.
    More information and details of this analysis is provided in the 
memorandum, Economic Impact and Small Business Screening Assessments 
for Final Amendments to the National Emission Standards for Hazardous 
Air Pollutants: Miscellaneous Organic Chemical Manufacturing, which is 
available in the docket for this rulemaking.

E. What are the benefits?

    The EPA did not monetize the benefits from the estimated emission 
reductions of HAP associated with this final action. The EPA currently 
does not have sufficient methods to monetize benefits associated with 
HAP, HAP reductions, and risk reductions for this rulemaking. However, 
we estimate that the final rule amendments would reduce HAP emissions 
by 107 tons per year and thus lower risk of adverse health effects in 
communities near facilities subject to the MON.

F. What analysis of environmental justice did we conduct?

    Executive Order 12898 (59 FR 7629, February 16, 1994) establishes 
Federal executive policy on environmental justice. Its main provision 
directs Federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    To examine the potential for any environmental justice issues that 
might be associated with the source category, we performed a 
demographic analysis, which is an assessment of risks to individual 
demographic groups of the populations living within 5 km and within 50 
km of the facilities. In the analysis, we evaluated the distribution of 
HAP-related cancer and noncancer risks from the Miscellaneous Organic 
Chemical Manufacturing source category across different demographic 
groups within the populations living near facilities.
    Our analysis of the demographics of the population with estimated 
risks greater than 1-in-1 million indicates potential disparities in 
risks between demographic groups, including the African American, 
Hispanic or Latino, Over 25 Without a High School Diploma, and Below 
the Poverty Level groups. In addition, the population living within 50 
km of the MON facilities has a higher percentage of minority, lower 
income, and lower education people when compared to the nationwide 
percentages of those groups. However, acknowledging these potential 
disparities, the risks for the source category were determined to be 
acceptable after implementation of the controls required by the final 
amendments, and emissions reductions from the final amendments will 
benefit these groups the most.
    The documentation for this decision is contained in section IV.A of 
this preamble, and the technical report, Risk and Technology Review--
Analysis of Demographic Factors for Populations Living Near 
Miscellaneous Organic Chemical Manufacturing Source Category Operations 
dated November 27, 2018, which is available in the docket for this 
rulemaking.
    As noted in section IV, the EPA reanalyzed risks using emission 
inventory updates from a CAA section 114 request and additional 
information received during the public comment period. Based on the 
revised risk results, the EPA also updated the demographic analysis. 
The revised demographic analysis indicated slight changes (ranging from 
1-3%) in the population with estimated risks greater than 1-in-1 
million for four demographic groups (African American, Hispanic or 
Latino, Below the Poverty Level, and Linguistic Isolation). However, 
the overall conclusions remain the same. The updated demographic 
analysis, Risk and Technology Review--Analysis of Demographic Factors 
for Populations Living Near Miscellaneous Organic Chemical 
Manufacturing Source Category Operations dated May 21, 2020, is 
available in the docket for this rulemaking.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children. This action's health and risk assessments are summarized in 
section IV.A of this preamble and are further documented in the risk 
report, 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 (see Docket Item No. EPA-HQ-OAR-2018-0746-0013).

VI. Statutory and Executive Order Reviews

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

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

    This action is a significant regulatory action that was submitted 
to Office of Management and Budget (OMB) for review because it raises 
novel legal or policy issues. Any changes made in response to OMB 
recommendations have been documented in the docket. The EPA prepared an 
analysis of the potential costs and benefits associated with this 
action. This analysis is found in the memorandum Economic Impact and 
Small Business Screening Assessments for Final Amendments to the 
National Emission Standards for Hazardous Air Pollutants: Miscellaneous 
Organic Chemical Manufacturing, in the docket for this rulemaking.

[[Page 49130]]

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

    This action is considered an Executive Order 13771 regulatory 
action. Details on the estimated costs of this final rule can be found 
in the EPA's analysis of the potential costs and benefits associated 
with this action discussed in section V of this preamble.

C. Paperwork Reduction Act (PRA)

    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The Information Collection 
Request (ICR) document that the EPA prepared has been assigned EPA ICR 
number 1969.09. You can find a copy of the ICR in the docket for this 
rule, and it is briefly summarized here. The information collection 
requirements are not enforceable until OMB approves them.
    We are finalizing amendments that change the reporting and 
recordkeeping requirements for several emission sources at MON 
facilities (e.g., flares, heat exchangers, PRDs, storage tanks, and 
process vents). Specifically, we are finalizing, as proposed, a 
requirement that owners or operators of MON facilities submit 
electronic copies of notification of compliance status reports (being 
finalized at 40 CFR 63.2520(d)), 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 CDX using the CEDRI. We are also 
requiring recordkeeping of each report and other records for storage 
tank degassing, flares, PRDs, process vents, storage tanks, heat 
exchangers, bypass lines, and maintenance vents (being finalized at 40 
CFR 63.2470(f), and 40 CFR 63.2525(m) through (r)). The final 
amendments also remove the malfunction exemption and impose other 
revisions that affect reporting and recordkeeping.
    This information will be collected to assure compliance with 40 CFR 
part 63, subpart FFFF. The total estimated burden and cost for 
reporting and recordkeeping due to these amendments are presented below 
and are not intended to be cumulative estimates that include the burden 
associated with the requirements of the existing 40 CFR part 63, 
subpart FFFF.
    Respondents/affected entities: Owners or operators of MON 
facilities.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart FFFF).
    Estimated number of respondents: 201 (total).
    Frequency of response: Semiannual or annual. Responses include 
notification of compliance status reports and semiannual compliance 
reports.
    Total estimated burden: 12,219 hours (per year). Burden is defined 
at 5 CFR 1320.3(b).
    Total estimated cost: $3,642,730 (per year), includes $2,405,799 
annualized capital and operation and maintenance costs.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities in this final rule.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. The 
small entities subject to the requirements of this action are small 
businesses according to the Small Business Administration's small 
business size standards. The Agency has determined that 17 of the 99 
affected entities are small entities that may experience an impact of 
an average cost-to-sales ratio of approximately 0.30 percent. Details 
of this analysis are presented in the memorandum, Economic Impact and 
Small Business Screening Assessments for Final Amendments to the 
National Emission Standards for Hazardous Air Pollutants: Miscellaneous 
Organic Chemical Manufacturing, which is available in the docket for 
this rulemaking.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. While this action 
creates an enforceable duty on the private sector, the cost does not 
exceed $100 million or more.

F. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the National Government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

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

    This action does not have tribal implications as specified in 
Executive Order 13175. None of the MON facilities that have been 
identified as being affected by this final action are owned or operated 
by tribal governments or located within tribal lands within a 10 mile 
radius. Thus, Executive Order 13175 does not apply to this action. We 
conducted an impact analysis using the latitude and longitude 
coordinates from the risk modeling input file to identify tribal lands 
within a 10 and 50 mile radius of MON facilities to determine potential 
air quality impacts on tribes. Consistent with the EPA Policy on 
Consultation and Coordination with Indian Tribes, although there were 
no tribal lands located within a 10 mile radius of MON facilities, the 
EPA offered consultation with 14 tribes that were identified within a 
50 mile radius of an affected facility, however, no tribal officials 
requested consultation. Additional details regarding the consultation 
letter and distribution list can be found in the memorandum, MON RTR 
Consultation Letter, which is available in the docket for this 
rulemaking. The EPA also participated on a phone call with the National 
Tribal Air Association on December 12, 2019, and presented an overview 
of the rulemaking.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children. This action's health and risk assessments are contained in 
section IV.A of this preamble and further documented in the risk 
report, Residual Risk Assessment for the Miscellaneous Organic Chemical 
Manufacturing Source Category in Support of the 2020 Risk and 
Technology Review Final Rule, which is available in the docket for this 
rulemaking.

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

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. The overall energy consumption and

[[Page 49131]]

economic impact of these final amendments is expected to be minimal for 
MON facilities and their parent companies (some of which are engaged in 
the energy sector) and, therefore, we do not expect any adverse effects 
on the supply, distribution, or use of energy as a result.

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

    This rulemaking involves technical standards. As discussed in the 
proposal preamble (84 FR 69182, December 17, 2019), the EPA conducted 
searches for the MACT standards through the Enhanced National Standards 
Systems Network Database managed by the American National Standards 
Institute (ANSI). We also contacted voluntary consensus standards (VCS) 
organizations and accessed and searched their databases. We conducted 
searches for EPA Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 3, 3A, 3B, 4, 5, 
15, 18, 21, 22, 25, 25A, 25D, 26, 26A, and 29 of 40 CFR part 60, 
appendix A, 301, 305, 316, and 320 of 40 CFR part 63, 624 and 625 of 40 
CFR part 136, appendix A, 1624, 1625, 1666 and 1671 of 40 CFR part 136, 
appendix A, 5030B (SW-846), 5031, 8260, 8260B (SW-846), 8260D (SW-846), 
8270 and 8430 (SW-846) Test Methods for Evaluating Solid Waste, 
Physical/Chemical Methods, EPA Publication SW-846 third edition. During 
the EPA's VCS search, if the title or abstract (if provided) of the VCS 
described technical sampling and analytical procedures that are similar 
to the EPA's reference method, the EPA reviewed it as a potential 
equivalent method.
    The EPA incorporates by reference VCS ASTM D5790-95 (Reapproved 
2012), ``Standard Test Method for Measurement of Purgeable Organic 
Compounds in Water by Capillary Column Gas Chromatography/Mass 
Spectrometry,'' as an acceptable alternative to EPA Method 624 (and for 
the analysis of total organic HAP in wastewater samples). For 
wastewater analyses, this ASTM method should be used with the sampling 
procedures of EPA Method 25D or an equivalent method to be a complete 
alternative. The ASTM standard is validated for all of the 21 volatile 
organic HAP (including toluene) targeted by EPA Method 624 but is also 
validated for an additional 14 HAP not targeted by the EPA method. This 
test method covers the identification and simultaneous measurement of 
purgeable volatile organic compounds. This method is applicable to a 
wide range of organic compounds that have sufficiently high volatility 
and low water solubility to be efficiently removed from water samples 
using purge and trap procedures. We note that because the Cellulose 
Products Manufacturing RTR proposed rule has already proposed to revise 
the performance test requirements table (Table 4 to subpart UUUU of 
part 63) to add IBR for ASTM D5790-95 (Reapproved 2012) (see 84 FR 
47375, September 9, 2019), the EPA is not incorporating this specific 
aspect of this VCS by reference.
    The EPA incorporates by reference VCS ASTM D6420-18, ``Standard 
Test Method for Determination of Gaseous Organic Compounds by Direct 
Interface Gas Chromatography-Mass Spectrometry'' as an acceptable 
alternative to EPA Method 18 with the following caveats. This ASTM 
procedure has been approved by the EPA as an alternative to EPA Method 
18 only when the target compounds are all known and the target 
compounds are all listed in ASTM D6420-18 as measurable. ASTM D6420-18 
should not be used for methane and ethane because the atomic mass is 
less than 35; and ASTM D6420-18 should never be specified as a total 
VOC method. The ASTM D6420-18 test method employs a direct interface 
gas chromatograph-mass spectrometer to measure 36 VOC. The test method 
provides on-site analysis of extracted, unconditioned, and unsaturated 
(at the instrument) gas samples from stationary sources.
    The EPA incorporates by reference VCS ASTM D6784-02 (Reapproved 
2008), ``Standard Test Method for Elemental, Oxidized, Particle-Bound 
and Total Mercury Gas Generated from Coal-Fired Stationary Sources 
(Ontario Hydro Method),'' as an acceptable alternative to EPA Method 
101A of appendix B to 40 CFR part 61 and EPA Method 29 of appendix A-8 
to 40 CFR part 60 (portion for mercury only) as a method for measuring 
mercury. Note that this applies to concentrations of approximately 0.5 
to 100 micrograms per normal cubic meter of air. This method describes 
equipment and procedures for obtaining samples from effluent ducts and 
stacks, equipment and procedures for laboratory analysis, and 
procedures for calculating results. This method is applicable for 
sampling elemental, oxidized, and particle-bound mercury in flue gases 
of coal-fired stationary sources.
    The three ASTM methods (ASTM D5790-95 (Reapproved 2012), ASTM 
D6420-18, and ASTM D6784-02 (Reapproved 2008)) are available at ASTM 
International, 1850 M Street NW, Suite 1030, Washington, DC 20036. See 
https://www.astm.org/.
    While the EPA identified 23 other VCS as being potentially 
applicable, the Agency decided not to use them because these methods 
are impractical as alternatives because of the lack of equivalency, 
documentation, validation date, and other important technical and 
policy considerations. The search and review results have been 
documented and are in the memorandum, Voluntary Consensus Standard 
Results for National Emission Standards for Hazardous Air Pollutants: 
Miscellaneous Organic Chemical Manufacturing NESHAP RTR, which is 
available in the docket for this rulemaking (see Docket Item No. EPA-
HQ-OAR-2018-0746-0018).\26\
---------------------------------------------------------------------------

    \26\ At proposal, we identified two 40 CFR part 63, subpart SS, 
VCS (i.e., ANSI/ASME PTC 19-10-1981-Part 10 and ASTM D6348-12e1) 
that were also identified in the NTTAA review for the Ethylene 
Production RTR, and these VCS have already been finalized as 
amendments in that action (for further information, see Docket ID 
No. EPA-HQ-OAR-2017-0357 and 84 FR 54329, October 9, 2019).
---------------------------------------------------------------------------

    Under 40 CFR 63.7(f) and 40 CFR 63.8(f), subpart A--General 
Provisions, a source may apply to the EPA for permission to use 
alternative test methods or alternative monitoring requirements in 
place of any required testing methods, performance specifications, or 
procedures in the final rule or any amendments.
    Finally, although not considered a VCS, the EPA incorporates by 
reference, ``Purge-And-Trap For Aqueous Samples'' (SW-846-5030B), 
``Volatile, Nonpurgeable, Water-Soluble Compounds by Azeotropic 
Distillation'' (SW-846-5031), and ``Volatile Organic Compounds by Gas 
Chromatography/Mass Spectrometry (GC/MS)'' (SW-846-8260D) into 40 CFR 
63.2492(b) and (c)(1); and ``Air Stripping Method (Modified El Paso 
Method) for Determination of Volatile Organic Compound Emissions from 
Water Sources,'' into 40 CFR 63.2490(d)(1)(iii)(A) and (B), and 40 CFR 
63.2525(r)(4)(iv)(A). Each of these methods is used to identify organic 
HAP in water; however, SW-846-5031, SW-846-8260D, and SW-846-5030B use 
water sampling techniques and the Modified El Paso Method uses an air 
stripping sampling technique. The SW-846 methods are reasonably 
available from the EPA at https://www.epa.gov/hw-sw846 while the 
Modified El Paso Method is reasonably available from TCEQ at https://www.tceq.texas.gov/assets/public/compliance/field_ops/guidance/samplingappp.pdf.

[[Page 49132]]

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

    The EPA believes that this action does not have disproportionately 
high and adverse human health or environmental effects on minority 
populations, low-income populations, and/or indigenous peoples, as 
specified in Executive Order 12898 (59 FR 7629, February 16, 1994).
    The documentation for this decision is contained in section IV.A of 
this preamble and in the technical report, Risk and Technology Review--
Analysis of Demographic Factors for Populations Living Near 
Miscellaneous Organic Chemical Manufacturing Source Category 
Operations, available in the docket for this rulemaking (see Docket 
Item No. EPA-HQ-OAR-2018-0746-0013).

L. Congressional Review Act (CRA)

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

List of Subjects in 40 CFR Part 63

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

Andrew Wheeler,
Administrator.

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

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

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

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

Subpart A--General Provisions

0
2. Section 63.14 is amended by:
0
a. Revising paragraphs (h)(73), (94), and (102);
0
b. Redesignating paragraphs (n)(14) through (25) as paragraphs (n)(17) 
through (28) and paragraphs (n)(10) through (13) as paragraphs (n)(12) 
through (15);
0
c. Adding new paragraphs (n)(10), (11), and (16); and
0
d. Revising paragraph (t)(1).
    The revisions and additions read as follows:

Sec.  63.14  Incorporations by reference.

* * * * *
    (h) * * *
    (73) ASTM D5790-95 (Reapproved 2012), Standard Test Method for 
Measurement of Purgeable Organic Compounds in Water by Capillary Column 
Gas Chromatography/Mass Spectrometry, Approved June 15, 2012, IBR 
approved for Sec.  63.2485(h) and Table 4 to subpart UUUU.
* * * * *
    (94) ASTM D6420-18, Standard Test Method for Determination of 
Gaseous Organic Compounds by Direct Interface Gas Chromatography-Mass 
Spectrometry, Approved November 1, 2018 IBR approved for Sec. Sec.  
63.987(b), 63.997(e), and 63.2354(b), table 5 to subpart EEEE, and 
Sec.  63.2450(j).
* * * * *
    (102) ASTM D6784-02 (Reapproved 2008), Standard Test Method for 
Elemental, Oxidized, Particle-Bound and Total Mercury in Flue Gas 
Generated from Coal-Fired Stationary Sources (Ontario Hydro Method), 
(Approved April 1, 2008), IBR approved for Sec. Sec.  63.2465(d), 
63.11646(a), and 63.11647(a) and (d) and tables 1, 2, 5, 11, 12t, and 
13 to subpart DDDDD, tables 4 and 5 to subpart JJJJJ, tables 4 and 6 to 
subpart KKKKK, table 4 to subpart JJJJJJ, table 5 to subpart UUUUU, and 
appendix A to subpart UUUUU.
* * * * *
    (n) * * *
    (10) SW-846-5030B, Purge-And-Trap For Aqueous Samples, Revision 2, 
December 1996, in EPA Publication No. SW-846, Test Methods for 
Evaluating Solid Waste, Physical/Chemical Methods, Third Edition, IBR 
approved for Sec.  63.2492(b) and (c).
    (11) SW-846-5031, Volatile, Nonpurgeable, Water-Soluble Compounds 
by Azeotropic Distillation, Revision 0, December 1996, in EPA 
Publication No. SW-846, Test Methods for Evaluating Solid Waste, 
Physical/Chemical Methods, Third Edition, IBR approved for Sec.  
63.2492(b) and (c).
* * * * *
    (16) SW-846-8260D, Volatile Organic Compounds By Gas 
Chromatography/Mass Spectrometry, Revision 4, June 2018, in EPA 
Publication No. SW-846, Test Methods for Evaluating Solid Waste, 
Physical/Chemical Methods, Third Edition, IBR approved for Sec.  
63.2492(b) and (c).
* * * * *
    (t) * * *
    (1) ``Air Stripping Method (Modified El Paso Method) for 
Determination of Volatile Organic Compound Emissions from Water 
Sources,'' Revision Number One, dated January 2003, Sampling Procedures 
Manual, Appendix P: Cooling Tower Monitoring, January 31, 2003, IBR 
approved for Sec. Sec.  63.654(c) and (g), 63.655(i), 63.1086(e), 
63.1089, 63.2490(d), 63.2525(r), and 63.11920.
* * * * *

Subpart FFFF--National Emission Standards for Hazardous Air 
Pollutants: Miscellaneous Organic Chemical Manufacturing

0
3. Section 63.2435 is amended by revising paragraph (c)(3) to read as 
follows:

Sec.  63.2435  Am I subject to the requirements in this subpart?

* * * * *
    (c) * * *
    (3) The affiliated operations located at an affected source under 
subparts GG (National Emission Standards for Aerospace Manufacturing 
and Rework Facilities), KK (National Emission Standards for the 
Printing and Publishing Industry), JJJJ (NESHAP: Paper and Other Web 
Coating), MMMM (NESHAP: Surface Coating of Miscellaneous Metal Parts 
and Products), and SSSS (NESHAP: Surface Coating of Metal Coil) of this 
part. Affiliated operations include, but are not limited to, mixing or 
dissolving of coating ingredients; coating mixing for viscosity 
adjustment, color tint or additive blending, or pH adjustment; cleaning 
of coating lines and coating line parts; handling and storage of 
coatings and solvent; and conveyance and treatment of wastewater.
* * * * *

0
4. Section 63.2445 is amended by revising paragraphs (a) introductory 
text and (b) and adding paragraphs (g) through (i) to read as follows:

Sec.  63.2445  When do I have to comply with this subpart?

    (a) Except as specified in paragraphs (g) through (i) of this 
section, if you have a new affected source, you must comply with this 
subpart according to the requirements in paragraphs (a)(1) and (2) of 
this section.
* * * * *
    (b) Except as specified in paragraphs (g) through (i) of this 
section, if you have an existing source on November 10, 2003, you must 
comply with the requirements for existing sources in this subpart no 
later than May 10, 2008.
* * * * *
    (g) All affected sources that commenced construction or 
reconstruction on or before December 17, 2019, must be in compliance 
with the requirements listed in paragraphs (g)(1) through (7) of this 
section upon

[[Page 49133]]

initial startup or on August 12, 2023, whichever is later. All affected 
sources that commenced construction or reconstruction after December 
17, 2019, must be in compliance with the requirements listed in 
paragraphs (g)(1) through (7) of this section upon initial startup, or 
on August 12, 2020 whichever is later.
    (1) The general requirements specified in Sec. Sec.  63.2450(a)(2), 
(e)(4) through (7), (g)(6) and (7), (i)(3), (j)(5)(ii), (j)(6), 
(k)(1)(ii), (k)(7) and (8), (t), and (u), 63.2520(d)(3) and (e)(11) 
through (13), 63.2525(m) through (o), and 63.2535(m).
    (2) For process vents, the requirements specified in Sec. Sec.  
63.2450(v), 63.2520(e)(14), and 63.2525(p).
    (3) For storage tank degassing, the requirements specified in Sec.  
63.2470(f).
    (4) For equipment leaks and pressure relief devices, the 
requirements specified in Sec. Sec.  63.2480(e) and (f), 63.2520(d)(4) 
and (e)(14), and 63.2525(q).
    (5) For wastewater streams and liquid streams in open systems 
within an MCPU, the requirements specified in Sec.  63.2485(i)(2)(iii), 
(n)(2)(vii), (p), and (q).
    (6) For heat exchange systems, the requirements specified in 
Sec. Sec.  63.2490(d), 63.2520(e)(16), and 63.2525(r).
    (7) The other notification, reports, and records requirements 
specified in Sec. Sec.  63.2500(g), 63.2520(e)(5)(ii)(D) and 
(e)(5)(iii)(M) and (N), and 63.2525(l) and (u).
    (h) All affected sources that commenced construction or 
reconstruction on or before December 17, 2019, must be in compliance 
with the requirements for pumps in light liquid service in Sec.  
63.2480(b)(6) and (c)(10) upon initial startup or on August 12, 2021, 
whichever is later. All affected sources that commenced construction or 
reconstruction after December 17, 2019, must be in compliance with the 
requirements for pumps in light liquid service in Sec.  63.2480(b)(6) 
and (c)(10) upon initial startup, or on August 12, 2020, whichever is 
later.
    (i) All affected sources that commenced construction or 
reconstruction on or before December 17, 2019, must be in compliance 
with the ethylene oxide requirements in Sec. Sec.  63.2450(h) and (r), 
63.2470(b) and (c)(4), 63.2492, 63.2493, 63.2520(d)(5) and (e)(17), and 
63.2525(s) and Table 1 to this subpart, item 5, Table 2 to this 
subpart, item 3, Table 4 to this subpart, item 3, and Table 6 to this 
subpart, item 3, upon initial startup or on August 12, 2022, whichever 
is later. All affected sources that commenced construction or 
reconstruction after December 17, 2019, must be in compliance with the 
ethylene oxide requirements listed in Sec. Sec.  63.2450(h) and (r), 
63.2470(b) and (c)(4), 63.2492, 63.2493, 63.2520(d)(5) and (e)(17), and 
63.2525(s) and Table 1 to this subpart, item 5, Table 2 to this 
subpart, item 3, Table 4 to this subpart, item 3, and Table 6 to this 
subpart, item 3, upon initial startup, or on August 12, 2020, whichever 
is later.

0
5. Section 63.2450 is amended by:
0
a. Revising paragraphs (a), (c)(2) introductory text, and (e)(1) 
through (3);
0
b. Adding paragraphs (e)(4) through (7);
0
c. Revising paragraphs (f) introductory text, (g) introductory text, 
(g)(3)(ii), and (g)(5);
0
d. Adding paragraphs (g)(6) and (7);
0
e. Revising paragraphs (h), (i) introductory text, and (i)(2);
0
f. Adding paragraph (i)(3);
0
g. Revising paragraphs (j) introductory text, (j)(1) introductory text, 
(j)(1)(i), (j)(2)(iii), and (j)(3) through (5);
0
h. Adding paragraph (j)(6);
0
i. Revising paragraphs (k) introductory text, (k)(1), and (k)(4)(iv);
0
j. Adding paragraphs (k)(7) and (8);
0
k. Revising paragraphs (p) and (r); and
0
l. Adding paragraphs (t), (u), and (v).
    The revisions and additions read as follows:

Sec.  63.2450  What are my general requirements for complying with this 
subpart?

    (a) General. You must comply with paragraphs (a)(1) and (2) of this 
section.
    (1) Except as specified in paragraph (a)(2) of this section, you 
must be in compliance with the emission limits and work practice 
standards in Tables 1 through 7 to this subpart at all times, except 
during periods of startup, shutdown, and malfunction (SSM), and you 
must meet the requirements specified in Sec. Sec.  63.2455 through 
63.2490 (or the alternative means of compliance in Sec.  63.2495, Sec.  
63.2500, or Sec.  63.2505), except as specified in paragraphs (b) 
through (s) of this section. You must meet the notification, reporting, 
and recordkeeping requirements specified in Sec. Sec.  63.2515, 
63.2520, and 63.2525.
    (2) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), paragraph (a)(1) of this section no longer applies. 
Instead, you must be in compliance with the emission limits and work 
practice standards in Tables 1 through 7 to this subpart at all times, 
and you must meet the requirements specified in Sec. Sec.  63.2455 
through 63.2490 (or the alternative means of compliance in Sec.  
63.2495, Sec.  63.2500, or Sec.  63.2505), except as specified in 
paragraphs (b) through (v) of this section. You must meet the 
notification, reporting, and recordkeeping requirements specified in 
Sec. Sec.  63.2515, 63.2520, and 63.2525.
* * * * *
    (c) * * *
    (2) Determine the applicable requirements based on the hierarchy 
presented in paragraphs (c)(2)(i) through (vi) of this section. For a 
combined stream, the applicable requirements are specified in the 
highest-listed paragraph in the hierarchy that applies to any of the 
individual streams that make up the combined stream. For example, if a 
combined stream consists of emissions from Group 1 batch process vents 
and any other type of emission stream, then you must comply with the 
requirements in paragraph (c)(2)(i) of this section for the combined 
stream; compliance with the requirements in paragraph (c)(2)(i) of this 
section constitutes compliance for the other emission streams in the 
combined stream. Two exceptions are that you must comply with the 
requirements in Table 3 to this subpart and Sec.  63.2465 for all 
process vents with hydrogen halide and halogen HAP emissions, and 
recordkeeping requirements for Group 2 applicability or compliance are 
still required (e.g., the requirement in Sec.  63.2525(e)(3) and (4) to 
track the number of batches produced and calculate rolling annual 
emissions for processes with Group 2 batch process vents).
* * * * *
    (e) * * *
    (1) Except when complying with Sec.  63.2485, if you reduce organic 
HAP emissions by venting emissions through a closed-vent system to any 
combination of control devices (except a flare) or recovery devices, 
you must meet the requirements of paragraph (e)(4) of this section, and 
the requirements of Sec.  63.982(c) and the requirements referenced 
therein.
    (2) Except as specified in paragraph (e)(5) of this section or 
except when complying with Sec.  63.2485, if you reduce organic HAP 
emissions by venting emissions through a closed-vent system to a flare, 
you must meet the requirements of paragraph (e)(4) of this section, and 
the requirements of Sec.  63.982(b) and the requirements referenced 
therein.
    (3) Except as specified in paragraphs (e)(3)(i) and (ii) of this 
section, if you use a halogen reduction device to reduce hydrogen 
halide and halogen HAP emissions from halogenated vent streams, you 
must meet the requirements of paragraph (e)(4) of this section, and the 
requirements of Sec.  63.994 and the requirements referenced therein. 
If you use a halogen reduction device before a combustion

[[Page 49134]]

device, you must determine the halogen atom emission rate prior to the 
combustion device according to the procedures in Sec.  63.115(d)(2)(v).
    (i) Beginning on and after October 13, 2020, performance test 
reports must be submitted according to the procedures in Sec.  
63.2520(f).
    (ii) If you use a halogen reduction device other than a scrubber, 
then you must submit procedures for establishing monitoring parameters 
to the Administrator as part of your precompliance report as specified 
in Sec.  63.2520(c)(8).
    (4) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), the referenced provisions specified in paragraphs (e)(4)(i) 
through (xvi) of this section do not apply when demonstrating 
compliance with subpart SS of this part.
    (i) The phrase ``Except for equipment needed for safety purposes 
such as pressure relief devices, low leg drains, high point bleeds, 
analyzer vents, and open-ended valves or lines'' in Sec.  63.983(a)(3) 
of subpart SS.
    (ii) The second sentence of Sec.  63.983(a)(5) of subpart SS.
    (iii) The phrase ``except during periods of start-up, shutdown and 
malfunction as specified in the referencing subpart'' in Sec.  
63.984(a) of subpart SS.
    (iv) The phrase ``except during periods of start-up, shutdown, and 
malfunction as specified in the referencing subpart'' in Sec.  
63.985(a) of subpart SS.
    (v) The phrase ``other than start-ups, shutdowns, or malfunctions'' 
in Sec.  63.994(c)(1)(ii)(D) of subpart SS.
    (vi) Section 63.996(c)(2)(ii) of subpart SS.
    (vii) The last sentence of Sec.  63.997(e)(1)(i) of subpart SS.
    (viii) Section 63.998(b)(2)(iii) of subpart SS.
    (ix) The phrase ``other than start-ups, shutdowns or malfunctions'' 
in Sec.  63.998(b)(5)(i)(A) of subpart SS.
    (x) The phrase ``other than a start-up, shutdown, or malfunction'' 
from Sec.  63.998(b)(5)(i)(B)(3) of subpart SS.
    (xi) The phrase ``other than start-ups, shutdowns or malfunctions'' 
in Sec.  63.998(b)(5)(i)(C) of subpart SS.
    (xii) The phrase ``other than a start-up, shutdown, or 
malfunction'' from Sec.  63.998(b)(5)(ii)(C) of subpart SS.
    (xiii) The phrase ``except as provided in paragraphs (b)(6)(i)(A) 
and (B) of this section'' in Sec.  63.998(b)(6)(i) of subpart SS.
    (xiv) The second sentence of Sec.  63.998(b)(6)(ii) of subpart SS.
    (xv) Section 63.998(c)(1)(ii)(D), (E), (F), and (G) of subpart SS.
    (xvi) Section 63.998(d)(3) of subpart SS.
    (5) For any flare that is used to reduce organic HAP emissions from 
an MCPU, you may elect to comply with the requirements in this 
paragraph in lieu of the requirements of Sec.  63.982(b) and the 
requirements referenced therein. However, beginning no later than the 
compliance dates specified in Sec.  63.2445(g), paragraphs (e)(2) and 
(f) of this section no longer apply to flares that control ethylene 
oxide emissions from affected sources in ethylene oxide service as 
defined in Sec.  63.2550 and flares used to control emissions from 
MCPUs that produce olefins or polyolefins. Instead, if you reduce 
organic HAP emissions by venting emissions through a closed-vent system 
to a steam-assisted, air-assisted, non-assisted, or pressure-assisted 
multi-point flare that controls ethylene oxide emissions from affected 
sources in ethylene oxide service as defined in Sec.  63.2550 or is 
used to control emissions from an MCPU that produces olefins or 
polyolefins, then you must meet the applicable requirements for flares 
as specified in Sec. Sec.  63.670 and 63.671 of subpart CC, including 
the provisions in Tables 12 and 13 to subpart CC of this part, except 
as specified in paragraphs (e)(5)(i) through (xiii) of this section. 
This requirement in this paragraph (e)(5) also applies to any flare 
using fuel gas from a fuel gas system, of which 50 percent or more of 
the fuel gas is derived from an MCPU that has processes and/or 
equipment in ethylene oxide service or that produces olefins or 
polyolefins, as determined on an annual average basis. For purposes of 
compliance with this paragraph (e)(5), the following terms are defined 
in Sec.  63.641 of subpart CC: Assist air, assist steam, center steam, 
combustion zone, combustion zone gas, flare, flare purge gas, flare 
supplemental gas, flare sweep gas, flare vent gas, lower steam, net 
heating value, perimeter assist air, pilot gas, premix assist air, 
total steam, and upper steam. Also, for purposes of compliance with 
this paragraph (e)(5), ``MCPUs that produces olefins or polyolefins'' 
includes only those MCPUs that manufacture ethylene, propylene, 
polyethylene, and/or polypropylene as a product. By-products and 
impurities as defined in Sec.  63.101, as well as wastes and trace 
contaminants, are not considered products.
    (i) When determining compliance with the pilot flame requirements 
specified in Sec.  63.670(b) and (g), substitute ``pilot flame or flare 
flame'' for each occurrence of ``pilot flame.''
    (ii) When determining compliance with the flare tip velocity and 
combustion zone operating limits specified in Sec.  63.670(d) and (e), 
the requirement effectively applies starting with the 15-minute block 
that includes a full 15 minutes of the flaring event. You are required 
to demonstrate compliance with the velocity and NHVcz requirements 
starting with the block that contains the fifteenth minute of a flaring 
event. You are not required to demonstrate compliance for the previous 
15-minute block in which the event started and contained only a 
fraction of flow.
    (iii) Instead of complying with paragraph (o)(2)(i) of Sec.  63.670 
of subpart CC, you must develop and implement the flare management plan 
no later than the compliance dates specified in Sec.  63.2445(g).
    (iv) Instead of complying with paragraph (o)(2)(iii) of Sec.  
63.670 of subpart CC, if required to develop a flare management plan 
and submit it to the Administrator, then you must also submit all 
versions of the plan in portable document format (PDF) to the EPA via 
the Compliance and Emissions Data Reporting Interface (CEDRI), which 
can be accessed through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). The EPA will make all the information submitted through 
CEDRI available to the public without further notice to you. Do not use 
CEDRI to submit information you claim as confidential business 
information (CBI). Anything submitted using CEDRI cannot later be 
claimed to be CBI. Although we do not expect persons to assert a claim 
of CBI, if you wish to assert a CBI claim, submit a version with the 
CBI omitted via CEDRI. A complete plan, including information claimed 
to be CBI and clearly marked as CBI, must be mailed to the following 
address: U.S. Environmental Protection Agency, Office of Air Quality 
Planning and Standards, Sector Policies and Programs Division, CORE CBI 
Office, U.S. EPA Mailroom (C404-02), Attention: Miscellaneous Organic 
Chemical Manufacturing Sector Lead, 4930 Old Page Rd., Durham, NC 
27703. All CBI claims must be asserted at the time of submission. 
Furthermore, under CAA section 114(c) emissions data is not entitled to 
confidential treatment, and the EPA is required to make emissions data 
available to the public. Thus, emissions data will not be protected as 
CBI and will be made publicly available.
    (v) Section 63.670(o)(3)(ii) of subpart CC and all references to 
Sec.  63.670(o)(3)(ii) of subpart CC do not apply. Instead, the owner 
or operator

[[Page 49135]]

must comply with the maximum flare tip velocity operating limit at all 
times.
    (vi) Substitute ``MCPU'' for each occurrence of ``petroleum 
refinery.''
    (vii) Each occurrence of ``refinery'' does not apply.
    (viii) If a pressure-assisted multi-point flare is used as a 
control device, then you must meet the following conditions:
    (A) You are not required to comply with the flare tip velocity 
requirements in paragraph (d) and (k) of Sec.  63.670 of subpart CC;
    (B) You must substitute ``800'' for each occurrence of ``270'' in 
paragraph (e) of Sec.  63.670 of subpart CC;
    (C) You must determine the 15-minute block average NHVvg using only 
the direct calculation method specified in in paragraph (l)(5)(ii) of 
Sec.  63.670 of subpart CC;
    (D) Instead of complying with paragraph (b) and (g) of Sec.  63.670 
of subpart CC, if a pressure-assisted multi-point flare uses cross-
lighting on a stage of burners rather than having an individual pilot 
flame on each burner, then you must operate each stage of the pressure-
assisted multi-point flare with a flame present at all times when 
regulated material is routed to that stage of burners. Each stage of 
burners that cross-lights in the pressure-assisted multi-point flare 
must have at least two pilots with at least one continuously lit and 
capable of igniting all regulated material that is routed to that stage 
of burners. Each 15-minute block during which there is at least one 
minute where no pilot flame is present on a stage of burners when 
regulated material is routed to the flare is a deviation of the 
standard. Deviations in different 15-minute blocks from the same event 
are considered separate deviations. The pilot flame(s) on each stage of 
burners that use cross-lighting must be continuously monitored by a 
thermocouple or any other equivalent device used to detect the presence 
of a flame;
    (E) Unless you choose to conduct a cross-light performance 
demonstration as specified in this paragraph (e)(5)(viii)(E), you must 
ensure that if a stage of burners on the flare uses cross-lighting, 
that the distance between any two burners in series on that stage is no 
more than 6 feet when measured from the center of one burner to the 
next burner. A distance greater than 6 feet between any two burners in 
series may be used provided you conduct a performance demonstration 
that confirms the pressure-assisted multi-point flare will cross-light 
a minimum of three burners and the spacing between the burners and 
location of the pilot flame must be representative of the projected 
installation. The compliance demonstration must be approved by the 
permitting authority and a copy of this approval must be maintained 
onsite. The compliance demonstration report must include: A protocol 
describing the test methodology used, associated test method QA/QC 
parameters, the waste gas composition and NHVcz of the gas tested, the 
velocity of the waste gas tested, the pressure-assisted multi-point 
flare burner tip pressure, the time, length, and duration of the test, 
records of whether a successful cross-light was observed over all of 
the burners and the length of time it took for the burners to cross-
light, records of maintaining a stable flame after a successful cross-
light and the duration for which this was observed, records of any 
smoking events during the cross-light, waste gas temperature, 
meteorological conditions (e.g., ambient temperature, barometric 
pressure, wind speed and direction, and relative humidity), and whether 
there were any observed flare flameouts; and
    (F) You must install and operate pressure monitor(s) on the main 
flare header, as well as a valve position indicator monitoring system 
for each staging valve to ensure that the flare operates within the 
proper range of conditions as specified by the manufacturer. The 
pressure monitor must meet the requirements in Table 13 to subpart CC 
of this part.
    (G) If a pressure-assisted multi-point flare is operating under the 
requirements of an approved alternative means of emission limitations, 
you must either continue to comply with the terms of the alternative 
means of emission limitations or comply with the provisions in 
paragraphs (e)(5)(viii)(A) through (F) of this section.
    (ix) If you choose to determine compositional analysis for net 
heating value with a continuous process mass spectrometer, then you 
must comply with the requirements specified in paragraphs (e)(5)(ix)(A) 
through (G) of this section.
    (A) You must meet the requirements in Sec.  63.671(e)(2). You may 
augment the minimum list of calibration gas components found in Sec.  
63.671(e)(2) with compounds found during a pre-survey or known to be in 
the gas through process knowledge.
    (B) Calibration gas cylinders must be certified to an accuracy of 2 
percent and traceable to National Institute of Standards and Technology 
(NIST) standards.
    (C) For unknown gas components that have similar analytical mass 
fragments to calibration compounds, you may report the unknowns as an 
increase in the overlapped calibration gas compound. For unknown 
compounds that produce mass fragments that do not overlap calibration 
compounds, you may use the response factor for the nearest molecular 
weight hydrocarbon in the calibration mix to quantify the unknown 
component's NHVvg.
    (D) You may use the response factor for n-pentane to quantify any 
unknown components detected with a higher molecular weight than n-
pentane.
    (E) You must perform an initial calibration to identify mass 
fragment overlap and response factors for the target compounds.
    (F) You must meet applicable requirements in Performance 
Specification 9 of 40 CFR part 60, appendix B, for continuous 
monitoring system acceptance including, but not limited to, performing 
an initial multi-point calibration check at three concentrations 
following the procedure in Section 10.1 and performing the periodic 
calibration requirements listed for gas chromatographs in Table 13 to 
subpart CC of this part, for the process mass spectrometer. You may use 
the alternative sampling line temperature allowed under Net Heating 
Value by Gas Chromatograph in Table 13 to subpart CC of this part.
    (G) The average instrument calibration error (CE) for each 
calibration compound at any calibration concentration must not differ 
by more than 10 percent from the certified cylinder gas value. The CE 
for each component in the calibration blend must be calculated using 
Equation 1 to this paragraph (e)(5)(ix)(G).
[GRAPHIC] [TIFF OMITTED] TR12AU20.000

Where:

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

    (x) If you use a gas chromatograph or mass spectrometer for 
compositional analysis for net heating value, then you may choose to 
use the CE of NHVmeasured versus the cylinder tag value NHV 
as the measure of agreement for daily calibration and quarterly audits 
in lieu of determining the compound-specific CE. The CE for NHV at any 
calibration level must not differ by more than 10 percent from the 
certified cylinder gas value. The CE for must be calculated using 
Equation 2 to this paragraph (e)(5)(x).
[GRAPHIC] [TIFF OMITTED] TR12AU20.001

Where:

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

[[Page 49136]]

    (xi) Instead of complying with paragraph (q) of Sec.  63.670 of 
subpart CC, you must comply with the reporting requirements specified 
in Sec.  63.2520(d)(3) and (e)(11).
    (xii) Instead of complying with paragraph (p) of Sec.  63.670 of 
subpart CC, you must keep the flare monitoring records specified in 
Sec.  63.2525(m).
    (xiii) You may elect to comply with the alternative means of 
emissions limitation requirements specified in paragraph (r) of Sec.  
63.670 of subpart CC in lieu of the requirements in paragraphs (d) 
through (f) of Sec.  63.670 of subpart CC, as applicable. However, 
instead of complying with paragraph (r)(3)(iii) of Sec.  63.670 of 
subpart CC, you must also submit the alternative means of emissions 
limitation request to the following address: U.S. Environmental 
Protection Agency, Office of Air Quality Planning and Standards, Sector 
Policies and Programs Division, U.S. EPA Mailroom (C404-02), Attention: 
Miscellaneous Organic Chemical Manufacturing Sector Lead, 4930 Old Page 
Rd., Durham, NC 27703.
    (6) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), the use of a bypass line at any time on a closed vent 
system to divert emissions subject to the requirements in Tables 1 
through 7 to this subpart to the atmosphere or to a control device not 
meeting the requirements specified in Tables 1 through 7 to this 
subpart is an emissions standards deviation. You must also comply with 
the requirements specified in paragraphs (e)(6)(i) through (v) of this 
section, as applicable:
    (i) If you are subject to the bypass monitoring requirements of 
Sec.  63.148(f) of subpart G, then you must continue to comply with the 
requirements in Sec.  63.148(f) of subpart G and the recordkeeping and 
reporting requirements in Sec. Sec.  63.148(j)(2) and (3) of subpart G, 
and (h)(3) of subpart G, in addition to the applicable requirements 
specified in Sec.  63.2485(q), the recordkeeping requirements specified 
in Sec.  63.2525(n), and the reporting requirements specified in Sec.  
63.2520(e)(12).
    (ii) If you are subject to the bypass monitoring requirements of 
Sec.  63.172(j) of subpart H, then you must continue to comply with the 
requirements in Sec.  63.172(j) of subpart H and the recordkeeping and 
reporting requirements in Sec.  63.118(a)(3) and (4), and (f)(3) and 
(4) of subpart G, in addition to the applicable requirements specified 
in Sec. Sec.  63.2480(f) and 63.2485(q), the recordkeeping requirements 
specified in Sec.  63.2525(n), and the reporting requirements specified 
in Sec.  63.2520(e)(12).
    (iii) If you are subject to the bypass monitoring requirements of 
Sec.  63.983(a)(3) of subpart SS, then you must continue to comply with 
the requirements in Sec.  63.983(a)(3) of subpart SS and the 
recordkeeping and reporting requirements in Sec. Sec.  63.998(d)(1)(ii) 
and 63.999(c)(2) of subpart SS, in addition to the requirements 
specified in Sec.  63.2450(e)(4), the recordkeeping requirements 
specified in Sec.  63.2525(n), and the reporting requirements specified 
in Sec.  63.2520(e)(12).
    (iv) If you are subject to the bypass monitoring requirements of 
Sec.  65.143(a)(3) of this chapter, then you must continue to comply 
with the requirements in Sec.  65.143(a)(3) and the recordkeeping and 
reporting requirements in Sec. Sec.  65.163(a)(1) and 65.166(b) of this 
chapter; in addition to the applicable requirements specified in Sec.  
63.2480(f), the recordkeeping requirements specified in Sec.  
63.2525(n), and the reporting requirements specified in Sec.  
63.2520(e)(12).
    (v) For purposes of compliance with this paragraph (e)(6), 
Sec. Sec.  63.148(f)(3) of subpart G, and 63.172(j)(3) of subpart H, 
the phrase ``Except for equipment needed for safety purposes such as 
pressure relief devices, low leg drains, high point bleeds, analyzer 
vents, and open-ended valves or lines'' in Sec.  63.983(a)(3) of 
subpart SS, and the phrase ``Except for pressure relief devices needed 
for safety purposes, low leg drains, high point bleeds, analyzer vents, 
and open-ended valves or lines'' in Sec.  65.143(a)(3) of this chapter 
do not apply; instead, the exemptions specified in paragraphs 
(e)(6)(v)(A) and (B) of this section apply.
    (A) Except for pressure relief devices subject to Sec.  
63.2480(e)(4), equipment such as low leg drains and equipment subject 
to the requirements specified in Sec.  63.2480 are not subject to this 
paragraph (e)(6).
    (B) Open-ended valves or lines that use a cap, blind flange, plug, 
or second valve and follow the requirements specified in 40 CFR 60.482-
6(a)(2), (b), and (c) or follow requirements codified in another 
regulation that are the same as 40 CFR 60.482-6(a)(2), (b), and (c) are 
not subject to this paragraph (e)(6).
    (7) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), if you reduce organic HAP emissions by venting emissions 
through a closed-vent system to an adsorber(s) that cannot be 
regenerated or a regenerative adsorber(s) that is regenerated offsite, 
then you must comply with paragraphs (e)(4) and (6) of this section and 
the requirements in Sec.  63.983, and you must install a system of two 
or more adsorber units in series and comply with the requirements 
specified in paragraphs (e)(7)(i) through (iii) of this section.
    (i) Conduct an initial performance test or design evaluation of the 
adsorber and establish the breakthrough limit and adsorber bed life.
    (ii) Monitor the HAP or total organic compound (TOC) concentration 
through a sample port at the outlet of the first adsorber bed in series 
according to the schedule in paragraph (e)(7)(iii)(B) of this section. 
You must measure the concentration of HAP or TOC using either a 
portable analyzer, in accordance with Method 21 of 40 CFR part 60, 
appendix A-7, using methane, propane, isobutylene, or the primary HAP 
being controlled as the calibration gas or Method 25A of 40 CFR part 
60, appendix A-7, using methane, propane, or the primary HAP being 
controlled as the calibration gas.
    (iii) Comply with paragraph (e)(7)(iii)(A) of this section, and 
comply with the monitoring frequency according to paragraph 
(e)(7)(iii)(B) of this section.
    (A) The first adsorber in series must be replaced immediately when 
breakthrough, as defined in Sec.  63.2550(i), is detected between the 
first and second adsorber. The original second adsorber (or a fresh 
canister) will become the new first adsorber and a fresh adsorber will 
become the second adsorber. For purposes of this paragraph 
(e)(7)(iii)(A), ``immediately'' means within 8 hours of the detection 
of a breakthrough for adsorbers of 55 gallons or less, and within 24 
hours of the detection of a breakthrough for adsorbers greater than 55 
gallons. You must monitor at the outlet of the first adsorber within 3 
days of replacement to confirm it is performing properly.
    (B) Based on the adsorber bed life established according to 
paragraph (e)(7)(i) of this section and the date the adsorbent was last 
replaced, conduct monitoring to detect breakthrough at least monthly if 
the adsorbent has more than 2 months of life remaining, at least weekly 
if the adsorbent has between 2 months and 2 weeks of life remaining, 
and at least daily if the adsorbent has 2 weeks or less of life 
remaining.
    (f) Requirements for flare compliance assessments. Except as 
specified in paragraph (e)(5) of this section, you must comply with 
paragraphs (f)(1) and (2) of this section.
* * * * *
    (g) Requirements for performance tests. The requirements specified 
in paragraphs (g)(1) through (7) of this

[[Page 49137]]

section apply instead of or in addition to the requirements specified 
in subpart SS of this part.
* * * * *
    (3) * * *
    (ii) If you elect to comply with the outlet TOC concentration 
emission limits in Tables 1 through 7 to this subpart, and the 
uncontrolled or inlet gas stream to the control device contains greater 
than 10 percent (volume concentration) carbon disulfide, you must use 
Method 18 or Method 15 of 40 CFR part 60, appendix A, to separately 
determine the carbon disulfide concentration. Calculate the total HAP 
or TOC emissions by totaling the carbon disulfide emissions measured 
using Method 18 or 15 of 40 CFR part 60, appendix A, and the other HAP 
emissions measured using Method 18 or 25A of 40 CFR part 60, appendix 
A.
* * * * *
    (5) Section 63.997(c)(1) does not apply. For the purposes of this 
subpart, results of all initial compliance demonstrations must be 
included in the notification of compliance status report, which is due 
150 days after the compliance date, as specified in Sec.  
63.2520(d)(1). If the initial compliance demonstration includes a 
performance test and the results are submitted electronically via CEDRI 
in accordance with Sec.  63.2520(f), the process unit(s) tested, the 
pollutant(s) tested, and the date that such performance test was 
conducted may be submitted in the notification of compliance status 
report in lieu of the performance test results. The performance test 
results must be submitted to CEDRI by the date the notification of 
compliance status report is submitted.
    (6) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), in lieu of the requirements specified in Sec.  63.7(e)(1) 
of subpart A you must conduct performance tests under such conditions 
as the Administrator specifies based on representative performance of 
the affected source for the period being tested. Representative 
conditions exclude periods of startup and shutdown. You may not conduct 
performance tests during periods of malfunction. You must record the 
process information that is necessary to document operating conditions 
during the test and include in such record an explanation to support 
that such conditions represent normal operation. Upon request, you must 
make available to the Administrator such records as may be necessary to 
determine the conditions of performance tests.
    (7) Comply with the requirements in Sec.  63.2450(e)(4), as 
applicable.
    (h) Design evaluation. To determine the percent reduction of a 
small control device that is used to comply with an emission limit 
specified in Table 1, 2, 3, or 5 to this subpart, you may elect to 
conduct a design evaluation as specified in Sec.  63.1257(a)(1) instead 
of a performance test as specified in subpart SS of this part. You must 
establish the value(s) and basis for the operating limits as part of 
the design evaluation. For continuous process vents, the design 
evaluation must be conducted at maximum representative operating 
conditions for the process, unless the Administrator specifies or 
approves alternate operating conditions. For transfer racks, the design 
evaluation must demonstrate that the control device achieves the 
required control efficiency during the reasonably expected maximum 
transfer loading rate. Beginning no later than the compliance dates 
specified in Sec.  63.2445(i), this paragraph (h) does not apply to 
process vents in ethylene oxide service as defined in Sec.  63.2550.
    (i) Outlet concentration correction for combustion devices. Except 
as specified in paragraph (i)(3) of this section, when Sec.  
63.997(e)(2)(iii)(C) requires you to correct the measured concentration 
at the outlet of a combustion device to 3-percent oxygen if you add 
supplemental combustion air, the requirements in either paragraph 
(i)(1) or (2) of this section apply for the purposes of this subpart.
* * * * *
    (2) You must correct the measured concentration for supplemental 
gases using Equation 1 in Sec.  63.2460(c)(6); you may use process 
knowledge and representative operating data to determine the fraction 
of the total flow due to supplemental gas.
    (3) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), paragraphs (i)(1) and (2) of this section no longer apply. 
Instead, when Sec.  63.997(e)(2)(iii)(C) requires you to correct the 
measured concentration at the outlet of a combustion device to 3-
percent oxygen if you add supplemental combustion air, you must follow 
the procedures in Sec.  63.997(e)(2)(iii)(C) to perform the 
concentration correction, except you may also use Method 3A of 40 CFR 
part 60, appendix A-2, to determine the oxygen concentration.
    (j) Continuous emissions monitoring systems. Each continuous 
emissions monitoring system (CEMS) must be installed, operated, and 
maintained according to the requirements in Sec.  63.8 of subpart A and 
paragraphs (j)(1) through (6) of this section.
    (1) Each CEMS must be installed, operated, and maintained according 
to the applicable Performance Specification of 40 CFR part 60, appendix 
B, and the applicable Quality Assurance Procedures of 40 CFR part 60, 
appendix F, and according to paragraph (j)(2) of this section, except 
as specified in paragraph (j)(1)(i) of this section. For any CEMS 
meeting Performance Specification 8 of 40 CFR part 60, appendix B, you 
must also comply with procedure 1 of 40 CFR part 60, appendix F. Locate 
the sampling probe or other interface at a measurement location such 
that you obtain representative measurements of emissions from the 
regulated source. For CEMS installed after August 12, 2020, conduct a 
performance evaluation of each CEMS within 180 days of installation of 
the monitoring system.
    (i) If you wish to use a CEMS other than a Fourier Transform 
Infrared Spectroscopy (FTIR) meeting the requirements of Performance 
Specification 15 of 40 CFR part 60, appendix B, to measure hydrogen 
halide, other than hydrogen chloride, and halogen HAP or CEMS meeting 
the requirements of Performance Specification 18 of 40 CFR part 60, 
appendix B, to measure hydrogen chloride before we promulgate a 
Performance Specification for such CEMS, you must prepare a monitoring 
plan and submit it for approval in accordance with the procedures 
specified in Sec.  63.8 of subpart A.
* * * * *
    (2) * * *
    (iii) For CEMS meeting Performance Specification 8 of 40 CFR part 
60, appendix B, used to monitor performance of a noncombustion device, 
determine the predominant organic HAP using either process knowledge or 
the screening procedures of Method 18 of 40 CFR part 60, appendix A-6, 
on the control device inlet stream, calibrate the monitor on the 
predominant organic HAP, and report the results as C1. Use 
Method 18 of 40 CFR part 60, appendix A-6, Method 320 of appendix A to 
this part, ASTM D6420-18 (incorporated by reference, see Sec.  63.14), 
or any approved alternative as the reference method for the relative 
accuracy tests, and report the results as C1.
    (3) You must conduct a performance evaluation of each CEMS 
according to the requirements in Sec.  63.8 of subpart A and according 
to the applicable Performance Specification of 40 CFR part 60, appendix 
B, except that the schedule in Sec.  63.8(e)(4) of subpart A does not 
apply, and before October 13, 2020, the results of the performance 
evaluation must be included in the

[[Page 49138]]

notification of compliance status report. Unless otherwise specified in 
this subpart, beginning on and after October 13, 2020, the results of 
the performance evaluation must be submitted in accordance with Sec.  
63.2520(g).
    (4) The CEMS data must be reduced to operating day or operating 
block averages computed using valid data consistent with the data 
availability requirements specified in Sec.  63.999(c)(6)(i)(B) through 
(D), except monitoring data also are sufficient to constitute a valid 
hour of data if measured values are available for at least two of the 
15-minute periods during an hour when calibration, quality assurance, 
or maintenance activities are being performed. An operating block is a 
period of time from the beginning to end of batch operations within a 
process. Operating block averages may be used only for batch process 
vent data. In computing operating day or operating block averages to 
determine compliance with this subpart, you must exclude monitoring 
data recorded during CEMS breakdowns, out-of-control periods, repairs, 
maintenance periods, calibration checks, or other quality assurance 
activities. Out-of-control periods are as specified in Sec.  63.8(c)(7) 
of subpart A.
    (5) If you add supplemental gases, you must comply with paragraphs 
(j)(5)(i) and (ii) of this section.
    (i) Except as specified in paragraph (j)(5)(ii) of this section, 
correct the measured concentrations in accordance with paragraph (i) of 
this section and Sec.  63.2460(c)(6).
    (ii) Beginning no later than the compliance dates specified in 
Sec.  63.2445(g), you must use Performance Specification 3 of 40 CFR 
part 60, appendix B, to certify your oxygen CEMS, and you must comply 
with procedure 1 of 40 CFR part 60, appendix F. Use Method 3A of 40 CFR 
part 60, appendix A-2, as the reference method when conducting a 
relative accuracy test audit.
    (6) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), in lieu of the requirements specified in Sec.  63.8(d)(3) 
of subpart A you must keep the written procedures required by Sec.  
63.8(d)(2) of subpart A on record for the life of the affected source 
or until the affected source is no longer subject to the provisions of 
this part, to be made available for inspection, upon request, by the 
Administrator. If the performance evaluation plan is revised, you must 
keep previous (i.e., superseded) versions of the performance evaluation 
plan on record to be made available for inspection, upon request, by 
the Administrator, for a period of 5 years after each revision to the 
plan. The program of corrective action should be included in the plan 
required under Sec.  63.8(d)(2) of subpart A. In addition to the 
information required in Sec.  63.8(d)(2) of subpart A, your written 
procedures for CEMS must include the information in paragraphs 
(j)(6)(i) through (vi) of this section:
    (i) Description of CEMS installation location.
    (ii) Description of the monitoring equipment, including the 
manufacturer and model number for all monitoring equipment components 
and the span of the analyzer.
    (iii) Routine quality control and assurance procedures.
    (iv) Conditions that would trigger a CEMS performance evaluation, 
which must include, at a minimum, a newly installed CEMS; a process 
change that is expected to affect the performance of the CEMS; and the 
Administrator's request for a performance evaluation under section 114 
of the Clean Air Act.
    (v) Ongoing operation and maintenance procedures in accordance with 
the general requirements of Sec.  63.8(c)(1) and (3), (c)(4)(ii), and 
(c)(7) and (8) of subpart A;
    (vi) Ongoing recordkeeping and reporting procedures in accordance 
with the general requirements of Sec.  63.10(c) and (e)(1) of subpart 
A.
    (k) Continuous parameter monitoring. The provisions in paragraphs 
(k)(1) through (8) of this section apply in addition to the 
requirements for continuous parameter monitoring system (CPMS) in 
subpart SS of this part.
    (1) You must comply with paragraphs (k)(1)(i) and (ii) of this 
section.
    (i) Except as specified in paragraph (k)(1)(ii) of this section, 
record the results of each calibration check and all maintenance 
performed on the CPMS as specified in Sec.  63.998(c)(1)(ii)(A).
    (ii) Beginning no later than the compliance dates specified in 
Sec.  63.2445(g), paragraph (k)(1)(i) of this section no longer 
applies. Instead, you must record the results of each calibration check 
and all maintenance performed on the CPMS as specified in Sec.  
63.998(c)(1)(ii)(A), except you must record all maintenance, not just 
preventative maintenance.
* * * * *
    (4) * * *
    (iv) Recording the downstream temperature and temperature 
difference across the catalyst bed as specified in Sec.  
63.998(a)(2)(ii)(B)(2) and (c)(2)(ii) is not required.
* * * * *
    (7) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), the manufacturer's specifications or your written 
procedures must include a schedule for calibrations, preventative 
maintenance procedures, a schedule for preventative maintenance, and 
corrective actions to be taken if a calibration fails. If a CPMS 
calibration fails, the CPMS is considered to be inoperative until you 
take corrective action and the system passes calibration. You must 
record the nature and cause of instances when the CPMS is inoperative 
and the corrective action taken.
    (8) You must comply with the requirements in paragraph (e)(4) of 
this section, as applicable.
* * * * *
    (p) Original safety device requirements. Except as specified in 
paragraph (t) of this section, opening a safety device, as defined in 
Sec.  63.2550, is allowed at any time conditions require it to avoid 
unsafe conditions.
* * * * *
    (r) Surge control vessels and bottoms receivers. For each surge 
control vessel or bottoms receiver that meets the capacity and vapor 
pressure thresholds for a Group 1 storage tank, you must meet emission 
limits and work practice standards specified in Table 4 to this 
subpart. Beginning no later than the compliance dates specified in 
Sec.  63.2445(i), for each surge control vessel and bottoms receiver in 
ethylene oxide service as defined in Sec.  63.2550, you must also meet 
the applicable process vent requirements specified in Sec. Sec.  
63.2492 and 63.2493(a) through (c).
* * * * *
    (t) New safety device requirements. Beginning no later than the 
compliance dates specified in Sec.  63.2445(g), paragraph (p) of this 
section no longer applies. Instead, you must comply with the 
requirements specified in Sec.  63.2480(e).
    (u) General duty. Beginning no later than the compliance dates 
specified in Sec.  63.2445(g), at all times, you must operate and 
maintain any affected source, including associated air pollution 
control equipment and monitoring equipment, in a manner consistent with 
safety and good air pollution control practices for minimizing 
emissions. The general duty to minimize emissions does not require you 
to make any further efforts to reduce emissions if levels required by 
the applicable standard have been achieved. Determination of whether a 
source is operating in compliance with operation and maintenance 
requirements will be based on

[[Page 49139]]

information available to the Administrator which may include, but is 
not limited to, monitoring results, review of operation and maintenance 
procedures, review of operation and maintenance records, and inspection 
of the source.
    (v) Maintenance vents. Beginning no later than the compliance dates 
specified in Sec.  63.2445(g), you may designate a process vent as a 
maintenance vent if the vent is only used as a result of startup, 
shutdown, maintenance, or inspection of equipment where equipment is 
emptied, depressurized, degassed, or placed into service. You must 
comply with the applicable requirements in paragraphs (v)(1) through 
(3) of this section for each maintenance vent. Any vent designated as a 
maintenance vent is only subject to the maintenance vent provisions in 
this paragraph (v) and the associated recordkeeping and reporting 
requirements in Sec. Sec.  63.2525(p) and 63.2520(e)(14), respectively. 
You do not need to designate a maintenance vent as a Group 1 or Group 2 
process vent nor identify maintenance vents in a Notification of 
Compliance Status report.
    (1) Prior to venting to the atmosphere, remove process liquids from 
the equipment as much as practical and depressurize the equipment to 
either: A flare meeting the requirements of paragraph (e)(2) or (5) of 
this section, as applicable, or a non-flare control device meeting the 
requirements in paragraph (e)(4) of this section and the requirements 
specified in Sec.  63.982(c)(2) of subpart SS until one of the 
following conditions, as applicable, is met.
    (i) The vapor in the equipment served by the maintenance vent has a 
lower explosive limit (LEL) of less than 10 percent and has an outlet 
concentration less than or equal to 20 ppmv hydrogen halide and halogen 
HAP.
    (ii) If there is no ability to measure the LEL of the vapor in the 
equipment based on the design of the equipment, the pressure in the 
equipment served by the maintenance vent is reduced to 5 pounds per 
square inch gauge (psig) or less. Upon opening the maintenance vent, 
active purging of the equipment cannot be used until the LEL of the 
vapors in the maintenance vent (or inside the equipment if the 
maintenance is a hatch or similar type of opening) is less than 10 
percent.
    (iii) The equipment served by the maintenance vent contains less 
than 50 pounds of total volatile organic compounds (VOC).
    (iv) If, after applying best practices to isolate and purge 
equipment served by a maintenance vent, none of the applicable 
criterion in paragraphs (v)(1)(i) through (iii) of this section can be 
met prior to installing or removing a blind flange or similar equipment 
blind, then the pressure in the equipment served by the maintenance 
vent must be reduced to 2 psig or less before installing or removing 
the equipment blind. During installation or removal of the equipment 
blind, active purging of the equipment may be used provided the 
equipment pressure at the location where purge gas is introduced 
remains at 2 psig or less.
    (2) Except for maintenance vents complying with the alternative in 
paragraph (v)(1)(iii) of this section, you must determine the LEL or, 
if applicable, equipment pressure using process instrumentation or 
portable measurement devices and follow procedures for calibration and 
maintenance according to manufacturer's specifications.
    (3) For maintenance vents complying with the alternative in 
paragraph (v)(1)(iii) of this section, you must determine mass of VOC 
in the equipment served by the maintenance vent based on the equipment 
size and contents after considering any contents drained or purged from 
the equipment. Equipment size may be determined from equipment design 
specifications. Equipment contents may be determined using process 
knowledge.

0
6. Section 63.2455 is amended by revising paragraph (a) to read as 
follows:

Sec.  63.2455  What requirements must I meet for continuous process 
vents?

    (a) You must meet each emission limit in Table 1 to this subpart 
that applies to your continuous process vents, and you must meet each 
applicable requirement specified in paragraphs (b) through (c) of this 
section and Sec. Sec.  63.2492 and 63.2493(a) through (c).
* * * * *

0
7. Section 63.2460 is amended by revising paragraphs (a), (b)(5) 
introductory text, (b)(5)(iii), (b)(6) introductory text, (c)(2)(i), 
(ii), and (v), the first sentence of (c)(6) introductory text, (c)(9) 
introductory text, (c)(9)(ii) introductory text, (c)(9)(ii)(D), and 
(c)(9)(iii) and (iv) to read as follows:

Sec.  63.2460  What requirements must I meet for batch process vents?

    (a) General. You must meet each emission limit in Table 2 to this 
subpart that applies to you, and you must meet each applicable 
requirement specified in paragraphs (b) and (c) of this section and 
Sec. Sec.  63.2492 and 63.2493(a) through (c).
    (b) * * *
    (5) You may elect to designate the batch process vents within a 
process as Group 1 and not calculate uncontrolled emissions if you 
comply with one of the situations in paragraph (b)(5)(i), (ii), or 
(iii) of this section.
* * * * *
    (iii) If you comply with an emission limit using a flare that meets 
the requirements specified in Sec.  63.987 or Sec.  63.2450(e)(5), as 
applicable.
    (6) You may change from Group 2 to Group 1 in accordance with 
either paragraph (b)(6)(i) or (ii) of this section. Before October 13, 
2020, you must comply with the requirements of this section and submit 
the test report. Beginning on and after October 13, 2020, you must 
comply with the requirements of this section and submit the performance 
test report for the demonstration required in Sec.  63.1257(b)(8) in 
accordance with Sec.  63.2520(f).
* * * * *
    (c) * * *
    (2) * * *
    (i) To demonstrate initial compliance with a percent reduction 
emission limit in Table 2 to this subpart, you must compare the sums of 
the controlled and uncontrolled emissions for the applicable Group 1 
batch process vents within the process, and show that the specified 
reduction is met. This requirement does not apply if you comply with 
the emission limits of Table 2 to this subpart by using a flare that 
meets the requirements of Sec.  63.987 or 63.2450(e)(5), as applicable.
    (ii) When you conduct a performance test or design evaluation for a 
non-flare control device used to control emissions from batch process 
vents, you must establish emission profiles and conduct the test under 
worst-case conditions according to Sec.  63.1257(b)(8) instead of under 
normal operating conditions as specified in Sec.  63.7(e)(1) of subpart 
A or the conditions as specified in Sec.  63.2450(g)(6). The 
requirements in Sec.  63.997(e)(1)(i) and (iii) also do not apply for 
performance tests conducted to determine compliance with the emission 
limits for batch process vents. For purposes of this subpart, 
references in Sec.  63.997(b)(1) to ``methods specified in Sec.  
63.997(e)'' include the methods specified in Sec.  63.1257(b)(8).
* * * * *
    (v) If a process condenser is used for boiling operations in which 
HAP (not as an impurity) is heated to the boiling point, you must 
demonstrate that it is properly operated according to the procedures 
specified in Sec.  63.1257(d)(2)(i)(C)(4)(ii) and (d)(3)(iii)(B), and 
the demonstration

[[Page 49140]]

must occur only during the boiling operation. The reference in Sec.  
63.1257(d)(3)(iii)(B) to the alternative standard in Sec.  63.1254(c) 
means Sec.  63.2505 for the purposes of this subpart. As an alternative 
to measuring the exhaust gas temperature, as required by Sec.  
63.1257(d)(3)(iii)(B), you may elect to measure the liquid temperature 
in the receiver.
* * * * *
    (6) Outlet concentration correction for supplemental gases. If you 
use a control device other than a combustion device to comply with a 
TOC, organic HAP, or hydrogen halide and halogen HAP outlet 
concentration emission limit for batch process vents, you must correct 
the actual concentration for supplemental gases using Equation 1 to 
this paragraph (e)(6); you may use process knowledge and representative 
operating data to determine the fraction of the total flow due to 
supplemental gas.
* * * * *
    (9) Requirements for a biofilter. If you use a biofilter to meet 
either the 95-percent reduction requirement or outlet concentration 
requirement specified in Table 2 to this subpart, you must meet the 
requirements specified in paragraphs (c)(9)(i) through (vi) of this 
section.
* * * * *
    (ii) Performance tests. To demonstrate initial compliance, you must 
conduct a performance test according to the procedures in Sec. Sec.  
63.2450(g) and 63.997 of subpart SS, and paragraphs (c)(9)(ii)(A) 
through (D) of this section. The design evaluation option for small 
control devices is not applicable if you use a biofilter.
* * * * *
    (D) Before October 13, 2020, submit a performance test report as 
specified in Sec.  63.999(a)(2)(i) and (ii) and include the records 
from paragraph (c)(9)(ii)(B) of this section. Beginning on and after 
October 13, 2020, you must submit a performance test report as 
specified in Sec.  63.2520(f).
    (iii) Monitoring requirements. Use either a biofilter bed 
temperature monitoring device (or multiple devices) capable of 
providing a continuous record or an organic monitoring device capable 
of providing a continuous record. Comply with the requirements in Sec.  
63.2450(e)(4), the general requirements for monitoring in Sec.  63.996, 
and keep records of temperature or other parameter monitoring results 
as specified in Sec.  63.998(b) and (c), as applicable. If you monitor 
temperature, the operating temperature range must be based on only the 
temperatures measured during the performance test; these data may not 
be supplemented by engineering assessments or manufacturer's 
recommendations as otherwise allowed in Sec.  63.999(b)(3)(ii)(A). If 
you establish the operating range (minimum and maximum temperatures) 
using data from previous performance tests in accordance with Sec.  
63.996(c)(6), replacement of the biofilter media with the same type of 
media is not considered a process change under Sec.  63.997(b)(1). You 
may expand your biofilter bed temperature operating range by conducting 
a repeat performance test that demonstrates compliance with the 95-
percent reduction requirement or outlet concentration limit, as 
applicable.
    (iv) Repeat performance tests. You must conduct a repeat 
performance test using the applicable methods specified in Sec. Sec.  
63.2450(g) and 63.997 within 2 years following the previous performance 
test and within 150 days after each replacement of any portion of the 
biofilter bed media with a different type of media or each replacement 
of more than 50 percent (by volume) of the biofilter bed media with the 
same type of media.

0
8. Section 63.2465 is amended by revising paragraphs (c) introductory 
text and (d)(2) to read as follows:

Sec.  63.2465  What requirements must I meet for process vents that 
emit hydrogen halide and halogen HAP or HAP metals?

* * * * *
    (c) If collective uncontrolled hydrogen halide and halogen HAP 
emissions from the process vents within a process are greater than or 
equal to 1,000 pounds per year (lb/yr), you must comply with the 
requirements in Sec.  63.2450(e)(4) and the requirements of Sec.  
63.994 and the requirements referenced therein, except as specified in 
paragraphs (c)(1) through (3) of this section.
* * * * *
    (d) * * *
    (2) Conduct an initial performance test of each control device that 
is used to comply with the emission limit for HAP metals specified in 
Table 3 to this subpart. Conduct the performance test according to the 
procedures in Sec. Sec.  63.2450(g) and 63.997. Use Method 29 of 40 CFR 
part 60, appendix A, to determine the HAP metals at the inlet and 
outlet of each control device, or use Method 5 of 40 CFR part 60, 
appendix A, to determine the total particulate matter (PM) at the inlet 
and outlet of each control device. You may use ASTM D6784-02 
(Reapproved 2008) (incorporated by reference, see Sec.  63.14) as an 
alternative to Method 29 (portion for mercury only) as a method for 
measuring mercury concentrations of 0.5 to 100 micrograms per standard 
cubic meter. You have demonstrated initial compliance if the overall 
reduction of either HAP metals or total PM from the process is greater 
than or equal to 97 percent by weight.
* * * * *

0
9. Section 63.2470 is amended by revising paragraph (a), adding 
paragraph (b), revising paragraphs (c) and (e)(3), and adding paragraph 
(f) to read as follows:

Sec.  63.2470  What requirements must I meet for storage tanks?

    (a) General. You must meet each emission limit in Table 4 to this 
subpart that applies to your storage tanks, and except as specified in 
paragraph (b) of this section, you must also meet each applicable 
requirement specified in paragraphs (c) through (f) of this section and 
Sec. Sec.  63.2492 and 63.2493(a) through (c).
    (b) General for storage tanks in ethylene oxide service. On and 
after the compliance dates specified in Sec.  63.2445(i), paragraphs 
(d) and (e) of this section do not apply to storage tanks in ethylene 
oxide service as defined in Sec.  63.2550.
    (c) Exceptions to subparts SS and WW of this part. (1) Except as 
specified in paragraph (c)(4)(ii) of this section, if you conduct a 
performance test or design evaluation for a control device used to 
control emissions only from storage tanks, you must establish operating 
limits, conduct monitoring, and keep records using the same procedures 
as required in subpart SS of this part for control devices used to 
reduce emissions from process vents instead of the procedures specified 
in Sec. Sec.  63.985(c), 63.998(d)(2)(i), and 63.999(b)(2). You must 
also comply with the requirements in Sec.  63.2450(e)(4), as 
applicable.
    (2) Except as specified in paragraph (c)(4) of this section, when 
the term ``storage vessel'' is used in subparts SS and WW of this part, 
the term ``storage tank,'' as defined in Sec.  63.2550 applies for the 
purposes of this subpart.
    (3) For adsorbers that cannot be regenerated or regenerative 
adsorbers that are regenerated offsite, you must comply with the 
monitoring requirements in Sec.  63.2450(e)(7) in lieu of Sec.  
63.995(c).
    (4) Beginning no later than the compliance dates specified in Sec.  
63.2445(i), you must comply with paragraphs (c)(4)(i) and (ii) of this 
section.
    (i) The exemptions for ``vessels storing organic liquids that 
contain HAP only as impurities'' and ``pressure

[[Page 49141]]

vessels designed to operate in excess of 204.9 kilopascals and without 
emissions to the atmosphere'' listed in the definition of ``storage 
tank'' in Sec.  63.2550 do not apply for storage tanks in ethylene 
oxide service.
    (ii) For storage tanks in ethylene oxide service as defined in 
Sec.  63.2550, you may not use a design evaluation to determine the 
percent reduction of any control device that is used to comply with an 
emission limit specified in Table 4 to this subpart.
* * * * *
    (e) * * *
    (3) You may elect to set a pressure relief device to a value less 
than the 2.5 psig required in Sec.  63.1253(f)(5) if you provide 
rationale in your notification of compliance status report explaining 
why the alternative value is sufficient to prevent breathing losses at 
all times.
* * * * *
    (f) Storage tank degassing. Beginning no later than the compliance 
dates specified in Sec.  63.2445(g), for each storage tank subject to 
item 1 of Table 4 to this subpart, you must comply with paragraphs 
(f)(1) through (3) of this section during storage tank shutdown 
operations (i.e., emptying and degassing of a storage tank) until the 
vapor space concentration in the storage tank is less than 10 percent 
of the LEL. You must determine the LEL using process instrumentation or 
portable measurement devices and follow procedures for calibration and 
maintenance according to manufacturer's specifications.
    (1) Remove liquids from the storage tank as much as practicable.
    (2) Comply with one of the following:
    (i) Reduce emissions of total organic HAP by venting emissions 
through a closed vent system to a flare.
    (ii) Reduce emissions of total organic HAP by 95 weight-percent by 
venting emissions through a closed vent system to any combination of 
non-flare control devices.
    (iii) Reduce emissions of total organic HAP by routing emissions to 
a fuel gas system or process and meet the requirements specified in 
Sec.  63.982(d) and the applicable requirements in Sec.  63.2450(e)(4).
    (3) Maintain records necessary to demonstrate compliance with the 
requirements in Sec.  63.2450(u) including, if appropriate, records of 
existing standard site procedures used to empty and degas (deinventory) 
equipment for safety purposes.

0
10. Section 63.2475 is amended by revising paragraph (a) to read as 
follows:

Sec.  63.2475  What requirements must I meet for transfer racks?

    (a) You must comply with each emission limit and work practice 
standard in Table 5 to this subpart that applies to your transfer 
racks, and you must meet each applicable requirement in paragraph (b) 
of this section.
* * * * *

0
11. Section 63.2480 is amended by:
0
a. Revising paragraphs (a), (b) introductory text, and (b)(1), (2), and 
(5);
0
b. Adding paragraphs (b)(6) and (7);
0
c. Revising paragraphs (c) introductory text and (c)(5); and
0
d. Adding paragraphs (c)(10) and (11), (e), and (f).
    The revisions and additions read as follows:

Sec.  63.2480  What requirements must I meet for equipment leaks?

    (a) You must meet each requirement in Table 6 to this subpart that 
applies to your equipment leaks, except as specified in paragraphs (b) 
through (f) of this section. For each light liquid pump, valve, and 
connector in ethylene oxide service as defined in Sec.  63.2550(i), you 
must also meet the applicable requirements specified in Sec. Sec.  
63.2492 and 63.2493(d) and (e).
    (b) Except as specified in paragraphs (b)(6) and (7) of this 
section, if you comply with either subpart H or UU of this part, you 
may elect to comply with the provisions in paragraphs (b)(1) through 
(5) of this section as an alternative to the referenced provisions in 
subpart H or UU of this part.
    (1) The requirements for pressure testing in Sec.  63.178(b) or 
Sec.  63.1036(b) may be applied to all processes, not just batch 
processes.
    (2) For the purposes of this subpart, pressure testing for leaks in 
accordance with Sec.  63.178(b) or Sec.  63.1036(b) is not required 
after reconfiguration of an equipment train if flexible hose 
connections are the only disturbed equipment.
* * * * *
    (5) Except as specified in paragraph (b)(6) of this section, for 
pumps in light liquid service in an MCPU that has no continuous process 
vents and is part of an existing source, you may elect to consider the 
leak definition that defines a leak to be 10,000 parts per million 
(ppm) or greater as an alternative to the values specified in Sec.  
63.1026(b)(2)(i) through (iii) or Sec.  63.163(b)(2).
    (6) Beginning no later than the compliance dates specified in Sec.  
63.2445(h), paragraph (b)(5) of this section no longer applies.
    (7) For each piece of equipment that is subject to Table 6 to this 
subpart and is also subject to periodic monitoring with EPA Method 21 
of 40 CFR part 60, appendix A-7, and is added to an affected source 
after December 17, 2019, or replaces equipment at an affected source 
after December 17, 2019, you must initially monitor for leaks within 30 
days after August 12, 2020, or initial startup of the equipment, 
whichever is later. Equipment that is designated as unsafe- or 
difficult-to-monitor is not subject to this paragraph (b)(7).
    (c) Except as specified in paragraphs (c)(10) and (11) of this 
section, if you comply with 40 CFR part 65, subpart F, you may elect to 
comply with the provisions in paragraphs (c)(1) through (9) of this 
section as an alternative to the referenced provisions in 40 CFR part 
65, subpart F.
* * * * *
    (5) Except as specified in paragraph (c)(10) of this section, for 
pumps in light liquid service in an MCPU that has no continuous process 
vents and is part of an existing source, you may elect to consider the 
leak definition that defines a leak to be 10,000 ppm or greater as an 
alternative to the values specified in Sec.  65.107(b)(2)(i) through 
(iii) of this chapter.
* * * * *
    (10) Beginning no later than the compliance dates specified in 
Sec.  63.2445(h), paragraph (c)(5) of this section no longer applies.
    (11) For each piece of equipment that is subject to Table 6 to this 
subpart and is also subject to periodic monitoring with EPA Method 21 
of 40 CFR part 60, appendix A-7, and is added to an affected source 
after December 17, 2019, or replaces equipment at an affected source 
after December 17, 2019, you must initially monitor for leaks within 30 
days after August 12, 2020, or initial startup of the equipment, 
whichever is later. Equipment that is designated as unsafe- or 
difficult-to-monitor is not subject to this paragraph (c)(11).
* * * * *
    (e) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), except as specified in paragraph (e)(4) of this section, 
you must comply with the requirements specified in paragraphs (e)(1) 
and (2) of this section for pressure relief devices, such as relief 
valves or rupture disks, in organic HAP gas or vapor service instead of 
the pressure relief device requirements of Sec.  63.1030 of subpart UU, 
Sec.  63.165 of subpart H, or Sec.  65.111 of this chapter. Except as 
specified in paragraphs (e)(4) and (5) of this section, you must also 
comply with the requirements specified in paragraphs (e)(3), (6), (7), 
and (8) of this section for

[[Page 49142]]

all pressure relief devices in organic HAP service.
    (1) Operating requirements. Except during a pressure release, 
operate each pressure relief device in organic HAP gas or vapor service 
with an instrument reading of less than 500 ppm above background as 
measured by the method in Sec.  63.1023(b) of subpart UU, Sec.  
63.180(c) of subpart H, or Sec.  65.104(b) of this chapter.
    (2) Pressure release requirements. For pressure relief devices in 
organic HAP gas or vapor service, you must comply with the applicable 
requirements paragraphs (e)(2)(i) through (iii) of this section 
following a pressure release.
    (i) If the pressure relief device does not consist of or include a 
rupture disk, conduct instrument monitoring, as specified in Sec.  
63.1023(b) of subpart UU, Sec.  63.180(c) of subpart H, or Sec.  
65.104(b) of this chapter, no later than 5 calendar days after the 
pressure relief device returns to organic HAP gas or vapor service 
following a pressure release to verify that the pressure relief device 
is operating with an instrument reading of less than 500 ppm.
    (ii) If the pressure relief device includes a rupture disk, either 
comply with the requirements in paragraph (e)(2)(i) of this section 
(and do not replace the rupture disk) or install a replacement disk as 
soon as practicable after a pressure release, but no later than 5 
calendar days after the pressure release. You must conduct instrument 
monitoring, as specified in Sec.  63.1023(b) of subpart UU, Sec.  
63.180(c) of subpart H, or Sec.  65.104(b) of this chapter, no later 
than 5 calendar days after the pressure relief device returns to 
organic HAP gas or vapor service following a pressure release to verify 
that the pressure relief device is operating with an instrument reading 
of less than 500 ppm.
    (iii) If the pressure relief device consists only of a rupture 
disk, install a replacement disk as soon as practicable after a 
pressure release, but no later than 5 calendar days after the pressure 
release. You must not initiate startup of the equipment served by the 
rupture disk until the rupture disc is replaced. You must conduct 
instrument monitoring, as specified in Sec.  63.1023(b) of subpart UU, 
Sec.  63.180(c) of subpart H, or Sec.  65.104(b) of this chapter, no 
later than 5 calendar days after the pressure relief device returns to 
organic HAP gas or vapor service following a pressure release to verify 
that the pressure relief device is operating with an instrument reading 
of less than 500 ppm.
    (3) Pressure release management. Except as specified in paragraphs 
(e)(4) and (5) of this section, you must comply with the requirements 
specified in paragraphs (e)(3)(i) through (v) of this section for all 
pressure relief devices in organic HAP service.
    (i) You must equip each affected pressure relief device with a 
device(s) or use a monitoring system that is capable of:
    (A) Identifying the pressure release;
    (B) Recording the time and duration of each pressure release; and
    (C) Notifying operators immediately that a pressure release is 
occurring. The device or monitoring system must be either specific to 
the pressure relief device itself or must be associated with the 
process system or piping, sufficient to indicate a pressure release to 
the atmosphere. Examples of these types of devices and systems include, 
but are not limited to, a rupture disk indicator, magnetic sensor, 
motion detector on the pressure relief valve stem, flow monitor, or 
pressure monitor.
    (ii) You must apply at least three redundant prevention measures to 
each affected pressure relief device and document these measures. 
Examples of prevention measures include:
    (A) Flow, temperature, liquid level and pressure indicators with 
deadman switches, monitors, or automatic actuators. Independent, non-
duplicative systems within this category count as separate redundant 
prevention measures.
    (B) Documented routine inspection and maintenance programs and/or 
operator training (maintenance programs and operator training may count 
as only one redundant prevention measure).
    (C) Inherently safer designs or safety instrumentation systems.
    (D) Deluge systems.
    (E) Staged relief system where the initial pressure relief device 
(with lower set release pressure) discharges to a flare or other closed 
vent system and control device.
    (iii) If any affected pressure relief device releases to atmosphere 
as a result of a pressure release event, you must perform root cause 
analysis and corrective action analysis according to the requirement in 
paragraph (e)(6) of this section and implement corrective actions 
according to the requirements in paragraph (e)(7) of this section. You 
must also calculate the quantity of organic HAP released during each 
pressure release event and report this quantity as required in Sec.  
63.2520(e)(15). Calculations may be based on data from the pressure 
relief device monitoring alone or in combination with process parameter 
monitoring data and process knowledge.
    (iv) You must determine the total number of release events that 
occurred during the calendar year for each affected pressure relief 
device separately. You must also determine the total number of release 
events for each pressure relief device for which the root cause 
analysis concluded that the root cause was a force majeure event, as 
defined in Sec.  63.2550.
    (v) Except for pressure relief devices described in paragraphs 
(e)(4) and (5) of this section, the following release events from an 
affected pressure relief device are a deviation of the pressure release 
management work practice standards.
    (A) Any release event for which the root cause of the event was 
determined to be operator error or poor maintenance.
    (B) A second release event not including force majeure events from 
a single pressure relief device in a 3 calendar year period for the 
same root cause for the same equipment.
    (C) A third release event not including force majeure events from a 
single pressure relief device in a 3 calendar year period for any 
reason.
    (4) Pressure relief devices routed to a control device, process, 
fuel gas system, or drain system. (i) If all releases and potential 
leaks from a pressure relief device are routed through a closed vent 
system to a control device, back into the process, to the fuel gas 
system, or to a drain system, then you are not required to comply with 
paragraph (e)(1), (2), or (3) of this section.
    (ii) Before the compliance dates specified in Sec.  63.2445(g), 
both the closed vent system and control device (if applicable) 
referenced in paragraph (e)(4)(i) of this section must meet the 
applicable requirements specified in Sec.  63.982(b) and (c)(2) of 
subpart SS. Beginning no later than the compliance dates specified in 
Sec.  63.2445(g), both the closed vent system and control device (if 
applicable) referenced in paragraph (e)(4)(i) of this section must meet 
the applicable requirements specified in Sec. Sec.  63.982(c)(2), 
63.983, and 63.2450(e)(4) through (6).
    (iii) The drain system (if applicable) referenced in paragraph 
(e)(4)(i) must meet the applicable requirements specified in Sec.  
63.2485(e).
    (5) Pressure relief devices exempted from pressure release 
management requirements. The following types of pressure relief devices 
are not subject to the pressure release management requirements in 
paragraph (e)(3) of this section.
    (i) Pressure relief devices in heavy liquid service, as defined in 
Sec.  63.1020 of subpart UU or Sec.  65.103(f) of this chapter.
    (ii) Thermal expansion relief valves.

[[Page 49143]]

    (iii) Pressure relief devices on mobile equipment.
    (iv) Pilot-operated pressure relief devices where the primary 
release valve is routed through a closed vent system to a control 
device or back into the process, to the fuel gas system, or to a drain 
system.
    (v) Balanced bellows pressure relief devices where the primary 
release valve is routed through a closed vent system to a control 
device or back into the process, to the fuel gas system, or to a drain 
system.
    (6) Root cause analysis and corrective action analysis. A root 
cause analysis and corrective action analysis must be completed as soon 
as possible, but no later than 45 days after a release event. Special 
circumstances affecting the number of root cause analyses and/or 
corrective action analyses are provided in paragraphs (e)(6)(i) through 
(iii) of this section.
    (i) You may conduct a single root cause analysis and corrective 
action analysis for a single emergency event that causes two or more 
pressure relief devices installed on the same equipment to release.
    (ii) You may conduct a single root cause analysis and corrective 
action analysis for a single emergency event that causes two or more 
pressure relief devices to release, regardless of the equipment served, 
if the root cause is reasonably expected to be a force majeure event, 
as defined in Sec.  63.2550.
    (iii) Except as provided in paragraphs (e)(6)(i) and (ii) of this 
section, if more than one pressure relief device has a release during 
the same time period, an initial root cause analysis must be conducted 
separately for each pressure relief device that had a release. If the 
initial root cause analysis indicates that the release events have the 
same root cause(s), the initially separate root cause analyses may be 
recorded as a single root cause analysis and a single corrective action 
analysis may be conducted.
    (7) Corrective action implementation. You must conduct a root cause 
analysis and corrective action analysis as specified in paragraphs 
(e)(3)(iii) and (e)(6) of this section, and you must implement the 
corrective action(s) identified in the corrective action analysis in 
accordance with the applicable requirements in paragraphs (e)(7)(i) 
through (iii) of this section.
    (i) All corrective action(s) must be implemented within 45 days of 
the event for which the root cause and corrective action analyses were 
required or as soon thereafter as practicable. If you conclude that no 
corrective action should be implemented, you must record and explain 
the basis for that conclusion no later than 45 days following the 
event.
    (ii) For corrective actions that cannot be fully implemented within 
45 days following the event for which the root cause and corrective 
action analyses were required, you must develop an implementation 
schedule to complete the corrective action(s) as soon as practicable.
    (iii) No later than 45 days following the event for which a root 
cause and corrective action analyses were required, you must record the 
corrective action(s) completed to date, and, for action(s) not already 
completed, a schedule for implementation, including proposed 
commencement and completion dates.
    (8) Flowing pilot-operated pressure relief devices. For affected 
sources that commenced construction or reconstruction on or before 
December 17, 2019, you are prohibited from installing a flowing pilot-
operated pressure relief device or replacing any pressure relief device 
with a flowing pilot-operated pressure relief device after August 12, 
2023. For affected sources that commenced construction or 
reconstruction after December 17, 2019, you are prohibited from 
installing and operating flowing pilot-operated pressure relief 
devices. For purpose of compliance with this paragraph (e)(8), a 
flowing pilot-operated pressure relief device means the type of pilot-
operated pressure relief device where the pilot discharge vent 
continuously releases emissions to the atmosphere when the pressure 
relief device is actuated.
    (f) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), the referenced provisions specified in paragraphs (f)(1) 
through (18) of this section do not apply when demonstrating compliance 
with this section.
    (1) Section 63.163(c)(3) of subpart H.
    (2) Section 63.172(j)(3) of subpart H.
    (3) The second sentence of Sec.  63.181(d)(5)(i) of subpart H.
    (4) The phrase ``may be included as part of the startup, shutdown, 
and malfunction plan, as required by the referencing subpart for the 
source, or'' from Sec.  63.1024(f)(4)(i) of subpart UU.
    (5) Section 63.1026(b)(3) of subpart UU.
    (6) The phrase ``(except periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1026(e)(1)(ii)(A) of subpart UU.
    (7) The phrase ``(except during periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1028(e)(1)(i)(A) of subpart UU.
    (8) The phrase ``(except during periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1031(b)(1) of subpart UU.
    (9) The second sentence of Sec.  65.105(f)(4)(i) of this chapter.
    (10) Section 65.107(b)(3) of this chapter.
    (11) The phrase ``(except periods of start-up, shutdown, or 
malfunction)'' from Sec.  65.107(e)(1)(ii)(A) of this chapter.
    (12) The phrase ``(except during periods of start-up, shutdown, or 
malfunction)'' from Sec.  65.109(e)(1)(i)(A) of this chapter.
    (13) The phrase ``(except during periods of start-up, shutdown, or 
malfunction)'' from Sec.  65.112(b)(1) of this chapter.
    (14) The last sentence of Sec.  65.115(b)(1) of this chapter.
    (15) The last sentence of Sec.  65.115(b)(2) of this chapter.
    (16) The phrase ``Except for pressure relief devices needed for 
safety purposes, low leg drains, high point bleeds, analyzer vents, and 
open-ended valves or lines'' in Sec.  65.143(a)(3) of this chapter.
    (17) For flares complying with Sec.  63.2450(e)(5), the following 
provisions do not apply:
    (i) Section 63.172(d) of subpart H;
    (ii) Section 63.180(e) of subpart H;
    (iii) Section 63.181(g)(1)(iii) of subpart H;
    (iv) The phrase ``including periods when a flare pilot light system 
does not have a flame'' from Sec.  63.181(g)(2)(i) of subpart H;
    (v) Section 63.1034(b)(2)(iii) of subpart UU; and
    (vi) Section 65.115(b)(2) of this chapter.
    (18) For pressure relief devices complying with Sec.  63.2480(e), 
the following provisions are modified as follows:
    (i) In the introductory text of Sec.  63.180(c), replace the 
reference to Sec.  63.165(a) with Sec.  63.2480(e)(1).
    (ii) In Sec.  63.181(b)(2)(i), replace the reference to Sec.  
63.165(c) with Sec.  63.2480(e)(4).
    (iii) In Sec.  63.181(b)(2)(i), replace the reference to Sec.  
63.165(a) with Sec.  63.2480(e)(1).
    (iv) In Sec.  63.181(b)(3)(ii), replace the reference to Sec.  
63.165(d) with Sec.  63.2480(e)(2)(ii) and (iii).
    (v) In Sec.  63.181(f), replace the reference to Sec.  63.165(a) 
and (b) with Sec.  63.2480(e)(1) and (2).
    (vi) The information required to be reported under Sec.  
63.182(d)(2)(xiv) is now required to be reported under Sec.  
63.2520(e)(15)(i) through (iii).
    (vii) The reference to Sec.  63.1030(b) in Sec.  63.1021(a) no 
longer applies.

[[Page 49144]]

    (viii) In Sec.  63.1022(b)(2), replace the reference to Sec.  
63.1030(d) with Sec.  63.2480(e)(4).
    (ix) In Sec.  63.1022(b)(3), replace the reference to Sec.  
63.1030(e) with Sec.  63.2480(e)(2)(ii).
    (x) The reference to Sec.  63.1030(c) in Sec.  63.1022(a)(1)(v) no 
longer applies. Instead comply with the Sec.  63.2480(e)(1) and (2).
    (xi) In Sec.  63.1023(c) introductory text and (c)(4), replace the 
reference to Sec.  63.1030(b) with Sec.  63.2480(e)(1).
    (xii) In Sec.  63.1038(c) replace the reference to Sec.  
63.1030(c)(3) with Sec.  63.2480(e)(2).
    (xiii) The information required to be reported under Sec.  
63.1039(b)(4) is now required to be reported under Sec.  
63.2520(e)(15)(i) and (ii).
    (xiv) The reference to Sec.  65.111(b) of this chapter in Sec.  
65.102(a) of this chapter no longer applies.
    (xv) In Sec.  65.103(b)(3) of this chapter, replace the reference 
to Sec.  65.111(d) with Sec.  63.2480(e)(4).
    (xvi) In Sec.  65.103(b)(4) of this chapter, replace the reference 
to Sec.  63.111(e) with Sec.  63.2480(e)(2)(ii).
    (xvii) The reference to Sec.  65.111(b) and (c) of this chapter in 
Sec.  65.104(a)(1)(iv) of this chapter no longer applies. Instead 
comply with Sec.  63.2480(e)(1) and (2).
    (xviii) In Sec.  65.104(c) introductory text and (c)(4) of this 
chapter, replace the reference to Sec.  63.111(b) with Sec.  
63.2480(e)(1).
    (xix) In Sec.  65.119(c)(5) of this chapter, replace the reference 
to Sec.  65.111(c)(3) with Sec.  63.2480(e)(2) and replace the 
reference to Sec.  65.111(e) with Sec.  63.2480(e)(2)(ii) and (iii).
    (xx) The information required to be reported under Sec.  
65.120(b)(4) of this chapter is now required to be reported under Sec.  
63.2520(e)(15)(i) and (ii).

0
12. Section 63.2485 is amended by:
0
a. Revising paragraphs (a) and (f);
0
b. Adding paragraph (h)(4);
0
c. Revising paragraph (i)(2)(ii);
0
d. Adding paragraph (i)(2)(iii);
0
e. Revising paragraphs (k), the first sentence of (n)(2) introductory 
text, and (n)(2)(ii) and (n)(2)(iv)(A);
0
f. Adding paragraph (n)(2)(vii);
0
g. Revising paragraphs (n)(4) and (o); and
0
h. Adding paragraphs (p) and (q).
    The revisions and additions read as follows:

Sec.  63.2485  What requirements must I meet for wastewater streams and 
liquid streams in open systems within an MCPU?

    (a) General. You must meet each requirement in Table 7 to this 
subpart that applies to your wastewater streams and liquid streams in 
open systems within an MCPU, except as specified in paragraphs (b) 
through (q) of this section.
* * * * *
    (f) Closed-vent system requirements. Except as specified in Sec.  
63.2450(e)(6), when Sec.  63.148(k) refers to closed vent systems that 
are subject to the requirements of Sec.  63.172, the requirements of 
either Sec.  63.172 or Sec.  63.1034 apply for the purposes of this 
subpart.
* * * * *
    (h) * * *
    (4) As an alternative to using EPA Method 624 of 40 CFR part 136, 
appendix A, as specified in Sec.  63.144(b)(5)(i)(C), you may use ASTM 
D5790-95 (Reapproved 2012) (incorporated by reference, see Sec.  63.14) 
for the analysis of total organic HAP in wastewater samples. If you 
choose to use ASTM D5790-95 (Reapproved 2012), then you must also use 
the sampling procedures of EPA Method 25D 40 CFR part 60, appendix A-7, 
or an equivalent method.
    (i) * * *
    (2) * * *
    (ii) The transferee must treat the wastewater stream or residual in 
a biological treatment unit in accordance with the requirement in 
paragraph (i)(2)(iii) of this section and the requirements of 
Sec. Sec.  63.138 and 63.145 and the requirements referenced therein.
    (iii) Beginning no later than the compliance dates specified in 
Sec.  63.2445(g), the requirement of Sec.  63.145(a)(3) no longer 
applies. Instead, the transferee must comply with the conditions 
specified in Sec.  63.2450(g)(6).
* * * * *
    (k) Outlet concentration correction for supplemental gases. The 
requirement to correct outlet concentrations from combustion devices to 
3-percent oxygen in Sec. Sec.  63.139(c)(1)(ii) and 63.145(i)(6) 
applies only if supplemental gases are combined with a vent stream from 
a Group 1 wastewater stream. If emissions are controlled with a vapor 
recovery system as specified in Sec.  63.139(c)(2), you must correct 
for supplemental gases as specified in Sec.  63.2460(c)(6).
* * * * *
    (n) * * *
    (2) Calculate the destruction efficiency of the biological 
treatment unit using Equation 1 to this paragraph (n)(2) in accordance 
with the procedures described in paragraphs (n)(2)(i) through (viii) of 
this section. * * *
* * * * *
    (ii) Except as specified in paragraph (n)(2)(vii) of this section, 
conduct the demonstration under representative process unit and 
treatment unit operating conditions in accordance with Sec.  
63.145(a)(3) and (4).
* * * * *
    (iv) * * *
    (A) If the biological treatment process meets both of the 
requirements specified in Sec.  63.145(h)(1)(i) and (ii), you may elect 
to replace the Fbio term in Equation 1 to paragraph (n)(2) 
of this section with the numeral ``1.''
* * * * *
    (vii) Beginning no later than the compliance dates specified in 
Sec.  63.2445(g), the requirement of Sec.  63.145(a)(3) no longer 
applies. Instead, you must comply with the conditions specified in 
Sec.  63.2450(g)(6).
* * * * *
    (4) For any wastewater streams that are Group 1 for both PSHAP and 
SHAP, you may elect to meet the requirements specified in Table 7 to 
this subpart for the PSHAP and then comply with paragraphs (n)(1) 
through (3) of this section for the SHAP in the wastewater system. You 
may determine the SHAP mass removal rate, in kg/hr, in treatment units 
that are used to meet the requirements for PSHAP and add this amount to 
both the numerator and denominator in Equation 1 to paragraph (n)(2) of 
this section.
    (o) Compliance records. Except as specified in paragraph (p) of 
this section, for each CPMS used to monitor a nonflare control device 
for wastewater emissions, you must keep records as specified in Sec.  
63.998(c)(1) in addition to the records required in Sec.  63.147(d).
    (p) Compliance records after date of compliance. Beginning no later 
than the compliance dates specified in Sec.  63.2445(g), paragraph (o) 
of this section no longer applies. Instead, for each CPMS used to 
monitor a nonflare control device for wastewater emissions, you must 
keep records as specified in Sec.  63.998(c)(1) in addition to the 
records required in Sec.  63.147(d), except that the provisions of 
Sec.  63.998(c)(1)(ii)(D), (E), (F), and (G) do not apply.
    (q) Startup, shutdown, and malfunction referenced provisions. 
Beginning no later than the compliance dates specified in Sec.  
63.2445(g), the referenced provisions specified in paragraphs (q)(1) 
through (5) of this section do not apply when demonstrating compliance 
with this section.
    (1) Section 63.105(d) of subpart F and the phrase ``as part of the 
start-up, shutdown, and malfunction plan required under Sec.  
63.6(e)(3) of subpart A of this part'' from Sec.  63.105(e) of subpart 
F.
    (2) Section 63.132(b)(3)(i)(B) of subpart G.

[[Page 49145]]

    (3) The phrase ``or startup/shutdown/malfunction'' in Sec.  
63.132(f)(2) of subpart G.
    (4) Section 63.148(f)(3) of subpart G.
    (5) For flares complying with Sec.  63.2450(e)(5), the following 
provisions do not apply:
    (i) Section 63.139(c)(3) of subpart G;
    (ii) Section 63.139(d)(3) of subpart G;
    (iii) Section 63.145(j) of subpart G;
    (iv) Section 63.146(b)(7)(i) of subpart G; and
    (v) Section 63.147(d)(1) of subpart G.

0
13. Section 63.2490 is revised to read as follows:

Sec.  63.2490  What requirements must I meet for heat exchange systems?

    (a) You must comply with each requirement in Table 10 to this 
subpart that applies to your heat exchange systems, except as specified 
in paragraphs (b) through (d) of this section.
    (b) Except as specified in paragraph (d) of this section, if you 
comply with the requirements of Sec.  63.104 as specified in Table 10 
to this subpart, then the phrase ``a chemical manufacturing process 
unit meeting the conditions of Sec.  63.100 (b)(1) through (b)(3) of 
this subpart'' in Sec.  63.104(a) means ``an MCPU meeting the 
conditions of Sec.  63.2435'' for the purposes of this subpart.
    (c) Except as specified in paragraph (d) of this section, if you 
comply with the requirements of Sec.  63.104 as specified in Table 10 
to this subpart, then the reference to ``Sec.  63.100(c)'' in Sec.  
63.104(a) does not apply for the purposes of this subpart.
    (d) Unless one or more of the conditions specified in Sec.  
63.104(a)(1), (2), (5), and (6) are met, beginning no later than the 
compliance dates specified in Sec.  63.2445(g), the requirements of 
Sec.  63.104 as specified in Table 10 to this subpart and paragraphs 
(b) and (c) of this section no longer apply. Instead, you must monitor 
the cooling water for the presence of total strippable hydrocarbons 
that indicate a leak according to paragraph (d)(1) of this section, and 
if you detect a leak, then you must repair it according to paragraphs 
(d)(2) and (3) of this section, unless repair is delayed according to 
paragraph (d)(4) of this section. At any time before the compliance 
dates specified in Sec.  63.2445(g), you may choose to comply with the 
requirements in this paragraph (d) in lieu of the requirements of Sec.  
63.104 as specified in Table 10 to this subpart and paragraphs (b) and 
(c) of this section. The requirements in this paragraph (d) do not 
apply to heat exchange systems that have a maximum cooling water flow 
rate of 10 gallons per minute or less.
    (1) You must perform monitoring to identify leaks of total 
strippable hydrocarbons from each heat exchange system subject to the 
requirements of this subpart according to the procedures in paragraphs 
(d)(1)(i) through (v) of this section.
    (i) Monitoring locations for closed-loop recirculation heat 
exchange systems. For each closed loop recirculating heat exchange 
system, you must collect and analyze a sample from the location(s) 
described in either paragraph (d)(1)(i)(A) or (B) of this section.
    (A) Each cooling tower return line or any representative riser 
within the cooling tower prior to exposure to air for each heat 
exchange system.
    (B) Selected heat exchanger exit line(s), so that each heat 
exchanger or group of heat exchangers within a heat exchange system is 
covered by the selected monitoring location(s).
    (ii) Monitoring locations for once-through heat exchange systems. 
For each once-through heat exchange system, you must collect and 
analyze a sample from the location(s) described in paragraph 
(d)(1)(ii)(A) of this section. You may also elect to collect and 
analyze an additional sample from the location(s) described in 
paragraph (d)(1)(ii)(B) of this section.
    (A) Selected heat exchanger exit line(s), so that each heat 
exchanger or group of heat exchangers within a heat exchange system is 
covered by the selected monitoring location(s). The selected monitoring 
location may be at a point where discharges from multiple heat exchange 
systems are combined provided that the combined cooling water flow rate 
at the monitoring location does not exceed 40,000 gallons per minute.
    (B) The inlet water feed line for a once-through heat exchange 
system prior to any heat exchanger. If multiple heat exchange systems 
use the same water feed (i.e., inlet water from the same primary water 
source), you may monitor at one representative location and use the 
monitoring results for that sampling location for all heat exchange 
systems that use that same water feed.
    (iii) Monitoring method. If you comply with the total strippable 
hydrocarbon concentration leak action level as specified in paragraph 
(d)(1)(iv) of this section, you must comply with the requirements in 
paragraph (d)(1)(iii)(A) of this section. If you comply with the total 
hydrocarbon mass emissions rate leak action level as specified in 
paragraph (d)(1)(iv) of this section, you must comply with the 
requirements in paragraphs (d)(1)(iii)(A) and (B) of this section.
    (A) You must determine the total strippable hydrocarbon 
concentration (in parts per million by volume (ppmv) as methane) at 
each monitoring location using the ``Air Stripping Method (Modified El 
Paso Method) for Determination of Volatile Organic Compound Emissions 
from Water Sources'' (incorporated by reference--see Sec.  63.14) using 
a flame ionization detector (FID) analyzer for on-site determination as 
described in Section 6.1 of the Modified El Paso Method.
    (B) You must convert the total strippable hydrocarbon concentration 
(in ppmv as methane) to a total hydrocarbon mass emissions rate (as 
methane) using the calculations in Section 7.0 of ``Air Stripping 
Method (Modified El Paso Method) for Determination of Volatile Organic 
Compound Emissions from Water Sources'' (incorporated by reference--see 
Sec.  63.14).
    (iv) Monitoring frequency and leak action level. For each heat 
exchange system, you must initially monitor monthly for 6-months 
beginning upon startup and monitor quarterly thereafter using a leak 
action level defined as a total strippable hydrocarbon concentration 
(as methane) in the stripping gas of 6.2 ppmv or, for heat exchange 
systems with a recirculation rate of 10,000 gallons per minute or less, 
you may monitor quarterly using a leak action level defined as a total 
hydrocarbon mass emissions rate from the heat exchange system (as 
methane) of 0.18 kg/hr. If a leak is detected as specified in paragraph 
(d)(1)(v) of this section, then you must monitor monthly until the leak 
has been repaired according to the requirements in paragraph (d)(2) or 
(3) of this section. Once the leak has been repaired according to the 
requirements in paragraph (d)(2) or (3) of this section, quarterly 
monitoring for the heat exchange system may resume. The monitoring 
frequencies specified in this paragraph (d)(1)(iv) also apply to the 
inlet water feed line for a once-through heat exchange system, if 
monitoring of the inlet water feed is elected as provided in paragraph 
(d)(1)(ii)(B) of this section.
    (v) Leak definition. A leak is defined as described in paragraph 
(d)(1)(v)(A) or (B) of this section, as applicable.
    (A) For once-through heat exchange systems for which the inlet 
water feed is monitored as described in paragraph (d)(1)(ii)(B) of this 
section, a leak is detected if the difference in the measurement value 
of the sample taken from a location specified in paragraph

[[Page 49146]]

(d)(1)(ii)(A) of this section and the measurement value of the 
corresponding sample taken from the location specified in paragraph 
(d)(1)(ii)(B) of this section equals or exceeds the leak action level.
    (B) For all other heat exchange systems, a leak is detected if a 
measurement value of the sample taken from a location specified in 
paragraph (d)(1)(i)(A) or (B) or (d)(1)(ii)(A) of this section equals 
or exceeds the leak action level.
    (2) If a leak is detected using the methods described in paragraph 
(d)(1) of this section, you must repair the leak to reduce the 
concentration or mass emissions rate to below the applicable leak 
action level as soon as practicable, but no later than 45 days after 
identifying the leak, except as specified in paragraph (d)(4) of this 
section. Repair must include re-monitoring at the monitoring location 
where the leak was identified according to the method specified in 
paragraph (d)(1)(iii) of this section to verify that the total 
strippable hydrocarbon concentration or total hydrocarbon mass 
emissions rate is below the applicable leak action level. Repair may 
also include performing the additional monitoring in paragraph (d)(3) 
of this section to verify that the total strippable hydrocarbon 
concentration or total hydrocarbon mass emissions rate is below the 
applicable leak action level. Actions that can be taken to achieve 
repair include but are not limited to:
    (i) Physical modifications to the leaking heat exchanger, such as 
welding the leak or replacing a tube;
    (ii) Blocking the leaking tube within the heat exchanger;
    (iii) Changing the pressure so that water flows into the process 
fluid;
    (iv) Replacing the heat exchanger or heat exchanger bundle; or
    (v) Isolating, bypassing, or otherwise removing the leaking heat 
exchanger from service until it is otherwise repaired.
    (3) If you detect a leak when monitoring a cooling tower return 
line under paragraph (d)(1)(i)(A) of this section, you may conduct 
additional monitoring of each heat exchanger or group of heat 
exchangers associated with the heat exchange system for which the leak 
was detected, as provided in paragraph (d)(1)(i)(B) of this section. If 
no leaks are detected when monitoring according to the requirements of 
paragraph (d)(1)(i)(B) of this section, the heat exchange system is 
considered to have met the repair requirements through re-monitoring of 
the heat exchange system, as provided in paragraph (d)(2) of this 
section.
    (4) You may delay repair when one of the conditions in paragraph 
(d)(4)(i) or (ii) of this section is met and the leak is less than the 
delay of repair action level specified in paragraph (d)(4)(iii) of this 
section. You must determine if a delay of repair is necessary as soon 
as practicable, but no later than 45 days after first identifying the 
leak.
    (i) If the repair is technically infeasible without a shutdown and 
the total strippable hydrocarbon concentration or total hydrocarbon 
mass emissions rate is initially and remains less than the delay of 
repair action level for all monitoring periods during the delay of 
repair, then you may delay repair until the next scheduled shutdown of 
the heat exchange system. If, during subsequent monitoring, the delay 
of repair action level is exceeded, then you must repair the leak 
within 30 days of the monitoring event in which the leak was equal to 
or exceeded the delay of repair action level.
    (ii) If the necessary equipment, parts, or personnel are not 
available and the total strippable hydrocarbon concentration or total 
hydrocarbon mass emissions rate is initially and remains less than the 
delay of repair action level for all monitoring periods during the 
delay of repair, then you may delay the repair for a maximum of 120 
calendar days. You must demonstrate that the necessary equipment, 
parts, or personnel were not available. If, during subsequent 
monitoring, the delay of repair action level is exceeded, then you must 
repair the leak within 30 days of the monitoring event in which the 
leak was equal to or exceeded the delay of repair action level.
    (iii) The delay of repair action level is a total strippable 
hydrocarbon concentration (as methane) in the stripping gas of 62 ppmv 
or, for heat exchange systems with a recirculation rate of 10,000 
gallons per minute or less, the delay of repair action level is a total 
hydrocarbon mass emissions rate (as methane) or 1.8 kg/hr. The delay of 
repair action level is assessed as described in paragraph 
(d)(4)(iii)(A) or (B) of this section, as applicable.
    (A) For once-through heat exchange systems for which the inlet 
water feed is monitored as described in paragraph (d)(1)(ii)(B) of this 
section, the delay of repair action level is exceeded if the difference 
in the measurement value of the sample taken from a location specified 
in paragraph (d)(1)(ii)(A) of this section and the measurement value of 
the corresponding sample taken from the location specified in paragraph 
(d)(1)(ii)(B) of this section equals or exceeds the delay of repair 
action level.
    (B) For all other heat exchange systems, the delay of repair action 
level is exceeded if a measurement value of the sample taken from a 
location specified in paragraph (d)(1)(i)(A) or (B) or (d)(1)(ii)(A) of 
this section equals or exceeds the delay of repair action level.

0
14. Section 63.2492 is added to read as follows:

Sec.  63.2492  How do I determine whether my process vent, storage 
tank, or equipment is in ethylene oxide service?

    To determine if process vents, storage tanks, and equipment leaks 
are in ethylene oxide service as defined in Sec.  63.2550(i), you must 
comply with the requirements in paragraphs (a) through (c) of this 
section, as applicable.
    (a) For each batch process vent or continuous process vent stream, 
you must measure the flow rate and concentration of ethylene oxide of 
each process vent as specified in paragraphs (a)(1) through (5) of this 
section.
    (1) Measurements must be made prior to any dilution of the vent 
streams.
    (2) Measurements may be made on the combined vent streams at an 
MCPU or for each separate vent stream.
    (3) Method 1 or 1A of 40 CFR part 60, appendix A-1, as appropriate, 
must be used for the selection of the sampling sites. For vents smaller 
than 0.10 meter in diameter, sample at one point at the center of the 
duct.
    (4) The gas volumetric flow rate must be determined using Method 2, 
2A, 2C, 2D, 2F, or 2G of 40 CFR part 60, appendices A-1 and A-2, as 
appropriate.
    (5) The concentration of ethylene oxide must be determined using 
Method 18 of 40 CFR part 60, appendix A-6, or Method 320 of appendix A 
to this part.
    (b) For storage tanks, you must measure the concentration of 
ethylene oxide of the fluid stored in the storage tanks using Method 
624.1 of 40 CFR part 136, appendix A, or preparation by Method 5031 and 
analysis by Method 8260D (both incorporated by reference, see Sec.  
63.14) in the SW-846 Compendium. In lieu of preparation by SW-846 
Method 5031, you may use SW-846 Method 5030B (incorporated by 
reference, see Sec.  63.14), as long as: You do not use a preservative 
in the collected sample; you store the sample with minimal headspace as 
cold as possible and at least below 4 degrees C; and you analyze the 
sample as soon as possible, but in no case longer than 7 days from the 
time the sample was collected. If you are collecting a sample from a 
pressure vessel, you must maintain the sample under pressure both 
during and following sampling.

[[Page 49147]]

    (c) For equipment leaks, you must comply with the requirements in 
paragraphs (c)(1) through (4) of this section.
    (1) Each piece of equipment within an MCPU that can reasonably be 
expected to contain equipment in ethylene oxide service is presumed to 
be in ethylene oxide service unless you demonstrate that the piece of 
equipment is not in ethylene oxide service. For a piece of equipment to 
be considered not in ethylene oxide service, it must be determined that 
the percent ethylene oxide content of the process fluid that is 
contained in or contacts equipment can be reasonably expected to not 
exceed 0.1 percent by weight on an annual average basis. For purposes 
of determining the percent ethylene oxide content of the process fluid, 
you must use Method 18 of 40 CFR part 60, appendix A-6, for gaseous 
process fluid, and Method 624.1 of 40 CFR part 136, appendix A, or 
preparation by Method 5031 and analysis by Method 8260D (both 
incorporated by reference, see Sec.  63.14) in the SW-846 Compendium 
for liquid process fluid. In lieu of preparation by SW-846 Method 5031, 
you may use SW-846 Method 5030B (incorporated by reference, see Sec.  
63.14), as long as: You do not use a preservative in the collected 
sample; you store the sample with minimal headspace as cold as possible 
and at least below 4 degrees C; and you analyze the sample as soon as 
possible, but in no case longer than 7 days from the time the sample 
was collected.
    (2) Unless specified by the Administrator, you may use good 
engineering judgment rather than the procedures specified in paragraph 
(c)(1) of this section to determine that the percent ethylene oxide 
content of the process fluid that is contained in or contacts equipment 
does not exceed 0.1 percent by weight.
    (3) You may revise your determination for whether a piece of 
equipment is in ethylene oxide service by following the procedures in 
paragraph (c)(1) of this section, or by documenting that a change in 
the process or raw materials no longer causes the equipment to be in 
ethylene oxide service.
    (4) Samples used in determining the ethylene oxide content must be 
representative of the process fluid that is contained in or contacts 
the equipment.

0
15. Section 63.2493 is added to read as follows:

Sec.  63.2493  What requirements must I meet for process vents, storage 
tanks, or equipment that are in ethylene oxide service?

    This section applies beginning no later than the compliance dates 
specified in Sec.  63.2445(i). In order to demonstrate compliance with 
the emission limits and work practice standards specified in Tables 1, 
2, and 4 to this subpart for process vents and storage tanks in 
ethylene oxide service, you must meet the requirements specified in 
paragraphs (a) through (c) of this section. In order to demonstrate 
compliance with the requirements specified in Table 6 to this subpart 
for equipment in ethylene oxide service, you must meet the requirements 
specified in paragraphs (d) and (e) of this section.
    (a) Initial compliance. For initial compliance, you must comply 
with paragraphs (a)(1) through (4) of this section, as applicable.
    (1) If you choose to reduce emissions of ethylene oxide by venting 
emissions through a closed-vent system to a flare as specified in Table 
1, 2, or 4 to this subpart, then you must comply with Sec.  
63.2450(e)(4) and (6) and the requirements in Sec.  63.983, and you 
must conduct the initial visible emissions demonstration required by 
Sec.  63.670(h) of subpart CC as specified in Sec.  63.2450(e)(5).
    (2) If you choose to reduce emissions of ethylene oxide by venting 
emissions through a closed-vent system to a non-flare control device 
that reduces ethylene oxide by greater than or equal to 99.9 percent by 
weight as specified in Table 1, 2, or 4 to this subpart, then you must 
comply with Sec.  63.2450(e)(4) and (6) and the requirements in Sec.  
63.983, and you must comply with paragraphs (a)(2)(i) through (viii) of 
this section.
    (i) Conduct an initial performance test of the control device that 
is used to comply with the percent reduction requirement at the inlet 
and outlet of the control device. For purposes of compliance with this 
paragraph (a)(2), you may not use a design evaluation.
    (ii) Conduct the performance test according to the procedures in 
Sec. Sec.  63.997 and 63.2450(g). Use Method 18 of 40 CFR part 60, 
appendix A-6, or Method 320 of appendix A to this part to determine the 
ethylene oxide concentration. Use Method 1 or 1A of 40 CFR part 60, 
appendix A-1, to select the sampling sites at each sampling location. 
Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 
40 CFR part 60, appendix A-2. Use Method 4 of 40 CFR part 60, appendix 
A-3, to convert the volumetric flowrate to a dry basis.
    (iii) Calculate the mass emission rate of ethylene oxide entering 
the control device and exiting the control device using Equations 1 and 
2 to this paragraph (a)(2)(iii).

EEtO,inlet = K CEtO,inlet MEtO 
Qinlet (Eq. 1)
EEtO,outlet = K CEtO,outlet MEtO 
Qoutlet (Eq. 2)

Where:

EEtO,inlet, EEtO,outlet = Mass rate of 
ethylene oxide at the inlet and outlet of the control device, 
respectively, kilogram per hour.
CEtO,inlet, CEtO,outlet = Concentration of 
ethylene oxide in the gas stream at the inlet and outlet of the 
control device, respectively, dry basis, parts per million by 
volume.
MEtO = Molecular weight of ethylene oxide, 44.05 grams 
per gram-mole.
Qinlet, Qoutlet = Flow rate of the gas stream 
at the inlet and outlet of the control device, respectively, dry 
standard cubic meter per minute.
K = Constant, 2.494 x 10-6 (parts per million)-1 (gram-mole per 
standard cubic meter) (kilogram per gram) (minutes per hour), where 
standard temperature (gram-mole per standard cubic meter) is 20 
[deg]C.

    (iv) Calculate the percent reduction from the control device using 
Equation 3 to this paragraph (a)(2)(iv). You have demonstrated initial 
compliance if the overall reduction of ethylene oxide is greater than 
or equal to 99.9 percent by weight.

Percent reduction = (EEtO,inlet-EEtO,outlet)/
EEtO,inlet * 100 (Eq. 3)

Where:

EEtO,inlet, EEtO,outlet = Mass rate of 
ethylene oxide at the inlet and outlet of the control device, 
respectively, kilogram per hour, calculated using Equations 1 and 2 
to paragraph (a)(2)(iii) of this section.

    (v) If a new control device is installed, then conduct a 
performance test of the new device following the procedures in 
paragraphs (a)(2)(i) through (iv) of this section.
    (vi) If you vent emissions through a closed-vent system to a 
scrubber, then you must establish operating parameter limits by 
monitoring the operating parameters specified in paragraphs 
(a)(2)(vi)(A) through (C) of this section during the performance test.
    (A) Scrubber liquid-to-gas ratio (L/G), determined from the total 
scrubber liquid inlet flow rate and the exit gas flow rate. Determine 
the average L/G during the performance test as the average of the test 
run averages.
    (B) Scrubber liquid pH of the liquid in the reactant tank. The pH 
may be measured at any point between the discharge from the scrubber 
column and the inlet to the reactant tank. Determine the average pH 
during the performance test as the average of the test run averages.

[[Page 49148]]

    (C) Temperature of the water entering the scrubber column. The 
temperature may be measured at any point after the heat exchanger and 
prior to entering the top of the scrubber column. Determine the average 
inlet water temperature as the average of the test run averages.
    (vii) If you vent emissions through a closed-vent system to a 
thermal oxidizer, then you must establish operating parameter limits by 
monitoring the operating parameters specified in paragraphs 
(a)(2)(vii)(A) and (B) of this section during the performance test.
    (A) Combustion chamber temperature. Determine the average 
combustion chamber temperature during the performance test as the 
average of the test run averages.
    (B) Flue gas flow rate. Determine the average flue gas flow rate 
during the performance test as the average of the test run averages.
    (viii) If you vent emissions through a closed-vent system to a 
control device other than a flare, scrubber, or thermal oxidizer, then 
you must notify the Administrator of the operating parameters that you 
plan to monitor during the performance test prior to establishing 
operating parameter limits for the control device.
    (3) If you choose to reduce emissions of ethylene oxide by venting 
emissions through a closed-vent system to a non-flare control device 
that reduces ethylene oxide to less than 1 ppmv as specified in Table 
1, 2, or 4 to this subpart, then you must comply with Sec.  
63.2450(e)(4) and (6) and the requirements in Sec.  63.983, and you 
must comply with either paragraph (a)(3)(i) or (ii) of this section.
    (i) Install an FTIR CEMS meeting the requirements of Performance 
Specification 15 of 40 CFR part 60, appendix B, to continuously monitor 
the ethylene oxide concentration at the exit of the control device. 
Comply with the requirements specified in Sec.  63.2450(j) for your 
CEMS.
    (ii) If you do not install a CEMS under paragraph (a)(3)(i) of this 
section, you must comply with paragraphs (a)(3)(ii)(A) through (C) of 
this section.
    (A) Conduct an initial performance test of the control device that 
is used to comply with the concentration requirement at the outlet of 
the control device.
    (B) Conduct the performance test according to the procedures in 
Sec. Sec.  63.997 and 63.2450(g). Use Method 18 of 40 CFR part 60, 
appendix A-6, or Method 320 of appendix A to this part to determine the 
ethylene oxide concentration. You have demonstrated initial compliance 
if the ethylene oxide concentration is less than 1 ppmv.
    (C) Comply with the requirements specified in paragraphs (a)(2)(v) 
through (viii) of this section, as applicable.
    (4) If you choose to reduce emissions of ethylene oxide by venting 
emissions through a closed-vent system to a non-flare control device 
that reduces ethylene oxide to less than 5 pounds per year for all 
combined process vents as specified in Table 1 or 2 to this subpart, 
then you must comply with Sec.  63.2450(e)(4) and (6) and the 
requirements in Sec.  63.983, and you must comply with paragraphs 
(a)(4)(i) through (iv) of this section.
    (i) Conduct an initial performance test of the control device that 
is used to comply with the mass emission limit requirement at the 
outlet of the control device.
    (ii) Conduct the performance test according to the procedures in 
Sec. Sec.  63.997 and 63.2450(g). Use Method 18 of 40 CFR part 60, 
appendix A-6, or Method 320 of appendix A to this part to determine the 
ethylene oxide concentration. Use Method 1 or 1A of 40 CFR part 60, 
appendix A-1, to select the sampling site. Determine the gas volumetric 
flowrate using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A-2. 
Use Method 4 of 40 CFR part 60, appendix A-3, to convert the volumetric 
flowrate to a dry basis.
    (iii) Calculate the mass emission rate of ethylene oxide exiting 
the control device using Equation 2 to paragraph (a)(2)(iii) of this 
section. You have demonstrated initial compliance if the ethylene oxide 
from all process vents (controlled and uncontrolled) is less than 5 
pounds per year when combined.
    (iv) Comply with the requirements specified in paragraphs (a)(2)(v) 
through (viii) of this section, as applicable.
    (b) Continuous compliance. For continuous compliance, you must 
comply with paragraphs (b)(1) through (6) of this section, as 
applicable.
    (1) If you choose to reduce emissions of ethylene oxide by venting 
emissions through a closed-vent system to a flare as specified in Table 
1, 2, or 4 to this subpart, then you must comply with the requirements 
in Sec. Sec.  63.983 and 63.2450(e)(4) through (6).
    (2) Continuously monitor the ethylene oxide concentration at the 
exit of the control device using an FTIR CEMS meeting the requirements 
of Performance Specification 15 of 40 CFR part 60, appendix B, and 
Sec.  63.2450(j). If you use an FTIR CEMS, you do not need to conduct 
the performance testing required in paragraph (b)(3) of this section or 
the operating parameter monitoring required in paragraphs (b)(4) 
through (6) of this section.
    (3) Conduct a performance test no later than 60 months after the 
previous performance test and reestablish operating parameter limits 
following the procedures in paragraph (a)(2) through (4) of this 
section. The Administrator may request a repeat performance test at any 
time. For purposes of compliance with this paragraph (b)(3), you may 
not use a design evaluation.
    (4) If you vent emissions through a closed-vent system to a 
scrubber, then you must comply with Sec.  63.2450(e)(4) and (6) and the 
requirements in Sec.  63.983, and you must meet the operating parameter 
limits specified in paragraphs (b)(4)(i) through (v) of this section.
    (i) Minimum scrubber liquid-to-gas ratio (L/G), equal to the 
average L/G measured during the most recent performance test. Determine 
total scrubber liquid inlet flow rate with a flow sensor with a minimum 
accuracy of at least 5 percent over the normal range of 
flow measured, or 1.9 liters per minute (0.5 gallons per minute), 
whichever is greater. Determine exit gas flow rate with a flow sensor 
with a minimum accuracy of at least 5 percent over the 
normal range of flow measured, or 280 liters per minute (10 cubic feet 
per minute), whichever is greater. Compliance with the minimum L/G 
operating limit must be determined continuously on a 1-hour block 
basis.
    (ii) Maximum scrubber liquid pH of the liquid in the reactant tank, 
equal to the average pH measured during the most recent performance 
test. Compliance with the pH operating limit must be determined 
continuously on a 1-hour block basis. Use a pH sensor with a minimum 
accuracy of 0.2 pH units.
    (iii) Pressure drop across the scrubber column, within the pressure 
drop range specified by the manufacturer or established based on 
engineering analysis. Compliance with the pressure drop operating limit 
must be determined continuously on a 1-hour block basis. Use pressure 
sensors with a minimum accuracy of 5 percent over the 
normal operating range or 0.12 kilopascals, whichever is greater.
    (iv) Maximum temperature of the water entering the scrubber column, 
equal to the average temperature measured during the most recent 
performance test. Compliance with the inlet water temperature operating 
limit must be determined continuously on a 1-hour block basis. Use a 
temperature sensor with a minimum accuracy of 1 percent 
over the normal range of the temperature measured, expressed in

[[Page 49149]]

degrees Celsius, or 2.8 degrees Celsius, whichever is greater.
    (v) Liquid feed pressure to the scrubber column within the feed 
pressure range specified by the manufacturer or established based on 
engineering analysis. Compliance with the liquid feed pressure 
operating limit must be determined continuously on a 1-hour block 
basis. Use a pressure sensor with a minimum accuracy of 5 
percent over the normal operating range or 0.12 kilopascals, whichever 
is greater.
    (5) If you vent emissions through a closed-vent system to a thermal 
oxidizer, then you must comply with Sec.  63.2450(e)(4) and (6) and the 
requirements in Sec.  63.983, and you must meet the operating parameter 
limits specified in paragraphs (b)(5)(i) and (ii) of this section and 
the requirements in paragraph (b)(5)(iii) of this section.
    (i) Minimum combustion chamber temperature, equal to the average 
combustion chamber temperature measured during the most recent 
performance test. Determine combustion chamber temperature with a 
temperature sensor with a minimum accuracy of at least 1 
percent over the normal range of temperature measured, expressed in 
degrees Celsius, or 2.8 degrees Celsius, whichever is greater. 
Compliance with the minimum combustion chamber temperature operating 
limit must be determined continuously on a 1-hour block basis.
    (ii) Maximum flue gas flow rate, equal to the average flue gas flow 
rate measured during the most recent performance test. Determine flue 
gas flow rate with a flow sensor with a minimum accuracy of at least 
5 percent over the normal range of flow measured, or 280 
liters per minute (10 cubic feet per minute), whichever is greater. 
Compliance with the maximum flue gas flow rate operating limit must be 
determined continuously on a 1-hour block basis.
    (iii) You must maintain the thermal oxidizer in accordance with 
good combustion practices that ensure proper combustion. Good 
combustion practices include, but are not limited to, proper burner 
maintenance, proper burner alignment, proper fuel to air distribution 
and mixing, routine inspection, and preventative maintenance.
    (6) If you vent emissions through a closed-vent system to a control 
device other than a flare, scrubber, or thermal oxidizer, then you must 
comply with Sec.  63.2450(e)(4) and (6) and the requirements in Sec.  
63.983, and you must monitor the operating parameters identified in 
paragraph (a)(2)(viii) of this section and meet the established 
operating parameter limits to ensure continuous compliance. The 
frequency of monitoring and averaging time will be determined based 
upon the information provided to the Administrator.
    (c) Pressure vessels. If you have a storage tank in ethylene oxide 
service that is considered a pressure vessel as defined in as defined 
in Sec.  63.2550(i), then you must operate and maintain the pressure 
vessel, as specified in paragraphs (c)(1) through (5) of this section.
    (1) The pressure vessel must be designed to operate with no 
detectable emissions at all times.
    (2) Monitor each point on the pressure vessel through which 
ethylene oxide could potentially be emitted by conducting initial and 
annual performance tests using Method 21 of 40 CFR part 60, appendix A-
7.
    (3) Each instrument reading greater than 500 ppmv is a deviation.
    (4) Estimate the flow rate and total regulated material emissions 
from the defect. Assume the pressure vessel has been emitting for half 
of the time since the last performance test, unless other information 
supports a different assumption.
    (5) Whenever ethylene oxide is in the pressure vessel, you must 
operate the pressure vessel as a closed system that vents through a 
closed vent system to a control device as specified in paragraphs 
(c)(5)(i) through (iii) of this section, as applicable.
    (i) For closed vent systems, comply with Sec.  63.2450(e)(4) and 
(6) and the requirements in Sec.  63.983.
    (ii) For a non-flare control device, comply with requirements as 
specified in paragraph (b) of this section.
    (iii) For a flare, comply with the requirements of Sec.  
63.2450(e)(5).
    (d) Equipment in ethylene oxide service. Except as specified in 
paragraphs (d)(1) through (4) and (e) of this section, for equipment in 
ethylene oxide service as defined in Sec.  63.2550(i), you must comply 
with the requirements of subpart UU or H of this part, or 40 CFR part 
65, subpart F.
    (1) For pumps in ethylene oxide service, you must comply with the 
requirements in paragraphs (d)(1)(i) through (iii) of this section.
    (i) The instrument reading that defines a leak for pumps is 1,000 
parts per million or greater.
    (ii) The monitoring period for pumps is monthly.
    (iii) When a leak is detected, it must be repaired as soon as 
practicable, but not later than 15 calendar days after it is detected.
    (2) For connectors in ethylene oxide service, you must comply with 
the requirements in paragraphs (d)(2)(i) through (iii) of this section.
    (i) The instrument reading that defines a leak for connectors is 
500 parts per million or greater.
    (ii) The monitoring period for connectors is once every 12 months.
    (iii) When a leak is detected, it must be repaired as soon as 
practicable, but not later than 15 calendar days after it is detected.
    (3) For each light liquid pump or connector in ethylene oxide 
service that is added to an affected source, and for each light liquid 
pump or connector in ethylene oxide service that replaces a light 
liquid pump or connector in ethylene oxide service, you must initially 
monitor for leaks within 5 days after initial startup of the equipment.
    (4) Pressure relief devices in ethylene oxide service must comply 
with the requirements in Sec.  63.2480(e) and (f), except as specified 
in paragraphs (d)(4)(i) through (v) of this section.
    (i) The second sentence in Sec.  63.2480(e)(3)(iv) does not apply.
    (ii) Section 63.2480(e)(3)(v) does not apply.
    (iii) Section 63.2480(e)(6)(ii) does not apply.
    (iv) Any release event from an affected pressure relief device is a 
deviation of the pressure release management work practice standards.
    (v) Replace all references to Sec.  63.2445(g) with Sec.  
63.2445(h).
    (e) Non-applicable referenced provisions. The referenced provisions 
specified in paragraphs (e)(1) through (15) of this section do not 
apply when demonstrating compliance with this section.
    (1) Section 63.163(c)(3) of subpart H.
    (2) Section 63.163(e) of subpart H.
    (3) The second sentence of Sec.  63.181(d)(5)(i) of subpart H.
    (4) Section 63.1026(b)(3) of subpart UU.
    (5) Section 63.1026(e) of subpart UU.
    (6) The phrase ``(except during periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1028(e)(1)(i)(A) of subpart UU.
    (7) The phrase ``(except during periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1031(b)(1) of subpart UU.
    (8) The second sentence of Sec.  65.105(f)(4)(i) of this chapter.
    (9) Section 65.107(b)(3) of this chapter.
    (10) Section 65.107(e) of this chapter.
    (11) The phrase ``(except during periods of start-up, shutdown, or 
malfunction)'' from Sec.  65.109(e)(1)(i)(A) of this chapter.
    (12) The phrase ``(except during periods of start-up, shutdown, or

[[Page 49150]]

malfunction)'' from Sec.  65.112(b)(1) of this chapter.
    (13) The last sentence of Sec.  65.115(b)(1) of this chapter.
    (14) The last sentence of Sec.  65.115(b)(2) of this chapter.
    (15) For flares complying with Sec.  63.2450(e)(5), the following 
provisions do not apply:
    (i) Section 63.172(d) of subpart H;
    (ii) Section 63.180(e) of subpart H;
    (iii) Section 63.181(g)(1)(iii) of subpart H;
    (iv) The phrase ``including periods when a flare pilot light system 
does not have a flame'' from Sec.  63.181(g)(2)(i) of subpart H;
    (v) Section 63.1034(b)(2)(iii) of subpart H; and
    (vi) Section 65.115(b)(2) of this chapter.
    (16) Requirements for maintenance vents in Sec.  63.2450(v).

0
16. Section 63.2495 is amended by revising paragraph (b)(1) to read as 
follows:

Sec.  63.2495  How do I comply with the pollution prevention standard?

* * * * *
    (b) * * *
    (1) You must comply with the emission limitations and work practice 
standards contained in Tables 1 through 7 to this subpart for all HAP 
that are generated in the MCPU and that are not included in 
consumption, as defined in Sec.  63.2550. If any vent stream routed to 
the combustion control is a halogenated vent stream, as defined in 
Sec.  63.2550, then hydrogen halides that are generated as a result of 
combustion control must be controlled according to the requirements in 
Sec.  63.2450(e)(4) and the requirements of Sec.  63.994 and the 
requirements referenced therein.
* * * * *

0
17. Section 63.2500 is amended by revising paragraph (a) and adding 
paragraph (g) to read as follows:

Sec.  63.2500  How do I comply with emissions averaging?

    (a) For an existing source, you may elect to comply with the 
percent reduction emission limitations in Tables 1, 2, 4, 5, and 7 to 
this subpart by complying with the emissions averaging provisions 
specified in Sec.  63.150, except as specified in paragraphs (b) 
through (g) of this section.
* * * * *
    (g) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), Sec.  63.150(f)(2) does not apply when demonstrating 
compliance with this section.

0
18. Section 63.2505 is amended by revising paragraphs (b)(1) and 
(b)(6)(i) and (ii) to read as follows:

Sec.  63.2505  How do I comply with the alternative standard?

* * * * *
    (b) * * *
    (1) You must comply with the requirements in Sec.  63.2450(e)(4) 
and (6), and the requirements in Sec.  63.983 and the requirements 
referenced therein for closed-vent systems, except if you are not 
reducing organic HAP emissions by venting emissions through a closed-
vent system to any combination of control devices, including a flare or 
recovery device, you are not required to comply with the requirements 
in Sec.  63.983(b)(1)(i)(A), (b)(1)(ii), (c), (d)(1)(ii), and (d)(2) 
and (3).
* * * * *
    (6) * * *
    (i) Demonstrate initial compliance with the 95-percent reduction by 
conducting a performance test and setting a site-specific operating 
limit(s) for the scrubber in accordance with the requirements in Sec.  
63.2450(e)(4) and the requirements of Sec.  63.994 and the requirements 
referenced therein. You must submit the results of the initial 
compliance demonstration in the notification of compliance status 
report. If the performance test report is submitted electronically 
through the EPA's CEDRI in accordance with Sec.  63.2520(f), the 
process unit(s) tested, the pollutant(s) tested, and the date that such 
performance test was conducted may be submitted in the notification of 
compliance status report in lieu of the performance test results. The 
performance test results must be submitted to CEDRI by the date the 
notification of compliance status report is submitted.
    (ii) Install, operate, and maintain CPMS for the scrubber as 
specified in Sec. Sec.  63.994(c) and 63.2450(k), instead of as 
specified in Sec.  63.1258(b)(5)(i)(C). You must also comply with the 
requirements in Sec.  63.2450(e)(4), as applicable.
* * * * *

0
19. Section 63.2515 is amended by revising paragraph (a) and adding 
paragraph (d) to read as follows:

Sec.  63.2515  What notifications must I submit and when?

    (a) General. Except as specified in paragraph (d) of this section, 
you must submit all of the notifications in Sec. Sec.  63.6(h)(4) and 
(5), 63.7(b) and (c), 63.8(e) and (f)(4) and (6), and 63.9(b) through 
(h) of subpart A that apply to you by the dates specified.
* * * * *
    (d) Supplement to Notification of Compliance Status. You must also 
submit supplements to the Notification of Compliance Status as 
specified in Sec.  63.2520(d)(3) through (5).

0
20. Section 63.2520 is amended by:
0
a. Revising paragraphs (c) introductory text and (c)(2);
0
b. Adding paragraph (c)(8);
0
c. Revising paragraphs (d) introductory text and (d)(2)(ii);
0
d. Adding paragraphs (d)(3) through (5);
0
e. Revising paragraphs (e) introductory text, (e)(2) through (4), 
(e)(5)(ii) introductory text, and (e)(5)(ii)(A) and (B);
0
f. Adding paragraph (e)(5)(ii)(D);
0
g. Revising paragraphs (e)(5)(iii) introductory text and (e)(5)(iii)(A) 
through (F) and (I);
0
h. Adding paragraphs (e)(5)(iii)(M) and (N);
0
i. Revising paragraphs (e)(7), (8), and (9);
0
j. Revising paragraphs (e)(10) introductory text and (e)(10)(i); and
0
k. Adding paragraphs (e)(11) through (17) and (f) through (i).
    The revisions and additions read as follows:

Sec.  63.2520  What reports must I submit and when?

* * * * *
    (c) Precompliance report. You must submit a precompliance report to 
request approval for any of the items in paragraphs (c)(1) through (8) 
of this section. We will either approve or disapprove the report within 
90 days after we receive it. If we disapprove the report, you must 
still be in compliance with the emission limitations and work practice 
standards in this subpart by the compliance date. To change any of the 
information submitted in the report, you must notify us 60 days before 
the planned change is to be implemented.
* * * * *
    (2) Descriptions of daily or per batch demonstrations to verify 
that control devices subject to Sec.  63.2450(k)(6) are operating as 
designed.
* * * * *
    (8) For halogen reduction device other than a scrubber, procedures 
for establishing monitoring parameters as required by Sec.  
63.2450(e)(3)(ii).
    (d) Notification of compliance status report. You must submit a 
notification of compliance status report according to the schedule in 
paragraph (d)(1) of this section, and the notification of compliance 
status report must contain the information specified in paragraphs 
(d)(2) through (5) of this section.
* * * * *

[[Page 49151]]

    (2) * * *
    (ii) The results of emissions profiles, performance tests, 
engineering analyses, design evaluations, flare compliance assessments, 
inspections and repairs, and calculations used to demonstrate initial 
compliance according to Sec. Sec.  63.2455 through 63.2485. For 
performance tests, results must include descriptions of sampling and 
analysis procedures and quality assurance procedures. If the 
performance test report is submitted electronically through the EPA's 
CEDRI in accordance with paragraph (f) of this section, the process 
unit(s) tested, the pollutant(s) tested, and the date that such 
performance test was conducted may be submitted in the notification of 
compliance status report in lieu of the performance test results. The 
performance test results must be submitted to CEDRI by the date the 
notification of compliance status report is submitted.
* * * * *
    (3) For flares subject to the requirements of Sec.  63.2450(e)(5), 
you must also submit the information in this paragraph (d)(3) in a 
supplement to the Notification of Compliance Status within 150 days 
after the first applicable compliance date for flare monitoring. In 
lieu of the information required in Sec.  63.987(b) of subpart SS, the 
supplement to the Notification of Compliance Status must include flare 
design (e.g., steam-assisted, air-assisted, non-assisted, or pressure-
assisted multi-point); all visible emission readings, heat content 
determinations, flow rate measurements, and exit velocity 
determinations made during the initial visible emissions demonstration 
required by Sec.  63.670(h) of subpart CC, as applicable; and all 
periods during the compliance determination when the pilot flame or 
flare flame is absent.
    (4) For pressure relief devices subject to the pressure release 
management work practice standards in Sec.  63.2480(e)(3), you must 
also submit the information listed in paragraphs (d)(4)(i) and (ii) of 
this section in a supplement to the Notification of Compliance Status 
within 150 days after the first applicable compliance date for pressure 
relief device monitoring.
    (i) A description of the monitoring system to be implemented, 
including the relief devices and process parameters to be monitored, 
and a description of the alarms or other methods by which operators 
will be notified of a pressure release.
    (ii) A description of the prevention measures to be implemented for 
each affected pressure relief device.
    (5) For process vents, storage tanks, and equipment leaks subject 
to the requirements of Sec.  63.2493, you must also submit the 
information in this paragraph (d)(5) in a supplement to the 
Notification of Compliance Status within 150 days after the first 
applicable compliance date. The supplement to the Notification of 
Compliance Status must identify all process vents, storage tanks, and 
equipment that are in ethylene oxide service as defined in Sec.  
63.2550, the method(s) used to control ethylene oxide emissions from 
each process vent and storage tank (i.e., use of a flare, scrubber, or 
other control device), the method(s) used to control ethylene oxide 
emissions from equipment (i.e., subpart UU or H of this part, or 40 CFR 
part 65, subpart F), and the information specified in paragraphs 
(d)(5)(i) through (iii) of this section.
    (i) For process vents, include all uncontrolled, undiluted ethylene 
oxide concentration measurements, and the calculations you used to 
determine the total uncontrolled ethylene oxide mass emission rate for 
the sum of all vent gas streams.
    (ii) For storage tanks, include the concentration of ethylene oxide 
of the fluid stored in each storage tank.
    (iii) For equipment, include the percent ethylene oxide content of 
the process fluid and the method used to determine it.
    (e) Compliance report. The compliance report must contain the 
information specified in paragraphs (e)(1) through (17) of this 
section. On and after August 12, 2023 or once the reporting template 
for this subpart has been available on the CEDRI website for 1 year, 
whichever date is later, you must submit all subsequent reports to the 
EPA via the CEDRI, which can be accessed through the EPA's CDX (https://cdx.epa.gov/). The EPA will make all the information submitted through 
CEDRI available to the public without further notice to you. Do not use 
CEDRI to submit information you claim as CBI. Anything submitted using 
CEDRI cannot later be claimed to be CBI. You must use the appropriate 
electronic report template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/compliance-and-emissions-data-reporting-interface-cedri) for this subpart. The date report templates 
become available will be listed on the CEDRI website. Unless the 
Administrator or delegated state agency or other authority has approved 
a different schedule for submission of reports under Sec. Sec.  63.9(i) 
and 63.10(a) of subpart A, the report must be submitted by the deadline 
specified in this subpart, regardless of the method in which the report 
is submitted. Although we do not expect persons to assert a claim of 
CBI, if you wish to assert a CBI claim, submit a complete report, 
including information claimed to be CBI, to the EPA. The report must be 
generated using the appropriate form on the CEDRI website or an 
alternate electronic file consistent with the extensible markup 
language (XML) schema listed on the CEDRI website. Submit the file on a 
compact disc, flash drive, or other commonly used electronic storage 
medium and clearly mark the medium as CBI. Mail the electronic medium 
to U.S. Environmental Protection Agency, Office of Air Quality Planning 
and Standards, Sector Policies and Programs Division, CORE CBI Office, 
U.S. EPA Mailroom (C404-02), Attention: Miscellaneous Organic Chemical 
Manufacturing Sector Lead, 4930 Old Page Rd., Durham, NC 27703. The 
same file with the CBI omitted must be submitted to the EPA via the 
EPA's CDX as described in this paragraph (e). All CBI claims must be 
asserted at the time of submission. Furthermore under CAA section 
114(c) emissions data is not entitled to confidential treatment, and 
the EPA is required to make emissions data available to the public. 
Thus, emissions data will not be protected as CBI and will be made 
publicly available. You may assert a claim of EPA system outage or 
force majeure for failure to timely comply with the reporting 
requirement in this paragraph (e) provided you meet the requirements 
outlined in paragraph (i) or (j) of this section, as applicable.
* * * * *
    (2) Statement by a responsible official with that official's name, 
title, and signature, certifying the accuracy of the content of the 
report. If your report is submitted via CEDRI, the certifier's 
electronic signature during the submission process replaces the 
requirement in this paragrpah (e)(2).
    (3) Date of report and beginning and ending dates of the reporting 
period. You are no longer required to provide the date of report when 
the report is submitted via CEDRI.
    (4) For each SSM during which excess emissions occur, the 
compliance report must include records that the procedures specified in 
your startup, shutdown, and malfunction plan (SSMP) were followed or 
documentation of actions taken that are not consistent with the SSMP, 
and include a brief description of each malfunction. On and after 
August 12, 2023, this paragraph (e)(4) no longer

[[Page 49152]]

applies; however, for historical compliance purposes, a copy of the 
plan must be retained and available on-site for five years after August 
12, 2023.
    (5) * * *
    (ii) For each deviation from an emission limit, operating limit, 
and work practice standard that occurs at an affected source where you 
are not using a continuous monitoring system (CMS) to comply with the 
emission limit or work practice standard in this subpart, you must 
include the information in paragraphs (e)(5)(ii)(A) through (D) of this 
section. This includes periods of SSM.
    (A) The total operating time in hours of the affected source during 
the reporting period.
    (B) Except as specified in paragraph (e)(5)(ii)(D) of this section, 
information on the number, duration, and cause of deviations (including 
unknown cause, if applicable), as applicable, and the corrective action 
taken.
* * * * *
    (D) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), paragraph (e)(5)(ii)(B) of this section no longer applies. 
Instead, report information for each deviation to meet an applicable 
standard. For each instance, report the start date, start time, and 
duration in hours of each deviation. For each deviation, the report 
must include a list of the affected sources or equipment, an estimate 
of the quantity in pounds of each regulated pollutant emitted over any 
emission limit, a description of the method used to estimate the 
emissions, the cause of the deviation (including unknown cause, if 
applicable), as applicable, and the corrective action taken.
    (iii) For each deviation from an emission limit or operating limit 
occurring at an affected source where you are using a CMS to comply 
with an emission limit in this subpart, you must include the 
information in paragraphs (e)(5)(iii)(A) through (N) of this section. 
This includes periods of SSM.
    (A) The start date, start time, and duration in hours that each CMS 
was inoperative, except for zero (low-level) and high-level checks.
    (B) The start date, start time, and duration in hours that each 
CEMS was out-of-control and a description of the corrective actions 
taken.
    (C) Except as specified in paragraph (e)(5)(iii)(M) of this 
section, the date and time that each deviation started and stopped, and 
whether each deviation occurred during a period of startup, shutdown, 
or malfunction or during another period.
    (D) The total duration in hours of all deviations for each CMS 
during the reporting period, the total operating time in hours of the 
affected source during the reporting period, and the total duration as 
a percent of the total operating time of the affected source during 
that reporting period.
    (E) Except as specified in paragraph (e)(5)(iii)(N) of this 
section, a breakdown of the total duration of the deviations during the 
reporting period into those that are due to startup, shutdown, control 
equipment problems, process problems, other known causes, and other 
unknown causes.
    (F) The total duration in hours of CMS downtime for each CMS during 
the reporting period, and the total duration of CMS downtime as a 
percent of the total operating time of the affected source during that 
reporting period.
* * * * *
    (I) The monitoring equipment manufacturer(s) and model number(s) 
and the pollutant or parameter monitored.
* * * * *
    (M) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), paragraph (e)(5)(iii)(C) of this section no longer applies. 
Instead, report the number of deviation to meet an applicable standard. 
For each instance, report the start date, start time and duration in 
hours of each deviation. For each deviation, the report must include a 
list of the affected sources or equipment, an estimate of the quantity 
in pounds of each regulated pollutant emitted over any emission limit, 
a description of the method used to estimate the emissions, and the 
cause of the deviation (including unknown cause, if applicable), as 
applicable, and the corrective action taken.
    (N) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), paragraph (e)(5)(iii)(E) of this section no longer applies. 
Instead, report a breakdown of the total duration in hours of the 
deviations during the reporting period into those that are due control 
equipment problems, process problems, other known causes, and other 
unknown causes.
* * * * *
    (7) Include each new operating scenario which has been operated 
since the time period covered by the last compliance report and has not 
been submitted in the notification of compliance status report or a 
previous compliance report. For each new operating scenario, you must 
report the information specified in Sec.  63.2525(b) and provide 
verification that the operating conditions for any associated control 
or treatment device have not been exceeded and that any required 
calculations and engineering analyses have been performed. For the 
purposes of this paragraph (e)(7), a revised operating scenario for an 
existing process is considered to be a new operating scenario.
    (8) For process units added to a PUG, you must report the 
description and rationale specified in Sec.  63.2525(i)(4). You must 
report your primary product redeterminations specified in Sec.  
63.2525(i)(5).
    (9) Except as specified in Sec. Sec.  63.2450(e)(4), 63.2480(f), 
and 63.2485(p) and (q) and paragraph (t) of this section, applicable 
records and information for periodic reports as specified in referenced 
subparts F, G, H, SS, UU, WW, and GGG of this part and subpart F of 40 
CFR part 65.
    (10) Except as specified in paragraph (e)(10)(ii) of this section, 
whenever you make a process change, or change any of the information 
submitted in the notification of compliance status report or a previous 
compliance report, that is not within the scope of an existing 
operating scenario, you must document the change in your compliance 
report. A process change does not include moving within a range of 
conditions identified in the standard batch, and a nonstandard batch 
does not constitute a process change.
    (i) The notification must include all of the information in 
paragraphs (e)(10)(i)(A) through (C) of this section.
    (A) A description of the process change.
    (B) Revisions to any of the information reported in the original 
notification of compliance status report under paragraph (d) of this 
section.
    (C) Information required by the notification of compliance status 
report under paragraph (d) of this section for changes involving the 
addition of processes or equipment at the affected source.
    (ii) You must submit a report 60 days before the scheduled 
implementation date of any of the changes identified in paragraph 
(e)(10)(ii)(A), (B), or (C) of this section.
    (A) Any change to the information contained in the precompliance 
report.
    (B) A change in the status of a control device from small to large.
    (C) A change from Group 2 to Group 1 for any emission point except 
for batch process vents that meet the conditions specified in Sec.  
63.2460(b)(6)(i).
    (11) For each flare subject to the requirements in Sec.  
63.2450(e)(5), the compliance report must include the items specified 
in paragraphs (e)(11)(i) through (vi) of this section in lieu of the

[[Page 49153]]

information required in Sec.  63.999(c)(3) of subpart SS.
    (i) Records as specified in Sec.  63.2525(m)(1) for each 15-minute 
block during which there was at least one minute when regulated 
material is routed to a flare and no pilot flame or flare flame is 
present. Include the start and stop time and date of each 15-minute 
block.
    (ii) Visible emission records as specified in Sec.  
63.2525(m)(2)(iv) for each period of 2 consecutive hours during which 
visible emissions exceeded a total of 5 minutes.
    (iii) The periods specified in Sec.  63.2525(m)(6). Indicate the 
date and start and end times for each period, and the net heating value 
operating parameter(s) determined following the methods in Sec.  
63.670(k) through (n) of subpart CC as applicable.
    (iv) For flaring events meeting the criteria in Sec. Sec.  
63.670(o)(3) of subpart CC and 63.2450(e)(5)(v):
    (A) The start and stop time and date of the flaring event.
    (B) The length of time in minutes for which emissions were visible 
from the flare during the event.
    (C) For steam-assisted, air-assisted, and non-assisted flares, the 
start date, start time, and duration in minutes for periods of time 
that the flare tip velocity exceeds the maximum flare tip velocity 
determined using the methods in Sec.  63.670(d)(2) of subpart CC and 
the maximum 15-minute block average flare tip velocity in ft/sec 
recorded during the event.
    (D) Results of the root cause and corrective actions analysis 
completed during the reporting period, including the corrective actions 
implemented during the reporting period and, if applicable, the 
implementation schedule for planned corrective actions to be 
implemented subsequent to the reporting period.
    (v) For pressure-assisted multi-point flares, the periods of time 
when the pressure monitor(s) on the main flare header show the burners 
operating outside the range of the manufacturer's specifications. 
Indicate the date and start and end times for each period.
    (vi) For pressure-assisted multi-point flares, the periods of time 
when the staging valve position indicator monitoring system indicates a 
stage should not be in operation and is or when a stage should be in 
operation and is not. Indicate the date and start and end times for 
each period.
    (12) For bypass lines subject to the requirements Sec.  
63.2450(e)(6), the compliance report must include the start date, start 
time, duration in hours, estimate of the volume of gas in standard 
cubic feet, the concentration of organic HAP in the gas in parts per 
million by volume and the resulting mass emissions of organic HAP in 
pounds that bypass a control device. For periods when the flow 
indicator is not operating, report the start date, start time, and 
duration in hours.
    (13) For each nonregenerative adsorber and regenerative adsorber 
that is regenerated offsite subject to the requirements in Sec.  
63.2450(e)(7), you must report the date of each instance when 
breakthrough, as defined in Sec.  63.2550(i), is detected between the 
first and second adsorber and the adsorber is not replaced according to 
Sec.  63.2450(e)(7)(iii)(A).
    (14) For any maintenance vent release exceeding the applicable 
limits in Sec.  63.2450(v)(1), the compliance report must include the 
information specified in paragraphs (e)(14)(i) through (iv) of this 
section. For the purposes of this reporting requirement, if you comply 
with Sec.  63.2450(v)(1)(iv) then you must report each venting event 
conducted under those provisions and include an explanation for each 
event as to why utilization of this alternative was required.
    (i) Identification of the maintenance vent and the equipment served 
by the maintenance vent.
    (ii) The date and time the maintenance vent was opened to the 
atmosphere.
    (iii) The lower explosive limit in percent, vessel pressure in 
psig, or mass in pounds of VOC in the equipment, as applicable, at the 
start of atmospheric venting. If the 5 psig vessel pressure option in 
Sec.  63.2450(v)(1)(ii) was used and active purging was initiated while 
the lower explosive limit was 10 percent or greater, also include the 
lower explosive limit of the vapors at the time active purging was 
initiated.
    (iv) An estimate of the mass in pounds of organic HAP released 
during the entire atmospheric venting event.
    (15) Compliance reports for pressure relief devices subject to the 
requirements Sec.  63.2480(e) must include the information specified in 
paragraphs (e)(15)(i) through (iii) of this section.
    (i) For pressure relief devices in organic HAP gas or vapor 
service, pursuant to Sec.  63.2480(e)(1), report the instrument 
readings and dates for all readings of 500 ppmv or greater.
    (ii) For pressure relief devices in organic HAP gas or vapor 
service subject to Sec.  63.2480(e)(2), report the instrument readings 
and dates of instrument monitoring conducted.
    (iii) For pressure relief devices in organic HAP service subject to 
Sec.  63.2480(e)(3), report each pressure release to the atmosphere, 
including the start date, start time, and duration in minutes of the 
pressure release and an estimate of the mass quantity in pounds of each 
organic HAP released; the results of any root cause analysis and 
corrective action analysis completed during the reporting period, 
including the corrective actions implemented during the reporting 
period; and, if applicable, the implementation schedule for planned 
corrective actions to be implemented subsequent to the reporting 
period.
    (16) For each heat exchange system subject to Sec.  63.2490(d), 
beginning no later than the compliance dates specified in Sec.  
63.2445(g), the reporting requirements of Sec.  63.104(f)(2) no longer 
apply; instead, the compliance report must include the information 
specified in paragraphs (e)(16)(i) through (v) of this section.
    (i) The number of heat exchange systems at the plant site subject 
to the monitoring requirements in Sec.  63.2490(d) during the reporting 
period;
    (ii) The number of heat exchange systems subject to the monitoring 
requirements in Sec.  63.2490(d) at the plant site found to be leaking 
during the reporting period;
    (iii) For each monitoring location where the total strippable 
hydrocarbon concentration or total hydrocarbon mass emissions rate was 
determined to be equal to or greater than the applicable leak 
definitions specified in Sec.  63.2490(d)(1)(v) during the reporting 
period, identification of the monitoring location (e.g., unique 
monitoring location or heat exchange system ID number), the measured 
total strippable hydrocarbon concentration or total hydrocarbon mass 
emissions rate, the date the leak was first identified, and, if 
applicable, the date the source of the leak was identified;
    (iv) For leaks that were repaired during the reporting period 
(including delayed repairs), identification of the monitoring location 
associated with the repaired leak, the total strippable hydrocarbon 
concentration or total hydrocarbon mass emissions rate measured during 
re-monitoring to verify repair, and the re-monitoring date (i.e., the 
effective date of repair); and
    (v) For each delayed repair, identification of the monitoring 
location associated with the leak for which repair is delayed, the date 
when the delay of repair began, the date the repair is expected to be 
completed (if the leak is not repaired during the reporting period), 
the total strippable hydrocarbon concentration or total hydrocarbon 
mass emissions rate and date of each monitoring event conducted on the

[[Page 49154]]

delayed repair during the reporting period, and an estimate in pounds 
of the potential total hydrocarbon emissions over the reporting period 
associated with the delayed repair.
    (17) For process vents and storage tanks in ethylene oxide service 
subject to the requirements of Sec.  63.2493, the compliance report 
must include:
    (i) The periods specified in Sec.  63.2525(s)(4). Indicate the date 
and start and end times for each period.
    (ii) If you obtain an instrument reading greater than 500 ppmv of a 
leak when monitoring a pressure vessel in accordance with Sec.  
63.2493(c)(2), submit a copy of the records specified in Sec.  
63.2525(s)(5)(ii).
    (iii) Reports for equipment subject to the requirements of Sec.  
63.2493 as specified in paragraph (e)(9) of this section.
    (f) Performance test reports. Beginning no later than October 13, 
2020, you must submit performance test reports in accordance with this 
paragraph (f). Unless otherwise specified in this subpart, within 60 
days after the date of completing each performance test required by 
this subpart, you must submit the results of the performance test 
following the procedures specified in paragraphs (f)(1) through (3) of 
this section.
    (1) Data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT website 
(https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test. Submit the results of the 
performance test to the EPA via CEDRI, which can be accessed through 
the EPA's CDX (https://cdx.epa.gov/). The data must be submitted in a 
file format generated through the use of the EPA's ERT. Alternatively, 
you may submit an electronic file consistent with the extensible markup 
language (XML) schema listed on the EPA's ERT website.
    (2) Data collected using test methods that are not supported by the 
EPA's ERT as listed on the EPA's ERT website at the time of the test. 
The results of the performance test must be included as an attachment 
in the ERT or an alternate electronic file consistent with the XML 
schema listed on the EPA's ERT website. Submit the ERT generated 
package or alternative file to the EPA via CEDRI.
    (3) Confidential business information (CBI). The EPA will make all 
the information submitted through CEDRI available to the public without 
further notice to you. Do not use CEDRI to submit information you claim 
as CBI. Anything submitted using CEDRI cannot later be claimed to be 
CBI. Although we do not expect persons to assert a claim of CBI, if you 
wish to assert a CBI claim, you must submit a complete file, including 
information claimed to be CBI, to the EPA. The file must be generated 
through the use of the EPA's ERT or an alternate electronic file 
consistent with the XML schema listed on the EPA's ERT website. Submit 
the file on a compact disc, flash drive, or other commonly used 
electronic storage medium and clearly mark the medium as CBI. Mail the 
electronic medium to U.S. Environmental Protection Agency, Office of 
Air Quality Planning and Standards, Sector Policies and Programs 
Division, CORE CBI Office, U.S. EPA Mailroom (C404-02), Attention: 
Group Leader, Measurement Policy Group, 4930 Old Page Rd., Durham, NC 
27703. The same file with the CBI omitted must be submitted to the EPA 
via the EPA's CDX as described in paragraph (f)(1) and (2) of this 
section. All CBI claims must be asserted at the time of submission. 
Furthermore, under CAA section 114(c) emissions data is not entitled to 
confidential treatment, and the EPA is required to make emissions data 
available to the public. Thus, emissions data will not be protected as 
CBI and will be made publicly available.
    (g) CEMS relative accuracy test audit (RATA) Performance evaluation 
reports. Beginning no later than October 13, 2020, you must start 
submitting CEMS RATA performance evaluation reports in accordance with 
this paragraph (g). Unless otherwise specified in this subpart, within 
60 days after the date of completing each continuous monitoring system 
performance evaluation (as defined in Sec.  63.2), you must submit the 
results of the performance evaluation following the procedures 
specified in paragraphs (g)(1) through (3) of this section.
    (1) Performance evaluations of CMS measuring RATA pollutants that 
are supported by the EPA's ERT as listed on the EPA's ERT website at 
the time of the evaluation. Submit the results of the performance 
evaluation to the EPA via CEDRI, which can be accessed through the 
EPA's CDX. The data must be submitted in a file format generated 
through the use of the EPA's ERT. Alternatively, you may submit an 
electronic file consistent with the XML schema listed on the EPA's ERT 
website.
    (2) Performance evaluations of CMS measuring RATA pollutants that 
are not supported by the EPA's ERT as listed on the EPA's ERT website 
at the time of the evaluation. The results of the performance 
evaluation must be included as an attachment in the ERT or an alternate 
electronic file consistent with the XML schema listed on the EPA's ERT 
website. Submit the ERT generated package or alternative file to the 
EPA via CEDRI.
    (3) Confidential business information (CBI). The EPA will make all 
the information submitted through CEDRI available to the public without 
further notice to you. Do not use CEDRI to submit information you claim 
as CBI. Anything submitted using CEDRI cannot later be claimed to be 
CBI. Although we do not expect persons to assert a claim of CBI, if you 
wish to assert a CBI claim, you must submit a complete file, including 
information claimed to be CBI, to the EPA. The file must be generated 
through the use of the EPA's ERT or an alternate electronic file 
consistent with the XML schema listed on the EPA's ERT website. Submit 
the file on a compact disc, flash drive, or other commonly used 
electronic storage medium and clearly mark the medium as CBI. Mail the 
electronic medium to U.S. Environmental Protection Agency, Office of 
Air Quality Planning and Standards, Sector Policies and Programs 
Division, CORE CBI Office, U.S. EPA Mailroom (C404-02), Attention: 
Group Leader, Measurement Policy Group, 4930 Old Page Rd., Durham, NC 
27703. The same file with the CBI omitted must be submitted to the EPA 
via the EPA's CDX as described in paragraphs (g)(1) and (2) of this 
section. All CBI claims must be asserted at the time of submission. 
Furthermore, under CAA section 114(c) emissions data is not entitled to 
confidential treatment, and the EPA is required to make emissions data 
available to the public. Thus, emissions data will not be protected as 
CBI and will be made publicly available.
    (h) Claims of EPA system outage. If you are required to 
electronically submit a report through CEDRI in the EPA's CDX, you may 
assert a claim of EPA system outage for failure to timely comply with 
that reporting requirement. To assert a claim of EPA system outage, you 
must meet the requirements outlined in paragraphs (h)(1) through (7) of 
this section.
    (1) You must have been or will be precluded from accessing CEDRI 
and submitting a required report within the time prescribed due to an 
outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) You must submit notification to the Administrator in writing as 
soon as possible following the date you first

[[Page 49155]]

knew, or through due diligence should have known, that the event may 
cause or has caused a delay in reporting.
    (5) You must provide to the Administrator a written description 
identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met that reporting requirement at the time of the notification, 
the date you reported.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (i) Claims of force majeure. If you are required to electronically 
submit a report through CEDRI in the EPA's CDX, you may assert a claim 
of force majeure for failure to timely comply with that reporting 
requirement. To assert a claim of force majeure, you must meet the 
requirements outlined in paragraphs (i)(1) through (5) of this section.
    (1) You may submit a claim if a force majeure event is about to 
occur, occurs, or has occurred or there are lingering effects from such 
an event within the period of time beginning five business days prior 
to the date the submission is due. For the purposes of this paragraph 
(i)(1), a force majeure event is defined as an event that will be or 
has been caused by circumstances beyond the control of the affected 
facility, its contractors, or any entity controlled by the affected 
facility that prevents you from complying with the requirement to 
submit a report electronically within the time period prescribed. 
Examples of such events are acts of nature (e.g., hurricanes, 
earthquakes, or floods), acts of war or terrorism, or equipment failure 
or safety hazard beyond the control of the affected facility (e.g., 
large scale power outage).
    (2) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (3) You must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.

0
21. Section 63.2525 is amended by revising the introductory text and 
paragraphs (a), (e)(1)(ii), (f), (h), and (j) and adding paragraphs (l) 
through (u) to read as follows:

Sec.  63.2525  What records must I keep?

    You must keep the records specified in paragraphs (a) through (t) 
of this section.
    (a) Except as specified in Sec. Sec.  63.2450(e)(4), 63.2480(f), 
and 63.2485(p) and (q) and paragraph (t) of this section, each 
applicable record required by subpart A of this part and in referenced 
subparts F, G, SS, UU, WW, and GGG of this part and in referenced 
subpart F of 40 CFR part 65.
* * * * *
    (e) * * *
    (1) * * *
    (ii) You control the Group 2 batch process vents using a flare that 
meets the requirements of Sec.  63.987 or Sec.  63.2450(e)(5), as 
applicable.
* * * * *
    (f) A record of each time a safety device is opened to avoid unsafe 
conditions in accordance with Sec.  63.2450(p).
* * * * *
    (h) Except as specified in paragraph (l) of this section, for each 
CEMS, you must keep records of the date and time that each deviation 
started and stopped, and whether the deviation occurred during a period 
of startup, shutdown, or malfunction or during another period.
* * * * *
    (j) In the SSMP required by Sec.  63.6(e)(3) of subpart A, you are 
not required to include Group 2 emission points, unless those emission 
points are used in an emissions average. For equipment leaks, the SSMP 
requirement is limited to control devices and is optional for other 
equipment. On and after August 12, 2023, this paragraph (j) no longer 
applies.
* * * * *
    (l) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), paragraph (h) of this section no longer applies. Instead, 
for each deviation from an emission limit, operating limit, or work 
practice standard, you must keep a record of the information specified 
in paragraph (l)(1) through (3) of this section. The records shall be 
maintained as specified in Sec.  63.10(b)(1) of subpart A.
    (1) In the event that an affected unit does not meet an applicable 
standard, record the number of deviations. For each deviation record 
the date, time, and duration of each deviation.
    (2) For each deviation from an applicable standard, record and 
retain a list of the affected sources or equipment, an estimate of the 
quantity of each regulated pollutant emitted over any emission limit 
and a description of the method used to estimate the emissions.
    (3) Record actions taken to minimize emissions in accordance with 
Sec.  63.2450(u) and any corrective actions taken to return the 
affected unit to its normal or usual manner of operation.
    (m) For each flare subject to the requirements in Sec.  
63.2450(e)(5), you must keep records specified in paragraphs (m)(1) 
through (14) of this section in lieu of the information required in 
Sec.  63.998(a)(1) of subpart SS.
    (1) Retain records of the output of the monitoring device used to 
detect the presence of a pilot flame or flare flame as required in 
Sec.  63.670(b) of subpart CC and the presence of a pilot flame as 
required in Sec.  63.2450(e)(5)(viii)(D) for a minimum of 2 years. 
Retain records of each 15-minute block during which there was at least 
one minute that no pilot flame or flare flame is present when regulated 
material is routed to a flare for a minimum of 5 years. For a pressure-
assisted multi-point flare that uses cross-lighting, retain records of 
each 15-minute block during which there was at least one minute that no 
pilot flame is present on each stage when regulated material is routed 
to a flare for a minimum of 5 years. You may reduce the collected 
minute-by-minute data to a 15-minute block basis with an indication of 
whether there was at least one minute where no pilot flame or flare 
flame was present.
    (2) Retain records of daily visible emissions observations as 
specified in paragraphs (m)(2)(i) through (iv) of this section, as 
applicable, for a minimum of 3 years.
    (i) To determine when visible emissions observations are required, 
the record must identify all periods when regulated material is vented 
to the flare.
    (ii) If visible emissions observations are performed using Method 
22 of 40

[[Page 49156]]

CFR part 60, appendix A-7, then the record must identify whether the 
visible emissions observation was performed, the results of each 
observation, total duration of observed visible emissions, and whether 
it was a 5-minute or 2-hour observation. Record the date and start time 
of each visible emissions observation.
    (iii) If a video surveillance camera is used pursuant to Sec.  
63.670(h)(2) of subpart CC, then the record must include all video 
surveillance images recorded, with time and date stamps.
    (iv) For each 2 hour period for which visible emissions are 
observed for more than 5 minutes in 2 consecutive hours, then the 
record must include the date and start and end time of the 2 hour 
period and an estimate of the cumulative number of minutes in the 2 
hour period for which emissions were visible.
    (3) The 15-minute block average cumulative flows for flare vent gas 
and, if applicable, total steam, perimeter assist air, and premix 
assist air specified to be monitored under Sec.  63.670(i) of subpart 
CC, along with the date and time interval for the 15-minute block. If 
multiple monitoring locations are used to determine cumulative vent gas 
flow, total steam, perimeter assist air, and premix assist air, then 
retain records of the 15-minute block average flows for each monitoring 
location for a minimum of 2 years, and retain the 15-minute block 
average cumulative flows that are used in subsequent calculations for a 
minimum of 5 years. If pressure and temperature monitoring is used, 
then retain records of the 15-minute block average temperature, 
pressure, and molecular weight of the flare vent gas or assist gas 
stream for each measurement location used to determine the 15-minute 
block average cumulative flows for a minimum of 2 years, and retain the 
15-minute block average cumulative flows that are used in subsequent 
calculations for a minimum of 5 years.
    (4) The flare vent gas compositions specified to be monitored under 
Sec.  63.670(j) of subpart CC. Retain records of individual component 
concentrations from each compositional analysis for a minimum of 2 
years. If an NHVvg analyzer is used, retain records of the 15-minute 
block average values for a minimum of 5 years.
    (5) Each 15-minute block average operating parameter calculated 
following the methods specified in Sec.  63.670(k) through (n) of 
subpart CC, as applicable.
    (6) All periods during which operating values are outside of the 
applicable operating limits specified in Sec. Sec.  63.670(d) through 
(f) of subpart CC and 63.2450(e)(5)(viii) when regulated material is 
being routed to the flare.
    (7) All periods during which you do not perform flare monitoring 
according to the procedures in Sec.  63.670(g) through (j) of subpart 
CC.
    (8) For pressure-assisted multi-point flares, if a stage of burners 
on the flare uses cross-lighting, then a record of any changes made to 
the distance between burners.
    (9) For pressure-assisted multi-point flares, all periods when the 
pressure monitor(s) on the main flare header show burners are operating 
outside the range of the manufacturer's specifications. Indicate the 
date and time for each period, the pressure measurement, the stage(s) 
and number of burners affected, and the range of manufacturer's 
specifications.
    (10) For pressure-assisted multi-point flares, all periods when the 
staging valve position indicator monitoring system indicates a stage of 
the pressure-assisted multi-point flare should not be in operation and 
when a stage of the pressure-assisted multi-point flare should be in 
operation and is not. Indicate the date and time for each period, 
whether the stage was supposed to be open, but was closed or vice 
versa, and the stage(s) and number of burners affected.
    (11) Records of periods when there is flow of vent gas to the 
flare, but when there is no flow of regulated material to the flare, 
including the start and stop time and dates of periods of no regulated 
material flow.
    (12) Records when the flow of vent gas exceeds the smokeless 
capacity of the flare, including start and stop time and dates of the 
flaring event.
    (13) Records of the root cause analysis and corrective action 
analysis conducted as required in Sec. Sec.  63.670(o)(3) of subpart CC 
and 63.2450(e)(5)(v), including an identification of the affected 
flare, the date and duration of the event, a statement noting whether 
the event resulted from the same root cause(s) identified in a previous 
analysis and either a description of the recommended corrective 
action(s) or an explanation of why corrective action is not necessary 
under Sec.  63.670(o)(5)(i) of subpart CC.
    (14) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.670(o)(5) of subpart CC, a 
description of the corrective action(s) completed within the first 45 
days following the discharge and, for action(s) not already completed, 
a schedule for implementation, including proposed commencement and 
completion dates.
    (n) For each flow event from a bypass line subject to the 
requirements in Sec.  63.2450(e)(6), you must maintain records 
sufficient to determine whether or not the detected flow included flow 
requiring control. For each flow event from a bypass line requiring 
control that is released either directly to the atmosphere or to a 
control device not meeting the requirements specified in Tables 1 
through 7 to this subpart, you must include an estimate of the volume 
of gas, the concentration of organic HAP in the gas and the resulting 
emissions of organic HAP that bypassed the control device using process 
knowledge and engineering estimates.
    (o) For each nonregenerative adsorber and regenerative adsorber 
that is regenerated offsite subject to the requirements in Sec.  
63.2450(e)(7), you must keep the applicable records specified in 
paragraphs (o)(1) through (4) of this section.
    (1) Outlet HAP or TOC concentration for each adsorber bed measured 
during each performance test conducted.
    (2) Daily outlet HAP or TOC concentration.
    (3) Date and time you last replaced the adsorbent.
    (4) If you conduct monitoring less frequently than daily as 
specified in Sec.  63.2450(e)(7)(iii)(B), you must record the average 
life of the bed.
    (p) For each maintenance vent opening subject to the requirements 
in Sec.  63.2450(v), you must keep the applicable records specified in 
paragraphs (p)(1) through (5) of this section.
    (1) You must maintain standard site procedures used to deinventory 
equipment for safety purposes (e.g., hot work or vessel entry 
procedures) to document the procedures used to meet the requirements in 
Sec.  63.2450(v). The current copy of the procedures must be retained 
and available on-site at all times. Previous versions of the standard 
site procedures, as applicable, must be retained for five years.
    (2) If complying with the requirements of Sec.  63.2450(v)(1)(i) 
and the lower explosive limit at the time of the vessel opening exceeds 
10 percent, identification of the maintenance vent, the process units 
or equipment associated with the maintenance vent, the date of 
maintenance vent opening, and the lower explosive limit at the time of 
the vessel opening.
    (3) If complying with the requirements of Sec.  63.2450(v)(1)(ii) 
and either the vessel pressure at the time of the vessel opening 
exceeds 5 psig or the lower explosive limit at the time of the active 
purging was initiated exceeds 10 percent, identification of the

[[Page 49157]]

maintenance vent, the process units or equipment associated with the 
maintenance vent, the date of maintenance vent opening, the pressure of 
the vessel or equipment at the time of discharge to the atmosphere and, 
if applicable, the lower explosive limit of the vapors in the equipment 
when active purging was initiated.
    (4) If complying with the requirements of Sec.  63.2450(v)(1)(iii), 
records of the estimating procedures used to determine the total 
quantity of VOC in the equipment and the type and size limits of 
equipment that contain less than 50 pounds of VOC at the time of 
maintenance vent opening. For each maintenance vent opening that 
contains greater than 50 pounds of VOC for which the deinventory 
procedures specified in paragraph (p)(1) of this section are not 
followed or for which the equipment opened exceeds the type and size 
limits established in the records specified in this paragraph (p)(4), 
records that identify the maintenance vent, the process units or 
equipment associated with the maintenance vent, the date of maintenance 
vent opening, and records used to estimate the total quantity of VOC in 
the equipment at the time the maintenance vent was opened to the 
atmosphere.
    (5) If complying with the requirements of Sec.  63.2450(v)(1)(iv), 
identification of the maintenance vent, the process units or equipment 
associated with the maintenance vent, records documenting actions taken 
to comply with other applicable alternatives and why utilization of 
this alternative was required, the date of maintenance vent opening, 
the equipment pressure and lower explosive limit of the vapors in the 
equipment at the time of discharge, an indication of whether active 
purging was performed and the pressure of the equipment during the 
installation or removal of the blind if active purging was used, the 
duration the maintenance vent was open during the blind installation or 
removal process, and records used to estimate the total quantity of VOC 
in the equipment at the time the maintenance vent was opened to the 
atmosphere for each applicable maintenance vent opening.
    (q) For each pressure relief device subject to the pressure release 
management work practice standards in Sec.  63.2480(e), you must keep 
the records specified in paragraphs (q)(1) through (3) of this section.
    (1) Records of the prevention measures implemented as required in 
Sec.  63.2480(e)(3)(ii).
    (2) Records of the number of releases during each calendar year and 
the number of those releases for which the root cause was determined to 
be a force majeure event. Keep these records for the current calendar 
year and the past 5 calendar years.
    (3) For each release to the atmosphere, you must keep the records 
specified in paragraphs (q)(3)(i) through (iv) of this section.
    (i) The start and end time and date of each pressure release to the 
atmosphere.
    (ii) Records of any data, assumptions, and calculations used to 
estimate of the mass quantity of each organic HAP released during the 
event.
    (iii) Records of the root cause analysis and corrective action 
analysis conducted as required in Sec.  63.2480(e)(3)(iii), including 
an identification of the affected facility, a statement noting whether 
the event resulted from the same root cause(s) identified in a previous 
analysis and either a description of the recommended corrective 
action(s) or an explanation of why corrective action is not necessary 
under Sec.  63.2480(e)(7)(i).
    (iv) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.2480(e)(7), a description 
of the corrective action(s) completed within the first 45 days 
following the discharge and, for action(s) not already completed, a 
schedule for implementation, including proposed commencement and 
completion dates.
    (r) For each heat exchange system, beginning no later than the 
compliance dates specified in Sec.  63.2445(g), the recordkeeping 
requirements of Sec.  63.104(f)(1) no longer apply; instead, you must 
keep records in paragraphs (r)(1) through (4) of this section.
    (1) Monitoring data required by Sec.  63.2490(d) that indicate a 
leak, the date the leak was detected, or, if applicable, the basis for 
determining there is no leak.
    (2) The dates of efforts to repair leaks.
    (3) The method or procedures used to confirm repair of a leak and 
the date the repair was confirmed.
    (4) Documentation of delay of repair as specified in paragraphs 
(r)(4)(i) through (iv) of this section.
    (i) The reason(s) for delaying repair.
    (ii) A schedule for completing the repair as soon as practical.
    (iii) The date and concentration or mass emissions rate of the leak 
as first identified and the results of all subsequent monitoring events 
during the delay of repair.
    (iv) An estimate of the potential total hydrocarbon emissions from 
the leaking heat exchange system or heat exchanger for each required 
delay of repair monitoring interval following the procedures in 
paragraphs (r)(4)(iv)(A) through (C) of this section.
    (A) If you comply with the total strippable hydrocarbon 
concentration leak action level, as specified in Sec.  
63.2490(d)(1)(iv), you must calculate the mass emissions rate by 
complying with the requirements of Sec.  63.2490(d)(1)(iii)(B) or by 
determining the mass flow rate of the cooling water at the monitoring 
location where the leak was detected. If the monitoring location is an 
individual cooling tower riser, determine the total cooling water mass 
flow rate to the cooling tower. Cooling water mass flow rates may be 
determined using direct measurement, pump curves, heat balance 
calculations, or other engineering methods. If you determine the mass 
flow rate of the cooling water, calculate the mass emissions rate by 
converting the stripping gas leak concentration (in ppmv as methane) to 
an equivalent liquid concentration, in parts per million by weight 
(ppmw), using equation 7-1 from ``Air Stripping Method (Modified El 
Paso Method) for Determination of Volatile Organic Compound Emissions 
from Water Sources'' (incorporated by reference--see Sec.  63.14) and 
multiply the equivalent liquid concentration by the mass flow rate of 
the cooling water.
    (B) For delay of repair monitoring intervals prior to repair of the 
leak, calculate the potential total hydrocarbon emissions for the 
leaking heat exchange system or heat exchanger for the monitoring 
interval by multiplying the mass emissions rate, determined in Sec.  
63.2490(d)(1)(iii)(B) or paragraph (r)(4)(iv)(A) of this section, by 
the duration of the delay of repair monitoring interval. The duration 
of the delay of repair monitoring interval is the time period starting 
at midnight on the day of the previous monitoring event or at midnight 
on the day the repair would have had to be completed if the repair had 
not been delayed, whichever is later, and ending at midnight of the day 
the of the current monitoring event.
    (C) For delay of repair monitoring intervals ending with a repaired 
leak, calculate the potential total hydrocarbon emissions for the 
leaking heat exchange system or heat exchanger for the final delay of 
repair monitoring interval by multiplying the duration of the final 
delay of repair monitoring interval by the mass emissions rate 
determined for the last monitoring event prior to the re-monitoring 
event used to verify the leak was repaired. The duration of the final 
delay of repair monitoring interval is the time period starting at 
midnight of the

[[Page 49158]]

day of the last monitoring event prior to re-monitoring to verify the 
leak was repaired and ending at the time of the re-monitoring event 
that verified that the leak was repaired.
    (s) For process vents and storage tanks in ethylene oxide service 
subject to the requirements of Sec.  63.2493, you must keep the records 
specified in paragraphs (s)(1) through (5) of this section in addition 
to those records specified in paragraph (a) of this section. Records 
for equipment in ethylene oxide service subject to the requirements of 
Sec.  63.2493 are specified in paragraph (a) of this section.
    (1) For process vents, include all uncontrolled, undiluted ethylene 
oxide concentration measurements, and the calculations you used to 
determine the total uncontrolled ethylene oxide mass emission rate for 
the sum of all vent gas streams.
    (2) For storage tanks, records of the concentration of ethylene 
oxide of the fluid stored in each storage tank.
    (3) For equipment, records of the percent ethylene oxide content of 
the process fluid and the method used to determine it.
    (4) If you vent emissions through a closed-vent system to a non-
flare control device, then you must keep records of all periods during 
which operating values are outside of the applicable operating limits 
specified in Sec.  63.2493(b)(4) through (6) when regulated material is 
being routed to the non-flare control device. The record must specify 
the operating parameter, the applicable limit, and the highest (for 
maximum operating limits) or lowest (for minimum operating limits) 
value recorded during the period.
    (5) For pressure vessels subject to Sec.  63.2493(c), records as 
specified in paragraphs (s)(5)(i) through (iv) of this section.
    (i) The date of each performance test conducted according to Sec.  
63.2493(c)(2).
    (ii) The instrument reading of each performance test conducted 
according to Sec.  63.2493(c)(2), including the following:
    (A) Date each defect was detected.
    (B) Date of the next performance test that shows the instrument 
reading is less than 500 ppmv.
    (C) Start and end dates of each period after the date in paragraph 
(s)(5)(ii)(A) of this section when the pressure vessel was completely 
empty.
    (D) Estimated emissions from each defect.
    (t) Any records required to be maintained by this part that are 
submitted electronically via the EPA's CEDRI may be maintained in 
electronic format. This ability to maintain electronic copies does not 
affect the requirement for facilities to make records, data, and 
reports available upon request to a delegated air agency or the EPA as 
part of an on-site compliance evaluation.
    (u) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), the referenced provisions specified in paragraphs (u)(1) 
through (8) of this section do not apply when demonstrating compliance 
with paragraph (a) of this section.
    (1) Section 63.103(c)(2)(i) of subpart F.
    (2) Section 63.103(c)(2)(ii) of subpart F.
    (3) The phrase ``start-up, shutdown and malfunction and'' from 
Sec.  63.103(c)(3) of subpart F.
    (4) The phrase ``other than startups, shutdowns, or malfunctions 
(e.g., a temperature reading of -200 [deg]C on a boiler),'' from Sec.  
63.152(g)(1)(i) of subpart G.
    (5) The phrase ``other than a startup, shutdown, or malfunction'' 
from Sec.  63.152(g)(1)(ii)(C) of subpart G.
    (6) The phrase ``other than startups, shutdowns, or malfunctions'' 
from Sec.  63.152(g)(1)(iii) of subpart G.
    (7) The phrase ``other than a startup, shutdown, or malfunction'' 
from Sec.  63.152(g)(2)(iii) of subpart G.
    (8) Section 63.152(g)(2)(iv)(A) of subpart G.

0
22. Section 63.2535 is amended by revising the introductory text and 
paragraphs (d) and (k) and adding paragraph (m) to read as follows:

Sec.  63.2535  What compliance options do I have if part of my plant is 
subject to both this subpart and another subpart?

    For any equipment, emission stream, or wastewater stream not 
subject to Sec.  63.2493 but subject to other provisions of both this 
subpart and another subpart, you may elect to comply only with the 
provisions as specified in paragraphs (a) through (l) of this section. 
You also must identify the subject equipment, emission stream, or 
wastewater stream, and the provisions with which you will comply, in 
your notification of compliance status report required by Sec.  
63.2520(d).
* * * * *
    (d) Compliance with subpart I, GGG, or MMM of this part. After the 
compliance dates specified in Sec.  63.2445, if you have an affected 
source with equipment subject to subpart I, GGG, or MMM of this part, 
you may elect to comply with the provisions of subpart H, GGG, or MMM 
of this part, respectively, for all such equipment, except the 
affirmative defense requirements in subparts GGG and MMM no longer 
apply.
* * * * *
    (k) Compliance with 40 CFR part 60, subpart VV or VVa, and 40 CFR 
part 61, subpart V. Except as specified in paragraphs (k)(1) and (2) of 
this section, after the compliance date specified in Sec.  63.2445, if 
you have an affected source with equipment that is also subject to the 
requirements of 40 CFR part 60, subpart VV or VVa, or 40 CFR part 61, 
subpart V, you may elect to apply this subpart to all such equipment. 
After the compliance date specified in Sec.  63.2445, if you have an 
affected source with equipment to which this subpart does not apply, 
but which is subject to the requirements of 40 CFR part 60, subpart VV 
or VVa, or 40 CFR part 61, subpart V, you may elect to apply this 
subpart to all such equipment. If you elect either of the methods of 
compliance in this paragraph (k), you must consider all total organic 
compounds, minus methane and ethane, in such equipment for purposes of 
compliance with this subpart, as if they were organic HAP. Compliance 
with the provisions of this subpart, in the manner described in this 
paragraph (k), will constitute compliance with 40 CFR part 60, subpart 
VV or VVa, and 40 CFR part 61, subpart V, as applicable.
    (1) The provision in Sec.  63.2480(b)(4) does not apply to 
connectors in gas/vapor and light liquid service that are subject to 
monitoring under 40 CFR 60.482-11a if complying with the compliance 
option in this paragraph (k).
    (2) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), equipment that must be controlled according to this subpart 
and subpart VVa of 40 CFR part 60 is required only to comply with the 
equipment leak requirements of this subpart, except you must also 
comply with the calibration drift assessment requirements specified at 
40 CFR 60.485a(b)(2) if they are required to do so in subpart VVa of 40 
CFR part 60. When complying with the calibration drift assessment 
requirements at 40 CFR 60.485a(b)(2), the requirement at 40 CFR 
60.486a(e)(8)(v) to record the instrument reading for each scale used 
applies.
* * * * *
    (m) Overlap of this subpart with other regulations for flares. (1) 
Beginning no later than the compliance dates specified in Sec.  
63.2445(g), flares that control ethylene oxide emissions from affected 
sources in ethylene oxide service as defined in Sec.  63.2550 or are 
used to control emissions from MCPUs that produce olefins and 
polyolefins, subject to the provisions of 40 CFR

[[Page 49159]]

60.18 or 63.11, and used as a control device for an emission point 
subject to the emission limits and work practice standards in Tables 1, 
2, 4 or 5 to this subpart are required to comply only with the 
provisions specified in Sec.  63.2450(e)(5). At any time before the 
compliance dates specified in Sec.  63.2445(g), flares that are subject 
to the provisions of 40 CFR 60.18 or 63.11 and elect to comply with the 
requirements in Sec.  63.2450(e)(5) are required to comply only with 
the provisions specified in this subpart. For purposes of compliance 
with this paragraph (m), ``MCPUs that produces olefins or polyolefins'' 
includes only those MCPUs that manufacture ethylene, propylene, 
polyethylene, and/or polypropylene as a product. By-products and 
impurities as defined in Sec.  63.101, as well as wastes and trace 
contaminants, are not considered products.
    (2) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), flares subject to Sec.  63.987 and used as a control device 
for an emission point subject to the emission limits and work practice 
standards in Tables 1, 2, 4 or 5 to this subpart are only required to 
comply with Sec.  63.2450(e)(5).
    (3) Beginning no later than the compliance dates specified in Sec.  
63.2445(g), flares subject to the requirements in subpart CC of this 
part and used as a control device for an emission point subject to the 
emission limits and work practice standards in Tables 1, 2, 4 or 5 to 
this subpart are only required to comply with the flare requirements in 
subpart CC of this part. This paragraph (m)(3) does not apply to multi-
point pressure assisted flares.

0
23. Section 63.2545 is amended by revising paragraph (b) introductory 
text and adding paragraph (b)(5) to read as follows:

Sec.  63.2545  Who implements and enforces this subpart?

* * * * *
    (b) In delegating implementation and enforcement authority of this 
subpart to a state, local, or tribal agency under subpart E of this 
part, the authorities contained in paragraphs (b)(1) through (5) of 
this section are retained by the Administrator of U.S. EPA and are not 
delegated to the state, local, or tribal agency.
* * * * *
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

0
24. Section 63.2550 is amended in paragraph (i) by:
0
a. Revising paragraphs (4) and (8) in the definition of ``Batch process 
vent'';
0
b. Adding, in alphabetical order, definitions for ``Bench-scale 
process'' and ``Breakthrough'';
0
c. Adding paragraphs (8), (9), (10), and (11) in the definition of 
``Continuous process vent'';
0
d. Revising paragraph (3) in the definition of ``Deviation'';
0
e. Adding, in alphabetical order, definitions for ``Force majeure,'' 
``Heat exchange system,'' ``In ethylene oxide service,'' and ``Loading 
rack'';
0
f. Revising paragraph (6) in the definition of ``Miscellaneous organic 
chemical manufacturing process''; and
0
g. Adding, in alphabetical order, definitions for ``Pressure release,'' 
``Pressure relief device,'' ``Pressure vessel,'' ``Relief valve,'' and 
``Thermal expansion relief valve.''
    The revisions and additions read as follows:

Sec.  63.2550  What definitions apply to this subpart?

* * * * *
    (i) * * *
    Batch process vent * * *
    (4) Gaseous streams routed to a fuel gas system(s) unless on and 
after August 12, 2023, the fuel gas system(s) supplies a flare of which 
50 percent or more of the fuel gas burned in the flare is derived from 
an MCPU that has processes and/or equipment in ethylene oxide service, 
or produces olefins or polyolefins;
* * * * *
    (8) Except for batch process vents in ethylene oxide service, 
emission streams from emission episodes that are undiluted and 
uncontrolled containing less than 50 ppmv HAP are not part of any batch 
process vent. A vent from a unit operation, or a vent from multiple 
unit operations that are manifolded together, from which total 
uncontrolled HAP emissions are less than 200 lb/yr is not a batch 
process vent; emissions for all emission episodes associated with the 
unit operation(s) must be included in the determination of the total 
mass emitted. The HAP concentration or mass emission rate may be 
determined using any of the following: Process knowledge that no HAP 
are present in the emission stream; an engineering assessment as 
discussed in Sec.  63.1257(d)(2)(ii), except that you do not need to 
demonstrate that the equations in Sec.  63.1257(d)(2)(i) do not apply, 
and the precompliance reporting requirements specified in Sec.  
63.1257(d)(2)(ii)(E) do not apply for the purposes of this 
demonstration; equations specified in Sec.  63.1257(d)(2)(i), as 
applicable; test data using Method 18 of 40 CFR part 60, appendix A; or 
any other test method that has been validated according to the 
procedures in EPA Method 301 of appendix A to this part.
    Bench-scale process means a process (other than a research and 
development facility) that is operated on a small scale, such as one 
capable of being located on a laboratory bench top. This bench-scale 
equipment will typically include reagent feed vessels, a small reactor 
and associated product separator, recovery and holding equipment. These 
processes are only capable of producing small quantities of product.
* * * * *
    Breakthrough means the time when the level of HAP or TOC, measured 
at the outlet of the first bed, has been detected is at the highest 
concentration allowed to be discharged from the adsorber system and 
indicates that the adsorber bed should be replaced.
* * * * *
    Continuous process vent * * *
    (8) On and after August 12, 2023, Sec.  63.107(h)(3) applies unless 
the fuel gas system supplies a flare of which 50 percent or more of the 
fuel gas burned in the flare is derived from an MCPU that has processes 
and/or equipment in ethylene oxide service, or produces olefins or 
polyolefins.
    (9) On and after August 12, 2023, Sec.  63.107(h)(9) no longer 
applies.
    (10) On and after August 12, 2023, Sec.  63.107(i) no longer 
applies. Instead, a process vent is the point of discharge to the 
atmosphere (or the point of entry into a control device, if any) of a 
gas stream if the gas stream meets the criteria specified in this 
paragraph. The gas stream would meet the characteristics specified in 
Sec.  63.107(b) through (g) of subpart F, but, for purposes of avoiding 
applicability, has been deliberately interrupted, temporarily 
liquefied, routed through any item of equipment for no process purpose, 
or disposed of in a flare that does not meet the criteria in Sec.  
63.11(b) of subpart A or Sec.  63.2450(e)(5) as applicable, or an 
incinerator that does not reduce emissions of organic HAP by 98 percent 
or to a concentration of 20 parts per million by volume, whichever is 
less stringent.
    (11) Section 63.107(d) does not apply to continuous process vents 
in ethylene oxide service.
* * * * *
    Deviation * * *
    (3) Before August 12, 2023, fails to meet any emission limit, 
operating limit, or work practice standard in this subpart during 
startup, shutdown, or

[[Page 49160]]

malfunction, regardless of whether or not such failure is permitted by 
this subpart. On and after August 12, 2023, this paragraph (3) no 
longer applies.
* * * * *
    Force majeure event means a release of HAP, either directly to the 
atmosphere from a pressure relief device or discharged via a flare, 
that is demonstrated to the satisfaction of the Administrator to result 
from an event beyond the owner or operator's control, such as natural 
disasters; acts of war or terrorism; loss of a utility external to the 
MCPU (e.g., external power curtailment), excluding power curtailment 
due to an interruptible service agreement; and fire or explosion 
originating at a near or adjoining facility outside of the 
miscellaneous organic chemical manufacturing process unit that impacts 
the miscellaneous organic chemical manufacturing process unit's ability 
to operate.
* * * * *
    Heat exchange system means a device or collection of devices used 
to transfer heat from process fluids to water without intentional 
direct contact of the process fluid with the water (i.e., non-contact 
heat exchanger) and to transport and/or cool the water in a closed-loop 
recirculation system (cooling tower system) or a once-through system 
(e.g., river or pond water). For closed-loop recirculation systems, the 
heat exchange system consists of a cooling tower, all miscellaneous 
organic chemical manufacturing process unit heat exchangers that are in 
organic HAP service, as defined in this subpart, serviced by that 
cooling tower, and all water lines to and from these miscellaneous 
organic chemical manufacturing process unit heat exchangers. For once-
through systems, the heat exchange system consists of all heat 
exchangers that are in organic HAP service, as defined in this subpart, 
servicing an individual miscellaneous organic chemical manufacturing 
process unit and all water lines to and from these heat exchangers. 
Sample coolers or pump seal coolers are not considered heat exchangers 
for the purpose of this definition and are not part of the heat 
exchange system. Intentional direct contact with process fluids results 
in the formation of a wastewater.
* * * * *
    In ethylene oxide service means the following:
    (1) For equipment leaks, any equipment that contains or contacts a 
fluid (liquid or gas) that is at least 0.1 percent by weight of 
ethylene oxide. If information exists that suggests ethylene oxide 
could be present in equipment, the equipment is considered to be ``in 
ethylene oxide service'' unless sampling and analysis is performed as 
specified in Sec.  63.2492 to demonstrate that the equipment does not 
meet the definition of being ``in ethylene oxide service''. Examples of 
information that could suggest ethylene oxide could be present in 
equipment, include calculations based on safety data sheets, material 
balances, process stoichiometry, or previous test results provided the 
results are still relevant to the current operating conditions.
    (2) For process vents, 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). If 
information exists that suggests ethylene oxide could be present in a 
batch or continuous process vent, then the batch or continuous process 
vent is considered to be ``in ethylene oxide service'' unless an 
analysis is performed as specified in Sec.  63.2492 to demonstrate that 
the batch or continuous process vent does not meet the definition of 
being ``in ethylene oxide service''. Examples of information that could 
suggest ethylene oxide could be present in a batch or continuous 
process vent, include calculations based on safety data sheets, 
material balances, process stoichiometry, or previous test results 
provided the results are still relevant to the current operating 
conditions.
    (3) For storage tanks, storage tanks of any capacity and vapor 
pressure storing a liquid that is at least 0.1 percent by weight of 
ethylene oxide. If knowledge exists that suggests ethylene oxide could 
be present in a storage tank, then the storage tank is considered to be 
``in ethylene oxide service'' unless sampling and analysis is performed 
as specified in Sec.  63.2492 to demonstrate that the storage tank does 
not meet the definition of being ``in ethylene oxide service''. 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'' in this section do not apply for 
storage tanks that may be in ethylene oxide service. Examples of 
information that could suggest ethylene oxide could be present in a 
storage tank, include calculations based on safety data sheets, 
material balances, process stoichiometry, or previous test results 
provided the results are still relevant to the current operating 
conditions.
* * * * *
    Loading rack means a single system used to fill tank trucks and 
railcars at a single geographic site. Loading equipment and operations 
that are physically separate (i.e., do not share common piping, valves, 
and other equipment) are considered to be separate loading racks.
* * * * *
    Miscellaneous organic chemical manufacturing process * * *
    (6) The end of a process that produces a solid material is either 
up to and including the dryer or extruder, or for a polymer production 
process without a dryer or extruder, it is up to and including the die 
plate or solid-state reactor, except in two cases. If the dryer, 
extruder, die plate, or solid-state reactor is followed by an operation 
that is designed and operated to remove HAP solvent or residual HAP 
monomer from the solid, then the solvent removal operation is the last 
step in the process. If the dried solid is diluted or mixed with a HAP-
based solvent, then the solvent removal operation is the last step in 
the process.
* * * * *
    Pressure release means the emission of materials resulting from the 
system pressure being greater than the set pressure of the pressure 
relief device. This release can be one release or a series of releases 
over a short time period.
    Pressure relief device means a valve, rupture disk, or similar 
device used only to release an unplanned, nonroutine discharge of gas 
from process equipment in order to avoid safety hazards or equipment 
damage. A pressure relief device discharge can result from an operator 
error, a malfunction such as a power failure or equipment failure, or 
other unexpected cause. Such devices include conventional, spring-
actuated relief valves, balanced bellows relief valves, pilot-operated 
relief valves, rupture disks, and breaking, buckling, or shearing pin 
devices. Devices that are actuated either by a pressure of less than or 
equal to 2.5 pounds per square inch gauge or by a vacuum are not 
pressure relief devices.
    Pressure vessel means a storage vessel that is used to store 
liquids or gases and is designed not to vent to the atmosphere as a 
result of compression of the vapor headspace in the pressure vessel 
during filling of the pressure vessel to its design capacity.
* * * * *

[[Page 49161]]

    Relief valve means a type of pressure relief device that is 
designed to re-close after the pressure relief.
* * * * *
    Thermal expansion relief valve means a pressure relief valve 
designed to protect equipment from excess pressure due to thermal 
expansion of blocked liquid-filled equipment or piping due to ambient 
heating or heat from a heat tracing system. Pressure relief valves 
designed to protect equipment from excess pressure due to blockage 
against a pump or compressor or due to fire contingency are not thermal 
expansion relief valves.
* * * * *

0
25. Table 1 to subpart FFFF of part 63 is revised to read as follows:
    As required in Sec.  63.2455, you must meet each emission limit and 
work practice standard in the following table that applies to your 
continuous process vents:

  Table 1 to Subpart FFFF of Part 63--Emission Limits and Work Practice Standards for Continuous Process Vents
----------------------------------------------------------------------------------------------------------------
           For each . . .                  For which . . .                      Then you must . . .
----------------------------------------------------------------------------------------------------------------
1. Group 1 continuous process vent.  a. Not applicable..........  i. Reduce emissions of total organic HAP by
                                                                   >=98 percent by weight or to an outlet
                                                                   process concentration <=20 ppmv as organic
                                                                   HAP or TOC by venting emissions through a
                                                                   closed-vent system to any combination of
                                                                   control devices (except a flare); or
                                                                  ii. Reduce emissions of total organic HAP by
                                                                   venting emissions through a closed vent
                                                                   system to a flare; or
                                                                  iii. Use a recovery device to maintain the TRE
                                                                   above 1.9 for an existing source or above 5.0
                                                                   for a new source.
2. Halogenated Group 1 continuous    a. You use a combustion      i. Use a halogen reduction device after the
 process vent stream.                 control device to control    combustion device to reduce emissions of
                                      organic HAP emissions.       hydrogen halide and halogen HAP by >=99
                                                                   percent by weight, or to <=0.45 kg/hr, or to
                                                                   <=20 ppmv; or
                                                                  ii. Use a halogen reduction device before the
                                                                   combustion device to reduce the halogen atom
                                                                   mass emission rate to <=0.45 kg/hr or to a
                                                                   concentration <=20 ppmv.
3. Group 2 continuous process vent   You use a recovery device    Comply with the requirements in Sec.
 at an existing source.               to maintain the TRE level    63.2450(e)(4) and the requirements in Sec.
                                      >1.9 but <=5.0.              63.993 and the requirements referenced
                                                                   therein.
4. Group 2 continuous process vent   You use a recovery device    Comply with the requirements in Sec.
 at a new source.                     to maintain the TRE level    63.2450(e)(4) and the requirements in Sec.
                                      >5.0 but <=8.0.              63.993 and the requirements referenced
                                                                   therein.
5. Continuous process vent.........  Beginning no later than the  Comply with the applicable emission limits
                                      compliance dates specified   specified in items 1 through 4 of this Table,
                                      in Sec.   63.2445(i), the    and also:
                                      continuous process vent     i. Reduce emissions of ethylene oxide by
                                      contains ethylene oxide      venting emissions through a closed-vent
                                      such that it is considered   system to a flare; or
                                      to be in ethylene oxide     ii. Reduce emissions of ethylene oxide by
                                      service as defined in Sec.   venting emissions through a closed-vent
                                        63.2550.                   system to a control device that reduces
                                                                   ethylene oxide by >=99.9 percent by weight,
                                                                   or to a concentration <1 ppmv for each
                                                                   process vent or to <5 pounds per year for all
                                                                   combined process vents.
----------------------------------------------------------------------------------------------------------------

0
26. Table 2 to subpart FFFF of part 63 is revised to read as follows:
    As required in Sec.  63.2460, you must meet each emission limit and 
work practice standard in the following table that applies to your 
batch process vents:

     Table 2 to Subpart FFFF of Part 63--Emission Limits and Work Practice Standards for Batch Process Vents
----------------------------------------------------------------------------------------------------------------
       For each . . .                    Then you must . . .                       And you must . . .
----------------------------------------------------------------------------------------------------------------
1. Process with Group 1       a. Reduce collective uncontrolled         Not applicable.
 batch process vents.          organic HAP emissions from the sum of
                               all batch process vents within the
                               process by >=98 percent by weight by
                               venting emissions from a sufficient
                               number of the vents through one or more
                               closed-vent systems to any combination
                               of control devices (except a flare); or
                              b. Reduce collective uncontrolled         Not applicable.
                               organic HAP emissions from the sum of
                               all batch process vents within the
                               process by >=95 percent by weight by
                               venting emissions from a sufficient
                               number of the vents through one or more
                               closed-vent systems to any combination
                               of recovery devices or a biofilter,
                               except you may elect to comply with the
                               requirements of subpart WW of this part
                               for any process tank; or

[[Page 49162]]

 
                              c. Reduce uncontrolled organic HAP        For all other batch process vents within
                               emissions from one or more batch          the process, reduce collective organic
                               process vents within the process by       HAP emissions as specified in item 1.a
                               venting through a closed-vent system to   and/or item 1.b of this Table.
                               a flare or by venting through one or
                               more closed-vent systems to any
                               combination of control devices
                               (excluding a flare) that reduce organic
                               HAP to an outlet concentration <=20
                               ppmv as TOC or total organic HAP.
2. Halogenated Group 1 batch  a. Use a halogen reduction device after   i. Reduce overall emissions of hydrogen
 process vent for which you    the combustion control device; or         halide and halogen HAP by >=99 percent;
 use a combustion device to                                              or
 control organic HAP                                                    ii. Reduce overall emissions of hydrogen
 emissions.                                                              halide and halogen HAP to <=0.45 kg/hr;
                                                                         or
                                                                        iii. Reduce overall emissions of
                                                                         hydrogen halide and halogen HAP to a
                                                                         concentration <=20 ppmv.
                              b. Use a halogen reduction device before  Reduce the halogen atom mass emission
                               the combustion control device.            rate to <=0.45 kg/hr or to a
                                                                         concentration <=20 ppmv.
3. Batch process vent that    Beginning no later than the compliance    Not applicable.
 contains ethylene oxide       dates specified in Sec.   63.2445(i),
 such that it is considered    comply with the applicable emission
 to be in ethylene oxide       limits specified in items 1 and 2 of
 service as defined in Sec.    this Table, and also:
  63.2550.                    i. Reduce emissions of ethylene oxide by
                               venting emissions through a closed-vent
                               system to a flare; or.
                              ii. Reduce emissions of ethylene oxide
                               by venting emissions through a closed-
                               vent system to a control device that
                               reduces ethylene oxide by >=99.9
                               percent by weight, or to a
                               concentration <1 ppmv for each process
                               vent or to <5 pounds per year for all
                               combined process vents..
----------------------------------------------------------------------------------------------------------------

0
27. Table 4 to subpart FFFF of part 63 is revised to read as follows:
    As required in Sec.  63.2470, you must meet each emission limit in 
the following table that applies to your storage tanks:

                      Table 4 to Subpart FFFF of Part 63--Emission Limits for Storage Tanks
----------------------------------------------------------------------------------------------------------------
           For each . . .                  For which . . .                      Then you must . . .
----------------------------------------------------------------------------------------------------------------
1. Group 1 storage tank............  a. The maximum true vapor    i. Reduce total HAP emissions by >=95 percent
                                      pressure of total HAP at     by weight or to <=20 ppmv of TOC or organic
                                      the storage temperature is   HAP and <=20 ppmv of hydrogen halide and
                                      >=76.6 kilopascals.          halogen HAP by venting emissions through a
                                                                   closed vent system to any combination of
                                                                   control devices (excluding a flare); or
                                                                  ii. Reduce total organic HAP emissions by
                                                                   venting emissions through a closed vent
                                                                   system to a flare; or
                                                                  iii. Comply with the requirements in Sec.
                                                                   63.2450(e)(4), as applicable; and reduce
                                                                   total HAP emissions by venting emissions to a
                                                                   fuel gas system or process in accordance with
                                                                   Sec.   63.982(d) and the requirements
                                                                   referenced therein.\1\
                                     b. The maximum true vapor    i. Comply with the requirements of subpart WW
                                      pressure of total HAP at     of this part, except as specified in Sec.
                                      the storage temperature is   63.2470; or
                                      <76.6 kilopascals.
                                                                  ii. Reduce total HAP emissions by >=95 percent
                                                                   by weight or to <=20 ppmv of TOC or organic
                                                                   HAP and <=20 ppmv of hydrogen halide and
                                                                   halogen HAP by venting emissions through a
                                                                   closed vent system to any combination of
                                                                   control devices (excluding a flare); or
                                                                  iii. Reduce total organic HAP emissions by
                                                                   venting emissions through a closed vent
                                                                   system to a flare; or
                                                                  iv. Comply with the requirements in Sec.
                                                                   63.2450(e)(4), as applicable; and reduce
                                                                   total HAP emissions by venting emissions to a
                                                                   fuel gas system or process in accordance with
                                                                   Sec.   63.982(d) and the requirements
                                                                   referenced therein.\1\
2. Halogenated vent stream from a    You use a combustion         Meet one of the emission limit options
 Group 1 storage tank.                control device to control    specified in Item 2.a.i or ii. in Table 1 to
                                      organic HAP emissions.       this subpart.

[[Page 49163]]

 
3. Storage tank of any capacity and  Beginning no later than the  Comply with the applicable emission limits
 vapor pressure.                      compliance dates specified   specified in items 1 and 2 of this Table, and
                                      in Sec.   63.2445(i), the    also:
                                      stored liquid contains      i. Reduce emissions of ethylene oxide by
                                      ethylene oxide such that     venting emissions through a closed-vent
                                      the storage tank is          system to a flare; or
                                      considered to be in         ii. Reduce emissions of ethylene oxide by
                                      ethylene oxide service as    venting emissions through a closed-vent
                                      defined in Sec.   63.2550.   system to a control device that reduces
                                                                   ethylene oxide by >=99.9 percent by weight,
                                                                   or to a concentration <1 ppmv for each
                                                                   storage tank vent.
----------------------------------------------------------------------------------------------------------------
\1\ Beginning no later than the compliance dates specified in Sec.   63.2445(g), any flare using fuel gas from a
  fuel gas system, of which 50 percent or more of the fuel gas is derived from an MCPU that has processes and/or
  equipment in ethylene oxide service or that produces olefins or polyolefins, as determined on an annual
  average basis, must be in compliance with Sec.   63.2450(e)(5). For purposes of compliance, an MCPU that
  ``produces olefins or polyolefins'' includes only those MCPUs that manufacture ethylene, propylene,
  polyethylene, and/or polypropylene as a product. By-products and impurities as defined in Sec.   63.101, as
  well as wastes and trace contaminants, are not considered products.

0
28. Table 5 to subpart FFFF of part 63 is revised to read as follows:
    As required in Sec.  63.2475, you must meet each emission limit and 
work practice standard in the following table that applies to your 
transfer racks:

  Table 5 to Subpart FFFF of Part 63--Emission Limits and Work Practice
                      Standards for Transfer Racks
------------------------------------------------------------------------
        For each . . .                       You must . . .
------------------------------------------------------------------------
1. Group 1 transfer rack.....  a. Reduce emissions of total organic HAP
                                by >=98 percent by weight or to an
                                outlet concentration <=20 ppmv as
                                organic HAP or TOC by venting emissions
                                through a closed-vent system to any
                                combination of control devices (except a
                                flare); or
                               b. Reduce emissions of total organic HAP
                                by venting emissions through a closed-
                                vent system to a flare; or
                               c. Comply with the requirements in Sec.
                                63.2450(e)(4), as applicable; and reduce
                                emissions of total organic HAP by
                                venting emissions to a fuel gas system
                                or process in accordance with Sec.
                                63.982(d) and the requirements
                                referenced therein;\1\ or
                               d. Use a vapor balancing system designed
                                and operated to collect organic HAP
                                vapors displaced from tank trucks and
                                railcars during loading and route the
                                collected HAP vapors to the storage tank
                                from which the liquid being loaded
                                originated or to another storage tank
                                connected by a common header.
2. Halogenated Group 1         a. Use a halogen reduction device after
 transfer rack vent stream      the combustion device to reduce
 for which you use a            emissions of hydrogen halide and halogen
 combustion device to control   HAP by >=99 percent by weight, to <=0.45
 organic HAP emissions.         kg/hr, or to <=20 ppmv; or
                               b. Use a halogen reduction device before
                                the combustion device to reduce the
                                halogen atom mass emission rate to
                                <=0.45 kg/hr or to a concentration <=20
                                ppmv.
------------------------------------------------------------------------
\1\ Beginning no later than the compliance dates specified in Sec.
  63.2445(g), any flare using fuel gas from a fuel gas system, of which
  50 percent or more of the fuel gas is derived from an MCPU that has
  processes and/or equipment in ethylene oxide service or that produces
  olefins or polyolefins, as determined on an annual average basis, must
  be in compliance with Sec.   63.2450(e)(5). For purposes of
  compliance, an MCPU that ``produces olefins or polyolefins'' includes
  only those MCPUs that manufacture ethylene, propylene, polyethylene,
  and/or polypropylene as a product. By-products and impurities as
  defined in Sec.   63.101, as well as wastes and trace contaminants,
  are not considered products.

0
29. Table 6 to subpart FFFF of part 63 is revised to read as follows:
    As required in Sec.  63.2480, you must meet each requirement in the 
following table that applies to your equipment leaks:

                      Table 6 to Subpart FFFF of Part 63--Requirements for Equipment Leaks
----------------------------------------------------------------------------------------------------------------
           For all . . .              And that is part of . . .                   You must . . .
----------------------------------------------------------------------------------------------------------------
1. Equipment that is in organic HAP  a. Any MCPU................  i. Comply with the requirements of subpart UU
 service.                                                          of this part and the requirements referenced
                                                                   therein, except as specified in Sec.
                                                                   63.2480(b) and (d) through (f); or
                                                                  ii. Comply with the requirements of subpart H
                                                                   of this part and the requirements referenced
                                                                   therein, except as specified in Sec.
                                                                   63.2480(b) and (d) through (f); or
                                                                  iii. Comply with the requirements of 40 CFR
                                                                   part 65, subpart F, and the requirements
                                                                   referenced therein, except as specified in
                                                                   Sec.   63.2480(c), and (d) through (f).
2. Equipment that is in organic HAP  a. Any MCPU................  i. Comply with the requirements of subpart UU
 service at a new source.                                          of this part and the requirements referenced
                                                                   therein, except as specified in Sec.
                                                                   63.2480(b)(6) and (7), (e), and (f); or
                                                                  ii. Comply with the requirements of 40 CFR
                                                                   part 65, subpart F, except as specified in
                                                                   Sec.   63.2480(c)(10) and (11), (e), and (f).
3. Equipment that is in ethylene     a. Any MCPU................  i. Beginning no later than the compliance
 oxide service as defined in Sec.                                  dates specified in Sec.   63.2445(i), comply
 63.2550.                                                          with the requirements of subpart UU of this
                                                                   part and the requirements referenced therein,
                                                                   except as specified in Sec.   63.2493(d) and
                                                                   (e); or

[[Page 49164]]

 
                                                                  ii. Beginning no later than the compliance
                                                                   dates specified in Sec.   63.2445(i), comply
                                                                   with the requirements of subpart H of this
                                                                   part and the requirements referenced therein,
                                                                   except as specified in Sec.   63.2493(d) and
                                                                   (e);
                                                                  iii. Beginning no later than the compliance
                                                                   dates specified in Sec.   63.2445(i), comply
                                                                   with the requirements of 40 CFR part 65,
                                                                   subpart F, and the requirements referenced
                                                                   therein, except as specified in Sec.
                                                                   63.2493(d) and (e).
----------------------------------------------------------------------------------------------------------------

0
30. Table 10 to subpart FFFF of part 63 is revised to read as follows:
    As required in Sec.  63.2490, you must meet each requirement in the 
following table that applies to your heat exchange systems:

  Table 10 to Subpart FFFF of Part 63--Work Practice Standards for Heat
                            Exchange Systems
------------------------------------------------------------------------
        For each . . .                       You must . . .
------------------------------------------------------------------------
Heat exchange system, as       a. Comply with the requirements of Sec.
 defined in Sec.   63.101.      63.104 and the requirements referenced
                                therein, except as specified in Sec.
                                63.2490(b) and (c); or
                               b. Comply with the requirements in Sec.
                                63.2490(d).
------------------------------------------------------------------------

0
31. Table 12 to subpart FFFF of part 63 is revised to read as follows:
    As specified in Sec.  63.2540, the parts of the general provisions 
that apply to you are shown in the following table:

Table 12 to Subpart FFFF of Part 63--Applicability of General Provisions
                             to Subpart FFFF
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          Citation                   Subject             Explanation
------------------------------------------------------------------------
Sec.   63.1.................  Applicability.......  Yes.
Sec.   63.2.................  Definitions.........  Yes.
Sec.   63.3.................  Units and             Yes.
                               Abbreviations.
Sec.   63.4.................  Prohibited            Yes.
                               Activities.
Sec.   63.5.................  Construction/         Yes.
                               Reconstruction.
Sec.   63.6(a)..............  Applicability.......  Yes.
Sec.   63.6(b)(1)-(4).......  Compliance Dates for  Yes.
                               New and
                               Reconstructed
                               sources.
Sec.   63.6(b)(5)...........  Notification........  Yes.
Sec.   63.6(b)(6)...........  [Reserved]..........  ....................
Sec.   63.6(b)(7)...........  Compliance Dates for  Yes.
                               New and
                               Reconstructed Area
                               Sources That Become
                               Major.
Sec.   63.6(c)(1)-(2).......  Compliance Dates for  Yes.
                               Existing Sources.
Sec.   63.6(c)(3)-(4).......  [Reserved]..........  ....................
Sec.   63.6(c)(5)...........  Compliance Dates for  Yes.
                               Existing Area
                               Sources That Become
                               Major.
Sec.   63.6(d)..............  [Reserved]..........  ....................
Sec.   63.6(e)(1)(i)........  Operation &           Yes, before August
                               Maintenance.          12, 2023.
                                                    No, beginning on and
                                                     after August 12,
                                                     2023. See Sec.
                                                     63.2450(u) for
                                                     general duty
                                                     requirement.
Sec.   63.6(e)(1)(ii).......  Operation &           Yes, before August
                               Maintenance.          12, 2023.
                                                    No, beginning on and
                                                     after August 12,
                                                     2023.
Sec.   63.6(e)(1)(iii)......  Operation &           Yes.
                               Maintenance.
Sec.   63.6(e)(2)...........  [Reserved]..........  ....................
Sec.   63.6(e)(3)(i), (iii),  Startup, Shutdown,    Yes, before August
 and (v) through (viii).       Malfunction Plan      12, 2023, except
                               (SSMP).               information
                                                     regarding Group 2
                                                     emission points and
                                                     equipment leaks is
                                                     not required in the
                                                     SSMP, as specified
                                                     in Sec.
                                                     63.2525(j). No,
                                                     beginning on and
                                                     after August 12,
                                                     2023.
Sec.   63.6(e)(3)(iii) and    Recordkeeping and     No, see Sec.
 (iv).                         Reporting During      63.2525 for
                               SSM.                  recordkeeping
                                                     requirements and
                                                     Sec.
                                                     63.2520(e)(4) for
                                                     reporting
                                                     requirements.
Sec.   63.6(e)(3)(ix).......  SSMP incorporation    Yes, before August
                               into title V permit.  12, 2023. No
                                                     beginning on and
                                                     after August 12,
                                                     2023.
Sec.   63.6(f)(1)...........  Compliance With Non-  No. See Sec.
                               Opacity Standards     63.2445(g) through
                               Except During SSM.    (i).
Sec.   63.6(f)(2)-(3).......  Methods for           Yes.
                               Determining
                               Compliance.
Sec.   63.6(g)(1)-(3).......  Alternative Standard  Yes.
Sec.   63.6(h)(1)...........  Compliance with       No. See Sec.
                               Opacity Standards     63.2445(g) through
                               Except During SSM.    (i).

[[Page 49165]]

 
Sec.   63.6(h)(2)-(9).......  Opacity/Visible       Only for flares for
                               Emission (VE)         which Method 22 of
                               Standards.            40 CFR part 60,
                                                     appendix A-7,
                                                     observations are
                                                     required as part of
                                                     a flare compliance
                                                     assessment.
Sec.   63.6(i)(1)-(14), and   Compliance Extension  Yes.
 (16).
Sec.   63.6(j)..............  Presidential          Yes.
                               Compliance
                               Exemption.
Sec.   63.7(a)(1)-(2).......  Performance Test      Yes, except
                               Dates.                substitute 150 days
                                                     for 180 days.
Sec.   63.7(a)(3)...........  Section 114           Yes, and this
                               Authority.            paragraph also
                                                     applies to flare
                                                     compliance
                                                     assessments as
                                                     specified under
                                                     Sec.
                                                     63.997(b)(2).
Sec.   63.7(a)(4)...........  Force Majeure.......  Yes.
Sec.   63.7(b)(1)...........  Notification of       Yes.
                               Performance Test.
Sec.   63.7(b)(2)...........  Notification of       Yes.
                               Rescheduling.
Sec.   63.7(c)..............  Quality Assurance/    Yes, except the test
                               Test Plan.            plan must be
                                                     submitted with the
                                                     notification of the
                                                     performance test if
                                                     the control device
                                                     controls batch
                                                     process vents.
Sec.   63.7(d)..............  Testing Facilities..  Yes.
Sec.   63.7(e)(1)...........  Conditions for        Yes, before August
                               Conducting            12, 2023 except
                               Performance Tests.    that performance
                                                     tests for batch
                                                     process vents must
                                                     be conducted under
                                                     worst-case
                                                     conditions as
                                                     specified in Sec.
                                                     63.2460. No,
                                                     beginning on and
                                                     after August 12,
                                                     2023. See Sec.
                                                     63.2450(g)(6).
Sec.   63.7(e)(2)...........  Conditions for        Yes.
                               Conducting
                               Performance Tests.
Sec.   63.7(e)(3)...........  Test Run Duration...  Yes.
Sec.   63.7(e)(4)...........  Administrator's       Yes.
                               Authority to
                               Require Testing.
Sec.   63.7(f)..............  Alternative Test      Yes.
                               Method.
Sec.   63.7(g)..............  Performance Test      Yes, except this
                               Data Analysis.        subpart specifies
                                                     how and when the
                                                     performance test
                                                     and performance
                                                     evaluation results
                                                     are reported.
Sec.   63.7(h)..............  Waiver of Tests.....  Yes.
Sec.   63.8(a)(1)...........  Applicability of      Yes.
                               Monitoring
                               Requirements.
Sec.   63.8(a)(2)...........  Performance           Yes.
                               Specifications.
Sec.   63.8(a)(3)...........  [Reserved]..........  ....................
Sec.   63.8(a)(4)...........  Monitoring with       Yes, except for
                               Flares.               flares subject to
                                                     Sec.
                                                     63.2450(e)(5).
Sec.   63.8(b)(1)...........  Monitoring..........  Yes.
Sec.   63.8(b)(2)-(3).......  Multiple Effluents    Yes.
                               and Multiple
                               Monitoring Systems.
Sec.   63.8(c)(1)...........  Monitoring System     Yes.
                               Operation and
                               Maintenance.
Sec.   63.8(c)(1)(i)........  Routine and           Yes, before August
                               Predictable SSM.      12, 2023. No,
                                                     beginning on and
                                                     after August 12,
                                                     2023.
Sec.   63.8(c)(1)(ii).......  CMS malfunction not   Yes.
                               in SSM plan.
Sec.   63.8(c)(1)(iii)......  Compliance with       Yes, before August
                               Operation and         12, 2023. No,
                               Maintenance           beginning on and
                               Requirements.         after August 12,
                                                     2023.
Sec.   63.8(c)(2)-(3).......  Monitoring System     Yes.
                               Installation.
Sec.   63.8(c)(4)...........  CMS Requirements....  Only for CEMS.
                                                     Requirements for
                                                     CPMS are specified
                                                     in referenced
                                                     subparts G and SS
                                                     of this part.
                                                     Requirements for
                                                     COMS do not apply
                                                     because this
                                                     subpart does not
                                                     require continuous
                                                     opacity monitoring
                                                     systems (COMS).
Sec.   63.8(c)(4)(i)........  COMS Measurement and  No; this subpart
                               Recording Frequency.  does not require
                                                     COMS.
Sec.   63.8(c)(4)(ii).......  CEMS Measurement and  Yes.
                               Recording Frequency.
Sec.   63.8(c)(5)...........  COMS Minimum          No. This subpart
                               Procedures.           does not contain
                                                     opacity or VE
                                                     limits.
Sec.   63.8(c)(6)...........  CMS Requirements....  Only for CEMS;
                                                     requirements for
                                                     CPMS are specified
                                                     in referenced
                                                     subparts G and SS
                                                     of this part.
                                                     Requirements for
                                                     COMS do not apply
                                                     because this
                                                     subpart does not
                                                     require COMS.
Sec.   63.8(c)(7)-(8).......  CMS Requirements....  Only for CEMS.
                                                     Requirements for
                                                     CPMS are specified
                                                     in referenced
                                                     subparts G and SS
                                                     of this part.
                                                     Requirements for
                                                     COMS do not apply
                                                     because this
                                                     subpart does not
                                                     require COMS.
Sec.   63.8(d)(1)...........  CMS Quality Control.  Only for CEMS.
Sec.   63.8(d)(2)...........  CMS Quality Control.  Only for CEMS.
Sec.   63.8(d)(3)...........  CMS Quality Control.  Yes, only for CEMS
                                                     before August 12,
                                                     2023. No, beginning
                                                     on and after August
                                                     12, 2023. See Sec.
                                                      63.2450(j)(6).
Sec.   63.8(e)..............  CMS Performance       Only for CEMS,
                               Evaluation.           except this subpart
                                                     specifies how and
                                                     when the
                                                     performance
                                                     evaluation results
                                                     are reported.
                                                     Section
                                                     63.8(e)(5)(ii) does
                                                     not apply because
                                                     this subpart does
                                                     not require COMS.
Sec.   63.8(f)(1)-(5).......  Alternative           Yes, except you may
                               Monitoring Method.    also request
                                                     approval using the
                                                     precompliance
                                                     report.
Sec.   63.8(f)(6)...........  Alternative to        Only applicable when
                               Relative Accuracy     using CEMS to
                               Test.                 demonstrate
                                                     compliance,
                                                     including the
                                                     alternative
                                                     standard in Sec.
                                                     63.2505.

[[Page 49166]]

 
Sec.   63.8(g)(1)-(4).......  Data Reduction......  Only when using
                                                     CEMS, including for
                                                     the alternative
                                                     standard in Sec.
                                                     63.2505, except
                                                     that the
                                                     requirements for
                                                     COMS do not apply
                                                     because this
                                                     subpart has no
                                                     opacity or VE
                                                     limits, and Sec.
                                                     63.8(g)(2) does not
                                                     apply because data
                                                     reduction
                                                     requirements for
                                                     CEMS are specified
                                                     in Sec.
                                                     63.2450(j).
Sec.   63.8(g)(5)...........  Data Reduction......  No. Requirements for
                                                     CEMS are specified
                                                     in Sec.
                                                     63.2450(j).
                                                     Requirements for
                                                     CPMS are specified
                                                     in referenced
                                                     subparts G and SS
                                                     of this part.
Sec.   63.9(a)..............  Notification          Yes.
                               Requirements.
Sec.   63.9(b)(1)-(5).......  Initial               Yes.
                               Notifications.
Sec.   63.9(c)..............  Request for           Yes.
                               Compliance
                               Extension.
Sec.   63.9(d)..............  Notification of       Yes.
                               Special Compliance
                               Requirements for
                               New Source.
Sec.   63.9(e)..............  Notification of       Yes.
                               Performance Test.
Sec.   63.9(f)..............  Notification of VE/   No.
                               Opacity Test.
Sec.   63.9(g)..............  Additional            Only for CEMS.
                               Notifications When    Section 63.9(g)(2)
                               Using CMS.            does not apply
                                                     because this
                                                     subpart does not
                                                     require COMS.
63.9(h)(1)-(6)..............  Notification of       Yes, except Sec.
                               Compliance Status.    63.9(h)(2)(i)(A)
                                                     through (G) and
                                                     (h)(2)(ii) do not
                                                     apply because Sec.
                                                      63.2520(d)
                                                     specifies the
                                                     required contents
                                                     and due date of the
                                                     notification of
                                                     compliance status
                                                     report.
Sec.   63.9(i)..............  Adjustment of         Yes.
                               Submittal Deadlines.
Sec.   63.9(j)..............  Change in Previous    No, Sec.
                               Information.          63.2520(e)
                                                     specifies reporting
                                                     requirements for
                                                     process changes.
Sec.   63.10(a).............  Recordkeeping/        Yes.
                               Reporting.
Sec.   63.10(b)(1)..........  Recordkeeping/        Yes.
                               Reporting.
Sec.   63.10(b)(2)(i).......  Records related to    No, see Sec.  Sec.
                               startup and           63.2450(e) and
                               shutdown.             63.2525 for
                                                     recordkeeping
                                                     requirements.
Sec.   63.10(b)(2)(ii)......  Recordkeeping         Yes, before August
                               relevant to SSM       12, 2023. No,
                               periods and CMS.      beginning on and
                                                     after August 12,
                                                     2023. See Sec.
                                                     63.2525(h) and (l).
Sec.   63.10(b)(2)(iii).....  Records related to    Yes.
                               maintenance of air
                               pollution control
                               equipment.
Sec.   63.10(b)(2)(iv) and    Recordkeeping         Yes, before August
 (v).                          relevant to SSM       12, 2023. No,
                               period.               beginning on and
                                                     after August 12,
                                                     2023.
Sec.   63.10(b)(2)(vi)......  CMS Records.........  Before August 12,
                                                     2023, yes but only
                                                     for CEMS;
                                                     requirements for
                                                     CPMS are specified
                                                     in referenced
                                                     subparts G and SS
                                                     of this part.
                                                     Beginning on and
                                                     after August 12,
                                                     2023, yes for CEMS
                                                     and CPMS for flares
                                                     subject to Sec.
                                                     63.2450(e)(5).
Sec.   63.10(b)(2)(x) and     CMS Records.........  Only for CEMS;
 (xi).                                               requirements for
                                                     CPMS are specified
                                                     in referenced
                                                     subparts G and SS
                                                     of this part.
Sec.   63.10(b)(2)(vii)-(ix)  Records.............  Yes.
Sec.   63.10(b)(2)(xii).....  Records.............  Yes.
Sec.   63.10(b)(2)(xiii)....  Records.............  Only for CEMS.
Sec.   63.10(b)(2)(xiv).....  Records.............  Yes.
Sec.   63.10(b)(3)..........  Records.............  Yes.
Sec.   63.10(c)(1)-(6),(9)-   Records.............  Only for CEMS.
 (14).                                               Recordkeeping
                                                     requirements for
                                                     CPMS are specified
                                                     in referenced
                                                     subparts G and SS
                                                     of this part.
Sec.   63.10(c)(7)-(8)......  Records.............  No. Recordkeeping
                                                     requirements are
                                                     specified in Sec.
                                                     63.2525.
Sec.   63.10(c)(15).........  Records.............  Yes, before August
                                                     12, 2023, but only
                                                     for CEMS. No,
                                                     beginning on and
                                                     after August 12,
                                                     2023.
Sec.   63.10(d)(1)..........  General Reporting     Yes.
                               Requirements.
Sec.   63.10(d)(2)..........  Report of             Yes, before October
                               Performance Test      13, 2020. No,
                               Results.              beginning on and
                                                     after October 13,
                                                     2020.
Sec.   63.10(d)(3)..........  Reporting Opacity or  No.
                               VE Observations.
Sec.   63.10(d)(4)..........  Progress Reports....  Yes.
Sec.   63.10(d)(5)(i).......  Periodic Startup,     No, Sec.
                               Shutdown, and         63.2520(e)(4) and
                               Malfunction Reports.  (5) specify the SSM
                                                     reporting
                                                     requirements.
Sec.   63.10(d)(5)(ii)......  Immediate SSM         No.
                               Reports.
Sec.   63.10(e)(1)..........  Additional CEMS       Yes.
                               Reports.
Sec.   63.10(e)(2)(i).......  Additional CMS        Only for CEMS,
                               Reports.              except this subpart
                                                     specifies how and
                                                     when the
                                                     performance
                                                     evaluation results
                                                     are reported.
Sec.   63.10(e)(2)(ii)......  Additional COMS       No. This subpart
                               Reports.              does not require
                                                     COMS.
Sec.   63.10(e)(3)..........  Reports.............  No. Reporting
                                                     requirements are
                                                     specified in Sec.
                                                     63.2520.
Sec.   63.10(e)(3)(i)-(iii).  Reports.............  No. Reporting
                                                     requirements are
                                                     specified in Sec.
                                                     63.2520.
Sec.   63.10(e)(3)(iv)-(v)..  Excess Emissions      No. Reporting
                               Reports.              requirements are
                                                     specified in Sec.
                                                     63.2520.
Sec.   63.10(e)(3)(iv)-(v)..  Excess Emissions      No. Reporting
                               Reports.              requirements are
                                                     specified in Sec.
                                                     63.2520.
Sec.   63.10(e)(3)(vi)-       Excess Emissions      No. Reporting
 (viii).                       Report and Summary    requirements are
                               Report.               specified in Sec.
                                                     63.2520.

[[Page 49167]]

 
Sec.   63.10(e)(4)..........  Reporting COMS data.  No.
Sec.   63.10(f).............  Waiver for            Yes.
                               Recordkeeping/
                               Reporting.
Sec.   63.11................  Control device        Yes, except for
                               requirements for      flares subject to
                               flares and work       Sec.
                               practice              63.2450(e)(5).
                               requirements for
                               equipment leaks.
Sec.   63.12................  Delegation..........  Yes.
Sec.   63.13................  Addresses...........  Yes.
Sec.   63.14................  Incorporation by      Yes.
                               Reference.
Sec.   63.15................  Availability of       Yes.
                               Information.
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