[Federal Register Volume 85, Number 217 (Monday, November 9, 2020)]
[Proposed Rules]
[Pages 71490-71528]
[FR Doc No: 2020-23387]

Vol. 85

Monday,

No. 217

November 9, 2020

Part III

 Environmental Protection Agency

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40 CFR Part 63

 National Emission Standards for Hazardous Air Pollutants: Polyvinyl
Chloride and Copolymers Production Reconsideration; Proposed Rule

Federal Register / Vol. 85 , No. 217 / Monday, November 9, 2020 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2002-0037; FRL-10015-41-OAR]
RIN 2060-AR73

National Emission Standards for Hazardous Air Pollutants:
Polyvinyl Chloride and Copolymers Production Reconsideration

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule; reconsideration of final rule.

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SUMMARY: On April 17, 2012, the U.S. Environmental Protection Agency
(EPA) promulgated National Emission Standards for Hazardous Air
Pollutants (NESHAP) for Polyvinyl Chloride and Copolymers (PVC)
Production at major and area sources. Subsequently, the Administrator
received and granted petitions for reconsideration of the emission
limits in the 2012 final rules for process vents, process wastewater,
and stripped resin for major and area sources. In response to the
petitions and after gathering additional information from PVC
companies, the EPA is proposing revisions to emission limits in the
2012 major source rule for process vents and process wastewater.
Although the EPA is not proposing revisions to emission limits in the
2012 area source rule, the EPA is proposing other amendments that
affect both rules, including technical corrections and clarifications
related to the standards for stripped resin, storage vessels (including
the use of vapor balancing), equipment leaks, and closed vent systems.
The EPA is also proposing to clarify text and correct typographical
errors, grammatical errors, and cross-reference errors in both rules.
In addition, the EPA is proposing to remove the affirmative defense
provisions. We estimate that, if finalized, these proposed amendments
would result in hazardous air pollutants (HAP) emissions reductions of
34 tons per year (tpy) with an annualized cost of $0.39 million.

DATES: Comments must be received on or before January 8, 2021. 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 December 9, 2020.
    Public hearing. If anyone contacts us requesting a public hearing
on or before November 16, 2020, we will hold a virtual public hearing.
See SUPPLEMENTARY INFORMATION for information on requesting and
registering for a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2002-0037, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/
(our preferred method). Follow the online instructions for submitting
comments.
     Email<EMAIL_ADDRESS>Include Docket ID No. EPA-
HQ-OAR-2002-0037 in the subject line of the message.
     Fax:<PHONE_NUMBER>. Attention Docket ID No. EPA-HQ-OAR-
2002-0037.
     Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Docket ID No. EPA-HQ-OAR-2002-0037, Mail Code 28221T, 1200
Pennsylvania Avenue NW, Washington, DC 20460.
     Hand Delivery or Courier (by scheduled appointment only):
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. Out of an abundance of caution
for members of the public and our staff, the EPA Docket Center and
Reading Room are closed to the public, with limited exceptions, to
reduce the risk of transmitting COVID-19. Our Docket Center staff will
continue to provide remote customer service via email, phone, and
webform. We encourage the public to submit comments via https://www.regulations.gov/ or email, as there may be a delay in processing
mail and faxes. For further information on EPA Docket Center services
and the current status, please visit us online at https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed
action, contact Ms. Jennifer Caparoso, Sector Policies and Programs
Division (E143-01), Office of Air Quality Planning and Standards, U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina
27711; telephone number:<PHONE_NUMBER>; fax number:<PHONE_NUMBER>;
and email address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:
    Participation in virtual public hearing. Please note that the EPA
is deviating from its typical approach because the President has
declared a national emergency. Due to the current Centers for Disease
Control and Prevention (CDC) recommendations, as well as state and
local orders for social distancing to limit the spread of COVID-19, the
EPA cannot hold in-person public meetings at this time.
    If requested, the virtual hearing will be held on November 24,
2020. The hearing will convene at 9:00 a.m. Eastern Time (ET) and will
conclude at 3:00 p.m. ET. The EPA may close a session 15 minutes after
the last pre-registered speaker has testified if there are not
additional speakers. The EPA will announce further details on the
virtual public hearing website at https://www.epa.gov/stationary-sources-air-pollution/polyvinyl-chloride-and-copolymers-production-national-emission-0.
    The EPA will begin pre-registering speakers for the hearing upon
publication of this document in the Federal Register. To register to
speak at the virtual hearing, please use the online registration form
available at: https://www.epa.gov/stationary-sources-air-pollution/polyvinyl-chloride-and-copolymers-production-national-emission-0 or
contact Ms. Virginia Hunt at<PHONE_NUMBER> or by email at
<EMAIL_ADDRESS>The last day to pre-register to speak at the
hearing will be November 23, 2020. Prior to the hearing, the EPA will
post a general agenda that will list pre-registered speakers in
approximate order at https://www.epa.gov/stationary-sources-air-pollution/polyvinyl-chloride-and-copolymers-production-national-emission-0.
    The EPA will make every effort to follow the schedule as closely as
possible on the day of the hearing; however, please plan for the
hearing to run either ahead of schedule or behind schedule.
    Each commenter will have 5 minutes to provide oral testimony. The
EPA encourages commenters to provide the EPA with a copy of their oral
testimony electronically by emailing it to<EMAIL_ADDRESS>
The EPA also recommends submitting the text of your oral testimony as
written comments to the rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations
but will

not respond to the presentations at that time. Written statements and
supporting information submitted during the comment period will be
considered with the same weight as oral testimony and supporting
information presented at the public hearing.
    Please note that any updates made to any aspect of the hearing will
be posted online at https://www.epa.gov/stationary-sources-air-pollution/polyvinyl-chloride-and-copolymers-production-national-emission-0. While the EPA expects the hearing to go forward as set
forth above, if requested, please monitor our website or contact Ms.
Virginia Hunt at<PHONE_NUMBER> or<EMAIL_ADDRESS>to determine if
there are any updates. The EPA does not intend to publish a document in
the Federal Register announcing updates.
    If you require the services of a translator or a special
accommodation such as audio description, please pre-register for the
hearing with Virginia Hunt and describe your needs by November 16,
2020. The EPA may not be able to arrange accommodations without advance
notice.
    Docket. The EPA has established a docket for this rulemaking under
Docket ID No. EPA-HQ-OAR-2002-0037. 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 electronically in
Regulations.gov.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2002-0037. 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 electronically any information that you consider
to be CBI or other information whose disclosure is restricted by
statue. 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.
    The EPA is temporarily suspending its Docket Center and Reading
Room for public visitors, with limited exceptions, to reduce the risk
of transmitting COVID-19. Our Docket Center staff will continue to
provide remote customer service via email, phone, and webform. We
encourage the public to submit comments via https://www.regulations.gov/ as there may be a delay in processing mail and
faxes. Hand deliveries or couriers will be received by scheduled
appointment only. For further information and updates on EPA Docket
Center services, please visit us online at https://www.epa.gov/dockets.
    The EPA continues to carefully and continuously monitor information
from the CDC, local area health departments, and our federal partners
so that we can respond rapidly as conditions change regarding COVID-19.
    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-2002-0037. Note that
written comments containing CBI and submitted by mail may be delayed
and no hand deliveries will be accepted.
    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:

CAA Clean Air Act
CBI Confidential Business Information
CDC Centers for Disease Control and Prevention
CEMS continuous emission monitoring systems
CFR Code of Federal Regulations
EPA Environmental Protection Agency
ET Eastern Time
GACT generally achievable control technology
HAP hazardous air pollutant(s)
HON Hazardous Organic NESHAP
ICR Information Collection Request
LDAR leak detection and repair
MACT maximum achievable control technology
NAICS North American Industry Classification System
NESHAP national emission standards for hazardous air pollutants
NRDC Natural Resources Defense Council
NTTAA National Technology Transfer and Advancement Act
OMB Office of Management and Budget
ppm parts per million
ppmvd parts per million by volume dry
ppmw parts per million by weight
PRA Paperwork Reduction Act

PRD pressure relief device
PVC polyvinyl chloride and copolymers
PVCPU PVC production process unit
RDL representative detection level
RFA Regulatory Flexibility Act
SSM startup, shutdown, and malfunction
TEQ toxic equivalency
THC total hydrocarbons
TOHAP total non-vinyl chloride organic HAP
tpy tons per year
UMRA Unfunded Mandates Reform Act
UPL upper prediction limit

    Organization of this document. The information in this preamble is
organized as follows:

I. General Information
    A. What is the source of authority for the reconsideration
action?
    B. Does this action apply to me?
    C. Where can I get a copy of this document and other related
information?
II. Background
III. Reconsideration Issues, Request for Public Comments, and Other
Proposed Changes
    A. Process Vents
    B. Process Wastewater
    C. Stripped Resin
    D. Storage Vessels
    E. Affected Source
    F. Equipment Leaks
    G. Closed Vent Systems
    H. Affirmative Defense
I. Other Technical Corrections and Clarifications
IV. Summary of Cost, Environmental, and Economic Impacts
V. 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. What is the source of authority for the reconsideration action?

    The statutory authority for this action is provided by sections 112
and 307(d)(7)(B) of the Clean Air Act (CAA) (42 U.S.C. 7412 and
7607(d)(7)(B)).

B. Does this action apply to me?

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

 Table 1--Industrial Source Categories Affected by This Proposed Action
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               NESHAP and source category                 NAICS \1\ code
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Polyvinyl Chloride and Copolymers Production............          325211
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\1\ North American Industry Classification System.

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

C. 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/polyvinyl-chloride-and-copolymers-production-national-emission-0. Following
publication in the Federal Register, the EPA will post the Federal
Register version of the proposal at this same website.
    A redline version of the regulatory language that incorporates the
proposed changes in this action and supporting technical documents are
available in the docket for this rulemaking.

II. Background

    On July 10, 2002, the EPA promulgated the NESHAP for new and
existing PVC production facilities located at major sources in 40 CFR
part 63, subpart J (67 FR 45886). In that rulemaking, the EPA regulated
vinyl chloride as a surrogate for all HAP emitted from PVC production
and determined that the existing Vinyl Chloride NESHAP (40 CFR part 61,
subpart F) reflected the application of maximum achievable control
technology (MACT), thereby satisfying CAA section 112(d), except for
equipment leaks at new sources. For equipment leaks, the EPA required
that new sources comply with 40 CFR part 63, subpart UU.
    In October 2003, Mossville Environmental Action Now and Sierra Club
argued in the United States Court of Appeals for the District of
Columbia Circuit (the court) that the EPA had failed to set emission
standards for all HAP emitted by PVC plants. See Mossville
Environmental Action Now v. EPA, 370 F.3d at 1232 (D.C. Cir. 2004). The
EPA argued that it set emission standards for vinyl chloride as a
surrogate for all HAP emitted from the source category because it was
the predominant HAP used and emitted at PVC plants; however, the court
ruled that the EPA did not adequately explain the basis for its
decision to use vinyl chloride as a surrogate for the HAP other than
vinyl chloride. The court ``vacated and remanded [the rule in its
entirety] to the Agency for it to reconsider or properly explain its
methodology for regulating [HAP] emitted in PVC production other than
vinyl chloride by use of a surrogate.'' Id. at 370 F.3d at 1243.
    On January 23, 2007 (72 FR 2930), the EPA promulgated the NESHAP
for new and existing PVC production area sources in 40 CFR part 63,
subpart DDDDDD, based on generally achievable control technology (GACT)
under CAA section 112(d)(5), and required area sources to meet the
requirements in the existing Vinyl Chloride NESHAP (40 CFR part 61,
subpart F).
    On April 17, 2012 (77 FR 22848), in response to the 2004 court
remand in Mossville Environmental Action Now, the EPA finalized the
NESHAP for PVC production at major sources under CAA sections 112(d)(2)
and (3). In the same rulemaking, the EPA revised the area source
standards under CAA section 112(d)(6). The April 17, 2012, final major
and area source rules (herein referred to as the ``2012 final major and
area source rules'') established emission limits and work practice
standards for total organic HAP, and also for three specific HAP: Vinyl
chloride, chlorinated dibenzodioxins and furans (dioxins and furans),
and hydrogen chloride (HCl).\1\ To determine the

emissions limits and work practice standards, the EPA gathered
information on PVC production through public comment, review of
previously collected information, current literature, data from the
National Emissions Inventory, meetings and voluntary information
submissions by industry and the industry trade association. Also, in
the form of an electronic survey and emission testing of HAP, the EPA
collected information from PVC production facilities, as well as co-
located ethylene dichloride and vinyl chloride facilities. All Agency
correspondence related to the data gathering activities is provided in
the docket for this rulemaking.
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    \1\ The EPA did not set emission limits or work practice
standards for HCl from PVC area sources. Under CAA sections
112(c)(6) and 112(k), HCl was not determined to be one of the top 30
urban air toxics that pose the greatest potential health threat in
urban areas; thus, regulation as an area source is not warranted.
For additional details, see https://www3.epa.gov/airtoxics/area/arearules.html.
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    In June 2012, the EPA received four petitions for reconsideration
on the 2012 final major and area source rules pursuant to CAA section
307(d)(7)(B) from the following petitioners: One petition from
environmental groups (i.e., Mossville Environmental Action Now,
Louisiana Environmental Action Network, Air Alliance Houston, and
Sierra Club); and three petitions from the regulated industry and their
representatives (i.e., PolyOne Corporation, Saint-Gobain Corporation
and CertainTeed Corporation, and Vinyl Institute, Inc.). Copies of the
petitions are provided in the docket for this rulemaking (see Docket
Item Nos. EPA-HQ-OAR-2002-0037-0544, EPA-HQ-OAR-2002-0037-0568, EPA-HQ-
OAR-2002-0037-0217, and EPA-HQ-OAR-2002-0037-0569). At the same time,
the above petitioners, along with OxyVinyls, LP, petitioned the court
for judicial review of the 2012 final major and area source rules. The
petitioners primarily requested the EPA reconsider the emission limits
for process vents, process wastewater, and stripped resin because they
argued that it was not feasible to comment on the new data on which the
EPA based the final emission limits. Petitioners also argued that they
were not afforded the opportunity to comment on the subcategorization
of process vents and stripped resin. Petitioners requested that the EPA
reconsider and/or make changes to several other portions of the 2012
final major and area source rules; including requests that the EPA: (1)
Set the emission limits using data that represents the entire industry;
(2) allow vapor balancing as a method to control emissions from storage
vessels; (3) allow leak detection and repair (LDAR) of pressure
vessels; (4) revise emission profile requirements; (5) remove the
requirement to install electronic indicators on each pressure relief
device (PRD) that would be able to identify and record the time and
duration of each pressure release; and (6) remove certain aspects of
the bypass monitoring requirements, and leak monitoring and inspection
requirements. In addition, one petitioner said the EPA's assumption
that emission levels vary to the full extent of the 99th percent upper
prediction limit (UPL) is wrong and unsupported by the record; and the
EPA's decision to set MACT floors at 3 times the representative
detection level (RDL) when 3 times the RDL is greater than the UPL is
unlawful.
    On September 28, 2012, the EPA sent letters to petitioners (see
Docket Item Nos. EPA-HQ-OAR-2002-0037-0563 through EPA-HQ-OAR-2002-
0037-0566) informing them that: (1) The EPA was granting
reconsideration on at least petitioners' claims of inadequate
opportunity to comment on the emission limits for process vents,
process wastewater, and stripped resin for major and area sources; (2)
the EPA intended to issue a Federal Register document initiating notice
and comment rulemaking on the issues for which the Agency granted
reconsideration; and (3) the EPA was continuing to review the other
issues in the petitions for reconsideration and intended to take final
action on all issues no later than the date on which the EPA takes
final action on the reconsidered issues.
    In 2014, Mexichem Specialty Resins, Inc., Vinyl Institute, Inc.,
Saint-Gobain Corporation and CertainTeed Corporation, and OxyVinyls, LP
(Industry petitioners) petitioned the court to remove their case from
abeyance.\2\ The court removed the industry petitioners' cases from
abeyance and, on May 29, 2015, the court rejected the Industry
petitioners' arguments and denied their petitions for review. Mexichem
Specialty Resins, Inc. v. EPA, 787 F.3d 544 (D.C. Cir. 2015). Based on
this court decision, we consider all of the Industry petitioners'
reconsideration requests related to the interaction between non-PVC and
PVC-combined process vent limits and their subcategorization, vent gas
absorbers, PRDs, and bypasses to be resolved, as those issues were
addressed by the court.
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    \2\ The petition for judicial review filed on behalf of Air
Alliance Houston, Louisiana Environmental Action Network, Mossville
Environmental Action Now, and Sierra Club, was severed from the
industry case and is in abeyance pending the EPA's action on
reconsideration.
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    Furthermore, on August 20, 2013, the court issued its decision in
National Association of Clean Water Agencies v. EPA, which involved
challenges to the EPA's MACT standards for Sewage Sludge Incineration,
issued under CAA section 129. See 734 F.3d 1115. In this decision, the
court remanded certain aspects of the rule for further explanation,
including the question of how the UPL represents the MACT floor for new
and existing units, as required by the CAA. The Sewage Sludge
Incineration rule was issued on the same day as the Boilers and
Commercial and Industrial Solid Waste Incineration rules, and used the
same general methodology for calculating the MACT floors. For this
reason, the EPA requested an opportunity to supplement the record in
pending challenges to the Boilers and Commercial and Industrial Solid
Waste Incineration rules, to provide the explanation of the Agency's
analysis of variability in setting the MACT floor standards that the
court believed was needed in the record for the Sewage Sludge
Incineration rule. The court granted the EPA's motion for a remand of
the record on May 15, 2014. Details of how the UPL is used to calculate
the average emissions limitation achieved over time by the best
performing source or sources is documented in the memorandum, Use of
the Upper Prediction Limit for Calculating MACT Floors, which is
available in the docket for this rulemaking. We also note that on July
29, 2016, the court determined our UPL approach is reasonable in U.S.
Sugar Corp v. EPA, 830 F.3d 579, 639. Based on these details, we
consider all of the petitioners' requests related to the EPA's
methodology used to set MACT floors to be resolved.
    We considered all other reconsideration petition requests and
consolidated and grouped the issues for which we are granting
reconsideration into distinct topics which are discussed in section III
of this preamble.

III. Reconsideration Issues, Request for Public Comments, and Other
Proposed Changes

    To address selected issues raised in the four petitions for
reconsideration and not resolved by the May 29, 2015, court decision
(787 F.3d 544) as described above, the EPA is proposing revisions to
the emission limits in the 2012 major source rule for process vents and
process wastewater. In addition, the EPA is proposing other amendments
to the 2012 final major and area source rules, including technical
corrections and clarifications related to the standards for stripped
resin, storage vessels (including the use of vapor balancing),
equipment leaks, and closed vent systems. The EPA is also proposing to
clarify text and correct typographical errors, grammatical errors, and
cross-

reference errors in both rules. In addition, the EPA is proposing to
remove the affirmative defense provisions. To ensure public
participation in its final decisions, the EPA is requesting public
comment on only these specific issues as described below. The EPA will
not respond to any comments addressing any other provisions of the 2012
final major and area source rules or any other rules or issues.

A. Process Vents

    Following the 2011 proposal (76 FR 29528), the EPA received
comments and additional emissions data about process vents, and we used
this information to revise the process vent MACT floors and impacts for
the 2012 final major source rule. Details regarding the post-proposal
data submittals are discussed in the memorandum, Updated Information
Collection and Additional Data Received for the Polyvinyl Chloride and
Copolymers (PVC) Production Source Category, which is available in the
docket for this rulemaking (see Docket Item No. EPA-HQ-OAR-2002-0037-
0197). In the 2012 final major and area source rules, we established
process vent emission limits for vinyl chloride, dioxins and furans,
and total hydrocarbons (THC) or total organic HAP. For the 2012 final
major source rule, we also established process vent emission limits for
HCl as a surrogate for all acid gas HAP and chlorine gas. For the 2012
final area source rule, the process vent emission limits are based on
the baseline level of control (i.e., the control level that area
sources were meeting for existing and new sources) and the testing and
monitoring requirements are the same as the 2012 final major source
rule. To ensure that batch process vent streams are tested at worst-
case conditions, in the 2012 final major and area source rules, we
required that each batch process vent stream be characterized under
worst-case conditions by developing an emission profile. Also, in the
2012 final major and area source rules, we clarified the definitions
for process vent, continuous process vent, and batch process vent and
added a definition for miscellaneous vent. Refer to the preamble of the
2012 final major and area source rules (see section III of the 2012
final preamble, 77 FR 22850) for additional details about the process
vent standards.
    Petitioners primarily argue that it was not feasible to comment on
the new data on which the EPA based the final process vent emission
limits and subcategories; and as previously mentioned in section II of
this preamble, on September 28, 2012, the EPA granted reconsideration
on the process vent emission limits. We request public comments on the
process vent emission limits and subcategories. However, as discussed
later in this section of the preamble, we are also proposing to make
changes to the process vent emission limits and subcategories;
therefore, we also request public comments on these changes. In
addition, a petitioner said the EPA did not provide opportunity to
comment on the new, broader requirements for emission profiles that we
added to the 2012 final major and area source rules. The petitioner
also said the EPA did not provide opportunity to comment on the changes
we made in the 2012 final major and area source rules to the
definitions of process vent, continuous process vent, and batch process
vent or the new definition for miscellaneous vent. The EPA is granting
reconsideration on these other issues. Although we are not making any
changes to the requirements in the 2012 final major and area source
rules for emission profiles or to the definitions of process vent,
continuous process vent, batch process vent, and miscellaneous vent, we
request public comments on these requirements and definitions for the
reasons set forth in the 2012 final rules (see sections III.D.1 and V.I
of the 2012 final preamble, 77 FR 22855 and 22890).
    In response to the petitioner's claims, the EPA issued a CAA
section 114 Information Collection Request (ICR) on May 15, 2014, to
PVC production companies to gather data to inform the reconsideration
and potential revision of the process vent emission limits in the 2012
final major and area source rules (see Docket Item Nos. EPA-OAR-2002-
0037-0600, EPA-OAR-2002-0037-0601, EPA-OAR-2002-0037-0602, EPA-OAR-
2002-0037-0603, EPA-OAR-2002-0037-0604, EPA-OAR-2002-0037-0605, EPA-
OAR-2002-0037-0622, and EPA-OAR-2002-0037-0623). The data collected are
discussed in the memorandum, Technical Analysis and Documentation to
Support EPA's Reconsideration of 40 CFR part 63 Subpart HHHHHHH
National Emission Standards for the Polyvinyl Chloride and Copolymers
(PVC) Production Source Category, which is available in the docket for
this rulemaking. After reviewing all of the additional process vent
data that we collected since the promulgation of the 2012 final major
and area source rules, we are proposing changes to those rules.
    First, we are proposing changes to the 2012 final major and area
source rules related to the two subcategories for process vents (i.e.,
the ``PVC-only process vent'' and ``PVC-combined process vent''
subcategories). Although we are not proposing to change our
justification for establishing these two subcategories for process
vents (see section III.B of the 2012 final preamble, 77 FR 22850), we
are proposing to rename the ``PVC-only process vent'' subcategory the
``PVC process vent'' subcategory and revise the definition at 40 CFR
63.12005 such that a ``PVC process vent'' means a process vent that
originates from a PVC production process unit (PVCPU) and is not
combined with one or more process vents originating from the production
of vinyl chloride monomer or ethylene dichloride prior to being
controlled or emitted to the atmosphere. We are also proposing to
revise the definition of ``PVC-combined process vent'' at 40 CFR
63.12005 such that a ``PVC-combined process vent'' means a process vent
that originates from a PVCPU and is combined with one or more process
vents originating from the production of vinyl chloride monomer or
ethylene dichloride prior to being controlled or emitted to the
atmosphere. In other words, instead of a vent which is combined with
one or more process vents originating from any other source category
(as is the case in the 2012 final major and area source rules), we are
narrowing the definition of a ``PVC-combined process vent'' to refer to
a vent that is combined with one or more process vents originating from
the production of vinyl chloride monomer or ethylene
dichloride.3 4 These proposed definition changes more
accurately reflect the additional process vent data that we collected
since the promulgation of the 2012 final major and area source rules,
given that owners and operators of some vinyl chloride monomer or
ethylene dichloride production units combine their vinyl chloride
monomer, ethylene dichloride, and PVC process vents into one stream
prior to control and these combined streams have higher chlorinated
loads and flow rates than a PVC process vent (as defined in this
proposal). These proposed definition changes will impact

the subcategory designations of two PVC facilities if finalized as
proposed. Both facilities currently are in the ``PVC-combined process
vent'' subcategory and with the proposed definition changes, the
facilities would be in the ``PVC process vent'' subcategory. The
impacts to the emission limits for each of the proposed subcategories
due to the proposed definition changes are discussed below.
---------------------------------------------------------------------------

    \3\ We are also including a sentence in each of these
definitions to clarify that vent streams from process components
associated with the stripped resin downstream of the resin stripper
(e.g., dryers, centrifuges, filters) are not considered a PVC
process vent or a PVC-combined process vent because these vent
streams are subject to the stripped resin standards (see section
III.C of this preamble).
    \4\ We note that although these proposed changes are being made
directly in the 2012 final major source rule, these proposed changes
also result in revisions to the 2012 final area source rule because
40 CFR 63.11144(b) references 40 CFR 63.12005.
---------------------------------------------------------------------------

    Second, in light of the court's decision in Mexichem Specialty
Resins, Inc. v. EPA, 787 F.3d 544 (D.C. Cir. 2015), we are clarifying
at 40 CFR 63.11925(a) that if an applicable process vent stream at a
PVCPU is comingled with a vent stream from one or more non-PVCPU
sources (e.g., a vent stream from a vinyl chloride monomer, ethylene
dichloride production, or other chemical manufacturing process unit
subject to the Hazardous Organic NESHAP (HON), 40 CFR part 63, subparts
G, F, and H), and the comingled streams are vented through a shared
control device, then each emission standard (and subsequent control
device monitoring, recordkeeping, reporting, and other requirements)
from both the PVC NESHAP and any other NESHAP to which the comingled
vent stream is subject applies. In Mexichem Specialty Resins, Inc. v.
EPA, the court ruled that if ``a PVC manufacturer chooses to discharge
combined emissions from PVC and non-PVC processes through a single
vent, that manufacturer must comply with limits applicable to both and,
where they differ, comply with the more stringent of the two.'' For
this reason, and to clarify what the rules are intended to regulate, we
are also proposing to revise 40 CFR 63.11140(c) by removing the last
sentence and 40 CFR 63.11865 by removing the phrase ``or to chemical
manufacturing process units, as defined in Sec.  63.101, that produce
vinyl chloride monomer or other raw materials used in the production of
polyvinyl chloride and copolymers'' and we are proposing at 40 CFR
63.12005 to remove the last sentence in the definition of PVCPU. We
note that although the proposed changes at 40 CFR 63.11925(a) and 40
CFR 63.12005 are being made directly in the 2012 final major source
rule, these proposed changes also result in revision to the 2012 final
area source rule because 40 CFR 63.11142(f)(8) references 40 CFR
63.11925 and 40 CFR 63.11144 references 40 CFR 63.12005.
    Third, given that we are proposing to revise the definitions of
``PVC process vent'' and ``PVC-combined process vent'' as discussed
above (and which are referenced in the area source rule), we are also
proposing to amend the emission limits for PVC-combined process vents
in the 2012 final area source rule by eliminating the PVC-combined
process vent limits in the area source rule and instead require ``PVC-
combined process vents'' at area sources to meet the major source
process vent emission limits for ``PVC-combined process vents.'' Based
on the additional process vent data that we collected since the
promulgation of the 2012 final major and area source rules, we
determined that any facility producing vinyl chloride monomer and/or
ethylene dichloride is a major source (as defined in CAA section
112(a)) subject to the HON. Therefore, taking into consideration our
proposed definition of ``PVC-combined process vent,'' we do not believe
that there is any scenario where a PVC production area source can
combine its process vents with one or more process vents originating
from the production of vinyl chloride monomer or ethylene dichloride
and that combined process vent be routed to a control device being used
to comply with only an area source NESHAP. We estimate that there would
be no impact on any facility for making this change (i.e., to eliminate
the emission limits for PVC-combined process vents in the 2012 final
area source rule and instead require ``PVC-combined process vents'' at
an area source meet the major source process vent emission limits). We
are proposing at 40 CFR 63.11141(f) that all affected area sources that
commenced construction or reconstruction on or before May 20, 2011,
must be in compliance with this change within 3 years after the date of
publication of the final rule in the Federal Register. We also are
proposing at 40 CFR 63.11141(f) that all affected area sources that
commenced construction or reconstruction after May 20, 2011, must be in
compliance with this change upon the date of publication of the final
rule in the Federal Register or initial startup, whichever is later. We
are not aware of any sources that have commenced construction or
reconstruction after May 20, 2011, which would be impacted by the
application of the changes.
    Fourth, we are proposing to revise the process vent emission limits
in the 2012 final major source rule. As part of the May 15, 2014, CAA
section 114 ICR, we asked for sampling and analysis of HAP including
vinyl chloride, HCl, dioxins/furans, and THC from process vents
operating at maximum mass loading of all HAP compounds under normal
operation at eight PVC production facilities. Those data were
incorporated with the previously submitted data used to support the
2012 final major source rule process vent emission limits. We then
recalculated the process vent emission limits for vinyl chloride, total
organic HAP, HCl, dioxins/furans, and THC accounting for the additional
data received in response to the May 15, 2014, CAA section 114 ICR and
also accounting for the change in subcategory for two PVC facilities
based on our proposed revisions to the process vent subcategory
definitions. To account for variability, we calculated the proposed
MACT floors for vinyl chloride, total organic HAP, HCl, and dioxins/
furans for existing and new sources using a 99-percent UPL calculation.
Given the large amount of data obtained, we calculated the proposed
MACT floors for THC for existing and new sources using a 99-percent
upper limit calculation. Tables 2 and 3 of this preamble compare the
2012 final major source rule PVC process vent emission limits and PVC-
combined process vent emission limits, respectively, to the process
vent emission limits that we are proposing in this action. Also, as
part of a beyond-the-floor analysis, we analyzed the cost and emissions
reductions for an existing facility to install a refrigerated condenser
prior to the existing thermal oxidizer and acid gas scrubber to meet
the proposed new source standards for process vents; and we determined
that the overall annual cost would be $7.2 million, and the annual
emissions reductions would be 105 tons of HAP per year (approximately
$68,000/ton cost effectiveness). Furthermore, the only beyond-the-floor
option we identified for new sources is a refrigerated condenser prior
to the thermal oxidizer and acid gas scrubber. However, similar to the
analysis for existing sources, installing a refrigerated condenser
prior to the thermal oxidizer and acid gas scrubber at a new source to
achieve beyond-the-MACT-floor level of control would also not be cost
effective (i.e., higher cost with potentially less HAP removal than
existing sources). We did not identify any other measures or control
technologies to further reduce emissions from process vents in the PVC
production industry. Based on this analysis, we are proposing that it
is not cost effective to go beyond-the-floor for process vents at
existing or new sources. Our emission limit calculations, beyond-the-
floor analysis, and the methodology we used to calculate costs and
emission reductions are discussed in the memorandum, Technical Analysis
and Documentation to Support EPA's Reconsideration of 40 CFR part

63 Subpart HHHHHHH National Emission Standards for the Polyvinyl
Chloride and Copolymers (PVC) Production Source Category, which is
available in the docket for this rulemaking.

   Table 2--Comparison of 2012 Final Major Source Emission Limits and Proposed Emission Limits for PVC Process
                                                      Vents
----------------------------------------------------------------------------------------------------------------
                                                  2012 Final major rule emission   Proposed emission limits for
                                                   limits for pvc process vents          pvc process vents
                    Pollutant                    ---------------------------------------------------------------
                                                     Existing                        Existing
                                                      sources       New sources       sources       New sources
----------------------------------------------------------------------------------------------------------------
Vinyl Chloride \1\..............................             6.0            0.56            0.85            0.85
Total Organic HAP \1\...........................              56             5.5              22             1.3
HCl \1\.........................................              78            0.17            0.64            0.17
Dioxins/Furans \2\..............................           0.038           0.038           0.035           0.035
THC \3\.........................................             9.7             7.0             5.1             2.2
----------------------------------------------------------------------------------------------------------------
\1\ Parts per million by volume dry (ppmvd) @3-percent (%) oxygen (O2).
\2\ Nanograms per dry standard cubic meters (ng/dscm) @3% O2 toxic equivalency (TEQ).
\3\ ppmvd as propane @3% O2.

  Table 3--Comparison of 2012 Final Major Source Emission Limits and Proposed Emission Limits for PVC-Combined
                                                  Process Vents
----------------------------------------------------------------------------------------------------------------
                                                  2012 final major rule emission   Proposed emission limits for
                                                     limits for PVC- combined       PVC-combined process vents
                                                           process vents         -------------------------------
                    Pollutant                    --------------------------------
                                                     Existing                        Existing       New sources
                                                      sources       New sources       sources
----------------------------------------------------------------------------------------------------------------
Vinyl Chloride \1\..............................             1.1            0.56            0.85            0.85
Total Organic HAP \1\...........................             9.8             5.5             9.7             5.9
HCl \1\.........................................             380             1.4             3.9             1.4
Dioxins/Furans \2\..............................           0.051           0.034            0.68           0.051
THC \3\.........................................             4.2             2.3             9.1             2.2
----------------------------------------------------------------------------------------------------------------
\1\ ppmvd @3% O2.
\2\ ng/dscm @3% O2 TEQ.
\3\ ppmvd as propane @3% O2.

    We are proposing the revised major source process vent emission
limits in new Tables 1b and 2b to 40 CFR part 63, subpart HHHHHHH; and
we are proposing that all affected major sources that commenced
construction or reconstruction on or before May 20, 2011, must be in
compliance with these changes within 3 years after the date of
publication of the final rule in the Federal Register. We also are
proposing that all affected major sources that commenced construction
or reconstruction after May 20, 2011, must be in compliance with these
changes upon the date of publication of the final rule in the Federal
Register or initial startup, whichever is later. We are not aware of
any major sources that have commenced construction or reconstruction
after May 20, 2011, which would be impacted by the application of the
changes. See proposed 40 CFR 63.11875(e). Also, at any time before
these compliance dates, we are proposing at 40 CFR 63.11880(d) that an
affected major source may choose to comply with the revised emission
limits in Tables 1b and 2b to 40 CFR part 63, subpart HHHHHHH, in lieu
of the emission limits in Tables 1 and 2 to 40 CFR part 63, subpart
HHHHHHH. Also, as previously mentioned in section II of this preamble,
on September 28, 2012, the EPA granted reconsideration on the emission
limits. We are not making any changes to the process vent emission
limits in the area source rule; however, we request public comments on
these emission limits.
    Finally, we are proposing to revise several paragraphs throughout
the 2012 final major and area source rules, (including process vent
related requirements in 40 CFR 63.11925 through 63.11950) to properly
reference the proposed Tables 1b and 2b to 40 CFR part 63, subpart
HHHHHHH. For example, for 40 CFR part 63, subpart DDDDDD, although 40
CFR 63.11925 is referenced in 40 CFR 63.11142(f)(8), we are proposing
to revise the introduction paragraph at 40 CFR 63.11142(f) to ensure
that whenever reference is made to Tables 1, 1b, 2, or 2b to 40 CFR
part 63, subpart HHHHHHH, we mean Table 1 or 2 to 40 CFR part 63,
subpart DDDDDD, for purposes of compliance with the 2012 area source
process vent standards. We are also proposing several other editorial
corrections and clarifications to the process vent requirements in 40
CFR 63.11925 through 63.11950. These proposed amendments are discussed
in section III.I of this preamble.
    The EPA is soliciting comment on all of the proposed changes
discussed in this section of the preamble (i.e., the revised
subcategories for process vents, the clarifications to 40 CFR
63.11140(c), 63.11865, 63.11925(a), and 63.12005 addressing comingled
vent streams, the elimination of the emission limits for PVC-combined
process vents in the 2012 final area source rule, the revised major
source process vent emission limits, the compliance dates, and whether
there are any sources that commenced construction after May 20, 2011).
Except for the proposed major source process vent emission limits, we
note (as previously mentioned) that all of the other proposed changes
discussed in this section of the preamble are also being proposed for
the 2012 area source rule at 40 CFR 63.11142(f)(8) through (13) and
63.11144 because 40 CFR 63.11925 through 63.11950 and 63.12005 are
referenced in those

requirements. If it is determined that there are sources that have
commenced construction or reconstruction after May 20, 2011, then we
will need to add additional requirements.

B. Process Wastewater

    The 2012 final major source rule contains vinyl chloride and total
non-vinyl chloride organic HAP (TOHAP) emission limits for process
wastewater. For the 2012 final major source rule, the vinyl chloride
emission limits were calculated based on one year of sampling data
provided post-proposal by the industry. The major source TOHAP emission
limits were based on information and data provided by industry in
response to the August 21, 2009, CAA section 114 ICR, corrections to
those data provided by the PVC industry during the public comment
period, and supplemental wastewater sampling data provided during the
public comment period by one PVC manufacturer. The August 21, 2009, CAA
section 114 ICR is documented in the memoranda, Information Collection
for the Polyvinyl Chloride and Copolymers (PVC) Production Source
Category and Updated Information Collection and Additional Data
Received for the Polyvinyl Chloride and Copolymers (PVC) Production
Source Category, which are available in the docket for this rulemaking
(see Docket Item Nos. EPA-HQ-OAR-2002-0037-0099 and EPA-HQ-OAR-2002-
0037-0197, respectively). Refer to the preamble of the 2012 final major
and area source rules (see section III of the 2012 final preamble, 77
FR 22850) for additional details about the emission limits for process
wastewater.\5\
---------------------------------------------------------------------------

    \5\ We note that subsequent to the April 17, 2012, rulemaking,
PVC industry stakeholders notified the EPA that the data used to set
the new and existing area source TOHAP process wastewater emission
limits were not based on data from the PVC Production source
category. The EPA agreed with the PVC industry stakeholders and on
February 4, 2015, the EPA issued a direct final rule (80 FR 5938,
February 4, 2015) withdrawing the TOHAP process wastewater emission
standards in 40 CFR part 63, subpart DDDDDD, for new and existing
PVC production area sources.
---------------------------------------------------------------------------

    Petitioners primarily argue that it was not feasible to comment on
the new data on which the EPA based the final process wastewater
emission limits; and as previously mentioned in section II of this
preamble, on September 28, 2012, the EPA granted reconsideration on
this issue. The petitioners argued that the EPA did not base the TOHAP
emission limits on emission levels actually achieved by the best
performing sources in the source category. One of the petitioners said
that the EPA did not provide rationale for why nine out of 18
facilities (for which it had data) represented the top performing
sources. Other petitioners argued that the data points do not reflect
actual samples of PVC facility process wastewater taken during actual
operations.
    In response to the petitioner's claims, the EPA issued a CAA
section 114 ICR on November 8, 2012, to PVC production companies to
gather data to inform the reconsideration and potential revision of the
process wastewater emission limits in the 2012 final major and area
source rules. Also, the EPA issued an additional CAA section 114 ICR on
April 1, 2014, to two companies that were not included in the November
8, 2012, CAA section 114 request. These two CAA section 114 ICRs are
available in the docket for this rulemaking (see Docket Item Nos. EPA-
OAR-2002-0037-0543, EPA-OAR-2002-0037-0592, EPA-OAR-2002-0037-0593, and
EPA-OAR-2002-0037-0594). The data collected are discussed in the
memorandum, Technical Analysis and Documentation to Support EPA's
Reconsideration of 40 CFR part 63 Subpart HHHHHHH National Emission
Standards for the Polyvinyl Chloride and Copolymers (PVC) Production
Source Category, which is available in the docket for this rulemaking.
Each owner or operator was required to take one grab sample from each
PVC process wastewater treatment stream for 30 consecutive days and
then analyze the samples for specified HAP using the prescribed EPA
test methods. If a facility had a batch PVC operation that did not
operate 30 consecutive days, then it was required to collect samples at
least once for each day while any batch wastewater treatment system was
operating such that at least 30 samples were analyzed. Data were also
collected on other wastewater streams (i.e., streams not stripped and
streams slated for on-site or off-site biological treatment units),
including average flow rate characteristics, origination, and
destination information. After reviewing all of the additional process
wastewater data that we collected since the promulgation of the 2012
final major and area source rules, we are proposing changes to the 2012
final major and area source rules.
    First, we are proposing to revise the process wastewater vinyl
chloride emission limit for major sources. Under the proposed
amendments, process wastewater streams at existing major sources would
be required to meet an emission limit of 0.73 parts per million by
weight (ppmw) for vinyl chloride (in lieu of the 6.8 ppmw vinyl
chloride process wastewater emission limit in the 2012 major source
rule for existing affected sources) before being exposed to the
atmosphere or discharged from the affected source (see proposed Table
1b to 40 CFR part 63, subpart HHHHHHH). Process wastewater streams at
new major sources would be required to meet an emission limit of 0.57
ppmw for vinyl chloride (in lieu of the 0.28 ppmw vinyl chloride
process wastewater emission limit in the 2012 major source rule for new
affected sources) before being exposed to the atmosphere or discharged
from the affected source (see proposed Table 2b to 40 CFR part 63,
subpart HHHHHHH). Given the large amount of data obtained, we
calculated these MACT floors (i.e., the proposed 0.73 ppmw and 0.57
ppmw vinyl chloride emission limits for existing and new major sources,
respectively) using a 99-percent upper limit calculation. Also, we
analyzed a beyond-the-floor option for controlling vinyl chloride from
process wastewater at existing sources, specifically evaluating the
cost and emissions reductions for an existing facility to meet the
level of control that we are proposing for new sources, based on
replacement of their existing wastewater steam stripper. We determined
that the overall annual cost (including installation and operation)
would be about $11 million, and the annual emissions reductions would
be 1.3 tons of HAP per year (approximately $8.6 million/ton cost
effectiveness). Furthermore, the only beyond-the-floor option we
identified for new sources is a larger or secondary steam stripper.
However, similar to the analysis for existing sources, installing a
larger or secondary steam stripper at a new source to achieve beyond-
the-MACT-floor level of control would also not be cost effective (i.e.,
higher cost with potentially less HAP removal than existing sources).
We did not identify any other measures or control technologies to
further reduce emissions from process wastewater in the PVC production
industry. Based on this analysis, we are proposing that it is not cost
effective to go beyond-the-floor for process wastewater at existing or
new sources. Our MACT floor emission limit calculations, beyond-the-
floor analysis, and the methodology we used to calculate costs and
emission reductions are discussed in the memorandum, Technical Analysis
and Documentation to Support EPA's Reconsideration of 40 CFR part 63
Subpart HHHHHHH National Emission Standards for the Polyvinyl Chloride
and Copolymers (PVC) Production Source Category, which is available in
the docket for this rulemaking. Also, as previously

mentioned in section II of this preamble, on September 28, 2012, the
EPA granted reconsideration on the emission limits. We are not making
any changes to the wastewater emission limits in the area source rule;
however, we request public comments on these emission limits.
    Second, we are proposing to remove the major source process
wastewater TOHAP emission limit and establish vinyl chloride as a
surrogate for TOHAP for major and area sources. As noted above,
petitioners argue that the EPA did not base the TOHAP emission limits
on emission levels actually achieved by the best performing sources in
the source category. One of the petitioners said that the EPA did not
set the MACT floor using data for the top performing sources. Another
petitioner argued that the data points do not reflect actual samples of
PVC facility process wastewater taken during actual operations. We are
proposing to eliminate the process wastewater TOHAP emission limit and
to be more fully responsive to the court's original request that the
EPA ``properly explain its methodology for regulating [HAP] emitted in
PVC production other than vinyl chloride by use of a surrogate.'' See
Mossville Environmental Action Now v. EPA, 370 F.3d at 1232 (D.C. Cir.
2004). In this proposal, we have redetermined and are further
explaining the basis for our conclusion that vinyl chloride is a
suitable surrogate for establishing process wastewater emission limits
for organic HAP. We note that the court (370 F.3d at 1242-43) held that
the EPA has authority to use a surrogate ``if it is reasonable to do
so[.]'' For the reasons discussed below, we have determined that vinyl
chloride is a reasonable surrogate for TOHAP emitted from process
wastewater at PVC production facilities.
    Steam stripping is an effective wastewater treatment technology
that has been used as the basis of wastewater emission control
requirements in many rules, including the 40 CFR part 63 MACT for
chemical process industries, such as the HON, Miscellaneous Organic
Chemical Manufacturing NESHAP, and Polymers and Resins NESHAP as well
as the 40 CFR part 61 Benzene Waste Operations NESHAP. The approach is
based on the idea that removal of pollutants from wastewater prior to
discharge into a facility's wastewater collection and treatment system
will limit air emissions resulting from volatilization of these
pollutants from downstream process drains and conveyances that are open
to the atmosphere, as well as from the downstream biological treatment
system, including biological treatment units that are agitated and
aerated to supply the microorganisms with O2. Conversely,
those pollutants that are not effectively removed by a steam stripper
will be even less likely to volatilize in collection and treatment and
will be controlled in the facility's biological treatment system.
    All PVC manufacturers have high concentrations of vinyl chloride in
their process wastewater and steam stripping is widely used by PVC
manufacturers to remove and recover vinyl chloride from process
wastewater streams. The best performers that the MACT floor is based on
are those strippers that have the lowest vinyl chloride concentrations
in the bottoms (outlet) stream exiting the steam stripper; that is, the
most effective strippers are those that result in the lowest
concentration of vinyl chloride in the bottoms stream.
    Based on the data we received in response to our CAA section 114
ICRs of PVC manufacturers, 33 non-vinyl chloride HAP are also present
in the bottoms of the stripped wastewater streams. While many of these
non-vinyl chloride HAP are removed using steam stripping, some are
removed to a lesser degree. The EPA thoroughly examined the
fundamentals of steam stripping wastewater (including calculating the
HAP fraction removed (Fr) values \6\ for a model steam stripper and the
fraction emitted (Fe) values \7\ for numerous HAP from wastewater)
during the original rulemaking of the HON (see Legacy Docket A-90-23).
Based on this information as well as the data we received in response
to our CAA section 114 ICRs, we determined that 25 of the 33 non-vinyl
chloride HAP in the stripped wastewater have lower concentrations than
the average vinyl chloride concentration and have Fr values of 0.99
which is the same Fr value for vinyl chloride.\8\ In other words, vinyl
chloride and most non-vinyl chloride HAP are effectively removed from
the wastewater stream using steam stripping. We, therefore, conclude
that vinyl chloride is a reasonable surrogate for these HAP. Although
the remaining eight non-vinyl chloride HAP have stripper bottoms
concentrations higher than vinyl chloride and have Fr values from 0.31
(methanol) to 0.99 (vinyl acetate),\9\ these HAP are not likely to be
emitted to the atmosphere because these HAP have low Fe values,
significantly less than that of vinyl chloride. The Fe values for these
compounds range from 0 (ethylene glycol) to 0.59 (vinyl acetate),
compared to vinyl chloride's Fe value of 0.97. As a result, these HAP
other than vinyl chloride that remain in the stripped wastewater are
more likely to remain in the wastewater collection system and will be
readily biodegraded in the biological treatment unit. Furthermore, we
observed that non-vinyl chloride HAP concentrations at the outlet of
the steam stripper are the result of varied resin recipe slates in use
throughout the industry, and, therefore, do not correlate with the
effectiveness of the steam stripper at removing vinyl chloride. For
example, resin grade recipes lower in hard-to-strip TOHAP could allow
for poorer stripper performance if TOHAP were being relied to determine
MACT. Therefore, the steam strippers that are the best performers can
be identified by their low vinyl chloride concentrations and not by the
non-vinyl chloride HAP concentrations in the stripper bottoms.
---------------------------------------------------------------------------

    \6\ The Fr is the mass fraction of a HAP that is stripped from
the wastewater. The Fr values for individual HAP in a model steam
stripper were estimated using Henry's Law Constants at 100 degrees
Celsius during the development of the HON. See 57 FR 62641, December
31, 1992; 59 FR 19443 and 4, April 22, 1994; and the memoranda,
Henry's Law Constants for the 83 HAP's Regulated in the Proposed HON
Wastewater Provisions; and Efficiency of Steam Stripper Trays to
Treat Wastewater Streams: Prediction of the Fraction Removed (Fr)
for Specific Compounds, which are available in the docket for this
rulemaking.
    \7\ The Fe is the mass fraction of a HAP that is emitted from
the wastewater collection and downstream biological treatment
system. The Fe values for individual HAP were calculated during the
development of the HON. See 57 FR 62641, December 31, 1992; 59 FR
19443 and 4, April 22, 1994; and the memorandum, Estimation of Air
Emissions from Model Wastewater Collection and Treatment Plants
Systems, which is available in the docket for this rulemaking.
    \8\ See the memorandum, Analysis of HAP in PVC Process
Wastewater, which is available in the docket for this rulemaking.
    \9\ Only three of 15 facilities reported data where vinyl
acetate concentrations in the stripper bottoms were higher than
vinyl chloride. One facility is no longer in operation and the other
two are vinyl chloride/vinyl acetate copolymer producers. Therefore,
the higher vinyl acetate fraction is likely the result of resin
recipe influence rather than stripper performance since vinyl
chloride and vinyl acetate have the same Fr value.
---------------------------------------------------------------------------

    In summary, vinyl chloride serves as an appropriate surrogate for
determining the MACT floor for process wastewater. First, vinyl
chloride is the predominant HAP and is present in all process
wastewater streams. Second, the best performing strippers are
identified by low vinyl chloride concentrations in the stripper bottoms
and are also the most effective strippers at removing non-vinyl
chloride HAP. The other non-vinyl chloride HAP present in the stripper
bottoms are a reflection of the resin recipe and not the effectiveness
of the stripper. The non-vinyl chloride HAP that are in the stripper
bottoms will not volatilize in collection systems

and be effectively treated in the biological treatment unit. The
regulatory objective of this rule is to control air emissions of HAP
from wastewater streams and not to control HAP that are in the
wastewater streams. Focusing on vinyl chloride rather than total
organic HAP for setting standards for PVC process wastewater not only
ensures identification of the best performing wastewater strippers for
the primary HAP emitted from the source category, but also ensures the
effective control of air emissions of non-vinyl chloride organic HAP
from wastewater.\10\ Additional details about our proposed surrogacy
are provided in the memorandum, Analysis of HAP in PVC Process
Wastewater, which is available in the docket for this rulemaking.
---------------------------------------------------------------------------

    \10\ See 57 FR 62641, December 31, 1992.
---------------------------------------------------------------------------

    We are proposing these changes (i.e., to revise the process
wastewater vinyl chloride emission limit and eliminate the process
wastewater TOHAP emission limit) in new Tables 1b and 2b to 40 CFR part
63, subpart HHHHHHH; and we are proposing that all affected major
sources that commenced construction or reconstruction on or before May
20, 2011, must be in compliance with these changes within 3 years after
the date of publication of the final rule in the Federal Register. We
also are proposing that all affected major sources that commenced
construction or reconstruction after May 20, 2011, must be in
compliance with these changes upon the date of publication of the final
rule in the Federal Register or initial startup, whichever is later.
See proposed 40 CFR 63.11875(e). We are not aware of any major sources
that have commenced construction or reconstruction after May 20, 2011,
which would be impacted by the application of the changes. Also, at any
time before these compliance dates, we are proposing at 40 CFR
63.11880(d) that an affected major source may choose to comply with the
revised emission limits in Tables 1b and 2b to 40 CFR part 63, subpart
HHHHHHH, in lieu of the emission limits in Tables 1 and 2 to 40 CFR
part 63, subpart HHHHHHH.
    Finally, we are proposing to revise several paragraphs throughout
the major source rule (including process wastewater related
requirements in 40 CFR 63.11965 through 63.11985) to properly reference
the proposed Tables 1b and 2b to 40 CFR part 63, subpart HHHHHHH, and
to address the elimination of the major source process wastewater TOHAP
emission limit; and we are proposing to clarify in 40 CFR 63.11965(e)
that only 40 CFR 63.105(b) and (c) apply to maintenance wastewater
containing HAP listed in Table 10 to 40 CFR part 63, subpart HHHHHHH.
We are also proposing to correct a typographical error in Table 9 to 40
CFR part 63, subpart HHHHHHH, to be consistent with the requirement at
40 CFR 63.11980(a)(4)(i). Specifically, we are clarifying in Table 9 to
40 CFR part 63, subpart HHHHHHH, that compliance with the wastewater
emission limit is based on the results from one grab or composite
sample.
    The EPA is soliciting comment on all of the proposed changes
discussed in this section of the preamble (i.e., the revised process
wastewater vinyl chloride emission limits, the elimination of the
process wastewater TOHAP emission limits, the compliance dates, whether
there are any sources that commenced construction after May 20, 2011,
the clarification to 40 CFR 63.11965(e), and the correction in Table 9
to 40 CFR part 63, subpart HHHHHHH). We note that the proposed
clarification in 40 CFR 63.11965(e) is also being proposed for the 2012
area source rule at 40 CFR 63.11142(f)(17) because 40 CFR 63.11965 is
referenced in those requirements; however, the proposed process
wastewater vinyl chloride emission limits do not affect the 2012 area
source rule at 40 CFR 63.11142(f)(17). Although 40 CFR 63.11965 through
63.11980 are referenced in 40 CFR 63.11142(f)(17), we are proposing to
revise the introduction paragraph at 40 CFR 63.11142(f) to ensure that
whenever reference is made to Tables 1, 1b, 2, or 2b to 40 CFR part 63,
subpart HHHHHHH, we mean Table 1 or 2 to 40 CFR part 63, subpart
DDDDDD, for purposes of compliance with the 2012 area source wastewater
standards. If it is determined that there are major sources that have
commenced construction or reconstruction after May 20, 2011, then we
will need to add additional requirements.

C. Stripped Resin

1. Subcategories and Emission Limits
    Petitioners maintain that it was not feasible to comment on the new
data on which the EPA based the final stripped resin emission limits
and subcategories; and as previously mentioned in section II of this
preamble, on September 28, 2012, the EPA granted reconsideration on the
emission limits. We are not making any changes to the stripped resin
emission limits and subcategories in the 2012 final major and area
source rules; however, we request public comments on these emission
limits and subcategories.
2. Alternative Emission Limit Format for Compliance With Stripped Resin
Standards
    The existing Vinyl Chloride NESHAP (40 CFR part 61, subpart F)
provides emissions standards for the sources following the stripper
``stated in two ways'' (40 FR 59541, December 24, 1975). One of these
two formats for emissions standards is in ppmw of the stripped resin at
the outlet of the stripper and is used in both 40 CFR part 61, subpart
F, and the 2012 final major and area source rules, as seen in 40 CFR
61.64(e)(1), Tables 1 and 2 to 40 CFR part 63, subpart DDDDDD, and
Tables 1 and 2 to 40 CFR part 63, subpart HHHHHHH. The second format is
a mass emissions to the atmosphere, which is given as gram (g) HAP per
kilogram (kg) of product resin on a dry basis from the stripper (also
given in pound per ton format) and is only currently available in 40
CFR 61.64(e)(2). The EPA originally offered these two ``ways'' of
presenting an equivalent emission limit to acknowledge that there were
two distinctively different techniques to control these sources--add-on
control devices or improved stripping, and that different measurement
and enforcement methods are applicable to each technique (40 FR
59541).\11\ At the time, we also acknowledged that stripping is the
primary control technology on which the standards are based, lending
credence for including the ppmw format resin standard in the 2012 final
major and area source rules. However, we realize that some sources may
find compliance flexibility in complying with a mass emissions limit
instead of a stripped resin content, especially if centrifuges, blend
tanks, and other process components downstream of the stripper are
closed to the atmosphere, controlled with closed vent systems, and
routed to a control device. Therefore, we have calculated mass
emissions-formatted standards that are equivalent to the resin content
standards of the 2012 final major and area source rules using the
conversion methods used in the original 40 CFR part 61, subpart F
standards (i.e.,

converting the ppmw standard to g/kg, or part per thousand by weight
for the equivalent mass emission rate), and we are proposing to include
these alternative emission limits in Tables 1 and 2 to 40 CFR part 63,
subpart DDDDDD, and Tables 1b and 2b to 40 CFR part 63, subpart
HHHHHHH. In doing so in the same manner as the original 40 CFR part 61,
subpart F standards, we are ensuring that the alternate emission limits
can be implemented and enforced, will be clear to sources, and most
importantly, will be equivalent to the level of control required by the
MACT standards. We are proposing at 40 CFR 63.11960(b)(2) that if the
affected source chooses to comply with the alternative mass emission
rates, then the process components associated with the stripped resin
downstream of the resin stripper (e.g., dryers, centrifuges, filters)
must be enclosed and routed through a closed vent system meeting the
requirements in 40 CFR 63.11925 through 63.11950 for the closed vent
system and control device. We are also proposing calculation procedures
at 40 CFR 63.11960(g) and (h) that you must use if you elect to
demonstrate initial or continuous compliance with the alternative mass
emissions rates. In addition, we are proposing to clarify the reporting
and recordkeeping at 40 CFR 63.11985(b)(7) and 40 CFR 63.11990(h)(3) to
reflect the proposed option of complying with the alternative mass
emissions rates. The monitoring requirements for sources using the
alternative emission limits would include the same stack testing
methods and procedures required for process vent performance testing
instead of resin sampling and concentration analyses. By proposing
these alternative emission limits, we are providing the same level of
compliance flexibility afforded by the Vinyl Chloride NESHAP. Tables 4
and 5 of this preamble present the proposed mass emission limits for
existing and new sources, respectively. The EPA requests comment on the
proposed alternative emission limits. We note that all of the proposed
changes discussed in this section of the preamble (i.e., the proposed
changes to 40 CFR 63.11960, 40 CFR 63.11985(b)(7), and 40 CFR
63.11990(h)(3)) are also being proposed for the 2012 area source rule
at 40 CFR 63.11142(f)(16), (18), and (19) because 40 CFR 63.11960, 40
CFR 63.11985, and 40 CFR 63.11990 are referenced in those requirements.
---------------------------------------------------------------------------

    \11\ The EPA noted that the two emission limits ``are equivalent
if it is assumed that all residual vinyl chloride in the resin
leaving a stripper is emitted into the atmosphere at the polyvinyl
chloride plant.'' While acknowledging that a small proportion of
vinyl chloride might be left in the resin when it leaves the plant,
the residual vinyl chloride monomer left in the resin after
stripping would be emitted into the atmosphere at some point, and,
therefore, the EPA determined that the residual vinyl chloride
monomer in resin limits serve as an emission limitation ``specified
in a form which is compatible with the only practical method for
determining compliance.''

                Table 4--Proposed Existing Source Stripped Resin Alternative Mass Emission Limits
----------------------------------------------------------------------------------------------------------------
                                                                    40 CFR part                     40 CFR part
                                                    40 CFR part     63, subpart     40 CFR part     63, subpart
                                                    63, subpart    HHHHHHH non-     63, subpart     DDDDDD Non-
                Resin subcategory                  HHHHHHH vinyl  vinyl chloride   DDDDDD vinyl   vinyl chloride
                                                     chloride       organic HAP      chloride       organic HAP
                                                  emission limit  emission limit  emission limit  emission limit
                                                      (g/kg)          (g/kg)          (g/kg)          (g/kg)
----------------------------------------------------------------------------------------------------------------
Bulk resin......................................          0.0071            0.17          0.0071            0.17
Dispersion resin................................             1.3            0.24             1.5            0.32
Suspension resin................................           0.037            0.67           0.036           0.036
Suspension blending resin.......................            0.14            0.50            0.14            0.50
Copolymer resin.................................            0.79             1.9            0.79             1.9
----------------------------------------------------------------------------------------------------------------

                  Table 5--Proposed New Source Stripped Resin Alternative Mass Emission Limits
----------------------------------------------------------------------------------------------------------------
                                                                    40 CFR part                     40 CFR part
                                                    40 CFR part     63, subpart     40 CFR part     63, subpart
                                                    63, subpart    HHHHHHH non-     63, subpart     DDDDDD non-
                Resin subcategory                  HHHHHHH vinyl  vinyl chloride   DDDDDD vinyl   vinyl chloride
                                                     chloride       organic HAP      chloride       organic HAP
                                                  emission limit  emission limit  emission limit  emission limit
                                                      (g/kg)          (g/kg)          (g/kg)          (g/kg)
----------------------------------------------------------------------------------------------------------------
Bulk resin......................................          0.0071            0.17          0.0071            0.17
Dispersion resin................................            0.48           0.066             1.5            0.32
Suspension resin................................          0.0073           0.015           0.036           0.036
Suspension blending resin.......................            0.14            0.50            0.14            0.50
Copolymer resin.................................            0.79             1.9            0.79             1.9
----------------------------------------------------------------------------------------------------------------

3. Clarification of Initial and Continuous Monitoring of Non-Vinyl
Chloride Organic HAP
    The EPA's intent for demonstrating compliance with the total non-
vinyl chloride organic HAP emission limits for stripped resin within 40
CFR 63.11960(b) (and as referenced in 40 CFR 63.11142(f)(16) for area
sources) is for facilities to develop and maintain a specific list of
non-vinyl chloride organic HAP that are expected to be present in each
grade of resin produced by the PVCPU. The current rule language in 40
CFR 63.11960(b) is potentially unclear on how this list of HAP for each
resin grade is updated and used to demonstrate compliance and how this
list of HAP for each resin grade relates to the list of HAP contained
within Table 10 to 40 CFR part 63, subpart HHHHHHH. For example, in 40
CFR 63.11960(b), we are proposing to replace ``continuously updated''
with ``kept current'' to clarify the requirement that the facility-
specific HAP list is updated after any change occurs that would impact
the list of HAP for the stripped resin, such as using a new additive or
changing a vendor.
    In addition, as discussed in the 2012 final major and area source
rules (77 FR 22868), the EPA's intent is for sources to initially and
continuously test for all the HAP listed in Table 10 to 40 CFR part 63,
subpart HHHHHHH, plus any additional HAP not listed in Table 10 to 40
CFR part 63, subpart HHHHHHH, but expected to be present in the resin
grade due to the owner or operator's process

knowledge. That is, the facility-specific HAP list comprises the 30 HAP
in Table 10 to 40 CFR part 63, subpart HHHHHHH, plus any additional HAP
beyond those 30 that are expected to be present based on the resin
grades produced. The EPA is proposing clarifying amendments to 40 CFR
63.11960(b) and 40 CFR 63.11960(e)(1)(i) through (iv) related to the
specific HAP list, and we request comment on this clarification.
Furthermore, we are proposing amendments to 40 CFR 63.11960(b)(2) that
provide these clarifications on the facility-specific HAP list for
sources opting to comply with the proposed alternative mass emission
limits that are discussed in section III.C.2 of this preamble. Finally,
we are also proposing to restructure 40 CFR 63.11960(c) to improve
readability. We are proposing to remove duplicative language from 40
CFR 63.11960(c)(1)(iii) and (iv) and revise 40 CFR 63.11960(c)(2)(i)
and (ii) to clarify the calculation requirements for vinyl chloride and
non-vinyl chloride organic HAP.
    We note that these amendments are also being proposed for the 2012
area source rule at 40 CFR 63.11142(f)(16) because 40 CFR 63.11960 is
referenced in those requirements.

D. Storage Vessels

    We are proposing technical corrections and clarifications related
to the standards for pressure vessels, the use of vapor balancing, and
the standards for fixed roof and floating roof storage vessels. See
sections III.D.1, 2, and 3 of this preamble, respectively for a
detailed discussion of these proposed changes.
1. Pressure Vessels
    A petitioner requested that the EPA reconsider the requirements of
40 CFR 63.11910(c) and allow LDAR of all pressure vessel leaks,
including from closure devices. The petitioner stated that the rule
should apply LDAR as a work practice standard under CAA section 112(h)
for leaks from openings on pressure vessels that are equipped with
closure devices since it is ``not feasible to prescribe or enforce an
emission standard.'' The petitioner stated that the best performing
facilities use LDAR to manage leaks from pressure vessels and contended
that an allowance to make a repair once a leak is found is a common
approach for managing leaks from pressure vessels and is the only
achievable approach. The petitioner also stated it interprets the 2012
final major and area source rules to be that leaks from closure devices
are violations (according to 40 CFR 63.11910(c)(4)), while other
pressure vessel leaks are not violations and are subject to leak repair
provisions (according to 40 CFR 63.11910(c)(3)). The petitioner
requested that the EPA allow for repair of leaks from closure devices
greater than 500 parts per million (ppm) as a method of compliance.
    In the 2012 final major and area source rules, pressure vessels in
HAP service are required to operate as ``a closed system that does not
vent to the atmosphere'' and each opening must be equipped with a
closure device to prevent discharges to the atmosphere (40 CFR
63.11910(c)). In addition, in the 2012 final major and area source
rules, all potential leak interfaces on the vessel (including closure
devices) must be monitored annually for leaks. The intent of the 2012
final major and area source rules was to require that pressure vessels
operate with no detectable emissions (i.e., less than 500 ppm as
determined using EPA Method 21 of 40 CFR part 60, appendix A-7), and
that each opening, including all potential leak interfaces, on pressure
vessels be monitored regularly to ensure that the pressure vessels are
operating with no detectable emissions. While the 2012 final major and
area source rules do require potential leak interfaces to be monitored
annually for leaks using the procedures specified in the equipment leak
requirements at 40 CFR 63.11915, we recognize that the 2012 final major
and area source rules do not specify how 40 CFR 63.11915 would
specifically apply to pressure vessels and, thus, the petitioner
interpreted the rule to have two sets of leak requirements (one for
closure devices and another for all other pressure vessel leaks).
    The EPA is granting reconsideration of the pressure vessel
standards of 40 CFR 63.11910(c) but does not agree with the
petitioner's recommendations regarding LDAR. Specifically, the EPA is
not allowing for repair of leaks greater than 500 ppm as a method of
compliance. We are proposing to maintain the pressure vessel leak
requirements of the 2012 rules, with edits for clarity; pressure
vessels must operate with no detectable emissions and any release
greater than 500 ppm above background is a violation. This requirement
applies equally to closure device leaks and leaks from all other leak
interfaces on the pressure vessel. To confirm there are no detectable
emissions, we are proposing to specify (in lieu of generally pointing
to the LDAR requirements in 40 CFR 63.11915) that the affected source
must conduct annual monitoring of each potential leak interface and
each point on the pressure vessel through which HAP could potentially
be emitted, using the procedures specified in 40 CFR 63.1023(b) and
(c). This approach to regulating pressure vessel leaks is similar to
the Off-Site Waste and Recovery Operations NESHAP (40 CFR part 63,
subpart DD), which stipulates that tank openings must be equipped with
closure devices that are designed to operate with no detectable
emissions (see 40 CFR 63.685(h)(2)). We also propose to streamline and
combine the requirements at 40 CFR 63.11910(c)(3) and (4) for clarity.
Under the proposed language, 40 CFR 63.11910(c)(3) includes the
requirement to perform annual monitoring and states a leak greater than
500 ppm is a violation. We are proposing to remove certain language
specific to pressure vessel closure devices (which was previously at 40
CFR 63.11910(c)(4)), because closure device leaks would be captured by
the proposed language at 40 CFR 63.11910(c)(3) (i.e., monitor each
potential leak interface and each point on the pressure vessel through
which HAP could potentially be emitted). We are also proposing to
revise the language at 40 CFR 63.11890(d)(5)(iv) to apply more
generally to pressure vessel leaks instead of just closure devices;
this edit directly aligns with the proposed language at 40 CFR
63.11910(c)(3). In addition, we are proposing a definition of ``closure
device'' at 40 CFR 63.12005 to mean a cover, cap, hatch, lid, plug,
seal, valve, or other type of fitting that, when the device is secured
in the closed position, prevents or reduces air emissions to the
atmosphere by blocking an opening in a fixed roof storage vessel or
pressure vessel.
    As part of the leak monitoring revisions, we are proposing to
revise 40 CFR 63.11990(b)(4) to clarify that the pressure vessel leak
records must include the information already required to be reported in
the pressure vessel closure device deviation report pursuant to 40 CFR
63.11985(b)(10)(i) through (v) (e.g., we are proposing to keep records
of the quantity of vinyl chloride and total HAP released from the
closure device).
    The EPA is also proposing to clarify the requirements for filling,
emptying, and purging of pressure vessels at 40 CFR 63.11910(c)(1). The
clarifications are based on actual operations of PVC production
facilities and focus on the underlying pressure vessel standard.
Importantly, we are emphasizing that the underlying standard is that
each pressure vessel must be designed and operated as a closed system
without emissions to the atmosphere. The

language at 40 CFR 63.11910(c)(1) stating that the vent stream during
filling, emptying, and purging must meet the requirements of 40 CFR
63.11925(a) and (b) may appear to contradict the underlying standard
that pressure vessels must be designed and operated as a closed system
without emissions to the atmosphere.
    To better explain our intent in clarifying the proposed language at
40 CFR 63.11910(c)(1), one must consider where pressure vessels are
used at PVC production facilities, which is primarily for vinyl
chloride storage (the monomer that is used as a reactant in the
polymerization reaction to produce PVC). During filling operations,
pressure vessels are designed to operate as closed systems, so there
are no emissions from these sources during these periods. Once filled,
pressure vessels storing vinyl chloride are emptied by routing the
stored vinyl chloride to the process to be used in the polymerization
reaction. Once routed to the process, process vents may be created that
are subject to the process vent standards of 40 CFR 63.11925(a) and (b)
which include closed vent system requirements. In the case of vent
streams that contain any unreacted vinyl chloride, these streams are
typically routed to a recovery system and vinyl chloride is recovered
(to the extent practical) and sent back to the pressure vessel (which
still operates as a closed system without emissions to the atmosphere).
The remaining (noncondensable) vent stream containing small amounts of
unrecovered vinyl chloride (and possibly other compounds) then must be
controlled in order to comply with the process vent emission limits.
This was the intent of the language in the 2012 final major and area
source rules. Similarly, for purging operations, vinyl chloride is
typically sent to a recovery system and the recovered vinyl chloride is
then sent to a different pressure vessel also storing vinyl chloride
(which operates as a closed system without emissions to the
atmosphere). The remaining stream from the recovery system and the
pressure vessel being purged contains small amounts of unrecovered
vinyl chloride (and possibly other compounds) and must be controlled in
order to comply with the process vent emission limits. Thus, excluding
those emissions during filling, purging, and emptying that ultimately
end up as process vents that are routed to a closed vent system and
control device, there would still be no emissions to the atmosphere
directly from pressure vessels. We are proposing to clarify at 40 CFR
63.11910(c)(1) that for vent streams sent to the process from pressure
vessels, or purged from pressure vessels, facilities must prepare a
design evaluation to demonstrate certain conditions are met and meet
the requirements of 40 CFR 63.11925(a) and (b) including the closed
vent system requirements. We also note that we are proposing that
facilities may elect to comply with vapor balancing requirements during
filling operations. Vapor balancing does not result in emissions to the
atmosphere from pressure vessels and is a common equivalent control
option for PVC production facilities during filling operations (vapor
balancing requirements are discussed in greater detail in section
III.D.2 of this preamble).
    The EPA is soliciting comment on all of the proposed changes
discussed in this section of the preamble (i.e., the proposed changes
to the pressure vessel requirements in 40 CFR 63.11910(c), 40 CFR
63.11985(b)(10), and 40 CFR 63.11990(b)(4)). We note that all of these
proposed changes are also being proposed for the 2012 area source rule
at 40 CFR 63.11142(f)(5), (18), and (19) because 40 CFR 63.11910, 40
CFR 63.11985, and 40 CFR 63.11990 are referenced in those requirements.
2. Vapor Balancing
    A petitioner asserted that in the 2012 final major and area source
rules, the EPA did not specifically allow vapor balancing as a method
to control emissions from storage vessels. The petitioner stated that
vapor balancing is widely used in the PVC industry, indicated that 11
PVC production facilities use vapor balancing, and claimed it is
virtually impossible to unload a vinyl chloride railcar and not have
any HAP emissions without using vapor balancing. The petitioner also
noted that vapor balancing is allowed by the EPA in other MACT rules.
    The EPA agrees with the petitioner and is granting reconsideration
on allowing vapor balancing as a method to control emissions from
storage vessels. The 2012 final major and area source rules do not list
vapor balancing as a compliance option, but in responding to comments
in the 2012 final rules (refer to National Emission Standards for
Hazardous Air Pollutants for Polyvinyl Chloride and Copolymers
Production: Summary of Public Comments and Responses, Docket Item No.
EPA-HQ-OAR-2002-0037-0185), we stated that a PVC production facility
may request the EPA's approval to use vapor balancing as an alternative
means of emission limitation under 40 CFR 63.6(g) of the General
Provisions. The EPA acknowledges that vapor balancing is a proven
method to control emissions from storage vessel filling operations and
is already allowed by several MACT standards including the HON (40 CFR
part 63, subpart G). Therefore, the EPA is proposing vapor balancing
requirements at 40 CFR 63.11910(e) to allow vapor balancing as an
equivalent option to no emissions from pressure vessels during filling
operations (see proposed 40 CFR 63.11910(c)) and as an optional
equivalent control method for fixed roof storage vessels complying with
the 95-percent control standard for HAP emissions in Table 3 to 40 CFR
part 63, subpart HHHHHHH, during filling operations \12\ (see proposed
40 CFR 63.11910(d)). The proposed vapor balancing requirements at 40
CFR 63.11910(e) are similar to the HON requirements and include
operating, monitoring, and certification requirements and related
recordkeeping requirements.
---------------------------------------------------------------------------

    \12\ We note that facilities that use vapor balancing for
filling operations for fixed roof storage vessels that are required
to route emissions to a closed vent system and control device to
comply with the 95-percent control standard for HAP emissions must
comply with this standard at all times. In other words, while vapor
balancing fixed roof storage vessels during filling operations would
control working loss emissions to at least the 95-percent control
standard, owners or operators still have an obligation to control
other emissions from these fixed roof storage vessels to 95-percent
control, such as breathing losses and working losses that are not
vapor balanced.
---------------------------------------------------------------------------

    We are also proposing operating requirements for the vapor
balancing system. We are proposing that vapor balancing systems be
designed and operated to route vapors displaced from loading of the
storage vessel to the transport vehicle (i.e., railcar, tank truck,
barge) from which the storage vessel is being loaded. For vapor
balancing of pressure vessels, we are also proposing the transport
vehicle may then be depressurized by sending the vapors to the process.
We also propose that fluid transfer from a transport vehicle to a
storage vessel must be performed only when the transport vehicle's
vapor collection system is connected to the storage vessel vapor
balancing system. We are proposing a definition of vapor balancing
system at 40 CFR 63.12005 to mean a piping system that collects HAP
vapors displaced from transport vehicles (i.e., railcar, tank truck,
barge) during storage vessel loading and routes the collected vapors to
the storage vessel from which the HAP being loaded originated or to
another storage vessel connected to a common header; or a piping system
that collects HAP vapors

displaced from the loading of a storage vessel and routes the collected
vapors to the transport vehicle from which the storage vessel is
filled.
    In addition, we are proposing monitoring requirements for equipment
on the vapor balancing system. We are proposing that each PRD on a
storage vessel, transport vehicle, and vapor return line must remain
closed while the storage vessel is being filled and each PRD must be in
compliance with the rule's existing PRD monitoring requirements at 40
CFR 63.11915(c) (see section III.F of this preamble for details on
clarifications we are proposing for the rule's existing PRD monitoring
requirements). PVC production facilities commonly use vapor balancing
to unload vinyl chloride into pressure vessels, and as such, we are
also proposing the vapor balancing system must operate with no
detectable emissions, which is consistent with the proposed pressure
vessel requirements at 40 CFR 63.11910(c)(3) (see section III.D.1 of
this preamble). To confirm there are no detectable emissions, we are
proposing that the affected source must conduct annual monitoring of
each potential leak interface and each point on the vapor balancing
system through which HAP could potentially be emitted, using the
procedures specified in 40 CFR 63.1023(b) and (c).
    We are also proposing certification and control requirements for
transport vehicles. Prior to unloading into a storage vessel, we are
proposing that vapor balancing systems be designed and operated to
route vapors displaced from filling of the storage vessel to the
transport vehicle (i.e., railcar, tank truck, barge) from which the
storage vessel is being filled. We are proposing that tank trucks and
railcars must have a current certification from the U.S. Department of
Transportation and barges must have current certification of vapor-
tightness. To ensure the HAP that is vapor balanced from the PVC
storage vessel to the transport vehicle is not simply released to the
air, we are also proposing control and certification requirements for
reloading and cleaning of the transport vehicle (see 40 CFR
63.11910(e)(6) and (7)).
    Finally, we are proposing recordkeeping requirements at 40 CFR
63.11990(b)(7) if the affected source chooses to use this vapor
balancing option.
    The EPA is soliciting comment on all of the proposed changes
discussed in this section of the preamble (i.e., the proposed vapor
balancing requirements in 40 CFR 63.11910(e) and 40 CFR
63.11990(b)(7)). We note that these proposed vapor balancing
requirements are also being proposed for the 2012 area source rule at
40 CFR 63.11142(f)(5) and (19) because 40 CFR 63.11910 and 40 CFR
63.11990 are referenced in those requirements.
3. Fixed Roof and Floating Roof Storage Vessels
    We are clarifying requirements for fixed roof storage vessels using
closed vent systems and control devices that are being used to meet the
95-percent control standard for HAP emissions. To improve readability,
we are proposing to move the requirements for fixed roof storage
vessels using a closed vent system and control device to a separate
paragraph at 40 CFR 63.11910(d) and clarify the corresponding
requirements in Table 3 to 40 CFR part 63, subpart HHHHHHH. The 2012
final major and area source rules included the closed vent system and
control device requirements as part of the fixed roof storage vessel
requirements in 40 CFR 63.11910(a); however, our proposal to separate
the closed vent system and control device requirements from the fixed
roof storage vessel requirements provides clarity on what specific
requirements apply when a storage vessel is using a closed vent system
and control device versus the specific requirements that apply to a
fixed roof storage vessel. In addition, instead of complying with the
control device requirements for process vents, we are proposing that
for each fixed roof storage vessel that vents to a closed vent system
and control device, the affected source must develop a control device
operating plan and operate the control device according to the plan.
The proposed operating plan requirements are based on the requirements
in 40 CFR part 60, subpart Kb (40 CFR 60.113b(c)), because 40 CFR part
60, subpart Kb, formed the basis of the underlying standard for fixed
roof storage vessels that are routed to a closed vent system and
control device. However, we are also proposing the option to allow the
affected source to continue to comply with the control device
requirements for process vents provided that the storage vessel is
vented to a closed vent system and control device that is also used to
comply with the process vent emission limits.
    As an alternative for fixed roof storage vessels using a closed
vent system and control device to comply with the 95-percent control
standard for HAP emissions in Table 3 to 40 CFR part 63, subpart
HHHHHHH, we are proposing at 40 CFR 63.11910(d)(4) that fixed roof
storage vessel emissions may be routed back to the process instead of a
control device. The proposed requirements at 40 CFR 63.11910(d)(4)
include preparing a design evaluation to demonstrate certain conditions
are met. PVC production facilities also use vapor balancing systems,
and as discussed previously (see section III.D.2 of this preamble), we
are proposing this as a compliance method.
    Finally, to improve readability, we are proposing other
miscellaneous revisions to the fixed roof storage vessel requirements
at 40 CFR 63.11910(a) and the floating roof storage vessel requirements
at 40 CFR 63.11910(b). These proposed edits serve to clarify the
requirements and create consistency in the language, without changing
the underlying standards.
    The EPA is soliciting comment on all of the proposed changes
discussed in this section of the preamble (i.e., clarifications to the
fixed roof and floating roof storage vessel requirements). We note that
these proposed requirements are also being proposed for the 2012 area
source rule at 40 CFR 63.11142(f)(5) because 40 CFR 63.11910 is
referenced in those requirements.

E. Affected Source

    Petitioners maintain that it was not feasible to comment on the
revised definitions of the affected source at 40 CFR 63.11140(b) and 40
CFR 63.11870(b). The EPA is granting reconsideration on this issue.
Although we are not making any changes to the definitions of the
affected source in the 2012 final major and area source rules, we
request public comments on these definitions for the reasons set forth
in the 2012 final rules (see section III.A of the 2012 final preamble,
77 FR 22850).

F. Equipment Leaks

    Following the promulgation of the 2012 final major and area source
rules, the Vinyl Institute requested several clarifications on the
equipment leak provisions in 40 CFR 63.11915 in a letter \13\ dated
April 5, 2013. The Vinyl Institute said the requirements in the 2012
final major and area source rules at 40 CFR 63.11915(a) are
inconsistent with the EPA's conclusions discussed in the preamble to
the 2012 final rules (77 FR 22848) because the rule text only
references some of the requirements in 40 CFR part 63, subpart UU,
despite the fact that the preamble to the 2012 final

rules says that MACT (for equipment leaks at existing and new major
sources) as well as GACT (for equipment leaks at existing and new area
sources) is compliance with 40 CFR part 63, subpart UU, for all
equipment in HAP service as defined in 40 CFR 63.12005. Specifically,
the Vinyl Institute said that in referencing provisions of 40 CFR part
63, subpart UU, at 40 CFR 63.11915(a), the EPA excluded 40 CFR part 63,
subpart UU, requirements for applicability (40 CFR 63.1019), and
certain equipment, including: Pumps in light liquid service (40 CFR
63.1026), agitators in gas and vapor service and in light liquid
service (40 CFR 63.1028), and open-ended valves or lines (40 CFR
63.1033). Additionally, the Vinyl Institute said the compliance options
at 40 CFR 63.11915(b) are confusing and sometimes circular in
relationship to the requirements in 40 CFR part 63, subpart UU. In
particular, the Vinyl Institute said the compliance options at 40 CFR
63.11915(b) allowing use of either double (dual) mechanical seals or
sealless pumps to comply with 40 CFR part 63, subpart UU, are redundant
to compliance options already allowed in 40 CFR 63.1026; therefore, the
Vinyl Institute requested that the EPA remove this redundancy from 40
CFR 63.11915(b).
---------------------------------------------------------------------------

    \13\ Refer to the letter titled Clarification on Certain
Provisions in the National Emission Standards for Hazardous Air
Pollutants for Polyvinyl Chloride and Copolymer Production (``PVC
MACT''), from the Vinyl Institute to Andrea Siefers, U.S. EPA, dated
April 5, 2013, available in the docket for this rulemaking (see
Docket Item No. EPA-HQ-OAR-2002-0037-0560).
---------------------------------------------------------------------------

    The EPA agrees with the Vinyl Institute that the requirements in
the 2012 final major and area source rules at 40 CFR 63.11915(a) do not
properly reflect the EPA's MACT and GACT conclusions discussed in the
preamble to the 2012 final rules (77 FR 22848) regarding compliance
with 40 CFR part 63, subpart UU, for all equipment in HAP service as
defined in 40 CFR 63.12005. Therefore, for consistency with the EPA's
MACT and GACT conclusions discussed in the preamble to the 2012 final
major and area source rules (77 FR 22848), we are proposing to revise
40 CFR 63.11915(a) to include the requirements from 40 CFR part 63,
subpart UU, that are inadvertently missing from the 2012 final rules,
including: Applicability requirements (40 CFR 63.1019(a), and (c)
through (f)), requirements for pumps in light liquid service (40 CFR
63.1026), requirements for agitators in gas and vapor service and in
light liquid service (40 CFR 63.1028), and requirements for open-ended
valves or lines (40 CFR 63.1033).
    Also, we are proposing to remove all of the requirements in 40 CFR
63.11915(b) because we have determined that these requirements were
inadvertently published in the 2012 final major and area source rules
in error. We agree with the Vinyl Institute that the requirements in 40
CFR 63.11915(b) are confusing, and sometimes redundant or circular, in
relationship to the requirements in 40 CFR part 63, subpart UU. In
fact, the preamble to the 2012 final major and area source rules (77 FR
22848) makes it clear that the ``proposed requirement (at 40 CFR
63.11915(b)) that reciprocating pumps, reciprocating and rotating
compressors and agitators be equipped with double seals, or equivalent,
was in error. In the final rules, we have adopted the MACT floor level
of control for equipment leaks for all components (which is compliance
with 40 CFR part 63, subpart UU), which gives affected sources the
option of installing double seals, or equivalent, or complying with the
LDAR requirements of the equipment leak standards.''
    In addition, in a letter \14\ dated May 27, 2020, the Vinyl
Institute requested that the EPA clarify whether the 2012 final major
and area source rules require a release indicator to be installed
directly on each PRD. More specifically, the Vinyl Institute requested
that the EPA revise 40 CFR 63.11915(c)(1)(i) to allow the installation
of a release indicator in series with the PRD or in combination with
other sensors and monitoring systems in series with the PRD (in lieu of
requiring a release indicator be installed directly on each PRD). The
Vinyl Institute argued that it is not necessary for the release
indicator to be installed ``directly'' on the PRD in order to determine
whether an emission release has occurred. The Vinyl Institute said
facilities use a variety of sensor combinations and/or monitoring
systems (that are not always installed ``directly'' on the PRD, but
rather in series with the PRD) in order to determine whether an
emission release from a PRD has occurred.
---------------------------------------------------------------------------

    \14\ Refer to the letter titled RE: Description of Pressure
Relief Device Monitoring Practices for PVC Facilities, from the
Vinyl Institute to Jennifer Caparoso, U.S. EPA, dated May 27, 2020,
available in the docket for this rulemaking.
---------------------------------------------------------------------------

    It was not our intent to require only direct installation of a
release indicator on the PRD. Therefore, we are proposing to revise 40
CFR 63.11915(c) to clarify the PRD requirements that are beyond those
required in 40 CFR part 63, subpart UU; and to clarify that a release
indicator may either be installed on each PRD or installed on the
associated process or piping system in such a way that it will indicate
when an emission release has occurred. We are proposing that the
release indicator device or system can include, but is not limited to,
a rupture disk indicator, magnetic sensor, motion detector on the
pressure relief valve stem, flow monitor, or pressure monitor. We are
also clarifying in 40 CFR 63.11915(c)(1)(i) that the vinyl chloride
monitoring system required in 40 CFR 63.11956 is not considered a
release indicator for purposes of complying with 40 CFR
63.11915(c)(1)(i).
    Also, although 40 CFR part 63, subpart UU, references the closed
vent system requirements in 40 CFR part 63, subpart SS, we are
proposing at 40 CFR 63.11915(d) that if the affected source routes
emissions from equipment in HAP service through a closed vent system to
a control device, or back into the process or a fuel gas system, then
the affected source must comply with 40 CFR 63.11930 in lieu of the
closed vent system requirements specified in 40 CFR 63.983 of subpart
SS, and the recordkeeping and reporting requirements associated with 40
CFR 63.983 of subpart SS do not apply. Alternatively, we are proposing
an option that allows the affected source to comply with the control
device and closed vent system requirements for process vents, provided
that the emissions from equipment are vented to the same closed vent
system and control device that is also used to comply with the process
vent emission limits. This proposed change streamlines all closed vent
system requirements within the rule by preventing an owner or operator
from having to comply with more than one set of closed vent system
requirements (e.g., the current rule requires owners or operators of
equipment to comply with the closed vent system requirements at 40 CFR
63.983 pursuant to 40 CFR 63.1034, yet owners or operators of a process
vent must comply with the closed vent system requirements at 40 CFR
63.11930). Also, this proposed change (i.e., to comply with 40 CFR
63.11930 for affected sources that route emissions from equipment in
HAP service through a closed vent system to a control device, or back
into the process or a fuel gas system) would not allow the affected
source to bypass the air pollution control device at any time, and if a
bypass is used, then the affected source would be required to estimate
and report the quantity of vinyl chloride and total HAP released (see
40 CFR 63.11930(c) and 40 CFR 63.11985(b)(10), respectively). We are
proposing this change because bypassing an air pollution control device
could result in a release of regulated 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 at 40 CFR 63.11930(c) that any open-
ended valve or line in the closed vent system that is equipped with a
cap, blind flange, plug, or second valve which operates to seal the
line at all times is not subject to the bypass requirements.
    Finally, we are proposing at 40 CFR 63.11915(e) to make references
that are related to startup, shutdown, and malfunction (SSM) exemptions
for equipment leak requirements in 40 CFR part 63, subparts SS and UU,
no longer applicable. Consistent with Sierra Club v. EPA, we are
proposing standards in this rule that apply at all times. In its 2008
decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), the
court vacated portions of two provisions in the EPA's CAA section 112
regulations governing the emissions of HAP during periods of SSM.
Specifically, the court vacated the SSM exemptions contained in 40 CFR
63.6(f)(1) and (h)(1), holding that under section 302(k) of the CAA,
emissions standards or limitations must be continuous in nature and
that the SSM exemptions violate the CAA's requirement that CAA section
112 standards apply continuously.
    The EPA is soliciting comment on all of the proposed changes
discussed in this section of the preamble (i.e., proposed changes to
the equipment leak requirements in 40 CFR 63.11915). We note that all
of these proposed changes are also being proposed for the 2012 area
source rule at 40 CFR 63.11142(f)(6) because 40 CFR 63.11915 is
referenced in those requirements. Given that owners and operators are
already complying with the control device and closed vent system
requirements for process vents, we estimate that there would be no
impact on any facility for making these changes. In other words, if the
affected source chooses to route emissions from equipment in HAP
service through a closed vent system to a control device (to comply
with the equipment leak standards), we believe the affected source is
likely to use the same existing closed vent system and control device
being used to comply with the process vent standards.

G. Closed Vent Systems

    We are proposing amendments to the closed vent system requirements
in 40 CFR 63.11930 that clarify applicability. The requirement at 40
CFR 63.11930(a) is misleading because it states that the closed vent
system requirements in 40 CFR 63.11930 are exclusively for closed vent
systems used to route emissions from process vents; however, as
specified elsewhere in the 2012 final major and area source rules,
closed vent systems used to route emissions from other sources (e.g.,
stripped resin, process wastewater, storage vessels) are also subject
to the closed vent system requirements in 40 CFR 63.11930. Therefore,
we are proposing to clarify 40 CFR 63.11930(a) to specify that if the
affected source uses a closed vent system to comply with an emission
limit in Table 1 or 2 to 40 CFR part 63, subpart DDDDDD, or an emission
limit in Table 1, 1b, 2, 2b, or 3 to 40 CFR part 63, subpart HHHHHHH,
or to comply with the requirements in 40 CFR 63.11910, 40 CFR 63.11915,
or 40 CFR 63.11955, then the affected source must comply with the
closed vent system requirements in 40 CFR 63.11930. In other words, our
proposal makes clear that if a closed vent system is being used to
comply with any of the PVC production standards (i.e., the process
vent, stripped resin, process wastewater, storage vessel, equipment
leak, or other emission source standards in 40 CFR part 63, subpart
DDDDDD or HHHHHHH), then 40 CFR 63.11930 applies. For the same reasons,
we are also proposing to amend 40 CFR 63.11930(b) (i.e., the
requirement that each closed vent system be designed and operated to
collect HAP vapors and route the collected vapors to a control device)
applies to all emission sources that route emissions through a closed
vent system to a control device, a fuel gas system, or process.
    The EPA is soliciting comment on all of the proposed changes
discussed in this section of the preamble (i.e., proposed changes to
the closed vent system requirements in 40 CFR 63.11930). We note that
all of these proposed changes are also being proposed for the 2012 area
source rule at 40 CFR 63.11142(f)(9) because 40 CFR 63.11930 is
referenced in those requirements. Given that owners and operators are
already complying with 40 CFR 63.11930 for emissions sources other than
process vents (e.g., stripped resin, process wastewater, and storage
tanks), we estimate that there would be no impact on any facility for
making this change.

H. Affirmative Defense

    In the 2012 final major and area source rules, the EPA included an
affirmative defense to civil penalties for violations caused by
malfunctions (see 40 CFR 63.11895) in an effort to create a system that
incorporated some flexibility, recognizing that there is a tension,
inherent in many types of air regulation, to ensure adequate compliance
while simultaneously recognizing that despite the most diligent of
efforts, emission standards may be violated under circumstances
entirely beyond the control of the source. Although the EPA recognized
that its case-by-case enforcement discretion provides sufficient
flexibility in these circumstances, it included the affirmative defense
to provide a more formalized approach and more regulatory clarity. See
Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 1978)
(holding that an informal case-by-case enforcement discretion approach
is adequate); but see Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73
(9th Cir. 1977) (requiring a more formalized approach to consideration
of ``upsets beyond the control of the permit holder.''). Under the
EPA's regulatory affirmative defense provisions, if a source could
demonstrate in a judicial or administrative proceeding that it had met
the requirements of the affirmative defense in the regulation, civil
penalties would not be assessed. However, the court vacated the
affirmative defense in one of the EPA's CAA section 112 regulations.
NRDC v. EPA, 749 F.3d 1055 (D.C. Cir., 2014) (vacating affirmative
defense provisions in the CAA section 112 rule establishing emission
standards for Portland cement kilns). The court found that the EPA
lacked authority to establish an affirmative defense for private civil
suits and held that under the CAA, the authority to determine civil
penalty amounts in such cases lies exclusively with the courts, not the
EPA. Specifically, the court found: ``As the language of the statute
makes clear, the courts determine, on a case-by-case basis, whether
civil penalties are `appropriate.''' See NRDC at 1063 (``[U]nder this
statute, deciding whether penalties are `appropriate' in a given
private civil suit is a job for the courts, not EPA.'').\15\ In light
of NRDC, the EPA is proposing to remove all of the regulatory
affirmative defense provisions from 40 CFR part 63, subpart DDDDDD
(i.e., the reference to ``Sec.  63.11895'' in 40 CFR 63.11142(f)(2)),
and 40 CFR part 63, subpart HHHHHHH (i.e., 40 CFR 63.11895 in its
entirety and all other rule text that references 40 CFR 63.11895). As
explained above, if a source is unable to comply with emissions
standards as a result of a malfunction, the EPA may use its case-by-
case enforcement discretion to provide flexibility, as appropriate.
Further, as the court recognized, in an EPA or citizen enforcement
action, the court has the discretion to consider any

defense raised and determine whether penalties are appropriate. Cf.
NRDC, at 1064 (arguments that violation was caused by unavoidable
technology failure can be made to the courts in future civil cases when
the issue arises). The same is true for the presiding officer in EPA
administrative enforcement actions.\16\
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    \15\ The court's reasoning in NRDC focuses on civil judicial
actions. The court noted that ``EPA's ability to determine whether
penalties should be assessed for CAA violations extends only to
administrative penalties, not to civil penalties imposed by a
court.'' Id.
    \16\ Although the NRDC case does not address the EPA's authority
to establish an affirmative defense to penalties that are available
in administrative enforcement actions, we are not including such an
affirmative defense in the proposed rule. As explained above, such
an affirmative defense is not necessary. Moreover, assessment of
penalties for violations caused by malfunctions in administrative
proceedings and judicial proceedings should be consistent. Cf. CAA
section 113(e) (requiring both the Administrator and the court to
take specified criteria into account when assessing penalties).
---------------------------------------------------------------------------

I. Other Technical Corrections and Clarifications

    There are a number of additional revisions that we are proposing to
40 CFR part 63, subpart DDDDDD, and 40 CFR part 63, subpart HHHHHHH, to
clarify text and correct typographical errors, grammatical errors, and
cross-reference errors; and we request public comment on these
revisions. These proposed editorial corrections and clarifications are
summarized in Table 6 of this preamble. We note that although these
proposed changes are being made directly in the major source rule, many
of these proposed changes also result in revisions to the area source
rule because 40 CFR part 63, subpart DDDDDD, references provisions in
40 CFR part 63, subpart HHHHHHH.

 Table 6--Summary of Proposed Editorial and Minor Corrections to 40 CFR
       Part 63, Subpart DDDDDD and 40 CFR Part 63, Subpart HHHHHHH
------------------------------------------------------------------------
                                                         40 CFR part 63,
    40 CFR part 63, subpart        Proposed revision     subpart DDDDDD
       HHHHHHH provision                                  provision \1\
------------------------------------------------------------------------
Not applicable................  Replace ``are           40 CFR
                                 considered an           63.11140(b)(3).
                                 existing affected
                                 source'' with ``must
                                 comply with
                                 paragraphs (b)(3)(i)
                                 and (ii) of this
                                 section'' to clarify
                                 requirements.
40 CFR 63.11872...............  Revise heading to       Not applicable.
                                 ``What is the
                                 relationship to other
                                 regulations?'' to
                                 clarify content of 40
                                 CFR 63.11872.
                                Clarify that 40 CFR
                                 part 63, subpart J,
                                 does not apply to any
                                 source that is
                                 subject to the
                                 requirements of this
                                 subpart. 40 CFR part
                                 63, subpart J, was
                                 vacated by court
                                 action.
40 CFR 63.11896(b)............  Revise first sentence   40 CFR
                                 to be consistent with   63.11142(f)(3).
                                 the same phrasing
                                 used in 40 CFR
                                 63.11896(a).
40 CFR 63.11900(c)............  Replace ``the           40 CFR
                                 effective date of       63.11142(f)(4).
                                 publication of the
                                 final rule in the
                                 Federal Register''