Document ID: EPA-HQ-OAR-2018-0746-0001
Agency: epa
Document Type: Proposed Rule
Title: National Emission Standards for Hazardous Air Pollutants: Miscellaneous Organic Chemical Manufacturing Residual Risk and Technology Review
Posted Date: 2019-12-17T05:00Z

[Federal Register Volume 84, Number 242 (Tuesday, December 17, 2019)]
[Proposed Rules]
[Pages 69182-69269]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-24573]

[[Page 69181]]

Vol. 84

Tuesday,

No. 242

December 17, 2019

Part III

Environmental Protection Agency

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40 CFR Part 63

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

  Federal Register / Vol. 84 , No. 242 / Tuesday, December 17, 2019 / 
Proposed Rules  

[[Page 69182]]

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 ENVIRONMENTAL PROTECTION AGENCY

 40 CFR Part 63

[EPA-HQ-OAR-2018-0746; FRL-10001-98-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: Proposed rule.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing 
amendments to the National Emission Standards for Hazardous Air 
Pollutants (NESHAP) for the Miscellaneous Organic Chemical 
Manufacturing source category. The EPA is proposing decisions 
concerning the residual risk and technology review (RTR), including 
proposing amendments pursuant to the technology review for equipment 
leaks and heat exchange systems, and also proposing amendments pursuant 
to the risk review to specifically address ethylene oxide emissions 
from storage tanks, process vents, and equipment leaks. The EPA is also 
proposing amendments 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. Lastly, the EPA is proposing 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; and add provisions for electronic 
reporting of performance test results and reports, performance 
evaluation reports, and compliance reports. We estimate that, if 
finalized, these proposed amendments (not including the potential 
excess emission reductions from flares) would reduce hazardous air 
pollutants (HAP) emissions from this source category by 116 tons per 
year (tpy) and would reduce ethylene oxide emissions from this source 
category by approximately 10 tpy.

DATES: Comments. Comments must be received on or before January 31, 
2020. Under the Paperwork Reduction Act (PRA), comments on the 
information collection provisions are best assured of consideration if 
the Office of Management and Budget (OMB) receives a copy of your 
comments on or before January 16, 2020.
    Public hearing. The EPA is planning to hold at least one public 
hearing in response to this proposed action. Information about the 
hearing, including location, date, and time, along with instructions on 
how to register to speak at the hearing, will be published in a second 
Federal Register document and posted at https://www.epa.gov/stationary-sources-air-pollution/miscellaneous-organic-chemical-manufacturing-national-emission. See SUPPLEMENTARY INFORMATION for information on 
registering and attending a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2018-0746, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(our preferred method). Follow the online instructions for submitting 
comments.
     Email: a-and-r-docket@epa.gov. Include Docket ID No. EPA-
HQ-OAR-2018-0746 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2018-0746.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2018-0746, Mail Code 28221T, 1200 
Pennsylvania Avenue NW, Washington, DC 20460.
     Hand/Courier Delivery: EPA Docket Center, WJC West 
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. 
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m., Monday-
Friday (except federal holidays).
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the SUPPLEMENTARY 
INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
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; fax number: (919) 541-0516; 
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; fax number: (919) 541-0840; and email address: 
woody.matthew@epa.gov. For questions about monitoring and testing 
requirements, contact Ms. Gerri Garwood, Sector Policies and Programs 
Division (D243-05), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-2406; fax number: (919) 541-4991; 
and email address: garwood.gerri@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 (Mail Code 2227A), 1200 
Pennsylvania Avenue NW, Washington, DC 20460; telephone number: (202) 
564-1395; and email address: cox.john@epa.gov.

SUPPLEMENTARY INFORMATION: 
    Public hearing. The EPA is planning to hold at least one public 
hearing in response to this proposed action. Information about the 
hearing, including location, date, and time, along with instructions on 
how to register to speak at the hearing will be published in a second 
Federal Register document.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2018-0746. All documents in the docket are 
listed in Regulations.gov. Although listed, some information is not 
publicly available, e.g., Confidential Business Information (CBI) or 
other information whose disclosure is restricted by statute. Certain 
other material, such as copyrighted material, is not placed on the 
internet and will be publicly available only in hard copy. Publicly 
available docket materials are available either electronically in 
Regulations.gov or in hard copy at the EPA Docket Center, Room 3334, 
WJC West Building, 1301 Constitution Avenue NW, Washington, DC. The 
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Public 
Reading Room is (202) 566-1744, and the telephone number for the EPA 
Docket Center is (202) 566-1742.

[[Page 69183]]

    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2018-0746. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at https://www.regulations.gov/, including any personal 
information provided, unless the comment includes information claimed 
to be CBI or other information whose disclosure is restricted by 
statute. Do not submit information that you consider to be CBI or 
otherwise protected through https://www.regulations.gov/ or email. This 
type of information should be submitted by mail as discussed below.
    The EPA may publish any comment received to its public docket. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. The EPA 
will generally not consider comments or comment contents located 
outside of the primary submission (i.e., on the Web, cloud, or other 
file sharing system). For additional submission methods, the full EPA 
public comment policy, information about CBI or multimedia submissions, 
and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    The https://www.regulations.gov/ website allows you to submit your 
comment anonymously, which means the EPA will not know your identity or 
contact information unless you provide it in the body of your comment. 
If you send an email comment directly to the EPA without going through 
https://www.regulations.gov/, your email address will be automatically 
captured and included as part of the comment that is placed in the 
public docket and made available on the internet. If you submit an 
electronic comment, the EPA recommends that you include your name and 
other contact information in the body of your comment and with any 
digital storage media you submit. If the EPA cannot read your comment 
due to technical difficulties and cannot contact you for clarification, 
the EPA may not be able to consider your comment. Electronic files 
should not include special characters or any form of encryption and be 
free of any defects or viruses. For additional information about the 
EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
    Submitting CBI. Do not submit information containing CBI to the EPA 
through https://www.regulations.gov/ or email. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
any digital storage media that you mail to the EPA, mark the outside of 
the digital storage media as CBI and then identify electronically 
within the digital storage media the specific information that is 
claimed as CBI. In addition to one complete version of the comments 
that includes information claimed as CBI, you must submit a copy of the 
comments that does not contain the information claimed as CBI directly 
to the public docket through the procedures outlined in Instructions 
above. If you submit any digital storage media that does not contain 
CBI, mark the outside of the digital storage media clearly that it does 
not contain CBI. Information not marked as CBI will be included in the 
public docket and the EPA's electronic public docket without prior 
notice. Information marked as CBI will not be disclosed except in 
accordance with procedures set forth in 40 Code of Federal Regulations 
(CFR) part 2. Send or deliver information identified as CBI only to the 
following address: OAQPS Document Control Officer (C404-02), OAQPS, 
U.S. Environmental Protection Agency, Research Triangle Park, North 
Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2018-0746.
    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:

ACA American Coatings Association
ACC American Chemistry Council
AEGL acute exposure guideline level
AERMOD air dispersion model used by the HEM-3 model
AFPM American Fuel & Petrochemical Manufacturers
AMEL alternative means of emission limitation
APCD air pollution control device
ATSDR Agency for Toxic Substances and Disease Registry
BAAQMD Bay Area Air Quality Management District
BACT best available control technology
Btu British thermal unit
Btu/scf British thermal unit per standard cubic foot
CAA Clean Air Act
CalEPA California EPA
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CEMS continuous emission monitoring system(s)
CFR Code of Federal Regulations
ECHO Enforcement and Compliance History Online
EIS emissions inventory system
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guideline
ERT Electronic Reporting Tool
FID flame ionization detector
FTIR fourier transfer infrared spectrometry
GACT generally available control technologies
HAPV hazardous air pollutant(s)
HCl hydrochloric acid
HEM-3 Human Exposure Model
HF hydrogen fluoride
HI hazard index
HQ hazard quotient
HRVOC highly reactive volatile organic compounds
ICR Information Collection Request
IRIS Integrated Risk Information System
km kilometer
LAER lowest achievable emission rate
LDAR leak detection and repair
LEL lower explosive limit
MACT maximum achievable control technology
MCPU miscellaneous organic chemical manufacturing process unit
mg/m\3\ milligrams per cubic meter
MIR maximum individual risk
MON Miscellaneous Organic Chemical Manufacturing NESHAP
MPGF multi-point ground flare(s)
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NEI National Emission Inventory
NESHAP national emission standards for hazardous air pollutants
NHVcz net heating value in the combustion zone gas
NHVdil net heating value dilution parameter
NHVvg net heating value of flare vent gas
NRDC Natural Resources Defense Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
OSHA Occupational Safety and Health Administration
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PDF portable document format
PDH propane dehydrogenation
POM polycyclic organic matter
ppm parts per million
ppmw parts per million by weight
ppmv parts per million by volume
PRA Paperwork Reduction Act
PRD pressure relief device(s)
psig pounds per square inch gauge
RACT reasonably available control technology
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RTR residual risk and technology review
SAB Science Advisory Board
SCC source classification code
SSM startup, shutdown, and malfunction
TCEQ Texas Commission on Environmental Quality
TOSHI target organ-specific hazard index
tpy tons per year

[[Page 69184]]

TRIM.FaTE Total Risk Integrated Methodology.Fate, Transport, and 
Ecological Exposure Model
UF uncertainty factor
[micro]g/m\3\ micrograms per cubic meter
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
USGS U.S. Geological Survey
VCS voluntary consensus standards
VOC volatile organic compound(s)

    Organization of this document. The information in this preamble is 
organized as follows below. In particular, section IV of this preamble 
describes the majority of the Agency's rationale for the proposed 
actions in this preamble. Section IV.A of this preamble specifies 
proposed monitoring and operational requirements for a subset of flares 
in the Miscellaneous Organic Chemical Manufacturing source category to 
ensure that the level of control from the original maximum achievable 
control technology (MACT) standards is achieved by these air pollution 
control devices (APCD). To ensure that Clean Air Act (CAA) section 112 
standards continuously apply (Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008)), section IV.A of this preamble also proposes work practice 
standards for periods of SSM for when flares are used as an APCD, 
proposes work practice standards for periods of SSM for certain vent 
streams (i.e., pressure relief device (PRD) releases and maintenance 
vents), and proposes clarifications for vent control bypasses for 
certain vent streams (i.e., closed vent systems containing bypass 
lines, and flares connected to fuel gas systems).
    Section IV.B of this preamble summarizes the results of the risk 
assessment while section IV.C summarizes our proposed decisions 
regarding the results of the risk assessment, and proposes revisions 
for storage tanks, process vents, and equipment leaks to reduce 
emissions of ethylene oxide. Section IV.D of this preamble summarizes 
the results of our technology review, and proposes revisions for heat 
exchange systems and equipment leaks. Section IV.E of this preamble 
summarizes other changes we are proposing, including general regulatory 
language changes related to the removal of SSM exemptions, electronic 
reporting, and other minor clarifications identified as part our review 
of the NESHAP and as part of the other proposed revisions in this 
proposal. Lastly, section IV.F of this preamble summarizes our 
rationale for the compliance dates we are proposing.

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
II. Background
    A. What is the statutory authority for this action?
    B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?
    C. What data collection activities were conducted to support 
this action?
    D. What other relevant background information and data are 
available?
III. Analytical Procedures and Decision-Making
    A. How do we consider risk in our decision-making?
    B. How do we perform the technology review?
    C. How do we estimate post-MACT risk posed by the source 
category?
IV. Analytical Results and Proposed Decisions
    A. What actions are we taking in addition to those identified in 
the risk and technology review?
    B. What are the results of the risk assessment and analyses?
    C. What are our proposed decisions regarding risk acceptability, 
ample margin of safety, and adverse environmental effects?
    D. What are the results and proposed decisions based on our 
technology review?
    E. What other actions are we proposing?
    F. What compliance dates are we proposing?
V. Summary of Cost, Environmental, and Economic Impacts
    A. What are the affected sources?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 13771: Reducing Regulations and Controlling 
Regulatory Costs
    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    H. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR Part 51
    K. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated 
industrial source category that is the subject of this proposal. Table 
1 is not intended to be exhaustive, but rather provides a guide for 
readers regarding the entities that this proposed action is likely to 
affect. The proposed standards, once promulgated, will be directly 
applicable to the affected sources. Federal, state, local, and tribal 
government entities would not be affected by this proposed action. On 
July 16, 1992 (57 FR 31576), pursuant to specific listing requirements 
in CAA section 112(c), the Agency published an initial list of 174 
categories of major and area sources that would be subject to MACT 
emission standards. Following this listing, in a November 7, 1996, 
document (61 FR 57602), the Agency combined 21 of the 174 source 
categories originally defined in the Initial List of Categories of 
Sources Under Section 112(c)(1) of the Clean Air Act Amendments of 1990 
(see 57 FR 31576, July 16, 1992) and Documentation for Developing the 
Initial Source Category List, Final Report (see EPA-450/3-91-030, July 
1992), and other organic chemical processes which were not included in 
the original 174 source category list, into one source category called 
the ``Miscellaneous Organic Chemical Processes'' source category. In a 
November 18, 1999, document (64 FR 63035), the Agency divided the 
``Miscellaneous Organic Chemical Processes'' source category into two 
new source categories called the ``Miscellaneous Organic Chemical 
Manufacturing'' source category and the ``Miscellaneous Coating 
Manufacturing'' source category. The Miscellaneous Organic Chemical 
Manufacturing source category includes any facility engaged in 
benzyltrimethylammonium chloride production, carbonyl sulfide 
production, chelating agents production, chlorinated paraffins 
production, ethylidene norbornene production, explosives production, 
hydrazine production, photographic chemicals production, phthalate 
plasticizers production, rubber chemicals production, symmetrical 
tetrachloropyridine production, oxybisphenoxarsine/1,3-diisocyanate 
production, alkyd resins production, polyester resins production, 
polyvinyl alcohol production, polyvinyl acetate emulsions production, 
polyvinyl butyral production, polymerized vinylidene chloride 
production, polymethyl methacrylate production, maleic

[[Page 69185]]

anhydride copolymers production, or any other organic chemical 
processes not covered by another MACT standard. Many of these organic 
chemical processes involve similar process equipment, similar emission 
points and control equipment, and are in many cases co-located with 
other source categories. For more information about the Miscellaneous 
Organic Chemical Manufacturing source category, see section II.B of 
this preamble.

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

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

    In addition to being available in the docket, an electronic copy of 
this action is available on the internet. Following signature by the 
EPA Administrator, the EPA will post a copy of this proposed action at 
https://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 
of the proposal and key technical documents at this same website. 
Information on the overall RTR program is available at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
    A redline version of the regulatory language that incorporates the 
proposed changes is available in the docket for this action (Docket ID 
No. EPA-HQ-OAR-2018-0746).

II. Background

A. What is the statutory authority for this action?

    The statutory authority for this action is provided by sections 112 
and 301 of the CAA, as amended (42 U.S.C. 7401 et seq.). Section 112 of 
the CAA establishes a two-stage regulatory process to develop standards 
for emissions of HAP from stationary sources. Generally, the first 
stage involves establishing technology-based standards and the second 
stage involves evaluating those standards that are based on MACT to 
determine whether additional standards are needed to address any 
remaining risk associated with HAP emissions. This second stage is 
commonly referred to as the ``residual risk review.'' In addition to 
the residual risk review, the CAA also requires the EPA to review 
standards set under CAA section 112 every 8 years to determine if there 
are ``developments in practices, processes, or control technologies'' 
that may be appropriate to incorporate into the standards. This review 
is commonly referred to as the ``technology review.'' When the two 
reviews are combined into a single rulemaking, it is commonly referred 
to as the ``risk and technology review.'' The discussion that follows 
identifies the most relevant statutory sections and briefly explains 
the contours of the methodology used to implement these statutory 
requirements. A more comprehensive discussion appears in the document 
titled CAA Section 112 Risk and Technology Reviews: Statutory Authority 
and Methodology, in the docket for this rulemaking.
    In the first stage of the CAA section 112 standard setting process, 
the EPA promulgates technology-based standards under CAA section 112(d) 
for categories of sources identified as emitting one or more of the HAP 
listed in CAA section 112(b). Sources of HAP emissions are either major 
sources or area sources, and CAA section 112 establishes different 
requirements for major source standards and area source standards. 
``Major sources'' are those that emit or have the potential to emit 10 
tpy or more of a single HAP or 25 tpy or more of any combination of 
HAP. All other sources are ``area sources.'' For major sources, CAA 
section 112(d)(2) provides that the technology-based NESHAP must 
reflect the maximum degree of emission reductions of HAP achievable 
(after considering cost, energy requirements, and non-air quality 
health and environmental impacts). These standards are commonly 
referred to as MACT standards. CAA section 112(d)(3) also establishes a 
minimum control level for MACT standards, known as the MACT ``floor.'' 
The EPA must also consider control options that are more stringent than 
the floor. Standards more stringent than the floor are commonly 
referred to as beyond-the-floor standards. In certain instances, as 
provided in CAA section 112(h), the EPA may set work practice standards 
where it is not feasible to prescribe or enforce a numerical emission 
standard. For area sources, CAA section 112(d)(5) gives the EPA 
discretion to set standards based on generally available control 
technologies or management practices (GACT standards) in lieu of MACT 
standards.
    The second stage in standard-setting focuses on identifying and 
addressing any remaining (i.e., ``residual'') risk according to CAA 
section 112(f). For source categories subject to MACT standards, 
section 112(f)(2) of the CAA requires the EPA to determine whether 
promulgation of additional standards is needed to provide an ample 
margin of safety to protect public health or to prevent an adverse 
environmental effect. Section 112(d)(5) of the CAA provides that this 
residual risk review is not required for categories of area sources 
subject to GACT standards. Section 112(f)(2)(B) of the CAA further 
expressly preserves the EPA's use of the two-step approach for 
developing standards to address any residual risk and the Agency's 
interpretation of ``ample margin of safety'' developed in the National 
Emissions Standards for Hazardous Air Pollutants: Benzene Emissions 
from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene 
Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery 
Plants (Benzene NESHAP) (54 FR 38044, September 14, 1989). The EPA 
notified Congress in the Risk Report that the Agency intended to use 
the Benzene NESHAP approach in making CAA section 112(f) residual risk 
determinations (EPA-453/R-99-001, p. ES-11). The EPA subsequently 
adopted this approach in its residual risk determinations and the 
United States Court of Appeals for the District of Columbia Circuit 
(the Court) upheld the EPA's interpretation that CAA section 112(f)(2) 
incorporates the approach established in the Benzene NESHAP. See NRDC 
v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008).
    The approach incorporated into the CAA and used by the EPA to 
evaluate residual risk and to develop standards under CAA section 
112(f)(2) is a two-step approach. In the first step, the EPA determines 
whether risks are acceptable. This determination ``considers all health 
information, including risk estimation uncertainty, and includes a 
presumptive

[[Page 69186]]

limit on maximum individual lifetime [cancer] risk (MIR) \1\ of 
approximately 1-in-10 thousand.'' 54 FR 38045, September 14, 1989. If 
risks are unacceptable, the EPA must determine the emissions standards 
necessary to reduce risk to an acceptable level without considering 
costs. In the second step of the approach, the EPA considers whether 
the emissions standards provide an ample margin of safety to protect 
public health ``in consideration of all health information, including 
the number of persons at risk levels higher than approximately 1-in-1 
million, as well as other relevant factors, including costs and 
economic impacts, technological feasibility, and other factors relevant 
to each particular decision.'' Id. The EPA must promulgate emission 
standards necessary to provide an ample margin of safety to protect 
public health or determine that the standards being reviewed provide an 
ample margin of safety without any revisions. After conducting the 
ample margin of safety analysis, we consider whether a more stringent 
standard is necessary to prevent, taking into consideration costs, 
energy, safety, and other relevant factors, an adverse environmental 
effect.
---------------------------------------------------------------------------

    \1\ Although defined as ``maximum individual risk,'' MIR refers 
only to cancer risk. MIR, one metric for assessing cancer risk, is 
the estimated risk if an individual were exposed to the maximum 
level of a pollutant for a lifetime.
---------------------------------------------------------------------------

    CAA section 112(d)(6) separately requires the EPA to review 
standards promulgated under CAA section 112 and revise them ``as 
necessary (taking into account developments in practices, processes, 
and control technologies)'' no less often than every 8 years. In 
conducting this review, which we call the ``technology review,'' the 
EPA is not required to recalculate the MACT floor. Natural Resources 
Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008). 
Association of Battery Recyclers, Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 
2013). The EPA may consider cost in deciding whether to revise the 
standards pursuant to CAA section 112(d)(6).

B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?

    The current NESHAP, herein called the Miscellaneous Organic 
Chemical Manufacturing NESHAP (MON) for the Miscellaneous Organic 
Chemical Manufacturing source category was promulgated on November 10, 
2003 (68 FR 63852), and codified at 40 CFR part 63, subpart FFFF. As 
promulgated in 2003, and further amended on July 1, 2005 (70 FR 38562), 
and July 14, 2006 (71 FR 40316), 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); it processes, 
uses, or generates any of the organic HAP described in 40 CFR 
63.2435(b)(2); and, 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, 
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, the EPA identified 201 miscellaneous 
organic chemical manufacturing facilities in operation and subject to 
the MON standards, herein referred to as ``MON facilities'', using 
methods described in section II.C of this preamble. A complete list of 
known MON facilities is available in Appendix 1 of the document titled 
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.

C. What data collection activities were conducted to support this 
action?

    The EPA used several sources to develop the list of existing MON 
facilities. All facilities in the 2014 National Emissions Inventory 
(NEI) and the 2014 Toxics Release Inventory with a primary facility 
NAICS code beginning with 325, representing the chemical manufacturing 
sector, were queried to create a comprehensive base facility list. The 
list was also supplemented using the Office of Enforcement and 
Compliance Assurance's (OECA) Enforcement and Compliance History Online 
(ECHO) tool (https://echo.epa.gov) and chemical sector facility lists 
provided internally from the EPA's records. This starting chemical 
manufacturing sector facility list included over 5,000 unique 
facilities, 201 of which we found to be subject to the MON.
    To determine which facilities on the comprehensive chemical 
manufacturing sector facility list were subject to the MON, title V air 
permits were obtained from each state's online database. In cases where 
the online database was incomplete, the Region and/or state was 
contacted for help in obtaining the air permits, and internet searches 
were performed to determine the status of the facility (e.g., open, 
permanently closed, sold, etc.). The list was also shared with the 
American Chemistry Council (ACC) and the American Coatings Association 
(ACA) for voluntary input on rule applicability. This review and 
analysis produced the final facility list of 201 MON facilities. For 
MON facilities that reported emissions of ethylene oxide, we not only 
reviewed the air permit, but we also contacted facilities to verify 
process and operating information.\2\
---------------------------------------------------------------------------

    \2\ As discussed in section IV.C.2 of this preamble, we 
specifically address ethylene oxide emissions from storage tanks, 
process vents, and equipment leaks.
---------------------------------------------------------------------------

    In November 2018, the EPA issued a request, pursuant to CAA section 
114, to gather information about process equipment, control 
technologies, and emissions, and requested performance testing for 
certain pollutants for one MCPU source emitting ethylene oxide. The 
facility completed the survey and submitted responses (and follow-up 
responses) to the EPA between January 2019 and February 2019. The 
results of the performance testing were received on September 3, 2019, 
and, therefore, were not included in the risk analysis. The Agency has 
made the results publicly available in the docket for this rulemaking 
to provide the public with an opportunity to review the data before 
promulgation of the rule. Before final promulgation of this rulemaking, 
the EPA intends 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 in this 
proposed action. The information not claimed as CBI by respondents and 
received in time to be included in this proposal is available in

[[Page 69187]]

the memorandum titled Data Received from Information Collection Request 
for the Miscellaneous Organic Chemical Manufacturing Source Category, 
which is available in the docket for this rulemaking.

D. What other relevant background information and data are available?

    We are relying on technical reports and memoranda that the EPA 
developed for flares used as air pollution control devices in the 
Petroleum Refinery Sector RTR and New Source Performance Standards 
(NSPS) (80 FR 75178, December 1, 2015). These technical reports and 
memoranda can be found in the Petroleum Refinery Sector RTR and NSPS 
rulemaking docket, Docket ID No. EPA-HQ-OAR-2010-0682. The Petroleum 
Refinery Sector docket contains several flare-related technical reports 
and memoranda documenting numerous analyses the EPA conducted to 
develop the final suite of operational and monitoring requirements for 
refinery flares. For completeness of the rulemaking record for this 
action and ease of reference in finding these items in the publicly 
available refinery sector rulemaking docket, we are including a list of 
the most relevant technical support documents in Table 1 of the 
memorandum titled Control Option Impacts for Flares Located in the 
Miscellaneous Organic Chemical Manufacturing Source Category, which is 
available in the docket for this rulemaking.
    In addition, the EPA is incorporating into the docket for this 
rulemaking materials associated with a number of site-specific 
alternative means of emission limitation (AMEL) requests for facilities 
electing to use multi-point ground flares (MPGF) as an APCD. These 
site-specific AMEL requests for MPGF have been approved by the EPA 
because the MPGF can achieve at least equivalent reductions in 
emissions to the underlying flare operational standards in various 
NESHAP and/or NSPS. The EPA receives these AMEL requests because MPGFs 
are designed to operate above the current maximum permitted velocity 
requirements for flares in the General Provisions at 40 CFR 63.11(b). 
Given that the EPA has provided notice and sought comment on certain 
specific AMEL requests, the underlying AMEL requests submitted by 
industry, MPGF test data, technical memorandums, Federal Register 
documents \3\ and other supporting and related material that formed the 
basis of the AMEL requests and approved alternative operating 
conditions have been placed in a publicly available docket at Docket ID 
No. EPA-HQ-OAR-2014-0738. We consider all items in Docket ID No. EPA-
HQ-OAR-2014-0738 part of our rulemaking record as well, given that this 
docket is specific to MPGF AMEL requests. We are, therefore, 
referencing the materials in Docket ID No. EPA-HQ-OAR-2014-0738 for 
this rule.
---------------------------------------------------------------------------

    \3\ 80 FR 8023, February 13, 2015; 80 FR 52426, August 31, 2015; 
81 FR 23480, April 21, 2016; 82 FR 16392, April 4, 2017; 82 FR 
27822, June 19, 2017; and 83 FR 18034, April 25, 2018.
---------------------------------------------------------------------------

    We are also relying on data gathered to support the RTR for 
ethylene production processes, as well as memoranda documenting the 
technology review for those processes. Many of the emission sources for 
ethylene production facilities are similar to MON facilities, and 
several of the control options analyzed for the MON were also analyzed 
for the Ethylene Production RTR. The memoranda and background technical 
information can be found in the Ethylene Production RTR rulemaking 
docket, Docket ID No. EPA-HQ-OAR-2017-0357.
    Furthermore, the risk assessment presented here relies on the use 
of the 2016 updated ethylene oxide unit risk estimate (URE) for 
regulatory purposes. The EPA previously requested comment on the use of 
this URE in the Hydrochloric Acid Production RTR proposed rule (84 FR 
1584, February 4, 2019), the comment period for which closed on April 
26, 2019. The Agency received a number of comments on the use of the 
updated ethylene oxide URE. However, ethylene oxide is not emitted by 
the Hydrochloric Acid Production source category but is emitted by the 
Miscellaneous Organic Chemical Manufacturing source category. 
Therefore, the EPA is incorporating these comments into the docket for 
this rulemaking from Docket ID No. EPA-HQ-OAR-2018-0417 and, along with 
comments received on this proposal, will address all comments in the 
response to comments document of this final rulemaking. Note that all 
comments received in the Hydrochloric Acid Production RTR proposal were 
at least partially related to risks from ethylene oxide, and, 
therefore, we are incorporating all comments from that rulemaking into 
the docket for this action. (Note, additional discussion on the use of 
the 2016 updated URE for ethylene oxide for this regulatory action is 
provided in section IV.C.3 in this preamble.)
    Lastly, the EPA is incorporating into the docket for this 
rulemaking all materials associated with the development of the current 
MON standards from Docket ID No. A-96-04 and Docket ID No. OAR-2003-
0121. Publicly available docket materials are available either 
electronically at https://www.regulations.gov/ or in hard copy at the 
EPA Docket Center, EPA WJC West Building, Room 3334, 1301 Constitution 
Ave. NW, Washington, DC. The Public Reading Room is open from 8:30 a.m. 
to 4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the EPA Docket Center is (202) 566-1742.

III. Analytical Procedures and Decision-Making

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

A. How do we consider risk in our decision-making?

    As discussed in section II.A of this preamble and in the Benzene 
NESHAP, in evaluating and developing standards under CAA section 
112(f)(2), we apply a two-step approach to determine whether or not 
risks are acceptable and to determine if the standards provide an ample 
margin of safety to protect public health. 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.
The Benzene NESHAP approach provides flexibility regarding factors the 
EPA may consider in making determinations and how the EPA may weigh 
those factors for each source category. The EPA conducts a risk 
assessment that provides estimates of the MIR posed by the HAP 
emissions from each source in the source category, the hazard index 
(HI) for chronic exposures to HAP with the potential to cause noncancer 
health effects, and the

[[Page 69188]]

hazard quotient (HQ) for acute exposures to HAP with the potential to 
cause noncancer health effects.\4\ The assessment also provides 
estimates of the distribution of cancer risk within the exposed 
populations, cancer incidence, and an evaluation of the potential for 
an adverse environmental effect. The scope of the EPA's risk analysis 
is consistent with the EPA's response to comments on our policy under 
the Benzene NESHAP where the EPA explained that:
---------------------------------------------------------------------------

    \4\ The MIR is defined as the cancer risk associated with a 
lifetime of exposure at the highest concentration of HAP where 
people are likely to live. The HQ is the ratio of the potential HAP 
exposure concentration to the noncancer dose-response value; the HI 
is the sum of HQs for HAP that affect the same target organ or organ 
system.

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

See 54 FR 38057, September 14, 1989. Thus, the level of the MIR is only 
one factor to be weighed in determining acceptability of risk. The 
Benzene NESHAP explained that ``an MIR of approximately one in 10 
thousand should ordinarily be the upper end of the range of 
acceptability. As risks increase above this benchmark, they become 
presumptively less acceptable under CAA section 112, and would be 
weighed with the other health risk measures and information in making 
an overall judgment on acceptability. Or, the Agency may find, in a 
particular case, that a risk that includes an MIR less than the 
presumptively acceptable level is unacceptable in the light of other 
health risk factors.'' Id. at 38045. In other words, risks that include 
an MIR above 100-in-1 million may be determined to be acceptable, and 
risks with an MIR below that level may be determined to be 
unacceptable, depending on all of the available health information. 
Similarly, with regard to the ample margin of safety analysis, the EPA 
stated in the Benzene NESHAP that: ``EPA believes the relative weight 
of the many factors that can be considered in selecting an ample margin 
of safety can only be determined for each specific source category. 
This occurs mainly because technological and economic factors (along 
with the health-related factors) vary from source category to source 
category.'' Id. at 38061. We also consider the uncertainties associated 
with the various risk analyses, as discussed earlier in this preamble, 
in our determinations of acceptability and ample margin of safety.
    The EPA notes that it has not considered certain health information 
to date in making residual risk determinations. At this time, we do not 
attempt to quantify the HAP risk that may be associated with emissions 
from other facilities that do not include the source category under 
review, mobile source emissions, natural source emissions, persistent 
environmental pollution, or atmospheric transformation in the vicinity 
of the sources in the category.
    The EPA understands the potential importance of considering an 
individual's total exposure to HAP in addition to considering exposure 
to HAP emissions from the source category and facility. We recognize 
that such consideration may be particularly important when assessing 
noncancer risk, where pollutant-specific exposure health reference 
levels (e.g., reference concentrations (RfCs)) are based on the 
assumption that thresholds exist for adverse health effects. For 
example, the EPA recognizes that, although exposures attributable to 
emissions from a source category or facility alone may not indicate the 
potential for increased risk of adverse noncancer health effects in a 
population, the exposures resulting from emissions from the facility in 
combination with emissions from all of the other sources (e.g., other 
facilities) to which an individual is exposed may be sufficient to 
result in an increased risk of adverse noncancer health effects. In May 
2010, the Science Advisory Board (SAB) advised the EPA ``that RTR 
assessments will be most useful to decision makers and communities if 
results are presented in the broader context of aggregate and 
cumulative risks, including background concentrations and contributions 
from other sources in the area.'' \5\
---------------------------------------------------------------------------

    \5\ Recommendations of the SAB Risk and Technology Review 
Methods Panel are provided in their report, which is available at: 
https://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf.
---------------------------------------------------------------------------

    In response to the SAB recommendations, the EPA incorporates 
cumulative risk analyses into its RTR risk assessments, including those 
reflected in this proposal. The Agency (1) conducts facility-wide 
assessments, which include source category emission points, as well as 
other emission points within the facilities; (2) combines exposures 
from multiple sources in the same category that could affect the same 
individuals; and (3) for some persistent and bioaccumulative 
pollutants, analyzes the ingestion route of exposure. In addition, the 
RTR risk assessments consider aggregate cancer risk from all 
carcinogens and aggregated noncancer HQs for all noncarcinogens 
affecting the same target organ or target organ system.
    Although we are interested in placing source category and facility-
wide HAP risk in the context of total HAP risk from all sources 
combined in the vicinity of each source, we are concerned about the 
uncertainties of doing so. Estimates of total HAP risk from emission 
sources other than those that we have studied in depth during this RTR 
review would have significantly greater associated uncertainties than 
the source category or facility-wide estimates. Such aggregate or 
cumulative assessments would compound those uncertainties, making the 
assessments too unreliable.

B. How do we perform the technology review?

    Our technology review focuses on the identification and evaluation 
of developments in practices, processes, and control technologies that 
have occurred since the MACT standards were promulgated. Where we 
identify such developments, we analyze their technical feasibility, 
estimated costs, energy implications, and non-air environmental 
impacts. We also consider the emission reductions associated with 
applying each development. This analysis informs our decision of 
whether it is ``necessary'' to revise the emissions standards. In 
addition, we consider the appropriateness of applying controls to new 
sources versus retrofitting existing sources. For this exercise, we 
consider any of the following to be a ``development'':
     Any add-on control technology or other equipment that was 
not identified and considered during development of the original MACT 
standards;
     Any improvements in add-on control technology or other 
equipment (that were identified and considered during development of 
the original

[[Page 69189]]

MACT standards) that could result in additional emissions reduction;
     Any work practice or operational procedure that was not 
identified or considered during development of the original MACT 
standards;
     Any process change or pollution prevention alternative 
that could be broadly applied to the industry and that was not 
identified or considered during development of the original MACT 
standards; and
     Any significant changes in the cost (including cost-
effectiveness) of applying controls (including controls the EPA 
considered during the development of the original MACT standards).
    In addition to reviewing the practices, processes, and control 
technologies that were considered at the time we originally developed 
(or last updated) the NESHAP, we review a variety of data sources in 
our investigation of potential practices, processes, or controls to 
consider. See sections II.C and II.D of this preamble for information 
on the specific data sources that were reviewed as part of the 
technology review.

C. How do we estimate post-MACT risk posed by the source category?

    In this section, we provide a complete description of the types of 
analyses that we generally perform during the risk assessment process. 
In some cases, we do not perform a specific analysis because it is not 
relevant. For example, in the absence of emissions of HAP known to be 
persistent and bioaccumulative in the environment (PB-HAP), we would 
not perform a multipathway exposure assessment. Where we do not perform 
an analysis, we state that we do not and provide the reason. While we 
present all of our risk assessment methods, we only present risk 
assessment results for the analyses actually conducted (see section 
IV.B of this preamble).
    The EPA conducts a risk assessment that provides estimates of the 
MIR for cancer posed by the HAP emissions from each source in the 
source category, the HI for chronic exposures to HAP with the potential 
to cause noncancer health effects, and the HQ for acute exposures to 
HAP with the potential to cause noncancer health effects. The 
assessment also provides estimates of the distribution of cancer risk 
within the exposed populations, cancer incidence, and an evaluation of 
the potential for an adverse environmental effect. The eight sections 
that follow this paragraph describe how we estimated emissions and 
conducted the risk assessment. The docket for this rulemaking contains 
the following document which provides more information on the risk 
assessment inputs and models: Residual Risk Assessment for the 
Miscellaneous Organic Chemical Manufacturing Source Category in Support 
of the 2019 Risk and Technology Review Proposed Rule. The methods used 
to assess risk (as described in the eight primary steps below) are 
consistent with those described by the EPA in the document reviewed by 
a panel of the EPA's SAB in 2009; \6\ and described in the SAB review 
report issued in 2010. They are also consistent with the key 
recommendations contained in that report.
---------------------------------------------------------------------------

    \6\ U.S. EPA. Risk and Technology Review (RTR) Risk Assessment 
Methodologies: For Review by the EPA's Science Advisory Board with 
Case Studies--MACT I Petroleum Refining Sources and Portland Cement 
Manufacturing, June 2009. EPA-452/R-09-006. https://www3.epa.gov/airtoxics/rrisk/rtrpg.html.
---------------------------------------------------------------------------

1. How did we estimate actual emissions and identify the emissions 
release characteristics?
    The MON facility list was developed as described in section II.C of 
this preamble and consists of 201 facilities. The emissions modeling 
input files were developed using the EPA's 2014 NEI. Two modeling input 
files were developed, one that contains the whole facility emissions 
and one that contains only emissions from MON processes, or the source 
category. For the 201 MON facilities, only 197 had reported HAP 
emissions in the 2014 NEI. Of the four facilities without HAP 
emissions, two had reported no HAP data to the 2014 NEI and two had no 
Emissions Inventory System (EIS) ID and, therefore, no emissions data 
to pull from the NEI. Of the 197 facilities with reported HAP 
emissions, three facilities did not report any HAP emissions that could 
be identified as attributed to MON processes and, therefore, emissions 
data for these three facilities could not be modeled. Therefore, due to 
lack of available data, source category risk modeling was not conducted 
for seven of the 201 MON facilities, which could potentially result in 
an underestimation of risk for the source category. The complete MON 
facility list is available in Appendix 1 of the document titled 
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.
    The EPA created the whole facility modeling file using all HAP 
emissions records from the 2014 NEI for the list of 197 EIS IDs which 
had available HAP data. The NEI data were also used to develop the 
other parameters needed to perform the risk modeling analysis, 
including the emissions release characteristics, such as stack heights, 
stack diameters, flow rates, temperatures, and emission release point 
locations.
    The EPA then created the source category modeling input file by 
identifying the specific NEI emissions records in the whole facility 
modeling input file that are subject to the MON by reviewing the 
facilities' title V air permits, unit source classification code (SCC), 
emission unit descriptions, and process descriptions. The EPA also used 
SCC codes, emission unit descriptions, and process descriptions to 
identify units that are not subject to the MON (e.g., boilers, engines, 
etc.) and removed them from the source category modeling file. In 
general, ambiguous NEI records were assumed to be subject to the MON to 
be conservatively inclusive, with the intention of verifying the rule 
applicability later if the risk analysis revealed these unit emissions 
to be risk drivers for the source category. As mentioned previously, of 
the 197 facilities with reported HAP emissions at the whole facility 
level, three facilities did not report any HAP emissions that could be 
identified as attributed to MON processes and, therefore, emissions 
data for 194 facilities was included in the source category modeling 
file. After determining which NEI records were subject to the MON, the 
record was assigned to an emission process group, identified in Table 
2.

  Table 2--Emission Process Groups Related to the Miscellaneous Organic
                 Chemical Manufacturing Source Category
------------------------------------------------------------------------
                                               Emission process group
  Emission process group abbreviation \1\          description \1\
------------------------------------------------------------------------
PV........................................  Process Vent.
ST........................................  Storage Tank.
TR........................................  Transfer Operation.
HE........................................  Heat Exchange System.
EL........................................  Equipment Leak.
WS........................................  Wastewater.
FL........................................  Flare.
IN \2\....................................  Potential MON Process
                                             Group.\2\
UK \3\....................................  Unknown Process Group.\3\
OT \4\....................................  Non-MON Process Group.\4\
------------------------------------------------------------------------
\1\ Sometimes the record includes co-mingled emissions from more than
  one emission process group due to a shared control device.

[[Page 69190]]

 
\2\ These are emission records at the facility from sources that may
  potentially be subject to the MON, based on their SCC code, emission
  unit description, or process description, but could not be verified
  due to lack of available information.
\3\ These are emission records at the facility from sources that are
  subject to the MON but lack specific details in the NEI record to
  allow identification of an appropriate emission process group.
\4\ These are emission records at the facility from sources that are not
  subject to the MON. Therefore, this emission process group will only
  appear in the whole facility modeling file, and not in the source
  category modeling file.

    The RTR emissions dataset was refined following an extensive 
quality assurance check of source locations, emission release point 
parameters, and annual emission estimates. The EPA reviewed the 
locations of emission release points at each facility and revised each 
record as needed to ensure that all release points were located within 
the fenceline of the facility. If an emission release point was located 
outside of the facility fenceline or on an obviously incorrect location 
within the fenceline (e.g., parking lot, lake, etc.) then the emission 
release point was re-located to either the true location of the 
equipment, if known, or the approximate center of the facility.
    The emission release point parameters for stacks in the modeling 
input files include stack height, exit gas temperature, stack diameter, 
exit gas velocity, and exit gas flow rate. If emission release point 
parameters were outside of typical quality assurance range checks or 
missing, then the air permit was used to try and determine the 
permitted value. If this information could not be found within the air 
permit, then a surrogate value was assigned based on either the NAICS 
code, the regulatory code, or the SCC. In some cases, missing emission 
release point parameters were calculated using other parameters within 
the modeling input file. For example, missing exit gas flow rates were 
calculated using reported diameter and velocity.
    Additionally, the EPA compared the emission release point type 
(i.e., fugitive, stack) to the emission unit and process descriptions 
for the modeling file records. In cases where information was 
conflicting (i.e., equipment leaks being modeled as a vertical stack, 
or process vent emissions being modeled as a fugitive area), we updated 
the emission release point type to the appropriate category and 
supplemented the appropriate emission release parameters using either 
permitted values, when available, or defaulted values.
    In some cases, the EPA coordinated with Regional offices, state 
agencies, and/or industry on a specific emission record if it was 
unknown whether the emissions belonged to a MON process and preliminary 
risk analysis indicated that this pollutant might be a risk driver. 
This specific inquiry was done to ensure that only MON emissions were 
included in the source category modeling file. To further improve the 
quality of the modeling file, in September 2017, the EPA provided 
member companies of ACC and ACA with the emissions modeling input 
records. The emissions records were also sent directly to several 
companies. This allowed companies the opportunity to review and revise 
emission values, emission release point parameters, and coordinates, as 
needed. Any changes received between September 2017 and November 2018 
were incorporated into the RTR modeling file. Changes received after 
November 2018 will be considered for incorporation in the final rule. A 
list of responses received from the Regional offices, state agencies, 
and chemical companies can be found in Appendix 1 of the document 
titled 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. This memorandum provides a description of the 
information received, the file name of the response received, and 
details on how the information was used to supplement the modeling 
file. This memorandum also provides records of all changes made to the 
source category and whole facility modeling input files throughout the 
quality assurance and quality control process, and additional details 
on the data and methods used to develop actual emissions estimates for 
the risk modeling, including the EPA's quality assurance review.
2. How did we estimate MACT-allowable emissions?
    The available emissions data in the RTR emissions dataset include 
estimates of the mass of HAP emitted during a specified annual time 
period. These ``actual'' emission levels are often lower than the 
emission levels allowed under the requirements of the current MACT 
standards. The emissions allowed under the MACT standards are referred 
to as the ``MACT-allowable'' emissions. We discussed the consideration 
of both MACT-allowable and actual emissions in the final Coke Oven 
Batteries RTR (70 FR 19998-19999, April 15, 2005) and in the proposed 
and final Hazardous Organic NESHAP RTR (71 FR 34428, June 14, 2006, and 
71 FR 76609, December 21, 2006, respectively). In those actions, we 
noted that assessing the risk at the MACT-allowable level is inherently 
reasonable since that risk reflects the maximum level facilities could 
emit and still comply with national emission standards. We also 
explained that it is reasonable to consider actual emissions, where 
such data are available, in both steps of the risk analysis, in 
accordance with the Benzene NESHAP approach. (54 FR 38044, September 
14, 1989.)
    For this analysis, we have determined that the actual emissions 
data are reasonable estimates of the MACT-allowable emissions levels 
for the Miscellaneous Organic Chemical Manufacturing source category. 
The ability to estimate MACT-allowable emissions from the actual 
emissions dataset is largely dependent on the format of the standard 
for a given emissions source as well as the types of controls employed 
for the source. For further details on the assumptions and 
methodologies used to estimate MACT-allowable emissions, see Appendix 1 
of the document titled 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.
3. How do we conduct dispersion modeling, determine inhalation 
exposures, and estimate individual and population inhalation risk?
    Both long-term and short-term inhalation exposure concentrations 
and health risk from the source category addressed in this proposal 
were estimated using the Human Exposure Model (HEM-3).\7\ The HEM-3 
performs three primary risk assessment activities: (1) Conducting 
dispersion modeling to estimate the concentrations of HAP in ambient 
air, (2) estimating long-term and short-term inhalation exposures to 
individuals residing within 50 kilometers (km) of the modeled sources, 
and (3) estimating individual and population-level inhalation risk 
using the exposure estimates and quantitative dose-response 
information.
---------------------------------------------------------------------------

    \7\ For more information about HEM-3, go to https://www.epa.gov/fera/risk-assessment-and-modeling-human-exposure-model-hem.
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a. Dispersion Modeling
    The air dispersion model AERMOD, used by the HEM-3 model, is one of 
the EPA's preferred models for assessing air pollutant concentrations 
from industrial facilities.\8\ To perform the dispersion modeling and 
to develop the

[[Page 69191]]

preliminary risk estimates, HEM-3 draws on three data libraries. The 
first is a library of meteorological data, which is used for dispersion 
calculations. This library includes 1 year (2016) of hourly surface and 
upper air observations from 824 meteorological stations, selected to 
provide coverage of the United States and Puerto Rico. A second library 
of United States Census Bureau census block \9\ internal point 
locations and populations provides the basis of human exposure 
calculations (U.S. Census, 2010). In addition, for each census block, 
the census library includes the elevation and controlling hill height, 
which are also used in dispersion calculations. A third library of 
pollutant-specific dose-response values is used to estimate health 
risk. These are discussed below.
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    \8\ U.S. EPA. Revision to the Guideline on Air Quality Models: 
Adoption of a Preferred General Purpose (Flat and Complex Terrain) 
Dispersion Model and Other Revisions (70 FR 68218, November 9, 
2005).
    \9\ A census block is the smallest geographic area for which 
census statistics are tabulated.
---------------------------------------------------------------------------

b. Risk From Chronic Exposure to HAP
    In developing the risk assessment for chronic exposures, we use the 
estimated annual average ambient air concentrations of each HAP emitted 
by each source in the source category. The HAP air concentrations at 
each nearby census block centroid located within 50 km of the facility 
are a surrogate for the chronic inhalation exposure concentration for 
all the people who reside in that census block. A distance of 50 km is 
consistent with both the analysis supporting the 1989 Benzene NESHAP 
(54 FR 38044, September 14, 1989) and the limitations of Gaussian 
dispersion models, including AERMOD.
    For each facility, we calculate the MIR as the cancer risk 
associated with a continuous lifetime (24 hours per day, 7 days per 
week, 52 weeks per year, 70 years) exposure to the maximum 
concentration at the centroid of each inhabited census block. We 
calculate individual cancer risk by multiplying the estimated lifetime 
exposure to the ambient concentration of each HAP (in micrograms per 
cubic meter ([mu]g/m\3\)) by its URE. 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, often using 
California EPA (CalEPA) UREs, 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.
    To estimate individual lifetime cancer risks associated with 
exposure to HAP emissions from each facility in the source category, we 
sum the risks for each of the carcinogenic HAP \10\ emitted by the 
modeled facility. We estimate cancer risk at every census block within 
50 km of every facility in the source category. The MIR is the highest 
individual lifetime cancer risk estimated for any of those census 
blocks. In addition to calculating the MIR, we estimate the 
distribution of individual cancer risks for the source category by 
summing the number of individuals within 50 km of the sources whose 
estimated risk falls within a specified risk range. We also estimate 
annual cancer incidence by multiplying the estimated lifetime cancer 
risk at each census block by the number of people residing in that 
block, summing results for all of the census blocks, and then dividing 
this result by a 70-year lifetime.
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    \10\ The EPA's 2005 Guidelines for Carcinogen Risk Assessment 
classifies carcinogens as: ``carcinogenic to humans,'' ``likely to 
be carcinogenic to humans,'' and ``suggestive evidence of 
carcinogenic potential.'' These classifications also coincide with 
the terms ``known carcinogen, probable carcinogen, and possible 
carcinogen,'' respectively, which are the terms advocated in the 
EPA's Guidelines for Carcinogen Risk Assessment, published in 1986 
(51 FR 33992, September 24, 1986). In August 2000, the document, 
Supplemental Guidance for Conducting Health Risk Assessment of 
Chemical Mixtures (EPA/630/R-00/002), was published as a supplement 
to the 1986 document. Copies of both documents can be obtained from 
https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=20533&CFID=70315376&CFTOKEN=71597944. Summing 
the risk of these individual compounds to obtain the cumulative 
cancer risk is an approach that was recommended by the EPA's SAB in 
their 2002 peer review of the EPA's National Air Toxics Assessment 
(NATA) titled NATA--Evaluating the National-scale Air Toxics 
Assessment 1996 Data--an SAB Advisory, available at https://
yosemite.epa.gov/sab/sabproduct.nsf/
214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf.
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    To assess the risk of noncancer health effects from chronic 
exposure to HAP, we calculate either an HQ or a target organ-specific 
hazard index (TOSHI). We calculate an HQ when a single noncancer HAP is 
emitted. Where more than one noncancer HAP is emitted, we sum the HQ 
for each of the HAP that affects a common target organ or target organ 
system to obtain a TOSHI. The HQ is the estimated exposure divided by 
the chronic noncancer dose-response value, which is a value selected 
from one of several sources. The preferred chronic noncancer dose-
response value is the EPA RfC, defined as ``an estimate (with 
uncertainty spanning perhaps an order of magnitude) of a continuous 
inhalation exposure to the human population (including sensitive 
subgroups) that is likely to be without an appreciable risk of 
deleterious effects during a lifetime'' (https://iaspub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&vocabName=IRIS%20Glossary). In cases where an RfC 
from the EPA's IRIS is not available or where the EPA determines that 
using a value other than the RfC is appropriate, the chronic noncancer 
dose-response value can be a value from the following prioritized 
sources, which define their dose-response values similarly to the EPA: 
(1) The Agency for Toxic Substances and Disease Registry (ATSDR) 
Minimum Risk Level (https://www.atsdr.cdc.gov/mrls/index.asp); (2) the 
CalEPA Chronic Reference Exposure Level (REL) (https://oehha.ca.gov/air/crnr/notice-adoption-air-toxics-hot-spots-program-guidance-manual-preparation-health-risk-0); or (3) as noted above, a scientifically 
credible dose-response value that has been developed in a manner 
consistent with the EPA guidelines and has undergone a peer review 
process similar to that used by the EPA. The pollutant-specific dose-
response values used to estimate chronic noncancer health risks are 
available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
c. Risk from Acute Exposure to HAP That May Cause Health Effects Other 
Than Cancer
    For each HAP for which appropriate acute inhalation dose-response 
values are available, the EPA also assesses the potential health risks 
due to acute exposure. For these assessments, the EPA makes 
conservative assumptions about emission rates, meteorology, and 
exposure location. In this proposed rulemaking, as part of our efforts 
to continually improve our methodologies to evaluate the risks that HAP 
emitted from categories of industrial sources pose to human health and 
the

[[Page 69192]]

environment,\11\ we are revising our treatment of meteorological data 
to use reasonable worst-case air dispersion conditions in our acute 
risk screening assessments instead of worst-case air dispersion 
conditions. This revised treatment of meteorological data and the 
supporting rationale are described in more detail in Residual Risk 
Assessment for the Miscellaneous Organic Chemical Manufacturing Source 
Category in Support of the 2019 Risk and Technology Review Proposed 
Rule and in Appendix 5 of the report: Technical Support Document for 
Acute Risk Screening Assessment. We will be applying this revision in 
RTR rulemakings proposed on or after June 3, 2019.
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    \11\ See, e.g., U.S. EPA. Screening Methodologies to Support 
Risk and Technology Reviews (RTR): A Case Study Analysis, Draft 
Report, May 2017. https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
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    To assess the potential acute risk to the maximally exposed 
individual, we use the peak hourly emission rate for each emission 
point,\12\ reasonable worst-case air dispersion conditions (i.e., 99th 
percentile), and the point of highest off-site exposure. Specifically, 
we assume that peak emissions from the source category and reasonable 
worst-case air dispersion conditions co-occur and that a person is 
present at the point of maximum exposure.
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    \12\ In the absence of hourly emission data, we develop 
estimates of maximum hourly emission rates by multiplying the 
average actual annual emissions rates by a factor (either a 
category-specific factor or a default factor of 10) to account for 
variability. This is documented in Residual Risk Assessment for 
Miscellaneous Organic Chemical Manufacturing Source Category in 
Support of the 2019 Risk and Technology Review Proposed Rule and in 
Appendix 5 of the report: Technical Support Document for Acute Risk 
Screening Assessment. Both are available in the docket for this 
rulemaking.
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    To characterize the potential health risks associated with 
estimated acute inhalation exposures to a HAP, we generally use 
multiple acute dose-response values, including acute RELs, acute 
exposure guideline levels (AEGLs), and emergency response planning 
guidelines (ERPG) for 1-hour exposure durations, if available, to 
calculate acute HQs. The acute HQ is calculated by dividing the 
estimated acute exposure concentration by the acute dose-response 
value. For each HAP for which acute dose-response values are available, 
the EPA calculates acute HQs.
    An acute REL is defined as ``the concentration level at or below 
which no adverse health effects are anticipated for a specified 
exposure duration.'' \13\ Acute RELs are based on the most sensitive, 
relevant, adverse health effect reported in the peer-reviewed medical 
and toxicological literature. They are designed to protect the most 
sensitive individuals in the population through the inclusion of 
margins of safety. Because margins of safety are incorporated to 
address data gaps and uncertainties, exceeding the REL does not 
automatically indicate an adverse health impact. AEGLs represent 
threshold exposure limits for the general public and are applicable to 
emergency exposures ranging from 10 minutes to 8 hours.\14\ They are 
guideline levels for ``once-in-a-lifetime, short-term exposures to 
airborne concentrations of acutely toxic, high-priority chemicals.'' 
Id. at 21. The AEGL-1 is specifically defined as ``the airborne 
concentration (expressed as ppm (parts per million) or mg/m\3\ 
(milligrams per cubic meter)) of a substance above which it is 
predicted that the general population, including susceptible 
individuals, could experience notable discomfort, irritation, or 
certain asymptomatic nonsensory effects. However, the effects are not 
disabling and are transient and reversible upon cessation of 
exposure.'' The document also notes that ``Airborne concentrations 
below AEGL-1 represent exposure levels that can produce mild and 
progressively increasing but transient and nondisabling odor, taste, 
and sensory irritation or certain asymptomatic, nonsensory effects.'' 
Id. AEGL-2 are defined as ``the airborne concentration (expressed as 
parts per million or milligrams per cubic meter) of a substance above 
which it is predicted that the general population, including 
susceptible individuals, could experience irreversible or other 
serious, long-lasting adverse health effects or an impaired ability to 
escape.'' Id.
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    \13\ CalEPA issues acute RELs as part of its Air Toxics Hot 
Spots Program, and the 1-hour and 8-hour values are documented in 
Air Toxics Hot Spots Program Risk Assessment Guidelines, Part I, The 
Determination of Acute Reference Exposure Levels for Airborne 
Toxicants, which is available at https://oehha.ca.gov/air/general-info/oehha-acute-8-hour-and-chronic-reference-exposure-level-rel-summary.
    \14\ National Academy of Sciences, 2001. Standing Operating 
Procedures for Developing Acute Exposure Levels for Hazardous 
Chemicals, page 2. Available at https://www.epa.gov/sites/production/files/2015-09/documents/sop_final_standing_operating_procedures_2001.pdf. Note that the 
National Advisory Committee for Acute Exposure Guideline Levels for 
Hazardous Substances ended in October 2011, but the AEGL program 
continues to operate at the EPA and works with the National 
Academies to publish final AEGLs (https://www.epa.gov/aegl).
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    ERPGs are ``developed for emergency planning and are intended as 
health-based guideline concentrations for single exposures to 
chemicals.'' \15\ Id. at 1. The ERPG-1 is defined as ``the maximum 
airborne concentration below which it is believed that nearly all 
individuals could be exposed for up to 1 hour without experiencing 
other than mild transient adverse health effects or without perceiving 
a clearly defined, objectionable odor.'' Id. at 2. Similarly, the ERPG-
2 is defined as ``the maximum airborne concentration below which it is 
believed that nearly all individuals could be exposed for up to one 
hour without experiencing or developing irreversible or other serious 
health effects or symptoms which could impair an individual's ability 
to take protective action.'' Id. at 1.
---------------------------------------------------------------------------

    \15\ ERPGS Procedures and Responsibilities. March 2014. American 
Industrial Hygiene Association. Available at: https://www.aiha.org/get-involved/AIHAGuidelineFoundation/EmergencyResponsePlanningGuidelines/Documents/ERPG%20Committee%20Standard%20Operating%20Procedures%20%20-%20March%202014%20Revision%20%28Updated%2010-2-2014%29.pdf.
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    An acute REL for 1-hour exposure durations is typically lower than 
its corresponding AEGL-1 and ERPG-1. Even though their definitions are 
slightly different, AEGL-1s are often the same as the corresponding 
ERPG-1s, and AEGL-2s are often equal to ERPG-2s. The maximum HQs from 
our acute inhalation screening risk assessment typically result when we 
use the acute REL for a HAP. In cases where the maximum acute HQ 
exceeds 1, we also report the HQ based on the next highest acute dose-
response value (usually the AEGL-1 and/or the ERPG-1).
    For the acute inhalation risk assessment of the Miscellaneous 
Organic Chemical Manufacturing source category, we used process level-
specific acute emissions multipliers, ranging from a factor of 2 to 10. 
In general, hourly emissions estimates were based on peak-to-mean 
ratios for 37 emission process groups, with emissions from transfer 
racks and other emission process groups where sufficient information 
did not exist to adequately assess peak hourly emissions (e.g., flares 
controlling various unknown emissions sources) having the highest 
hourly peak emissions at a factor of 10 times the annual average. A 
further discussion of why these factors were selected can be found in 
Appendix 1 of the document titled 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.
    In our acute inhalation screening risk assessment, acute impacts 
are deemed negligible for HAP for which acute HQs are less than or 
equal to 1, and no further analysis is performed for these

[[Page 69193]]

HAP. In cases where an acute HQ from the screening step is greater than 
1, we assess the site-specific data to ensure that the acute HQ is at 
an off-site location. For this source category, the data refinements 
employed consisted of ensuring the locations where the maximum HQ 
occurred were off facility property and where the public could 
potentially be exposed. These refinements are discussed more fully in 
the 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 source category.
4. How do we conduct the multipathway exposure and risk screening 
assessment?
    The EPA conducts a tiered screening assessment examining the 
potential for significant human health risks due to exposures via 
routes other than inhalation (i.e., ingestion). We first determine 
whether any sources in the source category emit any HAP known to be 
persistent and bioaccumulative in the environment, as identified in the 
EPA's Air Toxics Risk Assessment Library (see Volume 1, Appendix D, at 
https://www.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library).
    For the Miscellaneous Organic Chemical Manufacturing source 
category, we identified PB-HAP emissions of polycyclic organic matter 
(POM) (of which polycyclic aromatic hydrocarbons is a subset), lead 
compounds, mercury compounds, cadmium compounds, and arsenic compounds, 
so we proceeded to the next step of the evaluation. Except for lead, 
the human health risk screening assessment for PB-HAP consists of three 
progressive tiers. In a Tier 1 screening assessment, we determine 
whether the magnitude of the facility-specific emissions of PB-HAP 
warrants further evaluation to characterize human health risk through 
ingestion exposure. To facilitate this step, we evaluate emissions 
against previously developed screening threshold emission rates for 
several PB-HAP that are based on a hypothetical upper-end screening 
exposure scenario developed for use in conjunction with the EPA's Total 
Risk Integrated Methodology.Fate, Transport, and Ecological Exposure 
(TRIM.FaTE) model. The PB-HAP with screening threshold emission rates 
are arsenic compounds, cadmium compounds, chlorinated dibenzodioxins 
and furans, mercury compounds, and POM. Based on the EPA estimates of 
toxicity and bioaccumulation potential, these pollutants represent a 
conservative list for inclusion in multipathway risk assessments for 
RTR rules. (See Volume 1, Appendix D at https://www.epa.gov/sites/production/files/2013-08/documents/volume_1_reflibrary.pdf). In this 
assessment, we compare the facility-specific emission rates of these 
PB-HAP to the screening threshold emission rates for each PB-HAP to 
assess the potential for significant human health risks via the 
ingestion pathway. We call this application of the TRIM.FaTE model the 
Tier 1 screening assessment. The ratio of a facility's actual emission 
rate to the Tier 1 screening threshold emission rate is a ``screening 
value'' (SV).
    We derive the Tier 1 screening threshold emission rates for these 
PB-HAP (other than lead compounds) to correspond to a maximum excess 
lifetime cancer risk of 1-in-1 million (i.e., for arsenic compounds, 
polychlorinated dibenzodioxins and furans and POM) or, for HAP that 
cause noncancer health effects (i.e., cadmium compounds and mercury 
compounds), a maximum HQ of 1. If the emission rate of any one PB-HAP 
or combination of carcinogenic PB-HAP in the Tier 1 screening 
assessment exceeds the Tier 1 screening threshold emission rate for any 
facility (i.e., the SV is greater than 1), we conduct a second 
screening assessment, which we call the Tier 2 screening assessment. 
The Tier 2 screening assessment separates the Tier 1 combined fisher 
and farmer exposure scenario into fisher, farmer, and gardener 
scenarios that retain upper-bound ingestion rates.
    In the Tier 2 screening assessment, the location of each facility 
that exceeds a Tier 1 screening threshold emission rate is used to 
refine the assumptions associated with the Tier 1 fisher and farmer 
exposure scenarios at that facility. A key assumption in the Tier 1 
screening assessment is that a lake and/or farm is located near the 
facility. As part of the Tier 2 screening assessment, we use a U.S. 
Geological Survey (USGS) database to identify actual waterbodies within 
50 km of each facility and assume the fisher only consumes fish from 
lakes within that 50 km zone. We also examine the differences between 
local meteorology near the facility and the meteorology used in the 
Tier 1 screening assessment. We then adjust the previously-developed 
Tier 1 screening threshold emission rates for each PB-HAP for each 
facility based on an understanding of how exposure concentrations 
estimated for the screening scenario change with the use of local 
meteorology and USGS lakes database.
    In the Tier 2 farmer scenario, we maintain an assumption that the 
farm is located within 0.5 km of the facility and that the farmer 
consumes meat, eggs, dairy, vegetables, and fruit produced near the 
facility. We may further refine the Tier 2 screening analysis by 
assessing a gardener scenario to characterize a range of exposures, 
with the gardener scenario being more plausible in RTR evaluations. 
Under the gardener scenario, we assume the gardener consumes home-
produced eggs, vegetables, and fruit products at the same ingestion 
rate as the farmer. The Tier 2 screen continues to rely on the high-end 
food intake assumptions that were applied in Tier 1 for local fish 
(adult female angler at 99th percentile fish consumption \16\) and 
locally grown or raised foods (90th percentile consumption of locally 
grown or raised foods for the farmer and gardener scenarios \17\). If 
PB-HAP emission rates do not result in a Tier 2 SV greater than 1, we 
consider those PB-HAP emissions to pose risks below a level of concern. 
If the PB-HAP emission rates for a facility exceed the Tier 2 screening 
threshold emission rates, we may conduct a Tier 3 screening assessment.
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    \16\ Burger, J. 2002. Daily consumption of wild fish and game: 
Exposures of high end recreationists. International Journal of 
Environmental Health Research 12:343-354.
    \17\ U.S. EPA. Exposure Factors Handbook 2011 Edition (Final). 
U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/
052F, 2011.
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    There are several analyses that can be included in a Tier 3 
screening assessment, depending upon the extent of refinement 
warranted, including validating that the lakes are fishable, locating 
residential/garden locations for urban and/or rural settings, 
considering plume-rise to estimate emissions lost above the mixing 
layer, and considering hourly effects of meteorology and plume rise on 
chemical fate and transport (a time-series analysis). If necessary, the 
EPA may further refine the screening assessment through a site-specific 
assessment.
    In evaluating the potential multipathway risk from emissions of 
lead compounds, rather than developing a screening threshold emission 
rate, we compare maximum estimated chronic inhalation exposure 
concentrations to the level of the current National Ambient Air Quality 
Standard (NAAQS) for lead.\18\ Values below the level of the

[[Page 69194]]

primary (health-based) lead NAAQS are considered to have a low 
potential for multipathway risk.
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    \18\ In doing so, the EPA notes that the legal standard for a 
primary NAAQS--that a standard is requisite to protect public health 
and provide an adequate margin of safety (CAA section 109(b))--
differs from the CAA section 112(f) standard (requiring, among other 
things, that the standard provide an ``ample margin of safety to 
protect public health''). However, the primary lead NAAQS is a 
reasonable measure of determining risk acceptability (i.e., the 
first step of the Benzene NESHAP analysis) since it is designed to 
protect the most susceptible group in the human population--
children, including children living near major lead emitting 
sources. 73 FR 67002/3; 73 FR 67000/3; 73 FR 67005/1. In addition, 
applying the level of the primary lead NAAQS at the risk 
acceptability step is conservative, since that primary lead NAAQS 
reflects an adequate margin of safety.
---------------------------------------------------------------------------

    For further information on the multipathway assessment approach, 
see the 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 action.
5. How do we assess risks considering emissions control options?
    In addition to assessing baseline inhalation risks and screening 
for potential multipathway risks, we also estimate risks considering 
the potential emission reductions that would be achieved by the control 
options under consideration. In these cases, the expected emission 
reductions are applied to the specific HAP and emission points in the 
RTR emissions dataset to develop corresponding estimates of risk and 
incremental risk reductions.
6. How do we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect, Environmental HAP, and Ecological 
Benchmarks
    The EPA conducts a screening assessment to examine the potential 
for an adverse environmental effect as required under section 
112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines ``adverse 
environmental effect'' as ``any significant and widespread adverse 
effect, which may reasonably be anticipated, to wildlife, aquatic life, 
or other natural resources, including adverse impacts on populations of 
endangered or threatened species or significant degradation of 
environmental quality over broad areas.''
    The EPA focuses on eight HAP, which are referred to as 
``environmental HAP,'' in its screening assessment: Six PB-HAP and two 
acid gases. The PB-HAP included in the screening assessment are arsenic 
compounds, cadmium compounds, dioxins/furans, POM, mercury (both 
inorganic mercury and methyl mercury), and lead compounds. The acid 
gases included in the screening assessment are hydrochloric acid (HCl) 
and hydrogen fluoride (HF).
    HAP that persist and bioaccumulate are of particular environmental 
concern because they accumulate in the soil, sediment, and water. The 
acid gases, HCl and HF, are included due to their well-documented 
potential to cause direct damage to terrestrial plants. In the 
environmental risk screening assessment, we evaluate the following four 
exposure media: Terrestrial soils, surface water bodies (includes 
water-column and benthic sediments), fish consumed by wildlife, and 
air. Within these four exposure media, we evaluate nine ecological 
assessment endpoints, which are defined by the ecological entity and 
its attributes. For PB-HAP (other than lead), both community-level and 
population-level endpoints are included. For acid gases, the ecological 
assessment evaluated is terrestrial plant communities.
    An ecological benchmark represents a concentration of HAP that has 
been linked to a particular environmental effect level. For each 
environmental HAP, we identified the available ecological benchmarks 
for each assessment endpoint. We identified, where possible, ecological 
benchmarks at the following effect levels: Probable effect levels, 
lowest-observed-adverse-effect level, and no-observed-adverse-effect 
level. In cases where multiple effect levels were available for a 
particular PB-HAP and assessment endpoint, we use all of the available 
effect levels to help us to determine whether ecological risks exist 
and, if so, whether the risks could be considered significant and 
widespread.
    For further information on how the environmental risk screening 
assessment was conducted, including a discussion of the risk metrics 
used, how the environmental HAP were identified, and how the ecological 
benchmarks were selected, see Appendix 9 of the 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 action.
b. Environmental Risk Screening Methodology
    For the environmental risk screening assessment, the EPA first 
determined whether any facilities in the Miscellaneous Organic Chemical 
Manufacturing source category emitted any of the environmental HAP. For 
the Miscellaneous Organic Chemical Manufacturing source category, we 
identified emissions of POM, lead compounds, mercury compounds, cadmium 
compounds, arsenic compounds, HCl, and HF. Because one or more of the 
environmental HAP evaluated are emitted by at least one facility in the 
source category, we proceeded to the second step of the evaluation.
c. PB-HAP Methodology
    The environmental screening assessment includes six PB-HAP, arsenic 
compounds, cadmium compounds, dioxins/furans, POM, mercury (both 
inorganic mercury and methyl mercury), and lead compounds. With the 
exception of lead, the environmental risk screening assessment for PB-
HAP consists of three tiers. The first tier of the environmental risk 
screening assessment uses the same health-protective conceptual model 
that is used for the Tier 1 human health screening assessment. 
TRIM.FaTE model simulations were used to back-calculate Tier 1 
screening threshold emission rates. The screening threshold emission 
rates represent the emission rate in tons of pollutant per year that 
results in media concentrations at the facility that equal the relevant 
ecological benchmark. To assess emissions from each facility in the 
category, the reported emission rate for each PB-HAP was compared to 
the Tier 1 screening threshold emission rate for that PB-HAP for each 
assessment endpoint and effect level. If emissions from a facility do 
not exceed the Tier 1 screening threshold emission rate, the facility 
``passes'' the screening assessment, and, therefore, is not evaluated 
further under the screening approach. If emissions from a facility 
exceed the Tier 1 screening threshold emission rate, we evaluate the 
facility further in Tier 2.
    In Tier 2 of the environmental screening assessment, the screening 
threshold emission rates are adjusted to account for local meteorology 
and the actual location of lakes in the vicinity of facilities that did 
not pass the Tier 1 screening assessment. For soils, we evaluate the 
average soil concentration for all soil parcels within a 7.5-km radius 
for each facility and PB-HAP. For the water, sediment, and fish tissue 
concentrations, the highest value for each facility for each pollutant 
is used. If emission concentrations from a facility do not exceed the 
Tier 2 screening threshold emission rate, the facility ``passes'' the 
screening assessment and typically is not evaluated further. If 
emissions from a

[[Page 69195]]

facility exceed the Tier 2 screening threshold emission rate, we 
evaluate the facility further in Tier 3.
    As in the multipathway human health risk assessment, in Tier 3 of 
the environmental screening assessment, we examine the suitability of 
the lakes around the facilities to support life and remove those that 
are not suitable (e.g., lakes that have been filled in or are 
industrial ponds), adjust emissions for plume-rise, and conduct hour-
by-hour time-series assessments. If these Tier 3 adjustments to the 
screening threshold emission rates still indicate the potential for an 
adverse environmental effect (i.e., facility emission rate exceeds the 
screening threshold emission rate), we may elect to conduct a more 
refined assessment using more site-specific information. If, after 
additional refinement, the facility emission rate still exceeds the 
screening threshold emission rate, the facility may have the potential 
to cause an adverse environmental effect.
    To evaluate the potential for an adverse environmental effect from 
lead, we compared the average modeled air concentrations (from HEM-3) 
of lead around each facility in the source category to the level of the 
secondary NAAQS for lead. The secondary lead NAAQS is a reasonable 
means of evaluating environmental risk because it is set to provide 
substantial protection against adverse welfare effects which can 
include ``effects on soils, water, crops, vegetation, man-made 
materials, animals, wildlife, weather, visibility and climate, damage 
to and deterioration of property, and hazards to transportation, as 
well as effects on economic values and on personal comfort and well-
being.''
d. Acid Gas Environmental Risk Methodology
    The environmental screening assessment for acid gases evaluates the 
potential phytotoxicity and reduced productivity of plants due to 
chronic exposure to HF and HCl. The environmental risk screening 
methodology for acid gases is a single-tier screening assessment that 
compares modeled ambient air concentrations (from AERMOD) to the 
ecological benchmarks for each acid gas. To identify a potential 
adverse environmental effect (as defined in section 112(a)(7) of the 
CAA) from emissions of HF and HCl, we evaluate the following metrics: 
The size of the modeled area around each facility that exceeds the 
ecological benchmark for each acid gas, in acres and km\2\; the 
percentage of the modeled area around each facility that exceeds the 
ecological benchmark for each acid gas; and the area-weighted average 
SV around each facility (calculated by dividing the area-weighted 
average concentration over the 50-km modeling domain by the ecological 
benchmark for each acid gas). For further information on the 
environmental screening assessment approach, see Appendix 9 of the 
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 action.
7. How do we conduct facility-wide assessments?
    To put the source category risks in context, we typically examine 
the risks from the entire ``facility,'' where the facility includes all 
HAP-emitting operations within a contiguous area and under common 
control. In other words, we examine the HAP emissions not only from the 
source category emission points of interest, but also emissions of HAP 
from all other emission sources at the facility for which we have data. 
For this source category, we conducted the facility-wide assessment 
using a dataset compiled from the 2014 NEI. The source category records 
of that NEI dataset were flagged within the dataset, as described in 
section II.C of this preamble: What data collection activities were 
conducted to support this action? Quality assurance and quality control 
was performed on the whole facility dataset, which included the flagged 
source category records. The facility-wide file was then used to 
analyze risks due to the inhalation of HAP that are emitted ``facility-
wide'' for the populations residing within 50 km of each facility, 
consistent with the methods used for the source category analysis 
described above. For these facility-wide risk analyses, the modeled 
source category risks were compared to the facility-wide risks to 
determine the portion of the facility-wide risks that could be 
attributed to the source category addressed in this proposal. We also 
specifically examined the facility that was associated with the highest 
estimate of risk and determined the percentage of that risk 
attributable to the source category of interest. The Residual Risk 
Assessment for the Miscellaneous Organic Chemical Manufacturing Source 
Category in Support of the 2019 Risk and Technology Review Proposed 
Rule, available through the docket for this action, provides the 
methodology and results of the facility-wide analyses, including all 
facility-wide risks and the percentage of source category contribution 
to facility-wide risks.
8. How do we consider uncertainties in risk assessment?
    Uncertainty and the potential for bias are inherent in all risk 
assessments, including those performed for this proposal. Although 
uncertainty exists, we believe that our approach, which used 
conservative tools and assumptions, ensures that our decisions are 
health and environmentally protective. A brief discussion of the 
uncertainties in the RTR emissions dataset, dispersion modeling, 
inhalation exposure estimates, and dose-response relationships follows 
below. Also included are those uncertainties specific to our acute 
screening assessments, multipathway screening assessments, and our 
environmental risk screening assessments. A more thorough discussion of 
these uncertainties is included in the 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 action. If a multipathway site-
specific assessment was performed for this source category, a full 
discussion of the uncertainties associated with that assessment can be 
found in Appendix 11 of that document, Site-Specific Human Health 
Multipathway Residual Risk Assessment Report.
a. Uncertainties in the RTR Emissions Dataset
    Although the development of the RTR emissions dataset involved 
quality assurance/quality control processes, the accuracy of emissions 
values will vary depending on the source of the data, the degree to 
which data are incomplete or missing, the degree to which assumptions 
made to complete the datasets are accurate, errors in emission 
estimates, and other factors. The emission estimates considered in this 
analysis generally are annual totals for certain years, and they do not 
reflect short-term fluctuations during the course of a year or 
variations from year to year. The estimates of peak hourly emission 
rates for the acute effects screening assessment were based on an 
emission adjustment factor applied to the average annual hourly 
emission rates, which are intended to account for emission fluctuations 
due to normal facility operations.
b. Uncertainties in Dispersion Modeling
    We recognize there is uncertainty in ambient concentration 
estimates associated with any model, including

[[Page 69196]]

the EPA's recommended regulatory dispersion model, AERMOD. In using a 
model to estimate ambient pollutant concentrations, the user chooses 
certain options to apply. For RTR assessments, we select some model 
options that have the potential to overestimate ambient air 
concentrations (e.g., not including plume depletion or pollutant 
transformation). We select other model options that have the potential 
to underestimate ambient impacts (e.g., not including building 
downwash). Other options that we select have the potential to either 
under- or overestimate ambient levels (e.g., meteorology and receptor 
locations). On balance, considering the directional nature of the 
uncertainties commonly present in ambient concentrations estimated by 
dispersion models, the approach we apply in the RTR assessments should 
yield unbiased estimates of ambient HAP concentrations. We also note 
that the selection of meteorology dataset location could have an impact 
on the risk estimates. As we continue to update and expand our library 
of meteorological station data used in our risk assessments, we expect 
to reduce this variability.
c. Uncertainties in Inhalation Exposure Assessment
    Although every effort is made to identify all of the relevant 
facilities and emission points, as well as to develop accurate 
estimates of the annual emission rates for all relevant HAP, the 
uncertainties in our emission inventory likely dominate the 
uncertainties in the exposure assessment. Some uncertainties in our 
exposure assessment include human mobility, using the centroid of each 
census block, assuming lifetime exposure, and assuming only outdoor 
exposures. For most of these factors, there is neither an under nor 
overestimate when looking at the maximum individual risk or the 
incidence, but the shape of the distribution of risks may be affected. 
With respect to outdoor exposures, actual exposures may not be as high 
if people spend time indoors, especially for very reactive pollutants 
or larger particles. For all factors, we reduce uncertainty when 
possible. For example, with respect to census-block centroids, we 
analyze large blocks using aerial imagery and adjust locations of the 
block centroids to better represent the population in the blocks. We 
also add additional receptor locations where the population of a block 
is not well represented by a single location.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and noncancer effects from both chronic and acute 
exposures. Some uncertainties are generally expressed quantitatively, 
and others are generally expressed in qualitative terms. We note, as a 
preface to this discussion, a point on dose-response uncertainty that 
is stated in the EPA's 2005 Guidelines for Carcinogen Risk Assessment; 
namely, that ``the primary goal of EPA actions is protection of human 
health; accordingly, as an Agency policy, risk assessment procedures, 
including default options that are used in the absence of scientific 
data to the contrary, should be health protective'' (the EPA's 2005 
Guidelines for Carcinogen Risk Assessment, page 1-7). This is the 
approach followed here as summarized in the next paragraphs.
    Cancer UREs used in our risk assessments are those that have been 
developed to generally provide an upper bound estimate of risk.\19\ 
That is, they represent a ``plausible upper limit to the true value of 
a quantity'' (although this is usually not a true statistical 
confidence limit). In some circumstances, the true risk could be as low 
as zero; however, in other circumstances the risk could be greater.\20\ 
Chronic noncancer RfC and reference dose (RfD) values represent chronic 
exposure levels that are intended to be health-protective levels. To 
derive dose-response values that are intended to be ``without 
appreciable risk,'' the methodology relies upon an uncertainty factor 
(UF) approach,\21\ which considers uncertainty, variability, and gaps 
in the available data. The UFs are applied to derive dose-response 
values that are intended to protect against appreciable risk of 
deleterious effects.
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    \19\ IRIS glossary (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
    \20\ An exception to this is the URE for benzene, which is 
considered to cover a range of values, each end of which is 
considered to be equally plausible, and which is based on maximum 
likelihood estimates.
    \21\ See A Review of the Reference Dose and Reference 
Concentration Processes, U.S. EPA, December 2002, and Methods for 
Derivation of Inhalation Reference Concentrations and Application of 
Inhalation Dosimetry, U.S. EPA, 1994.
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    Many of the UFs used to account for variability and uncertainty in 
the development of acute dose-response values are quite similar to 
those developed for chronic durations. Additional adjustments are often 
applied to account for uncertainty in extrapolation from observations 
at one exposure duration (e.g., 4 hours) to derive an acute dose-
response value at another exposure duration (e.g., 1 hour). Not all 
acute dose-response values are developed for the same purpose, and care 
must be taken when interpreting the results of an acute assessment of 
human health effects relative to the dose-response value or values 
being exceeded. Where relevant to the estimated exposures, the lack of 
acute dose-response values at different levels of severity should be 
factored into the risk characterization as potential uncertainties.
    Uncertainty also exists in the selection of ecological benchmarks 
for the environmental risk screening assessment. We established a 
hierarchy of preferred benchmark sources to allow selection of 
benchmarks for each environmental HAP at each ecological assessment 
endpoint. We searched for benchmarks for three effect levels (i.e., no-
effects level, threshold-effect level, and probable effect level), but 
not all combinations of ecological assessment/environmental HAP had 
benchmarks for all three effect levels. Where multiple effect levels 
were available for a particular HAP and assessment endpoint, we used 
all of the available effect levels to help us determine whether risk 
exists and whether the risk could be considered significant and 
widespread.
    Although we make every effort to identify appropriate human health 
effect dose-response values for all pollutants emitted by the sources 
in this risk assessment, some HAP emitted by this source category are 
lacking dose-response assessments. Accordingly, these pollutants cannot 
be included in the quantitative risk assessment, which could result in 
quantitative estimates understating HAP risk. To help to alleviate this 
potential underestimate, where we conclude similarity with a HAP for 
which a dose-response value is available, we use that value as a 
surrogate for the assessment of the HAP for which no value is 
available. To the extent use of surrogates indicates appreciable risk, 
we may identify a need to increase priority for an IRIS assessment for 
that substance. We additionally note that, generally speaking, HAP of 
greatest concern due to environmental exposures and hazard are those 
for which dose-response assessments have been performed, reducing the 
likelihood of understating risk. Further, HAP not included in the 
quantitative assessment are assessed

[[Page 69197]]

qualitatively and considered in the risk characterization that informs 
the risk management decisions, including consideration of HAP 
reductions achieved by various control options.
    For a group of compounds that are unspeciated (e.g., glycol 
ethers), we conservatively use the most protective dose-response value 
of an individual compound in that group to estimate risk. Similarly, 
for an individual compound in a group (e.g., ethylene glycol diethyl 
ether) that does not have a specified dose-response value, we also 
apply the most protective dose-response value from the other compounds 
in the group to estimate risk.
e. Uncertainties in Acute Inhalation Screening Assessments
    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that the EPA 
conducts as part of the risk review under section 112 of the CAA. The 
accuracy of an acute inhalation exposure assessment depends on the 
simultaneous occurrence of independent factors that may vary greatly, 
such as hourly emission rates, meteorology, and the presence of a 
person. In the acute screening assessment that we conduct under the RTR 
program, we assume that peak emissions from the source category and 
reasonable worst-case air dispersion conditions (i.e., 99th percentile) 
co-occur. These two events are unlikely to occur at the same time, 
making these assumptions conservative. We then include the additional 
assumption that a person is located at this point at the same time. 
Together, these assumptions represent a reasonable worst-case exposure 
scenario. In most cases, it is unlikely that a person would be located 
at the point of maximum exposure during the time when peak emissions 
and reasonable worst-case air dispersion conditions occur 
simultaneously.
f. Uncertainties in the Multipathway and Environmental Risk Screening 
Assessments
    For each source category, we generally rely on site-specific levels 
of PB-HAP or environmental HAP emissions to determine whether a refined 
assessment of the impacts from multipathway exposures is necessary or 
whether it is necessary to perform an environmental screening 
assessment. This determination is based on the results of a three-
tiered screening assessment that relies on the outputs from models--
TRIM.FaTE and AERMOD--that estimate environmental pollutant 
concentrations and human exposures for five PB-HAP (dioxins, POM, 
mercury, cadmium, and arsenic) and two acid gases (HF and HCl). For 
lead, we use AERMOD to determine ambient air concentrations, which are 
then compared to the secondary NAAQS standard for lead. Two important 
types of uncertainty associated with the use of these models in RTR 
risk assessments and inherent to any assessment that relies on 
environmental modeling are model uncertainty and input uncertainty.\22\
---------------------------------------------------------------------------

    \22\ In the context of this discussion, the term ``uncertainty'' 
as it pertains to exposure and risk encompasses both variability in 
the range of expected inputs and screening results due to existing 
spatial, temporal, and other factors, as well as uncertainty in 
being able to accurately estimate the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the model adequately represents 
the actual processes (e.g., movement and accumulation) that might occur 
in the environment. For example, does the model adequately describe the 
movement of a pollutant through the soil? This type of uncertainty is 
difficult to quantify. However, based on feedback received from 
previous EPA SAB reviews and other reviews, we are confident that the 
models used in the screening assessments are appropriate and state-of-
the-art for the multipathway and environmental screening risk 
assessments conducted in support of RTR.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
1 of the multipathway and environmental screening assessments, we 
configured the models to avoid underestimating exposure and risk. This 
was accomplished by selecting upper-end values from nationally 
representative datasets for the more influential parameters in the 
environmental model, including selection and spatial configuration of 
the area of interest, lake location and size, meteorology, surface 
water, soil characteristics, and structure of the aquatic food web. We 
also assume an ingestion exposure scenario and values for human 
exposure factors that represent reasonable maximum exposures.
    In Tier 2 of the multipathway and environmental screening 
assessments, we refine the model inputs to account for meteorological 
patterns in the vicinity of the facility versus using upper-end 
national values, and we identify the actual location of lakes near the 
facility rather than the default lake location that we apply in Tier 1. 
By refining the screening approach in Tier 2 to account for local 
geographical and meteorological data, we decrease the likelihood that 
concentrations in environmental media are overestimated, thereby 
increasing the usefulness of the screening assessment. In Tier 3 of the 
screening assessments, we refine the model inputs again to account for 
hour-by-hour plume rise and the height of the mixing layer. We can also 
use those hour-by-hour meteorological data in a TRIM.FaTE run using the 
screening configuration corresponding to the lake location. These 
refinements produce a more accurate estimate of chemical concentrations 
in the media of interest, thereby reducing the uncertainty with those 
estimates. The assumptions and the associated uncertainties regarding 
the selected ingestion exposure scenario are the same for all three 
tiers.
    For the environmental screening assessment for acid gases, we 
employ a single-tiered approach. We use the modeled air concentrations 
and compare those with ecological benchmarks.
    For all tiers of the multipathway and environmental screening 
assessments, our approach to addressing model input uncertainty is 
generally cautious. We choose model inputs from the upper end of the 
range of possible values for the influential parameters used in the 
models, and we assume that the exposed individual exhibits ingestion 
behavior that would lead to a high total exposure. This approach 
reduces the likelihood of not identifying high risks for adverse 
impacts.
    Despite the uncertainties, when individual pollutants or facilities 
do not exceed screening threshold emission rates (i.e., screen out), we 
are confident that the potential for adverse multipathway impacts on 
human health is very low. On the other hand, when individual pollutants 
or facilities do exceed screening threshold emission rates, it does not 
mean that impacts are significant, only that we cannot rule out that 
possibility and that a refined assessment for the site might be 
necessary to obtain a more accurate risk characterization for the 
source category.
    The EPA evaluates the following HAP in the multipathway and/or 
environmental risk screening assessments, where applicable: Arsenic, 
cadmium, dioxins/furans, lead, mercury (both inorganic and methyl 
mercury), POM, HCl, and HF. These HAP represent pollutants that can 
cause adverse impacts either through direct exposure to HAP in the air 
or through exposure to HAP that are deposited from the air onto soils 
and surface waters and then through the environment into the food web. 
These HAP represent those HAP for which we can conduct a meaningful 
multipathway

[[Page 69198]]

or environmental screening risk assessment. For other HAP not included 
in our screening assessments, the model has not been parameterized such 
that it can be used for that purpose. In some cases, depending on the 
HAP, we may not have appropriate multipathway models that allow us to 
predict the concentration of that pollutant. The EPA acknowledges that 
other HAP beyond these that we are evaluating may have the potential to 
cause adverse effects and, therefore, the EPA may evaluate other 
relevant HAP in the future, as modeling science and resources allow.

IV. Analytical Results and Proposed Decisions

A. What actions are we taking in addition to those identified in the 
risk and technology review?

    In addition to the proposed actions on the risk review and 
technology review discussed further in this section, we are proposing 
the following: (1) Adding 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, and (2) consistent with Sierra Club v. 
EPA, 551 F.3d 1019 (D.C. Cir. 2008), ensuring that CAA section 112 
standards apply continuously by proposing work practice standards for 
periods of SSM for certain vent streams (i.e., PRD releases and 
maintenance vents), and proposing clarifications for vent control 
bypasses for certain vent streams (i.e., closed vent systems containing 
bypass lines, and flares connected to fuel gas systems). The results 
and proposed decisions based on the analyses performed pursuant to CAA 
section 112(d)(2) and (3) are presented below.
1. Flares
    The EPA is proposing under CAA section 112(d)(2) and (3) to amend 
the operating and monitoring requirements for a subset of flares used 
as APCDs in the Miscellaneous Organic Chemical Manufacturing source 
category because we have determined that the current requirements for 
flares in this subset are not adequate to ensure the level of 
destruction efficiency needed to conform with the MACT standards in the 
MON. This subset includes flares that either (1) control ethylene oxide 
emissions, (2) control emissions from processes that produce olefins, 
or (3) control emissions from processes that produce polyolefins. 
Flares falling into one of these categories are referred to as the 
flare ``subset'' in this preamble, and for clarification, it is our 
intention that, as part of this proposal, flares controlling propane 
dehydrogenation (PDH) processes be included in this flare subset since 
the PDH process produces olefins such as propylene. The EPA is also 
proposing that, for flares outside of this subset, an owner or operator 
may choose to comply with the updated standards in lieu of complying 
with the current flare standards. Therefore, all proposed flare 
standards in section IV.A.1 of this preamble are intended to apply to 
only the specified flare subset and to flares at MON facilities where 
the owner or operator has chosen to opt in to the proposed standards. 
Flares outside of this subset, or at MON facilities where the owner or 
operator has chosen not to opt in to the proposed standards, will be 
subject to the current provisions for flares in the MON standard.
    The specified flare subset was selected on the basis that the 
current requirements for flares may be inadequate to ensure the level 
of destruction efficiency needed to conform with the MACT standards in 
the MON. Flares are commonly used within the Miscellaneous Organic 
Chemical Manufacturing source category. The requirements applicable to 
flares, which are used to control emissions from various emission 
sources in the Miscellaneous Organic Chemical Manufacturing source 
category (e.g., process vents, storage tanks, transfer racks, equipment 
leaks, wastewater streams), are set forth in the General Provisions to 
40 CFR part 63 and are cross-referenced in 40 CFR part 63, subpart G 
(for wastewater), and 40 CFR part 63, subpart SS (for process vents, 
storage tanks, transfer racks, and equipment leaks). In general, flares 
used as APCDs are expected to achieve 98-percent HAP destruction 
efficiencies when designed and operated according to the requirements 
in the General Provisions. Studies on flare performance,\23\ however, 
indicate that these General Provision requirements are inadequate to 
ensure proper performance of flares at refineries and other 
petrochemical facilities (including chemical manufacturing facilities), 
particularly when either assist steam or assist air is used. In 
addition, over the last decade, flare minimization efforts at these 
facilities have led to an increasing number of flares operating at well 
below their design capacity, and while these efforts have resulted in 
reduced flaring of gases, situations of over assisting with either 
steam or air have become exacerbated, leading to the degradation of 
flare combustion efficiency. Several flares located at MON facilities 
control vent streams containing olefins. These MON facilities operate 
directly downstream from refineries and other petrochemical plants 
(e.g., ethylene production plants) and, consequently, likely burn 
similar types of waste gas constituents to a refinery or petrochemical 
plant (e.g., olefins and hydrogen). Given that flares at petrochemical 
plants (including facilities that produce olefins) were also included 
in the flare dataset that formed the underlying basis of the new 
standards for refinery flares, we believe that it is appropriate to 
apply the finalized suite of operational and monitoring requirements 
for refinery flares to those flares in the Miscellaneous Organic 
Chemical Manufacturing source category that control emissions from 
processes that produce olefins and/or polyolefins. Additionally, we 
included flares controlling ethylene oxide emissions within this subset 
to ensure that these flares will achieve high combustion efficiency, 
which is necessary as small quantities of ethylene oxide emissions can 
present significant cancer risks to surrounding communities. Additional 
discussion on this proposed control option is presented in section 
IV.C.2 of this preamble, which proposes that process vents and storage 
tanks in ethylene oxide service either use a control device achieving 
99.9-percent emissions reductions, control emissions using a non-flare 
control device that reduces ethylene oxide to less than 1 part per 
million by volume (ppmv) or (for process vents only) less than 5 pounds 
per year for all combined process vents, or control emissions using a 
flare that meets the proposed flare standards presented in this 
section. Therefore, these proposed amendments will ensure that 
continuous compliance with the CAA section 112(d)(2) and (d)(3) 
standards is achieved for MON facilities that use flares that control 
ethylene oxide emissions and/or flares used to control emissions from 
MCPUs that produce olefins and/or polyolefins. We solicit comments and 
data on the application of these standards to the proposed flare 
subset, the option for an owner or operator to choose to opt in to the 
proposed flare standards for flares outside of this subset in lieu of

[[Page 69199]]

complying with the current flare standards, and the need to apply these 
standards more broadly.
---------------------------------------------------------------------------

    \23\ For a list of studies, refer to the technical report titled 
Parameters for Properly Designed and Operated Flares, in Docket ID 
Item No. EPA-HQ-OAR-2010-0682-0191.
---------------------------------------------------------------------------

    The General Provisions of 40 CFR 63.11(b) specify that flares be: 
(1) Steam-assisted, air-assisted, or non-assisted; (2) operated at all 
times when emissions may be vented to them; (3) designed for and 
operated with no visible emissions (except for periods not to exceed a 
total of 5 minutes during any 2 consecutive hours); and (4) operated 
with the presence of a pilot flame at all times. These General 
Provisions also specify both the minimum heat content of gas combusted 
in the flare and maximum exit velocity at the flare tip. The General 
Provisions specify monitoring for the presence of the pilot flame and 
the operation of a flare with no visible emissions. For other operating 
limits, 40 CFR part 63, subpart SS, includes an initial flare 
compliance assessment to demonstrate compliance but specifies no 
monitoring requirements to ensure continuous compliance. We are 
proposing to revise the General Provisions table to 40 CFR part 63, 
subpart FFFF (Table 12), entries for 40 CFR 63.8(a)(4) and 40 CFR 63.11 
such that these provisions do not apply to flares in the specified 
subset, because we are proposing to replace these provisions with new 
standards we are proposing for flares in the specified subset. We are 
also proposing 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 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.
    In 2012, the EPA compiled information and test data collected on 
flares and summarized its preliminary findings on operating parameters 
that affect flare combustion efficiency in a technical report titled 
Parameters for Properly Designed and Operated Flares, in Docket ID Item 
No. EPA-HQ-OAR-2010-0682-0191.\24\ The EPA submitted this report, along 
with a charge statement and a set of charge questions, to an external 
peer review panel.\25\ The panel, consisting of individuals 
representing a variety of backgrounds and perspectives (i.e., industry, 
academia, environmental experts, and industrial flare consultants), 
concurred with the EPA's assessment that the following three primary 
factors affect flare performance: (1) The flow of the vent gas to the 
flare; (2) the amount of assist media (e.g., steam or air) added to the 
flare; and (3) the combustibility of the vent gas/assist media mixture 
in the combustion zone (i.e., the net heating value, lower 
flammability, and/or combustibles concentration) at the flare tip. 
However, in response to peer review comments, the EPA performed a 
validation and usability analysis on all available test data as well as 
a failure analysis on potential parameters discussed in the technical 
report as indicators of flare performance. The peer review comments are 
in the memorandum titled Peer Review of Parameters for Properly 
Designed and Operated Flares, available in Docket ID Item No. EPA-HQ-
OAR-2010-0682-0193, which has been incorporated into the docket for 
this rulemaking. These analyses resulted in a change to the population 
of test data that the EPA used and helped form the basis for the flare 
operating limits promulgated in the 2015 Petroleum Refinery Sector MACT 
final rule at 40 CFR part 63, subpart CC (80 FR 75178).\26\ We are also 
relying on the same analyses and proposing the same operating limits 
for flares in the specified subset used as APCDs in the Miscellaneous 
Organic Chemical Manufacturing source category. The Agency believes, 
given the results from the various data analyses conducted for the 
Petroleum Refinery Sector MACT rule, that the operating limits 
promulgated for flares used in the petroleum refinery sector are also 
appropriate and reasonable for flares in the specified subset, and will 
ensure that flares in the specified subset meet the HAP removal 
efficiency at all times. Therefore, we are proposing at 40 CFR 
63.2450(e)(5) to directly apply the Petroleum Refinery Sector MACT rule 
flare definitions and requirements in 40 CFR part 63, subpart CC, to 
flares in the specified subset in the Miscellaneous Organic Chemical 
Manufacturing source category with certain clarifications and 
exemptions discussed in this section of the preamble, including, but 
not limited to, specifying that several definitions in 40 CFR part 63, 
subpart CC, that apply to petroleum refinery flares also apply to 
flares in the specified subset in the Miscellaneous Organic Chemical 
Manufacturing source category, adding a definition and requirements for 
pressure-assisted multi-point flares, and specifying additional 
requirements when a gas chromatograph or mass spectrometer is used for 
compositional analysis.
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    \24\ See section II.D of this preamble, which addresses the 
incorporation by reference of certain docket files such as this one 
into the docket for this rulemaking.
    \25\ These documents can also be found at https://www.epa.gov/stationary-sources-air-pollution/review-peer-review-parameters-properly-designed-and-operated-flares.
    \26\ See technical memorandum titled Flare Performance Data: 
Summary of Peer Review Comments and Additional Data Analysis for 
Steam-Assisted Flares, in Docket ID Item No. EPA-HQ-OAR-2010-0682-
0200 for a more detailed discussion of the data quality and 
analysis; the technical memorandum titled Petroleum Refinery Sector 
Rule: Operating Limits for Flares, in Docket ID Item No. EPA-HQ-OAR-
2010-0682-0206 for a more detailed discussion of the failure 
analysis and the technical memorandum titled Flare Control Option 
Impacts for Final Refinery Sector Rule, in Docket ID Item No. EPA-
HQ-OAR-2010-0682-0748 for additional analyses on flare performance 
standards based on public comments received on the proposed 
Petroleum Refinery Sector rule.
---------------------------------------------------------------------------

    The remainder of this section of the preamble includes a discussion 
of requirements that we are proposing for flares in the specified 
subset used as APCDs in the Miscellaneous Organic Chemical 
Manufacturing source category, along with impacts and costs associated 
with these proposed revisions. Specifically, this action proposes that 
flares in the specified subset operate pilot flame systems continuously 
and that flares operate with no visible emissions (except for periods 
not to exceed a total of 5 minutes during any 2 consecutive hours) when 
the flare vent gas flow rate is below the smokeless capacity of the 
flare. In addition, this action proposes to consolidate measures 
related to flare tip velocity and proposes new operational and 
monitoring requirements related to the combustion zone gas. Further, in 
keeping with the elimination of the SSM exemption as discussed in 
section IV.E.1 of this preamble, this action proposes a work practice 
standard related to the visible emissions and velocity limits during 
periods when the flare is operated above its smokeless capacity (e.g., 
periods of emergency flaring). Currently, the MACT standards in the MON 
cross-reference the General Provisions at 40 CFR 63.11(b) for the 
operational requirements for flares used as APCD (through reference of 
40 CFR part 63, subparts G and SS). This proposal eliminates cross-
references to the General Provisions and instead specifies all new 
operational and monitoring requirements that are intended to apply to 
flares in the specified subset used as APCDs in the MON standards.
a. Pilot Flames
    The MON references the flare requirements in 40 CFR 63.11(b) 
(through reference of 40 CFR part 63, subpart G, 40 CFR part 63, 
subpart SS, and Table 12 to 40 CFR part 63, subpart FFFF), which 
specify that a flare used as an APCD should operate with a pilot flame 
present at all times. Pilot flames are proven to improve flare flame 
stability, and even short durations of an extinguished pilot could 
cause a

[[Page 69200]]

significant reduction in flare destruction efficiency. In this 
proposal, we are proposing to remove the cross-reference to the General 
Provisions for flares in the specified subset only and instead cross-
reference 40 CFR part 63, subpart CC, to include in the MON the 
existing provision that flares operate with a pilot flame at all times 
and be continuously monitored for a pilot flame using a thermocouple or 
any other equivalent device. We are also proposing to add a continuous 
compliance measure for flares in the specified subset that would 
consider each 15-minute block when there is at least 1 minute where no 
pilot flame is present when regulated material is routed to the flare 
as a deviation from the standard. Refer to 40 CFR 63.2450(e)(5) and 40 
CFR 63.670(b) and (g) for these proposed requirements. See section 
IV.A.1.e of this preamble for our rationale for proposing to use a 15-
minute block averaging period for determining continuous compliance. We 
solicit comment on the proposed revisions for flare pilot flames.
b. Visible Emissions
    The MON references 40 CFR 63.11(b) (through reference of 40 CFR 
part 63, subpart G, 40 CFR part 63, subpart SS, and Table 12 to 40 CFR 
part 63, subpart FFFF), which specifies that a flare used as an APCD 
should operate with visible emissions for no more than 5 minutes in a 
2-hour period. Owners or operators of these flares are required to 
conduct an initial performance demonstration for visible emissions 
using EPA Method 22 of Appendix A-7 to 40 CFR part 60 (``Method 22''). 
We are proposing to remove the cross-reference to the General 
Provisions for flares in the specified subset and instead cross-
reference 40 CFR part 63, subpart CC, to include the limitation on 
visible emissions. We are also proposing to clarify that the initial 2-
hour visible emissions demonstration should be conducted the first time 
regulated materials are routed to the flare.
    With regard to continuous compliance with the visible emissions 
limitation, we are proposing daily visible emissions monitoring for 
flares in the specified subset for whenever regulated material is 
routed to the flare and also visible emissions monitoring for whenever 
visible emissions are observed from the flare. On days that the flare 
receives regulated material, we are proposing that owners or operators 
of flares in the specified subset monitor visible emissions at a 
minimum of once per day while the flare is receiving regulated material 
using an observation period of 5 minutes and Method 22. Additionally, 
whenever regulated material is routed to a flare in the specified 
subset and there are visual emissions from the flare, we are proposing 
that another 5-minute visible emissions observation period be performed 
using Method 22, even if the minimum required daily visible emission 
monitoring has already been performed. For example, if an employee 
observes visible emissions, the owner or operator of the flare would 
perform a 5-minute Method 22 observation to check for compliance upon 
initial observation or notification of such event. In addition, in lieu 
of daily visible emissions observations performed using Method 22, we 
are proposing that owners and operators be allowed to use video 
surveillance cameras. We believe that video surveillance cameras would 
be at least as effective as the proposed daily 5-minute visible 
emissions observations using Method 22.
    We are also proposing to extend the observation period for a flare 
in the specified subset to 2 hours whenever visible emissions are 
observed for greater than 1 continuous minute during any of the 5-
minute observation periods. Refer to 40 CFR 63.2450(e)(5) and 40 CFR 
63.670(c) and (h) for these proposed requirements. We acknowledge that 
operating a flare near the incipient smoke point (the point at which 
black smoke begins to form within the flame) results in good combustion 
at the flare tip; however, smoking flares can contribute significantly 
to emissions of particulate matter that is 2.5 micrometers in diameter 
or smaller. Thus, while increasing the allowable period for visible 
emissions may be useful from an operational perspective, we do not 
believe the allowable period for visible emissions should be increased 
to more than 5 minutes in any 2-hour period. We solicit comment on the 
proposed allowable period for visible emissions from flares.
    As discussed later in this section, we are proposing additional 
operational and monitoring requirements for flares in the specified 
subset that we expect will result in owners or operators of MCPUs 
installing equipment that can be used to fine-tune and control the 
amount of assist steam or air introduced at the flare tip such that 
combustion efficiency of the flare will be maximized. These monitoring 
and control systems will assist these flare owners or operators to 
operate near the incipient smoke point without exceeding the visible 
emissions limit. While combustion efficiency may be highest at the 
incipient smoke point, it is not significantly higher than the 
combustion efficiency achieved by the proposed operating limits 
discussed in section IV.A.1.d of this preamble. As seen in the 
performance curves for flares, there is very limited improvement in 
flare performance beyond the performance achieved at the proposed 
operating limits (see technical memorandum titled Petroleum Refinery 
Sector Rule: Operating Limits for Flares, in Docket ID Item No. EPA-HQ-
OAR-2010-0682-0206, which has been incorporated into the docket for 
this rulemaking). We solicit comments and data on appropriate periods 
of visible emissions that would encourage operation at the incipient 
smoke point.
    In addition, we are proposing that the owner or operator establish 
the smokeless capacity of each flare in the specified subset based on 
design specification of the flare, and that the visible emissions 
limitation only apply when the flare vent gas flow rate is below its 
smokeless capacity. We are proposing a work practice standard for the 
limited times (i.e., during emergency releases) when the flow to a 
flare in the specified subset exceeds the smokeless capacity of the 
flare, based on comments the EPA received on the proposed Petroleum 
Refinery Sector rule. Refer to 40 CFR 63.2450(e)(5) and 40 CFR 
63.670(o) for these proposed provisions. In the Petroleum Refinery 
Sector final rule, the EPA explained that numerous comments on the 
proposal suggested that flares are not designed to meet the visible 
emissions requirements when operated beyond their smokeless capacity 
(80 FR 75178). According to commenters, flares are typically designed 
to operate in a smokeless manner at 20 to 30 percent of full hydraulic 
load. Thus, they claimed, flares have two different design capacities: 
A ``smokeless capacity'' to handle normal operations and typical 
process variations and a ``hydraulic load capacity'' to handle very 
large volumes of gases discharged to the flare as a result of an 
emergency shutdown. According to commenters, this is inherent in all 
flare designs and has not previously been an issue because flare 
operating limits did not apply during malfunction events.
    For this proposed work practice standard, owners or operators would 
need to develop a flare management plan for flares in the specified 
subset that identifies procedures for limiting discharges to the flare 
as a result of process upsets or malfunctions that cause the flare to 
exceed its smokeless capacity. In addition, for any flare in the 
specified subset that exceeds both the smokeless design capacity and 
visible emissions limit, we are proposing that owners or operators 
would need to conduct a specific root cause analysis

[[Page 69201]]

and take corrective action to prevent the recurrence of a similarly 
caused event (similar to the prevention measures we are proposing in 
this rule to minimize the likelihood of a PRD release, see section 
IV.A.2.a of this preamble). We are proposing that if the root cause 
analysis indicates that the exceedance of the visible emissions limit 
is caused by operator error or poor maintenance, then the exceedance 
would be considered a deviation from the work practice standard. We are 
also proposing that a second event within a rolling 3-year period from 
the same root cause on the same equipment would be considered a 
deviation from the standard. Further, we are proposing that events 
caused by force majeure would be excluded from a determination of 
whether there has been a second event. Finally, and again excluding 
force majeure events, we are proposing that a third visible emissions 
limit exceedance occurring from the same flare in a rolling 3-year 
period would be a deviation from the work practice standard, regardless 
of the cause. We are proposing at 40 CFR 63.2550(i) to define a force 
majeure event as a release of HAP, either directly to the atmosphere 
from a PRD 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 MCPU's ability to operate.
    With regard to the proposed rolling 3-year period for assessing a 
deviation of the work practice standard, the EPA evaluated the impacts 
of different frequencies and time periods to the number of events that 
would be the ``backstop'' (i.e., a deviation of the standard) to ensure 
that corrective actions are meaningfully applied (see 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). The EPA assumed that the best performers 
would have no more than one event every 7 years, or a probability of 
14.3 percent of having an event in any given year. The EPA found that, 
over a long period of time such as 20 years, about half of these best 
performers would have two events in a 3-year period, which would still 
result in about half of the ``best performing'' flares having a 
deviation from the work practice standard if it was limited to two 
events in 3 years. Conversely, the EPA found that over a long time 
period such as 20 years, only 6 percent of the best performing flares 
would have three events in 3 years over this same time horizon. Based 
on this analysis, three events in 3 years would appear to be 
``achievable'' for the average of the best performing flares.
c. Flare Tip Velocity
    This action consolidates provisions related to flare tip velocity 
for flares in the specified subset. The MON references the flare 
provisions in 40 CFR 63.11(b) (through reference of 40 CFR part 63, 
subpart G, 40 CFR part 63, subpart SS, and Table 12 to 40 CFR part 63, 
subpart FFFF), which specify maximum flare tip velocities based on 
flare type (non-assisted, steam-assisted, or air-assisted) and the net 
heating value of the flare vent gas. For MON facilities using flares as 
APCDs, it is estimated that approximately 90 percent of these flares 
are either steam- or air-assisted (see 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). These maximum flare tip velocities are required to 
ensure that the flame does not ``lift off'' the flare (i.e., a 
condition where a flame separates from the tip of the flare and there 
is space between the flare tip and the bottom of the flame), which 
could cause flame instability and/or potentially result in a portion of 
the flare gas being released without proper combustion. We are 
proposing to remove the cross-reference to the General Provisions for 
flares in the specified subset and instead cross-reference 40 CFR part 
63, subpart CC, to consolidate the provisions for maximum flare tip 
velocity into the MON as a single equation, irrespective of flare type 
(i.e., steam-assisted, air-assisted, or non-assisted). Refer to 40 CFR 
63.2450(e)(5) and 40 CFR 63.670(d), (i), and (k) for these proposed 
provisions.
    Based on analysis conducted for the Petroleum Refinery Sector final 
rule, the EPA identified air-assisted test runs with high flare tip 
velocities that had high combustion efficiencies (see technical 
memorandum, Petroleum Refinery Sector Rule: Evaluation of Flare Tip 
Velocity Requirements, in Docket ID Item No. EPA-HQ-OAR-2010-0682-
0212). These test runs exceeded the maximum flare tip velocity limits 
for air-assisted flares using the linear equation in 40 CFR 
63.11(b)(8). When these test runs were compared with the test runs for 
non-assisted and steam-assisted flares, air-assisted flares appeared to 
have the same operating envelope as the non-assisted and steam-assisted 
flares. Therefore, for air-assisted flares in the specified subset, we 
are proposing the use of the same equation that non-assisted and steam-
assisted flares currently use to establish the flare tip velocity 
operating limit. We are also proposing that the owner or operator 
determine the flare tip velocity on a 15-minute block average basis. 
See section IV.A.1.e of this preamble for our rationale for proposing 
to use a 15-minute block averaging period for determining continuous 
compliance.
    In addition, we are proposing the same work practice standard for 
flare tip velocity during emergency releases (when the flow to the 
flare exceeds the smokeless capacity of the flare) as we are proposing 
for visible emissions for flares in the specified subset. Refer to 40 
CFR 63.2450(e)(5) and 40 CFR 63.670(o) for these proposed provisions. 
Specifically, instead of owners and operators meeting the flare tip 
velocity operating limit at all times for flares in the specified 
subset, we are proposing that the owner or operator establish the 
smokeless capacity of each flare based on design specification of the 
flare, and that the flare tip velocity operating limit would only apply 
when the flare vent gas flow rate is below its smokeless capacity. We 
are proposing a work practice standard for flares in the specified 
subset for the limited times (i.e., during emergency releases) when the 
flow to the flare exceeds the smokeless capacity of the flare, based on 
comments the EPA received on the proposed Petroleum Refinery Sector 
rule. In the Petroleum Refinery Sector final rule, the EPA explained 
that numerous comments on the proposal suggested that flares are not 
designed to meet the flare tip velocity requirements when being 
operated beyond their smokeless capacity (80 FR 75178). According to 
commenters, flares are commonly operated during emergency releases at 
exit velocities greater than 400 feet per second (which is 270 miles 
per hour), and this is inherent in all flare designs and has not 
previously been an issue because flare operating limits did not apply 
during malfunction events.
    For the proposed work practice standard, owners or operators would 
develop a flare management plan for flares in the specified subset 
identifying procedures that they intend to follow in order to limit 
discharges to the flare as

[[Page 69202]]

a result of process upsets or malfunctions that cause the flare to 
exceed its flare tip velocity operating limit. In addition, we are 
proposing that owners or operators would conduct a specific root cause 
analysis for flares in the specified subset and take corrective action 
to prevent the recurrence of a similarly caused event, similar to the 
prevention measures we are proposing in this rule to minimize the 
likelihood of a PRD release (see section IV.A.2.a of this preamble), 
for any flare event above smokeless design capacity that also exceeds 
the flare tip velocity operating limit. We are proposing that if the 
root cause analysis indicates that the exceedance is caused by operator 
error or poor maintenance, then the exceedance would be considered a 
deviation from the work practice standard. We are also proposing that a 
second event where the flare tip velocity operating limit is exceeded 
within a rolling 3-year period from the same root cause on the same 
equipment would be considered a deviation from the standard. Further, 
we are proposing that events caused by force majeure (see section 
IV.A.1.b of this preamble for a proposed definition of force majeure) 
would be excluded from a determination of whether there has been a 
second event. Finally, and again excluding force majeure events, we are 
proposing that a third event where the flare tip velocity operating 
limit is exceeded exceedance occurring from the same flare in a rolling 
3-year period would be a deviation from the work practice standard, 
regardless of the cause. As previously explained in section IV.A.1.b of 
this preamble, we believe no more than three events in 3 years appear 
to be ``achievable'' for the average of the best performing flares. We 
solicit comment on the proposed work practice standard for flare tip 
velocity during emergency releases (when the flow to the flare exceeds 
the smokeless capacity of the flare).
    Finally, we are also proposing not to include the provision for the 
special flare tip velocity equation in the General Provisions at 40 CFR 
63.11(b)(6)(i)(A) for non-assisted flares in the specified subset with 
hydrogen content greater than 8 percent. This equation, which was 
developed based on limited data from a chemical manufacturer, has very 
limited applicability for flares used as APCDs in the Miscellaneous 
Organic Chemical Manufacturing source category because it only provides 
an alternative for non-assisted flares with large quantities of 
hydrogen. Available data indicates that approximately 90 percent of the 
flares used at MON facilities are either steam-assisted or air-
assisted. Furthermore, we are proposing compliance alternatives that we 
believe provide a better way for flares in the specified subset with 
high hydrogen content to comply with the rule while ensuring proper 
destruction performance of the flare (see section IV.A.3.d of this 
preamble for the proposed compliance alternatives). Therefore, for non-
assisted flares in the specified subset with hydrogen content greater 
than 8 percent that are used as ACPDs, we are not proposing to include 
this special flare tip velocity equation as a compliance alternative. 
We request comment on the need to include this equation.
d. Net Heating Value of the Combustion Zone Gas
    The current provisions for flares in 40 CFR 63.11(b) specify that 
the flare vent gas meet a minimum net heating value of 200 British 
thermal units per standard cubic foot (Btu/scf) for non-assisted flares 
and 300 Btu/scf for air- and steam-assisted flares. The MON references 
these provisions (through reference of 40 CFR part 63, subpart G, 40 
CFR part 63, subpart SS, and Table 12 to 40 CFR part 63, subpart FFFF), 
but neither the General Provisions nor the MON include specific 
requirements for monitoring the net heating value of the flare vent 
gas. Moreover, recent flare testing results indicate that the minimum 
net heating value alone does not address instances when the flare may 
be over-assisted because it only considers the gas being combusted in 
the flare and nothing else (e.g., no assist media). However, many 
industrial flares use steam or air as an assist medium to protect the 
design of the flare tip, promote turbulence for the mixing, induce air 
into the flame, and operate with no visible emissions. Using excessive 
steam or air results in dilution and cooling of flared gases and can 
lead to operating a flare outside its stable flame envelope, reducing 
the destruction efficiency of the flare. In extreme cases, over-
steaming or excess aeration can snuff out a flame and allow regulated 
material to be released into the atmosphere without complete 
combustion. As previously noted, because available data indicate that 
approximately 90 percent of all flares used as APCDs in the 
Miscellaneous Organic Chemical Manufacturing source category are either 
steam- or air-assisted, it is critical that we ensure the assist media 
is accounted for in some form. Recent flare test data have shown that 
the best way to account for situations of over-assisting is to consider 
the gas mixture properties at the flare tip in the combustion zone when 
evaluating the ability to combust efficiently. As discussed in the 
introduction to this section, the external peer review panel concurred 
with our assessment that the combustion zone properties at the flare 
tip are critical parameters to know in determining whether a flare will 
achieve good combustion. The General Provisions, however, solely rely 
on the net heating value of the flare vent gas, and we have determined 
that is not sufficient for the flares at issue.
    In this proposal, in lieu of requiring compliance with the 
operating limits for net heating value of the flare vent gas in the 
General Provisions, we are proposing to cross-reference 40 CFR part 63, 
subpart CC, to include in the MON a single minimum operating limit for 
the net heating value in the combustion zone gas (NHVcz) of 270 Btu/scf 
during any 15-minute period for steam-assisted, air-assisted, and non-
assisted flares in the specified subset. Refer to 40 CFR 63.2450(e)(5) 
and 40 CFR 63.670(e) and (m) for these proposed provisions. The Agency 
believes, given the results from the various data analyses conducted 
for the Petroleum Refinery Sector rule, that this NHVcz operating limit 
promulgated for flares in the Petroleum Refinery Sector source category 
is also appropriate and reasonable and will ensure flares in the 
specified subset meet the HAP destruction efficiencies in the standard 
at all times when operated in concert with the other proposed flare 
provisions (e.g., pilot flame, visible emissions, and flare tip 
velocity requirements) (see the memoranda titled Petroleum Refinery 
Sector Rule: Operating Limits for Flares and Flare Control Option 
Impacts for Final Refinery Sector Rule, in Docket ID Item No. EPA-HQ-
OAR-2010-0682-0206 and EPA-HQ-OAR-2010-0682-0748, respectively). In 
addition, we are proposing 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 for flares in the 
specified subset; however, owners or operators who wish to use the 
corrected hydrogen heat content must have a system capable of 
monitoring for the hydrogen content in the flare vent gas. The 1,212 
Btu/scf value is based on a comparison between the lower flammability 
limit and net heating value of hydrogen compared to light organic 
compounds and has been used in several consent decrees issued by the 
EPA. Based on analyses conducted for the Petroleum Refinery Sector rule 
(see the memorandum titled Flare Control Option Impacts for Final 
Refinery Sector

[[Page 69203]]

Rule, in Docket ID Item No. EPA-HQ-OAR-2010-0682-0748), the EPA 
determined that using a 1,212 Btu/scf value for hydrogen greatly 
improves the correlation between combustion efficiency and the 
combustion zone net heating value over the entire array of data.
    Furthermore, in addition to the NHVcz operating limit, we are 
proposing a net heating value dilution parameter (NHVdil) for certain 
flares in the specified subset that operate with perimeter assist air. 
Refer to 40 CFR 63.2450(e)(5) and 40 CFR 63.670(f) and (n) for these 
proposed provisions. For air-assisted flares, use of too much perimeter 
assist air can lead to poor flare performance. Furthermore, based on 
our analysis of the air-assisted flare datasets (see technical 
memorandum, Petroleum Refinery Sector Rule: Operating Limits for 
Flares, in Docket ID Item No. EPA-HQ-OAR-2010-0682-0206), we determined 
a NHVdil of 22 British thermal units per square foot is necessary to 
ensure that there is enough combustible material available to 
adequately combust the gas and pass through the flammability region and 
also ensure that degradation of flare performance from excess aeration 
does not occur. We found that including the flow rate of perimeter 
assist air in the calculation of the NHVcz does not identify all 
instances of excess aeration and could (in some instances) even allow 
facilities to send very dilute vent gases to the flare that would not 
combust (i.e., vent gases below their lower flammability limit could be 
sent to flare). Instead, the data suggest that the diameter of the 
flare tip, in concert with the amount of perimeter assist air (and 
other parameters used to determine NHVcz), provides the inputs 
necessary to calculate whether this type of flare is over-assisted. 
This dilution parameter is consistent with the combustion theory that 
the more time the gas spends in the flammability region above the flare 
tip, the more likely it will combust. Also, because both the volume of 
the combustion zone (represented by the diameter) and how quickly this 
gas is diluted to a point below the flammability region (represented by 
perimeter assist air flow rate) characterize this time, it is logical 
that we propose such a parameter.
    We also found that some assist steam lines are purposely designed 
to entrain air into the lower or upper steam at the flare tip; and for 
flare tips with an effective tip diameter of 9 inches or more, there 
are no flare tip steam induction designs that can entrain enough assist 
air to cause a flare operator to have a deviation from the NHVdil 
operating limit without first deviating from the NHVcz operating limit. 
Therefore, we are proposing to allow owners or operators of flares in 
the specified subset whose only assist air is from perimeter assist air 
entrained in lower and upper steam at the flare tip and with a flare 
tip diameter of 9 inches or greater to comply only with the NHVcz 
operating limit. Steam-assisted flares with perimeter assist air and an 
effective tip diameter of less than 9 inches would remain subject to 
the requirement to account for the amount of assist air intentionally 
entrained within the calculation of NHVdil. However, we recognize that 
this assist air cannot be directly measured, but the quantity of air 
entrained is dependent on the assist steam rate and the design of the 
steam tube's air entrainment system. Therefore, we are proposing 
provisions to specify that owners or operators of these smaller 
diameter steam-assisted flares in the specified subset use the steam 
flow rate and the maximum design air-to-steam ratio of the steam tube's 
air entrainment system for determining the flow rate of this assist 
air. Using the maximum design ratio will tend to over-estimate the 
assist air flow rate, which is conservative with respect to ensuring 
compliance with the NHVdil operating limit.
    Finally, we are proposing that owners or operators record and 
calculate 15-minute block average values for these parameters. Our 
rationale for selecting a 15-minute block averaging period is provided 
in section IV.A.1.e of this preamble. We solicit comment on the 
proposed revisions related to NHVcz.
e. Data Averaging Periods for Flare Gas Operating Limits
    Except for the visible emissions operating limits as described in 
section IV.A.1.b, we are proposing to use a 15-minute block averaging 
period for each proposed flare operating parameter (i.e., presence of a 
pilot flame, flare tip velocity, and NHVcz) to ensure that flares in 
the specified subset are operated within the appropriate operating 
conditions. We consider a short averaging time to be the most 
appropriate for assessing proper flare performance because flare vent 
gas flow rates and composition can change significantly over short 
periods of time. Furthermore, because destruction efficiency can fall 
precipitously when a flare is controlling vent gases below (or outside) 
the proposed operating limits, short time periods where the operating 
limits are not met could seriously impact the overall performance of 
the flare. Refer to the Petroleum Refinery Sector rule preambles (79 FR 
36880 and 80 FR 75178) for further details supporting why we believe a 
15-minute averaging period is appropriate.
    Given the short averaging times for the operating limits, we are 
proposing special calculation methodologies to enable owners or 
operators to use ``feed forward'' calculations to ensure compliance 
with the operating limits on a 15-minute block average for flares in 
the specified subset. Specifically, we propose using the results of the 
compositional analysis determined just prior to a 15-minute block 
period for the next 15-minute block average. Owners or operators of 
flares in the specified subset will then know the vent gas properties 
for the upcoming 15-minute block period and can adjust assist gas flow 
rates relative to vent gas flow rates to comply with the proposed 
operating limits. In other words, ``feed forward'' means that owners or 
operators would use the net heating value in the vent gas (NHVvg) going 
into the flare in one 15-minute period to adjust the assist media 
(i.e., steam or air) and/or the supplemental gas in the next 15-minute 
period, as necessary, to calculate an NHVcz limit of 270 Btu/scf or 
greater using the proposed equation. We recognize that when a 
subsequent measurement value is determined, the instantaneous NHVcz 
based on that compositional analysis and the flow rates that exist at 
the time may not be above 270 Btu/scf. We are proposing that this is 
not a deviation from the operating limit. Rather, we propose that the 
owner or operator is only required to make operational adjustments 
based on that information to achieve, at a minimum, the net heating 
value limit for the subsequent 15-minute block average. We are, 
however, proposing that failure to make adjustments to assist media or 
supplemental natural gas using the NHVvg from the previous period in 
the equation provided for calculating an NHVcz limit of 270 Btu/scf, 
would be a deviation from the operating limit. Alternatively, because 
the owner or operator could directly measure the NHVvg on a more 
frequent basis, such as with a calorimeter (and optional hydrogen 
analyzer), the process control system is able to adjust more quickly, 
and the owner or operator can make adjustments to assist media or 
supplemental natural gas more quickly. In this manner, the owner or 
operator is not limited by relying on NHVvg data that may not represent 
the current conditions. We are, therefore, also proposing that the 
owner or operator may opt to use the NHVvg in such instances from the 
same period to comply with the operating limit. For

[[Page 69204]]

examples of ``feed forward'' calculations, please see Attachment 3 of 
the memorandum titled Flare Control Option Impacts for Final Refinery 
Sector Rule, in Docket ID Item No. EPA-HQ-OAR-2010-0682-0748.
    We are also proposing to clarify that when determining compliance 
with the flare tip velocity and combustion zone operating limits 
specified in 40 CFR 63.670(d) and (e), the initial 15-minute block 
period starts with the 15-minute block that includes a full 15 minutes 
of the flaring event. In other words, we are proposing to clarify that 
the owner or operator demonstrate compliance with the velocity and 
NHVcz requirements starting with the block that contains the fifteenth 
minute of a flaring event; and the owner or operator is not required to 
demonstrate compliance for the previous 15-minute block in which the 
event started and contained only a fraction of flow. We solicit comment 
on these proposed revisions.
f. Flares in Dedicated Service
    In lieu of requiring the composition of the vent gas and the NHVvg 
to be continuously monitored, we are proposing an alternative 
monitoring approach for flares in the specified subset that are in 
dedicated service that have consistent composition and flow. We believe 
that these types of flares, which have limited flare vent gas streams, 
do not need to have the same type of ongoing monitoring requirements as 
those with more variable waste streams. Thus, we are proposing an 
option that owners or operators can use to demonstrate compliance with 
the operating requirements for flares in the specified subset that are 
in dedicated service to a specific emission source, such as a transfer 
rack operation consistently loading the same material. We are proposing 
that owners or operators will need to submit an application for the use 
of this alternative compliance option. We are proposing that the 
application include a description of the system, characterization of 
the vent gases that could be routed to the flare based on a minimum of 
seven grab samples (14 daily grab samples for continuously operated 
flares), and specification of the net heating value that will be used 
for all flaring events (based on the minimum net heating value of the 
grab samples). In other words, for flares in the specified subset that 
are in dedicated service, we are proposing that the minimum NHVvg 
determined from the grab samples could be used in the equation at 40 
CFR 63.670(m)(1) for all flaring events to determine NHVcz. We are also 
proposing to allow engineering estimates to characterize the amount of 
gas flared and the amount of assist gas introduced into the system. For 
example, we believe that the use of fan curves to estimate air assist 
rates would be acceptable. We propose that flare owners or operators 
would use the net heating value determined from the initial sampling 
phase and measured or estimated flare vent gas and assist gas flow 
rates, if applicable, to demonstrate compliance with the standards. 
Refer to 40 CFR 63.2450(e)(5) and 40 CFR 63.670(j)(6) for these 
proposed provisions. Finally, for owners and operators that must comply 
with the continuous monitoring requirements, we are proposing 
additional clarifications and requirements at 40 CFR 63.2450(e)(5) when 
using a gas chromatograph or mass spectrometer for compositional 
analysis. We solicit comment on the proposed revisions related to 
flares in dedicated service.
g. Pressure-Assisted Multi-Point Flares
    Pressure-assisted flares are conceptually similar, yet technically 
different in both design and operation compared to more traditional 
elevated flare tip designs (e.g., steam-assisted, air-assisted, and 
non-assisted flare tips). Pressure-assisted flares operate by taking 
advantage of the pressure upstream of the flare tip to create a 
condition whereby air is drawn into contact and mixed with high exit 
velocity flared gas, resulting in smokeless flare operation and 
emissions reductions at least equivalent to those of traditional flares 
types, if properly designed and operated. Pressure-assisted flares can 
be used in a single flare burner type layout or in staged arrays with 
many identical flare burners. These staged arrays can be elevated or at 
ground level; however, we are only aware of ground level staged array 
systems, that are commonly referred to as MPGF, at three facilities in 
the Miscellaneous Organic Chemical Manufacturing source category that 
emit ethylene oxide or produce olefins and/or polyolefins. Two of these 
MPGFs are used solely as a secondary flare to control large emissions 
events that result during periods of SSM. MPGFs have multiple (e.g., 
hundreds) flare burners at ground level. The flare burners in a MPGF 
are designed with a staging system that opens and closes staging valves 
according to gas pressure in the flare header such that the stages, and 
accompanying flare burners for those stages, are activated to control 
emissions as the flare vent gas flow and pressure increase in the flare 
header, or are deactivated as the flare vent gas flow and pressure 
decrease in the flare header. The flare burners in a MPGF are typically 
lit with a pilot flame system where the first burners on a stage are 
lit by the pilot flame and the flame propagates (i.e., cross-lights) 
down the stage to the remaining burners on the stage (e.g., like how 
burners on a gas grill would light). The MPGF system is surrounded by a 
panel type fence to allow air in for combustion as well as to protect 
nearby workers from the radiant heat of the flare system.
    MPGF are often used as secondary flares to control large emissions 
events that result during periods of SSM. With the elimination of the 
SSM exemption (see section IV.E.1 of this preamble for additional 
discussion), proposing requirements for this unique flare type for 
flares in the specified subset is an important consideration given that 
some facilities currently use them as APCD. Based on our review of 
recently approved AMEL requests for MPGF and the underlying data 
analyses that supported those decisions (see section II.D of this 
preamble), MPGF can achieve at least equivalent reductions in volatile 
organic compounds (VOC) and organic HAP to traditional elevated flares; 
however, different operating requirements are needed for these flare 
types to ensure a high level of control is achieved given that the 
individual flare burners are designed to operate at high velocities 
(i.e., up to sonic velocity). Important considerations for proper 
design and operation of MPGF center around the following: (1) Flare 
flame stability, (2) pilot flame presence and its interplay with proper 
cross-lighting, (3) operation of the MPGF with no visible emissions, 
and (4) monitoring of certain parameters of the MPGF and the vent gases 
it controls for purposes of compliance assurance.
    In reviewing the initial MPGF AMEL requests by Dow Chemical and 
ExxonMobil (80 FR 8023-8030, February 13, 2015), the Agency noted two 
general conclusions from the test data supporting the AMEL requests 
that were consistent with 1985 studies \27\ conducted by the EPA on 
pressure-assisted flares. The first general conclusion was that ``flare 
head design can influence the flame stability curve.'' The second 
general conclusion was that ``stable flare flames and high (>98-99 
percent) combustion and destruction efficiencies are attained when 
flares are operated within operating envelopes specific to each flare 
burner and gas

[[Page 69205]]

mixture tested. Operation beyond the edge of the operating envelope can 
result in rapid flame de-stabilization and a decrease in combustion and 
destruction efficiencies.'' In reviewing all the available data in the 
MPGF AMEL docket (i.e., Docket ID No. EPA-HQ-OAR-2014-0738), we found 
these two general observations were still valid conclusions. The data 
clearly show that for some test runs flare flameouts occurred, meaning 
the flares were not operated within the proper envelope to produce a 
stable flame. In reviewing these data, we observed that all flare 
flameouts occurred for the various burners/waste gas mixtures tested 
below an NHVcz of 800 Btu/scf. Thus, we selected a minimum NHVcz of 800 
Btu/scf to ensure the MPGF at facilities in the Miscellaneous Organic 
Chemical Manufacturing source category that emit ethylene oxide or 
produce olefins and/or polyolefins are operated within the proper 
envelope to produce a stable flame and achieve high destruction 
efficiencies at least equivalent to those as the underlying MON 
standards. Above this level, no flare flameouts are observed, and high 
combustion/destruction efficiencies at least equivalent to those as the 
underlying MON MACT standards are achieved. Thus, to that end, we are 
proposing to not allow use of the ``feed forward'' calculation approach 
(discussed in section IV.A.1.e of this preamble) to demonstrate 
compliance with the NHVcz limit of 800 Btu/scf. We are only proposing 
allowance of complying with a straight 15-minute block average for 
these flare types in the specified subset.
---------------------------------------------------------------------------

    \27\ Pohl, J. and N. Soelberg. 1985. Evaluation of the 
efficiency of industrial flares: Flare head design and gas 
composition. EPA-600/2-85-106. Prepared for U.S. EPA Office of Air 
Quality Planning and Standards.
---------------------------------------------------------------------------

    Another unique characteristic of MPGF is that they may use a cross-
lighting pilot flame system as a means of ignition to initially combust 
the waste gases sent to the flare burners on a particular staged array. 
Thus, we also reviewed the equipment-specific set-ups in the test data 
that allowed for successful cross-lighting of MPGF. Based on review of 
the data, it appears that one option would be for facilities to conduct 
performance demonstrations to demonstrate successful cross-lighting on 
a minimum of three burners (i.e., as outlined in the Framework for 
Streamlining Approval of Future Pressure-Assisted MPGF AMEL Requests, 
81 FR 23480, April 21, 2016). However, given the data before us in the 
MPGF AMEL docket, and rather than requiring facilities to conduct a 
performance demonstration, it appears that an equipment standard that 
sets an upper limit on the distance between burners of 6 feet will 
ensure a successful cross-lighting on a stage of burners in a MPGF.
    Furthermore, in reviewing the site-specific AMEL standards that 
facilities are complying with for MPGF,\28\ we believe these same site-
specific standards, if applied to all MPGF in the specified subset, 
would demonstrate at least equivalent emissions reductions to the 
underlying MON MACT standards as well as demonstrate at least 
equivalent reductions to the new operational and monitoring 
requirements we are proposing for more traditional, elevated flare 
tips. Therefore, we are proposing that owners or operators of MPGF for 
the specified flare subset (1) Maintain an NHVcz>=800 Btu/scf over a 
short averaging period (i.e., 15-minutes); (2) continuously monitor the 
NHVcz and flare vent gas flow rate; (3) continuously monitor for the 
presence of a pilot flame, and if cross-lighting is occurring on a 
particular stage of burners, ensuring that the stage has a minimum of 
two pilots per stage that are capable of igniting all flare vent gases 
sent to that stage; (4) operate the MPGF with no visible emissions 
(except for 5 minutes during any 2 consecutive hours); (5) maintain a 
distance of no greater than 6 feet between any two burners on a stage 
of burners that use cross-lighting; and (6) monitor to ensure the 
staging valves for each stage of the MPGF operate properly so that the 
flare will control vent gases within the range of the tested conditions 
based on the flare manufacturer's recommendations.
---------------------------------------------------------------------------

    \28\ 80 FR 52426, August 31, 2015; 81 FR 23480, April 21, 2016; 
and 82 FR 27822, June 19, 2017.
---------------------------------------------------------------------------

    Finally, although we are unaware of any MON facilities that use 
multi-point elevated flares in the specified flare subset, we recognize 
that an owner or operator may elect to use this type of flare design in 
the future. Given the design similarities of a multi-point elevated 
flare when compared to a MPGF (i.e., each flare type uses pressure-
assisted burners with staged arrays), we determined that our analyses 
of the test data (including our review of approved AMEL requests) 
related to MPGF that control waste gases could also apply to multi-
point elevated flares in the specified subset that combust waste gases. 
Therefore, we are proposing that owners and operators of multi-point 
elevated flares meet the same requirements that we are proposing for 
MPGF. In other words, the proposed requirements discussed in this 
section of the preamble would apply to all pressure-assisted multi-
point flares (i.e., MPGF and multi-point elevated flares) in the 
specified subset. We are soliciting comment on whether this approach is 
appropriate, and whether test data are available for multi-point 
elevated flares that control waste gases from MON facilities. We are 
also soliciting comment on whether the proposed requirements for 
pressure-assisted multi-point flares should ultimately supersede the 
currently approved MPGF AMEL requests at MON facilities.
h. Impacts of the Flare Operating and Monitoring Requirements
    The EPA expects that the newly proposed requirements for flares in 
the specified subset that are discussed in this section will affect 
flares at 21 facilities nationwide. We assumed that these facilities 
each operate one flare that either controls ethylene oxide emissions or 
controls emissions from an olefins and/or polyolefins process. The ACC 
provided the EPA a distribution of flares by type for 68 MON facility 
flares at 18 facilities. We used this information to estimate the flare 
type for each of the 21 flares at MON facilities that control ethylene 
oxide emissions or produce olefins and/or polyolefins. Based on this 
information, we estimate that the majority of these flares (about 90 
percent) have traditional elevated flare tip designs (e.g., steam-
assisted, air-assisted, and non-assisted flare tips) that receive flare 
vent gas flows on a regular basis (i.e., other than during periods of 
SSM). We also reviewed consent decrees and approved AMEL requests 
issued to these facilities. Based on this information, five of the 21 
MON facilities are expected to already have the monitoring equipment 
needed to better control their flares. Specifically, two facilities 
operate under consent decree only, two facilities operate MPGF under 
approved AMEL requests only, and one facility both operates under 
consent decree and also operates a MPGF under an approved AMEL request. 
Therefore, we estimate that only 16 flares are expected to incur costs, 
based on the assumption that owners and operators of flares at the five 
facilities with consent decrees and/or approved AMEL requests already 
have the monitoring equipment in place. Costs were estimated for each 
flare for a given facility, considering current monitoring systems 
already installed on each individual flare. Given that the same type of 
equipment is used for flares in the Miscellaneous Organic Chemical 
Manufacturing source category and for the petroleum refinery sector, 
costs for any additional monitoring systems needed were estimated based 
on installed costs received from petroleum refineries and,

[[Page 69206]]

if installed costs were unavailable, costs were estimated based on 
vendor-purchased equipment. The baseline emission estimate and the 
emission reductions achieved by the proposed flare requirements were 
estimated by back-calculating from the NEI-reported VOC and HAP 
controlled emissions assuming a 93.1-percent baseline control 
efficiency, derived from the best available data.\29\ The results of 
the impact estimates are summarized in Table 3 of this preamble. We 
note that the requirements for flares in the specified subset that we 
are proposing in this proposal will ensure compliance with the MACT 
standards in the MON when flares are used as an APCD. Because we are 
not changing the underlying MACT standards in the MON, we did not 
include any of the estimated excess emissions from flares in the 
summary of total estimated emissions reductions for this action. 
However, we estimate that the proposed operational and monitoring 
requirements have the potential to reduce excess emissions from flares 
in the specified subset by approximately 260 tpy of HAP and 1,300 tpy 
of VOC. The VOC compounds are non-methane, non-ethane total 
hydrocarbons. According to the modeling file we used to assess risk 
(see section III.C.1 of this preamble), there are approximately 30 
individual HAP compounds included in the emission inventory for flares 
in the specified subset, but many of these are emitted in trace 
quantities. The majority of the HAP emissions from flares are 
attributable to HCl, hexane, vinyl acetate, and 1,3-butadiene. Note 
that this analysis does not consider costs incurred for flares outside 
of the specified subset for which an owner or operator may choose to 
opt-in to the proposed requirements. For more detail on the impact 
estimates, see the technical memorandum titled Control Option Impacts 
for Flares Located in the Miscellaneous Organic Chemical Manufacturing 
Source Category, which is available in the docket for this rulemaking.
---------------------------------------------------------------------------

    \29\ API, the National Petrochemical and Refiners Association 
(NPRA; now known as the American Fuels and Petrochemical 
Manufacturers (AFPM)), and the ACC provided the EPA with a dataset 
that includes detailed hourly operational information for 38 steam-
assisted flares, characterizing different operating conditions by 
waste gas flow rate, steam flow rate, waste gas composition, and 
duration of that operating condition.

   Table 3--Nationwide Cost Impacts for Flares at MON Facilities That
    Control Emissions of Ethylene Oxide or Emissions From Olefins or
                        Polyolefins Processes \1\
------------------------------------------------------------------------
                                     Total capital     Total annualized
       Control description            investment       costs (million $/
                                      (million $)             yr)
------------------------------------------------------------------------
Flare Operational and Monitoring                17.0                4.05
 Requirements...................
Work Practice Standards for                     0.16                0.04
 Flares Operating Above Their
 Smokeless Capacity.............
                                 ---------------------------------------
    Total.......................                17.2                4.09
------------------------------------------------------------------------
\1\ Costs are calculated for the year 2016.

2. Vent Control Bypasses
a. Pressure Relief Devices
    The MON defines several terms applicable to process vents at 40 CFR 
63.2550. The current definition of ``continuous process vent'' excludes 
``relief valve discharges,'' and instead, the MACT standard in the MON 
recognizes relief valve discharges to be the result of malfunctions. 
The acronym ``PRD'' means pressure relief device and is common 
vernacular to describe the variety of devices regulated as pressure 
relief valves (see the end of this section for our proposed definitions 
of pressure relief device and relief valve, to provide clarity). PRDs 
are designed to remain closed during normal operation. Typically, the 
Agency considers PRD releases as the result of an overpressure in the 
system caused by operator error, a malfunction such as a power failure 
or equipment failure, or other unexpected cause that results in 
immediate venting of gas from process equipment to avoid safety hazards 
or equipment damage.
    The MON currently regulates PRDs when they are seated through 
equipment leak provisions that are applied only after the pressure 
relief occurs (i.e., conduct monitoring with EPA Method 21 of Appendix 
A-7 to 40 CFR part 60 after each pressure release using a leak 
definition of 500 ppm); however, these provisions do not apply to an 
emissions release from a PRD. In addition, the MON follows the EPA's 
then-practice of exempting SSM events from otherwise applicable 
emission standards. Consequently, with PRD releases defined as 
unplanned, nonroutine, and the result of malfunctions, the MON did not 
restrict PRD releases to the atmosphere but instead treated them in the 
same manner as malfunctions subject to the SSM exemption provision. In 
Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), the Court 
determined that the SSM exemption violates the CAA. Section IV.E.1 of 
this preamble contains additional discussions on the removal of the SSM 
exemption provision for this source category. As a result, we evaluated 
the MACT standard in the MON for PRD discharges to ensure a standard 
continuously applies, consistent with the Sierra Club SSM decision.
    CAA section 112(d)(1) specifies that the EPA may ``distinguish 
among classes, types, and sizes of sources'' when establishing 
standards. (In establishing standards under CAA section 112(d), the EPA 
may ``distinguish among classes, types, and sizes of sources within a 
category or sub-category.'' CAA section 112(d)(1). See Sierra Club v. 
EPA, 479 F.3d 875, 885 (D.C. Cir. 2007)). We are proposing two 
subcategories of PRDs for the MACT standard in the MON to distinguish 
between classes of PRDs: (1) PRDs designed to vent through a closed-
vent system to a control device or to a process, fuel gas system, or 
drain system (referred to as PRDs that vent to a control system); and 
(2) PRDs designed to vent to the atmosphere, if a release were to 
occur. We are proposing to subcategorize PRDs by class because of 
design differences between the numerous PRDs at MON facilities that 
vent to a control system and that vent to the atmosphere. Currently, 
MON facilities are required to evaluate PRDs as part of their risk 
management and process safety management programs. When implementing 
these programs, facilities identify PRDs that they intend to control as 
compared to those they elect not to control (and that have the 
potential to vent to the atmosphere if a release were to occur). 
Facilities do not control certain PRDs because of technical or site-
specific safety considerations, such as PRDs that

[[Page 69207]]

release chemicals that could be incompatible with vent streams in 
downstream controls.
    We evaluated each subcategory of PRDs separately to ensure that a 
standard continuously applies. Essentially, PRDs that vent to a control 
system are already complying with the process vent standards and are, 
thus, presumably, already appropriately controlled. However, PRDs that 
vent to atmosphere cannot meet the current continuous process vent 
standards. Therefore, we examined whether it would be feasible to 
regulate PRDs that vent to atmosphere under CAA section 112(d)(2) and 
(3). As detailed here, we determined it was feasible to regulate PRDs 
that vent to atmosphere under CAA section 112(h) and are proposing work 
practice standards at 40 CFR 63.2480(e) that are intended to reduce the 
number of PRD releases and will incentivize owners or operators to 
eliminate the causes of PRD releases to the atmosphere.
    No MON facility is subject to numeric emission limits for PRDs that 
vent to the atmosphere. Further, we do not believe it is 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. CAA section 112(h)(1) states that 
the EPA may prescribe a work practice standard or other requirement, 
consistent with the provisions of CAA sections 112(d) or (f), in those 
cases where, in the judgment of the Administrator, it is not feasible 
to enforce an emission standard. CAA section 112(h)(2)(B) further 
defines the term ``not feasible'' in this context as meaning that ``the 
application of measurement technology to a particular class of sources 
is not practicable due to technological and economic limitations.'' We 
consider it appropriate to establish a work practice standard for PRDs 
that vent to atmosphere as provided in CAA section 112(h), because the 
application of a measurement methodology for PRDs that vent to 
atmosphere is not practicable due to technological and economic 
limitations. First, it is not practicable to use a measurement 
methodology for PRD releases that vent to atmosphere. PRDs are designed 
to remain closed during normal operations and release emissions only 
during nonroutine and unplanned events, and the venting time can be 
very short and may vary widely in composition and flow rate. These 
unique event characteristics make it infeasible to collect a grab 
sample of the gases when a PRD release occurs, and a single grab sample 
would also likely not account for potential variation in vent gas 
composition. Additionally, it would not be cost-effective to construct 
an appropriate conveyance and install and operate continuous monitoring 
systems for each individual PRD that vents to atmosphere in order to 
attempt to quantitatively measure a release event that may occur only a 
few times in a 3-year period. (See U.S. Sugar Corp. v. EPA, 830 F.3d 
579, 664-67 (2016).) Further, we have not identified any available, 
technically feasible continuous emission monitoring system (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. Rather, we have 
identified only monitoring systems capable of alerting an owner or 
operator when a PRD release occurs. Consequently, we concluded that it 
is appropriate to establish a work practice standard for PRDs that vent 
to atmosphere as provided in CAA section 112(h).
    We also reviewed information about MON facilities to determine how 
the best performers are minimizing emissions from PRDs that vent to 
atmosphere. We first reviewed the requirements in the EPA's Chemical 
Accident Prevention Provisions (40 CFR part 68) and Occupational Safety 
and Health Administration's (OSHA) Process Safety Management rule (29 
CFR 1910.119). These rules focus on planning for and minimizing or 
preventing scenarios which would result in releases of chemicals. For 
example, as stated in Appendix C to the OSHA rule, ``Process safety 
management is the proactive identification, evaluation and mitigation 
or prevention of chemical releases that could occur as a result of 
failures in process, procedures or equipment.'' The rules are 
applicable to any equipment in the process, and relief valves are 
identified in each rule as an applicable source to evaluate. The EPA 
and OSHA rules have similar requirements, except that applicability 
determination is unique to each rule. Owners or operators are subject 
to the EPA's Chemical Accident Prevention Provisions at 40 CFR part 68 
if a process has more than a threshold quantity of a regulated 
substance. Regulated substances and their thresholds are listed at 40 
CFR 68.130. Owners or operators are subject to OSHA's Process Safety 
Management rule at 29 CFR 1910.119 if a process involves either a 
chemical that is above specified threshold quantities (listed in 
appendix A to 29 CFR 1910.119) or a Category 1 flammable gas or liquid. 
MON facilities may be subject to the Chemical Accident Prevention 
Provisions rule, as identified in their title V permit (40 CFR 68.215 
requires permits to list part 68 as an applicable requirement, if 
subject). As a result, we further reviewed this rule for consideration 
in developing the work practice standard.
    The EPA's Chemical Accident Prevention Provisions require a 
prevention program. Facilities subject to the MON would fall under 
prevention program 3. Prevention program 3 includes the following: 
Documentation of process safety information, conducting a hazard 
analysis, documentation of operating procedures, employee training, on-
going maintenance, and incident investigations. The process safety 
information documented must include information pertaining to the 
hazards of the regulated substances in the process, the technology of 
the process, and the process equipment (including relief valves). When 
conducting the hazard analysis, facilities must identify, evaluate, and 
control the hazards in the process; controls may consider the 
application of detection methodologies (e.g., process monitoring and 
control instrumentation) to provide early warning of releases. The 
operating procedures must address multiple operating scenarios (e.g., 
normal operations, startup, emergency shutdown) and provide 
instructions for safely conducting process activities. Conducting the 
hazard analysis and documenting operating procedures are similar to 
prevention measures, discussed below, though we note a specific number 
of measures or controls is not specified for the program 3 prevention 
program. Incident investigations must document the factors that 
contributed to an incident and any resolutions and corrective actions 
(incident investigations are consistent with root cause analysis and 
corrective action, discussed below). Facilities are also required to 
document this information in a Risk Management Plan that must be 
updated at least every 5 years.
    Next, we considered that some companies operating MON facilities 
also own and operate petroleum refineries and may have established 
company-wide best practices as a result of specific state and federal 
requirements. For example, petroleum refineries and chemical plants 
located in certain counties in California are subject to and complying 
with specific requirements for PRDs such as the Bay Area Air Quality 
Management District

[[Page 69208]]

(BAAQMD) Rule 8-28-304 and South Coast Air Quality Management District 
(SCAQMD) Rule 1173. The BAAQMD rule requires implementation of three 
prevention measures, and both rules require root cause analysis and 
corrective action for certain PRDs. These rules also formed the basis 
of the work practice standards promulgated for PRD releases at 
petroleum refineries in the Petroleum Refinery Sector RTR performed by 
the EPA (80 FR 75178, December 1, 2015).
    Considering our review of the EPA's Chemical Accident Prevention 
Provisions and company-wide best practices that MON facilities may have 
implemented, we expect that the best performing MON facilities have 
implemented a program for PRDs that vent to the atmosphere 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 used this information 
as the basis of the work practice standards that we are proposing at 40 
CFR 63.2480(e). Examples of prevention measures include the following: 
Flow indicators, level indicators, temperature indicators, pressure 
indicators, routine inspection and maintenance programs, operator 
training, inherently safer designs, safety instrumentation systems, 
deluge systems, and staged relief systems where the initial PRD 
discharges to a control system.
    We are also proposing a limit on the number of PRD releases that 
would result in a deviation from the work practice standard for PRDs 
that vent to the atmosphere. We believe setting criteria to determine a 
deviation is necessary for the work practice to be effective. We 
considered limits on the number of PRD releases in both 3- and 5-year 
periods. Based on a Monte Carlo analysis of random rare events (as 
conducted for the Petroleum Refinery Sector rule \30\), we note that it 
is quite likely to have two or three events in a 5-year period when a 
long time horizon (e.g., 20 years) is considered. Therefore, we are 
proposing to limit the number of PRD releases from a single PRD to 
either one, two, or three (depending on the root cause) in a 3-year 
period as the basis of a deviation from the work practice standard. We 
are proposing that it is a deviation from the work practice standard if 
a single PRD that vents to atmosphere has two releases within a 3-year 
period due to the same root cause. We believe that this provision will 
help ensure that root cause/corrective action are conducted 
effectively. Otherwise, we are proposing that it is a deviation from 
the work practice standard if a single PRD that vents to atmosphere has 
three releases within a 3-year period for any reason. In addition, we 
are proposing that any PRD release for which the root cause was 
determined to be operator error or poor maintenance is a deviation from 
the work practice standard. Refer to 40 CFR 63.2480(e)(3)(v) for these 
proposed provisions. We are proposing that ``force majeure'' events 
would not be included when counting the number of releases. ``Force 
majeure'' events result from natural disasters, acts of war or 
terrorism, or external power curtailment beyond the facility's control. 
These types of events are beyond the control of the owner or operator. 
We are providing that these events should not be included in the event 
count, but that they would be subject to the root cause analysis in 
order to confirm whether the release was caused by a force majeure 
event. Based on our cost assumptions, the nationwide capital cost for 
complying with the PRD work practice requirements is $6.03 million and 
the annualized capital costs is $0.58 million.
---------------------------------------------------------------------------

    \30\ See 80 FR 75217, December 1, 2015.
---------------------------------------------------------------------------

    In addition, we believe that it is appropriate to exclude certain 
types of PRDs that have very low potential to emit based on their type 
of service, size, and/or pressure from the proposed work practice 
standard for PRD releases that vent to atmosphere. Both the Chemical 
Accident Prevention Provisions and the California petroleum refinery 
PRD rules also exempt or impose simpler requirements for certain PRDs. 
We are proposing 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. Each of the types of PRDs that we are proposing are not 
subject to the work practice standard are discussed in greater detail 
here. With regard to PRDs with a design release pressure of less than 
2.5 psig, it is technically infeasible to pipe sources with a release 
pressure of less than 2.5 psig to a flare (or other similar control 
system) because the back pressure in the flare header system generally 
exceeds 2.5 psig. Therefore, we are proposing that PRDs with a design 
release pressure of less than 2.5 psig are not subject to the work 
practice standard. With regard to PRDs in heavy liquid service, any 
release from a PRD in heavy liquid service would have a visual 
indication of a leak and any repairs to the valve would have to be 
further inspected and, if necessary, repaired under the existing 
equipment leak provisions. Therefore, we are proposing that PRDs in 
heavy liquid service are not subject to the work practice standard. In 
addition, we are proposing that PRDs designed solely to release due to 
liquid thermal expansion are not subject to the work practice standard. 
We expect that releases from these thermal relief valves would be 
insignificant. Finally, we are also proposing that pilot-operated PRDs 
(where emissions can be released to the atmosphere through a pilot 
discharge vent) and balanced bellow PRDs (where emissions can be 
released to the atmosphere through a bonnet vent) are not subject to 
the work practice standard, if the primary release valve associated 
with the pilot-operated or balanced bellows PRD is vented through a 
control system. Pilot-operated and balanced bellows PRDs are primarily 
used for pressure relief when the back pressure of the discharge vent 
may be high or variable. Conventional pressure relief devices act on a 
differential pressure between the process gas and the discharge vent. 
If the discharge vent pressure increases, the vessel pressure at which 
the PRD will open increases, potentially leading to vessel over-
pressurization that could cause vessel failure. Balanced bellows PRDs 
use a bellow to shield the pressure relief stem and top portion of the 
valve seat from the discharge vent pressure. A balanced bellows PRD 
will not discharge gas to the atmosphere during a release event, except 
for leaks through the bonnet vent due to bellows failure or fatigue. 
Pilot-operated PRDs use a small pilot safety valve that discharges to 
the atmosphere to effect actuation of the primary valve or piston, 
which then discharges to a control system. Balanced bellows or pilot 
operated PRDs are considered a reasonable and necessary means to safely 
control the primary PRD release.
    For all PRDs in organic HAP service, owners or operators would 
still be required to comply with the leak detection and repair (LDAR) 
provisions, as they are currently applicable. Therefore, all PRDs that 
vent to the atmosphere would still perform LDAR to ensure the PRD 
properly reseats if a release does occur, and PRDs that vent to control 
systems would still be exempt from LDAR requirements given that if a 
release were to occur from this specific

[[Page 69209]]

class of PRDs, it would vent to a closed vent system and control 
device.
    Finally, to ensure compliance with the proposed work practice 
standard for PRDs that vent to the atmosphere, we are also proposing at 
40 CFR 63.2480(e)(3) that sources monitor these PRDs 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. Pressure release events from PRDs that vent to 
atmosphere have the potential to emit large quantities of HAP. When a 
pressure release occurs, it is important to identify and mitigate it as 
quickly as possible. For purposes of estimating the costs of this 
requirement, we assumed that operators would install electronic 
monitors on PRDs that vent to atmosphere to identify and record the 
time and duration of each pressure release. However, we are proposing 
to allow owners and operators to use a range of methods to satisfy 
these requirements, including the use of a parameter monitoring system 
(that may already be in place) on the process operating pressure that 
is sufficient to indicate that a pressure release has occurred as well 
as record the time and duration of that pressure release. Based on our 
cost assumptions, the nationwide capital cost of installing these 
electronic monitors is $12.7 million, and the annualized capital cost 
is $1.68 million per year.
    We also considered requiring all PRDs to be vented to a control 
device as a beyond-the-floor requirement. While this would provide 
additional emission reductions beyond those we are establishing as the 
MACT floor, these reductions come at significant costs. Assuming 25 
percent to 50 percent of PRDs already vent to a control device, the 
capital cost for controlling the remaining PRDs ranges from $2,540 
million to $5,070 million, and the annualized cost ranges from $330 
million to $660 million. The incremental cost effectiveness for 
requiring control of all PRDs that vent to atmosphere compared to the 
requirements described above exceeds $80 million per ton of HAP 
reduced. Consequently, we conclude that this is not a cost-effective 
option.
    The EPA is also proposing a requirement that any future installed 
pilot-operated PRDs be the non-flowing type. As previously noted, under 
CAA section 112(d)(1), the EPA may ``distinguish among classes, types, 
and sizes of sources'' when establishing standards. There are two 
designs of pilot-operated PRDs: Flowing and non-flowing. When a flowing 
pilot-operated PRD is actuated, the pilot discharge vent continuously 
releases emissions; however, when a non-flowing pilot-operated PRD is 
actuated, the pilot discharge vent does not vent continuously. Although 
we expect pilot discharge vent emissions to be minimal for both 
designs, limiting the future use of flowing pilot-operated PRDs is 
warranted to prevent continuous release of emissions. Therefore, we are 
proposing at 40 CFR 63.2480(e)(8) to require future installation and 
operation of non-flowing pilot-operated PRDs at all affected sources.
    The terms ``pressure release,'' ``pressure relief device,'' and 
``relief valve'' are not defined in the MON; therefore, we are 
proposing a definition for each of these terms at 40 CFR 63.2550(i) 
that would apply only to the MON standards. We are proposing to define 
``pressure release'' as 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. We are proposing to define ``pressure relief 
device'' as 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. 
We are proposing to define ``relief valve'' as a type of pressure 
relief device that is designed to re-close after the pressure relief.
    We solicit comment on all of the proposed revisions for PRDs. See 
the technical memorandum titled Review of Regulatory Alternatives for 
Certain Vent Streams in the Miscellaneous Organic Chemical 
Manufacturing Source Category, in the docket for this rulemaking for 
details on the assumptions and methodologies used in this analysis.
b. Closed-Vent System Containing Bypass Lines
    For a closed-vent system containing bypass lines that can divert 
the stream away from the APCD to the atmosphere, the MON requires the 
owner or operator to either (1) install, maintain, and operate a 
continuous parametric monitoring system for flow on the bypass line 
that is capable of detecting whether a vent stream flow is present at 
least once every 15 minutes or (2) secure the bypass line valve in the 
non-diverting position with a car-seal or a lock-and-key type 
configuration. Depending on the emission source, the MON references 
bypass line requirements in either 40 CFR part 63, subparts G, H, and 
SS, or 40 CFR part 65, subpart F. Under option (2), the owner or 
operator is also required to inspect the seal or closure mechanism at 
least once per month to verify the valve is maintained in the non-
diverting position (e.g., see 40 CFR 63.998(d)(1)(ii)(B) for more 
details). To ensure standards apply to MON emission sources at all 
times, we are proposing at 40 CFR 63.2450(e)(6) that an owner or 
operator may not bypass the APCD at any time, and if a bypass is used, 
then we are proposing that owners and operators estimate and report the 
quantity of organic HAP released. We are proposing this revision 
because bypassing an APCD could result in a release of regulated 
organic HAP to the atmosphere and to be consistent with Sierra Club v. 
EPA, 551 F.3d 1019 (D.C. Cir. 2008), where the Court determined that 
standards under CAA section 112(d) must provide for compliance at all 
times. We are also proposing that the use of a cap, blind flange, plug, 
or second valve on an open-ended valve or line is sufficient to prevent 
a bypass. We solicit comment on these proposed revisions.
c. Maintenance Activities
    The EPA is proposing that emission limits apply at all times 
consistent with Sierra Club v. EPA. We recognize that this proposed 
change for vent streams that are periodically discharged will affect 
certain maintenance activities such as those that require equipment 
openings, and we consider maintenance activities a separate class of 
startup and shutdown emissions because there must be a point in time 
when the equipment can be opened, and any remaining emissions are 
vented to the atmosphere. We also acknowledge that it would require a 
significant effort to identify and characterize each of these potential 
release points (e.g., for permitting purposes).
    We reviewed state permit conditions and determined the best 
performers' permits specify that they meet certain conditions before 
they open equipment to the atmosphere. The conditions include 
thresholds regarding the lower explosive limit (LEL) and the mass of 
gas that may be emitted. Therefore, we are proposing a work practice 
standard at 40 CFR 63.2455(d)(1)(i) that prior to opening process 
equipment to the

[[Page 69210]]

atmosphere during maintenance events, the equipment first be drained 
and purged to a closed system so that the hydrocarbon content is less 
than or equal to 10 percent of the LEL. For those situations where 10-
percent LEL cannot be demonstrated, we are proposing at 40 CFR 
63.2455(d)(1)(ii) that the equipment may be opened and vented to the 
atmosphere if 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. We are proposing this 5 psig threshold to 
acknowledge that a certain minimum pressure must exist for the flare 
header system (or other similar control system) to operate properly. We 
are also proposing at 40 CFR 63.2455(d)(1)(iii) that equipment may be 
opened when there is less than 50 pounds of VOC that may be emitted to 
the atmosphere.
    We also acknowledge that installing a blind flange to prepare 
equipment for maintenance may be necessary and by doing so, the owner 
or operator may not be able to meet the proposed maintenance vent 
conditions mentioned above (e.g., a valve used to isolate the equipment 
will not seat fully so organic material may continually leak into the 
isolated equipment). To limit the emissions during the blind flange 
installation, we are proposing at 40 CFR 63.2455(d)(1)(iv) 
depressurizing the equipment to 2 psig or less prior to equipment 
opening and maintaining pressure of the equipment where purge gas 
enters the equipment at or below 2 psig during the blind flange 
installation. The low allowable pressure limit will reduce the amount 
of process gas that will be released during the initial equipment 
opening, and the ongoing 2 psig pressure requirement will limit the 
purge gas rate. Together, these proposed provisions will limit the 
emissions during blind flange installation and will result in 
comparable emissions allowed under the proposed maintenance vent 
conditions mentioned above. We expect these situations to be rare and 
that the owner or operator would remedy the situation as soon as 
practical (e.g., replace the isolation valve or valve seat during the 
next turnaround in the example provided above). Therefore, we are only 
proposing that this alternative maintenance vent limit be used under 
those situations where the proposed primary limits (i.e., hydrocarbon 
content is less than or equal to 10 percent of the LEL, pressure is 
less than or equal to 5 psig, or VOC is less than 50 pounds) are not 
achievable and blinding of the equipment is necessary.
    We expect that all MON facilities already have standard procedures 
in place when performing equipment openings. As such, the only costs 
incurred are for recordkeeping after each non-conforming event. We are 
proposing that owners or operators document each circumstance under 
which the alternative maintenance vent limit is used, providing an 
explanation as to why other criteria could not be met prior to 
equipment blinding and an estimate of the emissions that occurred 
during the equipment blinding process. We calculated the annual costs 
to be $2,340 per year. We solicit comment on the proposed revisions 
related to maintenance activities. For additional details and 
discussion, see the technical memorandum titled 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.
d. Flares and Fuel Gas Systems
    The current definition of ``batch process vent'' at 40 CFR 
63.2550(i) states that ``gaseous streams routed to a fuel gas 
system(s)'' are not batch process vents. Gas streams going to fuel gas 
systems are also exempt from the current definition of ``continuous 
process vent'' at 40 CFR 63.2550(i) by referencing 40 CFR 63.107(h)(3). 
In addition, other MON standards (i.e., standards for storage tanks and 
transfer racks) also allow emissions to be routed to a fuel gas system 
for compliance purposes. A combustion device (typically a boiler or 
process heater) burning these gaseous streams as fuel effectively 
achieves the most stringent level of control (i.e., 98-percent organic 
HAP reduction or an outlet organic HAP concentration of 20 ppmv). 
However, there can be instances when gaseous streams from the fuel gas 
system that would otherwise be combusted in a boiler or process heater 
are instead routed to a flare (e.g., overpressure in the fuel gas 
system, used as flare sweep gas, used as flare purge gas). In cases 
where an emission source is required to be controlled in the MON 
standards but is routed to a fuel gas system, we are proposing 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, comply with the flare operating and 
monitoring requirements discussed in section IV.A.1 of this preamble. 
We recognize that this proposed provision may require owners or 
operators that use fuel gas for any purpose (e.g., flare sweep gas, 
flare purge gas, flare supplemental gas) in other flare APCDs that 
predominately control emissions from other source categories to comply 
with the proposed flare revisions discussed in section IV.A.1 of this 
preamble. Thus, in order to minimize this impact, we are proposing that 
any flare that utilizes 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 
that has processes and/or equipment in ethylene oxide service or that 
produces olefins or polyolefins comply with the flare operating and 
monitoring requirements discussed in section IV.A.1 of this preamble. 
We solicit comment on these proposed revisions.

B. What are the results of the risk assessment and analyses?

    As described in section III.C of this preamble, we conducted an 
inhalation risk assessment for all HAP emitted and multipathway and 
environmental risk screening assessments on the PB-HAP emitted. We 
present results of the risk assessment briefly below and in more detail 
in the document titled 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.
1. Chronic Inhalation Risk Assessment Results
    The results of the chronic baseline inhalation cancer risk 
assessment indicate that, based on estimates of current actual and 
allowable emissions, the MIR posed by the source category is 2,000-in-1 
million driven by ethylene oxide emissions from storage tanks (75 
percent), equipment leaks (15 percent), and process vents (8 percent). 
The total estimated cancer incidence based on actual and allowable 
emission levels is 0.4 excess cancer cases per year, or 1 case every 
2.5 years. The population exposed to cancer risks greater than 100-in-1 
million for actual and allowable emissions is approximately 18,000, and 
the population exposed to cancer risks greater than or equal to 1-in-1 
million is approximately 2,900,000 (see Table 4 of this preamble). In 
addition, the maximum modeled chronic noncancer TOSHI for the source 
category based on actual and allowable emissions is estimated to be 1.

[[Page 69211]]

                        Table 4--Miscellaneous Organic Chemical Manufacturing Source Category Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                         Estimated population at
                      Maximum         increased  risk of cancer \2\      Estimated annual        Maximum
   Number of         individual    ----------------------------------    cancer incidence        chronic         Maximum screening  acute noncancer HQ
 facilities \1\   cancer risk  (in     >100-in-1         >=1-in-1      (cases per year) \2\     noncancer
                   1 million) \2\       million          million                                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.

2. Screening Level Acute Risk Assessment Results
    As presented in Table 4 of this preamble, the estimated worst-case 
acute exposures to emissions from the Miscellaneous Organic Chemical 
Manufacturing source category result in a maximum acute HQ of 6 based 
on the REL for acrolein (the next highest dose-response value for 
acrolein, the AEGL-1, results in an HQ of 0.2). There are 11 additional 
instances of acute HQs greater than 1 from the source category. 
Evaluation of the screening-level acute risk assessment results is 
provided in a memo to the docket titled Evaluation of the Screening-
Level Acute Risk Assessment Results for the Miscellaneous Organic 
Chemical Manufacturing (MON) Source Category. Detailed information 
about the assessment is provided in 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 action.
3. Multipathway Risk Screening Results
    The multipathway risk screening assessment 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. 
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. 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.
    In evaluating the potential for multipathway risk from emissions of 
lead, we compared modeled annual lead concentrations to the primary 
NAAQS for lead (0.15 [micro]g/m\3\). The highest annual lead 
concentration of 0.0006 [micro]g/m\3\ is well below the NAAQS for lead, 
indicating low potential for multipathway risk of concern due to lead 
emissions.
4. Environmental Risk Screening Results
    As described in section III.A of this preamble, we conducted an 
environmental risk screening assessment for the Miscellaneous Organic 
Chemical Manufacturing source category for the following pollutants: 
Arsenic, cadmium, HCl, HF, lead, mercury (methyl mercury and mercuric 
chloride), and POMs.
    In the Tier 1 screening analysis for PB-HAP (other than lead, which 
was evaluated differently), arsenic and cadmium emissions had no 
exceedances for any ecological benchmark. Divalent mercury emissions at 
three facilities had Tier 1 exceedances for the surface soil threshold 
level (invertebrate and plant communities) by a maximum SV of 10. 
Methyl mercury emissions at three facilities had Tier 1 exceedances for 
the surface soil NOAEL (avian ground insectivores and mammalian 
insectivores) by a maximum SV of 20. POM emissions at four facilities 
had Tier 1 exceedances for the sediment no-effect level by a maximum SV 
of 10, and one facility had a Tier 1 exceedance of the sediment 
threshold level by a maximum SV of 2.
    A Tier 2 screening assessment was performed for divalent mercury, 
methyl mercury, and POM emissions. Neither divalent mercury, methyl 
mercury, nor POM emissions had a Tier 2 exceedance for any ecological 
benchmark.
    We did not estimate any exceedances of the secondary lead NAAQS.
    For HCl and HF, the average modeled concentration around each 
facility (i.e., the average concentration of all off-site data points 
in the modeling domain) did not exceed any ecological benchmark. In 
addition, each individual modeled concentration of HCl and HF (i.e., 
each off-site data point in the modeling domain) was below the 
ecological benchmarks for all facilities.
    Based on the results of the environmental risk screening analysis, 
we do not expect an adverse environmental effect as a result of HAP 
emissions from this source category.
5. Facility-Wide Risk Results
    An assessment of facility-wide (or ``whole facility'') risks was 
performed as described above to characterize the source category risk 
in the context of whole facility risks. Whole facility risks were 
estimated using the NEI-based data described in section III.C of this 
preamble. The maximum lifetime individual cancer risk posed by the 194 
modeled facilities, based on whole facility emissions, is 3,000-in-1 
million, with ethylene oxide emissions from fugitive emissions and 
flares from the Synthetic Organic Chemical Manufacturing, Polyether 
Polyols Production, and Miscellaneous Organic Chemical Manufacturing 
source categories driving the risk. Regarding the noncancer risk 
assessment, the maximum chronic noncancer HI posed by whole facility 
emissions is 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.
6. What demographic groups might benefit from this regulation?
    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 risk 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 risk from the Miscellaneous Organic 
Chemical Manufacturing source category across different demographic

[[Page 69212]]

groups within the populations living near facilities.\31\
---------------------------------------------------------------------------

    \31\ Demographic groups included in the analysis are: White, 
African American, Native American, Hispanic or Latino, other races 
and multiracial, people living below the poverty level, people 
living above the poverty level, over 25 and without a high school 
diploma, over 25 and with a high school diploma, and linguistically 
isolated people.
---------------------------------------------------------------------------

    The results of the demographic analysis are summarized in Table 5 
below. These results, for various demographic groups, are based on the 
estimated risk from actual emissions levels for the population living 
within 50 km of the facilities.

 Table 5--Miscellaneous Organic Chemical Manufacturing Source Category Demographic Risk Analysis Results--50 km
                                                Study Area Radius
----------------------------------------------------------------------------------------------------------------
                                                                               Population with
                                                                                 cancer risk        Population
                                                                               greater than  or    with hazard
                                                                               equal to  1 in 1   index greater
                                                                                   million            than 1
----------------------------------------------------------------------------------------------------------------
                                                                  Nationwide            Source Category
                                                             ---------------------------------------------------
Total Population............................................     317,746,049          2,858,862                0
                                                             ---------------------------------------------------
                                                                         White and Minority by Percent
rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr
White.......................................................             62%                44%               0%
Minority....................................................             38%                56%               0%
                                                             ---------------------------------------------------
                                                                              Minority by Percent
                                                             ---------------------------------------------------
African American............................................             12%                21%               0%
Native American.............................................            0.8%               0.2%               0%
Hispanic or Latino (includes white and nonwhite)............             18%                31%               0%
Other and Multiracial.......................................              7%                 4%               0%
                                                             ---------------------------------------------------
                                                                               Income by Percent
                                                             ---------------------------------------------------
Below Poverty Level.........................................             14%                16%               0%
Above Poverty Level.........................................             86%                84%               0%
                                                             ---------------------------------------------------
                                                                             Education by Percent
                                                             ---------------------------------------------------
Over 25 and without a High School Diploma...................             14%                20%               0%
Over 25 and with a High School Diploma......................             86%                80%               0%
                                                             ---------------------------------------------------
                                                                      Linguistically Isolated by Percent
                                                             ---------------------------------------------------
Linguistically Isolated.....................................              6%                 8%               0%
----------------------------------------------------------------------------------------------------------------

    The results of the Miscellaneous Organic Chemical Manufacturing 
source category demographic analysis indicate that emissions from the 
source category expose approximately 2,900,000 people to a cancer risk 
at or above 1-in-1 million and no one to a chronic noncancer TOSHI 
greater than 1. The percentages of the at-risk population in each 
demographic group (except for White and Non-Hispanic) are similar to or 
greater than their respective nationwide percentages.
    The methodology and the results of the demographic analysis are 
presented in a technical report, Risk and Technology Review--Analysis 
of Demographic Factors for Populations Living Near Miscellaneous 
Organic Chemical Manufacturing Source Category Operations, available in 
the docket for this action.

C. What are our proposed decisions regarding risk acceptability, ample 
margin of safety, and adverse environmental effect?

    As noted in section III of this preamble, the EPA sets standards 
under CAA section 112(f)(2) using ``a two-step standard-setting 
approach, with an analytical first step to determine an `acceptable 
risk' that considers all health information, including risk estimation 
uncertainty, and includes a presumptive limit on MIR of approximately 
1-in-10 thousand'' (54 FR 38045, September 14, 1989). For this 
proposal, the EPA estimated risks based on actual and allowable 
emissions from the Miscellaneous Organic Chemical Manufacturing source 
category, and we considered these in determining acceptability.
1. Residual Risks Under the Current MACT Provisions
    Under the current NESHAP, the risk results indicate that both the 
actual and allowable inhalation cancer risks to the individual most 
exposed are well above 100-in-1 million, which is the presumptive limit 
of acceptability. The estimated inhalation cancer risk to the 
individual most exposed to actual or allowable emissions from the 
source category is 2,000-in-1 million. The estimated incidence of 
cancer due to inhalation exposures is 0.4 excess cancer cases per year, 
or 1 excess case every 2.5 years. The population estimated to be 
exposed to cancer risks greater than 100-in-1 million for actual and 
allowable emissions is approximately 18,000, and the population 
estimated to be exposed to cancer risks greater than or equal to 1-in-1 
million is approximately 2,900,000.

[[Page 69213]]

    The estimated maximum chronic noncancer TOSHI from inhalation 
exposure for this source category is 1, indicating low likelihood of 
adverse noncancer effects from long-term inhalation exposures.
    The multipathway risk assessment results indicated a maximum cancer 
risk of 10-in-1 million based on ingestion exposures estimated using 
the health protective risk screening assumptions of a Tier 2 farmer 
exposure scenario.
    The acute risk screening assessment of reasonable worst-case 
inhalation impacts indicates a maximum acute HQ of 6 for acrolein based 
on the 1-hour REL. There are 11 additional instances of HQs greater 
than 1. For acute screening analyses, to better characterize the 
potential health risks associated with estimated reasonable worst-case 
acute exposures to HAP, we examine a wider range of available acute 
health metrics than we do for our chronic risk assessments. This is in 
acknowledgement that there are generally more data gaps and 
uncertainties in acute reference values than there are in chronic 
reference values. Examination of the range of available acute health 
metrics, in addition to the conservative (health-protective) 
assumptions built into the screening assessment, leads us to conclude 
that adverse effects from acute exposure to emissions from this 
category are not anticipated. More detailed information is provided in 
the memo to the docket titled Evaluation of the Screening-Level Acute 
Risk Assessment Results for the Miscellaneous Organic Chemical 
Manufacturing (MON) Source Category.
    Considering all of the health risk information and factors 
discussed above, including the uncertainties discussed in section III 
of this preamble (and taking into account uncertainties in the 2016 
updated URE for ethylene oxide and concerns raised by commenters, as 
discussed in section IV.C.3 of this preamble), the EPA proposes that 
the risks for this source category under the current MACT provisions 
are unacceptable. As noted in section II.A of this preamble, when risks 
are unacceptable, the EPA must determine the emissions standards 
necessary to reduce risk to an acceptable level without considering 
costs or technological feasibility. Therefore, we are proposing to 
revise the NESHAP for the Miscellaneous Organic Chemical Manufacturing 
(MON) source category pursuant to CAA section 112(f)(2) on the basis 
for risks being unacceptable.
2. Proposed Controls To Address Risks
    We evaluated several control options for reducing risks. Based on 
the results of the risk assessment, we have identified ethylene oxide 
as the primary contributor to risks. Ethylene oxide is primarily used 
at MON facilities as a feedstock in the production of miscellaneous 
chemicals, including alkyl alkanolamines, agrochemical products, 
ethoxylates, surfactants, and batch-produced polyols and glycols that 
are not subject to other NESHAP. Information gathered in this 
rulemaking indicates that, of the nine facilities identified with 
ethylene oxide emissions from MON processes, three have emissions from 
process vents, four have emissions from storage tanks, and all nine 
have emissions from equipment leaks. We did not identify any ethylene 
oxide emissions from other MON process units (e.g., heat exchange 
systems, wastewater, transfer operations); therefore, we are soliciting 
comment on data related to these other MON process units being 
potential sources of ethylene oxide emissions. Based on the available 
data, we analyzed control options for process vents, storage tanks, and 
equipment leaks to reduce risk.
    Process vents and storage tanks as a source of ethylene oxide 
emissions. Emissions of ethylene oxide can occur from several types of 
process vents, such as distillation columns, evaporator vents, and 
vacuum operations, as well as during vapor displacements and heating 
losses. Storage tanks are used to store liquid and gaseous feedstocks 
for use in a process, as well as to store liquid and gaseous products 
from a process. Ethylene oxide is typically stored under pressure as a 
liquified gas but may also be present at lower concentrations within 
non-pressurized storage tanks. The pressurized tanks typically use a 
blanket of inert gas, most often nitrogen, to maintain a non-
decomposable vapor space. Emissions from ethylene oxide pressure 
vessels occur both during loading operations and during the continuous 
purge of vapor space from non-loading operations.
    The current MON standards divide process vents into Group 1 process 
vents, which require controls, and Group 2 process vents, which 
generally do not require controls. The Group 1 and Group 2 designations 
for process vents are based on uncontrolled emissions levels for 
process vents from batch processes and on flow rate and the total 
resource index values for process vents from continuous processes. The 
current MON standard requires uncontrolled Group 1 process vents to 
reduce total HAP emissions by 98 percent by venting emissions through a 
closed-vent system to any combination of control devices or to vent 
emissions through a closed-vent system to a flare. The current MON 
standard also allows uncontrolled Group 1 batch process vents to be 
controlled by reducing uncontrolled emissions by 95 percent by venting 
through a closed-vent system to a recovery device. For process vents, 
the MON allows use of a design evaluation instead of a performance test 
to determine the percent reduction of control devices if the total 
uncontrolled HAP emissions being sent to the control device are less 
than 10 tpy.
    Similarly, the current MON standards divide storage tanks into 
Group 1 storage tanks, which require control, and Group 2 storage 
tanks, which generally do not. The Group 1 and Group 2 designation for 
storage tanks is based on the volume of the storage tank and vapor 
pressure of the material stored. The current MON standards require 
uncontrolled Group 1 storage tanks to reduce total HAP emissions by 95 
percent by venting emissions through a closed-vent system to any 
combination of control devices or to vent emissions through a closed-
vent system to a flare. The MON allows certain storage tanks to be 
controlled using the floating roof requirements in 40 CFR part 63, 
subpart WW, but this option is not applicable to storage tanks 
containing pure ethylene oxide. For storage tanks, the MON allows use 
of a design evaluation instead of a performance test to determine the 
percent reduction of control devices for any quantity of total 
uncontrolled HAP emissions being sent to the control device.
    Results from our risk assessment indicate that, of the source 
category MIR of 2,000-in-1 million, 8 percent of the risk is from 
process vent emissions of ethylene oxide and 75 percent of the risk is 
from storage tank emissions of ethylene oxide. The remaining risk is 
mostly from equipment leaks. To understand how to best address risk 
within the source category, we reviewed information gathered for this 
rulemaking for the three facilities identified with ethylene oxide 
emissions from process vents and the four facilities identified with 
ethylene oxide emissions from storage tanks. Of these emission process 
sources, only one storage tank was classified as Group 1 and was, 
therefore, required to control emissions. The remaining storage tanks 
and process vents are classified as Group 2 and are not currently 
required to control emissions. We note that the Group 1 storage tank 
contains pure

[[Page 69214]]

ethylene oxide, and the Group 2 storage tanks contain ethylene oxide at 
lower concentrations. Performance test data for the scrubber 
controlling the Group 1 storage tank were unavailable because a design 
evaluation was used to demonstrate compliance in lieu of performance 
testing. Based on results from the risk assessment, we also determined 
that the current MACT provisions for process vents and storage tanks do 
not result in sufficient reductions of ethylene oxide emissions, and, 
therefore, we evaluated available control technologies with a higher 
level of control, as discussed below.
    Proposed process vent and storage tank control technologies. To 
address the risk from ethylene oxide emissions from process vents and 
storage tanks, we performed a review of available control technologies 
and identified two options. The first technology is any control device 
capable of achieving 99.9-percent reduction of uncontrolled ethylene 
oxide emissions. The second technology is a flare meeting the proposed 
flare operating requirements discussed in section IV.A.1 of this 
preamble.
    An example of a control technology that can achieve 99.9-percent 
reduction of uncontrolled ethylene oxide emissions is packed-tower gas 
absorbers, also referred to in this proposal as scrubbers. These 
scrubbers control emissions from MON process vents and storage tanks by 
absorbing ethylene oxide into aqueous systems. The absorbed ethylene 
oxide can then be reacted to form glycol or can be recovered for 
downstream use. These systems can be designed to achieve very high 
ethylene oxide removal, with information provided by one scrubber 
vendor claiming that many of these systems achieve 99.9 percent or 
greater removal of ethylene oxide from vent gas. Information gathered 
in this rulemaking indicates that MON facilities with ethylene oxide 
emissions from process vents and storage tanks commonly use scrubbers 
to control emissions.
    Flares used as APCDs are expected to achieve 98-percent HAP 
destruction efficiencies when designed and operated according to the 
requirements in the General Provisions. As discussed in section IV.A.1 
of this preamble, studies on flare performance indicate that these 
General Provision requirements are inadequate to ensure proper 
performance of flares at chemical manufacturing facilities, 
particularly when either assist steam or assist air is used. It is 
expected that flares controlling ethylene oxide, which is highly 
flammable and, therefore, readily controlled by combustion controls, 
operating under the improved efficiency standards proposed in this 
preamble would achieve more than the 98-percent destruction efficiency 
required by the flare standard. While we did not identify any process 
vents or storage tanks in ethylene oxide service that are being 
controlled primarily by a flare, it is reasonable to expect that, in 
the case that these streams were controlled by a flare, these 
requirements would provide the same level of control as other high 
efficiency ethylene oxide controls.
    Equipment leaks as a source of ethylene oxide emissions. Emissions 
from equipment leaks occur in the form of gases or liquids that escape 
to the atmosphere through connection points (e.g., threaded fittings) 
or through the moving parts of valves, pumps, compressors, PRDs, and 
certain types of process equipment. The equipment leak provisions of 
the MON require meeting control requirements of 40 CFR part 63, 
subparts H (National Emission Standards for Organic Hazardous Air 
Pollutants for Equipment Leaks), UU (National Emission Standards for 
Equipment Leaks--Control Level 2 Standards), or 40 CFR part 65, subpart 
F (the Consolidated Air Rule for Equipment Leaks) for existing MON 
processes and 40 CFR part 63, subpart UU, or 40 CFR part 65, subpart F, 
for new MON processes. The applicable equipment is those components, 
including pumps, compressors, agitators, pressure relief devices, 
sampling collection systems, open-ended valves or lines, valves, and 
connectors that contain or contact material that is 5 percent by weight 
or more of organic HAP, operate 300 hours per year or more, and are not 
in vacuum service. The equipment leak requirements vary by equipment 
(component) type but require LDAR using monitoring with EPA Method 21 
of appendix A-7 to 40 CFR part 60 at certain frequencies (e.g., 
monthly, quarterly, every 2 quarters, annually) and have varying leak 
definitions (e.g., 500 ppm, 1,000 ppm, 10,000 ppm) depending on the 
type of service (e.g., gas and vapor service or in light liquid 
service). The LDAR requirements for components in heavy liquid service 
include sensory monitoring and the use of EPA Method 21 monitoring if a 
leak is identified.
    Results from our risk assessment indicate that, for the source 
category MIR of 2,000-in-1 million, approximately 15 percent is from 
equipment leak emissions of ethylene oxide. We note that the risk at a 
second facility is also greater than 100-in-1 million (i.e., 300-in-1 
million), with approximately 95 percent of the risk from equipment leak 
emissions of ethylene oxide.
    LDAR and equipment leak control technologies. To address the risk 
from ethylene oxide emissions from equipment leaks, we performed a 
review of available measures for reducing ethylene oxide emissions from 
components that were most likely to be in ethylene oxide service, which 
included pumps in light liquid service at batch processes, connectors 
in gas and vapor service or light liquid service, and valves in gas or 
light liquid service. This review relied on information from a 2011 
analysis that identified developments for equipment leaks at chemical 
manufacturing facilities and petroleum refineries,\32\ herein referred 
to as the 2011 equipment leaks analysis. We identified several 
developments in LDAR practices and processes, summarized here.
---------------------------------------------------------------------------

    \32\ Hancy. 2001. Memorandum from Hancy, C., RTI International 
to Howard, J., EPA/OAQPS. Analysis of Emissions Reduction Techniques 
for Equipment Leaks, December 21, 2011. EPA Docket ID No. EPA-HQ-
OAR-2010-0869.
---------------------------------------------------------------------------

    For light liquid pumps, we identified two options: (1) Lower the 
leak definition for batch pumps from 10,000 ppm to 1,000 ppm with 
monthly monitoring or (2) require the use of leakless pumps (i.e., 
canned pumps, magnetic drive pumps, diaphragm pumps, pumps with tandem 
mechanical seals, pumps with double mechanical seals) with annual 
monitoring with a leak definition of any reading above background 
concentration levels.
    For gas/vapor and light liquid connectors, we identified two 
options: (1) Require connector monitoring at a leak definition of 500 
ppm with annual monitoring or (2) require connector monitoring at a 
leak definition of 100 ppm with monthly monitoring.
    For gas/vapor and light liquid valves, we identified two options: 
(1) Require leakless valves (i.e., bellows seal gate and bellows seal 
globe valves with bellows welded to both the bonnet and stem) with 
annual monitoring with a leak definition of any reading above 
background concentration levels or (2) lower the leak definition from 
500 ppm to any reading above background concentration levels with 
monthly monitoring.
    Additional information on all evaluated control options is found in 
the memorandum titled Analysis of Control Options for Equipment Leaks 
at Processes that use Ethylene Oxide Located in the Miscellaneous 
Organic Chemical Manufacturing Source Category, in the docket for this 
rulemaking.

[[Page 69215]]

    Regulatory options. For process vents, storage tanks, and equipment 
leaks, we considered the control options described above for reducing 
risk from the source category. To reduce risk in the source category, 
we propose to require control of ethylene oxide for (1) process vents, 
(2) storage tanks, and (3) equipment ``in ethylene oxide service'' 
(defined in this proposal).\33\ For process vents and storage tanks, 
this control requirement is regardless of whether the equipment is 
classified as Group 1 or Group 2 for HAP.
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    \33\ For process vents, we are proposing 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 pounds per year (2.27 kilograms per year). For storage 
tanks of any capacity and vapor pressure, we are proposing 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 
parts per millions by weight (ppmw). We are proposing 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 are proposing 
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.
---------------------------------------------------------------------------

    In all cases, we are proposing that if information exists that 
suggests ethylene oxide could be present in these processes, then the 
process equipment is considered to be in ethylene oxide service unless 
sampling and analysis is performed to demonstrate that the process 
equipment does not meet the definition of being in ethylene oxide 
service. We are proposing sampling and analysis procedures at 40 CFR 
63.2492. Examples of information that could suggest ethylene oxide is 
present in a process stream 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.
    Based on the proposed applicability thresholds, we expect that 
eight facilities will be affected by the proposed ethylene oxide-
specific standards. Five of these eight facilities will be subject to 
the process vent and/or storage tank provisions; specifically, three 
facilities have process vents in ethylene oxide service and three 
facilities have storage tanks in ethylene oxide service. All eight 
facilities are expected to be subject to the equipment leak provisions.
    To reduce risks from process vents in ethylene oxide service, we 
are proposing 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, or to a concentration less than 1 ppmv for each process vent, 
or to less than 5 pounds per year for all combined process vents; or 
(2) venting emissions through a closed-vent system to a flare meeting 
the proposed flare operating requirements discussed in section IV.A.1 
of this preamble. To reduce risks from storage tanks in ethylene oxide 
service, we are proposing 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 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 
discussed in section IV.A.1 of this preamble. Additionally, we propose 
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 to ensure that the required 
level of control is achieved. We are also proposing 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 propose 
that owners or operators conduct periodic performance testing on non-
flare control devices in ethylene oxide service every 5 years.
    As previously stated, we are aware that MON facilities with 
ethylene oxide emissions from process vents and storage tanks commonly 
use scrubbers to control emissions. Based on our knowledge of these 
scrubbers, there is a difference in how these scrubbers operate in 
order to achieve high control efficiencies versus how a normal wet 
scrubber operates. The higher removal efficiency of ethylene oxide in 
these scrubbers is based on the absorption of ethylene oxide into the 
scrubber water and then conversion of ethylene oxide to ethylene 
glycol. This conversion is dependent on several factors--maintaining an 
acid environment to catalyze the reaction and having enough residence 
time in the scrubber for the reaction to occur. We are proposing 
continuous monitoring of operating parameters for these scrubbers to 
ensure that the factors needed for the reaction to occur are met, 
namely liquid-to-gas ratio, pressure drop across the scrubber, liquid 
feed pressure, liquid temperature, and pH. However, we are aware that 
several other parameters may also be important to monitor, such as 
maximum liquid flow rate, tank levels for the reactant and solution 
feed tanks, and ethylene glycol content of the tanks. We are requesting 
comment on the operating parameters we have proposed for these 
scrubbers and whether these additional operating parameters are 
necessary, and if so, how these parameter limits should be set and at 
what frequency they should be monitored.
    To reduce risks from equipment leaks, we identified two options 
that we are co-proposing for controlling emissions from MON equipment 
in ethylene oxide service, referred to here as equipment leak Control 
Option 1 and equipment leak Control Option 2. These two co-proposed 
options, presented in Table 6 and summarized here, provide a level of 
control beyond what is being proposed in the technology review for all 
MON equipment in HAP service.
    In equipment leak co-proposed Control Option 1, we are proposing 
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 are proposing 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 are proposing 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.
    As an alternative to Control Option 1, we are co-proposing 
equipment leak Control Option 2. Under co-proposed Control Option 2, we 
are proposing that more stringent equipment leak standards would apply 
to the facilities with a 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

[[Page 69216]]

Huntsman Performance), and detailed in Appendix 10 of the document 
titled 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. 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, equipment is 
considered leaking if an instrument reading above background is found. 
Furthermore, at the two higher risk facilities with a MIR greater than 
100-in-1 million, connectors in ethylene oxide service would be 
monitored monthly at a leak definition of 100 ppm. We are proposing 
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, 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.
    We solicit comment on each of the proposed requirements for process 
vents, storage tanks, and equipment in ethylene oxide service.

    Table 6--Summary of Equipment Leak Co-Proposed Control Options for MON Facilities Emitting Ethylene Oxide
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
Equipment Leak Control                            Applicability                       Control option description
 Option
----------------------------------------------------------------------------------------------------------------
1..........................  MON equipment in ethylene    Light Liquid Pumps........  Require leak definition of
                              oxide service.                                           1,000 ppm, monthly
                                                                                       monitoring.
                                                          Gas/Vapor and Light Liquid  Require leak definition of
                                                           Connectors.                 500 ppm, annual
                                                                                       monitoring.
2..........................  MON equipment in ethylene    Light Liquid Pumps........  Require pumps to have zero
                              oxide service at the two    Gas/Vapor and Light Liquid   emissions (e.g.,
                              facilities with cancer       Connectors.                 leakless), annual
                              risks >=100-in-1 million                                 monitoring.
                              (specifically, Lanxess                                  Require leak definition of
                              Corporation and Huntsman                                 100 ppm, monthly
                              Performance).                                            monitoring.
                                                          Gas/Vapor and Light Liquid  Require valves to have
                                                           Valves.                     zero emissions (e.g.,
                                                                                       leakless) with annual
                                                                                       monitoring or non-
                                                                                       leakless with quarterly
                                                                                       monitoring.
                             MON equipment in ethylene    Light Liquid Pumps........  Require leak definition of
                              oxide service at all other  Gas/Vapor and Light Liquid   1,000 ppm, monthly
                              facilities (excluding        Connectors.                 monitoring.
                              Lanxess Corporation and                                 Require leak definition of
                              Huntsman Performance).                                   500 ppm, annual
                                                                                       monitoring.
----------------------------------------------------------------------------------------------------------------

    Finally, in considering possible control options for equipment 
leaks, it is important to understand the uncertainties related to the 
modeled ethylene oxide equipment leak emissions. For Lanxess 
Corporation, the modeled equipment leak emissions were our best 
estimate, using component counts from the facility's title V permit 
application and emission factors, and were not based on measured 
emissions. Notably, this calculated emission estimate was higher than 
what was reported to the 2014 NEI and the 2014 Toxics Release 
Inventory. We used the highest emission estimate in our model run to be 
conservatively health protective but recognize that this may result in 
an overestimation of risk. For Huntsman Performance, the modeled 
equipment leak emissions were also our best estimate, using calculated 
emissions that were reported to the 2014 NEI, and were also not based 
on measured emissions. Although Huntsman Performance did report their 
equipment leak emissions, we do not know which components (e.g., pumps, 
valves, connectors, etc.) were responsible for these emissions, which 
introduces uncertainty regarding the effect that the proposed equipment 
leak controls would have on reducing equipment leak emissions. At 
Huntsman Performance, we are also aware that the ethylene oxide 
equipment leak emissions are not entirely from MON processes; however, 
we 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). Therefore, the risk for this facility is 
likely biased high due to our inability to distinguish between co-
located emissions. For both Lanxess Corporation and Huntsman 
Performance, because the ethylene oxide equipment leak emissions were 
derived from engineering calculations and are not based on measured 
values, there is considerable uncertainty regarding the appropriateness 
of the proposed LDAR and control provisions for light liquid pumps, 
gas/vapor and light liquid connectors, and gas/vapor and light liquid 
valves. As such, modeled risk reductions may not accurately reflect the 
actual effects of implementing the proposed controls. Furthermore, we 
have limited information regarding the use of leakless valves on 
streams that are in ethylene oxide service and, therefore, are 
soliciting comment on the applicability of these valves for MON 
equipment in ethylene oxide service.
3. Determination of Risk Acceptability
    As noted in sections II.A and III.A of this preamble and in the 
Benzene NESHAP, the EPA sets standards under CAA section 112(f)(2) 
using a two-step approach, with an analytical first step to determine 
whether risks are acceptable. This determination ``considers all health 
information, including risk estimation uncertainty, and includes a 
presumptive limit on maximum individual lifetime [cancer] risk (MIR) of 
approximately 1 in 10 thousand'' (54 FR 38045, September 14, 1989). A 
MIR of 1-in-10,000 (i.e., 100-in-1 million) alone does not constitute a 
bright line for making a risk acceptability determination. The level of 
the MIR is only one factor weighed in determining acceptability of 
risk. As risks increase above this benchmark, they become presumptively 
less acceptable under CAA section 112

[[Page 69217]]

and are weighed with other health risk measures and information, 
including risk estimation uncertainty, in making an overall judgment on 
acceptability.
    In some cases, the health risk measures and information taken 
together may provide a more realistic description of the magnitude of 
risk in the exposed population than that provided by the MIR alone. As 
such, we considered the results of the risk assessment (including the 
risk estimation uncertainty) and evaluated available control 
technologies and other measures (including the controls reviewed under 
the technology review) that could be applied to this source category to 
reduce the risks due to emissions of ethylene oxide from process vents, 
storage tanks, and equipment leaks without considering costs or 
technological feasibility. Additionally, as described previously in 
section IV.C.2, we are co-proposing two options for control of ethylene 
oxide emissions from equipment leaks (e.g., co-proposed Control Options 
1 and 2). Therefore, we present 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 controls for storage tanks, process vents, and either 
co-proposed equipment leak Control Option 1 or 2, in Table 7 and in the 
discussion below.

                                       Table 7--Nationwide Risk Impacts After Implementation of Proposed Controls
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Population
                                                                       --------------------------------     Cancer
             Control scenario                  MIR (x-in-1 million)        >=1-in-1        >100-in-1       incidence               Uncertainty
                                                                            million         million
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pre-Control Baseline.....................  2,000 (Lanxess, 300               2,900,000          18,000             0.4  ................................
                                            (Huntsman).
+ Storage Tank Controls..................  500 (Lanxess), 300                2,600,000           1,500             0.1  The effect of process vent and
                                            (Huntsman).                                                                  storage tank controls on
                                                                                                                         emissions is well understood
                                                                                                                         and generally certain.
+ Process Vent Controls..................  400 (Lanxess), 300                2,400,000             780             0.1
                                            (Huntsman).
Either, + Equipment Leak Control Option 1  200 (Lanxess), 300                2,300,000             300             0.1  Fugitive emissions estimates are
                                            (Huntsman).                                                                  uncertain and based on
                                                                                                                         engineering calculations.
                                                                                                                         Therefore, there is uncertainty
                                                                                                                         regarding the relevance of the
                                                                                                                         proposed equipment leak
                                                                                                                         controls (Lanxess, Huntsman).
                                                                                                                         Modeled fugitive emissions may
                                                                                                                         be subject to other NESHAP
                                                                                                                         which likely results in an
                                                                                                                         overestimation of risk
                                                                                                                         (Huntsman).
Or, + Equipment Leak Control Option 2....  100 (Lanxess), 200                2,100,000              30             0.1
                                            (Huntsman).
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Although the post-control risks are greater than 100-in-1 million 
(i.e., 200 to 300-in-1 million), due to the inherent health protective 
nature of our risk assessment methods and the uncertainties in this 
assessment, we believe that this risk assessment is more likely to 
overestimate rather than underestimate the risks. A brief discussion of 
the health protective aspects of the assessment, including 
uncertainties in the RTR emissions dataset, dispersion modeling, 
inhalation exposure estimates, and dose-response relationships was 
covered in section III.C.8. A more thorough discussion of these 
uncertainties is included in the 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 action.
    We note that the modeled risks due to emissions of ethylene oxide 
are sensitive to the URE applied. In this assessment, the modeled risks 
are largely driven by use of an EPA URE for ethylene oxide that was 
updated in December 2016 (i.e., 5 x 10-3 per ug/m\3\) on the 
basis of new human data.34 35 This updated URE is about 60 
times greater than the value used previously by EPA in its risk 
assessments (i.e., California EPA URE of 8.8 x 10-5 per ug/
m\3\, based on animal data).
---------------------------------------------------------------------------

    \34\ U.S. EPA. Evaluation of the Inhalation Carcinogenicity of 
Ethylene Oxide (CASRN 75-21-8) In Support of Summary Information on 
the Integrated Risk Information System (IRIS). December 2016. EPA/
635/R-16/350Fa. https://cfpub.epa.gov/ncea/iris/iris_documents/documents/toxreviews/1025tr.pdf.
    \35\ SAB. (2015). Science Advisory Board Review of the EPA's 
Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide: 
Revised external review draft--August 2014 [EPA Report]. (EPA-SAB-
15-012). Washington, DC: U.S. EPA, SAB. https://yosemite.epa.gov/
sab/sabproduct.nsf/fedrgstr_activites/
BD2B2DB4F84146A585257E9A0070E655/$File/EPA-SAB-15-012+unsigned.pdf.
---------------------------------------------------------------------------

    The UREs we use in our risk assessments generally provide an upper 
bound estimate of risk \36\ to be health protective in light of dose-
response modeling uncertainties. As noted above and in Section 
III.C.8.d, there are uncertainties inherent in all risk assessments, 
including uncertainties in the development of dose-response values. 
Consistent with EPA SAB recommendations,\37\ where a HAP is a risk 
driver, as is the case with ethylene oxide for this risk assessment, we 
examine the underlying technical information, including sources of risk 
estimation uncertainties. To better characterize the risks, we reviewed 
EPA's 2016 ethylene oxide dose-response assessment and the 
uncertainties in the dose-response relationships.
---------------------------------------------------------------------------

    \36\ IRIS glossary (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
    \37\ Recommendations of the SAB Risk and Technology Review 
Methods Panel are provided in their report, which is available at: 
https://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf.
---------------------------------------------------------------------------

    For the EPA's 2016 ethylene oxide URE, two aspects of uncertainty 
stand out as potentially contributing to the conservative (i.e., health 
protective) nature of the final 2016 URE. This is documented in the 
memorandum titled Sensitivity of Ethylene Oxide Risk Estimates to Dose-
Response Model Selection, which is available in the docket for this 
rulemaking, and as discussed further below.

[[Page 69218]]

    First, the updated IRIS URE for ethylene oxide is based on the 
upper confidence limit on the slope of the dose response curve. 
However, according to the 2005 Guidelines for Carcinogen Risk 
Assessment, when human data are available, it is reasonable to consider 
the central estimate rather than upper confidence limit for a URE.\38\ 
In the case of ethylene oxide, we do have human health data and, 
therefore, it is reasonable to consider the central estimate. The 
central estimate of the URE for ethylene oxide is 3 times lower than 
the upper confidence limit, as documented in the memorandum titled 
Sensitivity of Ethylene Oxide Risk Estimates to Dose-Response Model 
Selection, which is available in the docket for this rulemaking.
---------------------------------------------------------------------------

    \38\ Guidelines for Carcinogen Risk Assessment. Risk Assessment 
Forum. U.S. EPA. Washington, DC. March 2005.
---------------------------------------------------------------------------

    Second, we note that several dose-response models were considered 
during the 2016 IRIS assessment for two types of cancer: Breast cancer 
and lymphoid cancer. Considering multiple models ensures the selected 
model provides the best fit to the exposure data and helps quantify and 
characterize model and statistical uncertainty. The choice of model 
also has significant implications for the URE, particularly at the low 
end of the dose-response range.
    With regard to lymphoid cancer, the selected model provided the 
best fit and satisfied all SAB recommendations.\39\ However, there were 
statistical challenges associated with modeling the data. Therefore, in 
developing the dose-response value, the EPA considered other lymphoid 
cancer models that provided reasonably good fits to the exposure data 
and met some, but not all, of the SAB modeling criteria 
recommendations. For purposes of characterizing the uncertainty around 
the final 2016 IRIS URE, it is useful to consider the extent to which 
choosing an alternative lymphoid cancer model would have affected the 
value. In fact, one of the alternative lymphoid cancer models evaluated 
by the EPA would result in a URE 2 to 3 times lower than the IRIS URE, 
as documented in the memorandum titled Sensitivity of Ethylene Oxide 
Risk Estimates to Dose-Response Model Selection, which is available in 
the docket for this rulemaking.\40\ For breast cancer, there was a high 
level of statistical certainty with the model selected, and, therefore, 
we did not include alternative models in this uncertainty discussion.
---------------------------------------------------------------------------

    \39\ SAB advice on modeling criteria included (1) the 
recommendation to prioritize models with good fits in the low 
exposure range (e.g., spline models), (2) preference for using 
continuous individual-level exposure data over categorical results, 
and (3) selecting models that have a dose-response shape that is 
both biologically plausible and consistent with observed data.
    \40\ The memorandum notes that higher estimates of risk were 
obtained using other models that statistically fit the data. There 
were limitations with these models and they were not considered in 
the uncertainty analysis. However, a comprehensive analysis of 
alternative models would likely include some risk estimates higher 
than the IRIS unit risk.
---------------------------------------------------------------------------

    The EPA concludes that these uncertainties, noted in the 2016 IRIS 
assessment, provide important context for interpreting whether risks 
remaining post-control can be considered acceptable. In particular, we 
note that the central estimate compared to the upper confidence limit 
could result in a URE 3 times lower than the IRIS URE and an 
alternative dose-response model for lymphoid cancer could result in a 
URE 2-3 times lower. While EPA followed SAB recommendations regarding 
lymphoid model choice, we acknowledge the uncertainty inherent in this 
model selection, which is important for interpreting risk results. In 
fact, both the central estimate and an alternative dose-response model 
combined could result in a URE 5 times lower. This would reduce 
potential post-control risks to 60- to 100-in-1 million (from 200- to 
300-in-1 million).
    The updated URE was used in EPA's 2014 National Air Toxics 
Assessment (NATA). In September 2018, the ACC submitted a Request for 
Correction under the Information Quality Act asking that the ``NATA 
risk estimates for E.O.\41\ should be withdrawn and corrected to 
reflect scientifically-supportable risk values''.
---------------------------------------------------------------------------

    \41\ In this instance, ``E.O.'' refers to ``ethylene oxide.''
---------------------------------------------------------------------------

    Given the ACC's Request for Correction, in the HCl Production RTR 
proposed rule, the EPA requested comment on the use of the updated 
ethylene oxide URE for regulatory purposes (84 FR 1584; February 4, 
2019). The comment period for the proposed rule closed on April 26, 
2019, and the Agency received a number of comments on the updated 
ethylene oxide URE and its use for regulatory purposes. Those comments 
are included in Docket ID No. EPA-HQ-OAR-2018-0417, and the EPA is 
incorporating those comments into the docket for this rulemaking. 
Commenters provided comments both in support of and opposed to the 2016 
updated URE for ethylene oxide and its use for regulatory purposes. One 
commenter noted that the application of the URE would have wide-ranging 
implications on regulatory decision making. Commenters supporting the 
use of the 2016 updated URE noted that the IRIS assessment for ethylene 
oxide used the best available science, underwent review by Agency and 
non-Agency experts, as well as public review, and was published in a 
peer-reviewed journal. Commenters opposing the use of the 2016 updated 
URE noted concerns with the model and variables used to estimate pre-
1978 worker exposure estimates (and suggested an alternative model and 
alternative pre-1978 worker exposure estimates that would reflect 
higher pre-1978 exposures and affect the final URE), and another 
commenter indicated that they are developing their own cancer dose-
response value for ethylene oxide.
    In June 2019, the Texas Commission on Environmental Quality (TCEQ) 
issued a draft document for public review (``Ethylene Oxide 
Carcinogenic Dose-Response Assessment''), which concluded that 
``USEPA's ethylene oxide inhalation URF \42\ is not adequately 
supported by scientific data'' and instead proposed a unit risk factor 
(URF) of 1.4 x 10-6 per ug/m\3\. Specifically, TCEQ 
disagreed with the EPA's model selection as the basis for deriving a 
URE. TCEQ highlighted uncertainties in the URE arising from what it 
considered to be errors in the assumptions and calculations used to 
determine the best model fit of the data. TCEQ's concerns with the 
EPA's URE derivation have not been peer reviewed and the public comment 
period closed on September 26, 2019.
---------------------------------------------------------------------------

    \42\ In this instance, ``URF'' is intended to be functionally 
equivalent to the EPA's unit risk estimate for ethylene oxide.
---------------------------------------------------------------------------

    Because of the robustness of the comments received and their 
relevance to this rulemaking, the Agency will consider those comments 
in the final rule for the Miscellaneous Organic Chemical Manufacturing 
source category. In this proposed rule, we are requesting any 
additional comments on the use of the 2016 updated URE for ethylene 
oxide for regulatory purposes beyond those already received for the 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. The EPA believes it is 
reasonable to assume that, allowing for the uncertainties in the URE, 
estimated risks for the Miscellaneous Organic Chemical Manufacturing 
source category could be lower, even potentially lower than the 100-in-
1 million benchmark.

[[Page 69219]]

    It is also important to note that there is considerable uncertainty 
regarding the estimated equipment leak emissions that are responsible 
for the remaining modeled risk. As described previously in section 
IV.C.2 and summarized here, the estimated ethylene oxide equipment leak 
emissions are based on engineering calculations, not actual measured 
emissions, and, therefore, it is uncertain whether the proposed 
controls are appropriate for the actual source(s) of fugitive emissions 
at these facilities. Furthermore, at Lanxess Corporation, a 
conservatively high equipment leak emissions estimate was used, and at 
Huntsman Performance, equipment leak emissions are also thought to be 
overestimated due to knowledge that the modeled emissions are not 
entirely from MON equipment. Due to these emissions uncertainties, the 
post-control MIRs of 300-in-1 million at Huntsman Performance and 200-
in-1 million at Lanxess Corporation are likely biased high; the actual 
MIRs would be expected to be lower at both facilities. Given that the 
number of people estimated to have a cancer risk greater than 100-in-1 
million would be reduced from 18,000 to 300, the incidence would be 
reduced from 0.4 to 0.1, and considering that the MIR is expected to be 
lower than 300-in-1 million, we propose that, after application of the 
ethylene oxide-specific controls for process vents, storage tanks, and 
equipment leak co-proposed Control Option 1, risks would be acceptable.
    Alternatively, additional equipment leak controls (e.g., beyond 
equipment leak co-proposed Control Option 1) could be applied to the 
two highest risk facilities to further reduce risks. After application 
of the ethylene oxide-specific controls for process vents, storage 
tanks, and equipment leak co-proposed Control Option 2, ethylene oxide 
emissions would be reduced by 94-percent for the source category, the 
estimated MIR would be reduced from 2,000-in-1 million to 200-in-1 
million at Huntsman Performance and 100-in-1 million at Lanxess 
Corporation, the number of people estimated to have a cancer risk 
greater than 100-in-1 million would be reduced from 18,000 to 30, and 
the incidence would be reduced from 0.4 to 0.1.
    Finally, we note that the proposed control measures provide for a 
significant risk reduction. 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, the 
remaining risk is 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.
    In summary, 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, and considering all of the health risk 
information and factors discussed above, including the 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 updated URE for ethylene oxide (which is developed to be health 
protective but, given uncertainties in the value, could be as much as 5 
times lower), the EPA proposes that the resulting risks would be 
acceptable for this source category. We are soliciting 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.
4. Ample Margin of Safety Analysis
    The second step in the residual risk decision framework is 
determination of whether the emission standards proposed to achieve an 
acceptable risk level would protect public health with an ample margin 
of safety, or whether more stringent emission standards would be 
required. In making this determination, we considered the estimate of 
health risk and other health information, along with additional factors 
relating to the appropriate level of control, including costs and 
economic impacts of controls, technological feasibility, uncertainties, 
and other relevant factors, consistent with the approach of the 1989 
Benzene NESHAP. Table 8 of this preamble presents the summary of costs 
and ethylene oxide emission reductions we estimated for the proposed 
control options. For details on the assumptions and methodologies used 
in the costs and impacts analyses, see the technical memoranda titled 
Analysis of Control Options for Storage Tanks and Process Vents 
Emitting Ethylene Oxide Located in the Miscellaneous Organic Chemical 
Manufacturing Source Category and Analysis of Control Options for 
Equipment Leaks at Processes that use Ethylene Oxide Located in the 
Miscellaneous Organic Chemical Manufacturing Source Category, which are 
available in the docket for this rulemaking.

    Table 8--Nationwide Emission Reductions and Cost Impacts of Control Options Considered for Process Vents,
                        Storage Tanks, and Equipment in Ethylene Oxide (EtO) Service \1\
----------------------------------------------------------------------------------------------------------------
                                                                                                       Cost
                                                   Total capital       Total       EtO emission    effectiveness
                 Control option                     investment      annualized      reductions      ($/ton EtO)
                                                        ($)        costs  ($/yr)     (tpy) \2\          \3\
----------------------------------------------------------------------------------------------------------------
A--Process Vent Controls........................       2,180,000         914,000             1.2         783,000
B--Storage Tank Controls........................         466,000         796,000             8.6          93,100
C--Equipment Leak co-proposed Control Option 1..          76,000          48,000             3.6          13,200
                                                 ---------------------------------------------------------------
    Total (A + B + C)...........................       2,720,000       1,760,000            13.3         132,000
D--Equipment Leak co-proposed Control Option 2..         673,000         148,000             4.5          33,000
                                                 ---------------------------------------------------------------
    Total (A + B + D)...........................       3,320,000       1,860,000            14.2         131,000
----------------------------------------------------------------------------------------------------------------
\1\ Costs are calculated for the year 2016 and assume that a scrubber was installed as the control device.
\2\ Reductions shown are based on model plant emission estimates, not on emissions that were modeled in the risk
  assessment.
\3\ Cost effectiveness presented is without recovery credits, which represent the savings in product that would
  not be lost from equipment leaks.

[[Page 69220]]

    For the ample margin of safety analysis, we evaluated the cost and 
feasibility of available control technologies that could be applied in 
this source category to further reduce the risks (or potential risks) 
due to emissions of HAP, considering all of the health risks and other 
health information considered in the risk acceptability determination 
described above. We note that we did not identify any other controls 
for ethylene oxide emission sources so we are considering all the 
available options to reduce risk.
    In the case that we apply the process vent, storage tank, and 
equipment leak co-proposed Control Option 1 in the first step (i.e., 
determination of acceptable risk), we considered this option as well as 
three additional options in the second step to establish an ample 
margin of safety. For the three additional options, first, we 
considered implementing equipment leak co-proposed Control Option 2, 
which would require that the two facilities with cancer risks greater 
than 100-in-1 million comply with more stringent standards. Second, 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 
cancer risks. Third, we considered the options identified in the 
technology review (i.e., controls to equipment leaks for MON equipment 
not in ethylene oxide service and heat exchange systems). The ample 
margin of safety analysis for these options is discussed below.
    First, in the case of implementing the ethylene oxide equipment 
leak co-proposed Control Option 2, we compared the costs of co-proposed 
Control Option 1 to co-proposed Control Option 2 ($76,000 vs. $673,000 
total capital investment; $48,000 vs. $148,000 total annualized cost). 
From the ethylene oxide equipment leak co-proposed Option 1 to Option 
2, the MIR would be reduced from 300-in-1 million to 200-in-1 million, 
the population exposed to cancer risks >=1-in-1 million would be 
reduced from 2,300,000 to 2,100,000, and the incidence would remain 
unchanged at 0.1.
    Second, in the case that we expand 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, 
costs were also found to be considerably higher compared to ethylene 
oxide equipment leak co-proposed Control Option 1 ($76,000 vs. 
$1,600,000 total capital investment; $48,000 vs. $300,000 total 
annualized cost). The estimated ethylene oxide emissions reductions are 
5.8 tons per year with a cost effectiveness of $51,000 per ton of 
ethylene oxide. The population exposed to cancer risks greater than or 
equal to 1-in-1 million would be reduced by 14,000, but there are no 
additional reductions in the MIR or incidence when expanding these more 
stringent standards to apply to all facilities with equipment in 
ethylene oxide service. We solicit comment on whether we should apply 
the requirements of equipment leak co-proposed Control Option 2 that 
are specific to the two highest risk facilities more broadly, so that 
they apply to all facilities with equipment in ethylene oxide service.
    Third, we considered control options identified in the technology 
review (section IV.D of this preamble), which apply to all HAP and are 
not specific to ethylene oxide. These options include controls for (1) 
equipment leaks for MON equipment not in ethylene oxide service 
(options 1 through 4), and (2) heat exchangers. For controls for 
equipment leaks for MON equipment not in ethylene oxide service (option 
1, described in section IV.D.1 of this preamble) and heat exchangers, 
while cost-effective, neither lowered the source category MIR, 
incidence, or population exposed to cancer risks >=1-in-1 million. For 
equipment leak controls for MON equipment not in ethylene oxide 
service, options 2, 3, and 4 (described in section IV.D.1 of this 
preamble) were not cost-effective and did not reduce the source 
category MIR, incidence, or population exposed to risks >=1-in-1 
million, with the exception of the equipment leak option 3 controls 
which lowered the population exposed to cancer risks >=1-in-1 million 
by approximately 250,000 people.
    Based on our ample margin of safety analysis, including all health 
information and the associated cost and feasibility as discussed above, 
we propose that the requirements that we are proposing to achieve 
acceptable risks would also provide an ample margin of safety to 
protect public health. We are soliciting comment on which of the 
available control options should be applied in order to provide an 
ample margin of safety to protect public health.
5. Adverse Environmental Effects
    We do not expect there to be an adverse environmental effect as a 
result of HAP emissions from this source category, and we are proposing 
that it is not necessary to set a more stringent standard to prevent, 
taking into consideration costs, energy, safety, and other relevant 
factors, an adverse environmental effect.

D. What are the results and proposed decisions based on our technology 
review?

    Sources of HAP emissions regulated by the MON are process vents, 
storage tanks, transfer racks, equipment leaks, wastewater streams, and 
heat exchange systems. MON processes can either be batch or continuous 
operations. Batch operations mean a non-continuous operation involving 
intermittent or discontinuous feed into equipment and, in general, 
involve the emptying of the equipment after the operation ceases and 
prior to beginning a new operation. To inform our technology reviews 
for these emissions sources, we reviewed the EPA's Reasonably Available 
Control Technology/Best Available Control Technology/Lowest Achievable 
Emission Rate (RACT/BACT/LAER) clearinghouse and regulatory development 
efforts published after the MON for similar sources. (See the 
memorandum titled Review of the RACT/BACT/LAER Clearinghouse Database 
for the Miscellaneous Organic Chemical Manufacturing Source Category, 
which is available in the docket for this rulemaking.) After reviewing 
information from the afore-mentioned sources, we have identified 
certain developments in practices, processes, or control technologies 
to reduce emissions from some of the sources of HAP emissions regulated 
by the MON. We then evaluated the impacts of applying these 
developments to the Miscellaneous Organic Chemical Manufacturing source 
category and are proposing revisions to the MON for equipment leaks and 
heat exchange systems pursuant to CAA section 112(d)(6).
1. Equipment Leaks
    Emissions of HAP (e.g., beyond ethylene oxide) from equipment leaks 
occur in the form of gases or liquids that escape to the atmosphere 
through many types of connection points (e.g., threaded fittings) or 
through the moving parts of certain types of process equipment during 
normal operation. Equipment regulated by the MON includes pumps, 
compressors, agitators, PRDs, sampling collection systems, open-ended 
valves or lines, valves, connectors, and instrumentation systems that 
contain or contact material that is 5 percent by weight or more of 
organic HAP, operate 300 hours per year or more, and are not in vacuum 
service.
    Depending on the type of equipment, the equipment leak requirements 
of the MON provide the option of meeting the

[[Page 69221]]

control requirements of 40 CFR part 63, subparts H (National Emission 
Standards for Organic Hazardous Air Pollutants for Equipment Leaks), or 
UU (National Emission Standards for Equipment Leaks--Control Level 2 
Standards), or 40 CFR part 65, subpart F (the Consolidated Air Rule for 
Equipment Leaks) for existing MON processes and 40 CFR part 63, subpart 
UU, or 40 CFR part 65, subpart F, for new MON processes. The equipment 
leak requirements vary by equipment (component) type but require LDAR 
using monitoring with EPA Method 21 of appendix A-7 to 40 CFR part 60 
at certain frequencies (e.g., monthly, quarterly, every 2 quarters, 
annually) and leak definitions (e.g., 500 ppm, 1,000 ppm, 10,000 ppm) 
if the component is in either gas and vapor service or in light liquid 
service. The LDAR requirements for components in heavy liquid service 
require sensory monitoring and the use of EPA Method 21 monitoring if a 
leak is identified.
    The practices, processes, and control technologies considered 
during MACT development for equipment leaks at MON facilities included 
LDAR. To identify developments for the technology review, we reviewed 
the control options that were considered for the proposed MON in 2003. 
As mentioned previously in section IV.C.2 of this preamble, the EPA 
conducted a general analysis in the 2011 equipment leaks study \43\ to 
identify the latest developments in practices, processes, and control 
technologies for equipment leaks at chemical manufacturing facilities 
and petroleum refineries and estimated the impacts of applying those 
practices, processes, and control technologies to model facilities. We 
also used this 2011 equipment leaks analysis as a reference for 
conducting the technology review for equipment leaks at MON facilities. 
Additionally, we evaluated other federal regulations (i.e., the 
finalized Petroleum Refinery Sector MACT,\44\ NSPS subpart VVa,\45\ and 
the Hazardous Organic NESHAP \46\) and state regulations (e.g., the 
Texas fugitive emissions rules applicable to petrochemical processes 
47 48) as part of this review.
---------------------------------------------------------------------------

    \43\ Hancy. 2011. Memorandum from Hancy, C., RTI International 
to Howard, J., EPA/OAQPS. Analysis of Emissions Reduction Techniques 
for Equipment Leaks. December 21, 2011. EPA Docket ID No. EPA-HQ-
OAR-2010-0869.
    \44\ 40 CFR part 63, subpart CC: National Emission Standards for 
Organic Hazardous Air Pollutants from Petroleum Refineries.
    \45\ 40 CFR part 60, subpart VVa: Standards of Performance for 
Equipment Leaks of VOC in the Synthetic Organic Chemicals 
Manufacturing Industry for Which Construction, Reconstructions, or 
Modification Commenced After November 7, 2006.
    \46\ 40 CFR part 63, subpart H: National Emission Standards for 
Organic Hazardous Air Pollutants for Equipment Leaks.
    \47\ 30 TAC 115, subchapter D, Division 3: Control of Air 
Pollution from Volatile Organic Compounds; Petroleum Refining, 
Natural Gas Processing, and Petrochemical Processes; Fugitive 
Emission Control in Petroleum Refining, Natural Gas/Gasoline 
Processing, and Petrochemical Processes in Ozone Nonattainment 
Areas.
    \48\ 30 TAC 115, subchapter H, Division 3: Control of Air 
Pollution from Volatile Organic Compounds; Highly-Reactive Volatile 
Organic Compounds; Fugitive Emissions (referred to as the TX HRVOC 
rule).
---------------------------------------------------------------------------

    Our technology review for equipment leaks of HAP (e.g., beyond 
ethylene oxide) identified several developments in LDAR practices and 
processes: Option 1, lowering the leak definition for pumps in light 
liquid service at existing batch processes from 10,000 ppm to 1,000 ppm 
with monthly monitoring; option 2, lowering the leak definition for 
pumps in light liquid service at existing batch processes from 10,000 
ppm to 500 ppm and at existing continuous processes from 1,000 ppm to 
500 ppm with monthly monitoring; option 3, requiring monitoring of 
connectors in gas and vapor service or light liquid service at a leak 
definition of 500 ppm with monitoring every 8 years; and option 4, 
lowering the leak definition for valves in gas and vapor service or 
light liquid service from 500 ppm to 100 ppm at both batch and 
continuous processes with quarterly monitoring. For all other component 
types, we did not identify developments in LDAR practices and 
processes.
    Emissions reductions were estimated for the new developments that 
we identified using component counts and emission factors. The 
component counts were derived using data from the original MON rule, 
which included model component counts for 224 facilities, with 167 
using batch processes, 57 using continuous processes, and three not 
having information. The batch facilities contained 1,049 batch 
processes, or an average of 6.3 per facility. The continuous facilities 
contained 88 continuous processes, or an average of 1.5 per facility. 
These values were scaled to estimate the number of batch and continuous 
processes for the current count of 201 facilities, resulting in 943 
batch processes and 79 continuous processes nationwide. The number of 
nationwide processes was then multiplied by the component counts to 
estimate the nationwide component counts. Subsequently, baseline 
emissions and emissions after implementation of the controls for each 
component were calculated for continuous and batch processes using the 
nationwide component counts for continuous and batch processes derived 
from the 2003 MON analysis and emission factors and leak frequencies 
for the chemical manufacturing industry from the 2011 equipment leaks 
study.\49\
---------------------------------------------------------------------------

    \49\ Hancy. 2011. Memorandum from Hancy, C., RTI International 
to Howard, J., EPA/OAQPS. Analysis of Emissions Reduction Techniques 
for Equipment Leaks. December 21, 2011. EPA Docket ID No. EPA-HQ-
OAR-2010-0869.
---------------------------------------------------------------------------

    Costs were then calculated for the baseline and control options, 
which reflect the cost to implement an LDAR program for each component. 
Note that the difference between the costs for the baseline and control 
options is the incremental cost to comply with the controls. Costs were 
calculated for the year 2016, and capital costs were annualized using a 
5-percent interest rate. Furthermore, because the control options 
result in chemicals in process lines not leaking and, therefore, not 
being lost, we present costs both with and without this consideration. 
To estimate savings in chemicals not being emitted (i.e., lost) due to 
the equipment leak control options, we applied a recovery credit of 
$900 per ton of VOC to the VOC emission reductions in the analyses. The 
$900 per ton recovery credit has historically been used by the EPA to 
represent the variety of chemicals that are used as reactants and 
produced at synthetic organic chemical manufacturing facilities,\50\ 
however, we recognize that this value is from a 2007 analysis and may 
be outdated. Therefore, we solicit comment on the availability of more 
recent information to potentially update the value used in this 
analysis to estimate the recovery credits. The complete cost 
calculation methodology is documented in 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.
---------------------------------------------------------------------------

    \50\ U.S. EPA. 2007. Standards of Performance for Equipment 
Leaks of VOC in the Synthetic Organic Chemicals Manufacturing 
Industry; Standards of Performance for Equipment Leaks of VOC in 
Petroleum Refineries (https://www.federalregister.gov/documents/2007/07/09/E7-13203/standards-of-performance-for-equipment-leaks-of-voc-in-the-synthetic-organic-chemicals-manufacturing). EPA-HQ-OAR-
2006-0699.
---------------------------------------------------------------------------

    We calculated the VOC and HAP cost effectiveness by dividing the 
incremental annual costs by the emissions reductions. Table 9 of this 
preamble presents the nationwide costs and impacts for the suite of 
equipment leak control options considered. See the technical memorandum 
titled Clean Air Act Section 112(d)(6) Technology

[[Page 69222]]

Review for Equipment Leaks Located in the Miscellaneous Organic 
Chemical Manufacturing Source Category, which is available in the 
docket for this rulemaking, for details on the assumptions and 
methodologies used in this analysis.
    Based on the costs and emission reductions for each of the options, 
we determined that option 1 is a cost-effective strategy for further 
reducing HAP emissions from equipment leaks from MON equipment not in 
ethylene oxide service, and we are proposing at 40 CFR 63.2480(b)(6) 
and (c)(10) to revise the MON for equipment leaks 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, 
pursuant to CAA section 112(d)(6). We are also clarifying at 40 CFR 
63.2480(b)(7) and (c)(11) that you must initially monitor for leaks 
within 30 days after initial startup of the equipment. We solicit 
comment on these proposed revisions. Considering the high cost per ton 
estimate, we determined that equipment leak options 2, 3, and 4 are not 
cost effective for the entire source category; therefore, we are not 
proposing to revise the MON to reflect the requirements of these 
options pursuant to CAA section 112(d)(6).

                 Table 9--Nationwide Emissions Reduction and Cost Impacts of Control Options Considered for Equipment Leaks for MON Equipment Not in Ethylene Oxide Service \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Total         Total
                                                                    Total      annualized    annualized        VOC           HAP         VOC cost       VOC cost       HAP cost       HAP cost
                        Control  option                            capital      costs w/o    costs with     emission      emission    effectiveness  effectiveness  effectiveness  effectiveness
                                                                 investment    credits \2\   credits \2\   reductions    reductions     w/o credits   with credits    w/o credits   with credits
                                                                     ($)         ($/yr)        ($/yr)         (tpy)         (tpy)      \2\ ($/ton)    \2\ ($/ton)    \2\ ($/ton)    \2\ ($/ton)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1.............................................................       863,100       156,600        85,200          79.3          7.93          1,980          1,075         19,760         10,760
2.............................................................     1,416,800       303,000       223,900          87.9          8.79          3,450          2,550         34,480         25,480
3.............................................................     9,326,800     1,381,900       910,600           524          52.4          2,640          1,740         26,390         17,390
4.............................................................       650,800       116,300        93,300          25.5          2.55          4,560          3,660         45,630         36,630
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Costs are calculated for the year 2016.
\2\ Recovery credits represent the cost savings in chemicals not being emitted (i.e., lost) due to the equipment leak options.

2. Heat Exchange Systems
    Heat exchangers are devices or collections of devices used to 
transfer heat from process fluids to another process fluid (typically 
water) without intentional direct contact of the process fluid with the 
cooling fluid (i.e., non-contact heat exchanger). There are two types 
of heat exchange systems: Closed-loop recirculation systems and once-
through systems. Closed-loop recirculation systems use a cooling tower 
to cool the heated water leaving the heat exchanger and then return the 
newly cooled water to the heat exchanger for reuse. Once-through 
systems typically use surface freshwater (e.g., from rivers) as the 
influent cooling fluid to the heat exchangers, and the heated water 
leaving the heat exchangers is then discharged from the facility. At 
times, the internal tubing material of a heat exchanger can corrode or 
crack, allowing some process fluids to mix or become entrained with the 
cooling water. Pollutants in the process fluids may subsequently be 
released from the cooling water into the atmosphere when the water is 
exposed to air (e.g., in a cooling tower for closed-loop systems or 
trenches/ponds in a once-through system). The term ``heat exchange 
system'' is not defined in the MON; therefore, we are proposing a 
definition for this term at 40 CFR 63.2550(i) that would apply only to 
the MON standards. We are proposing to define ``heat exchange system'' 
as 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, 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, 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 proposed definition and are not part of the heat exchange 
system. Intentional direct contact with process fluids results in the 
formation of a wastewater.
    The MON includes an LDAR program for owners or operators of certain 
heat exchange systems which meets the requirements of 40 CFR 63.104 
(National Emission Standards for Organic Hazardous Air Pollutants from 
the Synthetic Organic Chemical Manufacturing Industry). The LDAR 
program specifies that heat exchange systems be monitored for leaks of 
process fluids into cooling water and that owners or operators take 
actions to repair detected leaks within 45 days. Owners or operators 
may delay the repair of leaks if they meet the applicable criteria in 
40 CFR 63.104. The current MON, for heat exchange systems, allows the 
use of any method listed in 40 CFR part 136 for sampling cooling water 
for leaks for the HAP listed in Table 4 to 40 CFR part 63, subpart F, 
for recirculating systems and Table 9 to 40 CFR part 63, subpart G for 
once-through systems. A leak in the heat exchange system is detected if 
the exit mean concentration of HAP (or other representative substance) 
in the cooling water is at least 1 ppmw or 10 percent greater than 
(using a one-sided statistical procedure at the 0.05 level of 
significance) the entrance mean concentration of HAP (or other 
representative substance) in the cooling water. Furthermore, the MON 
allows owners or operators to monitor for leaks using a surrogate 
indicator of leaks (e.g., ion-specific electrode monitoring, pH, 
conductivity), provided that certain criteria in 40 CFR 63.104(c) are 
met. The MON initially requires 6 months of monthly monitoring for 
existing heat exchange systems. Thereafter, the frequency can be 
reduced to quarterly. The leak monitoring frequencies are the same 
whether water sampling and analysis or surrogate monitoring is used to 
identify leaks.
    Our technology review identified one development in LDAR practices 
and processes for heat exchange systems, the

[[Page 69223]]

use of the Modified El Paso Method \51\ to monitor for leaks. The 
Modified El Paso Method, which is included in the Petroleum Refinery 
Sector rule (i.e., 40 CFR part 63, subpart CC), was identified in our 
review of the RACT/BACT/LAER clearinghouse database. It is also 
required by the TCEQ for facilities complying with their HRVOC rule 
(i.e., 30 TAC Chapter 115, Subchapter H, Division 3). The Modified El 
Paso Method measures a larger number of compounds than the current 
methods required in the MON and is more effective in identifying leaks. 
For heat exchange system LDAR programs, the compliance monitoring 
option, leak definition, and frequency of monitoring for leaks are all 
important considerations affecting emission reductions by identifying 
when there is a leak and when to take corrective actions to repair the 
leak. Therefore, we evaluated the Modified El Paso Method for use at 
MON facilities, including an assessment of appropriate leak definitions 
and monitoring frequencies.
---------------------------------------------------------------------------

    \51\ 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 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.
---------------------------------------------------------------------------

    In order to identify an appropriate Modified El Paso Method leak 
definition for MON facilities, we identified two rules, TCEQ's HRVOC 
rule and the Petroleum Refinery Sector rule, both of which incorporate 
this monitoring method and have leak definitions corresponding to the 
use of this methodology. We also reviewed data submitted in response to 
a CAA section 114 request for the Ethylene Production RTR where 
facilities performed sampling using the Modified El Paso Method.
    The Petroleum Refinery Sector rule and TCEQ's HRVOC rule have leak 
definitions of total strippable hydrocarbon concentration (as methane) 
in the stripping gas ranging from 3.1 ppmv to 6.2 ppmv. In addition, 
sources subject to the Petroleum Refinery Sector rule may not delay the 
repair of leaks for more than 30 days where, during subsequent 
monitoring, a total strippable hydrocarbon concentration (as methane) 
in the stripping gas of 62 ppmv or higher is found. In reviewing the 
Ethylene Production RTR CAA section 114 data, a clear delineation in 
the hydrocarbon mass emissions data was noticed at 6.1 ppmv of total 
strippable hydrocarbon (as methane) in the stripping gas. In addition, 
given that both the leak concentration and water recirculation rate of 
the heat exchange system are key variables affecting the hydrocarbon 
mass emissions from heat exchange systems, the overall Ethylene 
Production RTR CAA section 114 data for all heat exchange systems 
sampled generally showed lower hydrocarbon mass emissions for leaks at 
or below 6.1 ppmv of total strippable hydrocarbon (as methane) in the 
stripping gas compared to leaks found above 6.1 ppmv of total 
strippable hydrocarbon (as methane) in the stripping gas. Taking into 
account the range of actionable leak definitions in use by other rules 
that require use of the Modified El Paso Method currently (i.e., 3.1 
ppmv-6.2 ppmv of total strippable hydrocarbon (as methane) in the 
stripping gas), and the magnitude of emissions for leaks of total 
strippable hydrocarbon (as methane) in the stripping gas above 6.1 ppmv 
compared to other leaks identified in the CAA section 114 sampling 
data, we chose to evaluate a leak definition at the upper end of 
identified actionable leak definitions in our analysis. Thus, the 
Modified El Paso Method leak definition we evaluated was 6.2 ppmv of 
total strippable hydrocarbon concentration (as methane) in the 
stripping gas for both new and existing heat exchange systems, along 
with not allowing delay of repair of leaks for more than 30 days where, 
during subsequent monitoring, a total strippable hydrocarbon 
concentration (as methane) in the stripping gas of 62 ppmv or higher is 
found.
    We determined an appropriate leak monitoring frequency by reviewing 
the current monitoring frequencies that MON facilities are subject to, 
along with frequencies for the Petroleum Refinery Sector rule and the 
TCEQ HRVOC rule, and information gathered in the Ethylene Production 
RTR CAA section 114 survey. As a first step, we reviewed whether it was 
still reasonable to specify more frequent monitoring for a 6-month 
period after repair of leaks. Our review of the Ethylene Production RTR 
CAA section 114 data showed that no leaks were identified during the 6-
month period post repair for any of the facilities that reported heat 
exchange system compliance data that had leaks. Thus, we find that re-
monitoring once after repair of a leak, at the monitoring location 
where the leak was identified, is sufficient from a continuous 
compliance perspective to demonstrate a successful repair. The 
monitoring frequencies currently required by MON for where no leaks are 
found were, thus, considered the base frequencies (i.e., quarterly 
monitoring for existing and new heat exchange systems). Once we 
determined the base frequencies, we next considered more stringent 
monitoring frequencies. Both the Petroleum Refinery Sector rule, which 
includes monthly monitoring for existing sources, under certain 
circumstances, and the TCEQ HRVOC rule, which includes continuous 
monitoring provisions for existing and new sources, have more stringent 
monitoring frequencies. However, the incremental HAP cost effectiveness 
to change from quarterly to monthly monitoring and monthly to 
continuous monitoring was found to be $40,000/ton and $500,000/ton, 
respectively. We conclude that these costs are not reasonable for MON 
facilities. Thus, we chose to evaluate quarterly monitoring for 
existing and new heat exchange systems (i.e., the base monitoring 
frequency currently in the rule).
    Based on this technology review, we identified the following 
control option for heat exchanger systems as a development in practice 
that can be implemented at a reasonable cost: Quarterly monitoring for 
existing and new heat exchange systems (after an initial 6 months of 
monthly monitoring) with the Modified El Paso Method and a leak 
definition of 6.2 ppmv of total strippable hydrocarbon concentration 
(as methane) in the stripping gas.
    We then estimated the impacts of this control option assuming that 
all 201 MON facilities would be affected by requiring the use of the 
Modified El Paso Method. As part of our analysis, we assumed owners or 
operators conducting quarterly monitoring for three or more of these 
heat exchange systems would elect to purchase a stripping column and 
FID analyzer and perform in-house Modified El Paso monitoring (because 
the total annualized costs for in-house Modified El Paso monitoring are 
less than the costs for contracted services). In addition, we assumed 
repairs could be performed by plugging a specific heat exchanger tube, 
and if a heat exchanger is leaking to the extent that it needs to be 
replaced, then it is effectively at the end of its useful life. 
Therefore, we determined that the cost of replacing a heat exchanger is 
an operational cost that would be incurred by the facility as a result 
of routine maintenance and equipment replacement, and it is not 
attributable to the control option.
    Table 10 of this preamble presents the nationwide impacts for 
requiring 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

[[Page 69224]]

ppmv or greater. See the technical memorandum titled 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, for details on 
the assumptions and methodologies used in this analysis.
    Based on the costs and emission reductions for the identified 
control option, we are proposing to revise the MON for heat exchange 
systems pursuant to CAA section 112(d)(6). We are proposing at 40 CFR 
63.2490(d)(1) to specify quarterly monitoring for existing and new heat 
exchange systems (after an initial 6 months of monthly monitoring) 
using the Modified El Paso Method and a leak definition of 6.2 ppmv of 
total strippable hydrocarbon concentration (as methane) in the 
stripping gas. We are also proposing at 40 CFR 63.2490(d)(4) a delay of 
repair action level of total strippable hydrocarbon concentration (as 
methane) in the stripping gas of 62 ppmv, that if exceeded during leak 
monitoring, would require immediate repair (i.e., the leak found cannot 
be put on delay of repair and would be required to be repaired within 
30 days of the monitoring event). This would apply to both monitoring 
heat exchange systems and individual heat exchangers by replacing the 
use of any 40 CFR part 136 water sampling method with the Modified El 
Paso Method and removing the option that allows for use of a surrogate 
indicator of leaks. We are also proposing at 40 CFR 63.2490(d)(2) and 
(3) re-monitoring at the monitoring location where a leak is identified 
to ensure that any leaks found are fixed. Finally, we are proposing 
that none of these proposed requirements would apply to heat exchange 
systems that have a maximum cooling water flow rate of 10 gallons per 
minute or less. We solicit comment on the proposed requirements.

   Table 10--Nationwide Emissions Reductions and Cost Impact for Requiring the Modified El Paso Method for Heat Exchange Systems at MON Facilities \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Total                                                           Total
                                                            annualized     VOC emission    HAP emission      HAP cost       annualized       HAP cost
             Control option                Total capital     costs w/o      reductions      reductions     effectiveness    costs with     effectiveness
                                          investment ($)  credits \2\ ($/      (tpy)           (tpy)        w/o credits   credits \2\ ($/  with credits
                                                                yr)                                         \2\ ($/ton)         yr)         \2\ ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.......................................       1,483,000         261,000             306              31           8,530        (14,000)           (470)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Costs are calculated for the year 2016.
\2\ Recovery credits represent the cost savings of chemicals in process lines not leaking into heat exchange systems and, therefore, not being lost, due
  to application of the El Paso Method.

3. Process Vents, Storage Tanks, Transfer Racks, Wastewater
    We did not identify any cost-effective developments in practices, 
processes, or control technologies for process vents, storage tanks, 
transfer racks, and waste streams that achieve a greater HAP emission 
reduction beyond the emission reduction already required by MON, with 
the exception of developments presented in section IV.C of this 
preamble to specifically control ethylene oxide emissions from process 
vents and storage tanks. Therefore, we are not proposing any changes to 
the NESHAP for these emission process groups based on our technology 
review. For further details on the assumptions and methodologies used 
in these analyses, see the technical memoranda titled 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.

E. What other actions are we proposing?

    In addition to the proposed actions described above, we are 
proposing additional revisions to the NESHAP. We are proposing 
revisions to the SSM provisions of the MACT rule in order to ensure 
that they are consistent with the Court decision in Sierra Club v. EPA, 
551 F.3d 1019 (D.C. Cir. 2008), which vacated two provisions that 
exempted sources from the requirement to comply with otherwise 
applicable CAA section 112(d) emission standards during periods of SSM. 
We also are proposing revisions to require electronic reporting of 
emissions test results and to clarify text or correct typographical 
errors, grammatical errors, and cross-reference errors. Our analyses 
and proposed changes related to these issues are discussed below.
1. SSM Requirements
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), the Court vacated portions of two provisions in the EPA's 
CAA section 112 regulations governing the emissions of HAP during 
periods of SSM. Specifically, the Court vacated the SSM exemption 
contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that 
under section 302(k) of the CAA, emissions standards or limitations 
must be continuous in nature and that the SSM exemption violates the 
CAA's requirement that some CAA section 112 standards apply 
continuously.
    We are proposing the elimination of the SSM exemption in this rule 
which appears at 40 CFR 63.2450(a). Consistent with Sierra Club v. EPA, 
we are proposing standards in this rule that apply at all times. We are 
also proposing several revisions to Table 12 (the General Provisions 
Applicability Table) as is explained in more detail below. For example, 
we are proposing to eliminate the incorporation of the General 
Provisions' requirement that the source develop an SSM plan. We also 
are proposing to eliminate and revise certain recordkeeping and 
reporting requirements related to the SSM exemption as further 
described below. In addition, we are proposing to make the portion of 
the ``deviation'' definition in 40 CFR 63.2550(i) that specifically 
addresses SSM periods no longer applicable beginning 3 years after 
publication of the final rule in the Federal Register. Finally, we are 
proposing at 40 CFR 63.2450(e)(4), 40 CFR 63.2480(f), and 40 CFR 
63.2485(p) and (q) to make references that are related to an SSM 
exemption in 40 CFR part 63, subpart G (for wastewater), 40 CFR part 
63, subpart SS (for process vents, storage tanks, transfer racks), and 
40 CFR part 63, subparts H and UU, and 40 CFR part 65, subpart F (for 
equipment leaks), will no longer be applicable.
    The EPA has attempted to ensure that the provisions we are 
proposing to eliminate are inappropriate, unnecessary, or redundant in 
the absence of the SSM exemption. We are specifically seeking comment 
on whether we have successfully done so.

[[Page 69225]]

    We are proposing that emissions from startup and shutdown 
activities be included when determining if all the standards are being 
attained. As currently proposed in 40 CFR 63.2450(a)(2), compliance 
with the emission limitations (including operating limits) in this 
subpart is required ``at all times.'' We solicit comment on whether 
owners and operators in the Miscellaneous Organic Chemical 
Manufacturing source category will be able to comply with the standards 
during these times. Emission reductions for process vents and transfer 
rack operations are typically achieved by routing vapors to an APCD 
such as a flare, thermal oxidizer, or carbon adsorber. It is common 
practice in this source category to start an APCD prior to startup of 
the emissions source it is controlling, so the APCD would be operating 
before emissions are routed to it. We expect APCDs would be operating 
during startup and shutdown events in a manner consistent with normal 
operating periods, and that these APCDs will be operated to maintain 
and meet the monitoring parameter operating limits set during the 
performance test.
    Periods of startup, normal operations, and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead they are, by 
definition, sudden, infrequent, and not reasonably preventable failures 
of emissions control, process, or monitoring equipment (40 CFR 63.2) 
(Definition of malfunction). 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 and this reading 
has been upheld as reasonable by the Court in U.S. Sugar Corp. v. EPA, 
830 F.3d 579, 606-610 (2016). Under CAA section 112, emissions 
standards for new sources must be no less stringent than the level 
``achieved'' by the best controlled similar source and for existing 
sources generally must be no less stringent than the average emission 
limitation ``achieved'' by the best performing 12 percent of sources in 
the category. There is nothing in CAA section 112 that directs the 
Agency to consider malfunctions in determining the level ``achieved'' 
by the best performing sources when setting emission standards. As the 
Court has recognized, the phrase ``average emissions limitation 
achieved by the best performing 12 percent of'' sources ``says nothing 
about how the performance of the best units is to be calculated.'' 
Nat'l Ass'n of Clean Water Agencies v. EPA, 734 F.3d 1115, 1141 (D.C. 
Cir. 2013). While the EPA accounts for variability in setting emissions 
standards, nothing in CAA section 112 requires the Agency to consider 
malfunctions as part of that analysis. The EPA is not required to treat 
a malfunction in the same manner as the type of variation in 
performance that occurs during routine operations of a source.
    As the Court recognized in U.S. Sugar Corp., accounting for 
malfunctions in setting standards would be difficult, if not 
impossible, given the myriad different types of malfunctions that can 
occur across all sources in the category and given the difficulties 
associated with predicting or accounting for the frequency, degree, and 
duration of various malfunctions that might occur. Id. at 608 (``the 
EPA would have to conceive of a standard that could apply equally to 
the wide range of possible boiler malfunctions, ranging from an 
explosion to minor mechanical defects. Any possible standard is likely 
to be hopelessly generic to govern such a wide array of 
circumstances.''). As such, the performance of units that are 
malfunctioning is not ``reasonably'' foreseeable. See, e.g., Sierra 
Club v. EPA, 167 F.3d 658, 662 (D.C. Cir. 1999) (``The EPA typically 
has wide latitude in determining the extent of data-gathering necessary 
to solve a problem. We generally defer to an agency's decision to 
proceed on the basis of imperfect scientific information, rather than 
to 'invest the resources to conduct the perfect study.' ''). See also, 
Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) (``In the 
nature of things, no general limit, individual permit, or even any 
upset provision can anticipate all upset situations. After a certain 
point, the transgression of regulatory limits caused by `uncontrollable 
acts of third parties,' such as strikes, sabotage, operator 
intoxication or insanity, and a variety of other eventualities, must be 
a matter for the administrative exercise of case-by-case enforcement 
discretion, not for specification in advance by regulation.''). In 
addition, emissions during a malfunction event can be significantly 
higher than emissions at any other time of source operation. For 
example, if an APCD with 99-percent removal goes off-line as a result 
of a malfunction (as might happen if, for example, the bags in a 
baghouse catch fire) and the emission unit is a steady state type unit 
that would take days to shut down, the source would go from 99-percent 
control to zero control until the control device was repaired. The 
source's emissions during the malfunction would be 100 times higher 
than during normal operations. As such, the emissions over a 4-day 
malfunction period would exceed the annual emissions of the source 
during normal operations. As this example illustrates, accounting for 
malfunctions could lead to standards that are not reflective of (and 
significantly less stringent than) levels that are achieved by a well-
performing non-malfunctioning source. It is reasonable to interpret CAA 
section 112 to avoid such a result. The EPA's approach to malfunctions 
is consistent with CAA section 112 and is a reasonable interpretation 
of the statute.
    Although no statutory language compels the EPA to set standards for 
malfunctions, the EPA has the discretion to do so where feasible. For 
example, in the Petroleum Refinery Sector RTR, the EPA established a 
work practice standard for unique types of malfunction that result in 
releases from PRDs or emergency flaring events because the EPA had 
information to determine that such work practices reflected the level 
of control that applies to the best performers. 80 FR 75178, 75211-14 
(December 1, 2015). The EPA will consider whether circumstances warrant 
setting standards for a particular type of malfunction in the 
Miscellaneous Organic Chemical Manufacturing source category, and, if 
so, whether the EPA has sufficient information to identify the relevant 
best performing sources and establish a standard for such malfunctions. 
We also encourage commenters to provide any such information.
    In the event that a source fails to comply with the applicable CAA 
section 112(d) standards as a result of a malfunction event, the EPA 
would determine an appropriate response based on, among other things, 
the good faith efforts of the source to minimize emissions during 
malfunction periods, including preventative and corrective actions, as 
well as root cause analyses to ascertain and rectify excess emissions.
a. General Duty
    We are proposing to revise the General Provisions table (Table 12) 
entry for 40 CFR 63.6(e)(1)(i) by adding a separate row for 40 CFR 
63.6(e)(1)(i) and changing the ``yes'' in column 3 to a ``no'' in which 
40 CFR 63.6(e)(1)(i) would no longer be applicable beginning 3 years 
after publication of the final rule in the Federal Register. We are 
proposing to add general duty regulatory text at 40 CFR 63.2450(u) that 
reflects the general duty to minimize emissions ``at all times'' while

[[Page 69226]]

eliminating the reference to periods covered by an SSM exemption. The 
current language in 40 CFR 63.6(e)(1)(i) characterizes what the general 
duty entails during periods of SSM. With the elimination of the SSM 
exemption, there is no need to differentiate between normal operations, 
startup and shutdown, and malfunction events in describing the general 
duty. Therefore, the language the EPA is proposing for 40 CFR 
63.2450(u) does not include that language from 40 CFR 63.6(e)(1).
    We are also proposing to revise the General Provisions table (Table 
12) entry for 40 CFR 63.6(e)(1)(ii) by adding a separate row for 40 CFR 
63.6(e)(1)(ii) and changing the ``yes'' in column 3 to a ``no'' in 
which 40 CFR 63.6(e)(1)(ii) would no longer be applicable beginning 3 
years after publication of the final rule in the Federal Register. 
Section 63.6(e)(1)(ii) imposes requirements that are not necessary with 
the elimination of the SSM exemption or are redundant with the general 
duty requirement being added at 40 CFR 63.2450(u).
b. SSM Plan
    We are proposing to revise the General Provisions table (Table 12) 
entries for 40 CFR 63.6(e)(3)(i), (ii), (v) through (viii), and (ix) by 
changing the ``yes'' in column 3 to a ``no'' in which these provisions 
would no longer be applicable beginning 3 years after publication of 
the final rule in the Federal Register. Generally, these paragraphs 
require development of an SSM plan and specify SSM recordkeeping and 
reporting requirements related to the SSM plan. As noted, the EPA is 
proposing to remove the SSM exemptions. Therefore, affected units will 
be subject to an emission standard during such events. The 
applicability of a standard during such events will ensure that sources 
have ample incentive to plan for and achieve compliance and, thus, the 
SSM plan requirements are no longer necessary.
c. Compliance With Standards
    We are proposing to revise the General Provisions table (Table 12) 
entry for 40 CFR 63.6(f)(1) by changing the ``yes'' in column 3 to a 
``no'' in which 40 CFR 63.6(f)(1) would no longer be applicable 
beginning 3 years after publication of the final rule in the Federal 
Register. The current language of 40 CFR 63.6(f)(1) exempts sources 
from non-opacity standards during periods of SSM. As discussed above, 
the court in Sierra Club vacated the exemptions contained in this 
provision and held that the CAA requires that some CAA section 112 
standards apply continuously. Consistent with Sierra Club, the EPA is 
proposing to revise standards in this rule to apply at all times.
    We are proposing to revise the General Provisions table (Table 12) 
entry for 40 CFR 63.6(h)(1) by adding a separate row for 40 CFR 
63.6(h)(1) and changing the ``yes'' in column 3 to a ``no'' in which 40 
CFR 63.6(h)(1) would no longer be applicable beginning 3 years after 
publication of the final rule in the Federal Register. The current 
language of 40 CFR 63.6(h)(1) exempts sources from opacity standards 
during periods of SSM. As discussed above, the Court in Sierra Club 
vacated the exemptions contained in this provision and held that the 
CAA requires that some CAA section 112 standard apply continuously. 
Consistent with Sierra Club, the EPA is proposing to revise standards 
in this rule to apply at all times.
d. Performance Testing
    We are proposing to revise the General Provisions table (Table 12) 
entry for 40 CFR 63.7(e)(1) by changing the ``yes'' in column 3 to a 
``no'' in which 40 CFR 63.7(e)(1) would no longer be applicable 
beginning 3 years after publication of the final rule in the Federal 
Register. Section 63.7(e)(1) describes performance testing 
requirements. The EPA is instead proposing to add performance testing 
at 40 CFR 63.2450(g)(6). The performance testing we are proposing to 
add differs from the General Provisions performance testing provisions 
in several respects. The proposed regulatory text does not include the 
language in 40 CFR 63.7(e)(1) that restated the SSM exemption and 
language that precluded startup and shutdown periods from being 
considered ``representative'' for purposes of performance testing. The 
proposed performance testing provisions will exclude periods of startup 
or shutdown as representative conditions for conducting performance 
testing. As in 40 CFR 63.7(e)(1), performance tests conducted under 
this subpart should not be conducted during malfunctions because 
conditions during malfunctions are often not representative of normal 
operating conditions. The EPA is proposing to add language that 
requires the owner or operator to record the process information that 
is necessary to document operating conditions during the test and 
include in such record an explanation to support that such conditions 
represent normal operation. Section 63.7(e) requires that the owner or 
operator make available to the Administrator upon request such records 
``as may be necessary to determine the condition of the performance 
test,'' but does not specifically require the information to be 
recorded. The regulatory text the EPA is proposing to add to this 
provision builds on that requirement and makes explicit the requirement 
to record the information.
e. Monitoring
    We are proposing to revise the General Provisions table (Table 12) 
entries for 40 CFR 63.8(c)(1)(i) through (iii) by changing the ``yes'' 
in column 3 to a ``no'' in which these provisions would no longer be 
applicable beginning 3 years after publication of the final rule in the 
Federal Register. The cross-references to the general duty and SSM plan 
requirements in those subparagraphs are not necessary in light of other 
requirements of 40 CFR 63.8 that require good air pollution control 
practices (40 CFR 63.8(c)(1)) and that set out the requirements of a 
quality control program for monitoring equipment (40 CFR 63.8(d)).
    We are proposing to revise the General Provisions table (Table 12) 
entry for 40 CFR 63.8(d) by adding separate rows for 40 CFR 63.8(d)(1) 
through (3) and changing the ``yes'' in column 3 to a ``no'' in which 
40 CFR 63.8(d)(3) would no longer be applicable beginning 3 years after 
publication of the final rule in the Federal Register. The final 
sentence in 40 CFR 63.8(d)(3) refers to the General Provisions' SSM 
plan requirement which is no longer applicable. The EPA is proposing to 
add to the rule at 40 CFR 63.2450(j)(6) text that is identical to 40 
CFR 63.8(d)(3) except that the final sentence is replaced with the 
following sentence: ``The program of corrective action should be 
included in the plan required under Sec.  63.8(d)(2).''
f. Recordkeeping
    We are proposing to revise the General Provisions table (Table 12) 
entry for 40 CFR 63.10(b)(2)(i), (ii), (iv), and (v) by adding separate 
rows for each provision and changing the ``yes'' in column 3 to a 
``no'' in which 40 CFR 63.10(b)(2)(ii), (iv), and (v) would no longer 
be applicable beginning 3 years after publication of the final rule in 
the Federal Register. 40 CFR 63.10(b)(2)(ii) describes the 
recordkeeping requirements during a malfunction. The EPA is proposing 
to add such requirements to 40 CFR 63.2525(h) and (l). The regulatory 
text we are proposing to add differs from the General Provisions it is 
replacing in that the

[[Page 69227]]

General Provisions requires the creation and retention of a record of 
the occurrence and duration of each malfunction of process, air 
pollution control, and monitoring equipment. The EPA is proposing that 
this requirement apply to any failure to meet an applicable standard 
and is requiring that the source record the date, time, and duration of 
the failure rather than the ``occurrence.'' The EPA is also proposing 
to add to 40 CFR 63.2525(l) a provision that sources keep records that 
include a list of the affected source or equipment and actions taken to 
minimize emissions, an estimate of the quantity of each regulated 
pollutant emitted over the standard for which the source failed to meet 
the standard, and a description of the method used to estimate the 
emissions. Examples of such methods would include product-loss 
calculations, mass balance calculations, measurements when available, 
or engineering judgment based on known process parameters. The EPA is 
proposing to require that sources keep records of this information to 
ensure that there is adequate information to allow the EPA to determine 
the severity of any failure to meet a standard, and to provide data 
that may document how the source met the general duty to minimize 
emissions when the source has failed to meet an applicable standard.
    When applicable, 40 CFR 63.10(b)(2)(iv) requires sources to record 
actions taken during SSM events when actions were inconsistent with 
their SSM plan. The requirement is no longer appropriate because SSM 
plans will no longer be required. The requirement previously applicable 
under 40 CFR 63.10(b)(2)(iv)(B) to record actions to minimize emissions 
and record corrective actions is now applicable by reference to 40 CFR 
63.2525(l). Finally, when applicable, 40 CFR 63.10(b)(2)(v) requires 
sources to record actions taken during SSM events to show that actions 
taken were consistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required.
    We are proposing to revise the General Provisions table (Table 12) 
entry for 40 CFR 63.10(c)(15) by adding a separate row for this 
provision and changing column 3 to a ``no'' in which 40 CFR 
63.10(c)(15) would no longer be applicable to CEMS beginning 3 years 
after publication of the final rule in the Federal Register. When 
applicable, the provision allows an owner or operator to use the 
affected source's SSM plan or records kept to satisfy the recordkeeping 
requirements of the SSM plan, specified in 40 CFR 63.6(e), to also 
satisfy the requirements of 40 CFR 63.10(c)(10) through (12). The EPA 
is proposing to eliminate this requirement because SSM plans would no 
longer be required, and, therefore, 40 CFR 63.10(c)(15) no longer 
serves any useful purpose for affected units.
2. Monitoring, Recordkeeping, and Reporting Requirements
a. Monitoring for Adsorbers That Cannot Be Regenerated and Regenerative 
Adsorbers That Are Regenerated Offsite
    We are proposing to add 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 are proposing owners and operators of this type of APCD use 
dual adsorbent beds in series and conduct daily monitoring. We have 
prescribed a dual bed system because the use of a single bed does not 
ensure continuous compliance unless the bed is replaced significantly 
before breakthrough.\52\ A dual bed system will allow one bed to be 
saturated before it is replaced and, therefore, makes efficient use of 
the adsorber bed without exceeding the emission limits. Facilities 
utilizing non-regenerative adsorbers must typically replace the 
adsorber bed at the end of the absorbent life and already have a second 
bed onsite. Therefore, we have determined that these proposed 
requirements would not impose a cost increase; it would only require a 
second adsorber bed to be purchased earlier than it would have under 
previous rules. In addition, once the second adsorber was purchased, 
the source would need to purchase and install canisters at the same 
rate they would have under previous rules. In fact, the source could 
likely reduce costs over time because the adsorber beds can be used to 
a greater saturation level without risking non-compliance. Without the 
proposed requirement to use dual adsorbent beds in series, sources 
might replace the beds based on temperature readings, the vendor's bed 
life expectancy estimates or past history, and may replace the bed 
prematurely in order to avoid non-compliance. The burden of purchasing 
the initial additional adsorber bed, when compared to the large 
increase in compliance assurance, is small.
---------------------------------------------------------------------------

    \52\ We are proposing to define the term ``breakthrough'' at 40 
CFR 63.2550(i) to mean the time when the level of HAP or total 
organic compound (TOC) detected is at the highest concentration 
allowed to be discharged from an adsorber system.
---------------------------------------------------------------------------

    Similar to regenerative adsorbers, in order to monitor performance 
deterioration, we are proposing measurements of HAP or TOC using a 
portable analyzer or chromatographic analysis for non-regenerative 
absorbers. We are proposing that these measurements 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 have 
included the option to reduce the frequency of monitoring with the 
portable analyzer from daily to weekly or monthly. If you choose this 
option, you would first be required to establish an average adsorber 
bed life. For periods when more than 2 months remain on the bed life, 
monthly monitoring can be conducted, and when more than 2 weeks remain 
on the bed life, weekly monitoring can be conducted.
b. Electronic Reporting
    The EPA is proposing that owners and operators of MON facilities 
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 Central 
Data Exchange (CDX) using the Compliance and Emissions Data Reporting 
Interface (CEDRI). A description of the electronic data submission 
process is provided in 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. The proposed 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 \53\ 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 monitoring systems 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. Flare

[[Page 69228]]

management plans would be uploaded as a PDF file. For compliance 
reports, the proposed rule requires that owners and operators use the 
appropriate spreadsheet template to submit information to CEDRI. A 
draft version of the proposed template for these reports is included in 
the docket for this rulemaking.\54\ The EPA specifically requests 
comment on the content, layout, and overall design of the template.
---------------------------------------------------------------------------

    \53\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
    \54\ See MON_Compliance_Report_Draft_Template.xlsx, which is 
available in the docket for this rulemaking.
---------------------------------------------------------------------------

    Additionally, the EPA has identified two broad circumstances in 
which electronic reporting extensions may be provided. In both 
circumstances, the decision to accept the claim of needing additional 
time to report is within the discretion of the Administrator, and 
reporting should occur as soon as possible. The EPA is providing these 
potential extensions to protect owners and operators from noncompliance 
in cases where they cannot successfully submit a report by the 
reporting deadline for reasons outside of their control. The situation 
where an extension may be warranted due to outages of the EPA's CDX or 
CEDRI which precludes an owner or operator from accessing the system 
and submitting required reports is addressed in 40 CFR 63.2520(h). The 
situation where an extension may be warranted due to a force majeure 
event, which 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 an owner or operator from complying with the requirement to 
submit a report electronically as required by this rule is addressed in 
40 CFR 63.2520(i). Examples of such events are acts of nature, acts of 
war or terrorism, or equipment failure or safety hazards beyond the 
control of the facility.
    The electronic submittal of the reports addressed in this proposed 
rulemaking will increase the usefulness of the data contained in those 
reports, is in keeping with current trends in data availability and 
transparency, will further assist in the protection of public health 
and the environment, will improve compliance by facilitating the 
ability of regulated facilities to demonstrate compliance with 
requirements and by facilitating the ability of delegated state, local, 
tribal, and territorial air agencies and the EPA to assess and 
determine compliance, and will ultimately reduce burden on regulated 
facilities, delegated air agencies, and the EPA. Electronic reporting 
also eliminates paper-based, manual processes, thereby saving time and 
resources, simplifying data entry, eliminating redundancies, minimizing 
data reporting errors, and providing data quickly and accurately to the 
affected facilities, air agencies, the EPA, and the public. Moreover, 
electronic reporting is consistent with the EPA's plan \55\ to 
implement Executive Order 13563 and is in keeping with the EPA's 
agency-wide policy \56\ developed in response to the White House's 
Digital Government Strategy.\57\ For more information on the benefits 
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.
---------------------------------------------------------------------------

    \55\ EPA's Final Plan for Periodic Retrospective Reviews, August 
2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \56\ E-Reporting Policy Statement for EPA Regulations, September 
2013. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
    \57\ Digital Government: Building a 21st Century Platform to 
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
---------------------------------------------------------------------------

3. Other Corrections
    There are several additional revisions that we are proposing to 40 
CFR part 63, subpart FFFF, to clarify text or correct typographical 
errors, grammatical errors, and cross-reference errors. These proposed 
editorial corrections and clarifications are summarized in Table 11 of 
this preamble.

          Table 11--Summary of Proposed Editorial and Minor Corrections to 40 CFR Part 63, Subpart FFFF
----------------------------------------------------------------------------------------------------------------
                                   Provision                                            Proposed revision
----------------------------------------------------------------------------------------------------------------
40 CFR 63.2435(c)(3)..........................................................  Remove the word ``future.''
40 CFR 63.2450(c)(2)..........................................................  Correct cross-reference error by
                                                                                 changing ``Sec.   63.2525(f)''
                                                                                 to ``Sec.   63.2525(e)(3) and
                                                                                 (4).''
40 CFR 63.2450(j)(1)(i).......................................................  Correct typo by changing ``an
                                                                                 Fourier'' to ``a Fourier''; and
                                                                                 clarify performance
                                                                                 specification requirements.
40 CFR 63.2450(k)(4)(iv)......................................................  Correct cross-reference error by
                                                                                 changing ``(b)(2)(ii)'' to
                                                                                 ``(c)(2)(ii).''
40 CFR 63.2450(l).............................................................  Correct typo by adding the
                                                                                 ``Sec.   '' symbol.
40 CFR 63.2460(b)(5)..........................................................  Change ``under either'' to ``if
                                                                                 you comply with one.''
40 CFR 63.2470(e)(3)..........................................................  Replace the phrase ``pounds per
                                                                                 square inch gage pressure
                                                                                 (psig)'' with ``psig'' because
                                                                                 the term is defined earlier in
                                                                                 the rule text.
40 CFR 63.2475(a).............................................................  Correct cross-reference error by
                                                                                 changing ``in paragraphs (b)
                                                                                 and (c) of this section'' to
                                                                                 ``in paragraph (b) of this
                                                                                 section.''
40 CFR 63.2520(c)(2)..........................................................  Correct cross-reference error by
                                                                                 changing ``Sec.
                                                                                 63.2460(c)(5)'' to ``Sec.
                                                                                 63.2450(k)(6).''
40 CFR 63.2520(e)(5)(iii)(A)..................................................  For clarification, change ``The
                                                                                 date and time'' to ``The start
                                                                                 date, start time, and duration
                                                                                 in hours.''
40 CFR 63.2520(e)(5)(iii)(B)..................................................  For clarification, change ``The
                                                                                 date, time, and duration that
                                                                                 each CEMS was out-of-control,
                                                                                 including the information in
                                                                                 63.8(c)(8).'' to ``The start
                                                                                 date, start time, and duration
                                                                                 in hours that each CEMS was out-
                                                                                 of-control and a description of
                                                                                 the corrective actions taken.''
40 CFR 63.2520(e)(5)(iii)(D)..................................................  For clarification, change ``A
                                                                                 summary of the total duration
                                                                                 of the deviation during the
                                                                                 reporting period'' to ``The
                                                                                 total duration in hours of all
                                                                                 deviations for each CMS during
                                                                                 the reporting period'' and add
                                                                                 ``the total operating time in
                                                                                 hours of the affected source
                                                                                 during the reporting period.''
40 CFR 63.2520(e)(5)(iii)(F)..................................................  For clarification, change ``A
                                                                                 summary of the total duration
                                                                                 of CMS downtime'' to ``The
                                                                                 total duration in hours of CMS
                                                                                 downtime for each CMS.''
40 CFR 63.2520(e)(5)(iii)(I)..................................................  For clarification, change ``A
                                                                                 brief description of the CMS''
                                                                                 to ``The monitoring equipment
                                                                                 manufacturer(s) and model
                                                                                 number(s) and the pollutant or
                                                                                 parameter monitored.''

[[Page 69229]]

 
40 CFR 63.2520(e)(8)..........................................................  For clarification, change
                                                                                 ``Records of process units
                                                                                 added to a PUG as specified in
                                                                                 Sec.   63.2525(i)(4) and
                                                                                 records of primary product
                                                                                 redeterminations as specified
                                                                                 in Sec.   63.2525(i)(5)'' to
                                                                                 ``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).''
40 CFR 63.2525(f).............................................................  Correct cross-reference error by
                                                                                 changing ``Sec.   63.2450(s)''
                                                                                 to ``Sec.   63.2450(p).''
40 CFR 63.2550(i).............................................................  Add definition for ``bench-scale
                                                                                 process.''
40 CFR 63.2550(i).............................................................  Change ``it is up to and
                                                                                 including the extruder, die
                                                                                 plate'' to remove ``extruder,''
                                                                                 in the definition of
                                                                                 ``miscellaneous organic
                                                                                 chemical manufacturing
                                                                                 process'' in bullet (6).
40 CFR 63.2550(i).............................................................  Define ``loading rack'' as 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. The term
                                                                                 ``loading rack'' is used in the
                                                                                 definition of ``transfer rack''
                                                                                 but ``loading rack'' is not
                                                                                 defined in the MON.
All Equations.................................................................  For clarification, renumber
                                                                                 equations in numerical order.
Table 12 to 40 CFR part 63, Subpart FFFF......................................  Add a row for ``Sec.
                                                                                 63.7(e)(4).''
----------------------------------------------------------------------------------------------------------------

F. What compliance dates are we proposing?

    Amendments to the MON proposed in this rulemaking for adoption 
under CAA section 112(d)(2) and (3) and CAA section 112(d)(6) are 
subject to the compliance deadlines outlined in the CAA under section 
112(i).
    For all of the requirements we are proposing under CAA sections 
112(d)(2), (3), and (d)(6), we are proposing all affected sources must 
comply with all of the amendments no later than 3 years after the 
effective date of the final rule, or upon startup, whichever is later. 
For existing sources, 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. (``Section 112(i)(3)'s three-
year maximum compliance period applies generally to any emission 
standard . . . promulgated under [section 112].'' Association of 
Battery Recyclers v. EPA, 716 F.3d 667, 672 (D.C. Cir. 2013)). 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. As provided in CAA section 112(i), all new 
affected sources would be required to comply with these requirements by 
the effective date of the final amendments to the MON standards or 
startup, whichever is later.
    We are proposing new operating and monitoring requirements for 
flares under CAA section 112(d)(2) and (3). We anticipate that these 
requirements would require the installation of new flare monitoring 
equipment and we project most MCPUs would install new control systems 
to monitor and adjust assist gas (air or steam) addition rates. Similar 
to the addition of new control equipment, these new monitoring 
requirements for flares would require engineering evaluations, 
solicitation and review of vendor quotes, contracting and installation 
of the equipment, and operator training. Installation of new monitoring 
and control equipment on flares will require the flare to be taken out 
of service. Depending on the configuration of the flares and flare 
header system, taking the flare out of service may also require a 
significant portion of the MCPU to be shutdown. Therefore, for all 
existing affected sources, and all new affected sources that commence 
construction or reconstruction after April 4, 2002, and on or before 
December 17, 2019, we are proposing that it is necessary to provide 3 
years after the effective date of the final rule (or upon startup, 
whichever is later) for owners or operators to comply with the new 
operating and monitoring requirements for flares. For all new affected 
sources that commenced construction or reconstruction after December 
17, 2019, we are proposing owners or operators comply with the new 
operating and monitoring requirements for flares by the effective date 
of the final rule (or upon startup, whichever is later).
    Under CAA section 112(d)(2) and (3), we are proposing new vent 
control requirements for bypasses. These requirements would typically 
require the addition of piping and potentially new control 
requirements. As these vent controls would most likely be routed to the 
flare, we are proposing, for all existing affected sources, and all new 
affected sources that commence construction or reconstruction after 
April 4, 2002, and on or before December 17, 2019, to provide 3 years 
after the effective date of the final rule for owners or operators to 
allow coordination of these bypass modifications with the installation 
of the new monitoring equipment for the flares. For all new affected 
sources that commenced construction or reconstruction after December 
17, 2019, we are proposing owners or operators comply with the new vent 
control requirements for bypasses by the effective date of the final 
rule (or upon startup, whichever is later).
    For atmospheric PRD in HAP service, we are establishing a work 
practice standard that requires a process hazard analysis and 
implementation of a minimum of three redundant measures to prevent 
atmospheric releases. Alternately, owners or operators may elect to 
install closed-vent systems to route these PRDs to a flare, drain (for 
liquid thermal relief valves), or other control system. We anticipate 
that sources will need 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. Therefore, for all existing affected sources, and all new 
affected sources that commence construction or reconstruction after 
April 4, 2002, and on or before December 17, 2019, we are proposing a 
compliance date of 3 years from the effective date of the final rule 
(or upon startup, whichever is later) for owners or operators to comply 
with the work practice standards for atmospheric PRD releases. For all 
new affected sources that commenced construction or reconstruction 
after December 17, 2019, we are proposing owners or operators comply 
with the work practice standards for atmospheric PRD releases

[[Page 69230]]

by the effective date of the final rule (or upon startup, whichever is 
later).
    Under our technology review for equipment leaks under CAA section 
112(d)(6), we are revising the leak definition for light liquid pumps 
at batch processes from 10,000 ppm to 1,000 ppm. Affected sources are 
currently monitoring light liquid pumps on a monthly basis, and the 
change we are proposing to lower the leak definition would require no 
additional equipment and would only result in identifying smaller leaks 
that require repair. Therefore, we believe that this change could be 
implemented quickly and are proposing a compliance date of 1 year after 
the effective date of the final rule, or upon startup, whichever is 
later, for all existing affected sources, and all new affected sources 
that commence construction or reconstruction after April 4, 2002, and 
on or before December 17, 2019 to comply with the proposed leak 
definition for light liquid pumps at batch processes. For all new 
affected sources that commenced construction or reconstruction after 
December 17, 2019, we are proposing owners or operators comply with the 
proposed leak definition for light liquid pumps at batch processes by 
the effective date of the final rule (or upon startup, whichever is 
later).
    As a result of our technology review for heat exchange systems, we 
are proposing to replace the existing leak definition and monitoring 
method with a new leak definition and monitoring method. We project 
some owners and operators would require engineering evaluations, 
solicitation and review of vendor quotes, contracting and installation 
of monitoring equipment, and operator training. In addition, facilities 
will need time to read and understand the amended rule requirements and 
update standard operating procedures. Therefore, we are proposing that 
all existing affected sources, and all new affected sources that 
commence construction or reconstruction after April 4, 2002, and on or 
before December 17, 2019 must comply with the new monitoring 
requirements for heat exchange systems no later than 3 years after the 
effective date of the final rule, or upon startup, whichever is later. 
For all new affected sources that commenced construction or 
reconstruction after December 17, 2019, we are proposing owners or 
operators comply with the new monitoring requirements for heat exchange 
systems by the effective date of the final rule (or upon startup, 
whichever is later).
    Additionally, as previously mentioned in this preamble, we are 
proposing under CAA section 112(f), new provisions for process vents 
and storage tanks at MON facilities emitting ethylene oxide, as well as 
proposing to implement one of two co-proposed control options for 
equipment leaks. The proposed provisions may require additional 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 
pounds per year (for all combined process vents), then a new control 
system will need to be installed. Therefore, we are proposing a 
compliance date of 2 years after the effective date of the final rule, 
or upon startup, whichever is later for all existing affected sources, 
and all new affected sources that commence construction or 
reconstruction after April 4, 2002, and on or before December 17, 2019 
to comply with the proposed ethylene oxide requirements. For all new 
affected sources that commenced construction or reconstruction after 
December 17, 2019, we are proposing owners or operators comply with the 
ethylene oxide requirements by the effective date of the final rule (or 
upon startup, whichever is later).
    Finally, we are proposing to change the requirements for SSM by 
removing the exemption from the requirements to meet the standard 
during SSM periods and by removing the requirement to develop and 
implement an SSM plan. We are also proposing electronic reporting 
requirements. We are positing that facilities would need some time to 
successfully accomplish these revisions, including time to read and 
understand the amended rule requirements, to evaluate their operations 
to ensure that they can meet the standards during periods of startup 
and shutdown, as defined in the rule, and make any necessary 
adjustments, including making adjustments to standard operating 
procedures, and to convert reporting mechanisms to install necessary 
hardware and software. The EPA recognizes the confusion that multiple 
different compliance dates for individual requirements would create and 
the additional burden such an assortment of dates would impose. From 
our assessment of the timeframe needed for compliance with the entirety 
of the proposed revisions to SSM requirements as well as the new 
proposed electronic reporting requirements for flare management plans, 
compliance reports, and performance evaluation reports, the EPA 
considers a period of 3 years after the effective date of the final 
rule to be the most expeditious compliance period practicable and, 
thus, is proposing that all affected sources be in compliance with 
these revised requirements upon initial startup or within 3 years of 
the effective date of the final rule, whichever is later. However, we 
are proposing to provide 60 days after the effective date of the final 
rule (or upon startup, whichever is later) for owners or operators to 
comply with the requirement to report performance test results and 
reports electronically.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    There are 201 MON facilities currently operating. A complete list 
of facilities that are currently subject to the MON is available in 
Appendix 1 of the document titled 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.

B. What are the air quality impacts?

    At the current level of control, estimated ethylene oxide emissions 
from the modeling file were approximately 9.5 tpy from the eight 
facilities with emission process groups in ethylene oxide service. For 
co-proposed Control Option 1, we estimated ethylene oxide emissions 
reductions of 8.8 tpy for equipment leaks, storage tanks, and process 
vents in ethylene oxide service. For co-proposed Control Option 2, we 
estimated ethylene oxide emissions reductions of 9.0 tpy for equipment 
leaks, storage tanks, and process vents in ethylene oxide service.
    At the current level of control, we estimate HAP emissions for 194 
MON facilities of approximately 2,558 tpy and VOC emissions of 
approximately 19,719 tpy, based on the MON emissions inventory. We 
estimate that HAP emissions reductions would range from 52 tpy (based 
on model plant estimates) to 116 tpy (based on the MON emissions 
inventory) and VOC emissions reductions range from 283 tpy (based on 
the MON emissions inventory) to 385 tpy (based on model plant 
estimates) as a result of the proposed amendments for MON equipment 
leaks and heat exchange systems. Note, these emissions reductions do 
not consider the potential excess emissions reductions from flares that 
could result from the proposed requirements; we estimated flare excess

[[Page 69231]]

emissions reductions of 263 tpy HAP (based on model plant estimates) 
and 1,254 tpy VOC (based on model plant estimates). If we considered 
the flare excess emissions, the total emissions reductions as a result 
of the proposed amendments were estimated between 315 and 379 tpy of 
HAP and between 1,537 and 1,639 tpy of VOC. These emissions reductions 
are documented in the following memoranda, which is 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, Clean Air Act Section 112(d)(6) 
Technology Review for Heat Exchange Systems Located in the 
Miscellaneous Organic Chemical Manufacturing Source Category, Analysis 
of Control Options for Storage Tanks and Process Vents Emitting 
Ethylene Oxide Located in the Miscellaneous Organic Chemical 
Manufacturing Source Category, Analysis of Control Options for 
Equipment Leaks at Processes that use Ethylene Oxide Located in the 
Miscellaneous Organic Chemical Manufacturing Source Category, 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 2019 Risk and Technology Review Proposed Rule.

C. What are the cost impacts?

    The nationwide costs of the proposed amendments are presented in 
Table 12 of this preamble for (1) all MON sources, (2) only MON sources 
not expected to be affected by the proposed ethylene oxide-specific 
controls (i.e., equipment leaks, heat exchange systems, flares, PRDs, 
maintenance vents, recordkeeping and reporting), and (3) only MON 
sources expected to be affected by the proposed ethylene oxide controls 
(i.e., storage tanks, process vents, equipment leaks). As described in 
this preamble, for ethylene oxide sources, we are co-proposing two 
options which differ only by the proposed equipment leak standards. The 
first option (i.e., Control Option 1) proposes 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. The second 
option (i.e., Control Option 2) proposes that different equipment leak 
standards will apply to facilities in ethylene oxide service, depending 
on whether their cancer risk is lower than 100-in-1 million (i.e., 
lower the leak definition for batch pumps to 1,000 ppm and require 
connector monitoring at a leak definition of 500 ppm) or greater than 
100-in-1 million (i.e., require leakless pumps, leakless valves, and 
connector monitoring at a leak definition of 100 ppm). These costs are 
presented in different columns in Table 12 of this preamble, and are 
referred to as ``Option 1'' and ``Option 2,'' respectively.

                                                      Table 12--Total Capital and Annualized Costs
                                                                         [2016$]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Option 1                                        Option 2
                                                         -----------------------------------------------------------------------------------------------
                                                                               Total           Total                           Total           Total
                                                                            annualized      annualized                      annualized      annualized
                                                           Total capital    costs  w/o       costs  w/     Total capital    costs  w/o       costs  w/
                                                               costs         recovery        recovery          costs         recovery        recovery
                                                                              credits         credits                         credits         credits
--------------------------------------------------------------------------------------------------------------------------------------------------------
All MON Sources--Total..................................      42,400,000      12,600,000      12,300,000      43,000,000      12,700,000      12,400,000
MON Sources w/o Ethylene Oxide Controls--Total..........      39,700,000      10,900,000      10,500,000      39,700,000      10,900,000      10,500,000
    Flares \1\..........................................      17,200,000       4,090,000       4,090,000      17,200,000       4,090,000       4,090,000
    Equipment Leaks \2\.................................         829,000         150,000          82,000         829,000         150,000          82,000
    Pressure Relief Devices \3\.........................      18,700,000       4,770,000       4,770,000      18,700,000       4,770,000       4,770,000
    Maintenance Vents \3\...............................  ..............           2,340           2,340  ..............           2,340           2,340
Heat Exchange Systems \4\...............................       1,480,000         261,000        (14,300)       1,480,000         261,000        (14,300)
Recordkeeping and Reporting.............................       1,490,000       1,610,000       1,610,000       1,490,000       1,610,000       1,610,000
MON Sources w/Ethylene Oxide Controls--Total............       2,720,000       1,760,000       1,750,000       3,320,000       1,860,000       1,850,000
    Equipment Leaks \5\.................................          76,200          48,500          45,300         674,000         149,000         145,000
    Process Vents \6\...................................       2,180,000         914,000         914,000       2,180,000         914,000         914,000
    Storage Tanks \6\...................................         466,000         796,000         796,000         466,000         796,000         796,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 titled Control Option Impacts for Flares Located in the Miscellaneous Organic
  Chemical Manufacturing Source Category, in the docket for this rulemaking.
\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 memorandum
  titled Clean Air Act Section 112(d)(6) Technology Review for Equipment Leaks Located in the Miscellaneous Organic Chemical Manufacturing Source
  Category, in the docket for this rulemaking.
\3\ Pressure relief device costs were developed to comply with the proposed work practice standard and include implementation of three prevention
  measures, performing root cause analysis and corrective action, and purchasing pressure relief device 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 titled Review of Regulatory Alternatives for Certain Vent Streams in the Miscellaneous Organic Chemical Manufacturing Source Category, in
  the docket for this rulemaking.
\4\ Heat exchange systems costs include the use of the Modified El Paso Method to monitor for leaks, and are discussed in the memorandum titled Clean
  Air Act Section 112(d)(6) Technology Review for Heat Exchange Systems in the Miscellaneous Organic Chemical Manufacturing Source Category, in the
  docket for this rulemaking.

[[Page 69232]]

 
\5\ Equipment leak costs for equipment in ethylene oxide service include two co-proposed options, Control Options 1 and 2. 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. Control Option 2 includes the same controls as Control Option 1 for streams in ethylene oxide service,
  except that more stringent controls are applied to the two facilities with risks above 100-in-1 million. These more stringent controls include
  requiring light liquid pumps in ethylene oxide service to be leakless with annual monitoring, gas/vapor and light liquid valves in ethylene oxide
  service to either be leakless with annual monitoring or not be leakless and be monitored quarterly with equipment considered to be leaking if an
  instrument reading above background is found, and connector monitoring for connectors in ethylene oxide service at a leak definition of 100 ppmv with
  monthly monitoring. Costs are discussed in the memorandum titled Analysis of Control Options for Equipment Leaks at Processes that use Ethylene Oxide
  Located in the Miscellaneous Organic Chemical Manufacturing Source Category, in the docket for this rulemaking.
\6\ 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 memorandum titled Analysis of Control Options for Storage Tanks and Process Vents Emitting Ethylene Oxide
  Located in the Miscellaneous Organic Chemical Manufacturing Source Category, in the docket for this rulemaking.

D. What are the economic impacts?

    The EPA conducted economic impact analyses for this proposal, as 
detailed in the memorandum, Economic Impact and Small Business 
Screening Assessments for the Proposed Amendments to the National 
Emission Standards for Hazardous Air Pollutants: Miscellaneous Organic 
Chemical Manufacturing, which is available in the docket for this 
action. For the proposed amendments, 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 ratio, 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 facilities affected by the proposed amendments. Of 
these, 17 facilities, or 8.5 percent, are small entities. We calculated 
the cost-to-sales ratios for all the affected facilities to determine 
(1) the magnitude of the costs of the proposed amendments and (2) 
whether there would be a significant impact on small entities. To be 
conservative, we used facility-specific costs without recovery credits. 
For the two options for all firms the average cost-to-sales ratio is 
approximately 0.02 percent; the median cost-to-sales ratio is less than 
0.01 percent; and the maximum cost-to-sales ratio is approximately 0.89 
percent. For large firms, the average cost-to-sales ratio is less than 
0.01 percent; the median cost-to-sales ratio is less than 0.01 percent; 
and the maximum cost-to-sales ratio is approximately 0.47 percent. For 
small firms, the average cost-to-sales ratio is approximately 0.23 
percent, the median cost-to-sales ratio is 0.10 percent, and the 
maximum cost-to-sales ratio is 0.89 percent. The costs of the proposal 
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.

E. What are the benefits?

    EPA did not monetize the benefits from the estimated emission 
reductions of HAP associated with this proposed action. However, we 
expect this proposed action would provide benefits associated with HAP 
emission reductions and lower risk of adverse health effects in 
communities near facilities subject to the MON.

VI. Request for Comments

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

VII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category 
risk and demographic analyses and instructions are available for 
download on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/miscellaneous-organic-chemical-manufacturing-national-emission. The data files include detailed information for each HAP 
emissions release point for the facilities in the source category.
    If you believe that the data are not representative or are 
inaccurate, please identify the data in question, provide your reason 
for concern, and provide any ``improved'' data that you have, if 
available. When you submit data, we request that you provide 
documentation of the basis for the revised values to support your 
suggested changes. To submit comments on the data downloaded from the 
RTR website, complete the following steps:
    1. Within this downloaded file, enter suggested revisions to the 
data fields appropriate for that information.
    2. Fill in the commenter information fields for each suggested 
revision (i.e., commenter name, commenter organization, commenter email 
address, commenter phone number, and revision comments).
    3. Gather documentation for any suggested emissions revisions 
(e.g., performance test reports, material balance calculations).
    4. Send the entire downloaded file with suggested revisions in 
Microsoft[supreg] Access format and all accompanying documentation to 
Docket ID No. EPA-HQ-OAR-2018-0746 (through the method described in the 
ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or multiple 
facilities, you need only submit one file for all facilities. The file 
should contain all suggested changes for all sources at that facility 
(or facilities). We request that all data revision comments be 
submitted in the form of updated Microsoft[supreg] Excel files that are 
generated by the Microsoft[supreg] Access file. These files are 
provided on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/miscellaneous-organic-chemical-manufacturing-national-emission.

VIII. 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 Order 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 OMB for review because it raises novel legal or

[[Page 69233]]

policy issues. Any changes made in response to OMB recommendations have 
been documented in the docket. The EPA prepared an analysis of the 
potential economic impacts associated with this action. This analysis, 
Economic Impact and Small Business Screening Assessments for Proposed 
Amendments to the National Emission Standards for Hazardous Air 
Pollutants: Miscellaneous Organic Chemical Manufacturing, is available 
in the docket for this rulemaking.

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

    This action is expected to be an Executive Order 13771 regulatory 
action. Details on the estimated costs of this proposed rule can be 
found in the EPA's analysis of the potential costs and benefits 
associated with this action.

C. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed 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 1969.08. You can find a copy of the ICR in the 
docket for this rulemaking, and it is briefly summarized here.
    We are proposing 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). The proposed amendments also require electronic 
reporting, remove the malfunction exemption, and impose other revisions 
that affect reporting and recordkeeping. This information would be 
collected to assure compliance with 40 CFR part 63, 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 facilities.
    Frequency of response: Semiannual or annual. Responses include 
notification of compliance status reports and semiannual compliance 
reports.
    Total estimated burden: 12,118 hours (per year) for the responding 
facilities and 2,413 hours (per year) for the Agency. Burden is defined 
at 5 CFR 1320.3(b).
    Total estimated cost: $3,639,019 (per year), which includes 
$2,412,332 annualized capital and operation and maintenance costs for 
the responding facilities.
    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.
    Submit your comments on the Agency's need for this information, the 
accuracy of the provided burden estimates, and any suggested methods 
for minimizing respondent burden to the EPA using the docket identified 
at the beginning of this rule. You may also send your ICR-related 
comments to OMB's Office of Information and Regulatory Affairs via 
email to OIRA_submission@omb.eop.gov, Attention: Desk Officer for the 
EPA. Since OMB is required to make a decision concerning the ICR 
between 30 and 60 days after receipt, OMB must receive comments no 
later than January 16, 2020. The EPA will respond to any ICR-related 
comments in the final rule.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will impose requirements on the small entities in the NESHAP and 
associated regulated industrial source category described in section 
I.A of this preamble. This action is projected to affect 201 
facilities, and 17 of these facilities are small entities. For the 
small entities, the average cost-to-sales ratio is approximately 0.23 
percent. Additional details of the associated analysis are presented in 
the memorandum, Economic Impact and Small Business Screening 
Assessments Analysis for the Proposed Amendments to the National 
Emissions Standards for Hazardous Air Pollutants: Miscellaneous Organic 
Chemical Manufacturing, which is available in the docket for this 
action.

E. Unfunded Mandates Reform Act (UMRA)

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

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 action are owned or operated by 
tribal governments or located within tribal lands. Thus, Executive 
Order 13175 does not apply to this action.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children. This action's health and risk assessments are contained in 
sections III.A and C and sections IV.B and C 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 2019 Risk and Technology Review Proposed 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 economic impact of this 
proposed rule should be minimal for MON facilities and their parent 
companies (which are engaged in the energy sector).

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

    This action involves technical standards. Therefore, the EPA 
conducted searches for the Miscellaneous Organic Chemical Manufacturing 
NESHAP through the Enhanced National Standards Systems Network (NSSN) 
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, 29 of 40 CFR part 60, appendix A, 301, 305, 316, 
320 of 40 CFR part 63, 624, 625 of 40

[[Page 69234]]

CFR part 136, appendix A, 1624, 1625, 1666, 1671 of CFR part 136, 
appendix A, 5030B (SW-846), 5031, 8260, 8260B (SW-846), 8260D (SW-846), 
8270, 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 considered it as a potential 
equivalent method. We reviewed all potential standards to determine the 
practicality of the VCS for this rule. This review requires significant 
method validation data that meet the requirements of EPA Method 301 of 
appendix A to 40 CFR part 63 for accepting alternative methods or 
scientific, engineering, and policy equivalence to procedures in the 
EPA reference methods. The EPA may reconsider determinations of 
impracticality when additional information is available for particular 
VCS.
    No applicable VCS were identified for EPA Methods 1A, 2A, 2D, 2F, 
2G, 21, 22, 25D, 305, 316, 625, 1624, 1625, 1666, 1671, 5030B, 8260, 
8260B, 8260D, 8270C, and 8430 (SW-846). The following five VCS were 
identified as acceptable alternatives to the EPA test methods for the 
purpose of this rule.
    The EPA proposes to use the VCS ANSI/ASME PTC 19.10-1981 Part 10 
(2010), ``Flue and Exhaust Gas Analyses,'' \58\ as an acceptable 
alternative to EPA Method 3B for the manual procedures only and not the 
instrumental procedures. The ANSI/ASME PTC 19.10-1981-Part 10 method 
incorporates both manual and instrumental methodologies for the 
determination of oxygen content. The manual method segment of the 
oxygen determination is performed through the absorption of oxygen. The 
EPA is not proposing to incorporate this VCS by reference. This method 
is available both in the docket for this rulemaking and at the American 
National Standards Institute (ANSI), 1899 L Street NW, 11th floor, 
Washington, DC 20036 and the American Society of Mechanical Engineers 
(ASME), Three Park Avenue, New York, NY 10016-5990. See https://wwww.ansi.org and https://www.asme.org.
---------------------------------------------------------------------------

    \58\ We identified this same 40 CFR part 63, subpart SS VCS that 
was also identified in the NTTAA review for the Ethylene Production 
RTR and is already being proposed as an amendment in that action 
(for further information, see EPA Docket ID No. EPA-HQ-OAR-2017-0357 
and 84 FR 54330).
---------------------------------------------------------------------------

    Additionally, the EPA proposes to use the 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 of appendix A-6 to 40 CFR part 
60 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 as measurable. We are proposing that ASTM D6420-18 should not be 
used for methane and ethane because the atomic mass is less than 35; 
and ASTM D6420 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 VOCs. The test method provides on-site 
analysis of extracted, unconditioned, and unsaturated (at the 
instrument) gas samples from stationary sources.
    Also, the EPA proposes to use the VCS ASTM D6784-02 (2008) 
reapproved, ``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
    In addition, the EPA proposes to use the VCS ASTM D6348-12e1, 
``Determination of Gaseous Compounds by Extractive Direct Interface 
Fourier Transform (FTIR) Spectroscopy,'' \58\ as an acceptable 
alternative to EPA Method 320 of appendix A to 40 CFR part 63 with 
caveats requiring inclusion of selected annexes to the standard as 
mandatory. The ASTM D6348-12e1 method is an extractive FTIR 
Spectroscopy-based field test method and is used to quantify gas phase 
concentrations of multiple target compounds in emission streams from 
stationary sources. The EPA is not proposing to incorporate this VCS by 
reference. We are proposing the test plan preparation and 
implementation in the Annexes to ASTM D 6348-03, Sections Al through A8 
are mandatory; and in ASTM D6348-03 Annex A5 (Analyte Spiking 
Technique), the percent (%) R must be determined for each target 
analyte (Equation A5.5). We are proposing that in order for the test 
data to be acceptable for a compound, %R must be 70% >= R <= 130%. If 
the %R value does not meet this criterion for a target compound, the 
test data is not acceptable for that compound and the test must be 
repeated for that analyte (i.e., the sampling and/or analytical 
procedure should be adjusted before a retest). We are proposing that 
the %R value for each compound be reported in the test report, and all 
field measurements be corrected with the calculated %R value for that 
compound by using the following equation:

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

    Furthermore, the EPA proposes to use the VCS ASTM D5790-95 (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). We are proposing that, 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 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 (2012) (see 84 FR 47375), the EPA is 
not proposing to incorporate this specific aspect of this VCS by 
reference.
    The four ASTM methods (ASTM D6420-18, ASTM D6784-02 (2008) 
reapproved, ASTM D6348-12e1, and ASTM D5790-95 (2012)) are available 
both in the docket for this rulemaking and at ASTM International, 1850 
M Street NW, Suite 1030, Washington, DC 20036. See https://www.astm.org/.

[[Page 69235]]

    Finally, the search identified 23 other VCS that were potentially 
applicable for this rule in lieu of the EPA reference methods. After 
reviewing the available standards, the EPA determined that 23 candidate 
VCS identified for measuring emissions of pollutants or their 
surrogates subject to emission standards in the rule would not be 
practical due to lack of equivalency, documentation, validation data, 
and other important technical and policy considerations. Additional 
information for the VCS search and determinations can be found in the 
memorandum, Voluntary Consensus Standard Results for National Emission 
Standards for Hazardous Air Pollutants: Miscellaneous Organic Chemical 
Manufacturing NESHAP RTR, which is available in the docket for this 
action.
    The EPA welcomes comments on this aspect of the proposed rulemaking 
and, specifically, invites the public to identify potentially 
applicable VCS, and to explain why the EPA should use such standards in 
this regulation.

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 (58 FR 7629, February 16, 1994). 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 proposed controls, and emissions reductions from 
the proposed revisions will benefit these groups the most.
    The documentation for this decision is contained in sections IV.B 
and C 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, which is available in the docket for this action.

List of Subjects in 40 CFR Part 63

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

    Dated: November 1, 2019.
Andrew R. Wheeler,
Administrator.

    For the reasons set forth in the preamble, the Environmental 
Protection Agency proposes to amend 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--[Amended]

0
2. Section 63.14 is amended by:
0
a. Revising paragraph (h)(72);
0
 b. Redesignating paragraphs (h)(92) through (111) as paragraphs 
(h)(93) through (1112);
0
c. Adding new paragraph (h)(92); and
0
d. Revising newly redesignated paragraph (h)(98).
    The revisions and addition read as follows:

Sec.  63.14  Incorporations by reference.

* * * * *
    (h) * * *
    (72) ASTM D5790-95 (2012), Standard Test Method for Measurement of 
Purgeable Organic Compounds in Water by Capillary Column Gas 
Chromatography/Mass Spectrometry, IBR approved for Sec.  63.2485(h) and 
Table 4 to subpart UUUU.
* * * * *
    (92) ASTM D6420-18, Standard Test Method for Determination of 
Gaseous Organic Compounds by Direct Interface Gas Chromatography-Mass 
Spectrometry, IBR approved for Sec.  63.2450(j).
* * * * *
    (98) 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), 63.11647(a) and (d), 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.
* * * * *

Subpart FFFF--[Amended]

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 63. 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 paragraph (a) introductory 
text and paragraph (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 (6) of this 
section upon initial startup or [date 3 years after date of publication 
of final rule in the Federal Register], whichever is later. All 
affected sources that commenced construction or reconstruction after

[[Page 69236]]

December 17, 2019, must be in compliance with the requirements listed 
in paragraphs (g)(1) through (6) of this section upon initial startup, 
or [date of publication of final rule in the Federal Register], 
whichever is later.
    (1) The general requirements specified in Sec.  63.2450(a)(2), 
(e)(4) through (7), (g)(6) and (7), (i)(3), (j)(5)(ii) and (6), 
(k)(1)(ii), (7), and (8), (t), and (u), Sec.  63.2520(d)(3), (e)(11) 
through (13), Sec.  63.2525(m) and (n), and Sec.  63.2535(m).
    (2) For process vents, the requirements specified in Sec.  
63.2455(d), Sec.  63.2520(e)(14), and Sec.  63.2525(p).
    (3) For equipment leaks and pressure relief devices, the 
requirements specified in Sec.  63.2480(e) and (f), Sec.  63.2520(d)(4) 
and (e)(14), and Sec.  63.2525(q).
    (4) 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), and (p) and (q).
    (5) For heat exchange systems, the requirements specified in Sec.  
63.2490(d), Sec.  63.2520(e)(16), and Sec.  63.2525(r).
    (6) The other notification, reports, and records requirements 
specified in Sec.  63.2500(g), Sec.  63.2520(e)(5)(ii)(D), Sec.  
63.2520(e)(5)(iii)(M) and (N), and Sec.  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 light liquid pumps in Sec.  63.2480(b)(6) and 
(c)(10) upon initial startup or [date 1 year after date of publication 
of final rule in the Federal Register], whichever is later. All 
affected sources that commenced construction or reconstruction after 
December 17, 2019, must be in compliance with the requirements for 
light liquid pumps in Sec.  63.2480(b)(6) and (c)(10), except for 
equipment in ethylene oxide service, upon initial startup, or [date of 
publication of final rule in the Federal Register], 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.  63.2470(b) and (c)(4), 
Sec.  63.2492, Sec.  63.2493, Sec.  63.2520(d)(5) and (e)(17), Sec.  
63.2525(s), 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 [date 2 years after date of publication 
of final rule in the Federal Register], 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.  63.2470(b) and (c)(4), Sec.  63.2492, 
Sec.  63.2493, Sec.  63.2520(d)(5) and (e)(17), Sec.  63.2525(s), 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 [date of publication of final rule in the Federal 
Register], whichever is later.
0
5. Section 63.2450 is amended by:
0
a. Revising paragraph (a), paragraph (c)(2) introductory text, and 
paragraphs (e)(1) through (3);
0
b. Adding paragraphs (e)(4) through (7);
0
c. Revising paragraph (f) introductory text, paragraph (g) introductory 
text, paragraphs (g)(3)(ii), and (g)(5);
0
d. Adding paragraphs (g)(6) and (7);
0
e. Revising paragraphs (i) introductory text and (i)(2);
0
f. Adding paragraph (i)(3);
0
g. Revising paragraph (j) introductory text, paragraph (j)(1) 
introductory text, paragraphs (j)(1)(i), (j)(2)(iii), and (j)(3) 
through (j)(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 (k)(8);
0
k. Revising paragraphs (l), (o), and (p); and
0
l. Adding paragraphs (t) and (u).
    The revisions and additions read as follows:

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

    (a) 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 (u) 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

[[Page 69237]]

section, and the requirements of Sec.  63.994 and the requirements 
referenced therein. If you use a halogen reduction device before a 
combustion 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 [date 60 days after date of publication 
of final rule in the Federal Register], 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 40 CFR part 63, subpart SS.
    (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) 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) Sec.  63.996(c)(2)(ii) of subpart SS.
    (vii) Sec.  63.997(e)(1)(i) of subpart SS.
    (viii) The term ``breakdowns'' in Sec. Sec.  63.998(b)(2)(i) of 
subpart SS.
    (ix) Sec.  63.998(b)(2)(iii) of subpart SS.
    (x) The phrase ``other than start-ups, shutdowns or malfunctions'' 
in Sec.  63.998(b)(5)(i)(A) 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 ``except as provided in paragraphs (b)(6)(i)(A) 
and (B) of this section'' in Sec.  63.998(b)(6)(i) of subpart SS.
    (xiii) The second sentence of Sec.  63.998(b)(6)(ii) of subpart SS.
    (xiv) Sec.  63.998(c)(1)(ii)(D), (E), (F), and (G) of subpart SS.
    (xv) Sec.  63.998(d)(1)(ii) of subpart SS.
    (xvi) Sec.  63.998(d)(3)(i) and (ii) 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 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 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 (xi) of this section. This requirement 
also applies to any flare using fuel gas from a fuel gas system, of 
which 50 percent or more of the fuel gas is derived from an MCPU that 
has processes and/or equipment in ethylene oxide service or that 
produces olefins or polyolefins. For purposes of compliance with this 
paragraph, the following terms are defined in Sec.  63.641 of subpart 
CC: Assist air, assist steam, center steam, combustion zone, combustion 
zone gas, flare, flare purge gas, flare supplemental gas, flare sweep 
gas, flare vent gas, lower steam, net heating value, perimeter assist 
air, pilot gas, premix assist air, total steam, and upper steam.
    (i) 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.
    (ii) When determining compliance with the flare tip velocity and 
combustion zone operating limits specified in Sec.  63.670(d) and (e), 
the initial 15-minute block period starts with the 15-minute block that 
includes a full 15 minutes of the flaring event.
    (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/). If you claim some of the information in your flare 
management plan is confidential business information (CBI), submit a 
version with the CBI omitted via CEDRI. A complete plan, including 
information claimed to 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.
    (v) Substitute ``MCPU'' for each occurrence of ``petroleum 
refinery.''
    (vi) Each occurrence of ``refinery'' does not apply.
    (vii) 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 a continuously lit pilot flame 
capable of igniting all regulated material

[[Page 69238]]

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) You must ensure that if a stage of burners on the pressure-
assisted multi-point flare uses cross-lighting, that the distance 
between any two burners in series on that stage is no more than 6 feet; 
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 of subpart CC 
of this part.
    (viii) 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)(viii)(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 of 
40 CFR part 63, subpart CC, for the process mass spectrometer. You may 
use the alternative sampling line temperature allowed under Net Heating 
Value by Gas Chromatograph in Table 13 of 40 CFR part 63, subpart CC.
    (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 of this subpart.
[GRAPHIC] [TIFF OMITTED] TP17DE19.000

Where:

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

    (ix) 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 of this subpart.
[GRAPHIC] [TIFF OMITTED] TP17DE19.001

Where:

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

    (x) 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 Sec.  63.2520(e)(11).
    (xi) 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).
    (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 a vent stream to the atmosphere or to a control device 
not meeting the requirements specified in Table 1 through Table 7 of 
this subpart is an emissions standards deviation. Equipment such as low 
leg drains and equipment subject to Sec.  63.2480 are not subject to 
this paragraph (e)(6). Open-ended valves or lines that use a cap, blind 
flange, plug, or second valve and follow the requirements specified in 
Sec.  60.482-6(a)(2), (b), and (c) are also not subject to this 
paragraph (e)(6). You must also comply with the requirements specified 
in paragraphs (e)(6)(i) through (iv) 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.  63.148(j)(2) and (3) of subpart G, and 
Sec.  63.148(h)(3) of subpart G, in addition to the applicable 
requirements specified in Sec.  63.2485(q) of this section, 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) of

[[Page 69239]]

subpart G, and Sec.  63.118(f)(3) and (4) of subpart G, in addition to 
the applicable requirements specified in Sec.  63.2480(f) and Sec.  
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.  63.998(d)(1)(ii) and 
Sec.  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 subpart G, then you must continue to comply with 
the requirements in Sec.  65.143(a)(3) of subpart G and the 
recordkeeping and reporting requirements in Sec.  65.163(a)(1) of 
subpart G and Sec.  65.166(b) of subpart G; 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).
    (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) and the 
requirements in Sec.  63.983, and you must install a system of dual 
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.
    (ii) Monitor the HAP or total organic compound (TOC) concentration 
daily through a sample port at the outlet of the first adsorber bed in 
series. 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 or Method 25A at 40 CFR part 60, appendix A-7 using 
propane as the calibration gas.
    (iii) Comply with paragraph (e)(7)(iii)(A) of this section, and you 
may reduce your 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, 
``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.
    (B) In lieu of the daily monitoring, you may reduce your monitoring 
frequency by establishing the average adsorber bed life. To establish 
the average adsorber bed life, you must conduct daily monitoring of the 
HAP or TOC concentration of the first adsorber bed in series until 
breakthrough, as defined in Sec.  63.2550(i), occurs for the first 
three adsorber bed change-outs. You must reestablish an average 
adsorber bed life if you change the adsorbent brand or type, or if any 
process changes are made that would lead to a lower bed lifetime. Once 
the average life of the bed is determined, you may conduct ongoing 
monitoring, as specified in paragraphs (e)(7)(iii)(B)(1) and (2) of 
this section.
    (1) You may conduct monthly monitoring if the adsorbent has more 
than 2 months of life remaining, based on the average adsorber bed 
life, as established in paragraph (e)(7)(iii)(B) of this section, and 
the date the adsorbent was last replaced.
    (2) You may conduct weekly monitoring if the adsorbent has more 
than 2 weeks of life remaining, based on the average adsorber bed life, 
established in paragraph (e)(7)(iii)(B) of this section, and the date 
the adsorbent was last replaced.
    (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 section apply instead of or in 
addition to the requirements specified in subpart SS of this part 63.
* * * * *
    (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 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 and the other 
HAP emissions measured using Method 18 or 25A.
* * * * *
    (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) 
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.
* * * * *
    (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

[[Page 69240]]

using Equation 3 in Sec.  63.2460; 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) 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 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, you must also comply with appendix 
F, procedure 1 of 40 CFR part 60. 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 [date of publication of final rule in the Federal Register], 
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 to measure hydrogen halide, other than hydrogen 
chloride, and halogen HAP or CEMS meeting the requirements of 
Performance Specification 18 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.
* * * * *
    (2) * * *
    (iii) For CEMS meeting Performance Specification 8 used to monitor 
performance of a noncombustion device, determine the predominant 
organic HAP using either process knowledge or the screening procedures 
of Method 18 on the control device inlet stream, calibrate the monitor 
on the predominant organic HAP, and report the results as C1. Use 
Method 18 of appendix A-6 of 40 CFR part 60, Method 320 of appendix A 
to 40 CFR part 63, 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 inSec.  63.8 and according to the 
applicable Performance Specification of 40 CFR part 60, appendix B, 
except that the schedule in Sec.  63.8(e)(4) does not apply, and before 
[date 60 days after date of publication of final rule in the Federal 
Register], the results of the performance evaluation must be included 
in the notification of compliance status report. Beginning on and after 
[date 60 days after date of publication of final rule in the Federal 
Register], 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).
    (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) 
you must keep the written procedures required by Sec.  63.8(d)(2) 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). In addition to the information required in Sec.  
63.8(d)(2), 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), (c)(3), (c)(4)(ii), 
(c)(7), and (c)(8);
    (vi) Ongoing recordkeeping and reporting procedures in accordance 
with the general requirements of Sec.  63.10(c) and (e)(1).
    (k) Continuous parameter monitoring. The provisions in paragraphs 
(k)(1) through (68) of this section apply in addition to the 
requirements for continuous parameter monitoring system (CPMS) in 
subpart SS of this part 63.
    (1) You must comply with paragraphs (k)(1)(i) and (ii) of this 
section.

[[Page 69241]]

    (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 Sec.  63.2450(e)(4), 
as applicable.
* * * * *
    (l) Startup, shutdown, and malfunction. Sections Sec.  
63.152(f)(7)(ii) through (iv) and Sec.  63.998(b)(2)(iii) and 
(b)(6)(i)(A), which apply to the exclusion of monitoring data collected 
during periods of SSM from daily averages, do not apply for the 
purposes of this subpart.
* * * * *
    (o) You may not use a flare to control halogenated vent streams or 
hydrogen halide and halogen HAP emissions.
    (p) 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.
* * * * *
    (t) 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 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.
0
6. Section 63.2455 is amended by revising paragraph (a) and adding 
paragraph (d) 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 (d) of this 
section, Sec.  63.2492, and Sec.  63.2493(a) through (c).
* * * * *
    (d) 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 (d)(1) through 
(3) of this section for each maintenance vent.
    (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 Sec.  63.2450(e)(2) or (5), 
as applicable, or a non-flare control device meeting the requirements 
in Sec.  63.2450(e)(4) 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.
    (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 (d)(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 (d)(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 (d)(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
7. Section 63.2460 is amended by:
0
a. Revising paragraph (a), paragraph (b)(5) introductory text, 
paragraph (b)(5)(iii), paragraph (b)(6) introductory text, paragraphs 
(c)(2)(i) and (ii), (c)(2)(v), and paragraph (c)(6) introductory text;
0
b. Redesignating Equation 1 to paragraph (c)(6) as Equation 3;
0
c. Revising paragraphs (c)(9) introductory text, (c)(9)(ii) 
introductory text, paragraphs (c)(9)(ii)(D), and (c)(9)(iii) and (iv).
    The revisions read as follows:

[[Page 69242]]

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

    (a) 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, Sec.  63.2492, and 
Sec.  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. Sec.  63.987 or 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 [date 60 
days after date of publication of final rule in the Federal Register], 
you must comply with the requirements of this section and submit the 
test report. Beginning on and after [date 60 days after date of 
publication of final rule in the Federal Register], 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 FFFF, 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 FFFF 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.  [thinsp]63.1257(b)(8) instead 
of under normal operating conditions as specified in Sec.  
[thinsp]63.7(e)(1) or the conditions as specified in Sec.  
[thinsp]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 FFFF, 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 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 3 of 
this subpart; 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.  
63.2450(g), Sec.  63.997, 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 [date 60 days after date of publication of final rule in 
the Federal Register], 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 [date 60 days 
after date of publication of final rule in the Federal Register], 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.  
63.2450(g) and Sec.  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

[[Page 69243]]

according to the procedures in Sec.  63.2450(g) and Sec.  63.997. Use 
Method 29 of appendix A of 40 CFR part 60 to determine the HAP metals 
at the inlet and outlet of each control device, or use Method 5 of 
appendix A of 40 CFR part 60 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 paragraphs (a), (b), (c), and 
(e)(3) to read as follows:

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

    (a) 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), you must also meet each applicable requirement specified 
in paragraphs (c) through (e) of this section, Sec.  63.2492, and Sec.  
63.2493(a) through (c).
    (b) 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 63. (1) 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 63 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 
63, 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), 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 Sec.  
63.2550 do not apply for storage tanks in ethylene oxide service.
* * * * *
    (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.
* * * * *
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 paragraph (a), paragraph (b) introductory text, paragraphs 
(b)(1) and (2), and (b)(5);
0
b. Adding paragraphs (b)(6) and (7);
0
c. Revising paragraph (c) introductory text and paragraph (c)(5);
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.  63.2492 
and Sec.  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 subpart UU of this part 
63, 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 subpart 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 to pumps 
in light liquid service. Instead, for all pumps in light liquid service 
in an MCPU, the instrument reading that defines a leak and requires 
repair is 1,000 ppmv or greater.
    (7) For each piece of equipment that is added to an affected source 
after December 17, 2019, and for each piece of equipment that replaces 
equipment at an affected source after December 17, 2019, you must 
initially monitor for leaks within 30 days after initial startup of the 
equipment.
    (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).
* * * * *
    (10) Beginning no later than the compliance dates specified in 
Sec.  63.2445(h), paragraph (c)(5) of this section no longer applies to 
pumps in light liquid service. Instead, for all pumps in light liquid 
service in an MCPU, the instrument reading that defines a leak and 
requires repair is 1,000 ppmv or greater.
    (11) For each piece of equipment that is added to an affected 
source after December 17, 2019, and for each piece of equipment that 
replaces equipment at an affected source after December 17,

[[Page 69244]]

2019, you must initially monitor for leaks within 30 days after initial 
startup of the equipment.
* * * * *
    (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 subpart F. 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 all pressure relief devices.
    (1) Operating requirements. Except during a pressure release, 
operate each pressure relief device in organic HAP gas or vapor service 
with an instrument reading of less than 500 ppm above background as 
measured by the method in Sec.  63.1023(b) of subpart UU, Sec.  
63.180(c) of subpart H, or Sec.  65.104(b) of subpart F.
    (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 subpart F, 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 subpart F, 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 subpart F, 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

[[Page 69245]]

applicable requirements specified in Sec.  63.982(c)(2), Sec.  63.983, 
and Sec.  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 subpart F.
    (ii) Thermal expansion relief valves.
    (iii) Pressure relief devices designed with a set relief pressure 
of less than 2.5 psig.
    (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 [date 3 
years after date of publication of final rule in the Federal Register]. 
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, 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 (15) of this section do not apply when demonstrating compliance 
with this section.
    (1) Sec.  63.163(c)(3) of subpart H.
    (2) The second sentence of Sec.  63.181(d)(5)(i) of subpart H.
    (3) Sec.  63.1026(b)(3) of subpart UU.
    (4) The phrase ``(except periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1026(e)(1)(ii)(A) of subpart UU.
    (5) The phrase ``(except during periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1028(e)(1)(i)(A) of subpart UU.
    (6) The phrase ``(except during periods of startup, shutdown, or 
malfunction)'' from Sec.  63.1031(b)(1) of subpart UU.
    (7) The second sentence of Sec.  65.105(f)(4)(i) of subpart F.
    (8) Sec.  65.107(b)(3) of subpart F.
    (9) The phrase ``(except periods of start-up, shutdown, or 
malfunction)'' from Sec.  65.107(e)(1)(ii)(A) of subpart F.
    (10) The phrase ``(except during periods of start-up, shutdown, or 
malfunction)'' from Sec.  65.109(e)(1)(i)(A) of subpart F.
    (11) The phrase ``(except during periods of start-up, shutdown, or 
malfunction)'' from Sec.  65.112(b)(1) of subpart F.
    (12) The last sentence of Sec.  65.115(b)(1) of subpart F.
    (13) The last sentence of Sec.  65.115(b)(2) of subpart F.
    (14) 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 subpart G.
    (15) For flares complying with Sec.  63.2450(e)(5), the following 
provisions do not apply:
    (i) Sec.  63.172(d) of subpart H;
    (ii) Sec.  63.180(e) of subpart H;
    (iii) Sec.  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) Sec.  63.1034(b)(2)(iii) of subpart UU; and
    (vi) Sec.  65.115(b)(2) of subpart F.
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) introductory text, (n)(2) introductory text, 
(n)(2)(ii) and (n)(2)(iv)(A);
0
f. Redesignating Equation 1 to paragraph (n)(2) as Equation 4;
0
g. Adding paragraph (n)(2)(vii);
0
h. Revising paragraphs (n)(4) and (o);
0
i. Adding paragraphs (p) and (q).
    The revisions and additions read as follows:

[[Page 69246]]

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

    (a) 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.  [thinsp]63.172, the 
requirements of either Sec.  [thinsp]63.172 or Sec.  63.1034 apply for 
the purposes of this subpart.
* * * * *
    (h) * * *
    (4) As an alternative to using EPA Method 624 as specified in Sec.  
63.144(b)(5)(i)(C), you may use ASTM D5790-95 (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 (2012), then you 
must also use the sampling procedures of EPA Method 25D 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 63.2450(g)(6).
* * * * *
    (k) 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 4 of this subpart in accordance with the 
procedures described in paragraphs (n)(2)(i) through (viii) of this 
section. You have demonstrated initial compliance if E is greater than 
or equal to 90 percent.
* * * * *
    (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.  
[thinsp]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 4 of this subpart 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 
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 4 of this subpart.
    (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) Sec.  63.105(d) and (e).
    (2) Sec.  63.132(b)(3)(i)(B).
    (3) Sec.  63.132(f)(2).
    (4) Sec.  63.148(f)(3).
    (5) For flares complying with Sec.  63.2450(e)(5), the following 
provisions do not apply:
    (i) Sec.  63.139(c)(3);
    (ii) Sec.  63.139(d)(2)(vii)(3);
    (iii) Sec.  63.145(j);
    (iv) Sec.  63.146(b)(7)(i);
    (v) Sec.  63.147(d)(1); and
    (vi) Sec.  63.1034(b)(2)(iii).
0
13. Revise Sec.  63.2490 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 section'' 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) 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 hydrocarbon concentration (as methane) 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 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 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

[[Page 69247]]

hydrocarbon concentration (as methane) 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. 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'' Revision Number One, dated 
January 2003, Sampling Procedures Manual, appendix P: Cooling Tower 
Monitoring, prepared by Texas Commission on Environmental Quality, 
January 31, 2003 (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.
    (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. 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 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 
(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), (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 measured 
concentration 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 measured total strippable 
hydrocarbon concentration 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 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 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 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

[[Page 69248]]

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. 
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), (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, appendix A-1 and A-2, as 
appropriate.
    (5) The concentration of ethylene oxide must be determined using 
Method 18 of appendix A-6 of 40 CFR part 60 or Method 320 of appendix A 
to 40 CFR part 63.
    (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 or preparation by Method 5031 and analysis by 
Method 8260D in the SW-846 Compendium. In lieu of preparation by SW-846 
Method 5031, you may use SW-846 Method 5030B, 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.
    (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 an owner or operator demonstrates 
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 or preparation by Method 5031 and analysis by Method 8260D 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, 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) 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

[[Page 69249]]

requirement at the inlet and outlet of the control device.
    (ii) Conduct the performance test according to the procedures in 
Sec.  63.997 and Sec.  63.2450(g). Use Method 18 of appendix A-6 of 40 
CFR part 60 or Method 320 of appendix A to 40 CFR part 63 to determine 
the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 of 
40 CFR part 60 to select the sampling sites at each sampling location. 
Determine the gas volumetric flowrate using Method 2, 2A, 2C, or 2D of 
appendix A-2 of 40 CFR part 60. Use Method 4 of appendix A-3 of 40 CFR 
part 60 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 5 and 
6 of this subpart.
[GRAPHIC] [TIFF OMITTED] TP17DE19.002

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 7 of this subpart. You have demonstrated initial compliance if 
the overall reduction of ethylene oxide is greater than or equal to 
99.9 percent by weight.

[GRAPHIC] [TIFF OMITTED] TP17DE19.003

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 5 and 6 
of this subpart.

    (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 (E) 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.
    (C) Pressure drop of the scrubber column. Determine the average 
pressure drop during the performance test as the average of the test 
run averages.
    (D) 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.
    (E) Liquid feed pressure to the wet scrubber column. Determine the 
average liquid feed pressure 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 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.  63.997 and Sec.  63.2450(g). Use Method 18 of appendix A-6 of 40 
CFR part 60 or Method 320 of appendix A to 40 CFR part 63 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

[[Page 69250]]

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.  63.997 and Sec.  63.2450(g). Use Method 18 of appendix A-6 of 40 
CFR part 60 or Method 320 of appendix A to 40 CFR part 63 to determine 
the ethylene oxide concentration. Use Method 1 or 1A of appendix A-1 of 
40 CFR part 60 to select the sampling site. Determine the gas 
volumetric flowrate using Method 2, 2A, 2C, or 2D of appendix A-2 of 40 
CFR part 60. Use Method 4 of appendix A-3 of 40 CFR part 60 to convert 
the volumetric flowrate to a dry basis.
    (iii) Calculate the mass emission rate of ethylene oxide exiting 
the control device using Equation 6 of this subpart. 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) 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 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.
    (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 an instantaneous 
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 an instantaneous basis. Use a pH sensor with a minimum 
accuracy of 0.2 pH units.
    (iii) Maximum pressure drop across the scrubber column, equal to 
the average pressure drop measured during the most recent performance 
test. Compliance with the pressure drop operating limit must be 
determined continuously on an instantaneous 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 an instantaneous basis. Use a 
temperature sensor with a minimum accuracy of 1 percent 
over the normal range of the temperature measured, expressed in degrees 
Celsius, or 2.8 degrees Celsius, whichever is greater.
    (v) Minimum liquid feed pressure to the scrubber column, equal to 
the average feed pressure measured during the most recent performance 
test. Compliance with the liquid feed pressure operating limit must be 
determined continuously on an instantaneous 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 an instantaneous 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 an instantaneous 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.

[[Page 69251]]

    (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).

Option 1 for Paragraph (d)

    (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 subpart H of this part 63, 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 not vent 
directly to atmosphere.

Option 2 for Paragraph (d)

    (d) Equipment in ethylene oxide service. Except as specified in 
paragraphs (d)(1) through (5) 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 subpart H of this part 63, or 40 
CFR part 65, subpart F.
    (1) Except as specified in paragraph (d)(3) of this section, 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) Except as specified in paragraph (d)(3) of this section, 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) If you operate an MCPU at the facility commonly called Huntsman 
Performance at 5451 Jefferson Chemical Road in Conroe, Texas or Lanxess 
Corporation at 2151 King Street Extension in Charleston, SC, then you 
must comply with the requirements in paragraphs (d)(3)(i) and (ii) of 
this section in lieu of the requirements specified in paragraphs (d)(1) 
and (2) of this section.
    (i) For pumps and valves in ethylene oxide service, you must comply 
with the requirements in paragraphs (d)(3)(i)(A) through (E) of this 
section.
    (A) You must install and operate leakless pumps as defined in Sec.  
63.2550(i), and monitor the pumps annually.
    (B) You must comply with either paragraph (d)(3)(i)(B)(1) or (2) 
for valves.
    (1) Install and operate a leakless valve as defined in Sec.  
63.2550(i) and monitor the valve annually or
    (2) Operate any valve that is not considered a leakless valve as 
defined in Sec.  63.2550(i) and monitor the valve quarterly.
    (C) Valves and pumps must be monitored using the methods specified 
in Sec.  63.180(b) and (c), Sec.  63.1023(b) and (c), or Sec.  
65.104(b) and (c).
    (D) For valves and pumps, the instrument reading that defines a 
leak is any value above the measured background concentration.
    (E) When a leak is detected, it must be repaired as soon as 
practicable, but not later than 15 calendar days after the leak is 
detected. A first attempt at repair must be made no later than 5 
calendar days after the leak is detected. Following repair, the valve 
or pump must be returned to operation as required in paragraphs 
(d)(3)(i)(A) through (D) of this section.
    (ii) For connectors in ethylene oxide service, you must comply with 
the requirements in paragraphs (d)(3)(ii)(A) through (C) of this 
section.
    (A) The instrument reading that defines a leak for connectors is 
100 parts per million or greater.
    (B) The monitoring period for connectors is once every month.
    (C) When a leak is detected, it must be repaired as soon as 
practicable, but not later than 15 calendar days after the leak is 
detected. A first attempt at repair must be made no later than 5 
calendar days after the leak is detected. Following repair, the 
connector must be returned to operation as required in paragraphs 
(d)(3)(ii)(A) and (B) of this section.
    (4) For each light liquid pump, valve, or connector in ethylene 
oxide service that is added to an affected source, and for each light 
liquid pump, valve, or connector in ethylene oxide service that 
replaces a light liquid pump, valve, or connector in ethylene oxide 
service, you must initially monitor for leaks within 5 days after 
initial startup of the equipment.
    (5) Pressure relief devices in ethylene oxide service must not vent 
directly to atmosphere.
    (e) The referenced provisions specified in paragraphs (e)(1) 
through (15) of this section do not apply when demonstrating compliance 
with this section.
    (1) Sec.  63.163(c)(3) of subpart H.
    (2) Sec.  63.163(e) of subpart H.
    (3) The second sentence of Sec.  63.181(d)(5)(i) of subpart H.
    (4) Sec.  63.1026(b)(3) of subpart UU.

[[Page 69252]]

    (5) Sec.  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 subpart F.
    (9) Sec.  65.107(b)(3) of subpart F.
    (10) Sec.  65.107(e) of subpart F.
    (11) The phrase (except during periods of start-up, shutdown, or 
malfunction)'' from Sec.  65.109(e)(1)(i)(A) of subpart F.
    (12) The phrase (except during periods of start-up, shutdown, or 
malfunction)'' from Sec.  65.112(b)(1) of subpart F.
    (13) The last sentence of Sec.  65.115(b)(1) of subpart F.
    (14) The last sentence of Sec.  65.115(b)(2) of subpart F.
    (15) For flares complying with Sec.  63.2450(e)(5), the following 
provisions do not apply:
    (i) Sec.  63.172(d);
    (ii) Sec.  63.180(e);
    (iii) Sec.  63.181(g)(1)(iii);
    (iv) The phrase ``including periods when a flare pilot light system 
does not have a flame'' from Sec.  63.181(g)(2)(i);
    (v) Sec.  63.1034(b)(2)(iii); and
    (vi) Sec.  65.115(b)(2).
    (16) Requirements for maintenance vents in Sec.  63.2455(d).
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 of 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 the requirements in Sec.  63.983 and the requirements referenced 
therein for closed-vent systems.
* * * * *
    (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) 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), (f)(4) and (6), and 63.9(b) through (h) 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) of this section.
0
20. Section 63.2520 is amended by:
0
a. Revising paragraph (c) introductory text and paragraph (c)(2);
0
b. Adding paragraph (c)(8);
0
c. Revising paragraphs (d) introductory text and paragraph (d)(2)(ii);
0
d. Adding paragraphs (d)(3) through (5);
0
e. Revising paragraph (e) introductory text, paragraphs (e)(2) through 
(4), paragraph (e)(5)(ii) introductory text, and paragraph 
(e)(5)(ii)(A) and (B);
0
f. Adding paragraph (e)(5)(ii)(D);
0
g. Revising paragraph (e)(5)(iii) introductory text, paragraph 
(e)(5)(iii)(A) through(F), and (e)(5)(iii)(I);
0
h. Adding paragraphs (e)(5)(iii)(M) and (N);
0
i. Revising paragraphs (e)(7) and (8);
0
j. 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.
    (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 69253]]

    (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 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 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 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 subpart H of this part 63, or 40 CFR part 65, 
subpart F), and the information specified in paragraphs (d)(5)(A) 
through (C) of this section.
    (A) For process vents, include all uncontrolled, undiluted ethylene 
oxide concentration measurements, and the calculations you used to 
determine the total uncontrolled, undiluted ethylene oxide mass 
emission rate for the sum of all vent gas streams.
    (B) For storage tanks, include the concentration of ethylene oxide 
of the fluid stored in each storage tank.
    (C) For equipment, include the percent ethylene oxide content of 
the process fluid and the method used to determine it, and identify the 
location of each leakless pump and valve in operation.
    (e) Compliance report. The compliance report must contain the 
information specified in paragraphs (e)(1) through (17) of this 
section. On and after [date three years after date of publication of 
final rule in the Federal Register], 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/). 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 report must be 
submitted by the deadline specified in this subpart, regardless of the 
method in which the report is submitted. If you claim some of the 
information required to be submitted via CEDRI is CBI, 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. 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 earlier in 
this paragraph.
* * * * *
    (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 this 
requirement.
    (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 [date 
3 years after date of publication of final rule in the Federal 
Register], this paragraph no longer applies; however, for historical 
compliance purposes, a copy of the plan must be retained and available 
on-site for five years after [date 3 years after date of publication of 
final rule in the Federal Register].
    (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,

[[Page 69254]]

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, 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).
* * * * *
    (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 
information required in Sec.  63.999(c)(3) of subpart SS.
    (i) Records as specified in Sec.  63.2525(m)(1) of this section 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 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.  63.670(o)(3) 
of subpart CC:
    (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 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

[[Page 69255]]

requirements in Sec.  63.2450(e)(7), you must report 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.  63.2455(d)(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.  63.2455(d)(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.  63.2455(d)(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)(2)(i), report the dates for all 
instrument 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)(ii), report the dates of 
instrument monitoring conducted.
    (iii) For pressure relief devices in organic HAP service subject to 
Sec.  63.2480(e)(2)(iii), report each pressure release to the 
atmosphere, including the start date, start time, and duration of the 
pressure release and 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, beginning no later than the 
compliance dates specified in 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).
    (ii) The number of heat exchange systems at the plant site found to 
be leaking.
    (iii) For each monitoring location where the total strippable 
hydrocarbon concentration was determined to be equal to or greater than 
the applicable leak definitions specified in Sec.  63.2490(d)(1)(v), 
identification of the monitoring location (e.g., unique monitoring 
location or heat exchange system ID number), the measured total 
strippable hydrocarbon concentration in ppmv as methane, 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 in ppmv as methane 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 in ppmv as methane and 
date of each monitoring event conducted on the delayed repair during 
the reporting period, and an estimate in pounds of the potential 
strippable 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 [date 60 days 
after date of publication of final rule in the Federal Register], you 
must submit performance test reports in accordance with this paragraph. 
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). If you claim some of 
the information submitted under paragraphs (f)(1) and (2) of this 
section is CBI, 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

[[Page 69256]]

be submitted to the EPA via the EPA's CDX as described in paragraph 
(f)(1) and (2) of this section.
    (g) Performance evaluation reports. Beginning no later than [date 
60 days after date of publication of final rule in the Federal 
Register], you must start submitting performance evaluation reports in 
accordance with this paragraph. 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 relative accuracy test 
audit (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). If you claim some of 
the information submitted under paragraphs (g)(1) and (2) of this 
section is CBI, 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.
    (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 
the 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 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) 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.
    (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 the 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, 
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) 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.  63.2450(e)(4), Sec.  63.2480(f), 
Sec.  63.2485(p) and (q), and paragraph (t) of this section, each 
applicable record required by subpart A of this part 63 and in 
referenced subparts F, G, SS, UU, WW, and GGG of this part 63 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. Sec.  63.987 or 63.2450(e)(5), as 
applicable.
* * * * *

[[Page 69257]]

    (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), 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 [date 3 years after date of publication of final rule in the 
Federal Register], this paragraph 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).
    (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 (15) of this section in lieu of the information required in 
Sec.  63.998(a)(1) of subpart SS.
    (1) Retain records of the output of the monitoring device used to 
detect the presence of a pilot flame as required in Sec.  63.670(b) of 
subpart CC and Sec.  63.2450(e)(5)(vii)(D) for a minimum of 2 years. 
Retain records of each 15-minute block during which there was at least 
one minute that no pilot flame 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.
    (2) Retain records of daily visible emissions observations or video 
surveillance images required in Sec.  63.670(h) of subpart CC 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 at 40 CFR part 60, appendix A-7, then the record must identify 
whether the visible emissions observation was performed, the results of 
each observation, total duration of observed visible emissions, and 
whether it was a 5-minute or 2-hour observation. Record the date and 
start time of each visible emissions observation.
    (iii) If a video surveillance camera is used, 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.  63.670(d) through (f) of 
subpart CC and Sec.  63.2450(e)(5)(vii) 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.  63.670(o)(3) of subpart CC, 
including an

[[Page 69258]]

identification of the affected flare, the date and duration of the 
event, a statement noting whether the event resulted from the same root 
cause(s) identified in a previous analysis and either a description of 
the recommended corrective action(s) or an explanation of why 
corrective action is not necessary under Sec.  63.670(o)(5)(i) of 
subpart CC.
    (14) For any corrective action analysis for which implementation of 
corrective actions are required in Sec.  63.670(o)(5) of subpart CC, a 
description of the corrective action(s) completed within the first 45 
days following the discharge and, for action(s) not already completed, 
a schedule for implementation, including proposed commencement and 
completion dates.
    (15) Records described in Sec.  63.10(b)(2)(vi) and (xi).
    (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 (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 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.  63.2455(d), you must keep the applicable records specified in 
(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.  63.2455(d). 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.  63.2455(d))(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.  63.2455(d)(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 
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.  63.2455(d)(1)(iii), 
records used to estimate 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 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, identification of 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.  63.2455(d)(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 five 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 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.

[[Page 69259]]

    (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 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 strippable 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 (D) of this section.
    (A) Determine the leak concentration as specified in Sec.  
63.2490(d) and convert 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'' Revision Number One, dated January 2003, 
Sampling Procedures Manual, appendix P: Cooling Tower Monitoring, 
prepared by Texas Commission on Environmental Quality, January 31, 2003 
(incorporated by reference--see Sec.  63.14) and the molecular weight 
of 16 grams per mole (g/mol) for methane.
    (B) Determine 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. Volumetric 
flow measurements may be used and converted to mass flow rates using 
the density of water at the specific monitoring location temperature or 
using the default density of water at 25 degrees Celsius, which is 997 
kilograms per cubic meter or 8.32 pounds per gallon.
    (C) For delay of repair monitoring intervals prior to repair of the 
leak, calculate the potential strippable hydrocarbon emissions for the 
leaking heat exchange system or heat exchanger for the monitoring 
interval by multiplying the leak concentration in the cooling water, 
ppmw, determined in (r)(4)(iv)(A) of this section, by the mass flow 
rate of the cooling water determined in (r)(4)(iv)(B) of this section 
and 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.
    (D) For delay of repair monitoring intervals ending with a repaired 
leak, calculate the potential strippable 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 leak concentration and 
cooling water flow rates determined for the last monitoring event prior 
to the re-monitoring event used to verify the leak was repaired. The 
duration of the final delay of repair monitoring interval is the time 
period starting at midnight of the day of the last monitoring event 
prior to re-monitoring to verify the leak was repaired and ending at 
the time of the re-monitoring event that verified that the leak was 
repaired.
    (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, undiluted 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, and records 
identifying the location of each leakless pump and valve in operation.
    (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) Sec.  63.103(c)(2)(i) of subpart F.
    (2) Sec.  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) Sec.  63.152(g)(2)(iv)(A) of subpart G.
0
22. Section 63.2535 is amended by revising the introductory text and 
paragraph (d) and adding paragraph (m) to read as follows:

[[Page 69260]]

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. Sec.  63.2445(g), 63.2450(e)(5) or 63.2493 but subject 
to other provisions of both this subpart and another rule, 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 63. 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 63, you may elect to comply with the provisions of subpart H, 
GGG, or MMM of this part 63, respectively, for all such equipment, 
except the affirmative defense requirements in subparts GGG and MMM no 
longer apply.
* * * * *
    (m) Overlap of subpart FFFF with other regulations for flares. 
Beginning no later than the compliance dates specified in Sec.  
63.2445(g), flares that control ethylene oxide emissions or are used to 
control emissions from processes that produce olefins and polyolefins, 
subject to the provisions of 40 CFR 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 through 7 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.
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 40 CFR part 63, 
subpart E, 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. In Sec.  63.2550 amend paragraph (i) by:
0
a. Revising paragraph (4) in the definition of ``Batch process vent'';
0
b. Adding, in alphabetical order, new definitions for ``Bench-scale 
process'' and ``Breakthrough'';
0
c. Adding paragraphs (8) and (9) 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'', ``Leakless 
pump'', ``Leakless valve'', ``Loading rack'';
0
f. Revising paragraph (6) in the definition of ``Miscellaneous organic 
chemical manufacturing process''; and
0
g. Adding definitions, in alphabetical order, for ``Pressure release'', 
``Pressure relief device'', ``Pressure vessel'', and ``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 [date 3 years after date of publication of final rule in the 
Federal Register], 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;
* * * * *
    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 detected 
is at the highest concentration allowed to be discharged from an 
adsorber system.
* * * * *
    Continuous process vent * * *
    (8) On and after [date 3 years after date of publication of final 
rule in the Federal Register], 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 [date 3 years after date of publication of final 
rule in the Federal Register], 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 this section, 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) 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.
* * * * *
    Deviation * * *
    (3) Before [date 3 years after date of publication of final rule in 
the Federal Register], fails to meet any emission limit, operating 
limit, or work practice standard in this subpart during startup, 
shutdown, or malfunction, regardless of whether or not such failure is 
permitted by this subpart. On and after [date 3 years after date of 
publication of final rule in the Federal Register], this paragraph 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

[[Page 69261]]

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 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). 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 with a concentration of ethylene oxide 
greater than or equal to 1 ppmw. 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.
* * * * *
    Leakless pump means a pump that has no externally actuated shaft 
penetrating the pump housing, and as such, is designed to operate with 
no instrument readings above the background concentration level, as 
demonstrated using Method 21 of 40 CFR part 60, appendix A-7. Examples 
of leakless pumps include diaphragm pumps, magnetically-driven pumps, 
and canned motor pumps. A pump equipped with a dual mechanical seal 
system that includes a barrier fluid system with a higher pressure than 
the process is also considered a leakless pump.
    Leakless valve means a valve that has no external actuating 
mechanism in contact with the process fluid, and as such, is designed 
to operate with no instrument readings above the background 
concentration level, as demonstrated using Method 21 of 40 CFR part 60, 
appendix A-7. Examples of leakless valves include bellows valves which 
are gate or globe valves that use a cylindrical metal bellows to 
hermetically seal the valve against stem leakage.
    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.
    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 69262]]

    Relief valve means a type of pressure relief device that is 
designed to re-close after the pressure relief.
* * * * *
0
25. Table 1 to subpart FFFF of part 63 is revised to read as follows:

  Table 1 to Subpart FFFF of Part 63--Emission Limits and Work Practice
                 Standards for Continuous Process Vents
  [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]
------------------------------------------------------------------------
       For each . . .            For which . . .     Then you must . . .
------------------------------------------------------------------------
1. Group 1 continuous         a. Not applicable...  i. Reduce emissions
 process vent.                                       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        a. You use a          i. Use a halogen
 continuous process vent       combustion control    reduction device
 stream.                       device to control     after the
                               organic HAP           combustion device
                               emissions.            to reduce emissions
                                                     of 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         You use a recovery    Comply with the
 process vent at an existing   device to maintain    requirements in
 source.                       the TRE level >1.9    Sec.
                               but <=5.0.            63.2450(e)(4) and
                                                     the requirements in
                                                     Sec.   63.993 and
                                                     the requirements
                                                     referenced therein.
4. Group 2 continuous         You use a recovery    Comply with the
 process vent at a new         device to maintain    requirements in
 source.                       the TRE level >5.0    Sec.
                               but <=8.0.            63.2450(e)(4) and
                                                     the requirements in
                                                     Sec.   63.993 and
                                                     the requirements
                                                     referenced therein.
5. Continuous process vent..  Beginning no later    Comply with the
                               than the compliance   applicable emission
                               dates specified in    limits specified in
                               Sec.   63.2445(i),    items 1 through 4
                               the continuous        of this Table, and
                               process vent          also:
                               contains ethylene    i. Reduce emissions
                               oxide such that it    of ethylene oxide
                               is considered to be   by venting
                               in ethylene oxide     emissions through a
                               service as defined    closed-vent system
                               in Sec.   63.2550.    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
26. Table 2 to subpart FFFF of part 63 is amended by adding a new entry 
3 to read as follows:

[[Page 69263]]

     Table 2 to Subpart FFFF of Part 63--Emission Limits and Work Practice Standards for Batch Process Vents
  [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]
----------------------------------------------------------------------------------------------------------------
            For each . . .                         Then you must . . .                   And you must . . .
----------------------------------------------------------------------------------------------------------------
1. Process with Group 1 batch process  a. Reduce collective uncontrolled organic   Not applicable.
 vents.                                 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 organic   Not applicable.
                                        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
                                       c. Reduce uncontrolled organic HAP          For all other batch process
                                        emissions from one or more batch process    vents within the process,
                                        vents within the process by venting         reduce collective organic
                                        through a closed-vent system to a flare     HAP emissions as specified
                                        or by venting through one or more closed-   in item 1.a and/or item 1.b
                                        vent systems to any combination of          of this table.
                                        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 process   a. Use a halogen reduction device after     i. Reduce overall emissions
 vent for which you use a combustion    the combustion control device; or           of hydrogen halide and
 device to control organic HAP                                                      halogen HAP by >=99 percent;
 emissions.                                                                         or
                                                                                   ii. Reduce overall emissions
                                                                                    of hydrogen 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
                                        the combustion control device.              emission rate to <=0.45 kg/
                                                                                    hr or to a concentration
                                                                                    <=20 ppmv.
3. Batch process vent that contains    Beginning no later than the compliance      Not applicable.
 ethylene oxide such that it is         dates specified in Sec.   63.2445(i),
 considered to be in ethylene oxide     comply with the applicable emission
 service as defined in Sec.   63.2550.  limits specified in items 1 and 2 of this
                                        Table, and also:
                                          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:

[[Page 69264]]

  Table 4 to Subpart FFFF of Part 63--Emission Limits for Storage Tanks
[As required in Sec.   63.2470, you must meet each emission limit in the
           following table that applies to your storage tanks]
------------------------------------------------------------------------
       For each . . .            For which . . .     Then you must . . .
------------------------------------------------------------------------
1. Group 1 storage tank.....  a. The maximum true   i. Reduce total HAP
                               vapor pressure of     emissions by >=95
                               total HAP at the      percent by weight
                               storage temperature   or to <=20 ppmv of
                               is >=76.6             TOC or organic HAP
                               kilopascals.          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
                                                    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.\a\
                              b. The maximum true   i. Comply with the
                               vapor pressure of     requirements of
                               total HAP at the      subpart WW of this
                               storage temperature   part, except as
                               is <76.6              specified in Sec.
                               kilopascals.          63.2470; or
                                                    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.\a\
2. Halogenated vent stream    You use a combustion  Meet one of the
 from a Group 1 storage tank.  control device to     emission limit
                               control organic HAP   options specified
                               emissions.            in Item 2.a.i or
                                                     ii. in Table 1 to
                                                     this subpart.
3. Storage tank of any        Beginning no later    Comply with the
 capacity and vapor pressure.  than the compliance   applicable emission
                               dates specified in    limits specified in
                               Sec.   63.2445(i),    items 1 and 2 of
                               the stored liquid     this Table, and
                               contains ethylene     also:
                               oxide such that the  i. Reduce emissions
                               storage tank is       of ethylene oxide
                               considered to be in   by venting
                               ethylene oxide        emissions through a
                               service as defined    closed-vent system
                               in Sec.   63.2550.    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
                                                        storage tank
                                                        vent.
------------------------------------------------------------------------
\a\ 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, must be in compliance with Sec.
  63.2450(e)(5).

0
28. Table 5 to subpart FFFF of part 63 is revised to read as follows:

  Table 5 to Subpart FFFF of Part 63--Emission Limits and Work Practice
                      Standards for Transfer Racks
  [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]
------------------------------------------------------------------------
             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

[[Page 69265]]

 
                                         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; \a\ 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 transfer rack     a. Use a halogen reduction
 vent stream for which you use a          device after the combustion
 combustion device to control organic     device to reduce emissions of
 HAP emissions.                           hydrogen halide and halogen
                                          HAP by >=99 percent by weight,
                                          to <=0.45 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.
------------------------------------------------------------------------
\a\ 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, must be in compliance with Sec.
  63.2450(e)(5).

0
29. Table 6 to subpart FFFF of part 63 is revised to read as follows:

  Table 6 to Subpart FFFF of Part 63--Requirements for Equipment Leaks
  [As required in Sec.   63.2480, you must meet each requirement in the
          following table that applies to your equipment leaks]
------------------------------------------------------------------------
                               And that is part of
        For all . . .                 . . .            You must . . .
------------------------------------------------------------------------
1. Equipment that is in       a. Any MCPU.........  i. Comply with the
 organic HAP service.                                requirements of
                                                     subpart UU of this
                                                     part 63 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 63 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       a. Any MCPU.........  i. Comply with the
 organic HAP service at a                            requirements of
 new source.                                         subpart UU of this
                                                     part 63 and the
                                                     requirements
                                                     referenced therein,
                                                     except as specified
                                                     in Sec.
                                                     63.2480(b)(6),
                                                     (b)(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),
                                                     (c)(11), (e), and
                                                     (f).
3. Equipment that is in       a. Any MCPU.........  i. Beginning no
 ethylene oxide service as                           later than the
 defined in Sec.   63.2550.                          compliance dates
                                                     specified in Sec.
                                                     63.2445(i), comply
                                                     with the
                                                     requirements of
                                                     subpart UU of this
                                                     part 63 and the
                                                     requirements
                                                     referenced therein,
                                                     except as specified
                                                     in Sec.
                                                     63.2493(d) and (e);
                                                     or
                                                    ii. Beginning no
                                                     later than the
                                                     compliance dates
                                                     specified in Sec.
                                                     63.2445(i), comply
                                                     with the
                                                     requirements of
                                                     subpart H of this
                                                     part 63 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).
------------------------------------------------------------------------

[[Page 69266]]

0
30. Table 10 to subpart FFFF of part 63 is revised to read as follows:

  Table 10 to Subpart FFFF of Part 63--Work Practice Standards for Heat
                            Exchange Systems
  [As required in Sec.   63.2490, you must meet each requirement in the
       following table that applies to your heat exchange systems]
------------------------------------------------------------------------
             For each . . .                       You must . . .
------------------------------------------------------------------------
Heat exchange system, as defined in      a. Comply with the requirements
 Sec.   63.101.                           of Sec.   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:

Table 12 to Subpart FFFF of Part 63--Applicability of General Provisions
                             to Subpart FFFF
  [As specified in Sec.   63.2540, the parts of the General Provisions
           that apply to you are shown in the following table]
------------------------------------------------------------------------
           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   Yes.
                                 for New and
                                 Reconstructed
                                 sources.
Sec.   63.6(b)(5).............  Notification.....  Yes.
Sec.   63.6(b) (6)............  [Reserved].......  .....................
Sec.   63.6(b)(7).............  Compliance Dates   Yes.
                                 for New and
                                 Reconstructed
                                 Area Sources
                                 That Become
                                 Major.
Sec.   63.6(c)(1)-(2).........  Compliance Dates   Yes.
                                 for Existing
                                 Sources.
Sec.   63.6(c)(3)-(4).........  [Reserved].......  .....................
Sec.   63.6(c)(5).............  Compliance Dates   Yes.
                                 for Existing
                                 Area Sources
                                 That Become
                                 Major.
Sec.   63.6(d)................  [Reserved].......  .....................
Sec.   63.6(e)(1)(i)..........  Operation &        Yes, before [date 3
                                 Maintenance.       years after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. See Sec.
                                                     63.2450(u) for
                                                    general duty
                                                    requirement.
Sec.   63.6(e)(1)(ii).........  Operation &        Yes, before [date 3
                                 Maintenance.       years after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.6(e)(1)(iii)........  Operation &        Yes.
                                 Maintenance.
Sec.   63.6(e)(2).............  [Reserved].......  .....................
Sec.   63.6(e)(3)(i), (ii),     Startup,           Yes, before [date 3
 and (v) through (viii).         Shutdown,          years after date of
                                 Malfunction Plan   publication of final
                                 (SSMP).            rule in the Federal
                                                    Register], except
                                                    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 [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
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               Yes, before [date 3
                                 incorporation      years after date of
                                 into title V       publication of final
                                 permit.            rule in the Federal
                                                    Register]. No
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.6(f)(1).............  Compliance Except  Yes, before [date 3
                                 During SSM.        years after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.6(f)(2)-(3).........  Methods for        Yes.
                                 Determining
                                 Compliance.
Sec.   63.6(g)(1)-(3).........  Alternative        Yes.
                                 Standard.
Sec.   63.6(h)(1).............  Compliance with    Yes, before [date 3
                                 Opacity/VE         years after date of
                                 Standards.         publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.6(h)(2)-(9).........  Opacity/Visible    Only for flares for
                                 Emission (VE)      which Method 22
                                 Standards.         observations are
                                                    required as part of
                                                    a flare compliance
                                                    assessment.
Sec.   63.6(i)(1)-(14)........  Compliance         Yes.
                                 Extension.
Sec.   63.6(j)................  Presidential       Yes.
                                 Compliance
                                 Exemption.

[[Page 69267]]

 
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(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            Yes.
                                 Facilities.
Sec.   63.7(e)(1).............  Conditions for     Yes, before [date 3
                                 Conducting         years after date of
                                 Performance        publication of final
                                 Tests.             rule in the Federal
                                                    Register] except
                                                    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 [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. 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           Yes.
                                 Effluents 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 [date 3
                                 Predictable SSM.   years after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.8(c)(1)(ii).........  SSM not in SSMP..  Yes, before [date 3
                                                    years after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.8(c)(1)(iii)........  Compliance with    Yes, before [date 3
                                 Operation and      years after date of
                                 Maintenance        publication of final
                                 Requirements.      rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
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
                                                    part 63.
                                                    Requirements for
                                                    COMS do not apply
                                                    because subpart FFFF
                                                    does not require
                                                    continuous opacity
                                                    monitoring systems
                                                    (COMS).
Sec.   63.8(c)(4)(i)..........  COMS Measurement   No; subpart FFFF does
                                 and Recording      not require COMS.
                                 Frequency.
Sec.   63.8(c)(4)(ii).........  CEMS Measurement   Yes.
                                 and Recording
                                 Frequency.
Sec.   63.8(c)(5).............  COMS Minimum       No. Subpart FFFF does
                                 Procedures.        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 63.
                                                    Requirements for
                                                    COMS do not apply
                                                    because subpart FFFF
                                                    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
                                                    part 63.
                                                    Requirements for
                                                    COMS do not apply
                                                    because subpart FFFF
                                                    does not require
                                                    COMS.
Sec.   63.8(d)(1).............  CMS Quality        Only for CEMS.
                                 Control.
Sec.   63.8(d)(2).............  CMS Quality        Only for CEMS.
                                 Control.
Sec.   63.8(d)(3).............  CMS Quality        Yes, only for CEMS
                                 Control.           before [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. See Sec.
                                                     63.2450(j)(6).
Sec.   63.8(e)................  CMS Performance    Only for CEMS, except
                                 Evaluation.        this subpart
                                                    specifies how and
                                                    when the performance
                                                    evaluation results
                                                    are reported.
                                                    Section
                                                    63.8(e)(5)(ii) does
                                                    not apply because
                                                    subpart FFFF does
                                                    not require COMS.
Sec.   63.8(f)(1)-(5).........  Alternative        Yes, except you may
                                 Monitoring         also request
                                 Method.            approval using the
                                                    precompliance
                                                    report.

[[Page 69268]]

 
Sec.   63.8(f)(6).............  Alternative to     Only applicable when
                                 Relative           using CEMS to
                                 Accuracy Test.     demonstrate
                                                    compliance,
                                                    including the
                                                    alternative standard
                                                    in Sec.   63.2505.
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 subpart FFFF
                                                    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 63.
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    No.
                                 VE/Opacity Test.
Sec.   63.9(g)................  Additional         Only for CEMS.
                                 Notifications      Section 63.9(g)(2)
                                 When Using CMS.    does not apply
                                                    because subpart FFFF
                                                    does not require
                                                    COMS.
Sec.   63.9(h)(1)-(6).........  Notification of    Yes, except
                                 Compliance         63.9(h)(2)(i)(A)
                                 Status.            through (G) and (ii)
                                                    do not apply because
                                                    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          No, Sec.   63.2520(e)
                                 Previous           specifies reporting
                                 Information.       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    No, see Sec.  Sec.
                                 to SS.             63.2450(e) and
                                                    63.2525 for
                                                    recordkeeping
                                                    requirements.
Sec.   63.10(b)(2)(ii)........  Recordkeeping      Yes, before [date 3
                                 relevant to SSM    years after date of
                                 periods and CMS.   publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register]. See Sec.
                                                    Sec.   63.2525(h)
                                                    and 63.2525(l).
Sec.   63.10(b)(2)(iii).......  Records related    Yes.
                                 to maintenance
                                 of air pollution
                                 control
                                 equipment.
Sec.   63.10(b)(2)(iv)........  Recordkeeping      Yes, before [date 3
                                 relevant to SSM    years after date of
                                 periods and CMS.   publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.10(b)(2)(v).........  Recordkeeping      Yes, before [date 3
                                 relevant to SSM    years after date of
                                 periods and CMS.   publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.10(b)(2)(vi), (x),    CMS Records......  Only for CEMS;
 and (xi).                                          requirements for
                                                    CPMS are specified
                                                    in referenced
                                                    subparts G and SS of
                                                    this part 63.
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 63.
Sec.   63.10(c)(7)-(8)........  Records..........  No. Recordkeeping
                                                    requirements are
                                                    specified in Sec.
                                                    63.2525.
Sec.   63.10(c)(15)...........  Records..........  Yes, before [date 3
                                                    years after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register], but only
                                                    for CEMS. No,
                                                    beginning on and
                                                    after [date 3 years
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.10(d)(1)............  General Reporting  Yes.
                                 Requirements.
Sec.   63.10(d)(2)............  Report of          Yes, before [date 60
                                 Performance Test   days after date of
                                 Results.           publication of final
                                                    rule in the Federal
                                                    Register]. No,
                                                    beginning on and
                                                    after [date 60 days
                                                    after date of
                                                    publication of final
                                                    rule in the Federal
                                                    Register].
Sec.   63.10(d)(3)............  Reporting Opacity  No.
                                 or 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        (5) specify the SSM
                                 Reports.           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, except
                                 Reports.           this subpart
                                                    specifies how and
                                                    when the performance
                                                    evaluation results
                                                    are reported.
Sec.   63.10(e)(2)(ii)........  Additional COMS    No. Subpart FFFF does
                                 Reports.           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.

[[Page 69269]]

 
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)-(viii).  Excess Emissions   No. Reporting
                                 Report and         requirements are
                                 Summary Report.    specified in Sec.
                                                    63.2520.
Sec.   63.10(e)(4)............  Reporting COMS     No.
                                 data.
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.
------------------------------------------------------------------------

[FR Doc. 2019-24573 Filed 12-16-19; 8:45 am]
 BILLING CODE 6560-50-P