[Federal Register Volume 85, Number 133 (Friday, July 10, 2020)]
[Rules and Regulations]
[Pages 41680-41714]
[FR Doc No: 2020-05896]

Vol. 85

Friday,

No. 133

July 10, 2020

Part II

Environmental Protection Agency

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40 CFR Part 63

National Emission Standards for Hazardous Air Pollutants: Site
Remediation Residual Risk and Technology Review; Final Rule

Federal Register / Vol. 85, No. 133 / Friday, July 10, 2020 / Rules
and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2018-0833; FRL-10006-94-OAR]
RIN 2060-AU19

National Emission Standards for Hazardous Air Pollutants: Site
Remediation Residual Risk and Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action finalizes the residual risk and technology review
(RTR) conducted for the Site Remediation source category regulated
under national emission standards for hazardous air pollutants
(NESHAP). The U.S. Environmental Protection Agency (EPA) is finalizing
the proposed determination that risks due to emissions of air toxics
from site remediation sources are acceptable and that no revision to
the standards is required to provide an ample margin of safety to
protect public health. Based on the results of our technology review,
we are promulgating the proposed changes to the leak detection and
repair (LDAR) program. In addition, the EPA is finalizing amendments to
revise regulatory provisions pertaining to emissions during periods of
startup, shutdown and malfunction (SSM), including finalizing work
practice requirements for pressure relief devices (PRDs) and the 240-
hour maintenance period for control devices on tanks. We are finalizing
requirements for electronic submittal of semiannual reports and
performance test results. Finally, we are making minor clarifications
and corrections. The final revisions to the rule will increase the
level of emissions control and environmental protection provided by the
Site Remediation NESHAP.

DATES: This final rule is effective on July 10, 2020. The incorporation
by reference (IBR) of certain publications listed in the rule is
approved by the Director of the Federal Register as of July 10, 2020.

ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2018-0833. All documents in the docket are
listed on the https://www.regulations.gov/ website. Although listed,
some information is not publicly available, e.g., Confidential Business
Information or other information whose disclosure is restricted by
statute. Certain other material, such as copyrighted material, is not
placed on the internet and will be publicly available only in hard copy
form. Publicly available docket materials are available either
electronically through https://www.regulations.gov/, or in hard copy at
the EPA Docket Center, WJC West Building, Room Number 3334, 1301
Constitution Ave. NW, Washington, DC. The Public Reading Room hours of
operation are 8:30 a.m. to 4:30 p.m., Eastern Standard Time (EST)
Monday through Friday. The telephone number for the Public Reading Room
is<PHONE_NUMBER>, and the telephone number for the EPA Docket Center
is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: For questions about this final action,
contact Matthew Witosky, Sector Policies and Programs Division (E143-
05), 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>For specific information regarding
the risk modeling methodology, contact Matthew Woody, Health and
Environmental Impacts Division (C539-02), Office of Air Quality
Planning and Standards, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina 27711; telephone number:<PHONE_NUMBER>;
fax number:<PHONE_NUMBER>; and email address<EMAIL_ADDRESS>
For information about the applicability of the NESHAP to a particular
entity, contact Marcia Mia, Office of Enforcement and Compliance
Assurance, U.S. Environmental Protection Agency, WJC South Building
(Mail Code 2227A), 1200 Pennsylvania Avenue NW, Washington DC 20460;
telephone number:<PHONE_NUMBER>; and email address:
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:
    Preamble acronyms and abbreviations. We use multiple acronyms and
terms in this preamble. While this list may not be exhaustive, to ease
the reading of this preamble and for reference purposes, the EPA
defines the following terms and acronyms here:

ACC American Chemistry Council
ADAF age-dependent adjustment factors
API American Petroleum Institute
APR amino and phenolic resins
ASTM American Society for Testing and Materials
CAA Clean Air Act
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CRA Congressional Review Act
EFH Exposure Factors Handbook
EPA Environmental Protection Agency
EtO ethylene oxide
HAP hazardous air pollutant(s)
HCl hydrochloric acid
NEI National Emissions Inventory
HHRAP Human Health Risk Assessment Protocol
HI hazard index
HQ hazard quotient
IARC International Agency for Research on Cancer
IBR incorporation by reference
ICR Information Collection Request
LDAR leak detection and repair
MACT maximum achievable control technology
MIR maximum individual risk
NAICS North American Industry Classification System
NESHAP national emission standards for hazardous air pollutants
NTTAA National Technology Transfer and Advancement Act
OEHHA California Office of Environmental Health Hazard Assessment
OEL open-ended line
OMB Office of Management and Budget
PAH polycyclic aromatic hydrocarbon
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PCDDs polychlorinated dibenzodioxins
PCDFs polychlorinated dibenzofurans
POM polycyclic organic matter
ppm parts per million
ppmw parts per million by weight
PRD pressure relief device
REL reference exposure level
RFA Regulatory Flexibility Act
RMMU remediation material management unit
RTR residual risk and technology review
SAB Science Advisory Board
SSM startup, shutdown, and malfunction
TOSHI target organ-specific hazard index
tpy tons per year
UMRA Unfunded Mandates Reform Act

    Background information. On September 3, 2019, the EPA proposed
revisions to the Site Remediation NESHAP based on our RTR. In this
action, we are finalizing decisions and revisions for the rule. We
summarize some of the more significant comments we timely received
regarding the proposed rule and provide our responses in this preamble.
A summary of all other public comments on the proposal and the EPA's
responses to those comments is available in the National Emission
Standards for Hazardous Air Pollutant Emissions: Site Remediation
Summary of Public Comments and Responses on Proposed Rule (84 FR 46138;
September 3, 2019), Docket ID No. EPA-HQ-OAR-2018-0833. A ``track
changes'' version of the regulatory language that incorporates the
changes in this action is available in the docket.
    Organization of this document. The information in this preamble is
organized as follows:

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

I. General Information

A. Does this action apply to me?

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

 Table 1--NESHAP and Industrial Source Categories Affected by This Final
                                 Action
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        Source category               NESHAP           NAICS code \1\
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Industry......................  40 CFR part 63,    325211
                                 subpart GGGGG.    325192
                                                   325188
                                                   32411
                                                   49311
                                                   49319
                                                   48611
                                                   42269
                                                   42271
Federal Government............  .................  Federal agency
                                                    facilities that
                                                    conduct Site
                                                    Remediation
                                                    activities.
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\1\ North American Industry Classification System.

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

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

    In addition to being available in the docket, an electronic copy of
this final action will also be available on the internet. Following
signature by the EPA Administrator, the EPA will post a copy of this
final action at: https://www.epa.gov/stationary-sources-air-pollution/siteremediation-national-emissionstandards-hazardous-air. Following
publication in the Federal Register, the EPA will post the Federal
Register version and key technical documents at this same website.
    Additional information is available on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/risk-and-technology-review-national-emissions-standards-hazardous. This information
includes an overview of the RTR program and links to project websites
for the RTR source categories.

C. Judicial Review and Administrative Reconsideration

    Under Clean Air Act (CAA) section 307(b)(1), judicial review of
this final action is available only by filing a petition for review in
the United States Court of Appeals for the District of Columbia Circuit
(the Court) by September 8, 2020. Under CAA section 307(b)(2), the
requirements established by this final rule may not be challenged
separately in any civil or criminal proceedings brought by the EPA to
enforce the requirements.
    Section 307(d)(7)(B) of the CAA further provides that only an
objection to a rule or procedure which was raised

with reasonable specificity during the period for public comment
(including any public hearing) may be raised during judicial review.
This section also provides a mechanism for the EPA to reconsider the
rule if the person raising an objection can demonstrate to the
Administrator that it was impracticable to raise such objection within
the period for public comment or if the grounds for such objection
arose after the period for public comment (but within the time
specified for judicial review) and if such objection is of central
relevance to the outcome of the rule. Any person seeking to make such a
demonstration should submit a Petition for Reconsideration to the
Office of the Administrator, U.S. EPA, Room 3000, WJC South Building,
1200 Pennsylvania Ave. NW, Washington, DC 20460, with a copy to both
the person(s) listed in the preceding FOR FURTHER INFORMATION CONTACT
section, and the Associate General Counsel for the Air and Radiation
Law Office, Office of General Counsel (Mail Code 2344A), U.S. EPA, 1200
Pennsylvania Ave. NW, Washington, DC 20460.

II. Background

A. What is the statutory authority for this action?

    Section 112 of the CAA establishes a two-stage regulatory process
to address emissions of hazardous air pollutants (HAP) from stationary
sources. In the first stage, we must identify categories of sources
emitting one or more of the HAP listed in CAA section 112(b) and then
promulgate technology-based NESHAP for those sources. ``Major sources''
are those that emit, or have the potential to emit, any single HAP at a
rate of 10 tons per year (tpy) or more, or 25 tpy or more of any
combination of HAP. For major sources, these standards are commonly
referred to as maximum achievable control technology (MACT) standards
and must reflect the maximum degree of emission reductions of HAP
achievable (after considering cost, energy requirements, and non-air
quality health and environmental impacts). In developing MACT
standards, CAA section 112(d)(2) directs the EPA to consider the
application of measures, processes, methods, systems, or techniques,
including, but not limited to, those that reduce the volume of or
eliminate HAP emissions through process changes, substitution of
materials, or other modifications; enclose systems or processes to
eliminate emissions; collect, capture, or treat HAP when released from
a process, stack, storage, or fugitive emissions point; are design,
equipment, work practice, or operational standards; or any combination
of the above.
    For these MACT standards, the statute specifies certain minimum
stringency requirements, which are referred to as MACT floor
requirements, and which may not be based on cost considerations. See
CAA section 112(d)(3). For new sources, the MACT floor cannot be less
stringent than the emission control achieved in practice by the best-
controlled similar source. The MACT standards for existing sources can
be less stringent than floors for new sources, but they cannot be less
stringent than the average emission limitation achieved by the best-
performing 12 percent of existing sources in the category or
subcategory (or the best-performing five sources for categories or
subcategories with fewer than 30 sources). In developing MACT
standards, we must also consider control options that are more
stringent than the floor under CAA section 112(d)(2). We may establish
standards more stringent than the floor, based on the consideration of
the cost of achieving the emissions reductions, any non-air quality
health and environmental impacts, and energy requirements.
    In the second stage of the regulatory process, the CAA requires the
EPA to undertake two different analyses, which we refer to as the
technology review and the residual risk review. Under the technology
review, we must review the technology-based standards and revise them
``as necessary (taking into account developments in practices,
processes, and control technologies)'' no less frequently than every 8
years, pursuant to CAA section 112(d)(6). Under the residual risk
review, we must evaluate the risk to public health remaining after
application of the technology-based standards and revise the standards,
if necessary, to provide an ample margin of safety to protect public
health or to prevent, taking into consideration costs, energy, safety,
and other relevant factors, an adverse environmental effect. The
residual risk review is required within 8 years after promulgation of
the technology-based standards, pursuant to CAA section 112(f). In
conducting the residual risk review, if the EPA determines that the
current standards provide an ample margin of safety to protect public
health, it is not necessary to revise the MACT standards pursuant to
CAA section 112(f).\1\ For more information on the statutory authority
for this rule, see 84 FR 46138 (September 3, 2019).
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    \1\ The Court has affirmed this approach of implementing CAA
section 112(f)(2)(A): NRDC v. EPA, 529 F.3d 1077, 1083 (DC Cir.
2008) (``If EPA determines that the existing technology-based
standards provide an 'ample margin of safety,' then the Agency is
free to readopt those standards during the residual risk
rulemaking.'').
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B. What is the Site Remediation source category and how does the NESHAP
regulate HAP emissions from the source category?

    The EPA promulgated the final Site Remediation NESHAP at 68 FR
58172 (October 8, 2003). The NESHAP applies to ``remediation
material.'' Site remediation means one or more activities or processes
used to remove, destroy, degrade, transform, immobilize, or otherwise
manage remediation material. Monitoring or measuring of contamination
levels in media, whether by using wells, sampling, or other means, is
not considered to be a Site Remediation. The rule applies only to
active remedial operations at sites that are major sources with
affected facilities subject to another MACT standard. The Site
Remediation NESHAP applies to various types of affected sources
including process vents, remediation material management units, and
equipment leaks. The affected source for process vents is the entire
group of process vents associated with the in-situ and ex-situ
remediation processes used at the site to remove, destroy, degrade,
transform, or immobilize hazardous substances in the remediation
material. Examples of process vents for in-situ remediation processes
include the discharge vents to the atmosphere used for soil vapor
extraction and underground bioremediation processes. Examples of
process vents for ex-situ remediation processes include vents for
thermal desorption, bioremediation, and stripping processes (air or
steam stripping). The affected source for remediation material
management units is the entire group of tanks, surface impoundments,
containers, oil-water separators, and transfer systems used for the
Site Remediation activities involving clean-up of remediation material.
The affected source for equipment leaks is the entire group of
remediation equipment components (pumps, valves, etc.) that is intended
to operate for 300 hours or more during a calendar year in remediation
material service and that contains or contacts remediation material
having a concentration of regulated HAP equal to or greater than 10
percent by weight.
    The Site Remediation MACT standards include a combination of
equipment standards, work practice standards, operational standards,
and performance standards for each of the

affected emission sources noted above. The source category covered by
this MACT standard currently includes approximately 30 facilities.

C. What changes did we propose for the Site Remediation source category
in our September 3, 2019, proposal?

    On September 3, 2019, the EPA published proposed amendments in the
Federal Register for the Site Remediation NESHAP, 40 CFR part 63,
subpart GGGGG, that took into consideration the RTR analyses and also
proposed other revisions. The proposed revisions included the
following:
     Revisions to the equipment leak requirements to require
the use of the leak detection thresholds of 40 CFR part 63, subpart UU
for valves and pumps, rather than the thresholds of 40 CFR part 63,
subpart TT;
     Revisions to requirements related to emissions during
periods of SSM;
     The addition of requirements for electronic submittal of
semiannual reports and performance tests;
     Removal of the 240-hour exemption from control
requirements for planned routine maintenance of emissions control
systems;
     Clarifications to the ``sealed'' requirement of the
provisions for open-ended lines (OELs);
     Addition of work practice and monitoring requirements for
PRDs; and
     Several minor clarifications and corrections.

D. What other actions did we take for the Site Remediation source
category in our September 3, 2019, proposal?

    Within the RTR proposal, the EPA separately solicited comment on
ways in which the Site Remediation NESHAP could be amended with respect
to facilities currently exempt under 40 CFR 63.7881(b)(2) and (3),
under a scenario where the EPA removes the exemption. The exemption
applies to facilities subject to federally-enforceable oversight under
the Resource Conservation and Recovery Act (RCRA) or the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA). In
particular, in light of comments received on our 2016 proposal to
remove the exemption, the Agency sought additional comment regarding
subcategorization or other methods of distinguishing among appropriate
requirements for such sources. We explained our intention to use this
opportunity to gather additional information in anticipation of
addressing these issues through a separate action.

III. What is included in this final rule?

    This action finalizes the EPA's determinations pursuant to the RTR
provisions of CAA section 112 for the Site Remediation source category
and amends the SR NESHAP based on those determinations. We are also
finalizing other proposed changes to the NESHAP and other changes made
in consideration of comments received during the public comment period
for the proposed rulemaking. In the following subsections, we summarize
the final amendments to the Site Remediation NESHAP.
    We are not finalizing any changes at this time to the exemption
from the Site Remediation NESHAP requirements available for federally-
overseen Site Remediations under RCRA or CERCLA, pursuant to 40 CFR
63.7881(b)(2) and (3). The agency is continuing to review comments
related to our solicitation on this issue in the RTR proposal, see 84
FR 46167-69 (September 3, 2019), and comments on the May 13, 2016,
proposal regarding the exemption (81 FR 29812), and intends to address
this issue in a separate action.

A. What are the final rule amendments based on the risk review for the
Site Remediation source category?

    For the Site Remediation source category, we have determined that
the current NESHAP reduces risk to an acceptable level, provides an
ample margin of safety to protect public health, and prevents adverse
environmental effects. Therefore, as we proposed, it is not necessary
to revise the NESHAP pursuant to CAA section 112(f).

B. What are the final rule amendments based on the technology review
for the Site Remediation source category?

    We have determined that there have been developments in practices,
processes, and control technologies that warrant revisions to the Site
Remediation NESHAP. Therefore, to satisfy the requirements of CAA
section 112(d)(6), and as we proposed, we are revising the NESHAP to
require facilities to use the leak detection thresholds of 40 CFR part
63, subpart UU for valves and pumps, rather than those of 40 CFR part
63, subpart TT. For other Site Remediation emissions sources, we have
determined that, as we proposed, there are no viable developments in
HAP emission reduction practices, processes, or control technologies to
apply, considering the technical feasibility, estimated costs, and
emission reductions of the options identified.

C. What are the final rule amendments pursuant to CAA section 112(d)(2)
and (3) for the Site Remediation source category?

    Consistent with the Court's ruling in Sierra Club v. EPA, 551 F.3d
1019 (D.C. Cir. 2008), we are finalizing the proposed requirements,
with two minor modifications, for safety devices, bypasses and closure
devices on pressure tanks, and PRDs to ensure a standard continuously
applies during malfunctions that result in an emissions release
directly to the atmosphere (i.e., an actuation event). These final
requirements include work practices that consist of conducting an
analysis of the cause of a PRD actuation event and the implementation
of corrective measures. In addition, we are finalizing the proposed
criteria for what constitutes a deviation from the work practice
requirements. We are also finalizing the proposed requirement that PRDs
be monitored with a device or monitoring system that is capable of (1)
identifying the pressure release; (2) recording the time and duration
of each pressure release; and (3) notifying operators immediately that
a pressure release is occurring. Finally, we are finalizing the
proposed recordkeeping and reporting requirements associated with
releases to the atmosphere from bypasses and PRDs.
    In response to comments received on the proposed rule, we are
making two modifications to the proposed requirements and one change to
the estimate of costs associated with PRD monitoring. One modification
is to exclude PRDs on containers from the PRD work practice standards
and monitoring requirements, and the other modification is to clarify
when a PRD is subject to LDAR requirements and when a PRD is subject to
the PRD actuation event work practice requirements. We have also
revised the economic analysis for the adoption of the proposed PRD
monitoring requirements to reflect the purchase of monitoring equipment
for some facilities rather than assuming all facilities already have
adequate monitoring systems.

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

    With one exception, we are finalizing changes to the Site
Remediation NESHAP to eliminate the SSM exemption as proposed.
Consistent with Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008),
the EPA has established standards in this rule that apply at all times.
Table 3 to Subpart GGGGG of Part 63 (General Provisions applicability

table) is being revised to change several references related to
requirements that apply during periods of SSM. We also eliminated or
revised certain recordkeeping and reporting requirements related to the
eliminated SSM exemption. The EPA also made changes to the rule to
remove or modify inappropriate, unnecessary, or redundant language in
the absence of the SSM exemption. We determined that facilities in this
source category can meet the applicable emission standards in the Site
Remediation NESHAP at all times, including periods of startup and
shutdown; therefore, the EPA determined that no additional standards
are needed to address emissions during these periods.
    In response to comments received on the proposed rule, the EPA is
making a change to the 240-hour annual control system bypass allowance
for planned routine maintenance of a closed vent system or control
device. Rather than remove this allowance for all control systems, the
final rule will retain the allowance with the addition of a work
practice requirement for storage tank control devices and closed vent
systems.

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

    This rule also finalizes revisions to several other Site
Remediation NESHAP requirements. We describe the revisions in the
following paragraphs.
    To increase the ease and efficiency of data submittal and data
accessibility, we are finalizing, as proposed, a requirement that
owners or operators of site remediation facilities submit electronic
copies of required performance test reports, performance evaluation
reports, and semi-annual compliance reports through the EPA's Central
Data Exchange (CDX) using the Compliance and Emissions Data Reporting
Interface (CEDRI).
    As proposed, the EPA is not establishing emission standards for
inorganic or metal HAP.
    Based on comments received on the proposed provisions for OELs, we
are not finalizing the proposed language in the Site Remediation NESHAP
that OELs are ``sealed'' by a cap, blind flange, plug or second valve
when instrument monitoring of the OEL conducted according to EPA Method
21 of 40 CFR part 60, appendix A indicates no readings of 500 parts per
million (ppm) or greater. Since OELs are present at many facilities,
additional consideration of the proposed change would be appropriate
because there are multiple source categories that cross-reference the
same equipment and operational requirements for OELs. We continue to
believe it is important that the standard to seal the OEL includes a
clear mechanism for a source to demonstrate compliance with that
requirement. Therefore, the EPA intends to continue to evaluate
appropriate means of compliance certainty for OELs, including the term
``sealed,'' and is not finalizing any revisions to the OEL standards
applicable to Site Remediation in this action. The EPA emission
estimates used in the risk modeling are based on reported emissions and
we did not estimate HAP reductions from the proposed approach. For this
reason, this decision not to finalize the OEL provisions does not alter
our analysis of estimated emissions, risks, and decisions related to
risk.
    We are finalizing, as proposed, several miscellaneous minor changes
to improve the clarity of the rule requirements.

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

    The revisions to the MACT standards being promulgated in this
action are effective on July 10, 2020.
    The compliance date for existing affected sources for the revised
SSM requirements is 180 days after the effective date of the standard,
January 6, 2021. The requirements for electronic reporting
requirements, the revised routine maintenance provisions, the operating
and pressure management requirements for PRDs, and the revised
requirements regarding bypasses and closure devices on pressure tanks
is 180 days after the effective date of the standard, January 6, 2021.
    For electronic reporting, we have experience with similar
industries shows that a time period of a minimum of 90 days, and more
typically 180 days, is generally necessary to successfully complete the
changes required to convert reporting mechanisms, including the
installation of the necessary hardware and software, becoming familiar
with the process of submitting performance test results electronically
through the EPA's CEDRI, testing these new electronic submission
capabilities, reliably employing electronic reporting, and converting
the logistics of reporting processes to different time-reporting
parameters.
    We are finalizing the 180-day compliance date for the other
requirements listed above for existing affected sources because we are
finalizing changes to the requirements for SSM by removing the
exemption from the requirements to meet a standard during SSM periods
and by removing the requirement to develop and implement an SSM plan,
as proposed. We have experience with similar industries further shows
that this sort of regulated facility generally requires a time period
of 180 days to read and understand the amended rule requirements;
evaluate their operations to ensure that they can meet the standards
during periods of SSM; adjust parameter monitoring and recording
systems to accommodate revisions; and update their operations to
reflect the revised requirements.
    The compliance date for existing affected sources to comply with
the new PRD actuation work practice standard, including monitoring
requirement and actuation event reporting requirements, under 40 CFR
63.7923 is 18 months from the effective date of the final amendment,
January 10, 2022. This time period will allow Site Remediation facility
owners and operators to research equipment and vendors, and to
purchase, install, test, and properly operate any necessary equipment
by the compliance date.
    For equipment leaks, the compliance date for existing affected
sources is 1 year from the effective date of the standards, July 10,
2021. This time period is necessary to allow existing affected sources
that are currently complying with 40 CFR part 63, subpart TT, adequate
time to modify their existing LDAR programs to comply with the revised
standards for pumps and valves.
    New affected sources must comply with all of the standards and
requirements of the amended rule immediately upon the effective date of
the final amendments, July 10, 2020, or upon startup, whichever is
later.

IV. What is the rationale for our final decisions and amendments for
the Site Remediation source category?

    For each issue, this section provides a description of what we
proposed and what we are finalizing for the issue, the EPA's rationale
for the final decisions and amendments, and a summary of key comments
and responses. For all comments not discussed in this preamble, comment
summaries and the EPA's responses can be found in the comment summary
and response document available in the docket (Docket ID No. EPA-HQ-
OAR-2018-0833).

A. Residual Risk Review for the Site Remediation Source Category

1. What did we propose pursuant to CAA section 112(f) for the Site
Remediation source category?
    Pursuant to CAA section 112(f), we conducted a residual risk
assessment for both affected sources and sources exempt from Site
Remediation NESHAP requirements pursuant to 40 CFR 63.7881(b)(2) or (3)
(i.e., ``RCRA/CERCLA-exempt sources'') and presented the results of
these assessments separately, along with our proposed decisions
regarding risk acceptability and ample margin of safety for affected
sources, in the September 3, 2019, RTR proposal (84 FR 46138).\2\ The
residual risk assessments for the Site Remediation source category
included assessment of cancer risk, chronic noncancer risk, and acute
noncancer risk due to inhalation exposure, as well as multipathway
exposure risk and environmental risk. The results of the risk
assessment for affected sources are presented briefly below in Table 2
of this preamble and in more detail in the residual risk document,
Residual Risk Assessment for the Site Remediation Source Category in
Support of the 2020 Risk and Technology Review Final Rule, which is
available in the docket for this rulemaking. The results of the risk
assessment for the RCRA/CERCLA-exempt sources are presented briefly
below in Table 3 of this preamble and in more detail in the residual
risk document, Residual Risk Assessment for Exempt Sources in the Site
Remediation Source Category in Support of the 2020 Risk and Technology
Review Final Rule, which is available in the docket for this
rulemaking.
---------------------------------------------------------------------------

    \2\ The risk assessment for exempt sources, while not
characterized as a risk acceptability analysis, provides all of the
necessary data in order to complete a risk acceptability
determination.
---------------------------------------------------------------------------

    The results of the assessment for affected sources indicated that
maximum inhalation cancer risk to the individual most exposed is 1-in-1
million based on actual and allowable emissions (actual emissions were
assumed to equal allowable emissions), which is well below the
presumptive limit of acceptability (i.e., 100-in-1 million). The total
estimated cancer incidence based on actual and allowable emission
levels is 0.001 excess cancer case per year, or 1 case every 1,000
years. In addition, the maximum chronic noncancer target organ specific
hazard index (TOSHI) due to inhalation exposures is less than 1. The
evaluation of acute noncancer risk, which was conservative, showed a
maximum hazard quotient (HQ) of 1 for all Site Remediation facilities.
Based on the results of the screening analyses for human multipathway
exposure to, and environmental impacts from HAP known to be persistent
and bio-accumulative in the environment (PB-HAP), we also concluded
that the risks to the individual most exposed through ingestion is
below the level of concern and no ecological benchmarks are exceeded.
The facility-wide cancer and noncancer risks were estimated based on
the actual emissions from all emissions sources at site remediation
facilities, including those not within the Site Remediation source
category. For facility-wide emissions, the maximum lifetime individual
cancer risk to the individual most exposed is 1,000-in-1 million from
ethylene oxide (EtO) and the noncancer TOSHI is 5.

                                    Table 2--Site Remediation Inhalation Risk Assessment Results for Affected Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Estimated  population
                                    Maximum  individual     at  increased risk of       Estimated annual         Maximum chronic       Maximum screening
    Number of  facilities \1\        cancer risk  (in 1        cancer >= 1-in-1         cancer incidence         noncancer TOSHI       acute  noncancer
                                          million)                 million              (cases per year)                                      HQ
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                            Based on Actual Emissions Level 2 3
                                 -----------------------------------------------------------------------------------------------------------------------
102.............................                        1                      400                    0.001                      0.1  HQREL = 1 (arsenic
                                                                                compounds).
                                 -----------------------------------------------------------------------------------------------------------------------
                                                                             Based on Whole Facility Emissions
                                 -----------------------------------------------------------------------------------------------------------------------
                                                    1,000                2,300,000                      0.5                        5  ..................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\3\ Actual emissions equal allowable emissions; therefore, actual risks equal allowable risks.

    The results of the assessment for RCRA/CERCLA-exempt sources
indicated that maximum inhalation cancer risk to the individual most
exposed is 4-in-1 million based on actual emissions and allowable
emissions (actual emissions were assumed to equal allowable emissions),
which is well below the presumptive limit of acceptability (i.e., 100-
in-1 million). The total estimated cancer incidence based on actual and
allowable emission levels is 0.001 excess cancer cases per year, or 1
case every 1,000 years. In addition, the maximum chronic noncancer
TOSHI due to inhalation exposures is less than 1. The evaluation of
acute noncancer risk, which was conservative, showed a maximum HQ less
than 1 for all of these site remediation facilities. Based on the
results of the screening analyses for human multipathway exposure to,
and environmental impacts from, PB-HAP, we also concluded that the
risks to the individual most exposed through ingestion is below the
level of concern and no ecological benchmarks are exceeded. The
facility-wide cancer and noncancer risks were estimated based on the
actual emissions from all emissions sources at site remediation
facilities, including those not within the Site Remediation source
category. For facility-wide emissions, maximum lifetime individual
cancer risk to the individual most exposed is 2,000-in-1 million from
EtO and the noncancer TOSHI is 7.

                                     Table 3--Site Remediation Inhalation Risk Assessment Results for Exempt Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Estimated  population
                                    Maximum  individual     at  increased risk of       Estimated annual         Maximum chronic       Maximum screening
    Number of  facilities \1\        cancer risk  (in 1        cancer >= 1-in-1         cancer incidence         noncancer TOSHI       acute  noncancer
                                          million)                 million              (cases per year)                                      HQ
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                            Based on Actual Emissions Level 2 3
                                 -----------------------------------------------------------------------------------------------------------------------
118.............................                        4                    1,100                    0.001                      0.3  <1
                                 -----------------------------------------------------------------------------------------------------------------------
                                                                             Based on Whole Facility Emissions
                                 -----------------------------------------------------------------------------------------------------------------------
                                                    2,000                9,000,000                        1                        7  ..................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from exempt sources in the source category.
\3\ Actual emissions equal allowable emissions; therefore, actual risks equal allowable risks.

    We weighed all health risk factors for affected sources, including
those shown in Table 2 of this preamble, in our risk acceptability
determination and proposed that the residual risks from the Site
Remediation source category are acceptable (84 FR 46157; September 3,
2019).
    We then considered whether 40 CFR part 63, subpart GGGGG, provides
an ample margin of safety to protect public health and prevents, taking
into consideration costs, energy, safety, and other relevant factors,
an adverse environmental effect. In considering whether the standards
should be tightened to provide an ample margin of safety to protect
public health, we considered the same risk factors that we considered
for our acceptability determination and also considered the costs,
technological feasibility, and other relevant factors related to
emissions control options that might reduce risk associated with
emissions from the source category.
    In our ample margin of safety analysis, we identified three control
options that could further reduce HAP emissions from the source
category. These control options included requiring a higher emissions
reduction efficiency for process vents, requiring more stringent leak
definition thresholds for certain equipment as part of the currently
required LDAR program, and requiring connector monitoring as part of
the currently required LDAR program. For these control options, we
proposed that the costs were not reasonable in light of the minimal
risk reduction that would be achieved, and these additional HAP
emissions controls are not necessary to provide an ample margin of
safety to protect public health (84 FR 46158; September 3, 2019).
2. How did the risk review change for the Site Remediation source
category?
    We have not changed any aspect of the risk assessment since the
September 2019 proposal for this source category.
3. What key comments did we receive on the risk review, and what are
our responses?
    Most of the commenters on the proposed risk review supported our
risk acceptability and ample margin of safety determinations for the
Site Remediation NESHAP. Some commenters requested that we make changes
to our residual risk review approach. However, we evaluated the
comments and determined that no changes to our risk assessment methods
or conclusions are warranted. A complete summary of these comments and
responses are in the comment summary and response document, available
in the docket for this action (Docket ID No. EPA-HQ-OAR-2018-0833). The
following is a summary of key comments we received regarding the risk
review and our responses to those comments.
    Comment: Several commenters agreed with the EPA's finding that
risks from the source category are acceptable, additional emissions
reductions are not needed to provide an ample margin of safety, and it
is not necessary to set more stringent standards to prevent an adverse
environmental effect. One of these commenters added that the risk
assessment results show very low risk from the source category.
However, another of these commenters asserted that even with the low
risk shown, the EPA's risk analysis overstates risk due to the
methodology the agency uses. This commenter said that the EPA's model
plant approach combined with data gap filling for most of the modeled
facilities results in a significant overestimation of HAP emissions.
The commenter also said that the EPA's conservative assumption that the
population breathes outdoor air at a fixed residential location for 70
years is an unrealistic assumption that needs to be modified. The
commenter pointed out that the California's Office of Environmental
Health Hazard Assessment (OEHHA) has revised their methodology for air
toxics assessment to use a 30-year residential exposure to identify the
maximum exposed individual for cancer risk assessment. Another of the
commenters remarked that the EPA should not have used the 70-year
exposure assumption for this source category, since Site Remediations
typically do not last more than 20 years. The commenter stated that the
EPA should have developed and used a factor representative of the
typical life of a remediation activity, which would have likely shown
even lower risk for the source category. One commenter also asserted
that the acute multiplier of 10 used to estimate hourly emissions from
annual emissions is not based on Site Remediation data and is a
standard EPA multiplier that is overly conservative.
    Response: The EPA relied on our standardized factor of 70 years for
our exposure factor.\3\ In this way the EPA has taken a health-
protective, or conservative, approach in estimating risks and has found
that the risks are acceptable and that the existing standards provide
an ample margin of safety to protect public health. Therefore, no
additional regulation was proposed based on risk for the category. For
this reason, there is no utility in refining the inputs to the risk
assessment to further lower the risk estimates.
---------------------------------------------------------------------------

    \3\ U.S. EPA. Exposure Factors Handbook, 2011 Edition (Final
Report). U.S. Environmental Protection Agency, Washington, DC, EPA/
600/R-09/052F, 2011.
---------------------------------------------------------------------------

    Comment: One commenter stated that the EPA only assessed EtO
emissions and risks in the facility-wide risk part of

its analysis, where the EPA finds risks of 1,000to 2,000-in-1 million.
The commenter stated that the EPA failed to justify ignoring EtO
emissions and resulting health risks from the Site Remediation source
category itself. The commenter asserted that the EPA ignored these
emissions because the six facilities it had data from did not show EtO
emissions, and the EPA believes EtO is unlikely to be emitted during a
Site Remediation due to its rapid decomposition. In contrast, the
commenter submitted that the monograph on EtO published by the
International Agency for Research on Cancer (IARC) suggests EtO has an
atmospheric half-life of 211 days. The commenter noted that the IARC
monograph goes on to state that data suggest neither rain nor
absorption into aqueous aerosols remove EtO from the atmosphere. The
commenter stated that the EPA has not provided sound rationale for
ignoring evidence of EtO emissions for this source category, and the
EPA statements on EtO's rapid decomposition in the environment are not
supported by credible scientific findings. The commenter claimed that
the EPA is relying on an American Chemistry Council (ACC) study that is
not available to the public in the online docket, undermining the
Agency's findings and violating the CAA's public notice-and-comment
requirements. The commenter explained that the referenced ACC study
relies upon a conceptual model that applied various data parameters to
determine potential adverse ecological risks and does not provide
information with respect to human health risks. The commenter contended
that the EPA may not rely on its underlying memorandum and this cited
study as the basis to not assess health risk from EtO emissions from
Site Remediations. The commenter said the EPA has not shown, based on
facts in the record, that there are no emissions and no health risks
from this chemical. The commenter also claimed that the EPA's proposal
that these emissions are unlikely to be emitted from the source
category does not make sense if EtO is emitted from other operations at
the sites. The commenter asserted that by refusing to assess the EtO-
based risk for this source category, the EPA has failed to satisfy the
CAA's requirement to assess and reduce such risk.
    Response: The data submitted by the commenter does not give the
Agency reason to change our position that EtO is unlikely to be a site
remediation pollutant. The half-life of a pollutant in the air is
irrelevant to whether EtO is a pollutant likely to be encountered in
Site Remediation material. The EPA stands by our assertion that EtO is
highly unlikely to persist in remediation material that would be
subject to Site Remediation NESHAP, (e.g., soil, water, sediment). This
assertion is further evidenced by the lack of any reported EtO
emissions in the EPA's National Emissions Inventory (NEI) from site
remediation operations. The commenter provided no data to contradict
this assertion.
    The EPA further disagrees that the sources cited by the commenter
do not provide sound rationale for removing EtO as a site remediation
pollutant. The EPA included two articles from peer-reviewed scientific
journals in the docket for the proposed rule to substantiate its
conclusion regarding EtO.\4\ The properties of EtO cited in the
proposal preamble were taken from these articles. In one article, the
fate of EtO in the environment was estimated using the EPI (Estimation
Program Interface) SuiteTM of modeling
programs.5 6 The individual estimation programs and/or their
underlying predictive methods and equations used within EPI
SuiteTM have been described in numerous peer-reviewed
technical journals. In addition, EPI SuiteTM has undergone
detailed review by a panel of the EPA's independent Science Advisory
Board (SAB), and its September 2007 report can be downloaded. The EPA
disagrees that the ACC study cited by the commenter is not in the
docket. While the document is not available for direct download from
the docket due to its copyright protection, it can be viewed in the EPA
Docket Center and is also available from other sources in the public
domain.
---------------------------------------------------------------------------

    \4\ See Docket ID Item Nos. EPA-HQ-OAR-2018-0833-0021 and EPA-
HQ-OAR-2018-0833-0022.
    \5\ Staples, C.A., & Gulledge, W. (2006). An environmental fate,
exposure and risk assessment of ethylene oxide from diffuse
emissions. Chemosphere, 65(4), 691-698. doi: 10.1016/
j.chemosphere.2006.01.047.
    \6\ EPI SuiteTM website: https://www.epa.gov/tsca-screening-tools/epi-suitetm-estimation-program-interface.
---------------------------------------------------------------------------

    Comment: One commenter asserted that the EPA's benchmarks for the
level of health risk that is considered acceptable are an outdated
policy that does not reflect subsequent scientific breakthroughs and
public perceptions of acceptable environmental health risks. The
commenter disagreed with the EPA's policy that a cancer risk of 100-in-
1 million is presumed to be either safe or acceptable, that for acute
risks an HQ less than 1 is always acceptable, and that an HQ greater
than 1 can be deemed acceptable without reasoned explanation. The
commenter stated that the EPA's acceptability benchmarks are based on a
1988 study of people's tolerance for various types of health risk,
known as the Survey of Societal Risk.\7\ The commenter remarked that
the EPA has failed to revisit or update this policy over the decades,
even though scientists have made breakthroughs on early-life exposure
and children's vulnerability; biomonitoring and other data on adult
body burdens of chemicals; the vulnerability of overburdened
communities, including socioeconomic disparities; and ways to analyze
and control the impacts of pollutants on human health. The commenter
listed 17 ``landmark'' actions from the EPA, other regulatory agencies,
and scientific bodies relating to environmental health effects and
human susceptibility that have occurred since 1990, which the commenter
states make the current EPA policy outdated. The commenter asserted
that the EPA acceptability benchmark policy needs to be reformed in the
face of increasing evidence that challenges the assumption of a safe or
acceptable level of HAP exposure.
---------------------------------------------------------------------------

    \7\ Survey of Risks, Benzene Rule Legacy Docket ID No. OAQPS 79-
3, Part I, Docket Item X-B-1 (cited at National Emission Standards
for Hazardous Air Pollutants; Benzene Emissions from Maleic
Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene Storage
Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery
Plants, 53 FR 28496, 28512/3-13/3 (July 28, 1988)).
---------------------------------------------------------------------------

    Response: The EPA considers this comment outside the scope of the
risk review for the Site Remediation source category. As the commenter
notes, this level of acceptable risk was determined based on the EPA's
prior analysis of general perception of relative risk (see Benzene
NESHAP, 54 FR 38046). The task of re-determining the public's general
concern for the level of acceptable risk falls outside the scope of an
individual risk review.
    However, our discussion in the proposal preamble addresses the
commenter's concern (See 84 FR 46143; September 3, 2019)--though
providing this explanation is not intended to reopen our approach. The
scope of the EPA's risk analysis is consistent with the EPA's response
to comments on our policy under the Benzene NESHAP, where the EPA
explained that ``[t]he policy chosen by the Administrator permits
consideration of multiple measures of health risk. Not only can the MIR
[maximum individual risk] figure be considered, but also incidence, the
presence of noncancer health effects, and the uncertainties of the risk
estimates. In this way, the effect on the most exposed individuals can
be reviewed as well as the impact on the

general public. These factors can then be weighed in each individual
case. This approach complies with the Vinyl Chloride mandate that the
Administrator ascertain an acceptable level of risk to the public by
employing his expertise to assess available data. It also complies with
the Congressional intent behind the CAA, which did not exclude the use
of any particular measure of public health risk from the EPA's
consideration with respect to CAA section 112 regulations, and thereby
implicitly permits consideration of any and all measures of health risk
which the Administrator, in his judgment, believes are appropriate to
determining what will `protect the public health.' '' (54 FR at 38057;
September 14, 1989.)
    The EPA subsequently adopted this approach in its residual risk
determinations and the Court upheld the EPA's interpretation that CAA
section 112(f)(2) incorporates the approach established in the Benzene
NESHAP. See NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008).
    Comment: One commenter claimed that the EPA did not assess whether
the health risk and emissions reductions of the rule provide an ample
margin of safety. The commenter stated that the EPA only considered the
cost and feasibility of available control measures from its technology
review, did not consider facility-wide risks, and ignored exempt
sources in its ample margin of safety decision. The commenter cited the
Court decision, Sierra Club v. EPA, 895 F.3d 1 (D.C. Cir. 2018) to
support their comment. Additionally, the commenter said the EPA did not
provide the underlying data it used to reach its facility-wide risk
determinations.
    Response: The EPA disagrees with the comment. The risk assessment
demonstrated that health risks due to air emissions from site
remediation sources are acceptable and after considering available
control options and all available risk information, the EPA concluded
that the current standards provide an ample margin of safety to protect
public health. The commenter misconstrues the analysis at pages 46157-
58 of the proposal. The EPA had already made a determination,
consistent with the methodology of the Benzene NESHAP, that the risk
posed by emissions from the affected sources in the Site Remediation
source category is acceptable. See 84 FR 46157 (September 3, 2019),
section C.1 ``risk acceptability.'' The EPA proceeds to look at
potential measures that could further reduce risk in the ample margin
of safety determination, and in that context, has consistently
historically considered multiple factors, including control technology
cost, cost effectiveness, feasibility, and the magnitude of risk and
potential risk reduction, as well as uncertainties. See NRDC v. EPA,
529 F.3d 1077, 1080-83 (D.C. Cir. 2008) (upholding as reasonable the
EPA's interpretation that CAA section 112(f)(2)(A) does not mandate
establishing emission standards to reduce cancer risks below 1-in-1
million and recognizing that CAA section 112(f)(2) incorporates the
EPA's approach in the Benzene NESHAP).
    The Court decision cited by the commenter,\8\ Sierra Club v. EPA,
895 F.3d 1 (D.C. Cir. 2018), addressed the basis for setting a health-
based emission limit based on a health threshold in lieu of a
technology-based standard for hydrochloric acid (HCl) under section
112(d)(4) of the CAA, not making a determination under section
112(f)(2) of the CAA.
---------------------------------------------------------------------------

    \8\ See the comment letter in Docket ID Item No.EPA-HQ-2018-
0833-0069, p 45.
---------------------------------------------------------------------------

    The EPA did not contemplate an ample margin of safety analysis for
RCRA/CERCLA-exempt sources because they are not subject to the
emissions standards in the rule. The ample margin of safety portion of
a CAA section 112(f) analysis necessarily entails an evaluation of
control options. For the EPA to undertake an ample margin of safety
analysis for the exempt sources, a final determination would first be
needed to eliminate the exemption and evaluate control options. We have
not yet concluded how these sources should be regulated under the Site
Remediation NESHAP. While we requested comment on issues related to
eliminating the exemption, we are not acting on the exemption in this
RTR process. As noted in our separate request for comment on the exempt
status of such facilities in the RTR proposal, the EPA continues to
analyze the effect of removing the exemption in terms of designing
appropriate regulatory provisions should the exemption be removed.
    The EPA considered facility-wide risks and determined that Site
Remediation emissions are not driving those risks. The risk at two
facilities where facility-wide risk was greater than 100-in-1 million
was driven by EtO, which, as explained at proposal, to the EPA's
knowledge, is not emitted from Site Remediation activities. Also, as
noted in the proposal, the EPA is separately addressing EtO emissions
in response to the results of the latest National Air Toxics Assessment
released in August 2018, which identified the chemical as a potential
concern in several areas across the country.
    The EPA disagrees that we did not provide the data for our whole-
facility analysis. The data files were placed in the docket for public
review upon publication (see Docket ID Item No. EPA-HQ-OAR-2018-0833-
0037).
4. What is the rationale for our final approach and final decisions for
the risk review?
    As explained in our proposal, the EPA sets standards under CAA
section 112(f)(2) using ``a two-step standard setting approach, with an
analytical first step to determine an `acceptable risk' that considers
all health information, including risk estimation uncertainty, and
includes a presumptive limit on MIR of approximately 1-in-10 thousand''
(see 54 FR 38045; September 14, 1989). We weigh all health risk
measures and factors in our risk acceptability determination, including
the cancer MIR, cancer incidence, the maximum noncancer TOSHI, the
maximum acute noncancer HQ, the extent and distribution of cancer and
noncancer risks in the exposed population, and the risk estimation
uncertainties.
    In the second step of the approach, the EPA considers whether the
emissions standards provide an ample margin of safety to protect public
health ``in consideration of all health information, including the
number of persons at risk levels higher than approximately 1-in-1
million, as well as other relevant factors, including costs and
economic impacts, technological feasibility, and other factors relevant
to each particular decision.'' \9\ The EPA must promulgate emission
standards necessary to provide an ample margin of safety to protect
public health or determine that the standards being reviewed provide an
ample margin of safety without any revisions. After conducting the
ample margin of safety analysis, we consider whether a more stringent
standard is necessary to prevent, taking into consideration costs,
energy, safety, and other relevant factors, an adverse environmental
effect.
---------------------------------------------------------------------------

    \9\ 54 FR 38045, September 14, 1989.
---------------------------------------------------------------------------

    Since proposal, neither the risk assessment nor our determinations
regarding risk acceptability, ample margin of safety, or adverse
environmental effects have changed. For the reasons explained in the
proposed rule, we determined that the risks from the Site Remediation
source category are acceptable, and the current standards provide an
ample margin of safety to

protect public health and prevent an adverse environmental effect.
Therefore, we are not revising 40 CFR part 63, subpart GGGGG to require
additional controls pursuant to CAA section 112(f)(2) based on the
residual risk review, and we are readopting the existing standards
under CAA section 112(f)(2).\10\
---------------------------------------------------------------------------

    \10\ The Court upheld this approach to CAA section 112(f)(2) in
NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008): ``If EPA
determines that the existing technology-based standards provide an
'ample margin of safety,' then the Agency is free to readopt those
standards during the residual risk rulemaking.''
---------------------------------------------------------------------------

B. Technology Review for the Site Remediation Source Category

1. What did we propose pursuant to CAA section 112(d)(6) for the Site
Remediation source category?
    Pursuant to CAA section 112(d)(6), we conducted a technology
review, which focused on identifying and evaluating developments in
practices, processes, and control technologies for the emission sources
in the Site Remediation source category. At proposal, we identified
developments in practices, processes, or control technologies for
process vents and equipment leaks.
    For process vents, one potential control technology was identified
at proposal, use of a regenerative thermal oxidizer, which could
increase the emissions capture and control efficiency from 95 percent
to 98 percent for those process vents that are currently controlled
with a carbon adsorption system or other device achieving 95-percent
control. We estimated the HAP emissions reduction beyond the current
control requirements could range between 0.09 and 0.18 tpy for the
source category, and the estimated costs would be $1 million to $2
million per ton of HAP emission reduction.
    For equipment leaks, we identified the more stringent leak
definitions of 40 CFR part 63, subpart UU over those of 40 CFR part 63,
subpart TT as a development in practices, processes, or control
technologies at proposal. Two options were identified: Option 1--
requiring the use of the leak detection thresholds of 40 CFR part 63,
subpart UU, for valves and pumps; Option 2--requiring the use of the
leak detection thresholds of 40 CFR part 63, subpart UU for valves and
pumps and also requiring connector monitoring under 40 CFR part 63,
subpart UU. For Option 1, we estimated an additional HAP emission
reduction of up to 4.7 tpy and estimated the costs would be $2,000 per
ton of HAP emission reduction. For Option 2, we estimated the HAP
emission reduction incremental to Option 1 would be approximately 5 tpy
and the incremental cost effectiveness between Option 1 and Option 2
would be $35,000 per ton of HAP emission reduction.
    Based on the costs and the emission reductions that would be
achieved with the identified developments, we proposed to revise the
MACT standard pursuant to CAA section 112(d)(6) to require facilities
to use the leak detection thresholds of 40 CFR part 63, subpart UU, for
valves and pumps, without the subpart UU requirements for connectors in
gas/vapor service and in light liquid service. We proposed that it was
not necessary to revise the MACT standards pursuant to CAA section
112(d)(6) to require 98-percent control for process vents, based on the
use of a regenerative thermal oxidizer. More information concerning our
technology review can be found in the memorandum titled CAA section
112(d)(6) Technology Review for the Site Remediation Source Category,
which is available in the docket for this action and in the preamble to
the proposed rule (84 FR 46160 and 46161; September 3, 2019).
2. How did the technology review change for the Site Remediation source
category?
    The technology review has not changed from proposal to this final
action. As explained below, the comments received were generally
supportive of the revisions to the equipment leak requirements to
require the use of the leak detection thresholds of 40 CFR part 63,
subpart UU, for valves and pumps, to not require connector monitoring
for equipment leaks, and to not require changes to the NESHAP for
process vents.
3. What key comments did we receive on the technology review, and what
are our responses?
    Most of the commenters on the proposed technology review supported
our proposed revised standards for equipment leaks and our
determination that revised standards for process vents are not
necessary for the Site Remediation NESHAP. One commenter requested that
we consider additional elements in our technology review, including
incorporating exempt sources in our analysis of the cost effectiveness
of connector monitoring, considering leakless equipment in our review
of the equipment leak standards, and considering a different threshold
for cost effectiveness. A complete summary of these and other comments
and responses are in the comment summary and response document,
available in the docket for this action (Docket ID No. EPA-HQ-OAR-2018-
0833). The following is a summary of key comments we received regarding
the technology review and our responses to those comments.
    Comment: One commenter asserted that the EPA must evaluate
developments in practices, processes, and control technologies to
reduce inorganic HAP and HAP metal emissions and must revise its
existing standards by setting limits that reflect the use of these
practices, processes, and control technologies. As emissions standards
in the Site Remediation NESHAP currently do not apply to these HAP, the
commenter noted that the EPA did not include these HAP in its
technology review. The commenter stated that the EPA must set emission
standards for each HAP that a source category emits and then must also
determine whether developments in pollution control make it
``necessary'' to revise the emission standards.
    Response: We acknowledge that the Site Remediation NESHAP does not
contain emissions standards for metal HAP and inorganic HAP. However,
the EPA's duty under CAA section 112(d)(6) is to review the standards
promulgated under CAA section 112(d)(2) and to evaluate any
developments in practices, processes, and control technologies to
determine whether it is necessary to revise the existing standards.
    The EPA's decision to consider regulation of these pollutants in
this rulemaking is not governed by or mandated by CAA section
112(d)(6). That provision requires the EPA to review and revise, as
necessary (taking into account developments in practices, processes,
and control technologies), emission standards promulgated under this
section. We do not agree with the commenter's assertion that the EPA
must establish new standards for unregulated emission points or
pollutants as part of a technology review of the existing standards.
The EPA reads CAA section 112(d)(6) as a limited provision requiring
the Agency to, at least every 8 years, review the emission standards
already promulgated in the NESHAP and to revise those standards as
necessary, taking into account developments in practices, processes,
and control technologies. Nothing in CAA section 112(d)(6) directs the
Agency to develop new emission standards to address HAP or emission
points for which standards were not previously promulgated as part of
or in conjunction with the mandatory 8-year technology review.

    When the EPA establishes standards for previously unregulated
emissions, we would establish the standards under one of the provisions
that govern initial standard setting--CAA sections 112(d)(2) and (3)
or, if the prerequisites are met, CAA section 112(d)(4) or CAA section
112(h). Establishing emissions standards under these provisions of the
CAA involves a different analytical approach from reviewing emissions
standards under CAA section 112(d)(6).
    While we did not consider establishing standards for these HAP
under CAA section 112(d)(6), we did investigate these HAP to determine
whether standards should be established under CAA section 112(d)(2) or
(3). In our review of the data for affected sources, we found that
metal HAP are not emitted. Therefore, standards are not required for
these pollutants (see 84 FR 46161; September 3, 2019) and our
discussion of this issue in section D.1.a of this document.) This
analysis satisfies the investigation into these pollutants that the EPA
said it intended to undertake for these HAP in response to Sierra
Club's petition for reconsideration of the initial NESHAP
rulemaking.\11\ For inorganic HAP, based on the EPA's analysis of the
available emissions data for affected sources, only one Site
Remediation operation emitted any inorganic HAP. The one inorganic HAP
emitted by this Site Remediation is asbestos, and asbestos emissions
are already regulated by another NESHAP (as discussed in more detail
below). Therefore, we determined it was not necessary to evaluate these
emissions further or to establish standards under CAA sections
112(d)(2) or (3) for these emissions.
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    \11\ See Letter from Janet McCabe to James Pew (March 25, 2015)
(Docket ID Item No. EPA-HQ-OAR-2018-0833-0012) (granting
reconsideration of 68 FR 58172 (October 8, 2003)).
---------------------------------------------------------------------------

    Comment: One commenter stated that the EPA should do more than it
proposed for regulating equipment leaks because there have been
additional developments in equipment, such as leakless or low-emission
valves and zero-emissions technologies, and the commenter asserts that
these technologies should be required. The commenter also remarked that
the EPA's rationale for not requiring connector monitoring is flawed,
in that it did not account for emissions reductions from the facilities
exempt from the rule under the RCRA/CERCLA exemption. The commenter
opined that since these facilities have not had to comply with the
existing Site Remediation standards, it is likely there would be
greater emissions reductions from these facilities, which would result
in an improvement in the cost effectiveness of the measure. The
commenter also mentioned that considering cost on a per ton basis for
all emitted HAP does not make sense when the pollutants have vastly
varying toxicities. The commenter further stated that the EPA does not
explain why it believes an incremental cost of $35,000 per ton of HAP
reduced is an unreasonable cost.
    Response: First, we disagree that leakless valves and low-emissions
technologies should have been included in the technology review. These
and similar types of equipment were available and accounted for when
the original NESHAP was promulgated, and, therefore, they are not
``developments'' in technology.\12\ The commenter has not identified
``developments'' in relation to this technology, such as a significant
decrease in cost or a change in applicability to the Site Remediation
source category. Next, in determining the impacts from any control
options, we include only the emissions and reductions that would
actually be expected to occur as a result of the implementation of that
control option. In this case, since some facilities are exempt from
emissions control requirements, the impacts are based on the emissions
reductions and costs of implementation at the facilities that would be
required to comply with the regulations. If the currently exempt
facilities become subject to emissions control requirements in the
future, we will reassess the impacts of potential control options at
that time.
---------------------------------------------------------------------------

    \12\ U.S. EPA. National Emission Standards for Hazardous Air
Pollutants (NESHAP) for Site Remediation (40 CFR part 63, subpart
GGGGG)--Background Information for Promulgated Standards. Office of
Air Quality Planning and Standards. Research Triangle Park, NC.
August 2003. pp. 44-45.
---------------------------------------------------------------------------

    The EPA disagrees that, for this action, an analysis that relies on
a cost-per-ton basis ``does not make sense'' when different HAP have
different toxicities. We note that when assessing the cost
effectiveness of more stringent standards under consideration, we have
discretion to express emission reductions that would result from such
standards in any reasonable format, such as costs per ton of emissions
reduced. In this case, as explained at proposal, the risk for the Site
Remediation source category was low, using both the quantity and
toxicity of emitted pollutants to arrive at this conclusion. The EPA
also adds that a cost-per-ton basis may not be the only economic
consideration when deliberating on whether to adopt controls. The EPA
also looks, where appropriate, at the broader economic impact a given
control technique may have on the category of sources when deciding
whether to adopt a given standard.
    With respect to the role of cost in our decisions under the
technology review, we note that courts have not required the EPA to
demonstrate that a technology is ``cost-prohibitive'' in order not to
require adopting a new technology under CAA section 112(d)(6); a simple
finding that a control is not cost effective is enough. See Association
of Battery Recyclers, et al. v. EPA, et al., 716 F.3d 667, 673-74 (DC
Cir. 2015) (approving the EPA's consideration of cost as a factor in
its section 7412(d)(6) decision-making and EPA's reliance on cost
effectiveness as a factor in its standard-setting). The EPA declined to
include connectors in our decision to lower the definition of the leak
threshold, based on the fact that, relative to a limited impact on
emissions, the addition of connectors would have increased the cost of
the LDAR program by more than an order of magnitude from the option
chosen (i.e., lower leak thresholds for pumps and valves).
4. What is the rationale for our final approach for the technology
review?
    Based on our analysis for equipment leaks, we have determined the
costs of Option 1 are reasonable, given the level of HAP emissions
reduction that would be achieved with this control option. We do not
believe the costs of Option 2 are reasonable, given the level of HAP
emissions reduction Option 2 would achieve relative to a much higher
incremental cost- per-ton above Option 1. Therefore, as a result of the
technology review, pursuant to CAA section 112(d)(6), we are finalizing
our proposed determination to revise the Site Remediation NESHAP to
require existing and new affected sources to comply with the 40 CFR
part 63, subpart UU leak detection thresholds for pumps and valves
rather than leak thresholds of 40 CFR part 63, subpart TT, for those
components.
    For the reasons discussed above and in the preamble to the proposed
rule, we have determined that it is not necessary, pursuant to CAA
section 112(d)(6), to revise the Site Remediation NESHAP to require
additional HAP emission controls for process vents or any other
equipment or processes at Site Remediation facilities.

C. CAA Sections 112(d)(2) and (3) Amendments

1. What did we propose pursuant to CAA sections 112(d)(2) and (3) for
the Site Remediation source category?
    We proposed to add a work practice standard pursuant to CAA section
112(h)(2)(B), in conjunction with CAA sections 112(d)(2) and (3), for
PRDs. PRDs are valves, rupture disks, or other equipment designed to
remain closed during normal operation but that ``actuate'' (e.g., the
valve seat opens or a rupture disk ruptures) in the event of an
overpressure in the system caused by operator error, a malfunction such
as a power failure or equipment failure, or other unexpected cause that
results in immediate venting of gas from process equipment in order to
avoid safety hazards or equipment damage. The current Site Remediation
NESHAP follows the EPA's previous practice of exempting SSM events from
otherwise applicable emission standards. Consequently, with emissions
releases from a PRD release actuation event treated as a type of
malfunction, the Site Remediation NESHAP did not restrict emissions
releases to the atmosphere from a PRD actuation event (i.e., PRD
releases were exempt from the otherwise applicable emission standards).
In Sierra Club v. EPA, 551 F.3d 1019 (DC Cir. 2008), the Court
determined SSM exemptions in CAA section 112 standards violate the CAA.
    To ensure a standard continuously applies during malfunctions that
result in emissions from a PRD actuation event, we proposed work
practices and other provisions for PRDs and bypass lines on closed vent
systems. We explained that a work practice standard is warranted under
CAA section 112(h) because the application of measurement technology to
this class of sources is not practicable due to technological and
economic limitations. See 84 FR 46153 (September 3, 2019). Modeling the
work practice standard on the Petroleum Refinery Sector RTR (80 FR
75178; December 1, 2015), we proposed to add work practice requirements
that consist of conducting an analysis of the cause of a PRD actuation
event and the implementation of corrective measures for PRDs that emit
directly to the atmosphere. In addition, we proposed criteria for what
constitutes a deviation from the work practice requirements. For PRDs
that vent emissions from actuation events directly to the atmosphere,
we proposed it would be a deviation of the work practice standard for a
single PRD to have two releases within a 3-year period due to the same
cause; for a single PRD to have three releases within a 3-year period
for any reason; and for any PRD to have a release for which the cause
was determined to be operator error or poor maintenance. We also
proposed that ``force majeure'' events, which we proposed to define as
events resulting from natural disasters, acts of war or terrorism, or
external power curtailment beyond the facility's control (as
demonstrated to the satisfaction of the EPA Administrator), would not
be included when counting the number of releases. We proposed that
certain PRDs would not be subject to the work practice requirements due
to their low potential to emit substantial quantities of HAP. These
PRDs included the following: (1) PRDs designed and operated to route
all pressure releases through a closed vent system to a drain system,
fuel gas system, process or control device; (2) PRDs in heavy liquid
service; (3) PRDs that are designed solely to release due to liquid
thermal expansion; and (4) pilot-operated and balanced bellows PRDs if
the primary release valve associated with the PRD is vented through a
control system.
    To ensure compliance with these provisions, we also proposed that
facilities subject to the Site Remediation NESHAP monitor PRDs in
remediation material service that release to the atmosphere by using a
device or system that is capable of identifying and recording the time
and duration of each actuation event and notifying operators
immediately that a pressure release is occurring. We further proposed
to require owners or operators to keep records and report any actuation
event and the amount of HAP released to the atmosphere with the next
periodic report. In addition, to add clarity to these provisions, we
proposed to add definitions for ``bypass,'' ``force majeure event,''
``pressure release,'' and ``pressure relief device or valve'' to 40 CFR
part 63, subpart GGGGG. We also proposed to remove the definition of
``safety device'' and the provisions related to safety devices from 40
CFR part 63, subpart GGGGG, which would overlap with and be redundant
of parts of the proposed definition of ``pressure relief device or
valve'' and the provisions related to these devices.
    For purposes of estimating the costs of the proposed requirement to
monitor HAP releases to the atmosphere from PRDs, we assumed that
operators would already have monitoring systems capable of identifying
and recording the time and duration of each pressure release.
    In the proposed rule, we removed the exemption from emissions
standards for periods of SSM in accordance with a decision of the
Court, Sierra Club v. EPA, 551 F.3d 1019 (DC Cir. 2008), cert. denied,
130 S. Ct. 1735 (U.S. 2010). This decision stated that the EPA must
provide standards that are in place at all times, even during periods
of SSM. The EPA has interpreted this to include provisions exempting
sources from otherwise applicable standards during maintenance periods.
Thus, we also proposed to remove the provision at 40 CFR 63.7925(b)(1)
that allowed a control device to be bypassed for up to 240 hours per
year for the performance of planned routine maintenance of the closed
vent system or control device (i.e., 240-hour routine maintenance
exemption). As a result, the emissions limits, including those for
tanks, in the proposed revised Site Remediation NESHAP would apply at
all times.
2. How did the proposed amendments pursuant to CAA sections 112(d)(2)
and (3) change for the Site Remediation source category?
    We have made two revisions to the proposed work practice and
associated monitoring requirements and also revised the estimate of
costs associated with PRD monitoring. The revisions to the proposed
work practice and monitoring requirements include adding PRDs to the
list of Site Remediation equipment in 40 CFR 63.7882 to help clarify
when a PRD is subject to equipment leak requirements and when it is
subject to the PRD actuation event work practice requirements. We are
also revising the proposed PRD provisions to exclude PRDs on
``containers'' (as defined at 40 CFR 63.7957) from the PRD work
practice standards and monitoring requirements. Additionally, we have
revised the economic analysis for the adoption of the proposed PRD
monitoring requirements to reflect the purchase of monitoring equipment
for some facilities rather than assuming all facilities already have
adequate monitoring systems.
3. What key comments did we receive on the proposed amendments pursuant
to CAA sections 112(d)(2) and (3), and what are our responses?
    Comment: Several commenters recommended that the EPA amend 40 CFR
63.7923(d) to include an exemption for PRDs on mobile equipment,
similar to the exemption in the Petroleum Refineries NESHAP in 40 CFR
63.648(j)(5)(vi). One of these commenters extended this recommendation
to portable containers, similar to the exemption in the Off-Site Waste
and Recovery Operations (OSWRO) NESHAP. This commenter is concerned
that the EPA has not

evaluated the HAP emissions that may be associated with PRDs on
portable equipment, noting that containers are generally already
subject to separate MACT requirements which would address their
emissions. The commenter also remarked that since facilities generally
do not own tank trucks and other transport vehicles, and they are not
dedicated to the facility, it would be impractical and overly broad to
impose monitoring requirements on them. Further, the commenter is
concerned that potential monitoring requirements would be technically
infeasible to implement on containers due to the wide range of
containers and their transitory nature. Specifically, the commenter
noted that containers can vary drastically in size from site to site
and cover a variety of cylinders, drums, tote-tanks, cargo tanks,
isotainers, railcars, over-the-road tanker vehicles, etc. The commenter
also remarked that the time they are kept on site depends highly on
facility-specific operational activities and can range anywhere from a
few days to a few weeks or months. Combined, the commenter said these
factors make it incredibly difficult, if not impossible, to
appropriately design and effectively implement a continuous monitoring
system for each container's PRD.
    One commenter also recommended that the EPA include an exemption
for PRDs that do not have the potential to emit 72 pounds (lbs)/day or
more of volatile organic compounds (VOC) based on the valve diameter,
the set release pressure, and the equipment contents, similar to the
exemption in the Petroleum Refineries NESHAP in 40 CFR 63.648(j)(5)(v).
The commenter stated that the EPA's logic for that exemption, which is
that it was consistent with the treatment of miscellaneous process
vents and consistent with the two California rules (Bay Area and South
Coast) that served as the MACT floor for the Petroleum Refineries
NESHAP, also applies to this rule.
    Response: The EPA agrees that an exception would be appropriate for
moveable equipment, such as trucks with containers, or tanks, train
cars, and similar moveable equipment that may be brought to a Site
Remediation for short durations. The EPA agrees that such equipment may
not be under the control of the affected facility and/or that altering
such equipment to meet the monitoring requirements for PRDs is
impractical. The EPA has, therefore, added an exception for
``containers,'' as that term is defined at 40 CFR 63.7957, which
encompasses movable equipment such as trucks, train cars, or barges.
The EPA has followed the model of the OSWRO NESHAP in this regard. See
83 FR 3986 (January 29, 2018).
    The EPA disagrees that it is appropriate to exempt PRDs that do not
have the potential to emit 72 lbs./day or more of VOC based on the
valve diameter from the PRD work practice. The commenter suggests the
provisions should be adopted because the exemption is also found in the
Petroleum Refineries NESHAP in 40 CFR 63.648(j)(5)(v). The exemption to
which the commenter refers is refinery-specific and applies to ``Group
1 process vents,'' as defined in the Petroleum Refineries NESHAP.\13\
The commenter did not provide information as to why an exemption for
Refinery Group 1 process vents should be applied to remediation
material management units (RMMUs). RMMUs are subject to Site
Remediation NESHAP standards according to the criteria in 40 CFR
63.7881(c)(1), 40 CFR 63.7882(a)(2) and 40 CFR 63.7886(d). The
differences in these emission points is reflected in the definition of
the Refinery Group 1 process vent in contrast to the applicability
criteria for RMMUs. The EPA does not find these two sets of units
sufficiently similar to warrant applying this provision to RMMUs, given
the wide variety of RMMUs that may be found subject to the Site
Remediation NESHAP. The commenter also provided no context as to why 72
lbs./day is appropriate, given the different emission potential that
determines affected facility status of the units on which the PRDs are
found in Site Remediation. The 72 lbs./day provision for Petroleum
Refineries NESHAP was set based on CAA section 112(d)(2) (i.e., a MACT
floor for petroleum refineries). The EPA does not have, and the
commenter did not provide, data to support either a 72 lbs./day
exemption or other value to apply as an exemption threshold for the
Site Remediation source category. However, certain applicability
criteria that the EPA finds appropriate to apply in the context of PRD
activations in the site remediation context are identified at 40 CFR
63.7923(d).
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    \13\ Group 1 miscellaneous process vent means a miscellaneous
process vent for which the total organic HAP concentration is
greater than or equal to 20 parts per million by volume, and the
total VOC emissions are greater than or equal to 33 kilograms per
day for existing sources and 6.8 kilograms per day for new sources
at the outlet of the final recovery device (if any) and prior to any
control device and prior to discharge to the atmosphere.
---------------------------------------------------------------------------

    Comment: One commenter expressed opposition to what the commenter
referred to as ``three exemptions'' included in the proposed work
practice standards for PRDs, asserting that the work practice standards
must apply at all times. According to the commenter, a provision that
allows sources to exceed the emissions standards two or three times
every 3 years essentially allows non-continuous compliance with the
CAA, which is inconsistent with the Court precedent. Regarding force
majeure events, the commenter stated that this provision is an
exemption that simply provides new semantics for the rejected
malfunction exemption and is equally unlawful. The commenter further
explains that the concept of force majeure is from contracts law and
does not fit with compliance with federal law. The commenter asserts
that injecting contractual principles or negotiating regulations with a
regulated party runs directly counter to the statutory test in which
compliance is non-negotiable. According to the commenter, the EPA does
not have the discretion to promulgate an exemption that allows EPA to
decide what is a violation, or not, at a future time, as the Court has
the authority to decide whether a violation has occurred warranting a
penalty. This exemption, the commenter claims, places the burden on the
government or citizen enforcer to prove both that excess emissions have
occurred and that they did not occur during a force majeure event. The
commenter also states that the exemption for PRDs with low potential to
emit is unlawful because the CAA directs the EPA to establish limits
that apply on a continuous basis for each HAP a source emits,
regardless of the amount emitted. The commenter adds that it should be
easy for PRDs to comply with the limits if they truly have low
emissions.
    Response: The EPA disagrees with the commenter that the proposed
work practice is not a standard applicable to the affected source at
all times. Under CAA section 112(h), work practices are a form of
emissions standard applicable to affected units. Actuation events from
PRDs that vent to the atmosphere are irregular in time, duration,
amount, cause, and effect. Attempts to capture such emissions may be
potentially dangerous to workers, the public, and the environment. The
EPA's work practice standards require a series of preventive measures
\14\ and the use of diagnostic tools to prevent recurrence of such
events, coupled with a clearly defined basis for enforcement action
when there is a failure to prevent actuation event recurrence under the

defined circumstances. This work practice standard represents the
practice employed by the best performing sources and is the MACT floor.
The MACT floor is not merely after-the-fact recordkeeping requirements
to document PRD actuation events without penalty. The PRDs at affected
facilities are subject to continuous monitoring, and, in addition to
other potential bases for finding a violation as described in 40 CFR
63.7923(f), each PRD actuation is a violation if the cause is poor
maintenance or operator error.
---------------------------------------------------------------------------

    \14\ See 84 FR 46153 (September 3, 2019) for a discussion of
requirements under 40 CFR part 68, Chemical Accident Prevention
Provisions for PRDs.
---------------------------------------------------------------------------

    The EPA disagrees with the comments regarding force majeure events.
Force majeure events, which result in pressure release actuation
events, must be accounted for under 40 CFR 63.7923(c). The definition
of force majeure narrows the scope of such events to natural disasters;
acts of war or terrorism; loss of a utility external to the Site
Remediation unit (e.g., external power curtailment), excluding power
curtailment due to an interruptible service agreement; and fire or
explosion originating at a near or adjoining facility outside of the
Site Remediation affected source that impacts the Site Remediation
affected source's ability to operate. Therefore, a force majeure event
would never be due to operator error or poor maintenance (see 40 CFR
63.7923(f)(1)) and must be absolutely beyond the power or ability of
the source to prevent. We believe that the narrow scope of force
majeure is such that a second event, from a single pressure relief
device in a 3-year period would be highly unlikely to be due to the
same force majeure event for the same equipment. (See 40 CFR
63.7923(f)(2)). Similarly, we believe that it is highly unlikely that
in a 3-year period, three force majeure events of any type would occur
for the same equipment. Finally, the source must satisfy the
Administrator that the event was beyond the control of the owner or
operator, because the decision to accept the claim of force majeure is
solely within the discretion of the Administrator. Thus, the force
majeure provisions are an intrinsic part of the work practice standard
and are not as the commenter maintains an exemption from that standard.
    The EPA disagrees with the comments regarding the exemption for
certain types of PRDs identified in 40 CFR 63.7923(e). We modeled the
applicability of the PRD provisions after the Petroleum Refinery rule,
40 CFR part 63, subpart CC. That ``beyond-the-floor'' analysis
determined that it was not cost effective to include control of these
PRDs as part of the work practice standard for PRDs, and we do not have
information to conclude that this analysis would be any different for
Site Remediation sources. However, these PRDs may be regulated under
other provisions of the MACT. We note that, if the PRD is on any
equipment subject to the equipment leaks requirements at 40 CFR
63.7920-7922, then the PRD is also subject to those same requirements,
and owners and operators are still required to monitor the PRD after
the release to verify the device is operating with an instrument
reading of less than 500 ppm. Such PRDs are subject to repair
requirements if a leak is found.
    Comment: Several commenters requested clarification that the PRDs
covered by the work practices are only those associated with the Site
Remediation equipment leaks affected sources (i.e., only PRDs that are
in service for 300 or more hours per year and that contain or contact
remediation material having a concentration of total HAP listed in
Table 1 equal to or greater than 10 percent by weight).
    Response: The EPA did not intend for the PRD actuation work
practice requirements to only apply to PRDs in contact with remediation
material with HAP content (for those HAPs listed in Table 1 to subpart
GGGGG) equal to or greater than 10 percent by weight and that are in
service for 300 hours per year or more. The PRD work practice also
applies to PRDs protecting any affected units subject to this subpart
(with the exception of containers), including RMMUs under 40 CFR
63.7882(a)(2). Thus, PRDs are subject to the PRD work practice if they
are protecting process vents, tanks, surface impoundments, separators,
transfer systems, or closed-vent systems and control devices--
regardless of whether such units meet the 40 CFR 63.7882(a)(3)
thresholds for equipment leak requirements. Note that PRDs are not
subject to the work practice standard if they are on containers as
defined at 40 CFR 63.7957, which are subject to the requirements of 40
CFR 63.7900-7903. The PRD standards must work in conjunction with the
emission limits for all such affected units to ensure that a standard
applies at all times, including during malfunction periods. The
exemption suggested by the commenter would leave PRD actuation events
from certain affected units subject to no standards during
malfunctions. Certain RMMUs (40 CFR 63.7886) may be exempt from control
requirements based on the criteria in 40 CFR 63.7886(d). A PRD
protecting equipment found to be exempt under 40 CFR 63.7886(d) would
likewise be exempt from PRD standards, because the unit the PRD is
protecting is not subject to control requirements.
    The commenter is correct that a PRD as a member of the set of
equipment subject to 40 CFR 63.7882(a)(3) would not be subject to LDAR
requirements for ``equipment leaks'' if the PRD ``at rest'' (meaning
not in actuation) meets either of the criteria in 40 CFR 63.7882(a)(3),
that is, either: (1) The HAP content of the remediation material is
less than 10 percent by weight; or (2) the equipment in question is
used less than 300 hours per year. The applicable requirements to
ensure a PRD has been repaired or re-sets properly after actuation are
found in 40 CFR 63.7923(a)(1) and (2). The corresponding recordkeeping
for such PRDs that are exempt from LDAR while at rest but subject to
PRD work practices in activation are found at 40 CFR 63.7950(b)(11).
    Comment: Several commenters remarked that the EPA should have
provided a burden estimate for certain requirements. One commenter
pointed out that the EPA did not include a burden estimate for
implementation and reporting for the new PRD work practice requirements
and submittal of the PRD Notice of Compliance Status. Several
commenters stated that the EPA has assumed that sources have a system
already in place that is capable of identifying and recording the time
and duration of each pressure release from a PRD and of notifying
operators that a pressure release is occurring, and remarked that
sources actually often do not have systems like this in place unless
they are required by regulation; therefore, there will be a cost to
implement this proposed requirement. One commenter noted that one
company has five PRDs that vent to the atmosphere potentially subject
to the proposed requirements, and that none of these currently have
monitors in place. The commenter also said that some facilities with
PRD monitors are not set up to communicate with the control room or are
not capable of determining the duration of a release. One commenter
estimated that the cost to install a new monitoring system will be
approximately $15,000 per PRD.
    One commenter expressed that the EPA has not included time for
facilities to develop procedures to estimate and report the amount of
excess emissions when a deviation from the new requirements of 40 CFR
63.7951(b) occurs or to develop procedures for the new deviation
recordkeeping requirements at 40 CFR 63.7952.
    Response: The EPA disagrees that it failed to provide an estimate
at proposal as to the cost and burdens associated with the work
practice standard. However, we have adjusted that estimate as discussed
below, and we

have appropriately estimated the costs and burdens associated with
implementation and reporting for the PRD work practice standard. At
proposal, we assumed that any facility subject to the proposed PRD
requirements would likely experience one PRD actuation event every 3
years, which would require an analysis of the event's cause. The EPA
estimated an additional cost to implement the analysis of PRD actuation
events for affected facilities that was reflected in the burden
estimate at proposal. Upon consideration of the comment regarding the
PRD Notification of Compliance Status, we have made a description of
the PRD monitoring system part of the semiannual compliance report. It
may have been unclear at proposal whether this one-time notification
would be part of the submittal of the next semiannual report, for which
we already have estimated a burden to complete. We have clarified that
this notification is submitted with the semiannual compliance report.
The description of the monitoring system must be updated in subsequent
reports only if changes are made. With respect to monitoring, the EPA
has revised our burden estimate to include the cost of additional
monitoring for sources that do not already have adequate monitoring for
PRDs. We have estimated that half of the affected facilities must
acquire between 1 and 5 monitors to meet the new requirement, at an
estimated annualized cost of $30,000 for the entire source category.
For more information regarding the revised PRD monitoring burden
estimate, see the memorandum, Pressure Relief Device Monitoring Impacts
for the Site Remediation Source Category, available in the docket for
this action.
    Regarding deviation recordkeeping and reporting, we are providing
additional time to develop emissions estimation and reporting
procedures. The compliance date for existing affected sources for the
revised SSM requirements other than General Provisions, 40 CFR 63.6(e)
and (f)(1), is 180 days after the effective date of the standard. The
requirements for electronic reporting requirements, the revised routine
maintenance provisions, the operating and pressure management
requirements for PRDs, and the revised requirements regarding bypasses
and closure devices on pressure tanks is 180 days after the effective
date of the standard.
4. What is the rationale for our final approach for the amendments
pursuant to CAA sections 112(d)(2) and (3)?
    To ensure a standard continuously applies during malfunctions that
result in emissions from a PRD actuation event, we proposed work
practices and other provisions for PRDs and bypass lines on closed vent
systems. Based on comments received on the proposed provisions, we have
revised the proposed work practice and associated monitoring
requirements for PRDs. For the reasons provided in the responses to
comments above, we have revised the proposed PRD provisions to exclude
PRDs on containers from the PRD work practice standards and monitoring
requirements and added language to 40 CFR 63.7882 to help clarify when
a PRD is subject to equipment leak requirements and when it is subject
to the PRD actuation event work practice requirements. Additionally,
based on information provided by commenters, we have revised the
economic analysis for the adoption of the proposed PRD monitoring
requirements to reflect the purchase of monitoring equipment for some
facilities rather than assuming all facilities already have adequate
monitoring systems.

D. Other Issues and Changes Made to the Site Remediation NESHAP

1. Standards for Inorganic and Metal HAP Emissions
a. What did we propose for inorganic and metal HAP emissions?
    In the May 13, 2016, proposal on reconsideration, the EPA stated
that it would consider the issue of regulating metals and inorganic HAP
emissions during the risk review (81 FR 29824). In the September 3,
2019, proposal, the EPA proposed to not set standards for metals and
inorganic HAP from Site Remediation sources subject to the Site
Remediation NESHAP because the Agency did not have data indicating that
site remediation sources subject to the rule emit these pollutants. The
EPA requested data demonstrating whether or not any affected Site
Remediation sources emit inorganic or metal HAP.
b. How did the decision regarding inorganic and metal HAP emissions
change since proposal?
    In this final action, we have not made any changes to the proposed
decision related to inorganic HAP and metal emissions standards.
c. What key comments did we receive regarding inorganic and metal HAP,
and what are our responses?
    Comment: One commenter observed that of over 200 Site Remediations
in the country, the EPA found data for only six facilities. The
commenter claimed that the EPA has nearly complete ignorance about
actual Site Remediation emissions due to a failure by the EPA to
collect the necessary data and asserts that claiming a lack of data
without adequate enquiry does not excuse the Agency from the
requirements of the CAA to set emission standards for each HAP a source
category emits. The commenter added that data for the source category,
including exempt facilities, clearly shows that Site Remediations do
emit specific and substantial quantities of inorganic and metal HAP,
citing EPA's residual risk assessments in the docket at proposal. In
contrast, several other commenters observed that the risk assessment
and the EPA's data for this source category do not demonstrate that
inorganic HAP and HAP metals are emitted from affected facilities and
agree with the EPA's decision not to set standards for these
pollutants. Two of these commenters also note that metals are the HAP
driving risks; however, this is an assumption of the model plant
approach employed in conducting the risk assessment. The commenters
stated that these HAP are likely not emitted, and the actual risks are
likely much lower than the EPA estimates.
    Response: The NEI is the basis for establishing emission profiles
for the Site Remediation source category and many EPA residual RTRs
performed or are in progress within the Agency. The NEI is a
comprehensive national database operated by the regulated community,
state agencies, and the EPA to have data available for research and
analysis, public information, and rulemaking. In the case of the Site
Remediation RTR, to perform the risk assessment, the EPA used data
submissions from approximately 220 facilities (102 affected facilities
and 118 exempt facilities) that submitted over 55,000 records of
pollutant emissions for over 4,000 emission units at the entire
facilities (i.e., not just units subject to the Site Remediation
NESHAP). The NEI provides the best information available to the EPA
regarding emissions from the Site Remediation source category.
    Of the affected sources, the EPA did not find any affected
facilities that reported Site Remediation emissions of metals and found
only one facility that emitted any other inorganic HAP, which

was asbestos. Upon further investigation of the asbestos emissions at
this facility, the EPA discovered that the Site Remediation at this
facility is subject to other rules applicable to asbestos cleanups,
including 40 CFR part 61, subpart M, the Asbestos NESHAP. The EPA has
determined that since the asbestos emissions are already regulated by
another NESHAP in this instance, it is not necessary to regulate those
emissions separately in the Site Remediation NESHAP.
    The EPA disagrees with the commenter's assertion that exempt
facilities emit substantial quantities of inorganic HAP and metals. The
emissions reported in the NEI for exempt facilities shows a total of
0.04 tpy of HAP metal emissions, all of which are from one facility,
and 1.3 tpy of other inorganic HAP emissions, with 97 percent of these
emissions from one facility. Thus, while some exempt facilities emit
limited quantities of metal and inorganic HAP, the nature of Site
Remediations, which are highly site-specific and vary widely in
remediation materials treated, treatment methods and equipment, and
emissions, does not suggest that emissions of metal and inorganic HAP
are common in Site Remediations, are emitted in large quantities, or
would be expected from affected facilities. Therefore, without further
evidence to support the existence of metal or inorganic HAP emission
from affected facilities, the EPA has determined it is not necessary to
develop emissions standards for these pollutants for this source
category.
    We agree with commenters that the risk assessment, which used a
model approach to attribute emissions to the Site Remediation portion
of a facility where the NEI did not include Site Remediation emissions,
likely overstates the emissions of some HAP from the Site Remediation
portions of the facilities. Where this is true, risk from those HAP
would be overstated in the risk assessment results.
    As we stated at proposal, to address the limited data on Site
Remediation emissions for these 96 facilities, the EPA developed a
model plant approach for its risk assessment. A model plant approach is
commonly used in other EPA actions. The EPA developed a profile of Site
Remediation emissions for each facility by applying an emissions factor
based on emissions from the entire facility, including its non-category
emissions from primary processes. Some of these non-category emission
sources emit metal and inorganic HAP, thus leading to an attribution of
a fraction of those emissions at a facility to the Site Remediation
category by virtue of the use of the emissions factor. Thus, the model
plant data used for modeling risk reflect metal and inorganic emissions
solely because they are emitted by non-category sources elsewhere in
the facility. The tables in Residual Risk Assessment for Facilities
Exempt from the Site Remediation Source Category in Support of the Risk
and Technology Review 2019 Proposed Rule (see Docket ID Item No. EPA-
HQ-OAR-2018-0833-0028, p. 37-43) cited by the commenter do not
specifically distinguish which compounds cited by the commenter are
facility-wide non-category emissions adapted to the model plant and
therefore not actual emissions from site remediation activity, from
those pollutants emitted by site remediation activity. With the
exception of HCl, the compounds cited by the commenter are facility-
wide non-category emissions, and not emitted by site remediation
activity. See section IV. A.3 of this preamble for our discussion on
HCl. The commenter's assertion that data for the source category shows
that site remediations emit specific and substantial quantities of
inorganic and metal HAP is not actually supported by the data cited by
the commenter.
d. What is the rationale for our final decision regarding inorganic and
metal HAP?
    For the reasons provided above and in the preamble for the proposed
rule, we are finalizing the proposed decision to not set standards for
metals and inorganic HAP from Site Remediation sources.
2. SSM
a. What did we propose for SSM?
    We proposed amendments to the Site Remediation NESHAP to remove or
revise provisions related to SSM that are not consistent with the
requirement that the standards apply at all times.
b. How did the amendments regarding SSM change since proposal?
    For SSM, the Site Remediation NESHAP at 40 CFR 63.7925(b)(1) allows
a facility to bypass control devices for up to 240 hours per year to
perform planned routine maintenance of the closed-vent system or
control device in situations when the routine maintenance cannot be
performed during periods that the control device is shut down. To
ensure that emissions standards apply at all times, we proposed to
revise 40 CFR 63.7925(b)(1) to require the control device to be
operating whenever gases or vapors containing HAP are vented through
the closed-vent system to the control device. Based on comments
received regarding these requirements, we have revised these proposed
requirements as they apply to storage tanks. The revised requirements
will allow a facility to bypass control devices on storage tanks for up
to 240 hours per year to perform planned routine maintenance of the
closed-vent system or control device in situations when the routine
maintenance cannot be performed during periods that the control device
is shut down, and they are restricted from filling the tank for those
240 hours. More information concerning SSM is in the preamble to the
proposed rule (84 FR 46161; September 3, 2019). We also are clarifying
the compliance dates for changes in the SSM provisions. See section
III.F of this preamble for compliance dates.
c. What key comments did we receive regarding SSM, and what are our
responses?
    We received several comments regarding SSM. We received one comment
that HAP concentrations may be higher in remediation material at the
startup of remediation activities, one comment that the removal of the
SSM exemption is not necessary to be consistent with the Sierra Club
vs. EPA decision, and one comment generally supporting the proposed SSM
revisions. One commenter generally supported the revisions but opposed
what they characterized as ``exemptions'' provided for PRDs during
process malfunctions. Other commenters disagreed with the proposed
changes related to periods of planned routine maintenance in 40 CFR
63.7925(b)(1) as they would affect tanks. Our responses to these
comments can be found in the Response to Comments document in the
docket. In addition to comments on SSM, we also received comment on the
topic of periods for planned routine maintenance. A summary of these
comments and our response is below.
    Comment: Several commenters requested that the EPA retain an
allowance for maintenance of control devices for tanks and add the work
practice to the Site Remediation NESHAP that was finalized in the Amino
and Phenolic Resins (APR) NESHAP RTR Reconsideration in October 2018.
The commenters explained that this work practice allows closed vent
systems on tanks to be bypassed for up to 240 hours per year for
routine maintenance but prohibits sources from increasing the level of
material in the tank during that time to minimize emissions by ensuring
no working losses occur. Another commenter requested that the EPA

retain the current routine maintenance provision that allows all
closed-vent system or control devices to be bypassed for up to 240
hours per year to perform routine maintenance. This commenter stated
that the EPA has not provided any justification or analysis of the
costs or emissions impact associated with the proposed change.
    Response: In the proposed rule, we removed the exemption from
emissions standards for periods of SSM in accordance with a decision of
the Court, Sierra Club v. EPA, 551 F.3d 1019 (DC Cir. 2008), cert.
denied, 130 S. Ct. 1735 (U.S. 2010). This decision stated that the EPA
must provide standards that are in place at all times, even during
periods of SSM. Thus, we also removed the provision at 40 CFR
63.7925(b)(1) that allowed a control device to be bypassed for up to
240 hours per year for the performance of planned routine maintenance
of the closed vent system or control device (i.e., 240-hour routine
maintenance exemption). As a result, the emissions limits, including
those for tanks, in the proposed revised Site Remediation NESHAP would
apply at all times.
    While emissions from most equipment can be eliminated completely
during routine maintenance of a control device, simply by not operating
the process during those times, the same is not true for a tank. For a
fixed roof tank complying with the NESHAP by routing emissions through
a closed vent system to a control device, the stored material in the
tank will continue to emit volatile compounds when the control device
is not operating. The only ways for these tanks to avoid such emissions
are to empty and degas the tank prior to the maintenance activity. It
is possible that emptying and degassing a tank could result in greater
emissions than would result from emissions from the tank during a 240-
hour period. At proposal, we did not consider this emissions potential.
Taking this factor into account, we decided to examine whether separate
MACT standards should be established for periods of planned routine
maintenance of the emission control system for the vent on a fixed roof
tank at a new or existing source.
    We began our examination by reviewing the title V permits for each
facility subject to the Site Remediation NESHAP. In this review, we
searched for facilities that had tanks subject to the emissions
standards of the Site Remediation NESHAP and for any permit
requirements pertaining to periods of routine maintenance of a control
device for a tank. From this review, several facilities were found to
have tanks subject to the Site Remediation NESHAP emission standards.
While the current provisions of the Site Remediation NESHAP minimize
emissions by limiting the duration of the bypass of a control device
for planned routine maintenance to 240 hours per year, no additional
permit conditions were found for these facilities for periods of time
when the tank control device was not operating. We also reviewed other
NESHAP to examine the requirements that apply to similar tanks. From
the review of these NESHAP, we found that the Hazardous Organic NESHAP
(HON) and several other NESHAP, including, but not limited to, those
for Group I Polymers and Resins, Group IV Polymers and Resins, OSWRO,
Pharmaceuticals Production, and Pesticide Active Ingredient Production
with similar vapor pressure and threshold capacities have provisions
that minimize HAP emissions during periods of planned routine
maintenance. These provisions minimize HAP emissions by limiting the
duration of planned routine maintenance to 240 hours per year. The
Pharmaceuticals Production and Pesticide Active Ingredient Production
NESHAP also allow a facility to request an extension of up to an
additional 120 hours per year on the condition that no material is
added to the tank during such requested extension period. The Amino and
Phenolic Resins NESHAP includes the 240-hour provision described above
and also prohibits sources from increasing the level of material in
tanks during that time to minimize emissions. With these provisions,
fixed roof tanks' emissions are limited to breathing losses, and the
tanks do not need to be emptied and degassed to perform routine
maintenance. Based on our review of these permits and NESHAP, we have
determined that the MACT floor level of control for fixed roof tank
vents at existing Site Remediation sources is the minimization of
emissions by limiting the duration of planned routine maintenance
periods in which the control device may be bypassed to 240 hours per
year. Also based on this review, we identified one above-the-floor
option, which is to add a work practice to prohibit the addition of
material to the tank during the planned routine maintenance period when
the tank control device is bypassed.\15\
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    \15\ Impacts Associated with the Routine Maintenance Provisions
for Storage Tanks in the Site Remediation Source Category.
Memorandum from Lesley Stobert, SC&A, to Matt Witosky, available in
the docket for this action, Docket ID No. EPA HQ-OAR-2018-0833.
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    We evaluated the impacts of the identified beyond-the-floor control
option. We estimate that there are one to 10 facilities in the category
that would need to control one or more tanks during periods when the
primary emission control system is undergoing planned routine
maintenance. We have assumed an equal distribution of one to five tanks
at 10 facilities, for a total of 30 tanks in the source category. To
comply with the work practice of not adding material to the tank during
planned routine maintenance periods when the tank control device is
bypassed, we anticipate no additional equipment would be needed and no
additional costs would be incurred. We estimate this option would
reduce emissions by up 76 lbs./year per tank and 2,280 lbs./year (1.1
tpy) for the source category (i.e., 30 tanks).
    Based on our analysis, the identified beyond-the-floor option is
reasonable, given the level of HAP emissions reduction that would be
achieved with this work practice and the absence of additional costs.
Accordingly, we are revising the Site Remediation MACT standards to
allow owners or operators of fixed roof vessels at new and existing
affected Site Remediation facilities to perform planned routine
maintenance of the emission control system for up to 240 hours per
year, provided there are no working losses from the tank during that
time.
    This work practice standard is being established in accordance with
CAA section 112(h). We note that the tank requirements in this rule
were originally promulgated as CAA section 112(h) standards, which
established two control options. One option is for the installation of
a floating roof pursuant to 40 CFR part 63, subpart WW. This option is
a combination of design, equipment, work practice, and operational
standards. The other option is to install a conveyance system (pursuant
to 40 CFR part 63, subpart DD) and route the emissions to a control
device that achieves a 95-percent reduction in HAP emissions or that
achieves a specific outlet HAP concentration. This second option is a
combination of design standards, equipment standards, operational
standards, and a percent reduction or outlet concentration. See the
preamble to the original rulemaking for 40 CFR part 63, subpart GGGGG
at 67 FR 49398 (July 30, 2002). The work practice requirement added in
this action also fulfills the purposes of section 112(h)(1) of the CAA,
which calls on the Administrator to include requirements in work