[Federal Register Volume 89, Number 199 (Tuesday, October 15, 2024)]
[Rules and Regulations]
[Pages 83296-83336]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-22823]



[[Page 83295]]

Vol. 89

Tuesday,

No. 199

October 15, 2024

Part IV





 Environmental Protection Agency





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40 CFR Part 60





New Source Performance Standards Review for Volatile Organic Liquid 
Storage Vessels (Including Petroleum Liquid Storage Vessels); Final 
Rule

Federal Register / Vol. 89 , No. 199 / Tuesday, October 15, 2024 / 
Rules and Regulations

[[Page 83296]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2023-0358; FRL-10655-02-OAR]
RIN 2060-AV93


New Source Performance Standards Review for Volatile Organic 
Liquid Storage Vessels (Including Petroleum Liquid Storage Vessels)

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is finalizing 
amendments to the new source performance standards (NSPS) for Volatile 
Organic Liquid Storage Vessels (Including Petroleum Liquid Storage 
Vessels) pursuant to the review required by the Clean Air Act (CAA). 
The EPA is finalizing revisions to the NSPS that are applicable to 
volatile organic liquid (VOL) storage vessels that commence 
construction, reconstruction, or modification after October 4, 2023, 
under a new NSPS subpart, as well as amendments to an existing subpart. 
In the new NSPS subpart Kc, the EPA is finalizing requirements to 
reduce the vapor pressure applicability thresholds and revise the 
volatile organic compound (VOC) standards to reflect the best system of 
emission reduction (BSER) for affected storage vessels. In addition, 
the EPA is finalizing degassing emission controls; clarification of 
startup, shutdown, and malfunction (SSM) requirements; additional 
monitoring requirements; and other technical improvements

DATES: This final rule is effective on October 15, 2024. The 
incorporation by reference of certain publications listed in the rule 
is approved by the Director of the Federal Register as of October 15, 
2024.

ADDRESSES: The EPA has established a docket for this action under 
Docket ID No. EPA-HQ-OAR-2023-0358. 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 (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only as 
portable document format (PDF) versions that can only be accessed on 
the EPA computers in the docket office reading room. Certain databases 
and physical items cannot be downloaded from the docket but may be 
requested by contacting the Public Reading Room at (202) 566-1744. The 
docket office has up to 10 business days to respond to these requests. 
With the exception of such material, publicly available docket 
materials are available electronically in Regulations.gov or on the EPA 
computers in the Public Reading Room 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 (202) 566-1744, and the telephone 
number for the EPA Docket Center is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: Mr. Michael Cantoni III, Sector 
Policies and Programs Division (E143-01), Office of Air Quality 
Planning and Standards, U.S. Environmental Protection Agency, 109 T.W. 
Alexander Drive, P.O. Box 12055, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-5593; and email address: 
<a href="/cdn-cgi/l/email-protection#5231333c263d3c3b7c3f3b313a33373e123722337c353d24"><span class="__cf_email__" data-cfemail="87e4e6e9f3e8e9eea9eaeee4efe6e2ebc7e2f7e6a9e0e8f1">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: 
    Preamble acronyms and abbreviations. Throughout this document the 
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. 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:

AMEL alternative means of emissions limitation
API American Petroleum Institute
ASTM American Society for Testing and Materials
AVO audible, visual, and olfactory
BSER best system of emission reduction
CAA Clean Air Act
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
EFR external floating roof
EIA economic impact analysis
EJ environmental justice
EPA Environmental Protection Agency
FR Federal Register
gal gallons
HAP hazardous air pollutant(s)
IBR incorporate by reference
ICR information collection request
IFR internal floating roof
kg/hr kilograms per hour
kPa kilopascals
LEL lower explosive limit
m3 cubic meters
MON Miscellaneous Organic Chemical Manufacturing NESHAP
MTVP maximum true vapor pressure
NAICS North American Industry Classification System
NESHAP national emission standards for hazardous air pollutants
NSPS new source performance standards
NTAA National Tribal Air Association
NTTAA National Technology Transfer and Advancement Act
OMB Office of Management and Budget
PDF portable document format
PRA Paperwork Reduction Act
PRD pressure relief device
ppmv parts per million by volume
psia pounds per square inch absolute
psig pounds per square inch gauge
RFA Regulatory Flexibility Act
RIN Regulatory Information Number
SCAQMD South Coast Air Quality Management District
SSM startup, shutdown, and malfunction
STERPP 2000 U.S. EPA Storage Tank Emission Reduction Partnership 
Program
UMRA Unfunded Mandates Reform Act
VCU vapor combustion unit
VOC volatile organic compound(s)
VOL volatile organic liquid

    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 Review
II. Background
    A. What is the statutory authority for this action?
    B. How does the EPA perform the NSPS review?
    C. What is the source category regulated in this final action?
    D. What outreach and engagement did the EPA conduct?
III. What changes did we propose for the VOL Storage Vessel NSPS?
IV. What actions are we finalizing and what is our rationale for 
such decisions?
    A. Revised NSPS for VOL Storage Vessels That Commenced 
Construction, Reconstruction, or Modification After July 23, 1984, 
and on or Before October 4, 2023
    B. Revised NSPS for VOL Storage Vessels That Commenced 
Construction, Reconstruction, or Modification After October 4, 2023
    C. NSPS Subpart Kc Without Startup, Shutdown, and Malfunction 
Exemptions
    D. Testing, Monitoring, and Inspection Requirements
    E. Recordkeeping and Electronic Reporting
    F. Other Final Amendments
    G. Effective Date and Compliance Dates
V. Summary of Cost, Environmental, and Economic Impacts
    A. What are the air quality impacts?
    B. What are the cost impacts?
    C. What are the economic impacts?
    D. What are the benefits?
    E. What analysis of environmental justice did we conduct?
VI. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive

[[Page 83297]]

Order 14094: Modernizing Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR Part 51
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations and Executive Order 14096: Revitalizing Our Nation's 
Commitment to Environmental Justice for All
    K. Congressional Review Act (CRA)

I. General Information

A. Does this action apply to me?

    The source category that is the subject of this final action is 
composed of VOL storage vessels (including petroleum liquid storage 
vessels) regulated under CAA section 111, NSPS. The 2022 North American 
Industry Classification System (NAICS) codes for the source category 
are 325, 324, and 422710. The NAICS codes serve as a guide for readers 
outlining the type of entities that this final action is likely to 
affect. The NSPS codified in 40 CFR part 60, subpart Kc, are directly 
applicable to affected facilities that begin construction, 
reconstruction, or modification after October 4, 2023. Final amendments 
to 40 CFR part 60, subpart Kb, are applicable to affected facilities 
that begin construction, reconstruction, or modification after July 23, 
1984, and before October 4, 2023. Federal, State, local, and Tribal 
government entities that own and/or operate VOL storage vessels are 
affected by this action. If you have any questions regarding the 
applicability of this action to a particular entity, you should 
carefully examine the applicability criteria found in 40 CFR part 60, 
subparts Kb and Kc, and consult the person listed in the FOR FURTHER 
INFORMATION CONTACT section of this preamble, your State air pollution 
control agency with delegated authority for NSPS, or your EPA Regional 
Office.

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 is available on the internet at https://www.epa.gov/stationary-sources-air-pollution/volatile-organic-liquid-storage-vessels-including-petroleum. Following publication in the Federal 
Register, the EPA will post the Federal Register version of the final 
rule and key technical documents at this same website.

C. Judicial Review and Administrative Review

    Under 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 
December 16, 2024. 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 ``[o]nly 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 convene a proceeding for 
reconsideration, ``[i]f the person raising an objection can demonstrate 
to the EPA 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 to us should submit a Petition for Reconsideration to 
the Office of the Administrator, U.S. Environmental Protection Agency, 
Room 3000, WJC West 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. Environmental Protection Agency, 1200 Pennsylvania 
Ave. NW, Washington, DC 20460.

II. Background

A. What is the statutory authority for this action?

    The EPA's authority for this final rule is CAA section 111, which 
governs the establishment of standards of performance for stationary 
sources. Section 111(b)(1)(A) of the CAA requires the EPA Administrator 
to list categories of stationary sources that in the Administrator's 
judgment cause or contribute significantly to air pollution that may 
reasonably be anticipated to endanger public health or welfare. The EPA 
must then issue performance standards for new (and modified or 
reconstructed) sources in each source category pursuant to CAA section 
111(b)(1)(B). These standards are referred to as new source performance 
standards, or NSPS. The EPA has the authority to define the scope of 
the source categories, determine the pollutants for which standards 
should be developed, set the emission level of the standards, and 
distinguish among classes, types, and sizes within categories in 
establishing the standards.
    CAA section 111(b)(1)(B) requires the EPA to ``at least every 8 
years review and, if appropriate, revise'' new source performance 
standards. However, the Administrator need not review any such standard 
if the ``Administrator determines that such review is not appropriate 
in light of readily available information on the efficacy'' of the 
standard. When conducting a review of an existing performance standard, 
the EPA has the discretion and authority to add emission limits for 
pollutants or emission sources not currently regulated for that source 
category.
    In setting or revising a performance standard, CAA section 
111(a)(1) provides that performance standards are to reflect ``the 
degree of emission limitation achievable through the application of the 
best system of emission reduction which (taking into account the cost 
of achieving such reduction and any nonair quality health and 
environmental impact and energy requirements) the Administrator 
determines has been adequately demonstrated.'' The term ``standard of 
performance'' in CAA section 111(a)(1) makes clear that the EPA is to 
determine both the best system of emission reduction for the regulated 
sources in the source category and the degree of emission limitation 
achievable through application of the BSER. The EPA must then, under 
CAA section 111(b)(1)(B), promulgate standards of performance for new 
sources that reflect that level of stringency. CAA section 111(b)(5) 
generally precludes the EPA from prescribing a particular technological 
system that must be used to comply with a standard of performance. 
Rather, sources can select any measure or combination of measures that 
will achieve the standard. CAA section 111(h)(1) authorizes the 
Administrator to promulgate ``a design, equipment, work practice, or 
operational standard, or combination thereof'' if in his or her 
judgment, ``it is not feasible to prescribe

[[Page 83298]]

or enforce a standard of performance.'' CAA section 111(h)(2) provides 
the circumstances under which prescribing or enforcing a standard of 
performance is ``not feasible,'' such as when the pollutant cannot be 
emitted through a conveyance designed to emit or capture the pollutant 
or when there is no practicable measurement methodology for the 
particular class of sources.
    Pursuant to the definition of new source in CAA section 111(a)(2), 
standards of performance apply to facilities that begin construction, 
reconstruction, or modification after the date of publication of the 
proposed standards in the Federal Register. Under CAA section 
111(a)(4), ``modification'' means any physical change in, or change in 
the method of operation of, a stationary source that increases the 
amount of any air pollutant emitted by such source or which results in 
the emission of any air pollutant not previously emitted. Changes to an 
existing facility that do not result in an increase in emissions are 
not considered modifications. Under the provisions in 40 CFR 60.15, 
``reconstruction'' means the replacement of components of an existing 
facility such that: (1) the fixed capital cost of the new components 
exceeds 50 percent of the fixed capital cost that would be required to 
construct a comparable entirely new facility; and (2) it is 
technologically and economically feasible to meet the applicable 
standards. Pursuant to CAA section 111(b)(1)(B), the standards of 
performance or revisions thereof shall become effective upon 
promulgation.

B. How does the EPA perform the NSPS review?

    As noted in section II.A. of this preamble, CAA section 111 
requires the EPA to, at least every 8 years, review and, if 
appropriate, revise the standards of performance applicable to new, 
modified, and reconstructed sources. If the EPA revises the standards 
of performance, the standards must reflect the degree of emission 
limitation achievable through the application of the BSER considering 
the cost of achieving such reduction and any nonair quality health and 
environmental impact and energy requirements. CAA section 111(a)(1).
    In reviewing an NSPS to determine whether it is ``appropriate'' to 
revise the standards of performance, the EPA evaluates the statutory 
factors, which may include consideration of the following information:
    <bullet> Expected growth for the source category, including how 
many new facilities, reconstructions, and modifications may trigger 
NSPS in the future.
    <bullet> Pollution control measures, including advances in control 
technologies, process operations, design or efficiency improvements, or 
other systems of emission reduction, that are ``adequately 
demonstrated'' in the regulated industry.
    <bullet> Available information from the implementation and 
enforcement of current requirements that indicates that emission 
limitations and percent reductions beyond those required by the current 
standards are achieved in practice.
    <bullet> Costs (including capital and annual costs) associated with 
implementation of the available pollution control measures.
    <bullet> The amount of emission reductions achievable through 
application of such pollution control measures.
    <bullet> Any non-air quality health and environmental impact and 
energy requirements associated with those control measures.
    In evaluating whether the cost of a particular system of emission 
reduction is reasonable, the EPA considers various costs associated 
with the particular air pollution control measure or a level of 
control, including capital costs and operating costs, and the emission 
reductions that the control measure or particular level of control can 
achieve. The Agency considers these costs in the context of the 
industry's overall capital expenditures and revenues. The Agency also 
considers cost effectiveness analysis as a useful metric and as a means 
of evaluating whether a given control achieves emission reduction at a 
reasonable cost. A cost effectiveness analysis allows comparisons of 
relative costs and outcomes (effects) of two or more options. In 
general, cost effectiveness is a measure of the outcomes produced by 
resources spent. In the context of air pollution control options, cost 
effectiveness typically refers to the annualized cost of implementing 
an air pollution control option divided by the amount of pollutant 
reductions realized annually.
    After the EPA evaluates the statutory factors, the EPA compares the 
various systems of emission reductions and determines which system is 
``best'' and therefore represents the BSER. The EPA then establishes a 
standard of performance that reflects the degree of emission limitation 
achievable through the implementation of the BSER. In performing this 
analysis, the EPA can determine whether subcategorization is 
appropriate based on classes, types, and sizes of sources, and may 
identify a different BSER and establish different performance standards 
for each subcategory. The result of the analysis and the BSER 
determination leads to standards of performance that apply to 
facilities that begin construction, reconstruction, or modification 
after the date of publication of the proposed standards in the Federal 
Register. Because the NSPS reflect the BSER under conditions of proper 
operation and maintenance, in doing its review, the EPA also evaluates 
and determines the proper testing, monitoring, recordkeeping, and 
reporting requirements needed to ensure compliance with the emission 
standards.

C. What is the source category regulated in this final action?

    The EPA first promulgated NSPS for petroleum liquid storage vessels 
on March 8, 1974 (39 FR 9317). These standards of performance are 
codified in 40 CFR part 60, subpart K, and are applicable to sources 
that commence construction, modification, or reconstruction after June 
11, 1973, and prior to May 19, 1978. These standards were amended 
several times before 1980, when the EPA proposed to establish revised 
NSPS for petroleum liquid storage vessels as NSPS subpart Ka (45 FR 
23379; April 4, 1980). In 1982, the EPA published a list of priority 
sources for which additional NSPS should be established (47 FR 951; 
January 8, 1982), and VOL storage vessels at synthetic organic chemical 
manufacturers were included in the priority list.
    Pursuant to the EPA's authority under CAA section 111, the Agency 
proposed (49 FR 29698; July 23, 1984) and promulgated (52 FR 11420; 
April 8, 1987) NSPS for VOL storage vessels (including petroleum liquid 
storage vessels) for which construction, reconstruction, or 
modification commenced after July 23, 1984, as NSPS subpart Kb.\1\ NSPS 
subpart Kb regulates storage vessels with a capacity of 75 cubic meters 
(m\3\) (~20,000 gallons) or more that store VOLs with a maximum true 
vapor pressure (MTVP) greater than or equal to 15.0 kilopascals (kPa) 
(~2.18 pounds per square inch absolute (psia)) and from storage vessels 
with a capacity of 151 m\3\ (~40,000 gallons) or more that store 
organic liquids with an MTVP

[[Page 83299]]

greater than or equal to 3.5 kPa (~0.51 psia). VOC emissions controls 
are required on storage vessels with a capacity of 75 m\3\ (~20,000 
gallons) or more that store VOLs with an MTVP greater than or equal to 
27.6 kPa (~4.0 psia) and from storage vessels with a capacity of 151 
m\3\ (~40,000 gallons) or more that store organic liquids with an MTVP 
greater than or equal to 5.2 kPa (~0.75 psia). NSPS subpart Kb emission 
controls include the use of an external floating roof (EFR), an 
internal floating roof (IFR), or a closed vent system and a control 
device (see 40 CFR 60.110b(a) and 40 CFR 60.112b(a) and 
(b)).<SUP>2 3</SUP> NSPS subpart Kb also specifies testing, monitoring, 
recordkeeping, reporting, and other requirements in 40 CFR 60.113b 
through 40 CFR 60.116b to ensure compliance with the standards. Storage 
vessels with an EFR consist of an open-top cylindrical steel shell 
equipped with a deck that floats on the surface (commonly referred to 
as a floating ``roof'') of the stored liquid. Storage vessels with an 
IFR are fixed roof vessels \4\ that also have a deck internal to the 
vessel that floats on the liquid surface (commonly referred to as an 
internal floating ``roof'') within the fixed roof vessel.
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    \1\ On October 15, 2003 (68 FR 59328), the EPA finalized 
amendments to NSPS subpart Kb to exempt certain storage vessels by 
capacity and vapor pressure, exempt process tanks, and add a process 
tank definition. At the same time, the EPA also amended the rule to 
exempt storage vessels that are subject to the National Emission 
Standards for Hazardous Air Pollutants (NESHAP) for Solvent 
Extraction of Vegetable Oil Production.
    \2\ All affected storage vessels storing organic liquids with a 
true vapor pressure of 76.6 kPa or more must use a closed vent 
system and a control device. See 40 CFR 60.112b(b).
    \3\ As part of NSPS subpart Kb, the EPA proposed (49 FR 29703; 
July 23, 1984) and finalized (52 FR 11421; April 8, 1987) that the 
best demonstrated technology for vessels storing VOL liquids with 
vapor pressures less than 76.6 kPa ([cong]11.1 psia) consists of an 
IFR with a liquid-mounted or mechanical shoe primary seal and 
controlled fittings or an EFR with a liquid-mounted or mechanical 
shoe primary seal and gasketed fittings. For vessels with greater 
vapor pressures, the EPA determined the best demonstrated technology 
to be a closed vent system and control device.
    \4\ A fixed roof storage vessel consists of a cylindrical steel 
shell with a permanently affixed roof, which may vary in design from 
cone or dome-shaped to flat.
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    The standards set in NSPS subpart Kb for storage vessels with an 
EFR or IFR are a combination of design, equipment, work practice, and 
operational standards set pursuant to CAA section 111(h). These 
standards require, among other things, that a rim seal be installed 
continuously around the circumference of the vessel (between the inner 
wall of the vessel and the floating roof) to prevent VOC emissions from 
escaping to the atmosphere through gaps between the floating roof and 
the inner wall of the storage vessel. For IFRs, NSPS subpart Kb allows 
a single liquid-mounted or mechanical shoe primary seal (to be used 
with or without a secondary seal), or a vapor-mounted primary seal in 
combination with a secondary seal. For EFRs, NSPS subpart Kb allows 
either a liquid-mounted or mechanical shoe primary seal, both of which 
must be used with a secondary seal; vapor-mounted primary seals are not 
allowed for EFRs. NSPS subpart Kb also requires numerous deck fittings 
\5\ on the floating roof to be equipped with a gasketed cover or lid 
that is kept in the closed position at all times (i.e., no visible 
gap), except when the device (deck fitting) is in actual use, to 
prevent VOC emissions from escaping through the deck fittings. In 
addition, NSPS subpart Kb requires owners and operators to conduct 
visual inspections to check for defects in the floating roof, rim 
seals, and deck fittings (e.g., holes, tears, or other openings in the 
rim seal, or covers and lids on deck fittings that no longer close 
properly) that could expose the liquid surface to the atmosphere and 
potentially result in VOC emission losses through rim seals and deck 
fittings.\6\
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    \5\ Numerous fittings pass through or are attached to floating 
decks to accommodate structure support components or to allow for 
operational functions. Typical deck fittings include, but are not 
limited to access hatches, gauge floats, gauge hatch/sample wells, 
rim vents, deck drains, deck legs, vacuum breakers, pontoon covers 
and guidepoles. IFR storage vessels may also have deck seams, fixed 
roof support columns, ladders, and/or stub drains.
    \6\ For details about storage vessel emissions, refer to the 
Compilation of Air Pollutant Emission Factors, Volume 1: Stationary 
Point and Area Sources, AP-42, Fifth Edition, Chapter 7: Liquid 
Storage Tanks, dated June 2020 which is available at: https://www.epa.gov/air-emissions-factors-andquantification/ap-42-compilation-air-emissions-factors.
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    NSPS subpart Kb includes two primary alternative means of 
compliance. Owners or operators may either comply with the consolidated 
air rule provisions for storage vessels in 40 CFR part 65, subpart C, 
or comply with the national emission standards for hazardous air 
pollutants (NESHAP) for storage vessels in 40 CFR part 63, subpart WW 
(NESHAP subpart WW). The substantive control requirements in these 
rules are the same as in NSPS subpart Kb although they may have slight 
differences in the details of the fitting and inspection requirements.
    The EPA proposed the current review of the VOL storage vessels 
(including petroleum liquid storage vessels) NSPS subpart Kb on October 
4, 2023. We received 29 comments from industry, environmental groups, 
State environmental agencies, and others during the comment period. 
After the conclusion of the comment period, we received one additional 
comment in February 2024. A summary of the more significant comments we 
received regarding the proposed rule and our responses are provided in 
this preamble. A summary of all other public comments on the proposal 
and the EPA's responses to those comments is available in New Source 
Performance Standards for Volatile Organic Liquid Storage Vessels, 
Background Information for Final Amendments, Summary of Public Comments 
and Responses, Docket ID No. EPA-HQ-OAR-2023-0358. In this action, the 
EPA is finalizing decisions and revisions pursuant to CAA section 
111(b)(1)(B) review for VOL storage vessels after our considerations of 
all the comments received.

D. What outreach and engagement did the EPA conduct?

    As part of this rulemaking, the EPA engaged and consulted with the 
public, including communities with environmental justice (EJ) concerns, 
through interactions such as providing a webinar, offering information 
on the website for this rule, and informing the public of the proposed 
action by sending notifications with summaries of the action and 
information on how to comment. These opportunities allowed the EPA to 
hear directly from the public, especially communities potentially 
impacted by this final action. The webinar slides can be found in the 
docket for this rule (Docket ID No. EPA-HQ-OAR-2023-0358).
    Prior to proposal publication, the EPA conducted outreach by 
providing background on the source category and the existing 
requirements of NSPS subpart Kb on the September 19, 2023, EJ National 
Community Engagement call and on the August 31, 2023, National Tribal 
Air Association (NTAA) call. After publication, the EPA conducted a 
community outreach webinar on October 24, 2023, which was focused on 
discussing the details of the proposed rulemaking and how to provide 
comment on the proposed rule. Additionally, the EPA discussed the 
contents of the proposed rule on an October 26, 2023, NTAA call and 
encouraged interested parties to submit comments. The EPA received a 
request from one Tribe for consultation. On November 8, 2023, the EPA 
met with that Tribe for the purposes of discussing NSPS subpart Kc and 
other issues but was unable to conduct consultation on this specific 
rulemaking.

III. What changes did we propose for the VOL Storage Vessel NSPS?

    On October 4, 2023, the EPA proposed the current review of the VOL 
Storage Vessel NSPS. In that action, we proposed the following actions 
under NSPS subpart Kc:

[[Page 83300]]

    <bullet> General applicability thresholds that include VOL storage 
vessels greater than or equal to 20,000 gallons (gal).
    <bullet> Vapor pressure thresholds for controlled VOL storage 
vessels greater than or equal to 40,000 gal (151 m\3\) with MTVPs 
greater than or equal to 0.5 psia (3.4 kPa).
    <bullet> Vapor pressure thresholds for controlled VOL storage 
vessels greater than or equal to 20,000 gal (75.7 m\3\) and less than 
40,000 gal (151 m\3\) with MTVPs greater than or equal to 1.5 psia 
(10.3 kPa).
    <bullet> Improved standards of performance for vessels that have 
IFRs, EFRs, and closed vent systems routed to a control device, fuel 
gas system, or process designed to achieve an average 98 percent 
control efficiency.
    <bullet> Updated standards of performance for IFR storage vessels 
that include improved seal system requirements, guidepole 
configurations reflective of the 2000 U.S. EPA Storage Tank Emission 
Reduction Partnership Program (STERPP), and annual lower explosive 
limit (LEL) monitoring.
    <bullet> Updated standards of performance for EFR storage vessels 
that include requirements for welded deck seams, and improved guidepole 
requirements.
    <bullet> Updated standards for closed vent systems that are routed 
to a control device, fuel gas system, or process and include 
requirements for preventing emissions venting to atmosphere, annual EPA 
Method 21 monitoring, and quarterly audible, visual, and olfactory 
(AVO) inspections.
    <bullet> Degassing standards of performance for VOL storage vessels 
greater than or equal to 1 million gal (3,790 m\3\) with MTVPs greater 
than or equal to 1.5 psia (10.3 kPa).
    <bullet> Modification provisions dependent upon an increase of the 
MTVP from the VOLs previously stored.
    <bullet> Improved testing, monitoring, and inspection requirements.
    <bullet> Provisions establishing that emission limitations apply at 
all times, including during periods of SSM.
    <bullet> Improved recordkeeping and reporting requirements, which 
include the implementation of electronic reporting.
    Additionally, we proposed to add electronic reporting requirements 
to the existing subpart, NSPS subpart Kb.

IV. What actions are we finalizing and what is our rationale for such 
decisions?

    The EPA is finalizing revisions to the NSPS for VOL storage vessels 
pursuant to CAA section 111(b)(1)(B) review. The EPA is promulgating 
the NSPS revisions in a new subpart, 40 CFR part 60, subpart Kc. The 
new NSPS subpart is applicable to affected sources constructed, 
modified, or reconstructed after October 4, 2023.
    Under NSPS subpart Kc, we are finalizing standards that reflect the 
BSER for affected storage vessels. The rulemaking proposal included 
different criteria thresholds for general applicability versus for 
storage vessel control. Under the finalized general applicability 
provisions, the EPA has included a new exemption for storage vessels 
that only store VOL with an MTVP less than 0.25 psia (1.7 kPa) in 
response to comments we received asking to eliminate recordkeeping 
requirements for storage vessels with vapor pressures well below the 
thresholds for which controls are required. We are finalizing the 
capacity and vapor pressure thresholds for which controls are required 
as proposed. Specifically, we are finalizing control requirements for: 
(1) VOL storage vessels greater than or equal to 40,000 gal (151 m\3\) 
with MTVPs greater than or equal to 0.5 psia (3.4 kPa); and (2) VOL 
storage vessels greater than or equal to 20,000 gal (75.7 m\3\) and 
less than 40,000 gal (151 m\3\) with MTVPs greater than or equal to 1.5 
psia (10.3 kPa). We are also finalizing modification provisions similar 
to those proposed, but we are clarifying that a modification occurs 
when a ``. . . storage vessel is used to store VOL that has a greater 
maximum true vapor pressure than all VOL historically stored or 
permitted.''
    In addition to updates involving applicability and modification, we 
are finalizing the proposed standards for storage vessels with IFRs, 
EFRs, and closed vent systems routed to a control device, fuel gas 
system, or process, with minor adjustments based on feedback. Regarding 
degassing controls, we are finalizing the provisions with minor 
revisions to require controls on nonflammable liquid degassing until 
reaching 5,000 parts per million by volume (ppmv) as methane vapor 
space concentration rather than the 10 percent LEL.
    We are finalizing testing, monitoring, and inspection requirements 
as proposed, with some minor revisions that involve matters such as the 
timelines and frequency for completing inspections, LEL monitoring 
calibration procedures, inspection requirements, and the MTVP 
determinations. Similarly, we are finalizing the recordkeeping and 
reporting requirements with minor revisions from the proposal involving 
matters such as pressure releases, closed vent system monitoring, and 
reporting deadlines.
    This action also finalizes standards of performance in NSPS subpart 
Kc that apply at all times including during periods of SSM and other 
changes such as electronic reporting, as proposed. This action also 
finalizes revisions in NSPS subpart Kb to require electronic reporting 
as proposed.

A. Revised NSPS for VOL Storage Vessels That Commenced Construction, 
Reconstruction, or Modification After July 23, 1984, and on or Before 
October 4, 2023

    We proposed revisions to NSPS subpart Kb to add electronic 
reporting requirements. We are finalizing those revisions as proposed. 
Our response to major comments received on the proposed NSPS subpart Kb 
revisions are provided in this section. Additional public comments 
received and our responses to those comments are include in the Summary 
of Public Comments and Responses document included in Docket ID No. 
EPA-HQ-OAR-2023-0358.
    Comment: One commenter stated that the EPA has no lawful or 
rational basis for not reviewing the flare standards from existing NSPS 
subpart Kb to consider whether to revise NSPS subpart Kb itself. The 
commenter stated that since the EPA has declined to revise the general 
provisions to include specific monitoring requirements to ensure 
compliance, the EPA must revise the NSPS subpart Kb provisions to do 
so, as expressly required by 40 CFR 60.18(d). The commenter stated that 
the EPA's failure to consider whether to revise the NSPS subpart Kb 
standards also violates a consent decree that the EPA entered into to 
resolve environmental groups' lawsuit regarding the EPA's failure to 
comply with its 8-year review obligations under CAA section 
111(b)(1)(B) for the flare provisions from NSPS subpart Kb and other 
NSPS subparts, as well as its 8-year review obligations for certain 
NESHAP subparts.
    Response: The EPA disagrees with this comment. We reviewed NSPS 
subpart Kb and proposed new standards of performance, including new 
design, operating, and monitoring requirements for flares, in the new 
NSPS subpart Kc under CAA section 111(b)(1)(B), which requires that the 
EPA ``. . . review and, if appropriate, revise such standards following 
the same procedures required by this subsection for promulgating such 
standards.''
    CAA section 111(b)(1)(B) does not require retroactive revisions to 
the existing NSPS subpart (i.e., NSPS subpart Kb). Rather, any revision 
to an NSPS must follow the same procedures

[[Page 83301]]

for promulgating such standards under CAA section 111(b)(1)(B). CAA 
section 111 establishes a bifurcated approach to regulating sources. 
Under CAA section 111(b)(1)(B), the EPA is required to promulgate 
standards of performance for new sources, which CAA section 111(a)(2) 
defines as ``any stationary source, the construction or modification of 
which is commenced after the publication of regulations (or, if 
earlier, proposed regulations) prescribing a standard of performance 
under this section which will be applicable to such source.'' Existing 
sources are defined at CAA section 111(a)(6) to mean ``any stationary 
source other than a new source'' and are regulated via a State planning 
process pursuant to CAA section 111(d). Accordingly, the revisions, 
which are being finalized in a new NSPS subpart Kc, apply to sources 
that have commenced construction, reconstruction, or modification after 
October 4, 2023, the proposal date for this action. Sources presently 
subject to NSPS subpart Kb are not, by definition under this statutory 
provision, new sources that could be subjected to the revised standards 
finalized in NSPS subpart Kc. Rather, they are treated as existing 
sources relative to the revised standards finalized in NSPS subpart Kc. 
Revision of the flare provisions in NSPS subpart Kb consistent with the 
changes being finalized with respect to NSPS subpart Kc would be akin 
to directly applying a new standard of performance to existing sources, 
which would be inconsistent with the statutory structure that subjects 
regulation of new and existing sources to separate processes. Further, 
NSPS subpart Kc includes standards prescribed in accordance with CAA 
section 111(h)(1), for flares and other closed vent systems routed to a 
control device designed to achieve a 98 percent reduction in VOC 
emissions. Because CAA section 111(b)(1)(B) does not require revisions 
to the existing NSPS subpart (i.e., NSPS subpart Kb), which continues 
to require 95 percent reduction in VOC emissions when using a flare, 
the EPA did not propose in this rulemaking to reopen NSPS subpart Kb to 
include the new operating and monitoring requirements for flares that 
are needed to assure 98 percent VOC reduction when using a flare.
    Moreover, because regulated sources subject to NSPS subpart Kb were 
not given notice of any such potential change, altering the flare 
requirements in NSPS subpart Kb in the final rule would unfairly put 
sources that have been using flares to comply with NSPS subpart Kb in 
violation of such requirements upon the effective date of this final 
rule. Thus, the EPA is not amending NSPS subpart Kb to reflect the new 
operating and monitoring flare requirements that are included in the 
new NSPS subpart Kc. The EPA notes, however, that as existing sources 
trigger modification, they will become subject to NSPS subpart Kc and 
the new flare requirements in the rule.
    We disagree with the commenter's assertion that our review findings 
violate the consent decree. In that consent decree, the EPA agreed to 
review and, if necessary, revise NSPS subpart Kb. In this case, the EPA 
proposed these revisions as a new subpart to prevent application of 
``new source'' standards to sources that are ``existing'' at the time 
of proposal. Thus, our proposal of NSPS subpart Kc reflects our review 
of NSPS subpart Kb and the revisions to that standard appropriate for 
new sources.
    Comment: One commenter stated that the EPA unlawfully and 
arbitrarily failed to revise existing NSPS subpart Kb to specify that 
the SSM exemptions from the [40 CFR part 60] general provisions do not 
apply. The commenter stated that the EPA has acted outside its 
statutory authority in promulgating the unlawful SSM exemptions from 
the general provisions, and therefore the Agency must revise NSPS 
subpart Kb to make clear that the general provisions' exemptions do not 
apply. The commenter noted that although CAA section 111(b)(1)(B) 
allows the EPA to avoid revising standards when ``review is not 
appropriate in light of readily available information on the efficacy 
of such standard,'' the EPA could not lawfully or rationally invoke 
that exception, since the application of the general provisions' 
exemptions to NSPS subpart Kb is plainly unlawful.
    Response: As noted in the previous comment response, we reviewed 
the current subpart Kb standards, determined a series of appropriate 
revisions, and concluded that these revisions should be completed as a 
separate subpart. We disagree with the commenter that additional 
revision to NSPS subpart Kb is necessary to remove SSM exemptions in 
the 40 CFR part 60 general provisions. First, we note that the 
performance testing requirements in 40 CFR 60.113b(c) clearly indicate 
that the provisions in 40 CFR 60.8 do not apply. As such, objectionable 
language regarding performance test results obtained during SSM events 
is not applicable under NSPS subpart Kb. Second, the SSM exemption in 
40 CFR 60.11(c) is also not applicable to NSPS subpart Kb because NSPS 
subpart Kb does not contain opacity limits. Because the sections in the 
40 CFR part 60 general provisions that contain potentially unlawful SSM 
exemptions are not applicable under NSPS subpart Kb, we found no need 
to further revise NSPS subpart Kb at this time.

B. Revised NSPS for VOL Storage Vessels That Commenced Construction, 
Reconstruction, or Modification After October 4, 2023

    This section describes the key technical standards that were 
proposed, the major comments received on the proposed requirements, our 
responses to those comments, and our rationale for the final 
requirements. Additional public comments received on the technical 
standards and our responses to those comments are included in the 
Summary of Public Comments and Responses document included in Docket ID 
No. EPA-HQ-OAR-2023-0358.
    The EPA is finalizing standards of performance that reflect the 
BSER as well as alternative compliance standards for controlled storage 
vessels. The final standards are consistent with the determinations 
explained in the rulemaking proposal (88 FR 68540-47; October 4, 2023) 
and the analysis detailed in the memorandum Control Options for Storage 
Vessels in Docket ID No. EPA-HQ-OAR-2023-0358. While the EPA has made 
minor adjustments to these standards based on public comment, the BSER 
determination remains unchanged. The adjustments incorporated based on 
public comment are detailed in sections IV.B.4. and 5. of this 
document.
    In summary, the finalized BSER analyses for NSPS subpart Kc are 
dependent on the MTVP of a stored VOL and follow the precedent 
established in NSPS subparts Kb, Ka, and K. In the NSPS subpart K 
proposal, the EPA detailed its justification for the use of equipment 
specification (or work practice) standards. As part of the original 
rulemaking proposal, the EPA explained that equipment specifications 
are the most practical method of regulating storage vessel emissions. 
Direct emission measurements for storage vessels are often impractical, 
and storage vessel emissions are often modeled and dependent on many 
distinguishing factors and variables. The EPA believes that equipment 
specification standards are less burdensome for the storage vessel 
operation and enforcement (38 FR 15406; May 4, 1973). For VOL storage 
vessels with an MTVP less than 11.1 psia, the EPA is finalizing the 
following BSER as proposed (88 FR 68542;

[[Page 83302]]

October 4, 2023): a fixed roof in conjunction with an internal floating 
roof equipped with a liquid-mounted or mechanical shoe primary seal and 
a continuous rim mounted secondary seal, either a flexible fabric 
sleeve or gasketed sliding cover on pipe columns (if any), specific 
STERPP compliant guidepole configurations, and gasketed covers.
    The EPA is also finalizing two alternative compliance options for 
VOL storage vessels with MTVPs less than 11.1 psia as proposed:
    (1) An external floating roof equipped with a liquid-mounted or 
mechanical shoe primary seal and a continuous rim-mounted secondary 
seal, with welded deck seams and both seals meeting certain gap 
requirements, specific guidepole configurations, and gasketed covers; 
or
    (2) A closed vent system routed to a 98 percent effective control 
device, fuel gas system, or process.
    For VOL storage vessels with MTVPs greater than or equal to 11.1 
psia, the EPA is finalizing, as proposed, the BSER as a closed vent 
system routed to a 98 percent effective control device, fuel gas 
system, or process.
1. Vapor Pressure Applicability Thresholds
    NSPS subpart Kb established control requirements, at 40 CFR 
60.112b(a), for storage vessels based on vessel capacity and VOL vapor 
pressures. In our review of NSPS subpart Kb, we assessed the vapor 
applicability thresholds for affected facilities and for controls on 
affected storage vessels to determine whether these thresholds needed 
to be revised for purposes of NSPS subpart Kc. In NSPS subpart Kb there 
are two different sets of vapor pressure applicability thresholds: one 
for determining affected facilities and one for determining controls.
    We proposed to not include specific vapor pressure applicability 
thresholds in defining an affected facility under NSPS subpart Kc. As 
such, the proposed affected facility under NSPS subpart Kc is any 
storage vessel with a capacity of 20,000 gallons or more used to store 
a VOL without exclusion for storage vessels under a set vapor pressure. 
Based on comments received, we are adding an exemption at 40 CFR 
60.110c(b)(8) for storage vessels that only store VOL with an MTVP of 
less than 0.25 psia. This revision from proposal helps to limit burden 
for storage vessels that only store VOL with very low vapor pressures, 
but it does not otherwise impact the control standards proposed for 
NSPS subpart Kc.
    Based on the BSER analysis, we proposed to revise the vapor 
applicability thresholds that require emission controls under NSPS 
subpart Kc. Specifically, we proposed to revise the MTVP threshold for 
smaller storage vessels (those with capacity of at least 20,000 gallons 
but less than 40,000 gallons) to 1.5 psia and for larger storage 
vessels (those with capacity of 40,000 gallons or more) to 0.5 psia. We 
determined that applying controls for VOL at or above these thresholds 
yielded cost-effective emission reductions. We are finalizing these 
thresholds as proposed.
2. Other Applicability Provisions
    NSPS subpart Kb includes several provisions that exempt specific 
groups of VOL storage vessels from applicability under the standard. We 
proposed to carry over several of these exemptions, such as exemptions 
for: storage vessels that operate at coke oven by-product plants; bulk 
gasoline plants; gasoline service stations; pressure vessels; vessels 
attached to mobile vehicles; certain vessels at oil and gas production 
sites prior to custody transfer; and vessels that store beverage 
alcohol. We proposed to remove exemptions under NSPS subpart Kc for 
vessels subject to the NESHAP for solvent extraction for vegetable oil 
production outlined in 40 CFR part 63, subpart GGGG, because the 
standards proposed in NSPS subpart Kc are more stringent than the 
existing NESHAP subpart GGGG standards. We are finalizing these 
applicability provisions as proposed.
    We are adding overlap provisions, based on comments received, to 
allow storage vessels subject to NSPS subparts K, Ka, or Kb, or NESHAP 
subpart WW to comply with the provisions in NSPS subpart Kc because the 
final provisions in NSPS subpart Kc are at least as stringent as those 
in NSPS subparts Kb, Ka, and K, and NESHAP subpart WW. These overlap 
provisions, which were not proposed, allow facilities the operational 
flexibility of simply complying with NSPS subpart Kc if they operate 
storage vessels covered under the specified existing storage vessel 
rules.
    Comment: One commenter stated that the EPA should add an 
alternative compliance option that complying with NSPS subpart Kc 
demonstrates compliance with the floating roof requirements in NESHAP 
subpart WW. Another commenter suggested that the EPA should address 
overlaps between NSPS subpart Kc and other rules consistent with the 
overlap provisions in NSPS subpart Kb.
    Response: There are not overlap provisions in NSPS subpart Kb 
beyond the alternative means of compliance in 40 CFR 60.110b(e). The 
requirements in the rules listed in 40 CFR 60.110b(e) are not 
equivalent to the requirements in NSPS subpart Kc, so we removed these 
alternative means of compliance from NSPS subpart Kc. We agree with 
commenters that including provisions in NSPS subpart Kc to allow 
compliance with the provision in NSPS subpart Kc to be considered 
compliance with the provisions in NSPS subpart Kb or NESHAP subpart WW 
is appropriate because the final requirements in NSPS subpart Kc are at 
least as stringent as those in NSPS subpart Kb and NESHAP subpart WW. 
As such, we have added provisions under 40 CFR 60.110c(h) and 40 CFR 
60.110c(i) that allow owners and operators with storage vessels subject 
to the standards of NSPS subparts K, Ka, and Kb, and NESHAP subpart WW 
to choose to comply with the provisions of NSPS subpart Kc to 
demonstrate compliance. This will allow facilities that may be subject 
to a NESHAP that references NSPS subpart Kb or NESHAP subpart WW but 
also subject to NSPS subpart Kc to consolidate their recordkeeping and 
reporting requirements and comply only with NSPS subpart Kc.
3. Modification Provisions
    For purposes of CAA section 111, modifications are defined as ``. . 
. any physical change in, or change in the method of operation of,'' an 
existing facility which increases the amount of any air pollutant (to 
which a standard applies) emitted into the atmosphere by that facility 
or which results in the emission of any air pollutant (to which a 
standard applies) into the atmosphere not previously emitted. NSPS 
subpart A further provides provisions explaining how a modification is 
identified, as well as defining certain exemptions to those general 
rules. In particular, 40 CFR 60.14(e)(4) states that the ``[u]se of an 
alternative fuel or raw material'' is not considered a modification if 
the existing facility was designed to accommodate that alternative use. 
The EPA proposed, for purposes of NSPS subpart Kc, that a change in the 
liquid stored in the storage vessel to a VOL with a higher MTVP does 
not constitute a ``use of an alternative fuel or raw material'' and 
would be considered a modification under NSPS subpart Kc. Specifically, 
the EPA proposed that a modification occurs when a ``storage vessel is 
used to store VOL that has a greater maximum true vapor pressure than 
the VOL previously stored.''

[[Page 83303]]

    We are finalizing modification provisions similar to those 
proposed, but we are clarifying that a modification occurs when a ``. . 
. storage vessel is used to store VOL that has a greater maximum true 
vapor pressure than all VOL historically stored or permitted.'' 
Commenters were concerned that our proposed language, which referred to 
VOL ``previously stored,'' was ambiguous and potentially limited the 
modification assessment to the most recently stored VOL. We revised the 
text to ``. . . historically stored or permitted . . . ,'' in order to 
clarify our intent that a modification occurs when a new VOL is stored 
that has a higher MTVP than any of the previously stored or permitted 
VOL (and not just the most recently stored VOL). Finally, we are also 
clearly stating, consistent with our discussion in section III.G. of 
the proposal preamble, that the alternative fuel or raw material 
exemption in 40 CFR 60.14(e)(4) does not apply to storage vessels under 
NSPS subpart Kc.
    Comment: Several commenters stated that the language ``the VOL 
previously stored'' in 40 CFR 60.110c(e) is unclear as to whether any 
VOL the storage vessel has previously stored is included, or just the 
VOL stored immediately prior to the change. The proposed 40 CFR 
60.110c(e) language does not clarify which liquids are different, or 
not different, from ``the VOL previously stored.'' Without clarity on 
these points, the rule language is subject to a significant range of 
interpretations, from any stored organic liquid being the same VOL, to 
any de minimis change in liquid properties being a different VOL. 
Another commenter stated that the phrase ``the VOL previously stored'' 
should be removed from 40 CFR 60.110c(e).
    Several commenters requested that storing a VOL with a higher MTVP 
than the liquid previously stored only be considered a modification if 
storing such a liquid would require modification of a facility's 
operating permit. One commenter further stated that using a facility's 
operating permit to determine modification would place an unreasonable 
burden of proof on facility owners or operators. Another commenter 
stated that storage vessels are permitted to handle multiple materials, 
typically using a worst-case scenario, and changing the liquid stored 
in the storage vessel to one above the permitted vapor pressure 
threshold would not necessarily increase emissions since emissions are 
based on other parameters and conditions, such as changing the hourly 
pumping rate, annual throughput, or storage temperature.
    Two commenters noted that storage vessels routinely switch between 
storing materials with lower and higher vapor pressures at certain 
facilities, such as batch chemical plants, refineries, and gasoline 
terminals (for example, annual transitions between summer and winter 
gasoline). According to the commenters, such routine and other 
operational transitions between products do not rise to the level of a 
``modification'' triggering performance standards for new sources under 
the CAA.
    Response: We agree with the commenters that the proposed language 
(``the VOL previously stored'') could be misinterpreted to refer only 
to the VOL stored immediately prior to the change, and that was not our 
intent. For example, if a storage vessel has been used to store both 
summer and winter grades of gasoline, we did not intend that the next 
switch from summer to winter gasoline would trigger a modification of 
the storage vessel. We also agree that owners and operators should not 
trigger modification for introducing VOLs that do not exceed the MTVP 
of all VOLs that may also exist in a permit. We are clarifying the 
regulatory language to match our intent at proposal and reduce burden 
by replacing the phrase ``the VOL previously stored'' with the phrase 
``all VOL historically stored or permitted.'' In discussions with 
industry representatives and the EPA permit specialists, we found that 
specific VOLs are not always listed in permits. Therefore, we are not 
including revisions suggested by some commenters to limit modification 
to only those actions that would require modification of a facility's 
operating permit.
    We disagree with the commenters who suggested that changing the 
volatility of the liquids stored does not increase emissions from the 
storage vessel. We note that the emission rate for modification is 
expressed in kilograms per hour (kg/hr) and that it is not evaluated on 
an annual basis. Even if the facility intends to lower the fill rate to 
limit increases in annual emissions, the storage vessel will still have 
higher emissions (in kg/hr) during periods when the storage vessel is 
not being filled.
    Comment: Several commenters disagreed with the EPA's proposal that 
a change in the liquid stored in the storage vessel to a VOL with a 
higher MTVP does not constitute a ``use of an alternative fuel or raw 
material'' and thus would instead be considered a change in the method 
of operation of a source. According to the commenters, the stored 
materials are fuels or raw materials for some customer or downstream 
user, and there is no requirement for a material to be used at the 
facility where it is being stored for it to be considered a raw 
material or a fuel. According to one commenter, the EPA had determined 
that changing a liquid, regardless of volatility, is not an operational 
change, and another commenter stated that storage vessel service 
changes are the kind of event that the EPA intended to address in 40 
CFR 60.14(e)(4). Other commenters recommended that the EPA retain its 
long-held interpretation that a change of liquids in an existing VOL 
storage vessel does not constitute a ``modification'' triggering 
applicability of NSPS subpart Kc. Commenters also noted that the 
proposed interpretation would arbitrarily apply NSPS subpart Kc to some 
storage vessels, and not to other identical vessels, based on their 
historic use rather than their design capabilities.
    One commenter stated that changing a liquid in a storage vessel is 
not a modification if the material could have been previously 
accommodated without a physical change or a capital expenditure. Some 
commenters requested that the EPA revise proposed 40 CFR 60.110c(e) to 
clearly state that changing the material stored is not a modification 
if the storage vessel could accommodate the new material without a 
physical change or significant capital expenditure. Commenters 
requested that the EPA review historical documents related to NSPS 
subpart Kb and reconfirm these long-held policies regarding 
modification of storage vessels.
    One commenter stated that the EPA's reference to FCC v. Fox 
Television Stations, Inc. for the proposition that it need only 
articulate a ``good reason'' for its ``change in policy'' is misplaced. 
According to the commenter, the EPA is not proposing to amend any of 
its existing regulations setting forth its policy for NSPS triggering 
``modifications.'' Rather, the proposal reflects a reversal of the 
EPA's longstanding interpretation of the CAA and its regulations in 40 
CFR 60.2 and 60.14. Unlike a change in policy, the commenter contends, 
``an agency's interpretation of a statute or regulation that conflicts 
with a prior interpretation is entitled to considerably less deference 
than a consistently held agency view.'' Advanced Energy United, Inc. v. 
FERC (82 F.4th 1095, 1114 (D.C. Cir. 2023) (quoting Thomas Jefferson 
University v. Shalala, 512 U.S. 504 (1994)). Accordingly, it is the 
EPA's long-held interpretation of ``modifications''--for nearly 40 
years--that is entitled to deference. The commenter asserts that

[[Page 83304]]

this is particularly true where, as here, the EPA has not provided a 
justification for the conflicting interpretation or articulated the 
scope of changes in volatility of stored liquids that would actually 
trigger a ``modification.''
    Response: The EPA disagrees with these comments. First, the EPA's 
reliance on FCC v. Fox, 556 U.S. 502 (2009), the controlling case on 
changes in agency policy, is appropriate here. The quote that 
commenters cite above, asserting that an agency's statutory 
interpretation which conflicts with a prior interpretation is 
``entitled to considerably less deference than a consistently held 
view,'' is from Thomas Jefferson University v. Shalala, 512 U.S. 504 
(1994), a 1994 Supreme Court case whose precedent on changes in agency 
policy was displaced by FCC v. Fox, in 2009, 556 U.S. 502. Under FCC v. 
Fox, ``it suffices that the new policy is permissible under the 
statute, that there are good reasons for it, and that the agency 
believes it to be better, which the conscious change of course 
adequately indicates.'' Id. at 515.
    According to the commenters, anything stored in a storage vessel 
should be considered an alternative fuel or raw material and therefore 
any change in the liquid stored should be exempt from being considered 
a modification. We find in this final rule that this interpretation of 
the alternative fuel or raw material exemption as applied to storage 
vessels is inappropriate and often excludes changes in the stored VOL 
that increase emissions and that therefore should trigger additional 
control requirements. The EPA explained its rationale for including 
additional modification provisions in section III.G. of the proposal 
preamble (88 FR 68543; October 4, 2023). The EPA explained that for 
purposes of NSPS subpart Kc, a change in the liquid stored in the 
storage vessel to an organic liquid with a greater MTVP does not 
constitute a ``use of an alternative fuel or raw material'' and would 
be considered a change in the method of operation of the storage 
vessel. The primary function of this affected facility is the storage 
of materials. The VOLs stored in the storage vessel are neither raw 
material nor fuel inputs to a process at the affected facility itself. 
Furthermore, even had the EPA not revisited its interpretation 
regarding the application of 40 CFR 60.14(e)(4), we maintain that 
changing the VOL stored to one with a higher MTVP is a modification (a 
change in the method of operation that results in an increase in the 
emissions rate). The NSPS subpart Kc modification provisions result in 
meaningful emission reductions. For these reasons, the final rulemaking 
appropriately supersedes the general provisions. As such, the EPA is 
finalizing modification provisions such that a change in the liquid 
stored, which results in increased VOC emissions, would be a 
modification under NSPS subpart Kc and is clarifying in 40 CFR 
60.110c(e) that, for the purposes of this source category, the 
exemption at 40 CFR 60.14(e)(4) does not apply.
    The precedent of MTVP dependent standards of performance for VOL 
storage vessels was established as part of NSPS subpart K and has 
informed the establishment of standards for subsequent rulemakings 
under NSPS subparts Ka and Kb. Under these standards, a VOL's MTVP 
(along with a vessel's capacity) has served as a primary mechanism for 
determining suitable standards for control. The amended modification 
provisions will provide meaningful emission reductions from storage 
vessels that would otherwise go unregulated despite satisfying the 
statutory criteria for a modification under CAA section 111(a)(4), as 
explained in this section and at III.G. of the proposal preamble (88 FR 
68543; October 4, 2023). The modification provision, as amended, 
effectively curtails a previously existing loophole which had allowed 
owners and operators to circumvent the standards in NSPS subpart Kb. 
For example, prior to this rulemaking, an uncontrolled fixed roof 
vessel could be constructed and be exempt from NSPS subpart Kb 
standards because it was storing a low vapor pressure VOL. The vessel 
could then change operation to introduce a new material with a higher 
vapor pressure that would otherwise be subject to the NSPS had it been 
stored in the tank at the time of construction, but the owner or 
operator could continue to operate without meeting the floating roof or 
closed vent system and control device standards even if the vessel was 
constructed after the Kb applicability date. Similarly, if an owner or 
operator built floating roof tanks for VOLs with less than 11.1 psia 
and later replaced the liquid stored with a liquid with a vapor 
pressure greater than 11.1 psia, they could thereby circumvent the 
closed vent system and control device requirements under 40 CFR 60.112b 
which are directly dependent on the MTVP of the stored VOL and which 
would otherwise apply. As such, the prior NSPS provided significant 
leeway for owners and operators to circumvent the regulations intended 
to control storage vessel emissions. To address this concern, the EPA 
is finalizing modification provisions such that the MTVP can be used as 
an indicator to determine that a change in the liquid stored, which 
results in increased VOC emissions, would be a modification under NSPS 
subpart Kc.
    The EPA's decision to consider a change in the liquid historically 
stored or permitted to one with a higher vapor pressure to be a 
modification is consistent with both the statutory and regulatory 
definitions of those terms. CAA section 111(a) defines modification to 
mean, ``any physical change in, or change in the method of operation 
of, a stationary source which increases the amount of any air pollutant 
emitted by such source or which results in the emission of any air 
pollutant not previously emitted.'' Similarly, the General Provisions 
to 40 CFR part 60 define modification at 40 CFR 60.2 to mean, ``any 
physical change in, or change in the method of operation of, an 
existing facility which increases the amount of any air pollutant (to 
which a standard applies) emitted into the atmosphere by that facility 
or which results in the emission of any air pollutant (to which a 
standard applies) into the atmosphere not previously emitted.'' And 40 
CFR 60.14 provides a more detailed framework for evaluating 
modifications, which similarly states at paragraph (a) that: ``Except 
as provided under paragraphs (e) and (f) of this section, any physical 
or operational change to an existing facility which results in an 
increase in the emission rate to the atmosphere of any pollutant to 
which a standard applies shall be considered a modification within the 
meaning of section 111 of the Act.'' Thus, the CAA and general 
provisions for 40 CFR part 60 all rely on the same basic two-step 
process: (1) a physical change in, or change in the method of operation 
of, a stationary source; and (2) a resulting increase in emissions. 
Notably, it is not necessary for there to be a physical change at the 
source in the first step if there is a change in the method of 
operation. One or the other will suffice. We address each of these 
criteria in turn.
    First, as proposed, the EPA has determined that a change in the 
liquid stored in a storage vessel constitutes a change in the method of 
operation of a storage vessel. The primary function of this affected 
facility is the storage of materials, and so the only logical ``change 
in the method of operation'' that a storage vessel would undergo is a 
change in the material stored. In other words, whenever a storage 
vessel changes the VOL that is stored, that is a change in that 
facility's method of operation. The EPA's interpretation

[[Page 83305]]

regarding what constitutes a change in the ``method of operation'' for 
storage vessels has not changed with this rulemaking. In explaining the 
applicability of modification under the CAA, in the NSPS subpart Kb 
preamble, the EPA affirmed, ``Few, if any, changes in the physical 
configuration of the storage vessels that would increase emissions are 
anticipated. An operational change that would increase emissions is a 
changing of the stored liquid from a VOC non-emitting liquid to a VOC 
emitting liquid'' (49 FR 29707; July 23, 1984). Thus, the EPA has long 
considered the changing of the stored liquid to meet the statutory 
requirements for an operational change. Second, the changing of the 
stored liquid can lead to an increase of emissions whenever the MTVP of 
the new liquid is greater than the previously stored liquid. Thus, both 
statutory criteria for identifying a modification are met.
    The EPA agrees that we have historically applied the regulatory 
exemption under 60.14(e) for ``use of an alternative fuel or raw 
material'' to storage vessels. In making our decision regarding 
modifications, we reviewed several documents \7\ and questioned both 
industry and enforcement personnel to better understand what changes 
are currently considered modifications. In the NSPS subpart Kb 
preamble, the EPA explained, ``Section 60.14(e) of the General 
Provisions to Part 60 lists several changes that are not considered 
modifications. Among these is the use of raw material, if prior to the 
date of proposal of the standard, the existing facility was designed to 
accommodate that alternative use'' (49 FR 29707; July 23, 1984). 
However, the EPA did not provide any further explanation at that time 
as to why the Agency believed this exemption applied to this affected 
facility, and the Agency has reconsidered the application of that 
exemption for purposes of NSPS subpart Kc. As explained in section 
III.G. of the proposal preamble, when the affected source is a storage 
vessel and not a process unit, we no longer consider a change in the 
liquid stored in the storage vessel (to an organic liquid with a higher 
MTVP) to qualify as a ``use of an alternative fuel or raw material.'' 
As discussed above, the primary function of an affected facility in 
this source category is the storage of materials, and the VOL stored in 
the vessel are neither raw material nor alternative fuel inputs to a 
process at the facility itself. While the storage vessel may store 
liquids that are used as an alternative fuel or raw material used for 
inputs to a process for another facility, it is not reasonable to 
extend application of the exemption to mere storage of the alternative 
fuel or raw material. Accordingly, we no longer believe that the 
exemption should be applied to these factual circumstances by the terms 
of the regulation.
---------------------------------------------------------------------------

    \7\ See, e.g., U.S. EPA Applicability Determination Index, 
Control Number: 0400015, (referencing 40 CFR 60.14(e)(4)-(5)) and 
NSPS subpart Kb Background Information Document (Docket ID No. EPA-
HQ-OAR-2023-0358-0012).
---------------------------------------------------------------------------

    The EPA notes that, the fact that 40 CFR 60.14(e) is framed as 
exempting certain activities from the definition of modification 
indicates that, absent these exemptions, the EPA would consider the 
exempted activity to meet the statutory definition of modification in 
CAA section 111(a)(4). In other words, the EPA created a specific 
provision exempting the ``use of an alternative fuel or raw material'' 
from the regulatory definition of modification because this activity 
would, as the EPA proposed, typically be considered an operational 
change,\8\ a consideration reinforced by the EPA's discussion on 
modification in the NSPS subpart Kb preamble. In this rulemaking, the 
EPA confirms that it does not consider a change in the liquid stored to 
one with a higher MTVP to qualify under this exemption. Moreover, 
irrespective of this determination, the EPA is also finalizing in this 
rulemaking that the exemption in 40 CFR 60.14(e)(4) regarding 
alternative fuel or raw material does not apply to storage vessels.
---------------------------------------------------------------------------

    \8\ This is bolstered when considering the other exemptions in 
40 CFR 60.14(e): a ``replacement'' referred to in (e)(1) and the 
addition of a system or device referred to in (e)(5) is a physical 
change to a facility, and an increase in production rate or an 
increase in hours of operation referred to in (e)(2) or (3) is a 
change in the facility's operation. However, the EPA had a rational 
basis for exempting these particular physical or operational 
changes, as a general matter, from the broader definition of 
modification under the regulations.
---------------------------------------------------------------------------

    While we have determined for purposes of NSPS subpart Kc that a 
change in the liquid stored to a liquid with a higher vapor pressure 
does not constitute the ``use of an alternative fuel or raw material,'' 
we note that even if this exemption would otherwise apply by its terms, 
this rulemaking supersedes the exemption pursuant to 40 CFR 60.14(f), 
because, as explained earlier, we have concluded that it is the better 
policy and consistent with the statutory definition of modification 
based on the facts of how this affected facility operates. The EPA has 
always maintained that there are some sources for which the basic 
exemptions from the standard definition of a modification may not be 
appropriate, and 40 CFR 60.14(f) was included in the general provisions 
to afford the EPA the ability to supersede the general modification 
regulations, the exemption provisions in 40 CFR 60.14(e), for those 
sources for which these provisions should not reasonably be applied. 
The EPA has previously applied specialized interpretations of 
modification for other source categories. For example, in NSPS subpart 
Ja, we included special provisions for the modification of flares at 
petroleum refineries because the basic considerations under 40 CFR 
60.14(e), were generally developed considering process unit emission 
sources. The intermittent operation of a flare makes it difficult to 
use the criteria of 40 CFR 60.14(e) to determine when a flare is 
modified (73 FR 35843; June 24, 2008). In our review of NSPS subpart 
Kb, we identified similar short-comings regarding the ``process unit-
oriented'' modification exemptions as previously applied to storage 
vessels. The specialized modification provision for storage vessels is 
consistent with the CAA statutory requirements, the general definition 
of modification outlined in 40 CFR 60.2 and 60.14, and previous 
determinations that source-specific modification provisions are 
justified for certain source categories. Accordingly, in this 
rulemaking, the EPA confirms that it does not consider a change in the 
liquid stored to one with a higher MTVP to qualify under the exemption 
in 40 CFR 60.14(e)(4), and, as a matter of clarity, irrespective of 
this determination, this rulemaking is superseding the exemption.
    With respect to the comment that the proposed definition of 
modification would arbitrarily apply differently for identical vessels 
based on their historic use rather than their design capabilities, we 
disagree. As stated above, the modification provisions are directly 
dependent on the MTVP of the stored VOL. The precedent of MTVP 
dependent standards of performance for VOL storage vessels was 
established as part of NSPS subpart K and has informed the 
establishment of standards for subsequent rulemakings under NSPS 
subparts Ka and Kb. We are finalizing that storing a VOL with a greater 
MTVP than historically stored or permitted is a modification. We 
determined the BSER and set standards of performance considering 
existing emission controls of modified storage vessels.
    The EPA also disagrees with the comment advocating a requirement 
for capital expenditure to determine whether there is a modification 
and that a capital expenditure clause should be added to the language 
proposed at 40 CFR 110c(e). First, we note that the

[[Page 83306]]

statute at CAA section 111(a)(4) contains no such requirement and the 
general provisions at 40 CFR 60.14(e)(2) only consider whether a 
capital expenditure is needed when considering an exemption from the 
definition of modification tied to increase in production at the 
facility. Critically, neither the statute nor the general provisions 
provide that the determination of whether a modification has occurred 
must be based on a capital expenditure. Thus, the commenters seek to 
impose an additional requirement that is not plainly necessary under 
the statute nor anticipated, either by Congress or by the EPA, without 
an explanation as to why that would be justified for this source 
category. In many cases, a capital expenditure is not needed to change 
the liquid stored in a fixed roof tank. Under the commenter's proposed 
capital expenditure paradigm, an operator of a fixed roof tank used to 
store a low volatility fluid could change to a higher vapor pressure 
fluid and argue that no modification occurred even though the storage 
vessel has changed its method of operation. This would permit the 
resulting emissions increases without the requisite control that the 
statute would otherwise anticipate under such circumstances. It is more 
consistent with the statutory standard to consider the change in the 
liquid stored or permitted as a change in the method of operation and 
then assess whether an increase in the vapor pressure of the liquid 
stored triggers the need for controls (which would require a capital 
expenditure). We found the controls required under proposed NSPS 
subpart Kc are cost effective and meet the BSER criteria, and we see no 
reason to allow uncontrolled modified storage vessels or less stringent 
controls simply because the tank was initially permitted for or stored 
a less volatile liquid.
4. Control Standards for IFRs and EFRs
    The EPA proposed standards of performance that reflect the BSER for 
IFRs as well as alternative compliance standards for controlled storage 
vessel EFRs. The EPA proposed a work practice standard that would 
require new IFR storage vessels be constructed with either a liquid-
mounted or a mechanical shoe primary seal, a rim-mounted secondary 
seal, and fittings on the floating roof that meet certain control 
requirements (e.g., gasketed covers, specific guidepole control 
configurations) mostly consistent with the requirements of fitting 
controls in NSPS subpart Kb. The EPA also proposed that new EFR storage 
vessels be constructed with either a liquid-mounted or a mechanical 
shoe primary seal, a rim-mounted secondary seal, welded deck seams, and 
fittings on the floating roof that meet certain control requirements 
(e.g., gasketed covers, specific guidepole control configurations). 
Except for the guidepole controls, the fitting controls are mostly 
consistent with the requirements of fitting controls in NSPS subpart 
Kb.
    We are finalizing the control requirements for IFRs and EFRs as 
proposed with minor editorial revisions (such as replacing ``roof leg 
supports'' with ``roof supports,'' replacing ``bolted'' with ``bolted 
or otherwise mechanically secured,'' and using consistent language 
regarding requirements for vacuum breaker/automatic bleeder vents). For 
EFRs, we are also adding provisions for emergency roof drains to be 
provided with a slotted membrane fabric cover that covers at least 90 
percent of the area of the opening. As noted by commenters, this 
provision is included in NSPS subpart Kb and the IFR drain requirements 
were inadvertently copied for EFRs in the proposed rule for NSPS 
subpart Kc.
    Comment: One commenter stated the proposed NSPS subpart Kc language 
refers to the floating roof being supported by legs when the floating 
roof is landed, but a common design for IFRs involves suspending the 
IFR from the fixed roof of the tank via cables. The commenter stated 
that proposed language at 40 CFR 60.112c(b)(1) and (4) should be 
revised to accommodate the cable-suspended design alternative. 
Similarly, a commenter recommended the EPA revise the definition of the 
term ``Vacuum breaker/Automatic bleeder vent'' to avoid restricting 
vacuum breakers to the leg-actuated type. Another commenter noted that 
since leg operated vacuum breakers must contact the floor prior to the 
roof support legs, the EPA should consider setting a maximum opening 
distance or clarify that the roof is considered landed when the vacuum 
breaker leg lands. One commenter noted that 40 CFR 60.112c(b)(1) reads 
``. . . and during those intervals when the storage vessel is 
completely emptied or subsequently emptied and refilled'' whereas 40 
CFR 60.112c(c)(1) reads: ``. . . and when the storage vessel is 
completely emptied and subsequently refilled.'' The commenter suggested 
that the requirements for EFRs in 40 CFR 60.112c(c)(1) be revised to be 
consistent with 40 CFR 60.112c(b)(1).
    Response: We agree with the commenters that the language regarding 
roof legs and vacuum breaker/automatic bleeder vents should be 
generalized to allow roof supports other than roof legs and vacuum 
actuations other than leg actuated devices and that consistent language 
should be used for EFRs. While we understand cable suspended roofs are 
specific to IFRs, we generalized the language for EFRs in the event 
different supports are developed for EFRs and to make the language 
consistent between 40 CFR 60.112c(b) and (c). We also revised the use 
of the term ``vacuum breaker'' by replacing it with ``vacuum breaker/
automatic bleeder vent'' because that is the defined term for these 
devices on a floating roof and to distinguish these from vacuum 
breaking devices on a fixed roof. We are also adding a sentence to the 
roof landing monitoring requirements at 40 CFR 60.113c(a)(5) and (b)(8) 
to clarify that the roof is considered landed when the floating roof 
first rests on supports or when the vacuum breaker/automatic bleeder 
vent begins to open, whichever is first. This clarifies that the 
landing alarm must be set at the height the leg-actuated vacuum 
breaker/automatic bleeder vent begins to open the vent, which will be 
prior to the floating roof resting on the roof supports.
    Comment: One commenter stated that the proposed NSPS subpart Kc 
does not address the emergency roof drains that are utilized with 
certain EFRs. The commenter noted that NSPS subpart Kc specifies that 
``stub drains'' are not required to be covered at all, which could be 
understood as exempting EFR emergency roof drains from control. The 
commenter recommended that the EPA clarify, consistent with NSPS 
subpart Kb at 40 CFR 60.112(b)(2)(ii), that each emergency roof drain 
is to be provided with a slotted membrane fabric cover that covers at 
least 90 percent of the area of the opening.
    Response: We agree with the commenter that we inadvertently used 
the language allowing uncontrolled stub drains for IFRs in the proposed 
EFR requirements. We had intended to maintain consistency with the EFR 
drain requirements in NSPS subpart Kb. We agree with the commenter that 
the reference to stub drains for EFRs is not appropriate as stub drains 
are not used for EFRs. In the final rule, we are including the 
requirements to use a slotted membrane fabric cover that covers at 
least 90 percent of the area of the opening at 40 CFR 
60.112c(c)(2)(viii) consistent with the requirements for EFR drains in 
NSPS subpart Kb, as suggested by the commenter.

[[Page 83307]]

5. Control Standards for Closed Vent Systems Routed to a Control 
Device, Fuel Gas System, or Process
    For storage vessels with closed vent systems routed to a control 
device, fuel gas system, or process, the EPA proposed certain design 
requirements for the storage vessel to prevent pressure releases from 
the storage vessel and proposed that control devices must meet 98 
percent or greater emission reduction efficiency. The EPA proposed that 
non-flare thermal combustion devices must conduct performance tests 
initially and at least once every 60 months, in which they establish a 
temperature operating limit to which they must comply at all times. For 
flares, the EPA proposed that flares must meet the operating and 
monitoring requirements consistent with the requirements in the 
Refinery NESHAP (40 CFR 63.670 and 63.671). We are finalizing 
requirements for closed vent systems routed to a control device, fuel 
gas system, or process with some revisions from proposal for reasons 
noted in the following comments and responses.
    First, we are revising the vacuum pressure at which vacuum breaking 
devices must close from -0.1 pounds per square inch gauge (psig) to -
0.1 inches of water (-0.0036 psig) to better reflect common storage 
vessel design requirements. We are also clarifying the language since a 
higher vacuum setting would be a lower absolute pressure and the 
proposed language was potentially ambiguous. The revised provision 
clarifies that any vacuum breaking device on the storage vessel must 
close while the storage vessel is still under vacuum of at least -0.1 
inches of water (-0.0036 psig or -0.025 kPa gauge). We proposed that 
storage vessels that are vented to a closed vent system must be 
designed to operate at elevated pressures (1 psig above MTVP plus any 
back pressure from the control device) without venting to the 
atmosphere. We are retaining this as an option but are adding an option 
to design and operate the recovery system to prevent venting from the 
storage vessel. In either case, we are retaining requirements 
consistent with those proposed that monitoring systems must be 
installed to detect pressure releases from each pressure relief device 
(PRD) or vacuum breaking device on a storage vessel and each PRD on the 
closed vent system. For owner and operators electing to design the 
storage vessel and closed vent system to operate at elevated pressures, 
we are including provisions that allow the control device to be taken 
out of service for maintenance provided that the storage vessels are 
operated with no emissions to the atmosphere.
    We are retaining requirements for control devices to meet 98 
percent control efficiencies as proposed. We allow enclosed combustion 
devices to demonstrate on-going compliance with the 98 percent control 
efficiency using temperature operating limit, as proposed. However, we 
are also finalizing an alternative for enclosed combustion devices, if 
elected, to comply with the flare operating limits, consistent with 
recent provisions provided for gasoline distribution facilities (40 CFR 
part 60, subpart XXa and 40 CFR part 63, subparts R and BBBBBB). 
Lastly, we are amending the requirements for open-ended lines to align 
with provisions more closely under the Miscellaneous Organic Chemical 
Manufacturing NESHAP (MON).
    Comment: Two commenters suggested that the pressure constraints on 
design operating pressure and vacuum breaking devices are not 
technically feasible and could result in significant damage or failures 
of the storage vessels, stating that a gauge pressure higher than the 
designed pressure of the storage vessel or a vacuum greater than the 
design requirements could result in catastrophic failure of the storage 
vessel. The commenters noted that the proposed requirements conflict 
with American Petroleum Institute (API) Codes 650 and 2000. The 
commenters recommended the EPA delete the specific pressure 
requirements proposed and replace with general language that 
atmospheric vents should be designed to remain closed during normal 
operation.
    Response: In the proposal, we intended to require the use of low-
pressure storage vessels rather than atmospheric storage vessels so 
that the storage vessels would be built to withstand higher pressures. 
However, we recognize that this may be a more significant retrofit for 
modified storage vessels with gas collection systems designed to 
operate at lower pressures such that the pressure in the storage 
vessels can remain near atmospheric pressure. However, if the vapor 
recovery compressor or fan fails or is shut down for any reason, then 
the storage vessel would vent rather than being able to withstand the 
buildup of pressure as the headspace in the storage vessel reaches 
saturation without venting to the atmosphere like a low-pressure 
storage vessel would. We are maintaining the positive pressure 
requirements as one compliance option, but we are also finalizing an 
option for facilities to design and operate a vapor recovery system in 
a manner to prevent atmospheric releases from the storage vessel. As 
proposed, any pressure release from the storage vessel is a deviation 
of the storage vessel and closed vent system requirements. We are 
finalizing monitoring system requirements for the pressure relief 
devices and vacuum breaking devices to identify these deviations.
    With respect to the vacuum requirements, we reviewed the API 650 
standards applicable to low-pressure storage vessels and found in 
section 5.10.5.2 that these storage vessels ``. . . may be safely 
subjected to a partial vacuum in the gas or vapor space not exceeding 1 
ounce per square inch with the operating liquid level in the tank at 
any stage from full to empty.'' One ounce per square inch is equivalent 
to 0.0625 psi or 2 inches of water, so we agree that the vacuum 
requirement proposed is beyond standard design requirements for low-
pressure storage vessels. We also confirmed that the API 650 standard 
indicates that the maximum vacuum for atmospheric storage vessels 
(without needing additional design considerations) is -0.25 kPa (or -1 
inch of water or -0.036 psig). In our proposal, we wanted to ensure 
that the vacuum vent is closed while there is still a slight vacuum in 
the storage vessel, to prevent venting to the atmosphere from the 
vacuum breaking device as the pressure in the storage vessel increases. 
In reviewing the storage vessel specifications, we determined that the 
value we proposed was higher than needed to achieve this objective. The 
vacuum breaking devices must open before the maximum vacuum pressure is 
reached, so typical opening pressures are 0.5 inches of water pressure. 
Therefore, we are finalizing that the vacuum breaking device must close 
while the storage vessel is still under vacuum of at least -0.1 inches 
of water (-0.0036 psig or -0.025 kPa gauge) and are finalizing that a 
pressure release (deviation) occurs when the vessel reaches atmospheric 
pressure and the vacuum breaking device remains open. We are providing 
separate paragraphs for the monitoring requirements for PRDs between 
storage vessels and closed vent systems and adding monitoring 
requirements for the vacuum breaking devices on the storage vessels. 
Otherwise, the separate pressure release monitoring requirements we are 
finalizing in 40 CFR 60.112c(d)(1)(iii) and (d)(2)(iii) are the same as 
proposed for ``each pressure relief device on a storage vessel or in a 
closed vent system,'' in 40 CFR 60.112c(d)(2)(iii).

[[Page 83308]]

    Comment: One commenter recommended that the EPA add a 240-hour 
planned routine maintenance provision for storage vessels equipped with 
a closed vent system routed to a control device to NSPS subparts Kb and 
Kc similar to the language in the part 63 NESHAP regulations such as 
the MON and Organic Liquids Distribution (non-gasoline) NESHAP. 
According to the commenter, if the EPA decides to retain the language 
in 40 CFR 60.110c(g) removing the SSM provisions, it is reasonable for 
the EPA to include a separate 240-hour planned routine maintenance 
provision for control devices in NSPS subpart Kc similar to the 
language in the MON (40 CFR 63.2470(d)) and the associated 
recordkeeping and reporting requirement similar to the language in 40 
CFR 63.998(d)(2) and 63.999(c)(4).
    Response: We disagree that we should provide 240 hours for 
uncontrolled emissions when using an add-on control device. Similar 
provisions are not needed or appropriate for IFRs, which were 
determined to be the BSER for storage vessels storing VOLs with an MTVP 
less than 11.1 psia. We maintain that a 98 percent control requirement 
at all times is necessary for add-on control devices to achieve 
emission reductions equivalent to those for IFRs. Even for storage 
vessels storing VOLs with an MTVP of 11.1 psia or higher, we maintain 
that a 98 percent control requirement is the BSER, and that level of 
control cannot be achieved if we allow 240 hours of uncontrolled 
emissions. Nonetheless, if the storage vessel is designed to be able to 
operate at pressures above the MTVP consistent with the storage vessel 
design pressure requirements proposed (and being finalized as one 
compliance option), then the control device can be isolated from the 
storage vessel, and the closed vent system and the storage vessel can 
remain in service without venting to the atmosphere provided that the 
storage vessel is not filled to the extent that the pressure limits of 
the pressure relief valves on the storage vessel and closed vent system 
are exceeded and there is a pressure release. If there is no pressure 
release from the storage vessel during the planned maintenance 
activity, we agree that planned maintenance can be allowed. Therefore, 
we are including provisions at 40 CFR 60.112c(d)(7) to allow owners or 
operators to conduct planned maintenance on control devices while 
storage vessel affected facilities are still storing VOL under specific 
circumstances. Specifically, the storage vessel(s) storing VOL must be 
designed to operate above the MTVP of the stored VOL according to the 
requirements in 40 CFR 60.112c(d)(1)(i) and must comply with the 
pressure release monitoring, recordkeeping, and reporting requirements. 
Eliminating pressure releases during the maintenance periods may 
require operators to limit VOL addition to the storage vessel (such as 
only adding VOL when there is also corresponding withdrawal of VOL from 
the storage vessel), but the operator is expected to operate the 
storage vessel without a pressure release or atmospheric venting during 
the maintenance period.
    Comment: One commenter stated that the EPA should define ``vapor 
combustion unit'' separately from ``incinerator'' and apply appropriate 
monitoring provisions to vapor combustion units (VCUs) to avoid 
subjecting VCUs to inappropriate requirements. The commenter stated 
that the EPA should allow VCUs to elect to meet the proposed flare 
provisions, as was provided in the Gasoline Distribution rules.
    Response: In general, we agree with the commenter. We note that we 
had proposed specific requirements for ``enclosed combustion devices'' 
so we elected to define that term. We recognize that some enclosed 
combustion devices may operate more like a flare than like an 
incinerator (no direct combustion chamber and no means to control the 
amount of air entering the device). In similar situations in other 
rules (gasoline distribution rules at 40 CFR part 60, subpart XXa, and 
40 CFR part 63, subparts R and BBBBBB, and the oil and gas rule at 40 
CFR part 60, subparts OOOOb and OOOOc), we have allowed the enclosed 
combustion devices to comply with the flare operating limits rather 
than with the temperature operating limit. As such, we agree with the 
commenter's suggestion to allow enclosed combustion devices to comply 
with the flare operating limits. We have added a definition of both 
``enclosed combustion device'' and ``flare'' to help distinguish 
between these devices (enclosed combustion devices emit pollutants 
through a conveyance suitable to conduct a performance test, and flares 
have open or shrouded flames and do not emit pollutants through a 
conveyance suitable to conduct a performance test). We note that the 
implementation of this provision led to revision of several paragraphs 
related to control device operating limits and monitoring, 
recordkeeping, and reporting requirements to allow ``enclosed 
combustion devices electing to comply with Sec.  60.112c(d)(5)'' to be 
treated differently than other non-flare combustion devices. We are 
retaining the requirement for enclosed combustion devices to conduct a 
performance test to demonstrate that the enclosed combustion device is 
achieving a 98 percent VOC emission reduction regardless of whether the 
enclosed combustion device is complying with the flare operating limits 
in 40 CFR 60.112c(d)(5) or the temperature operating limits in 40 CFR 
60.113c(c)(1)(ii)(E).
    Comment: One commenter stated that the EPA should clarify in the 
final NSPS subpart Kc rule, in the closed vent system and bypass line 
provisions, that open-ended valves or lines that use a cap, blind 
flange, plug, or second valve are not considered to be bypass lines. 
According to the commenter, the EPA should add the text that is in 40 
CFR 63.2450(e)(6)(v)(B) of the MON rule to 40 CFR 60.112c(d)(2)(ii) to 
clearly exempt these open-ended valves or lines from the bypass 
requirements.
    Response: We agree with the recommendations to align NSPS subpart 
Kc more closely with the provisions in the MON regarding open-ended 
valves or lines that use a cap, blind flange, plug, or second valve, 
and have revised to 40 CFR 60.112c(d)(2)(ii) accordingly.
6. Control Standards for Degassing
    Based on the analysis presented at proposal, the EPA proposed 
emptying and degassing standards in accordance with the BSER applicable 
to: (1) storage vessels equipped with a closed vent system routed to a 
control device, fuel gas system, or process; and (2) IFR and EFR 
storage vessels that have a capacity of greater than or equal to 1 
million gallons storing a VOL with an MTVP greater than or equal to 1.5 
psia. These vessels must meet certain requirements while the vapors in 
the storage vessel are at or above 10 percent of the LEL. The proposed 
standards of performance for degassing emissions reflect a 98 percent 
VOC reduction efficiency.
    Regarding degassing controls, we are finalizing these provisions 
with minor revisions to what was proposed. We are finalizing standards 
for storage vessels subject to controlling degassing emissions as 
proposed. We are finalizing a requirement that controls must be used 
until the vapor space concentration is less than 10 percent of the LEL, 
as proposed, but we are also finalizing provisions for nonflammable 
liquids to comply with a 5,000 ppmv as methane concentration level 
based on comments received, because 5,000 ppmv is equal to 10 percent 
LEL if the vapors were methane. We are finalizing that the degassing 
emissions that must be controlled must be vented to control

[[Page 83309]]

device that achieves a 98 weight percent VOC reduction or greater as 
proposed. We are finalizing additional provisions to check LEL 
instrument calibration and instrumental offset response each day the 
instrument is used and prior to discontinuing controlled degassing 
consistent with LEL measurement requirements for IFR monitoring to 
ensure the accuracy of the instrument readings. We are also finalizing 
provisions that allow the introduction of chemicals or diluents for the 
purpose of reducing vapor concentration before or during active 
degassing, after considering comments received.
    Comment: Two commenters stated that the EPA should incorporate a 
concentration limit for the storage vessel degassing emissions in 40 
CFR 60.112c(e) since nonflammable chemicals do not exhibit an LEL. The 
commenter requested that the EPA include a concentration limit of less 
than 5,000 ppmv as methane as an alternative to the LEL requirement, 
consistent with the National Emission Standards for Organic Hazardous 
Air Pollutants From the Synthetic Organic Chemical Manufacturing 
Industry proposal.
    Response: We expect that most VOLs with an MTVP above 1.5 psia will 
have some flammability, but we agree that a concentration limit of 
5,000 ppmv as methane for nonflammable liquids is appropriate because 
5,000 ppmv is the 10 percent LEL of methane and it generally provides a 
concentration value that is similar to or lower than the 10 percent LEL 
level for heavier organics. For example, 10 percent LEL of butane is as 
stringent as or more stringent than 1,900 ppmv as butane or about 7,600 
ppmv as methane.
    Comment: One commenter noted that some companies flood the bottom 
of the tank with a low vapor pressure material to facilitate removal of 
residual sludges and/or to reduce the concentration of vapors in the 
vapor space of the tank prior to or during active degassing. According 
to the commenter, while the proposed rule language does not prohibit 
bottom flushing, this practice should be expressly accommodated in the 
rule language.
    Response: We agree that flooding the bottom of the tank with a low 
vapor pressure material is a reasonable control measure for degassing. 
As such, we are revising 40 CFR 60.112c(e)(1) to expressly allow the 
addition of chemical or a diluent for the purpose of reducing vapor 
concentration before or during active degassing.
7. Alternative Means of Emission Limitation
    We are finalizing the alternative means of emissions limitation 
(AMEL) provisions as proposed except for the addition of two 
clarifications. First, at 40 CFR 60.114c(a), we are replacing ``any'' 
with ``the applicable'' when referencing requirements in 40 CFR 
60.112c, to clarify that the equivalency must be made for the same type 
of control system (IFR, EFR, or closed vent system routed to a control 
device, fuel gas system, or process). This clarification prevents 
operators that are using an IFR from reducing the fitting control 
requirements finalized for an IFR because, for that size of storage 
vessel and stored VOL, the required IFR controls achieve greater than a 
98 percent reduction or greater reduction than an EFR meeting the final 
EFR requirements. Second, we are clarifying that the written 
application to the Administrator in 40 CFR 60.114c(c) may include 
either actual emissions test results or an engineering evaluation that 
the Administrator determines to be accurate, but it does not 
necessarily have to include both.
    Comment: One commenter noted the proposed NSPS subpart Kc provides 
for requesting an AMEL at 40 CFR 60.114c and this section specifies 
that a request for approval of an alternative must include an actual 
emissions test; however, there are numerous alternative control 
measures that have already been tested and for which the EPA has 
published emission factors in AP-42. The commenter stated that the EPA 
should not arbitrarily require repeated testing for those control 
measures that have already been tested and for which the results have 
already been accepted by the EPA. The commenter stated that the 
language in 40 CFR 60.114c should be replaced with the language in 
NESHAP subpart WW at 40 CFR 63.1064.
    Response: We have revised 40 CFR 60.114c(c) such that an AMEL 
written application must include either an actual emissions test (that 
covers the appropriate range of meteorological conditions) or an 
engineering evaluation, which may include use of emission factors as 
published in the EPA Report No. AP-42, Compilation of Air Pollutant 
Emission Factors. We reviewed the AMEL provision in NESHAP subpart WW. 
The NESHAP subpart WW provisions include a listing of test methods but 
do not limit the testing to those methods. As such, we are determining 
that the language that is included in the final rule is equivalent to 
the provisions in NESHAP subpart WW. We also note that the provisions 
in 40 CFR 63.1064(c) allow the use of different combinations of rim and 
deck fitting controls ``. . . if the alternate emits no more than the 
combination specified in the Sec.  63.1063.'' We interpret this 
provision to allow comparisons of fitting controls for IFRs to those 
required specifically for IFRs. While we consider that the three 
control options we provided are equivalent, we acknowledge that, 
depending on the size of tank, volatility of the VOL, and prevailing 
meteorological conditions, one of the control configurations (IFR, EFR, 
or closed vent system routed to a control device, fuel gas system, or 
process) will perform better and one configuration will perform worse 
than the other options allowed. We did not intend to allow changes to 
the specified control provisions to only require the lowest control 
efficiency for a given combination of tank size, VOL stored, and 
meteorological conditions. Therefore, we are also clarifying, 
consistent with our interpretation of the NESHAP subpart WW provisions, 
that the AMEL must compare with the ``applicable'' requirement. That 
is, for storage vessels with IFRs, you may request an AMEL for a 
different set of fittings, but you must show equivalency with the IFR 
requirements specified in 40 CFR 60.112c(b). For storage vessels with 
EFRs, the AMEL must show equivalency with the EFR requirements 
specified in 40 CFR 60.112c(c). For storage vessels with a closed vent 
system routed to a control device, fuel gas system, or process, the 
AMEL must show equivalency with the control requirements specified in 
40 CFR 60.112c(d). With these revisions, we determine that the final 
AMEL provisions in NSPS subpart Kc are consistent with the AMEL 
provisions in NESHAP subpart WW.
    Since control measures that were determined to be equivalent to 
NSPS subpart Kb may not be equivalent to controls required under NSPS 
subpart Kc, a new AMEL application must be submitted following 40 CFR 
60.114c(c) in order to demonstrate that an AMEL is equivalent to the 
requirements in NSPS subpart Kc.

C. NSPS Subpart Kc Without Startup, Shutdown, and Malfunction 
Exemptions

    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. 
We are finalizing in NSPS subpart Kc specific requirements at 40 CFR 
60.110c(g) that override the general provisions for SSM requirements. 
In finalizing the standards in this rule, the EPA has considered

[[Page 83310]]

startup and shutdown periods and, for the reasons explained in this 
section of the preamble, has not finalized alternate standards for 
those periods. The EPA has determined that the reasoning in the court's 
decision in Sierra Club applies equally to CAA section 111 because the 
definition of ``emission standard'' in CAA section 302(k), and the 
embedded requirement for continuous standards, also applies to the 
NSPS.
    Periods of startup, normal operations, and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead, they are, by 
definition, sudden, infrequent, and not reasonably preventable failures 
of emissions control, process, or monitoring equipment (40 CFR 60.2). 
The EPA interprets CAA section 111 as not requiring emissions that 
occur during periods of malfunction to be factored into development of 
CAA section 111 standards. Nothing in CAA section 111 or in caselaw 
requires that the EPA consider malfunctions when determining what 
standards of performance reflect the degree of emission limitation 
achievable through ``the application of the best system of emission 
reduction'' that the EPA determines is adequately demonstrated. While 
the EPA accounts for variability in setting emissions standards, 
nothing in CAA section 111 requires the Agency to consider malfunctions 
as part of that analysis. The EPA is not required to treat a 
malfunction in the same manner as the type of variation in performance 
that occurs during routine operations of a source. A malfunction is a 
failure of the source to perform in a ``normal or usual manner,'' and 
no statutory language compels the EPA to consider such events in 
setting CAA section 111 standards of performance. The EPA's approach to 
malfunctions in the analogous circumstances (setting ``achievable'' 
standards under CAA section 112) has been upheld as reasonable by the 
D.C. Circuit in U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016).

D. Testing, Monitoring, and Inspection Requirements

    Because the NSPS reflect the BSER under conditions of proper 
operation and maintenance, we also, in performing our review, evaluate 
and determine the proper testing, monitoring, inspection, 
recordkeeping, and reporting requirements needed to ensure compliance 
with the emission standards. This section of the preamble includes our 
discussion of the proposed revisions to testing, monitoring, and 
inspection requirements, a summary of the significant comments 
received, our responses to the comments, and our final determinations 
regarding testing, monitoring, and inspection requirements. Changes to 
recordkeeping and reporting requirements are included in the section 
for recordkeeping and electronic reporting.
    Generally, we proposed testing, monitoring, and inspection 
requirements consistent with those in NSPS subpart Kb and other Federal 
standards that would provide the best clarity for the specific 
requirements along with the following enhancements. The EPA proposed 
annual LEL monitoring as an enhancement to the monitoring and 
inspection requirements for storage vessels with IFRs. The EPA also 
proposed equipping floating roof storage vessels with a visual or 
audible alarm system to monitor when the floating roof approaches 
specified landing heights. For closed vent systems, the EPA proposed 
quarterly AVO inspections, annual EPA Method 21 instrument monitoring, 
and monitoring of bypasses. The EPA also proposed that storage vessels 
using closed vent systems routed to control devices, fuel gas systems, 
or processes must equip pressure relief devices with appropriate 
monitoring to identify releases. For storage vessels with closed vent 
systems routed to a control device, the EPA proposed that performance 
tests must be conducted at least once every 60 months rather than rely 
on a single initial performance test. Finally, the EPA proposed 
enhanced monitoring requirements for flares consistent with the 
Refinery NESHAP (40 CFR 63.671).
    We are finalizing testing, monitoring, and inspection requirements 
as proposed except for the revisions outlined here.
    <bullet> We revised the specification of the timing of these 
requirements to be ``calendar months'' rather than just ``months,'' to 
clarify the timing and allow limited flexibility when scheduling the 
required testing or inspections.
    <bullet> For IFRs, we are amending the requirements to conduct 
internal inspections of the floating roof at least once every 120 
calendar months. We are retaining this inspection requirement each time 
the vessel is emptied and degassed, but we are not requiring storage 
vessels to be taken out of service specifically to conduct this 
inspection.
    <bullet> We are making minor revisions to the LEL monitoring 
calibration procedures. We proposed language used from the gasoline 
distribution rule (40 CFR part 63, subpart R), which would require the 
correction factor to be based on ``gasoline vapor.'' Because NSPS 
subpart Kc is applicable to a much broader range of chemicals, we are 
revising references to ``gasoline vapors'' to ``vapors of the stored 
VOL.'' We are retaining the use of butane as the surrogate if 
correction factors are not available for the vapors of the VOL stored.
    <bullet> We are adding specific requirements that fittings on EFR 
must be visually inspected during annual seal gap measurement 
inspections to ensure that covers are closed and gasketed with no 
visible gaps and that there are no tears in sleeves, wipers, or similar 
controls used for a given fitting during annual seal gap measurement 
inspections. Visual fitting inspections were proposed at 40 CFR 
60.113c(b)(7) for inspections conducted when the storage vessel is 
emptied and degassed but did not specify fitting conditions that would 
result in an inspection failure, and we are adding these details to 
clarify the fitting inspection requirements based on comments received.
    <bullet> For closed vent systems, we are including an additional 
reference at 40 CFR 60.113c(c)(2) for the quarterly AVO monitoring as 
required under both the proposed and final requirements at 40 CFR 
60.112c(d)(2)(i). We are also revising the provision of 40 CFR 
60.113c(c)(3) to clarify that emissions detected using visible, 
audible, and olfactory methods are leaks triggering corrective action.
    <bullet> Regarding MTVP test methods, we are clarifying that owners 
and operators must determine the MTVP of the VOL prior to refilling the 
storage vessel with a new VOL. The proposed language only referenced 
``initial filling'' and may allow facilities to change VOL without 
reassessing the MTVP. However, we considered that, when a new VOL is 
stored, that would be an initial filling of that VOL. The rephrasing of 
that provision helps to clarify this requirement. Additionally, we are 
adding a requirement to use a vapor-to-liquid ratio of 4:1 when using 
American Society for Testing and Materials (ASTM) D6378-22. We proposed 
this requirement when using ASTM D6377-20 but consider that the same 
provision should apply to both of the MTVP test methods. The EPA's 
intention to use a vapor-to-liquid ratio of 4:1 when using ASTM D6378-
22 was detailed in the proposal preamble but was erroneously omitted 
from the proposed rule text.
    <bullet> Additionally, as noted in section IV.B.5. of this 
preamble, we are allowing enclosed combustion devices to comply with 
the monitoring provisions for flares as an alternative to the 
temperature monitoring requirement.

[[Page 83311]]

    Comment: One commenter stated that the EPA's proposed monitoring 
and inspection requirements for floating roof tanks are inadequate and 
must be strengthened to make it more likely that the tanks can reduce 
98 percent of VOCs. According to the commenter, at a minimum, the EPA 
must require monitoring and inspection in keeping with the current 
requirements from South Coast Air Quality Management District (SCAQMD) 
Rule 1178. In addition, the commenter stated that the EPA must make it 
explicit that, for IFR visual inspections, the entire perimeter of the 
floating roof seal must be visually evaluated, even if that requires 
opening multiple manways. The commenter stated that the EPA must also 
require quarterly forward-looking infrared measurements from tank 
decks.
    Response: In general, we considered that we had incorporated much 
from the SCAQMD Rule 1178 monitoring provisions in our proposal. We 
included LEL monitoring provisions for IFR storage vessels and PRD 
monitoring provisions for storage vessels with closed vent systems 
routed to a control device, fuel gas system, or process that are 
reasonably consistent with the monitoring requirements in SCAQMD Rule 
1178. However, upon further review of SCAQMD Rule 1178 and our proposed 
inspection requirements, we noted that the inspection requirements we 
proposed for EFR storage vessels only covered inspections of the 
primary and secondary seals. Visual fitting inspections were proposed 
for IFR inspections and mentioned in the proposed inspections at 40 CFR 
60.113c(b)(7) when the storage vessel is emptied and degassed. However, 
no requirement for fitting inspections were proposed during annual gap 
measurements, and the inspections proposed at 40 CFR 60.113c(b)(7) did 
not specify fitting conditions that would result in an inspection 
failure. After our review of SCAQMD Rule 1178 monitoring and inspection 
requirements based on this comment, we are adding specific requirements 
that fittings on EFR must be visually inspected during annual seal gap 
measurement inspections to ensure that covers are closed and gasketed 
with no visible gaps and that there are no tears in sleeves, wipers, or 
similar controls used for a given fitting. We are also adding the 
conditions under which an inspection failure occurs for the inspections 
conducted when the EFR storage vessel is emptied and degassed.
    We considered optical gas imaging requirements in previous reviews 
of storage vessels, which we reviewed again for NSPS subpart Kc, and 
concluded that these requirements were not cost-effective. Regarding 
manways, we agree with the commenter's assertion that while performing 
IFR visual inspections, the entire perimeter of the floating roof seal 
must be visually evaluated, even if that requires opening multiple 
manways. We have elected not to add specific rule language, because we 
believe that having visual access to the entire primary seal, is 
already a necessary component of annual IFR inspections both in the 
rule language of NSPS subpart Kc and in the existing rule language of 
NSPS subpart Kb. As such, except for the specifications for fitting 
inspections for EFR storage vessels, we are not adding additional 
monitoring requirements to NSPS subpart Kc.
    Comment: Numerous commenters requested that the EPA allow in-
service inspections of IFRs either by providing additional language in 
40 CFR 60.113c(a)(2) allowing for top-side inspections when there is 
visual access to all deck components or by incorporating an alternate 
means of compliance option to comply with NESHAP subpart WW [40 CFR 
63.1063(d)(1) and (2)]. The commenters noted that in-service 
inspections were allowed in NSPS subpart Kb to avoid the costs and 
emissions associated with emptying and degassing vessels for 
inspection. If in-service inspections are provided, the commenters 
noted, rule revisions may also be needed in the notification 
requirements at 40 CFR 60.116c(b)(1) and the reporting requirements at 
40 CFR 60.116c(c)(2)(ii).
    Response: We had proposed language consistent with NSPS subpart Kb 
at 40 CFR 60.113b(a)(4) to require more detailed ``out of service'' 
inspections at least once every 10 years. The EPA agrees with the 
commenter's request to allow for in-service inspections to be performed 
entirely from the top side of the floating roof. The EPA is 
incorporating language into 40 CFR 60.113c(a)(2)(ii) to allow for in-
service inspections to be performed entirely from the top side of the 
floating roof, as long as there is visual access to all deck fittings 
and rim seal systems specified in 40 CFR 60.112c(b). We are also adding 
repair timelines in 40 CFR 60.112c(b), similar to those already 
established for the annual visual inspection. We are also specifying 
that a 30-day notification must be provided for inspections in 40 CFR 
60.116c(b)(1). Also, we are deleting the phrase ``emptied and degassed 
and'' from 40 CFR 60.116c(c)(2)(iii) to account for the reporting of 
these in-service inspections.
    Comment: One commenter stated that the calibration requirements for 
the LEL meter in 40 CFR 60.113c(a)(3)(ii) and (iv) that are specified 
for demonstrating compliance with the 25 percent LEL limit for IFR 
storage vessels are burdensome and should be simplified to be 
consistent with the calibration requirements for the LEL meter within 
the storage vessel degassing requirements in 40 CFR 60.112c(e). The 
commenter stated that following the procedures for ``calibration and 
maintenance according to manufacturer's specifications'' should be 
adequate for both sections of the rule. The commenter recommended that 
the EPA simplify the language in 40 CFR 60.113c(a)(3)(ii) and (iv) 
consistent with the LEL calibration requirements in the storage vessel 
degassing section. Another commenter noted that the language at 40 CFR 
60.113c(a)(3)(iv) references gasoline vapors and should be generalized 
to accommodate other stored VOLs.
    Response: We disagree that the LEL calibration requirements in 40 
CFR 60.113c(a)(3)(ii) and (iv) are burdensome. These paragraphs allow 
the use of manufacturers' calibration methods, and they primarily 
specify when calibration checks must be made and specify the LEL span 
response. Upon review of the two LEL monitoring requirements, we are 
adding more specific calibration requirements for the LEL monitoring 
instrument used to monitor degassing. Specifically, we are requiring 
calibration and zero offset checks each day and at the end of the 
degassing event prior to completion to confirm that the final readings 
are accurate before controlled degassing can be discontinued.
    With respect to the comment regarding the reference to gasoline 
vapors in the calibration requirements at 40 CFR 60.113c(a)(3)(iv), we 
agree that the proposed language needed to be generalized. We used 
calibration language from the gasoline distribution rule (40 CFR part 
63, subpart R), which requires the correction factor to be based on 
``gasoline vapor.'' Because NSPS subpart Kc is applicable to a much 
broader range of chemicals, we are revising references to ``gasoline 
vapors'' to ``vapors of the stored VOL.'' We are, however, retaining 
the use of butane as the surrogate if correction factors are not 
available for the vapors of the VOL stored, because a surrogate is 
needed when no published correction factor is available for the VOL, 
and butane is considered a reasonable surrogate for any VOL that does 
not have a published correction factor.
    Comment: Two commenters stated that EPA Method 21 testing is 
laborious, costly, and time-consuming for

[[Page 83312]]

facilities. One commenter believes that the sensory monitoring 
provisions as proposed would place undue burdens on operators and would 
result in redundancy in monitoring and compliance measures. Both 
commenters stated that when coupled with the quarterly sensory testing, 
the requirement for annual EPA Method 21 testing is unnecessary. One 
commenter submitted a 1997 rule interpretation memorandum written by 
the Texas Natural Resource Conservation Commission, which explained 
that the EPA Method 21 test under NSPS subpart Kb is not considered a 
performance test under 40 CFR 60.8 since the EPA Method 21 is 
considered a screening measurement rather than a performance test, 
subject to the recordkeeping requirements in the General Provisions of 
40 CFR 60.7(f) and not required to be reported by either NSPS subpart A 
or Kb. The commenter requested that the EPA discuss whether the EPA 
agrees or disagrees with this guidance and whether the interpretation 
also applies to NSPS subpart Kc.
    Response: We disagree that quarterly AVO monitoring is burdensome. 
If a leak is found via AVO monitoring, it triggers corrective action. 
Additionally, we disagree that annual EPA Method 21 monitoring is 
unnecessary, because EPA Method 21 will detect small emissions sources 
that are above 500 ppm but that would remain undetected by AVO 
monitoring. The closed vent system is to be operated ``with no 
detectable emissions as indicated by an instrument reading of less than 
500 ppm above background and visual inspections, as determined in part 
60, subpart VV, Sec.  60.485(b).'' In the case of NSPS subpart Kb, 40 
CFR 60.113b(c) states: ``The owner or operator of each source that is 
equipped with a closed vent system and control device as required in 
Sec.  60.112b (a)(3) or (b)(2) (other than a flare) is exempt from 
Sec.  60.8 of the General Provisions and shall meet the following 
requirements.'' As such, the language in NSPS subpart Kb indicates that 
40 CFR 60.8 does not apply.
    For NSPS subpart Kc, we used language that the closed vent system 
must operate ``. . . with no detectable emissions as indicated by an 
instrument reading of less than 500 ppmv above background . . .'' (see 
40 CFR 60.112c(d)(2)), but there is no clear exemption from 40 CFR 60.8 
in 40 CFR 60.113c(c)(2). Nonetheless, we agree that the requirements in 
40 CFR 60.8 do not apply to EPA Method 21 instrument monitoring under 
NSPS subpart Kb. Unlike in NSPS subpart Kb, we proposed and are 
finalizing reporting requirements in NSPS subpart Kc for EPA Method 21 
instrument monitoring events. In reviewing the proposed NSPS subpart Kc 
provisions related to EPA Method 21 and AVO monitoring, we recognized 
that we focused on the instrument monitoring requirements when using 
EPA Method 21 and inadvertently neglected to mention the AVO inspection 
requirements. Therefore, we are adding reference to the monthly AVO 
monitoring requirement in 40 CFR 60.113c(c)(2) consistent with the 
requirement under the proposed and final requirements at 40 CFR 
60.112c(d)(2)(i), and we are revising the provision of 40 CFR 
60.113c(c)(3) to clarify that emissions detected using AVO methods are 
``leaks'' triggering corrective action. This latter revision also 
clarifies that leaks identified from AVO monitoring do not trigger the 
need to conduct EPA Method 21 monitoring of an AVO-identified leak. In 
our review, we also identified a lack of reporting requirements related 
to AVO-identified leaks. Therefore, we have also revised what we 
proposed for recordkeeping requirements at 40 CFR 60.115c(d)(3)(v) and 
reporting requirements at 40 CFR 60.116c(f)(8)(ii) to indicate the type 
of monitoring conducted and to report information regarding all leaks 
identified, not just those identified during EPA Method 21 instrument 
monitoring.
    Comment: Several commenters requested revisions to the vapor 
pressure testing requirements for mixtures of indeterminate or variable 
composition to define the term ``variable'' and to not require the 
initial and repeat physical testing for liquids whose upper and lower 
bounds of vapor pressure are known or are readily calculated using 
standard reference texts and good engineering judgment.
    Response: We agree with the commenters that the concept of 
``variable compositions'' of stored liquid mixtures for which the 
proposed rule would require initial and repeat physical testing to 
determine MTVP could be applied more broadly than intended. Thus, in 40 
CFR 60.113c(d)(1) of the final rule, we are clarifying that for 
mixtures of variable composition, if the range of concentrations for 
each constituent is known such that the MTVP can be determined from 
data and procedures in standard reference texts, then physical testing 
is not required. Similarly, under the final rule, physical testing is 
not required for crude oils and refined petroleum products for which 
Reid vapor pressure is known and MTVP can be determined from nomographs 
and other procedures described in reference texts such as AP-42. 
Additionally, in 40 CFR 60.113c(d)(2) we have clarified that the 
provisions apply to affected storage vessels storing a mixture of 
indeterminate composition or a mixture of unknown variable composition.

E. Recordkeeping and Electronic Reporting

    The EPA is finalizing a requirement that owners and operators of 
new, modified, or reconstructed VOL storage vessels subject to NSPS 
subpart Kc maintain records of the results of required testing, 
monitoring, and inspections. The EPA is finalizing a requirement that 
owners and operators of VOL storage vessels subject to the current and 
new NSPS at 40 CFR part 60, subparts Kb and Kc, submit electronic 
copies of required performance test reports and the semiannual excess 
emissions and continuous monitoring system performance and summary 
reports, through the EPA's Central Data Exchange (CDX) using the 
Compliance and Emissions Data Reporting Interface (CEDRI).
    We are finalizing the recordkeeping and reporting requirements 
similar to those proposed except that some of the revisions made to the 
standards, testing, and monitoring provisions required revision of the 
recordkeeping and reporting requirements for the final rule. The 
revisions to the proposed recordkeeping and reporting requirements and 
our rationale for making the revisions are summarized in this section.
    <bullet> As noted in section IV.D. of this preamble, we are 
revising the recordkeeping and reporting requirements in 40 CFR 
60.115c(d)(3)(v) and 60.116c(c)(8)(ii) to include the type of 
monitoring conducted and to report information regarding all leaks 
identified, including leaks identified using AVO methods.
    <bullet> As noted in section IV.B.5. of this preamble, we separated 
PRD monitoring requirements to separately address devices on storage 
vessels and devices on the closed vent system and included provisions 
to monitor vacuum breaking devices on storage vessels. In reviewing 
recordkeeping and reporting requirements related to these provisions, 
we noted that we had proposed reporting requirements for PRDs, but we 
failed to include recordkeeping requirements for PRDs. Therefore, we 
are adding recordkeeping requirements at 40 CFR 60.115c(d)(3)(vii) for 
PRDs or vacuum breaking devices on a storage vessel or closed vent 
system that include: the device type; the monitoring device or system 
used for the device; data from

[[Page 83313]]

the device or system indicating whether a pressure release occurred; 
and the date, time, and duration of each pressure release, if 
applicable. We are also adding reporting requirements at 40 CFR 
60.116c(c)(12) for each pressure release that occurred as a result of a 
vacuum breaking device that failed to close prior to the storage vessel 
reaching atmospheric pressure. The added reporting requirements 
include: identification of the vacuum breaking device; start date, 
start time, and duration (in minutes) of the pressure release; and an 
estimate of the mass quantity in pounds of VOL released. These 
requirements mimic the pressure release reporting requirements proposed 
(and being finalized) for PRDs, and these similar reporting 
requirements are needed to document compliance with or deviations from 
the requirements for vacuum breaking devices used for storage vessels 
using a closed vent system routed to a control device.
    <bullet> As noted in section IV.B.5. of this preamble, we are 
including alternative provisions that allow enclosed combustion devices 
to comply with the flare operating and monitoring requirements. We 
include minor revisions to the proposed recordkeeping and reporting 
requirements commensurate with the provided alternative, to specify 
which recordkeeping and reporting requirements apply to control systems 
``other than flares or enclosed combustion devices electing to comply 
with Sec.  60.112c(d)(5)'' and which recordkeeping and reporting 
requirements apply to ``flares or enclosed combustion devices electing 
to comply with Sec.  60.112c(d)(5).'' We are also adding a reporting 
requirement for the initial notification at 40 CFR 60.116c(a)(6) that 
includes a requirement to specify the type of control device used and 
the compliance option selected, which, if an enclosed combustion device 
is used, include whether the device is complying with a temperature 
operating limit or is instead electing to comply with the flare 
requirements in 40 CFR 60.112c(d)(5). This initial notification 
requirement will be useful for EPA permitting and enforcement personnel 
to clearly understand the compliance option being elected for the 
enclosed combustion device.
    <bullet> For EFRs, as discussed in section IV.D. of this preamble, 
we added requirements to visually inspect the roof fittings (such as 
access hatches, gauge floats, gauge hatch/sample wells, rim vents, deck 
drains, deck legs, vacuum breakers, pontoon covers, and guidepoles) 
when gap measurements are conducted. We are adding to the list at 40 
CFR 60.116c(c)(5)(vi)(A) to include reference to deviations of the 
fitting controls outlined in 40 CFR 60.113c(b)(4)(iii)(A) through (D) 
to allow reporting of fitting deviations identified during the gap 
measurement inspections.
    <bullet> As discussed in the comment and response included in this 
section of the preamble, we are revising what we proposed for the 
timing of semiannual compliance reports to either cover fixed time 
periods (from January 1 to June 30 or July 1 to December 31) or align 
with established reporting dates based on 40 CFR parts 70 or 71 permit 
requirements. The proposed schedule for semiannual reports appeared to 
require separate semiannual reports for different affected storage 
vessels at a facility depending on when the storage vessel became 
affected under NSPS subpart Kc. Because facilities may have several 
affected storage vessels under NSPS subpart Kc, having fixed reporting 
periods simplifies the reporting requirements for these facilities.
    Comment: Numerous commenters requested that the EPA revise NSPS 
subpart Kc so that reporting requirements are consistent with other 
reporting obligations and establish the same semiannual reporting 
deadline for all VOL storage vessels. The commenters noted that, as 
proposed, it appeared that each affected VOL storage vessel could have 
a separate reporting schedule depending on when the sources became 
affected sources under NSPS subpart Kc. The commenters recommended that 
the EPA require the annual reports to cover activities in set time 
periods (January 1 through June 30 or July 1 through December 31, as 
applicable). One commenter also recommended that the EPA include an 
alternative that would allow each affected facility subject to 
permitting regulations pursuant to 40 CFR parts 70 or 71 to align the 
semiannual reports with established dates for submitting semiannual 
reports pursuant to 40 CFR 70.6(a)(3)(iii)(A) or 40 CFR 
71.6(a)(3)(iii)(A).
    Response: First, we never intended to have different semiannual 
compliance report schedules for different storage vessels at a given 
facility. We note that the reporting form template was designed to 
allow reporting of all storage vessels at the facility in one 
semiannual report. However, we agree that, because the affected 
facility is each VOL storage vessel, the proposed requirements at 40 
CFR 60.116c(d) could be interpreted to impose different reporting 
schedules for different storage vessels if they become affected 
facilities in different months. Several commenters suggested that the 
semiannual reports cover fixed timeframes, specifically January through 
June and July through December. This appears reasonable. One commenter 
also suggested including reference to semiannual reports under 40 CFR 
parts 70 or 71 in the event that the current semiannual reporting 
period is different from January through June and July through 
December. This also appears reasonable. Therefore, we are providing a 
fixed timeframe for the semiannual reports (January through June and 
July through December) and providing an alternative timeframe to 
harmonize with other semiannual reports as scheduled under 40 CFR parts 
70 or 71, if different from the fixed timeframe being finalized. We 
clarify that the first semiannual compliance report is triggered by the 
date on which the first storage vessel at the facility becomes an 
affected facility subject to NSPS subpart Kc and would cover, for 
example, April 15 through June 30 if the source becomes an affected 
facility on April 15. As new storage vessels become affected facilities 
under NSPS subpart Kc, the information for those storage vessels will 
be added to the semiannual report. These semiannual reporting 
requirements simplify the reporting requirements compared to the timing 
proposed and allow alignment of the semiannual reports provided for 
NSPS subpart Kc with other reporting requirements that may apply for 
the facility.

F. Other Final Amendments

1. Editorial Corrections
    We received a number of comments regarding editorial, 
typographical, and cross-reference corrections that we agree with and 
are finalizing. Additionally, we received comments recommending 
clarification of requirement language to reduce misinterpretation. 
After reviewing these comments, we are revising some language in the 
final rule. We are revising references of ``a control'' to ``a control 
device.'' Beyond these changes, the EPA made several revisions 
throughout NSPS subpart Kc to improve clarity.
    One commenter recommended that the EPA clarify in 40 CFR 
60.113c(d)(1) that the requirement to determine MTVP is not a one-time 
requirement, as implied by the word ``initial,'' but also applies to 
non-anticipated tank service changes. We agree that if the VOL stored 
in the storage vessel changes, the MTVP should be reassessed. We are 
revising 40 CFR 60.113c(d)(1) to require that this determination be 
made prior to the

[[Page 83314]]

initial filling of the storage vessel or to the refilling of the 
storage vessel with a new VOL.
    One commenter recommended that in 40 CFR 60.115c(d)(5)(i) and 40 
CFR 60.116c(c)(10)(i)(A) the EPA should add ``or flare flame'' to any 
occurrence of ``pilot flame'' consistent with the provisions in 40 CFR 
60.112c(d)(5)(iv) and 40 CFR 60.113c(c)(1)(iv)(B). We are revising 40 
CFR 60.115c(d)(5)(i) and 40 CFR 60.116c(c)(10)(i)(A) accordingly.
2. Definitions
    We received several comments recommending the inclusion of 
definitions that were not included in the proposal. Additionally, we 
received comments recommending definition revisions. This section of 
the preamble summarizes major comments received concerning definitions 
and provides our responses to those comments.
    Comment: Several commenters recommended that the EPA define the 
term ``pressure relief device'' in NSPS subpart Kc and provided a 
suggested definition:

    Pressure relief device means a valve, rupture disk, or similar 
device used only to release an unplanned, nonroutine discharge of 
gas from process equipment in order to avoid safety hazards or 
equipment damage. A pressure relief device discharge can result from 
an operator error, a malfunction such as a power failure or 
equipment failure, or other unexpected cause. Such devices include 
conventional, spring-actuated relief valves, balanced bellows relief 
valves, pilot-operated relief valves, rupture disks, and breaking, 
buckling, or shearing pin devices. Devices that are actuated either 
by a pressure of less than or equal to 2.5 pounds per square inch 
gauge or by a vacuum are not pressure relief devices.

    Response: We agree with the commenters and are including a 
definition of ``pressure relief device'' in NSPS subpart Kc similar to 
the commenters' suggestion. For storage vessels, we consider 
``conservation vents'' to be PRDs. These conservation vents typically 
have actuation pressure less than 2.5 psig. As such, the last sentence 
in our final definition reflects a change from the last sentence in our 
proposed definition to only exclude vacuum breaking devices from the 
definition of ``pressure relief devices.'' We are also clarifying that, 
if a device has both a pressure relief function and a vacuum breaking 
function, such as a conservation vent, the portion of the conservation 
vent that acts to relieve pressure is considered a PRD and the portion 
of the conservation vent that acts to relieve vacuum is a vacuum 
breaking device and not a PRD. We are also adding a definition of 
``vacuum breaking device,'' which is specific to the fixed roof portion 
of the storage vessel and a vacuum breaker which is a component of a 
floating roof.
    Comment: One commenter recommended that the EPA define the term 
``pressure release.''
    Response: We are adding a definition of ``pressure release'' to 40 
CFR 60.111c. We are including in the definition of ``pressure release'' 
emissions of materials resulting from a vacuum breaking device failing 
to close prior to the system reaching atmospheric pressure.
    Comment: One commenter recommended that the EPA define the terms 
``vapor balancing system,'' ``fuel gas,'' ``fuel gas system,'' and 
``routed to a process or route to a process.''
    Response: We determined that vapor balancing is not appropriate or 
equivalent to the BSER identified for VOL storage vessels. As such, we 
are not including a definition of ``vapor balancing system'' in NSPS 
subpart Kc. We disagree with the commenter's request to define ``fuel 
gas'' because the ``fuel gas system'' definition is sufficient. We are 
finalizing definitions for ``fuel gas system'' and ``routed to a 
process or route to a process'' in NSPS subpart Kc.
    Comment: One commenter recommended that the EPA define 
``degassing'' with language consistent with the Texas Commission on 
Environmental Quality's (TCEQ) definition.
    Response: The EPA agrees with the commenter to define 
``degassing''; however, the TCEQ definition is insufficient as there 
may be other reasons to empty and degas a storage vessel other than 
cleaning. While we agree that cleaning may be a step in the process, we 
expect degassing to occur for other reasons. We are finalizing a 
definition for ``degassing'' in NSPS subpart Kc to clarify this point.

G. Effective Date and Compliance Dates

    Pursuant to CAA section 111(b)(1)(B), the effective date of the 
final rule requirements in subpart Kc will be the promulgation date. 
Affected sources that commence construction, reconstruction, or 
modification after October 4, 2023, must comply with all requirements 
of subpart Kc no later than the effective date of the final rule or 
upon startup, whichever is later. The EPA is finalizing amendments to 
NSPS subpart Kb to include electronic submission requirements. Affected 
NSPS subpart Kb sources that commence construction, reconstruction, or 
modification after July 23, 1984, and before October 4, 2023, must 
comply with the updated requirements to submit reports electronically 
no later than the effective date of the final rule.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the air quality impacts?

    The final provisions in NSPS subpart Kc reduce emissions of VOCs, 
some of which may also be hazardous air pollutants (HAPs). The EPA 
estimates that the final standards will reduce VOC emissions by 1,085 
tons per year, which includes the impacts from new, modified, and 
reconstructed storage vessels. More information regarding the air 
quality impacts and emission reductions are included in the memorandum 
Control Options for Storage Vessels (Docket ID No. EPA-HQ-OAR-2023-
0358-0002).

B. What are the cost impacts?

    This final action will cost (in 2022 dollars) approximately $21.1 
million in total capital cost and result in a total annualized cost of 
$5.38 million per year (including product recovery) based on our 
analysis of the final actions in NSPS subpart Kc. More information 
about the estimated cost of the final actions can be found in the 
memorandum Control Options for Storage Vessels (Docket ID No. EPA-HQ-
OAR-2023-0358-0002).

C. What are the economic impacts?

    For economic impact analyses (EIA) of rules that directly affect a 
single industry or a few industries, the EPA often prepares a partial 
equilibrium analysis. In this type of economic analysis, the focus of 
the effort is on estimating impacts on a single affected industry or 
several affected industries, and all impacts of this rule on industries 
outside of those affected are assumed to be zero or so inconsequential 
as to not be considered in the analysis. If the compliance costs, which 
are key inputs to an EIA, are quite insignificant, then the impact 
analysis could consist of a calculation of annual (or annualized) costs 
as a percentage of sales for affected companies. This latter type of 
analysis is called a screening analysis and is applied when a partial 
equilibrium or more complex EIA approach is deemed not necessary given 
the expected size of the impacts.
    The net present value of the estimated cost impacts of NSPS subpart 
Kc is $19.4 million, discounted at a 3 percent rate over a 5-year 
analytic timeframe from 2024 to 2028 in 2022 dollars. Using a 7 percent 
discount rate, the net present value of the estimated cost impacts is 
$17.3 million. The equivalent annualized value in 2022 dollars is a

[[Page 83315]]

cost of approximately $4.1 million using a discount rate of either 3 or 
7 percent.
    Storage vessels in NSPS subpart Kb are most closely associated with 
the petroleum and coal products industry (NAICS 324000), the chemical 
products industry (NAICS 325000), and the petroleum bulk stations and 
terminals industry (NAICS 424710). While we do not know the precise 
distribution of new and modified storage vessels across the affected 
sectors, we know that there are affected storage vessels in the sectors 
mentioned earlier in this preamble. These sectors contribute gross 
value added, ranging from $200 to $501 billion per sector, to the 
national economy. In comparison, the requirements in NSPS subpart Kc 
have estimated total costs of $21 million. The total cost is the total 
incurred collectively amongst numerous sectors, and each of the sectors 
examined has sales of at least $200 billion. Thus, the compliance costs 
of this action are insignificant relative to the scale for the sectors 
affected, and it is appropriate to evaluate the economic impacts by 
conducting a screening analysis comparing the costs to entity-level 
sales.
    Given the results of the analysis, these economic impacts are 
relatively low for affected industries and entities impacted by this 
final rule, and there will not be substantial impacts on the markets 
for affected products. The costs of the final rule are not expected to 
result in a significant market impact, regardless of whether they are 
passed on to the purchaser or absorbed by the firms. We also expect 
minimal impacts on employment.

D. What are the benefits?

    The final provisions in NSPS subpart Kc would reduce emissions of 
VOCs, some of which may also be HAPs. Because VOCs react in the 
atmosphere to produce ozone, these standards would help to reduce 
atmospheric ozone concentrations and reduce health effects associated 
with high levels of ozone. Furthermore, the final requirements to 
submit reports and test results electronically would improve 
monitoring, compliance, and implementation of the rule.

E. What analysis of environmental justice did we conduct?

    For purposes of analyzing regulatory impacts, under Executive Order 
12898, Federal Actions to Address Environmental Justice in Minority 
Populations and Low-Income Populations, the EPA relies upon its June 
2016 ``Technical Guidance for Assessing Environmental Justice in 
Regulatory Analysis,'' which provides recommendations that encourage 
analysts to conduct the highest quality analysis feasible, recognizing 
that data limitations, time, resource constraints, and analytical 
challenges will vary by media and circumstance. The Technical Guidance 
states that a regulatory action may involve potential EJ concerns if it 
could: (1) create new disproportionate impacts on communities with EJ 
concerns; (2) exacerbate existing disproportionate impacts on 
communities with EJ concerns; or (3) present opportunities to address 
existing disproportionate impacts on communities with EJ concerns 
through this action under development.
    The EPA's EJ technical guidance states that ``[t]he analysis of 
potential EJ concerns for regulatory actions should address three 
questions: (A) Are there potential EJ concerns associated with 
environmental stressors affected by the regulatory action for 
population groups of concern in the baseline? (B) Are there potential 
EJ concerns associated with environmental stressors affected by the 
regulatory action for population groups of concern for the regulatory 
option(s) under consideration? (C) For the regulatory option(s) under 
consideration, are potential EJ concerns created or mitigated compared 
to the baseline?'' \9\
---------------------------------------------------------------------------

    \9\ Technical Guidance for Assessing Environmental Justice in 
Regulatory Analysis, U.S. EPA, June 2016. Quote is from Section 3--
Key Analytic Considerations, page 11. https://www.epa.gov/environmentaljustice/technical-guidance-assessing-environmental-justice-regulatory-analysis.
---------------------------------------------------------------------------

    Because this action finalizes standards of performance for new, 
modified, and reconstructed sources that commence construction after 
October 4, 2023, the locations of the construction of new VOL storage 
vessels are not known. In addition, it is not known which of the 
existing facilities will be modified or reconstructed in the future. 
Therefore, we are unable to quantitatively estimate the potential 
environmental justice impact of NSPS subpart Kc. Over the next 5 years, 
the EPA estimates that 1,440 new tanks and 30 modified tanks would be 
subject to NSPS subpart Kc. We estimate that there are more than 10,000 
existing VOL storage vessels, but we do not have a list of specific 
storage vessels and their locations. Therefore, we cannot perform a 
proximity demographic analysis of populations near existing units as a 
proxy for units that may be modified or reconstructed and become 
subject to NSPS subpart Kc. Finally, because we based the analysis of 
the impacts and emission reductions on model plants, we cannot 
ascertain specifically how the potential benefits of this rule would be 
distributed across the population. Thus, we are limited in our ability 
to estimate the potential EJ impacts of this rule.
    The EPA expects that NSPS subpart Kc will ensure compliance via 
revised vapor pressure applicability thresholds, stricter seal 
requirements on IFR tanks, equivalent control requirements for EFRs, 
and strengthened closed vent system standards for vessels routed to a 
control device, fuel gas system, or process. This action finalizes 
standards of performance that apply at all times (including periods of 
SSM) and achieve an average 98 percent control efficiency. The rule 
will also increase data transparency through electronic reporting. 
Therefore, effects of emissions on populations in proximity to any 
future affected sources, including in communities potentially 
overburdened by pollution, which are often communities with EJ 
concerns, will be minimized due to the compliance with the standards of 
performance being finalized in this action.

VI. Statutory and Executive Order Reviews

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

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 14094: Modernizing Regulatory Review

    This action is not a significant regulatory action as defined in 
Executive Order 12866, as amended by Executive Order 14094, and was 
therefore not subject to a requirement for Executive Order 12866 
review.

B. Paperwork Reduction Act (PRA)

    The information collection activities in this rule have been 
submitted for approval to OMB under the PRA. The Information Collection 
Request (ICR) document that the EPA prepared has been assigned EPA ICR 
number 2791.01. You can find a copy of the ICR in the docket for this 
rule, and it is briefly summarized here. The information collection 
requirements are not enforceable until the Office of Management and 
Budget (OMB) approves them.
    The EPA is finalizing requirements for storage vessels, including 
periodic inspections based on the type of storage vessel. This 
information will be collected to assure compliance with NSPS subpart 
Kc.

[[Page 83316]]

    Respondents/affected entities: Owners or operators of VOL storage 
vessels.
    Respondent's obligation to respond: Mandatory (40 CFR part 60, 
subpart Kc).
    Estimated number of respondents: 588.
    Frequency of response: Initially and semiannually.
    Total estimated burden: 16,394 hours (per year). Burden is defined 
at 5 CFR 1320.3(b).
    Total estimated cost: $2,009,357 (per year), includes $528,240 in 
annualized capital and no operation or maintenance costs.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities contained in this final rule.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. The 
small entities subject to the requirements of this action are small 
businesses and small governmental jurisdictions that own or operate VOL 
storage vessels. The Agency has determined that small entities may 
experience an impact of likely below 1 percent relative to sales for 
any affected small entity, and an even larger margin before it would 
approach a 1 percent impact for a substantial number of small entities. 
Details of this analysis are presented in the memorandum Economic 
Impact Analysis for the New Source Performance Standards (NSPS) for the 
Volatile Organic Liquid Storage Vessels (Tanks) included in the docket.

D. Unfunded Mandates Reform Act (UMRA)

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

E. Executive Order 13132: Federalism

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

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

    This action does have Tribal implications as specified in Executive 
Order 13175. NSPS subpart Kb includes provisions for storage vessels 
that already have impacts on Tribal governments that have storage 
vessels with at least 20,000 gallons of capacity and that meet the 
vapor pressure thresholds for general rule applicability or control 
applicability. NSPS subpart Kc includes updates to the VOC standards 
and monitoring requirements for storage vessels that meet the revised 
vapor pressure thresholds for control. Additionally, basic requirements 
for determining a VOL's MTVP, recordkeeping, and good air pollution 
control practices are being finalized for all storage vessels greater 
than 20,000 gallons that only store VOLs with an MTVP greater than or 
equal to 0.25 psia. These changes will only impact storage vessels that 
are constructed, modified, or reconstructed after the proposal date.
    Consistent with the EPA Policy on Consultation and Coordination 
with Indian Tribes, the EPA offered government-to-government 
consultation with Tribes by sending a letter dated October 3, 2023, 
inviting all federally recognized Tribes to request a consultation. The 
EPA received one request for consultation. On November 8, 2023, the EPA 
met with the Tribe for the purposes of discussing NSPS subpart Kc and 
other issues but were unable to conduct consultation on this specific 
rulemaking.

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

    Executive Order 13045 directs Federal agencies to include an 
evaluation of the health and safety effects of the planned regulation 
on children in Federal health and safety standards and explain why the 
regulation is preferable to potentially effective and reasonably 
feasible alternatives. This action is not subject to Executive Order 
13045 because it is not economically significant as defined in 
Executive Order 12866 and because the EPA does not believe the 
environmental health or safety risks addressed by this action present a 
disproportionate risk to children. The final rule will reduce emissions 
of VOCs, some of which may also be HAPs. These standards will help to 
reduce atmospheric ozone concentrations and reduce health effects 
associated with high levels of ozone and are projected to improve 
overall health, including that of children.

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

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

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

    This action for NSPS subparts Kb and Kc involves technical 
standards. Therefore, the EPA conducted a search to identify 
potentially applicable voluntary consensus standards. However, the 
Agency identified no such standards. Searches were conducted for EPA 
Methods 1, 1A, 2, 2A, 2C, 2D, 3A, 3B, 3C, 4, 6, 10, 15, 16, 16A, 18, 
21, 22, and 25A of 40 CFR part 60, appendix A. The EPA has decided to 
use EPA Methods 21, 22, and 25A. Additional information for the 
voluntary consensus standard search and determinations can be found in 
the memorandum titled, Voluntary Consensus Standard Results for Review 
of Standards of Performance for Volatile Organic Liquid Storage Vessels 
(Including Petroleum Liquid Storage Vessels). All potential standards 
were reviewed to determine the practicality of the voluntary consensus 
standards for this rule. Although there were no applicable voluntary 
consensus standards identified, we are finalizing the proposal to amend 
40 CFR 60.17 to incorporate by reference two ASTM methods as discussed 
in section III.M. of the proposal preamble (88 FR 68550; October 4, 
2023). These include the following:
    <bullet> ASTM D6377-20, Standard Test Method for Determination of 
Vapor Pressure of Crude Oil: VPCRx (Expansion Method). The method is an 
automated device method for measuring vapor pressures for crude oils 
samples between 29 kPa and 180 kPa at 37.8 [deg]C. The method is 
suitable for testing with a 4:1 vapor-liquid ratio.
    <bullet> ASTM D6378-22, Standard Test Method for Determination of 
Vapor Pressure (VPX) of Petroleum Products, Hydrocarbons, and 
Hydrocarbon-Oxygenate Mixtures (Triple Expansion Method). The method is 
an automated device method for measuring vapor pressures between 7 kPa 
and 150 kPa at 37.8 [deg]C for tested samples with boiling points at 0 
[deg]C. The method is suitable for volatile organic liquids,

[[Page 83317]]

hydrocarbons and liquid petroleum products sampled at a 4:1 vapor-
liquid ratio.
    The ASTM standards are available from ASTM, International, 100 Barr 
Harbor Drive, Post Office Box C700, West Conshohocken, PA 19428-2959. 
See https://www.astm.org.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations and 
Executive Order 14096: Revitalizing Our Nation's Commitment to 
Environmental Justice for All

    The EPA believes that it is not practicable to assess whether the 
human health or environmental conditions that exist prior to this 
action result in disproportionate and adverse effects on communities 
with EJ concerns. Over the next 5 years, the EPA estimates that 1,440 
new tanks and 30 modified tanks will be subject to NSPS subpart Kc. 
However, the locations of any new VOL storage vessels that would be 
subject to NSPS subpart Kc are not known. Furthermore, there is 
insufficient data available regarding the locations of existing VOL 
storage vessels. The EPA estimates that there are more than 10,000 
existing storage vessels subject to NSPS subpart Kb, but we do not have 
a list of specific storage vessels and their locations. Therefore, we 
cannot perform a proximity demographic analysis of populations near 
existing storage vessels as a proxy for storage vessels that may be 
modified or reconstructed and become subject to NSPS subpart Kc. 
Finally, because we based the analysis of the impacts and emission 
reductions on model plants, we cannot ascertain specifically how the 
potential benefits of this rule would be distributed across the 
population. Thus, we are limited in our ability to estimate the 
potential EJ impacts of this rule.
    The information supporting this Executive Order review is contained 
in section V.E. of this document. All pertinent supporting documents 
such as the technical memorandum, Control Options for Storage Vessels 
(Docket ID No. EPA-HQ-OAR-2023-0358-0002), which discusses the costs 
and environmental impacts of the regulatory options considered, is in 
the docket.

K. Congressional Review Act (CRA)

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

List of Subjects in 40 CFR Part 60

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

Michael S. Regan,
Administrator.

    For the reasons set forth in the preamble, the Environmental 
Protection Agency is amending part 60 of title 40, chapter I, of the 
Code of Federal Regulations as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

0
1. The authority citation for part 60 continues to read as follows:

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

Subpart A--General Provisions

0
2. Amend Sec.  60.17 by:
0
a. Redesignating paragraphs (h)(198) through (233) as (h)(200) through 
(235); and
0
b. Adding paragraphs (h)(198) and (199).
    The additions read as follows:


Sec.  60.17  Incorporations by reference.

* * * * *
    (h) * * *
    (198) ASTM D6377-20, Standard Test Method for Determination of 
Vapor Pressure of Crude Oil: VPCR<INF>x</INF> (Expansion Method), 
(Approved June 1, 2020); IBR approved for Sec.  60.113c.
    (199) ASTM-D6378-22, Standard Test Method for Determination of 
Vapor Pressure (VPX) of Petroleum Products, Hydrocarbons, and 
Hydrocarbon-Oxygenate Mixtures (Triple Expansion Method), (Approved 
July 1, 2022); IBR approved for Sec.  60.113c.
* * * * *

Subpart Kb--Standards of Performance for Volatile Organic Liquid 
Storage Vessels (Including Petroleum Liquid Storage Vessels) for 
Which Construction, Reconstruction, or Modification Commenced After 
July 23, 1984, and On or Before October 4, 2023

0
3. Revise the heading of subpart Kb to read as set out above.

0
4. Amend Sec.  60.110b by revising paragraph (a) to read as follows:


Sec.  60.110b  Applicability and designation of affected facility.

    (a) Except as provided in paragraph (b) of this section, the 
affected facility to which this subpart applies is each storage vessel 
with a capacity greater than or equal to 75 cubic meters (m\3\) that is 
used to store volatile organic liquids (VOL) for which construction, 
reconstruction, or modification is commenced after July 23, 1984, and 
on or before October 4, 2023.
* * * * *

0
5. Amend Sec.  60.115b by:
0
a. Revising paragraphs (a), (b), and (d); and
0
b. Adding paragraphs (e), (f), and (g).
    The revisions and additions read as follows:


Sec.  60.115b  Reporting and recordkeeping requirements.

* * * * *
    (a) After installing control equipment in accordance with Sec.  
60.112b(a)(1) (fixed roof and internal floating roof), the owner or 
operator shall meet the following requirements.
    (1) Furnish the Administrator with a report that describes the 
control equipment and certifies that the control equipment meets the 
specifications of Sec.  60.112b(a)(1) and Sec.  60.113b(a)(1). Prior to 
October 15, 2024, this report shall be an attachment to the 
notification required by Sec.  60.7(a)(3). Beginning October 15, 2024, 
the owner or operator must submit all subsequent reports in PDF format 
following the procedures specified in paragraph (e) of this section.
    (2) Keep a record of each inspection performed as required by Sec.  
60.113b(a)(1), (a)(2), (a)(3), and (a)(4). Each record shall identify 
the storage vessel on which the inspection was performed and shall 
contain the date the vessel was inspected and the observed condition of 
each component of the control equipment (seals, internal floating roof, 
and fittings).
    (3) If any of the conditions described in Sec.  60.113b(a)(2) are 
detected during the annual visual inspection required by Sec.  
60.113b(a)(2), a report shall be furnished to the Administrator within 
30 days of the inspection. Each report shall identify the storage 
vessel, the nature of the defects, and the date the storage vessel was 
emptied or the nature of and date the repair was made. Beginning 
October 15, 2024, all subsequent reports must be submitted in PDF 
format following the procedures in paragraph (e) of this section.
    (4) After each inspection required by Sec.  60.113b(a)(3) that 
finds holes or tears in the seal or seal fabric, or defects in the 
internal floating roof, or other control equipment defects listed in 
Sec.  60.113b(a)(3)(ii), a report shall be furnished to the 
Administrator within 30 days of the inspection. The report shall 
identify the storage vessel and the

[[Page 83318]]

reason it did not meet the specifications of Sec.  60.112b(a)(1) or 
Sec.  60.113b(a)(3) and list each repair made. Beginning October 15, 
2024, all subsequent reports must be submitted in PDF format following 
the procedures in paragraph (e) of this section.
    (b) After installing control equipment in accordance with Sec.  
60.112b(a)(2) (external floating roof), the owner or operator shall 
meet the following requirements.
    (1) Furnish the Administrator with a report that describes the 
control equipment and certifies that the control equipment meets the 
specifications of Sec.  60.112b(a)(2) and Sec.  60.113b(b)(2), (b)(3), 
and (b)(4). Prior to October 15, 2024, this report shall be an 
attachment to the notification required by Sec.  60.7(a)(3). Beginning 
October 15, 2024, the owner or operator must submit all subsequent 
reports in PDF format following the procedures specified in paragraph 
(e) of this section.
    (2) Within 60 days of performing the seal gap measurements required 
by Sec.  60.113b(b)(1), furnish the Administrator with a report that 
contains the following information. Beginning October 15, 2024, all 
subsequent reports must be submitted in PDF format following the 
procedures in paragraph (e) of this section.
    (i) The date of measurement;
    (ii) The raw data obtained in the measurement; and
    (iii) The calculations described in Sec.  60.113b(b)(2) and (b)(3).
    (3) Keep a record of each gap measurement performed as required by 
Sec.  60.113b(b). Each record shall identify the storage vessel in 
which the measurement was performed and shall contain:
    (i) The date of measurement;
    (ii) The raw data obtained in the measurement; and
    (iii) The calculations described in Sec.  60.113b(b)(2) and (b)(3).
    (4) After each seal gap measurement that detects gaps exceeding the 
limitations specified by Sec.  60.113b(b)(4), submit a report to the 
Administrator within 30 days of the inspection. The report will 
identify the vessel and contain the information specified in paragraph 
(b)(2) of this section and the date the vessel was emptied or the 
repairs made and date of repair. Beginning October 15, 2024, all 
subsequent reports must be submitted in PDF format following the 
procedures in paragraph (e) of this section.
* * * * *
    (d) After installing a closed vent system and flare to comply with 
Sec.  60.112b, the owner or operator shall meet the following 
requirements.
    (1) A report containing the measurements required by Sec.  
60.18(f)(1) through (6) shall be furnished to the Administrator as 
required by Sec.  60.8 of the General Provisions. This report shall be 
submitted within 6 months of the initial start-up date. Beginning 
October 15, 2024, all subsequent reports must be submitted in PDF 
format following the procedures in paragraph (e) of this section.
    (2) Records shall be kept of all periods of operation during which 
the flare pilot flame is absent.
    (3) Semiannual reports of all periods recorded under Sec.  
60.115b(d)(2) in which the pilot flame was absent shall be furnished to 
the Administrator. Beginning October 15, 2024, all subsequent reports 
must be submitted in PDF format following the procedures specified in 
paragraph (e) of this section.
    (e) An owner or operator required to submit notifications or 
reports following the procedures specified in this paragraph (e) must 
submit notifications or reports to the EPA via the Compliance and 
Emissions Data Reporting Interface (CEDRI), which can be accessed 
through the EPA's Central Data Exchange (CDX) (https://cdx.epa.gov/). 
The EPA will make all the information submitted through CEDRI available 
to the public without further notice to the owner or operator. Do not 
use CEDRI to submit information the owner or operator claims as CBI. 
Although the EPA does not expect persons to assert a claim of CBI, if 
an owner or operator wishes to assert a CBI claim for some of the 
information in the report or notification, the owner or operator must 
submit a complete file in the format specified in this subpart, 
including information claimed to be CBI, to the EPA following the 
procedures in paragraphs (e)(1) and (2) of this section. Clearly mark 
the part or all of the information claimed to be CBI. Information not 
marked as CBI may be authorized for public release without prior 
notice. Information marked as CBI will not be disclosed except in 
accordance with procedures set forth in 40 CFR part 2. All CBI claims 
must be asserted at the time of submission. Anything submitted using 
CEDRI cannot later be claimed CBI. Furthermore, under CAA section 
114(c), emissions data is not entitled to confidential treatment, and 
the EPA is required to make emissions data available to the public. 
Thus, emissions data will not be protected as CBI and will be made 
publicly available. The owner or operator must submit the same file 
submitted to the CBI office with the CBI omitted to the EPA via the 
EPA's CDX as described earlier in this paragraph (e).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
<a href="/cdn-cgi/l/email-protection#80efe1f1f0f3e3e2e9c0e5f0e1aee7eff6"><span class="__cf_email__" data-cfemail="d3bcb2a2a3a0b0b1ba93b6a3b2fdb4bca5">[email protected]</span></a>, and as described above, should include clear CBI 
markings, and be flagged to the attention of the NSPS Kb Lead. Owners 
and operators who do not have their own file sharing service and who 
require assistance with submitting large electronic files that exceed 
the file size limit for email attachments should email <a href="/cdn-cgi/l/email-protection#9af5fbebeae9f9f8f3daffeafbb4fdf5ec"><span class="__cf_email__" data-cfemail="4c232d3d3c3f2f2e250c293c2d622b233a">[email protected]</span></a> 
to request a file transfer link.
    (2) If an owner or operator cannot transmit the file 
electronically, the owner or operator may send CBI information through 
the postal service to the following address: U.S. EPA, Attn: OAQPS 
Document Control Officer and NSPS Kb Lead, Mail Drop: C404-02, 109 T.W. 
Alexander, P.O. Box 12055, RTP, NC 27711. The mailed CBI material 
should be double wrapped and clearly marked. Any CBI markings should 
not show through the outer envelope.
    (f) Owners and operators required to electronically submit 
notifications or reports through CEDRI in the EPA's CDX may assert a 
claim of EPA system outage for failure to timely comply with the 
electronic submittal requirement. To assert a claim of EPA system 
outage, owners and operators must meet the requirements outlined in 
paragraphs (f)(1) through (7) of this section.
    (1) The owner or operator must have been or will be precluded from 
accessing CEDRI and submitting a required report within the time 
prescribed due to an outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning 5 business days prior to the date that the submission is due.
    (3) The outage may be planned or unplanned.
    (4) The owner or operator must submit notification to the 
Administrator in writing as soon as possible following the date the 
owner or operator first knew, or through due diligence should have 
known, that the event may cause or has caused a delay in reporting.
    (5) The owner or operator must provide to the Administrator a 
written description identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;

[[Page 83319]]

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

0
6. Amend Sec.  60.116b by revising paragraph (d) to read as follows:


Sec.  60.116b  Monitoring of operations.

* * * * *
    (d) Except as provided in paragraph (g) of this section, the owner 
or operator of each storage vessel either with a design capacity 
greater than or equal to 151 m\3\ storing a liquid with a maximum true 
vapor pressure that is normally less than 5.2 kPa or with a design 
capacity greater than or equal to 75 m\3\ but less than 151 m\3\ 
storing a liquid with a maximum true vapor pressure that is normally 
less than 27.6 kPa shall notify the Administrator within 30 days when 
the maximum true vapor pressure of the liquid exceeds the respective 
maximum true vapor pressure values for each volume range. Beginning 
October 15, 2024, all subsequent notifications must be submitted in PDF 
format following the procedures specified in Sec.  60.115b(e).
* * * * *

0
7. Amend Sec.  60.117b by revising paragraph (b) to read as follows:


Sec.  60.117b  Delegation of authority.

* * * * *
    (b) Authorities which will not be delegated to States: Sec. Sec.  
60.111b(f)(4), 60.114b, 60.116b(e)(3)(iii), 60.116b(e)(3)(iv), and 
60.116b(f)(2)(iii), and approval of an alternative to any electronic 
reporting to the EPA required by this subpart.

0
8. Add subpart Kc consisting of Sec. Sec.  60.110c through 60.117c to 
part 60 to read as follows:

Subpart Kc--Standards of Performance for Volatile Organic Liquid 
Storage Vessels (Including Petroleum Liquid Storage Vessels) for 
Which Construction, Reconstruction, or Modification Commenced After 
October 4, 2023

Sec.
60.110c Applicability and designation of affected facility.
60.111c Definitions.
60.112c Standard for volatile organic compounds (VOC).
60.113c Testing, monitoring, and inspection procedures.
60.114c Alternative means of emission limitation.
60.115c Recordkeeping requirements.
60.116c Reporting requirements.
60.117c Delegation of authority.


Sec.  60.110c  Applicability and designation of affected facility.

    (a) Except as provided in paragraph (b) of this section, the 
affected facility to which this subpart applies is each storage vessel 
with a capacity greater than or equal to 20,000 gallons (gal) (75.7 
cubic meters (m\3\)) that is used to store volatile organic liquids 
(VOL) for which construction, reconstruction, or modification is 
commenced after October 4, 2023.
    (b) This subpart does not apply to the following:
    (1) Vessels at coke oven by-product plants;
    (2) Pressure vessels designed to operate in excess of 29.7 pounds 
per square inch absolute (psia) (204.9 kilopascals (kPa) absolute) and 
without emissions to the atmosphere;
    (3) Vessels permanently attached to mobile vehicles such as trucks, 
railcars, barges, or ships;
    (4) Vessels with a design capacity less than or equal to 420,000 
gal (1,589.874 m\3\) used for petroleum or condensate stored, 
processed, or treated prior to custody transfer;
    (5) Vessels located at bulk gasoline plants as defined in 40 CFR 
63.11100;
    (6) Vessels located at gasoline service stations;
    (7) Vessels used to store beverage alcohol; or
    (8) Vessels that only store VOL with a maximum true vapor pressure 
less than 0.25 psia (1.7 kPa absolute).
    (c) Storage vessels that are affected facilities according to 
paragraph (a) of this section for which construction or reconstruction 
commenced after October 4, 2023 are subject to the standards in Sec.  
60.112c and the corresponding requirements in Sec. Sec.  60.113c 
through 60.116c as new sources any time they meet the specifications in 
either paragraph (c)(1) or (2) of this section, regardless of whether 
they initially contained VOL with a maximum true vapor pressure below 
the applicable threshold in paragraph (c)(1) or (2) of this section.
    (1) Storage vessels with a capacity greater than or equal to 40,000 
gal (151 m\3\) containing a VOL that, as stored, has a maximum true 
vapor pressure equal to or greater than 0.5 psia (3.4 kPa).
    (2) Storage vessels with a capacity greater than or equal to 20,000 
gal (75.7

[[Page 83320]]

m\3\) but less than 40,000 gal (151 m\3\) containing a VOL that, as 
stored, has a maximum true vapor pressure equal to or greater than 1.5 
psia (10.3 kPa).
    (d) Storage vessels that are affected facilities according to 
paragraph (a) of this section for which construction or reconstruction 
commenced on or before October 4, 2023, (``existing storage vessels'') 
and are modified after October 4, 2023, are subject to the standards in 
Sec.  60.112c and the corresponding requirements in Sec. Sec.  60.113c 
through 60.116c as modified sources any time they meet the 
specifications in either paragraph (d)(1) or (2) of this section.
    (1) For an existing storage vessel with a capacity greater than or 
equal to 40,000 gal (151 m\3\), containing a VOL that, as stored, has a 
maximum true vapor pressure equal to or greater than 0.5 psia (3.4 
kPa).
    (2) For an existing storage vessel with a capacity greater than or 
equal to 20,000 gal (75.7 m\3\) but less than 40,000 gal (151 m\3\), 
containing a VOL that, as stored, has a maximum true vapor pressure 
equal to or greater than 1.5 psia (10.3 kPa).
    (e) For the purposes of this subpart,
    (1) The phrase ``change in the method of operation of, an existing 
facility which increases the amount of any air pollutant'' in the 
definition of modification in Sec.  60.2 or ``operational change to an 
existing facility which results in an increase in the emission rate to 
the atmosphere of any pollutant to which a standard applies'' in Sec.  
60.14(a) means a change in operation occurs if the storage vessel is 
used to store a VOL that has a greater maximum true vapor pressure than 
all VOL historically stored or permitted; and
    (2) The exemption in Sec.  60.14(e)(4) regarding alternative fuel 
or raw material does not apply to storage vessels.
    (f) Storage vessels that are affected facilities according to 
paragraph (a) of this section and do not meet the criteria in either 
paragraph (c)(1), (c)(2), (d)(1), or (d)(2) of this section are subject 
to the requirements in Sec.  60.113c(d), if applicable, and Sec.  
60.115c(b).
    (g) All standards including emission limitations shall apply at all 
times, including periods of startup, shutdown and malfunction. As 
provided in Sec.  60.11(f), this paragraph (g) supersedes the 
exemptions for periods of startup, shutdown, and malfunction in subpart 
A of this part.
    (h) Owners or operators may choose to comply with the provisions of 
this subpart to demonstrate compliance with subparts K, Ka, and Kb of 
this part. Compliance with the provisions of this subpart, including 
all control requirements, recordkeeping, and reporting requirements, 
will constitute compliance with the applicable storage vessel 
provisions in subparts K, Ka, and Kb.
    (i) Owners or operators may choose to comply with this subpart to 
demonstrate compliance with 40 CFR part 63, subpart WW for storage 
vessels equipped with an internal or external floating roof that is 
subject to this subpart and 40 CFR part 63, subpart WW. Compliance with 
this subpart, including all floating roof requirements, recordkeeping, 
and reporting requirements, will constitute compliance with the 
applicable storage vessel provisions in 40 CFR part 63, subpart WW.


Sec.  60.111c  Definitions.

    Terms used in this subpart are defined in the Act, in subpart A of 
this part, or in this section as follows:
    Access hatch means an opening in the roof with a vertical well and 
a cover attached to it. Access hatch provides passage for workers and 
materials through the roof for construction or maintenance.
    Condensate means hydrocarbon liquid separated from natural gas that 
condenses due to changes in the temperature or pressure, or both, and 
remains liquid at standard conditions.
    Closed vent system means a system that is not open to the 
atmosphere and is composed of piping, ductwork, connections, and, if 
necessary, flow inducing devices that transport gas or vapor from an 
emission point to a control device. Closed vent system does not include 
the vapor collection system that is part of any tank truck or railcar.
    Custody transfer means the transfer of produced petroleum and/or 
condensate, after processing and/or treatment in the producing 
operations, from storage vessels or automatic transfer facilities to 
pipelines or any other forms of transportation.
    Degassing means the process of removing VOL vapors from a storage 
vessel during, or in preparation of, cleaning or when taking the 
storage vessel out of service for inspection, repair, or other reason.
    Enclosed combustion device means a thermal combustion device used 
to mix and ignite fuel, air pollutants, and air to provide a flame to 
heat and oxidize air pollutants and that emits the oxidized pollutants 
through a conveyance suitable to conduct a performance test. An 
enclosed combustion device may have recovery heat to preheat combustion 
air, but its primary purpose is for emission control and not to produce 
useful heat. Enclosed combustion devices include, but are not limited 
to, thermal oxidizers and incinerators. For the purpose of this 
subpart, process heaters and boilers are not enclosed combustion 
devices.
    External floating roof means a pontoon-type or double-deck type 
cover that rests on the liquid surface in a storage vessel without a 
fixed roof.
    Fill means the introduction of VOL into a storage vessel but not 
necessarily to complete capacity.
    Flare means a thermal combustion device using an open or shrouded 
flame (without full enclosure) such that the pollutants are not emitted 
through a conveyance suitable to conduct a performance test.
    Fuel gas system means the offsite and onsite piping and control 
system that gathers gaseous stream(s) generated by onsite operations, 
may blend them with other sources of gas, and transports the gaseous 
stream for use as fuel gas in combustion devices, or in- process 
combustion equipment such as furnaces and gas turbines, either singly 
or in combination.
    Gasoline service station means any site where gasoline is dispensed 
to motor vehicle fuel tanks from stationary storage vessels.
    Gauge float means a device that is used to indicate the level of 
liquid within the storage vessel. The float rests on the liquid surface 
and is housed inside a well that is closed by a removable cover.
    Gauge hatch/sample port/sample well means an opening in the roof 
that provides access for gauging or sampling. A gauge hatch is usually 
equipped with a closing cover or a funnel and slit-fabric seal to cover 
the opening.
    Internal floating roof means a floating roof located in a storage 
vessel with a fixed roof. For the purposes of this subpart, an external 
floating roof located in a storage vessel to which a fixed roof has 
been added is considered to be an internal floating roof.
    Liquid-mounted primary seal means a liquid or foam-filled seal 
mounted in continuous contact with the liquid between the wall of the 
storage vessel and the floating roof around the entire circumference of 
the storage vessel.
    Maximum true vapor pressure means the equilibrium partial pressure 
exerted by the volatile organic compounds (as defined in 40 CFR 51.100) 
in the stored VOL at the temperature equal to the highest calendar-
month average of the VOL storage temperature for VOLs stored above or 
below the ambient temperature or at the local maximum monthly average 
temperature as reported by the National Weather Service for VOLs stored 
at the ambient

[[Page 83321]]

temperature, as determined using the procedures specified in Sec.  
60.113c(d).
    Mechanical shoe primary seal means a metal sheet (the shoe) held 
vertically against the wall of the storage vessel by springs or 
weighted levels and is connected by braces to the floating roof. A 
flexible coated fabric (the envelope) spans the annular space between 
the metal sheet and the floating roof.
    Petroleum means the crude oil removed from the earth and the oils 
derived from tar sands, shale, and coal.
    Petroleum liquids means petroleum, condensate, and any finished or 
intermediate products manufactured in a petroleum refinery.
    Pressure release means the emission of materials resulting from the 
system pressure being greater than the set pressure of the pressure 
relief device or resulting from vacuum breaking device failing to close 
prior to the system reaching atmospheric pressure. This release can be 
one release or a series of releases over a short time period.
    Pressure relief device means a valve, rupture disk, or similar 
device used only to release an unplanned, nonroutine discharge of gas 
from process equipment in order to avoid safety hazards or equipment 
damage. Devices with low opening pressures must be monitored as bypass 
lines. A pressure relief device discharge can result from an operator 
error, a malfunction such as a power failure or equipment failure, or 
other unexpected cause. Such devices include conventional, spring-
actuated relief valves, balanced bellows relief valves, pilot-operated 
relief valves, rupture disks, and breaking, buckling, or shearing pin 
devices. Devices that are actuated only by a vacuum are not pressure 
relief devices. If a device has both a pressure relief function and a 
vacuum breaking function, such as a conservation vent, the portion of 
the conservation vent that acts to relieve pressure is considered a 
pressure relief device and the portion of the conservation vent that 
acts to relieve vacuum is a vacuum breaking device and not a pressure 
relief device.
    Process tank means a tank that is used within a process (including 
a solvent or raw material recovery process) to collect material 
discharged from a feedstock storage vessel or equipment within the 
process before the material is transferred to other equipment within 
the process, to a product or by-product storage vessel, or to a vessel 
used to store recovered solvent or raw material. In many process tanks, 
unit operations such as reactions and blending are conducted. Other 
process tanks, such as surge control vessels and bottoms receivers, 
however, may not involve unit operations.
    Reid vapor pressure means the absolute vapor pressure of volatile 
crude oil and volatile nonviscous petroleum liquids except liquified 
petroleum gases.
    Rim-mounted secondary seal means a secondary seal mounted on the 
rim of the floating roof of a storage vessel and forms continuous seal 
from the rim of the floating roof to the wall of the storage vessel.
    Rim seal system means a primary seal or a primary and secondary 
seal, which is mounted above the primary seal, and is attached to the 
deck perimeter and contacts the storage vessel wall.
    Rim vent means a device consisting of a weighted pallet that rests 
on a valve seat. Rim vents are used to release any excess pressure or 
vacuum present in the vapor pocket between the seal and the rim area of 
a floating roof storage vessel.
    Routed to a process or route to a process means the emissions are 
conveyed by hardpiping or a closed vent system to any enclosed portion 
of a process unit where the emissions are predominately recycled and/or 
consumed in the same manner as a material that fulfills the same 
function in the process; and/or transformed by chemical reaction into 
materials that are not volatile organic liquids; and/or incorporated 
into a product; and/or recovered.
    Storage vessel means each tank, reservoir, or container used for 
the storage of volatile organic liquids but does not include:
    (1) Frames, housing, auxiliary supports, or other components that 
are not directly involved in the containment of liquids or vapors;
    (2) Subsurface caverns or porous rock reservoirs; or
    (3) Process tanks.
    Vacuum breaker/automatic bleeder vent means a device used to 
equalize the pressure of the vapor space across the deck of a floating 
roof as the floating roof is either being landed on or floated off its 
roof supports. A vacuum breaker/automatic bleeder vent consists of a 
well with a cover. The cover is designed to open as the floating roof 
is landed. Opening of the cover may be accomplished by mechanisms such 
as leg actuation or pressure actuation.
    Vacuum breaking device means a device on a fixed roof of a storage 
vessel used to prevent mechanical failure of the storage vessel due to 
vacuum created as liquids are withdrawn from the storage vessel. If a 
device has both a pressure relief function and a vacuum breaking 
function, such as a conservation vent, the portion of the conservation 
vent that acts to relieve vacuum is considered a vacuum breaking device 
and the portion of the conservation vent that acts to relieve excess 
pressure is a pressure relief device and not a vacuum breaking device.
    Volatile organic liquid (VOL) means any organic liquid which can 
emit volatile organic compounds (as defined in 40 CFR 51.100) into the 
atmosphere.
    Waste means any liquid resulting from industrial, commercial, 
mining, or agricultural operations, or from community activities that 
is discarded or is being accumulated, stored, or physically, 
chemically, or biologically treated prior to being discarded or 
recycled.


Sec.  60.112c  Standard for volatile organic compounds (VOC).

    (a) General storage vessel control requirements. You must equip and 
operate each storage vessel affected facility meeting the thresholds in 
Sec.  60.110c(c)(1), (c)(2), (d)(1), or (d)(2) as specified in 
paragraphs (a)(1) through (4) of this section, as applicable.
    (1) For each storage vessel affected facility containing a VOL 
that, as stored, has a maximum true vapor pressure less than 11.1 psia 
(76.6 kPa), you may elect to install and operate either an internal 
floating roof meeting the requirements in paragraph (b) of this 
section, an external floating roof meeting the requirements in 
paragraph (c) of this section, or a closed vent system routed to a 
control device, fuel gas system, or process as specified in paragraph 
(d) of this section.
    (2) For each storage vessel affected facility containing a VOL 
that, as stored, has a maximum true vapor pressure of 11.1 psia (76.6 
kPa) or more, you must install and operate a closed vent system routed 
to a control device, fuel gas system, or process as specified in 
paragraph (d) of this section.
    (3) For each storage vessel affected facility complying with the 
closed vent system routed to a control device, fuel gas system, or 
process provisions specified in paragraph (d) of this section 
regardless of size and for each storage vessel with a design capacity 
greater than or equal to 1,000,000 gal (3,790 m\3\) containing a VOL 
that, as stored, has a maximum true vapor pressure equal to or greater 
than 1.5 psia (10.3 kPa), you must also comply with the requirements in 
paragraph (e) of this section.
    (4) You must meet the applicable testing, monitoring, and 
inspection requirements specified in Sec.  60.113c, recordkeeping 
requirements specified in Sec.  60.115c, and reporting requirements 
specified in Sec.  60.116c.

[[Page 83322]]

    (b) Requirements for an internal floating roof. You must equip and 
operate each internal floating roof as specified in paragraphs (b)(1) 
through (16) of this section, as applicable.
    (1) The internal floating roof must rest or float on the liquid 
surface (but not necessarily in complete contact with it) inside a 
storage vessel that has a fixed roof. The internal floating roof must 
be floating on the liquid surface at all times, except during initial 
fill and during those intervals when the storage vessel is completely 
emptied or subsequently emptied and refilled. When the roof is resting 
on the roof supports, the process of filling, emptying, or refilling 
must be continuous and must be accomplished as rapidly as possible.
    (2) Except as provided in paragraph (b)(14) of this section, each 
internal floating roof must be equipped with the following closure 
devices between the wall of the storage vessel and the edge of the 
internal floating roof:
    (i) Two seals mounted one above the other so that each forms a 
continuous closure that completely covers the space between the wall of 
the storage vessel and the edge of the internal floating roof. The 
lower seal is referred to as the primary seal, and the upper seal is 
referred to as the secondary seal.
    (ii) The primary seal must be either a mechanical shoe seal or a 
liquid-mounted seal. If a mechanical shoe seal is used, it must be 
installed so that one end of the shoe extends into the stored VOL and 
the other end extends a minimum vertical distance of 6 inches (15 
centimeters) above the stored organic liquid surface.
    (iii) The secondary seal must be rim-mounted.
    (3) Each opening in a noncontact internal floating roof except for 
vacuum breaker/automatic bleeder vents and the rim vents is to provide 
a projection below the liquid surface.
    (4) Vacuum breaker/automatic bleeder vents must be equipped with a 
gasket and are to be closed at all times, with no visible gaps, when 
the roof is floating. Vacuum breaker/automatic bleeder vents must be 
set to open only when the roof is being floated off or is being landed 
on the roof supports.
    (5) Rim vents must be equipped with a gasket and must be closed at 
all times with no visible gaps when the roof is floating. Rim vents 
must be set to open only when the internal floating roof is not 
floating or when the pressure beneath the rim seal system exceeds the 
manufacturer's recommended setting.
    (6) Each penetration of the internal floating roof for the purpose 
of sampling must be a gauge hatch/sample well. Except as specified in 
paragraph (b)(14) of this section, the gauge hatch/sample well must 
have a gasketed cover, which must be closed at all times, with no 
visible gaps, except when the hatch or well must be opened for access.
    (7) Each access hatch and gauge float well must be equipped with a 
cover that is gasketed and that is bolted or otherwise mechanically 
secured. The cover must be closed and must be bolted or otherwise 
mechanically secured at all times, with no visible gaps, except when 
the hatch or well must be opened for access.
    (8) Each penetration of the internal floating roof that allows for 
passage of a column supporting the fixed roof must have a flexible 
fabric sleeve seal or a gasketed sliding cover.
    (9) Each penetration of the internal floating roof that allows for 
passage of an unslotted leg ladder or unslotted ladder/guidepole 
combination must have a gasketed sliding cover. The cover must be 
closed at all times, with no visible gaps, except when the well must be 
opened for access.
    (10) Each slotted guidepole must be equipped with one of the 
controls specified in paragraphs (b)(10)(i) through (v) of this 
section. The covers must be designed to be closed at all times, with no 
visible gaps, except when the cover must be opened for access.
    (i) Gasketed sliding well cover, with pole sleeve. The sleeve must 
extend into the stored liquid.
    (ii) Gasketed sliding well cover, with pole sleeve and pole wiper. 
The sleeve must extend into the stored liquid.
    (iii) Gasketed sliding well cover, with pole float and pole wiper. 
The wiper or seal of the pole float must be at or above the height of 
the pole wiper.
    (iv) Gasketed sliding well cover, with pole float, pole sleeve, and 
pole wiper. The sleeve must extend into the stored liquid. The wiper or 
seal of the pole float must be at or above the height of the pole 
wiper.
    (v) A flexible device that completely encloses the slotted 
guidepole and eliminates the hydrocarbon vapor emissions pathway from 
inside the storage vessel through the guidepole slots to the outside 
air; a gasketed guidepole cover at the top of the guidepole; and a 
gasketed sliding well cover positioned at the top of the guidepole well 
that seals any openings between the well cover and the guidepole (e.g., 
pole wiper), any openings between the well cover and any other objects 
that pass through the well cover, and any other openings in the top of 
the guidepole well.
    (11) Ladder-slotted guidepole combination wells must be equipped 
with a gasketed sliding well cover and a ladder sleeve. The sliding 
well cover must be designed to be closed at all times with no visible 
gaps, except when gauging or sampling.
    (12) Unslotted guidepoles must be equipped with one of the controls 
specified in paragraph (b)(12)(i) or (ii) of this section. The controls 
must be designed to be closed at all times with no visible gaps.
    (i) A gasketed guidepole cover at the top of the guidepole; a 
gasketed sliding well cover; and a pole sleeve. The guidepole cover 
must be closed at all times, except when required to be opened for 
access. The gasketed sliding well cover must seal any openings between 
the well cover and the guidepole, any openings between the well cover 
and any other objects that pass through the well cover, and any other 
openings in the top of the guidepole well.
    (ii) A gasketed guidepole cover at the top of the guidepole; a 
gasketed sliding well cover; and a pole wiper. The guidepole cover must 
be closed at all times, except when required to be opened for access. 
The gasketed sliding well cover must seal any openings between the well 
cover and the guidepole (e.g., pole wiper), any openings between the 
well cover and any other objects that pass through the well cover, and 
any other openings in the top of the guidepole well.
    (13) Except for leg sleeves and stub drains, each opening in the 
internal floating roof not specified in paragraphs (b)(4) through (12) 
of this section, must be equipped with a cover or lid which is to be 
maintained in a closed position at all times (i.e., no visible gap) 
except when the device must be opened for access. The cover or lid must 
be equipped with a gasket.
    (14) For each modified storage vessel as specified in Sec.  
60.110c(d) with an existing internal floating roof, you may elect to 
comply with the rim seal system requirements in Sec.  60.112b(a)(1)(ii) 
or Sec.  60.110b(e) instead of the requirements in paragraph (b)(2) of 
this section, and you may elect to comply with the gauge hatch/sample 
well requirements in Sec.  60.112b(a)(1)(vii) or Sec.  60.110b(e) 
instead of the requirements in paragraph (b)(6) of this section.
    (15) A system equivalent to those described in paragraphs (b)(1) 
though (14) of this section, as applicable, as provided in Sec.  
60.114c.
    (16) Equip, maintain, and operate each internal floating roof 
control system to maintain the vapor concentration above the floating 
roof at or below 25 percent of the lower explosive limit (LEL) on a 5-
minute

[[Page 83323]]

rolling average basis without the use of purge gas. This standard may 
require additional controls, such as improved seam seals, beyond those 
specified in paragraphs (b)(1) through (15) of this section. Compliance 
with this paragraph (b)(16) must be determined using the methods in 
Sec.  60.113c(a)(3). Exceeding the LEL is considered an inspection 
failure under Sec.  60.113c(a)(2)(i) and must be remedied as such. Any 
repairs made must be confirmed effective through re-monitoring of the 
LEL and meeting the limits in this paragraph (b)(16) within the 
timeframes specified in Sec.  60.113c(a)(2)(i).
    (c) Requirements for an external floating roof. You must equip and 
operate each external floating roof as specified in paragraphs (c)(1) 
through (4) of this section.
    (1) The roof must be floating on the liquid at all times (i.e., off 
the roof supports) except during initial fill until the roof is lifted 
off roof supports and when the storage vessel is completely emptied or 
subsequently emptied and refilled. The process of filling, emptying, or 
refilling when the roof is resting on the roof supports must be 
continuous and must be accomplished as rapidly as possible.
    (2) Each external floating roof must be equipped with a primary and 
secondary rim seal system as specified in paragraph (b)(2) of this 
section, except that if a mechanical shoe primary seal is used, it must 
be installed so that one end of the shoe extends into the stored VOL 
and the other end extends a minimum vertical distance of 24 inches (61 
centimeters) above the stored organic liquid surface. The external 
floating roof also must have welded deck seams, and it must have deck 
fitting controls as specified in paragraphs (c)(2)(i) through (ix) of 
this section, as applicable. References to an internal floating roof in 
paragraph (b)(2) of this section means an external floating roof for 
the purposes of this paragraph (c)(2).
    (i) Each opening in an external floating roof except for vacuum 
breaker/automatic bleeder vents and the rim vents is to provide a 
projection below the liquid surface.
    (ii) Vacuum breaker/automatic bleeder vents must be equipped with a 
gasket and are to be closed at all times, with no visible gaps, when 
the roof is floating. Vacuum breaker/automatic bleeder vents must be 
set to open only when the roof is being floated off or is being landed 
on the roof supports.
    (iii) Rim vents must be equipped with a gasket and must be closed 
at all times with no visible gaps when the roof is floating. Rim vents 
must be set to open only when the external floating roof is not 
floating or when the pressure beneath the rim seal system exceeds the 
manufacturer's recommended setting.
    (iv) Each penetration of the external floating roof for the purpose 
of sampling must be a gauge hatch/sample well. The gauge hatch/sample 
well must have a gasketed cover, which must be closed at all times, 
with no visible gaps, except when the hatch or well must be opened for 
access.
    (v) Each access hatch and gauge float well must be equipped with a 
cover that is gasketed and that is bolted or otherwise mechanically 
secured. The cover must be closed and must be bolted or otherwise 
mechanically secured at all times, with no visible gaps, except when 
the hatch or well must be opened for access.
    (vi) Except as specified in paragraph (c)(3) of this section, if 
the external floating roof does not have a liquid-mounted primary seal, 
all guidepoles must be unslotted and must be equipped as specified in 
paragraph (b)(12) of this section.
    (vii) Except as specified in paragraph (c)(3) of this section, if 
the external floating roof has a liquid-mounted primary seal, equip 
each guidepole as specified in paragraphs (c)(2)(vii)(A) and (B) of 
this section.
    (A) Each slotted guidepole must be equipped as specified in 
paragraphs (b)(10)(ii) or (iv) of this section.
    (B) Each unslotted guidepole must be equipped as specified in 
paragraph (b)(12) of this section.
    (viii) Each emergency roof drain is to be provided with a slotted 
membrane fabric cover that covers at least 90 percent of the area of 
the opening.
    (ix) Except for leg sleeves, each opening in the external floating 
roof not subject to controls specified in paragraphs (c)(2)(i) through 
(viii) of this section must be equipped with a cover or lid which is to 
be maintained in a closed position at all times (i.e., no visible gap), 
except when the device must be opened for access. The cover or lid must 
be equipped with a gasket.
    (3) For each modified storage vessel as specified in Sec.  
60.110c(d) with an existing external floating roof, you may elect to 
comply with any of the guidepole controls specified in paragraphs 
(b)(10) and (12) of this section regardless of the type of primary seal 
used.
    (4) A system equivalent to those described in paragraphs (c)(1) 
through (3) of this section as provided in Sec.  60.114c.
    (d) Requirements for closed vent system routed to a control device, 
fuel gas system, or process. You must design, install, and operate each 
affected storage vessel with a closed vent system that routes to a 
control device, fuel gas system, or process as specified in paragraphs 
(d)(1) through (7) of this section.
    (1) The storage vessel must be designed and operated to be routed 
through a closed vent system to a control device, fuel gas system, or 
process at all times the storage vessel contains VOL without venting to 
the atmosphere through either meeting the storage vessel design 
requirements specified in paragraph (d)(1)(i) of this section or the 
vapor recovery system design requirements specified in paragraph 
(d)(1)(ii) of this section. Compliance with this requirement must be 
demonstrated according to paragraph (d)(1)(iii) of this section. Any 
vacuum breaking device on the storage vessel must close while the 
storage vessel is still under vacuum of at least -0.1 inches of water 
(-0.0036 psig or -0.025 kPa gauge).
    (i) The storage vessel must be designed to operate at a gauge 
pressure of no less than 1 psi greater than the maximum true vapor 
pressure of the stored liquid and any back pressure anticipated when 
the storage vessel is filled at its maximum rate without venting to the 
atmosphere.
    (ii) The vapor recovery system must be designed and operated to 
maintain the pressure in each storage vessel routed to a control device 
below the venting pressure of that storage vessel.
    (iii) You must equip each pressure relief device and vacuum 
breaking device on a storage vessel with a device(s) or use a 
monitoring system that is capable of meeting the requirements in 
paragraphs (d)(1)(iii)(A) through (C) of this section. If all emissions 
from a pressure relief device are routed through a closed vent system 
to a control device, process, or fuel gas system, then you are not 
required to comply with the requirements of this paragraph (d)(1)(iii).
    (A) Identifying the pressure release.
    (B) Recording the time and duration of each pressure release.
    (C) Notifying operators immediately that a pressure release is 
occurring. The device or monitoring system must be either specific to 
the pressure relief device or vacuum breaking device itself or must be 
associated with each storage vessel to indicate a pressure release to 
the atmosphere. Examples of these types of devices and systems include, 
but are not limited to, a rupture disk indicator, magnetic sensor, 
motion detector on the pressure relief valve stem, flow monitor, or 
pressure monitor.

[[Page 83324]]

    (2) Except for closed vent systems operated and maintained under 
negative pressure, each closed vent system must meet the requirements 
specified in paragraphs (d)(2)(i) through (iii) of this section.
    (i) The closed vent system must be designed to collect all VOC 
vapors and gases discharged from the storage vessel and operated with 
no detectable emissions as indicated by an instrument reading of less 
than 500 parts per million by volume (ppmv) above background, as 
determined using Method 21 of appendix A-7 to this part as specified in 
Sec.  60.113c(c)(2) and (3), and as determined by observations for 
visible, audible, and olfactory indications of leaks. Visible, audible, 
and olfactory inspections must be performed quarterly and Method 21 of 
appendix A-7 instrument monitoring must be conducted at least annually.
    (ii) Except for pressure relief devices and except for open-ended 
valves or lines that use a cap, blind flange, plug, or second valve and 
follow the requirements specified in Sec.  60.482-6(a)(2), (b), and (c) 
or follow requirements codified in another regulation that are the same 
as Sec.  60.482-6(a)(2), (b), and (c), you must comply with the 
provisions of either paragraph (d)(2)(ii)(A) or (B) of this section for 
each closed vent system that contains bypass lines that could divert a 
vent stream to the atmosphere.
    (A) Properly install, maintain, and operate a flow indicator that 
is capable of taking readings every 15 minutes. Install the flow 
indicator at the entrance to any bypass line.
    (B) Secure the bypass line valve in the non-diverting position with 
a car-seal or a lock-and-key type configuration.
    (iii) You must equip each pressure relief device on a closed vent 
system with a device(s) or use a monitoring system that is capable of 
meeting the requirements in paragraphs (d)(2)(iii)(A) through (C) of 
this section. If all releases and potential leaks from a pressure 
relief device are routed through a closed vent system to a control 
device, process, or fuel gas system, then you are not required to 
comply with the requirements of this paragraph (d)(2)(iii).
    (A) Identifying the pressure release.
    (B) Recording the time and duration of each pressure release.
    (C) Notifying operators immediately that a pressure release is 
occurring. The device or monitoring system must be either specific to 
the pressure relief device itself or must be associated with the 
process system or piping, sufficient to indicate a pressure release to 
the atmosphere. Examples of these types of devices and systems include, 
but are not limited to, a rupture disk indicator, magnetic sensor, 
motion detector on the pressure relief valve stem, flow monitor, or 
pressure monitor.
    (3) If you route emissions from a storage vessel to a control 
device, the control device must be designed and operated to reduce 
inlet VOC emissions by 98 percent or greater. If a flare is used as the 
control device or if an enclosed combustion device is used for which 
you elect to comply with the flare operating limits, you must meet the 
specifications described in paragraph (d)(5) of this section. The 
control device must be operated at all times when emissions from an 
affected storage vessel are routed to it except as provided in 
paragraph (d)(7) of this section.
    (4) A system equivalent to those described in paragraphs (d)(1) 
through (3) of this section as provided in Sec.  60.114c.
    (5) If you route from a storage vessel to a flare or enclosed 
combustion device for with you elect to comply with these flare 
operating limits, you must meet all applicable requirements specified 
in 40 CFR 63.670(b) through (g) and (i) through (n) except as provided 
in paragraphs (d)(5)(i) through (v) of this section.
    (i) For the purpose of this subpart,
    (A) The term ``regulated materials'' refers to ``vapors from a 
storage vessel affected facility'';
    (B) The term ``pilot flame'' means ``pilot flame or flare flame'';
    (C) The terms ``petroleum refinery'' and ``refinery'' mean 
``storage vessel affected facility''.
    (ii) For visible emissions, use the following text instead of 40 
CFR 63.670(c): The owner or operator shall operate with no visible 
emissions, except for periods not to exceed a total of five (5) minutes 
during any two (2) consecutive hours, when regulated material is routed 
to the flare. You must monitor for visible emissions from the flare as 
specified in Sec.  60.113c(c)(1)(iv)(A).
    (iii) The phrase ``and the flare vent gas flow rate is less than 
the smokeless design capacity of the flare'' in 40 CFR 63.670(d) for 
flare tip velocity requirements does not apply.
    (6) If you route emissions from a storage vessel to a fuel gas 
system or process, you must meet the requirements in paragraphs 
(d)(6)(i) through (iv) of this section, as applicable.
    (i) The fuel gas system or process must be operating at all times 
when emissions from an affected storage vessel are routed to it.
    (ii) If all emissions are routed to a process, the VOL in the 
emissions must meet one or more of the conditions specified in 
paragraphs (d)(6)(ii)(A) through (D) of this section and you must 
comply with the compliance demonstration requirements in paragraph 
(d)(6)(iii) of this section.
    (A) Recycled and/or consumed in the same manner as a material that 
fulfills the same function in that process.
    (B) Transformed by chemical reaction into materials that are not 
regulated materials.
    (C) Incorporated into a product.
    (D) Recovered.
    (iii) To demonstrate compliance with paragraph (d)(6)(ii) of this 
section for an affected storage vessel, you must prepare a design 
evaluation (or engineering assessment) that demonstrates the extent to 
which one or more of the conditions specified in paragraphs 
(d)(6)(ii)(A) through (D) of this section are being met.
    (iv) If emissions from an affected storage vessel are routed to a 
fuel gas system, you must submit the statement of connection for fuel 
gas systems specified in Sec.  60.116c(a)(7).
    (7) To the extent practical, routine maintenance on the control 
device should be conducted when the storage vessel(s) is(are) out of 
VOL service. If you comply with all the provisions in paragraphs 
(d)(7)(i) through (iv) of this section, you may conduct routine 
maintenance on a control device while one or more storage vessels 
vented to the control device are storing a VOL.
    (i) The storage vessel(s) storing VOL must be designed to operate 
above the maximum true vapor pressure of the stored VOL according to 
paragraph (d)(1)(i) of this section.
    (ii) The control device must be isolated from the storage vessel(s) 
using valves(s), blind flange(s), or similar device(s) at the control 
device or in the closed vent system as near as practical to the control 
device. You may purge the control device and downstream portion of the 
closed vent system to remove potentially explosive vapors and create a 
safe work environment only after the control device is isolated from 
the storage vessel(s).
    (iii) You must continue to comply with the bypass and pressure 
relief device monitoring requirements in paragraphs (d)(1)(iii), 
(d)(2)(ii), and (d)(2)(iii) of this section and their associated 
recordkeeping and reporting requirements. If there are multiple storage 
vessels connected to the closed vent system with significantly 
different pressure design limits, you must isolate individual storage 
vessels to prevent venting during planned maintenance.

[[Page 83325]]

Compliance with this paragraph (d)(7)(iii) may limit VOL addition to 
the storage vessel. If VOL is added to the storage vessel, there must 
be an approximately equivalent withdrawal of VOL such that the liquid 
level does not rise sufficiently to increase the pressure in the 
storage vessel to cause a pressure release from the storage vessel or 
the closed vent system.
    (iv) During this routine maintenance period the affected storage 
vessels cannot be actively degassed. If the storage vessel is to be 
emptied and actively degassed, the planned maintenance activity must be 
conducted when the storage vessel is out of VOL service.
    (e) Requirements for storage vessel degassing. For each storage 
vessel meeting the specifications in paragraph (a)(3) of this section, 
you must meet the requirements in paragraphs (e)(1) through (3) of this 
section during emptying and degassing of a storage vessel until the 
vapor space concentration in the storage vessel is less than 10 percent 
of the LEL or, for nonflammable liquids, 5,000 ppmv as methane. You 
must determine the LEL or methane concentration using process 
instrumentation or a portable measurement device and follow procedures 
for calibration and maintenance according to manufacturer's 
specifications. You must check instrument calibration and check the 
instrumental offset response each day the instrument is used and prior 
to discontinuing controlled degassing to confirm the accuracy of the 
instrument's readings.
    (1) Remove liquids from the storage vessel as much as practicable. 
Chemicals or a diluent such as a distillate fuel may be introduced into 
the storage vessel for the purpose of reducing vapor concentration 
before or during active degassing.
    (2) Comply with one of the following:
    (i) Reduce total VOC emissions by venting emissions through a 
closed vent system to a flare or enclosed combustion device for which 
you elect to comply with the flare provisions and meet the requirements 
specified in paragraph (d)(5) of this section.
    (ii) Reduce total VOC emissions by 98 weight percent by venting 
emissions through a closed vent system to any combination of non-flare 
control devices.
    (iii) Reduce total VOC emissions by routing emissions to a fuel gas 
system or process and meet the requirements specified in paragraph 
(d)(6) of this section.
    (3) For floating roof storage vessels, the storage vessel may be 
opened to set up equipment (e.g., making connections to a temporary 
control device) for the shutdown operations but must not be actively 
degassed during this time period.


Sec.  60.113c  Testing, monitoring, and inspection procedures.

    For each storage vessel subject to the provision in Sec.  
60.112c(a), you must meet the requirements of paragraph (a) of this 
section if you installed an internal floating roof, paragraph (b) of 
this section if you installed an external floating roof, or paragraph 
(c) of this section if you route emissions through a closed vent system 
to a control device, fuel gas system, or process. You must also meet 
the applicable requirements of paragraph (d) of this section.
    (a) Requirements for an internal floating roof. After installing 
the control equipment for an internal floating roof to meet the 
provisions in Sec.  60.112c(b), you must meet the requirements 
specified in paragraphs (a)(1) through (5) of this section.
    (1) Visually inspect the internal floating roof, the primary seal, 
the secondary seal (if one is in service), and deck fittings prior to 
filling the storage vessel with VOL. Any of the conditions described in 
paragraphs (a)(1)(i) through (iii) of this section constitutes 
inspection failure. You must repair the items before filling the 
storage vessel.
    (i) Holes, tears, or other openings in the primary seal, the 
secondary seal, or the seal fabric;
    (ii) Defects in the internal floating roof; or
    (iii) A rim seal or deck fitting control not meeting the applicable 
requirements in Sec.  60.112c(b)(2) through (13).
    (2) Inspect the internal floating roof as specified in paragraph 
(a)(2)(i) of this section at least once every 12 calendar months after 
initial fill, and inspect the internal floating roof as specified in 
paragraph (a)(2)(ii) of this section each time the storage vessel is 
emptied and degassed, or at a frequency no greater than every 120 
calendar months, whichever occurs first.
    (i) Visually inspect the internal floating roof, the primary seal, 
the secondary seal (if one is service), and deck fittings, through 
openings in the fixed roof and conduct LEL monitoring. Any of the 
conditions described in paragraphs (a)(2)(i)(A) through (F) of this 
section constitutes inspection failure. Identification of holes or 
tears in the rim seal is required only for the seal that is visible 
from the top of the storage vessel. You must repair the items or empty 
and remove the storage vessel from service within 45 days. If a failure 
that is detected during inspections required in this paragraph 
(a)(2)(i) cannot be repaired within 45 days and if the storage vessel 
cannot be emptied within 45 days, you may request a 30-day extension 
from the Administrator. Such a request for an extension must document 
that alternate storage capacity is unavailable and specify a schedule 
of actions the company will take that will assure that the control 
equipment will be repaired or the storage vessel will be emptied as 
soon as possible.
    (A) Stored liquid on the floating roof;
    (B) The internal floating roof is not resting on the surface of the 
VOL inside the storage vessel;
    (C) Holes, tears, or other openings in the primary seal, the 
secondary seal, or the seal fabric;
    (D) Defects in the internal floating roof;
    (E) A rim seal or deck fitting control not meeting the applicable 
requirements in Sec.  60.112c(b)(2) through (13); or
    (F) The concentration measured according to paragraph (a)(3) of 
this section exceeds 25 percent of the LEL.
    (ii) Visually inspect the internal floating roof, the primary seal, 
the secondary seal (if one is in service), gaskets, slotted membranes, 
and sleeve seals (if any). Any of the conditions described in 
paragraphs (a)(2)(ii)(A) through (C) of this section constitutes an 
inspection failure. You must repair the items as necessary so that none 
of the conditions specified in this paragraph (a)(2)(ii) exist before 
refilling the storage vessel with VOL. The inspection may be performed 
entirely from the top side of the floating roof, as long as there is 
visual access to all deck fittings and rim seal system specified in 
Sec.  60.112c(b). You must repair the items or empty and remove the 
storage vessel from service within 45 days. If a failure that is 
detected during inspections required in this paragraph (a)(2)(ii) 
cannot be repaired within 45 days and if the storage vessel cannot be 
emptied within 45 days, you may request a 30-day extension from the 
Administrator. Such a request for an extension must document that 
alternate storage capacity is unavailable and specify a schedule of 
actions the company will take that will assure that the control 
equipment will be repaired or the storage vessel will be emptied as 
soon as possible.
    (A) Defects in the internal floating roof;
    (B) Holes, tears, or other openings in the primary seal, the 
secondary seal, or the seal fabric; or
    (C) A rim seal or deck fitting control not meeting the applicable 
requirements in Sec.  60.112c(b)(2) through (13).
    (3) Compliance with the LEL limit for internal floating roof 
storage vessels at

[[Page 83326]]

Sec.  60.112c(b)(16) must be determined based on the procedures 
specified in paragraphs (a)(3)(i) through (v) of this section. If 
tubing is necessary to obtain the measurements, the tubing must be non-
crimping and made of Teflon or other inert material.
    (i) You must conduct LEL monitoring as part of the annual 
inspection specified in paragraph (a)(2)(i) of this section and at 
other times upon request by the Administrator. If the measurement 
cannot be performed during the visual inspection due to wind speeds 
exceeding those specified in paragraph (a)(3)(iii)(C) of this section, 
the measurement must be performed within 30 days of the visual 
inspection. If there is an exceedance of the LEL limit, you must re-
monitor in accordance with Sec.  60.112c(b)(16) within 30 days after 
repair or placing the storage vessel back in service.
    (ii) The calibration of the LEL meter must be checked per 
manufacturer specifications immediately before and after the 
measurements as specified in paragraphs (a)(3)(ii)(A) and (B) of this 
section. If tubing will be used for the measurements, the tubing must 
be attached during calibration so that the calibration gas travels 
through the entire measurement system.
    (A) Conduct the span check using a calibration gas recommended by 
the LEL meter manufacturer. The calibration gas must contain a single 
hydrocarbon at a concentration of the vapor corresponding to 50 percent 
of the LEL (e.g., 2.50 percent by volume when using methane as the 
calibration gas). The vendor must provide a Certificate of Analysis for 
the gas, and the certified concentration must be within <plus-minus>2 
percent (e.g., 2.45 percent-2.55 percent by volume when using methane 
as the calibration gas). The LEL span response must be between 49 
percent and 51 percent. If the span check prior to the measurements 
does not meet this requirement, the LEL meter must be recalibrated or 
replaced. If the span check after the measurements does not meet this 
requirement, the LEL meter must be recalibrated or replaced, and the 
measurements must be repeated.
    (B) Check the instrumental offset response using a certified 
compressed gas cylinder of zero air or an ambient environment that is 
free of organic compounds. The pre-measurement instrumental offset 
response must be 0 percent LEL. If the LEL meter does not meet this 
requirement, the LEL meter must be recalibrated or replaced.
    (iii) Conduct the monitoring measurements as specified in 
paragraphs (a)(3)(iii)(A) through (D) of this section.
    (A) Measurements of the vapors within the internal floating roof 
storage vessel must be collected no more than 3 feet above the internal 
floating roof.
    (B) Measurements must be taken for a minimum of 20 minutes, logging 
the measurements at least once every 15 seconds, or until one 5-minute 
average as determined according to paragraph (a)(3)(v)(B) of this 
section exceeds the limit specified in Sec.  60.112c(b)(16).
    (C) Measurements shall be taken when the wind speed at the top of 
the storage vessel is 5 mph or less to the extent practicable, but in 
no case shall measurements be taken when the sustained wind speed at 
top of storage vessel is greater than the annual average wind speed at 
the site or 15 mph, whichever is less.
    (D) Measurements should be conducted when the internal floating 
roof is floating with limited product movement (limited filling or 
emptying of the storage vessel).
    (iv) To determine the actual concentration of the vapor within the 
storage vessel, the percent of the LEL ``as the calibration gas'' must 
be corrected according to one of the procedures in paragraph 
(a)(3)(iv)(A) or (B) of this section. Alternatively, if the LEL meter 
used has correction factors that can be selected from the meter's 
program, you may enable this feature to automatically apply one of the 
correction factors in paragraph (a)(3)(iv)(A) or (B) of this section.
    (A) Multiply the measurement by the published vapor correction 
factor for the specific LEL meter, stored VOL, and calibration gas 
used; or
    (B) If there is no published correction factor for the specific LEL 
meter used and the vapors of the stored VOL, multiply the measurement 
by the published correction factor for butane as a surrogate for 
determining the LEL of the vapors of the stored VOL. The correction 
factor must correspond to the calibration gas used.
    (v) Use the calculation procedures in paragraphs (a)(3)(v)(A) 
through (C) of this section to determine compliance with the LEL limit.
    (A) For each minute while measurements are being taken, determine 
the 1-minute average reading as the arithmetic average of the corrected 
individual measurements (taken at least once every 15 seconds) during 
the minute.
    (B) Starting with the end of the fifth minute of data, calculate a 
5-minute rolling average as the arithmetic average of the previous five 
1-minute readings determined under paragraph (a)(3)(v)(A) of this 
section. Determine a new 5-minute average reading for every subsequent 
1-minute reading.
    (C) Each 5-minute rolling average must meet the LEL limit specified 
in Sec.  60.112c(b)(16).
    (4) Notify the Administrator as specified in Sec.  60.116c(b) at 
least 30 days prior to the inspection of each storage vessel for which 
an inspection is required by paragraph (a)(1) or (a)(2)(ii) of this 
section to afford the Administrator the opportunity to have an observer 
present.
    (5) You must equip each affected storage vessel that has an 
internal floating roof with an alarm system that provides a visual or 
audible signal that alerts the operator when the internal floating roof 
is approaching the landed height and that provides a separate visual or 
audible signal to alert the operator when the roof has landed. The roof 
is considered landed when the floating roof first rests on supports or 
when the vacuum breaker/automatic bleeder vent begins to open, 
whichever is first (for example, when using a leg-actuated vent that 
triggers the vent prior to resting on the roof supports).
    (b) Requirements for an external floating roof. After installing 
the control equipment for an external floating roof to meet the 
provisions in Sec.  60.112c(c), you must inspect the external floating 
roof according to the specifications in paragraphs (b)(1) through (8) 
of this section.
    (1) Determine the gap areas and maximum gap widths, between the 
primary seal and the wall of the storage vessel and between the 
secondary seal and the wall of the storage vessel according to the 
frequency provided in paragraphs (b)(1)(i) and (ii) of this section. 
You must visually inspect all roof fittings to ensure that covers are 
closed and gasketed with no visible gaps and that there are no tears in 
sleeves, wipers, or similar controls used for a given fitting during 
each measurement of gaps as required under this paragraph (b)(1).
    (i) Measurements of gaps between the storage vessel wall and the 
primary seal (seal gaps) must be performed during the hydrostatic 
testing of the storage vessel or within 60 days of the initial fill 
with VOL and at least once every 60 calendar months thereafter.
    (ii) Measurements of gaps between the storage vessel wall and the 
secondary seal must be performed within 60 days of the initial fill 
with VOL and at least once every 12 calendar months thereafter.
    (iii) If any source ceases to store VOL for a period of 12 calendar 
months or more, subsequent introduction of VOL into the storage vessel 
must be

[[Page 83327]]

considered an initial fill for the purposes of paragraphs (b)(1)(i) and 
(b)(1)(ii) of this section.
    (2) Determine gap widths and areas in the primary and secondary 
seals individually by the following procedures:
    (i) Measure seal gaps, if any, at one or more floating roof levels 
when the roof is floating off the roof supports.
    (ii) Measure seal gaps around the entire circumference of the 
storage vessel in each place where a 0.125-inch (0.32-centimeter (cm)) 
diameter uniform probe passes freely (without forcing or binding 
against seal) between the seal and the wall of the storage vessel and 
measure the circumferential distance of each such location.
    (iii) The total surface area of each gap described in paragraph 
(b)(2)(ii) of this section must be determined by using probes of 
various widths to measure accurately the actual distance from the 
storage vessel wall to the seal and multiplying each such width by its 
respective circumferential distance.
    (3) Add the gap surface area of each gap location for the primary 
seal and the secondary seal individually and divide the sum for each 
seal by the nominal diameter of the storage vessel and compare each 
ratio to the respective standards in paragraph (b)(4) of this section.
    (4) Except as provided in paragraph (b)(5) of this section, make 
necessary repairs or empty the storage vessel within 45 days of 
identification in any inspection failure as specified in paragraphs 
(b)(4)(i) through (iii) of this section.
    (i) For primary seals, any deviation of the requirements in 
paragraphs (b)(4)(i)(A) through (D) of this section is an inspection 
failure.
    (A) The accumulated area of gaps between the storage vessel wall 
and the mechanical shoe or liquid-mounted primary seal must not exceed 
10 square inches (in\2\) per foot of storage vessel diameter (212 
square centimeters (cm\2\) per meter of storage vessel diameter).
    (B) The maximum width of any portion of any gap must not exceed 1.5 
inches (3.81 cm).
    (C) If a mechanical shoe seal is used, one end of the mechanical 
shoe is to extend into the stored liquid, and the other end is to 
extend a minimum vertical distance of 2 feet (61 cm) above the stored 
liquid surface.
    (D) There are to be no holes, tears, or other openings in the shoe, 
seal fabric, or seal envelope.
    (ii) For secondary seals, any deviation of the requirements in 
paragraphs (b)(4)(ii)(A) through (D) of this section is an inspection 
failure.
    (A) The secondary seal is to be installed above the primary seal so 
that it completely covers the space between the roof edge and the 
storage vessel wall except for allowed gaps as provided in paragraphs 
(b)(4)(ii)(B) and (C) of this section.
    (B) The accumulated area of gaps between the storage vessel wall 
and the secondary seal must not exceed 1 in\2\ per foot (21.2 cm\2\ per 
meter) of storage vessel diameter.
    (C) The maximum width of any portion of any gap must not exceed 0.5 
inches (1.27 cm).
    (D) There are to be no holes, tears, or other openings in the seal 
or seal fabric.
    (iii) For roof fittings (e.g., vacuum breaker/automatic bleeder 
vents and rim vents, gauge hatch/sample wells, access hatches, 
guidepoles, ladders, and emergency roof drains), any deviation of the 
requirements in paragraphs (b)(4)(iii)(A) through (D) of this section 
is an inspection failure.
    (A) Each opening in an external floating roof except for vacuum 
breaker/automatic bleeder vents and the rim vents provides a projection 
below the liquid surface.
    (B) Vacuum breaker/automatic bleeder vents and rim vents are 
equipped with a gasket and are closed with no visible gaps when the 
roof is floating.
    (C) The gauge hatch/sample well, access hatch, and gauge float must 
have a gasketed cover and closed with no visible gaps.
    (D) There are to be no tears or visible defects of sleeves, wipers, 
or fabric covers used to control emissions from a roof fitting.
    (5) If a failure that is detected as specified in paragraph (b)(4) 
of this section cannot be repaired within 45 days and if the storage 
vessel cannot be emptied within 45 days, you may request a 30-day 
extension from the Administrator. Such extension request must include a 
demonstration of unavailability of alternate storage capacity and a 
specification of a schedule that will assure that the control equipment 
will be repaired or the storage vessel will be emptied as soon as 
possible.
    (6) Notify the Administrator, as specified in Sec.  60.116c(b)(2), 
30 days in advance of any gap measurements required by paragraph (b)(1) 
of this section to afford the Administrator the opportunity to have an 
observer present.
    (7) Visually inspect the external floating roof, primary seal, 
secondary seal, and fittings each time the vessel is emptied and 
degassed.
    (i) If the external floating roof has defects, the primary seal has 
holes, tears, or other openings in the seal or the seal fabric, the 
secondary seal has holes, tears, or other openings in the seal or the 
seal fabric, covers have visible openings or missing or torn gaskets, 
or there are tears or other visible defects in flexible covers, 
sleeves, wipers, or other fitting controls, you must repair the items 
as necessary so that none of the conditions specified in this paragraph 
(b)(7)(i) exist before filling or refilling the storage vessel with 
VOL.
    (ii) For each inspection required by paragraph (b)(7) of this 
section, notify the Administrator as specified in Sec.  60.116c(b)(1) 
at least 30 days prior to the inspection of each storage vessel to 
afford the Administrator the opportunity to inspect the storage vessel.
    (8) You must equip each affected storage vessel that has an 
external floating roof with an alarm system that provides a visual or 
audible signal that alerts the operator when the external floating roof 
is approaching the landed height and that provides a separate visual or 
audible signal to alert the operator when the roof has landed. The roof 
is considered landed when the floating roof first rests on supports or 
when the vacuum breaker/automatic bleeder vent begins to open, 
whichever is first (for example, when using a leg-actuated vent that 
triggers the vent prior to resting on the roof supports).
    (c) Requirements for closed vent systems routed to a control 
device, fuel gas system, or process. For each source that is equipped 
with a closed vent system and routes to a control device, fuel gas 
system, or process to meet the requirements in Sec.  60.112c(d), you 
must conduct performance testing and monitoring of the control device 
as specified in paragraph (c)(1) of this section, conduct monitoring 
and inspections of the closed vent system as specified in paragraph 
(c)(2) of this section, repair leaks as specified in paragraph (c)(3) 
of this section, and develop a monitoring plan as specified in 
paragraph (c)(4) of this section.
    (1) For each control device used to meet the requirements in Sec.  
60.112c(d), you must comply with the requirements in paragraphs 
(c)(1)(i) through (iv) of this section, as applicable.
    (i) For each enclosed combustion device or flare, you must install, 
calibrate, maintain, and operate a backpressure regulator valve 
calibrated to open at the minimum pressure set point corresponding to 
the minimum inlet gas flow rate. The set point must be consistent with 
manufacturer specifications for minimum flow or pressure and must be 
supported by an

[[Page 83328]]

engineering evaluation. At least annually, you must confirm that the 
backpressure regulator valve set point is correct and consistent with 
the engineering evaluation and manufacturer specifications and that the 
valve fully closes when not in the open position.
    (ii) For each control device other than a flare, except as 
specified in paragraph (c)(1)(iii) of this section, you must conduct a 
performance test as specified in paragraphs (c)(1)(ii)(A) through (E) 
of this section not later than 180 days after becoming subject to Sec.  
60.112c(d). You must conduct subsequent performance tests within 60 
calendar months after each previous performance test. Submit the 
results of all performance tests following the procedures in Sec.  
60.116c(e).
    (A) Each performance test must demonstrate that the control device 
achieves greater than or equal to the required control device 
performance level specified in Sec.  60.112c(d)(3). Performance tests 
must be conducted under such conditions as the Administrator specifies 
based on representative performance of the affected source for the 
period being tested. You may not conduct performance tests during 
periods of malfunction. You must record the process information that is 
necessary to document operating conditions during the test and include 
in such record an explanation to support that such conditions represent 
the entire range of normal operation, including operational conditions 
for maximum emissions if such emissions are not expected during maximum 
production. You must make available to the Administrator such records 
as may be necessary to determine the conditions of performance tests.
    (B) You must conduct a minimum of three test runs. Each test run 
must be at least 1 hour long.
    (C) The following methods in appendix A to this part, except as 
provided in Sec.  60.8(b), must be used as reference methods to 
determine compliance with the percent reduction requirement.
    (1) Method 1 or 1A of appendix A-1 to this part, as appropriate, 
for selection of the sampling sites. Sampling sites must be located at 
the inlet of the first control device and at the outlet of the final 
control device to determine compliance with a control device percent 
reduction requirement.
    (2) Method 2, 2A, 2C, or 2D of appendix A-1 to this part, as 
appropriate to determine the gas volumetric flow rate.
    (3) Method 25A of appendix A-7 to this part. Use propane as the 
calibration gas. You must use Method 4 of appendix A-3 to this part to 
convert the Method 25A of appendix A-7 results to a dry basis.
    (D) You must use the procedures in paragraphs (c)(1)(ii)(D)(1) and 
(2) of this section to calculate percent reduction efficiency.
    (1) You must compute the mass rate of TOC using the following 
equations:

E<INF>i</INF> = K<INF>2</INF>C<INF>i</INF>M<INF>p</INF>Q<INF>i</INF>
E<INF>o</INF> = K<INF>2</INF>C<INF>o</INF>M<INF>p</INF>Q<INF>o</INF>
Equations 1 and 2 to Paragraph (c)(1)(ii)(D)(1)
Where:

E<INF>i</INF>, E<INF>o</INF> = Mass rate of TOC at the inlet and 
outlet of the control device, respectively, dry basis, kilograms per 
hour.
K<INF>2</INF> = Constant, 2.494 x 10<SUP>-6</SUP> (parts per 
million) (gram-mole per standard cubic meter) (kilogram/gram) 
(minute/hour), where standard temperature (gram-mole per standard 
cubic meter) is 20 degrees Celsius.
C<INF>i</INF>, C<INF>o</INF> = Concentration of TOC, as propane, of 
the gas stream as measured by Method 25A of appendix A-7 to this 
part at the inlet and outlet of the control device, respectively, 
dry basis, parts per million by volume.
M<INF>p</INF> = Molecular weight of propane, 44.1 gram/gram-mole.
Q<INF>i</INF>, Q<INF>o</INF> = Flowrate of gas stream at the inlet 
and outlet of the control device, respectively, dry standard cubic 
meter per minute.

    (2) You must calculate the percent reduction in TOC as follows:
    [GRAPHIC] [TIFF OMITTED] TR15OC24.000
    
Equation 3 to Paragraph (c)(1)(ii)(D)(2)
Where:
R<INF>cd</INF> = Control efficiency of control device, percent.
E<INF>i</INF> = Mass rate of TOC at the inlet to the control device 
as calculated under paragraph (c)(1)(ii)(D)(1) of this section, 
kilograms per hour.
E<INF>o</INF> = Mass rate of TOC at the outlet of the control 
device, as calculated under paragraph (c)(1)(ii)(D)(1) of this 
section, kilograms per hour.

    (E) Except as provided in paragraph (c)(1)(ii)(E)(5) of this 
section, you must establish the applicable operating parameter limit as 
specified in paragraphs (c)(1)(ii)(E)(1) through (3) of this section by 
calculating the value(s) as the arithmetic average of operating 
parameter measurements recorded during the three test runs conducted 
for the most recent performance test (the average of the test run 
averages). You may operate outside of the established operating 
parameter limit(s) during subsequent performance tests in order to 
establish new operating limits. You must include the updated operating 
limits with the performance test results submitted to the Administrator 
pursuant to Sec.  60.116c(e). Upon establishment of a new operating 
limit, you must thereafter operate under the new operating limit. You 
must demonstrate compliance with your operating parameter according to 
paragraph (c)(1)(ii)(E)(4) of this section.
    (1) If you use an enclosed combustion device, a boiler, or a 
process heater other than those specified in paragraph (c)(1)(iii) of 
this section to control emissions, you must set a minimum firebox 
temperature limit during the performance test. You must continuously 
monitor the firebox temperature with a temperature monitoring device 
installed in the firebox or in the ductwork immediately downstream from 
the firebox in a position before any substantial heat exchange occurs 
and equipped with a continuous recorder that records a reading at least 
once every 15 minutes. The monitoring device must have a minimum 
accuracy of <plus-minus>1 percent of the temperature being monitored in 
degrees Celsius, or <plus-minus>2.5 degrees Celsius, whichever value is 
greater.
    (2) If you use a catalytic incinerator other than those specified 
in paragraph (c)(1)(iii) of this section to control emissions, you must 
set a minimum temperature limit on the temperature at the inlet of the 
catalyst bed and a minimum temperature limit on the temperature 
difference between the catalyst bed outlet and inlet. You must 
continuously monitor the temperatures with a temperature monitoring 
device equipped with a continuous recorder that records a reading at 
least once every 15 minutes. The device must be capable of monitoring 
temperature at two locations and have a minimum accuracy of <plus-
minus>1 percent of the temperature being monitored in degrees Celsius, 
or <plus-minus>2.5 degrees Celsius, whichever value is greater. You 
must install one temperature sensor in the vent stream at the nearest 
feasible point to the catalyst bed inlet, and you must install a second 
temperature sensor in the vent stream at the nearest feasible point to 
the catalyst bed outlet. You must install the temperature sensor at a 
location representative of the firebox temperature.
    (3) If you use a control device other than a flare or other than a 
device listed in paragraphs (c)(1)(ii)(E)(1), (c)(1)(ii)(E)(2), 
(c)(1)(ii)(E)(5), or (c)(1)(iii) to control emissions, you must submit 
the operating parameters you plan to monitor in the performance test

[[Page 83329]]

notice you provide to the Administrator pursuant to Sec.  60.8(d).
    (4) Using the continuous monitoring system (CMS) data, you must 
calculate the hourly average of each operating parameter. You must 
demonstrate compliance by maintaining the operating parameter at or 
above the minimum operating parameter limit on a 3-hour rolling average 
basis. For each hour, calculate the hourly value of the operating 
parameter from your CMS. Average the three most recent hours of data to 
determine the 3-hour average. Determine the 3-hour rolling average by 
recalculating the 3-hour average each hour. You must not include 
periods of data collected during monitoring system breakdowns, repairs, 
maintenance periods, instrument adjustments, or checks to maintain 
precision and accuracy in the operating parameter averages.
    (5) For enclosed combustion devices for which you elect to comply 
with the flare requirements in Sec.  60.112c(d)(5), you must comply 
with the monitoring provisions in paragraph (c)(1)(iv) of this section 
instead of paragraphs (c)(1)(ii)(E)(1) through (4) of this section.
    (iii) No performance test is required for the control devices 
identified in paragraphs (c)(1)(iii)(A) through (C) of this section.
    (A) A boiler or process heater with a design heat input capacity of 
44 megawatts (150 million British thermal units per hour) or greater.
    (B) A boiler or process heater into which the vent stream is 
introduced with the primary fuel.
    (C) A boiler, process heater, or incinerator burning hazardous 
waste, which is regulated under 40 CFR part 63, subpart EEE; part 264; 
part 265; or part 266.
    (iv) For each source that is equipped with a closed vent system and 
a flare to meet the requirements in Sec.  60.112c(d) or enclosed 
combustion device electing to comply with the requirements in Sec.  
60.112c(d)(5), you must conduct visible emission observations as 
specified in paragraph (c)(1)(iv)(A) of this section and install, 
operate, and maintain CMS for flares following the requirements 
specified in 40 CFR 63.671 and as specified in paragraphs (c)(1)(iv)(B) 
and (C) of this section.
    (A) If visible emissions are observed for more than 1 continuous 
minute during normal duties, visible emissions observation using Method 
22 of appendix A-7 to this part must be conducted for 2 hours or until 
5-minutes of visible emissions are observed.
    (B) Substitute ``pilot flame or flare flame'' for each occurrence 
of ``pilot flame.''
    (C) As an alternative to determining the flare tip velocity rate 
for each 15-minute block to determine compliance with the flare tip 
velocity operating limit as specified in 40 CFR 63.670(k)(2), you may 
elect to conduct a one-time flare tip velocity operating limit 
compliance assessment as provided in paragraphs (c)(1)(iv)(C)(1) 
through (4) of this section. If the flare or storage vessel control 
configurations change (e.g., flare tip modified or additional storage 
vessel or other sources are added for which vapors are directed to the 
flare), you must repeat this one-time assessment based on the new 
configuration.
    (1) Determine the unobstructed cross-sectional area of the flare 
tip, in units of square feet, as specified in 40 CFR 63.670(k)(1).
    (2) Determine the maximum flow rate, in units of cubic feet per 
second, based on the maximum cumulative loading rate for a 15-minute 
block period considering maximum filling rates for all storage vessel 
affected facilities controlled by the flare and, if applicable, 
considering the maximum release pressure of any other vapors directed 
to the flare.
    (3) Calculate the maximum flare tip velocity as the maximum flow 
rate from paragraph (c)(1)(iv)(C)(2) of this section divided by the 
unobstructed cross-sectional area of the flare tip from paragraph 
(c)(1)(iv)(C)(1) of this section.
    (4) Demonstrate that the maximum flare tip velocity as calculated 
in paragraph (c)(1)(iv)(C)(3) of this section is less than 60 feet per 
second.
    (2) For each closed vent system, you must conduct the instrument 
monitoring in paragraphs (c)(2)(i) through (iii) of this section. You 
must conduct the initial instrument monitoring within 180 days of an 
affected facility being connected to the closed vent system. Subsequent 
instrument inspections must be conducted within 365 days of the 
previous inspection. Visual, audible, and olfactory inspections must be 
conducted quarterly.
    (i) Conduct instrument monitoring using the procedures in Method 21 
of appendix A-7 to this part. The detection instrument must meet the 
performance criteria of Method 21 of appendix A-7, except that the 
instrument response factor criteria in section 8.1.1 of Method 21 of 
appendix A-7 must be for the average composition of the fluid and not 
for each individual organic compound in the stream. For streams that 
contain nitrogen, air, water, or other inerts that are not organic VOC, 
the representative stream response factor must be determined on an 
inert-free basis. The instrument reading that defines a leak is 500 
ppmv (as methane). The instrument shall be calibrated before use each 
day of its use by the procedures specified in Method 21 of appendix A-
7. The calibration gases in paragraphs (c)(2)(i)(A) and (B) of this 
section must be used. The drift assessment specified in paragraph 
(c)(2)(i)(C) of this section must be performed at the end of each 
monitoring day.
    (A) Zero air (less than 10 ppm of hydrocarbon in air).
    (B) A mixture of methane in air at a concentration of approximately 
500 ppmv.
    (C) At the end of each monitoring day, check the instrument using 
the same calibration gas that was used to calibrate the instrument 
before use. Follow the procedures specified in Method 21 of appendix A-
7 to this part, section 10.1, except do not adjust the meter readout to 
correspond to the calibration gas value. If multiple scales are used, 
record the instrument reading for each scale used. Divide the 
arithmetic difference of the initial and post-test calibration response 
by the corresponding calibration gas value for each scale and multiply 
by 100 to express the calibration drift as a percentage. If a 
calibration drift assessment shows a negative drift of more than 10 
percent, then re-monitor all equipment monitored since the last 
calibration with instrument readings between the leak definition and 
the leak definition multiplied by (100 minus the percent of negative 
drift) divided by 100. If any calibration drift assessment shows a 
positive drift of more than 10 percent from the initial calibration 
value, then, at the owner/operator's discretion, all equipment with 
instrument readings above the leak definition and below the leak 
definition multiplied by (100 plus the percent of positive drift) 
divided by 100 monitored since the last calibration may be re-
monitored.
    (ii) Any parts of the closed vent system that are designated as 
unsafe to inspect are exempt from the inspection requirements of 
paragraph (c)(2)(i) of this section if the conditions of paragraphs 
(c)(2)(ii)(A) and (B) of this section are met.
    (A) The owner or operator determines that the equipment is unsafe-
to-inspect because inspecting personnel would be exposed to an imminent 
or potential danger as a consequence of complying with paragraph 
(c)(2)(i) of this section; and
    (B) The owner or operator has a written plan that requires 
inspection of

[[Page 83330]]

the equipment as frequently as practical during safe-to-inspect times. 
Inspection is not required more than once annually.
    (iii) Any parts of the closed vent system that are designated as 
difficult-to-inspect are exempt from the inspection requirements of 
paragraph (c)(2)(i) of this section if the provisions of paragraphs 
(c)(2)(iii)(A) and (B) of this section apply.
    (A) The owner or operator determines that the equipment cannot be 
inspected without elevating the inspecting personnel more than 2 meters 
(7 feet) above a support surface; and
    (B) The owner or operator has a written plan that requires 
inspection of the equipment at least once every 60 calendar months.
    (3) Leaks, as indicated by an instrument reading greater than 500 
ppmv or emissions detected by visible, audible, and olfactory methods, 
shall be repaired as soon as practical following the requirements 
outlined in paragraphs (c)(3)(i) and (ii) of this section.
    (i) Except as allowed by paragraph (c)(3)(ii) of this section, a 
first attempt at repair shall be made no later than 5 days after the 
leak is detected. Repairs shall be completed no later than 15 days 
after the leak is detected or at the beginning of the next introduction 
of vapors to the system, whichever is later.
    (ii) Delay of repair of a closed vent system for which leaks have 
been detected is allowed if repair within 15 days after a leak is 
detected is technically infeasible or unsafe or if the owner or 
operator determines that emissions resulting from immediate repair 
would be greater than the emissions likely to result from delay of 
repair. Repair of such equipment shall be completed as soon as 
practical.
    (4) You must develop a monitoring plan that covers each CMS used to 
demonstrate continuous compliance for your control device as outlined 
in paragraphs (c)(4)(i) and (ii) of this section. You must install, 
calibrate, operate, and maintain each CMS in accordance with the 
procedures in your monitoring plan.
    (i) For each control device other than those specified in paragraph 
(c)(4)(ii) of this section, your monitoring plan must contain the 
information required in paragraphs (c)(4)(i)(A) through (G) of this 
section.
    (A) The parameter to be monitored and the operating limit for the 
parameter.
    (B) Sampling interface (e.g., thermocouple) location such that the 
monitoring system will provide representative measurements.
    (C) Description of the monitoring system specifications, including 
the detector signal analyzer, data acquisition, and calculations.
    (D) Equipment performance checks, system accuracy audits, or other 
audit procedures, including the information in paragraphs 
(c)(4)(i)(D)(1) through (4) of this section.
    (1) You must conduct the CMS equipment performance checks, system 
accuracy audits, or other audit procedures specified in the monitoring 
plan at least once every 12 calendar months.
    (2) You must also conduct calibration checks following any period 
of more than 24 hours throughout which the sensor exceeded the 
manufacturer's specified maximum range unless you install a new sensor.
    (3) At least quarterly, you must inspect all components for 
integrity and all electrical connections for continuity, oxidation, and 
galvanic corrosion, unless you use a redundant CMS.
    (4) Daily checks for indications that the system is responding.
    (E) Description of how periods of data collected during CMS 
breakdowns, out-of-control periods, repairs, maintenance periods, 
instrument adjustments, or checks to maintain precision and accuracy, 
calibration checks, and zero (low-level), mid-level (if applicable), 
and high-level adjustments will be excluded from operating parameter 
averages.
    (F) Ongoing operation and maintenance procedures.
    (G) Ongoing recordkeeping procedures.
    (ii) For each flare or enclosed combustion device for with you 
elect to comply with the flare provisions in Sec.  60.112c(d)(5), your 
monitoring plan must contain the information required by 40 CFR 
63.671(b).
    (d) Requirements for determining maximum true vapor pressure. For 
each affected storage vessel, you must determine the maximum true vapor 
pressure of the stored VOL according to the requirements specified in 
paragraphs (d)(1) and (2) of this section. For storage vessels operated 
above or below ambient temperatures, the maximum true vapor pressure is 
calculated based upon the highest expected calendar-month average of 
the storage temperature. For storage vessels operated at ambient 
temperatures, the maximum true vapor pressure is calculated based upon 
the maximum local monthly average ambient temperature as reported by 
the National Weather Service.
    (1) Prior to the initial filling of the storage vessel or to the 
refilling of the storage vessel with a new VOL, the highest maximum 
true vapor pressure for the range of anticipated liquids to be stored, 
including mixtures for which you can define the range of concentrations 
for constituents in the mixture or with a known maximum Reid vapor 
pressure, must be determined using any one of the methods described in 
paragraphs (d)(1)(i) through (iv) of this section.
    (i) As obtained from standard reference texts.
    (ii) ASTM D6377-20 (incorporated by reference; see Sec.  60.17). 
Perform the method using a vapor-to-liquid ratio of 4:1, which is 
expressed in the method as VPCR.
    (iii) ASTM D6378-22 (incorporated by reference; see Sec.  60.17). 
Perform the method using a vapor-to-liquid ratio of 4:1.
    (iv) As measured by an appropriate method as approved by the 
Administrator.
    (2) For each affected storage vessel storing a mixture of 
indeterminate composition or a mixture of unknown variable composition, 
the initial determination of the vapor pressure required by paragraph 
(d)(1) of this section must be a physical test using one of the methods 
specified in paragraphs (d)(1)(ii) through (iv) of this section. 
Additional physical tests using one of the methods specified in 
paragraphs (d)(1)(ii) through (iv) of this section are required at 
least once every 6 calendar months thereafter as long as the measured 
vapor pressure remains below the applicable thresholds in Sec.  
60.110c(c)(1), (c)(2), (d)(1), or (d)(2). If the vapor pressure 
measured under this paragraph (d)(2) exceeds the threshold defined in 
Sec.  60.110c(c)(1), (c)(2), (d)(1), or (d)(2) you must meet the 
requirements in Sec.  60.112c and the corresponding requirements in 
Sec. Sec.  60.113c through 60.116c. If the storage vessel does not have 
controls meeting the requirements in Sec.  60.112c, the storage vessel 
must be emptied and taken out of service until controls meeting the 
requirements in Sec.  60.112c can be installed. Upon compliance with 
the provisions in Sec.  60.112c, no additional vapor pressure 
monitoring is required.


Sec.  60.114c  Alternative means of emission limitation.

    (a) If, in the Administrator's judgment, an alternative means of 
emission limitation will achieve a reduction in emissions at least 
equivalent to the reduction in emissions achieved by the applicable 
requirement in Sec.  60.112c, the Administrator will publish in the 
Federal Register a

[[Page 83331]]

document permitting the use of the alternative means for purposes of 
compliance with that requirement.
    (b) Any document under paragraph (a) of this section will be 
published only after notice and an opportunity for a hearing.
    (c) Any person seeking permission under this section must submit to 
the Administrator a written application including either:
    (1) An actual emissions test that uses a full-sized or scale-model 
storage vessel that accurately collects and measures all VOC emissions 
from a given control device and that accurately simulates wind and 
accounts for other emission variables such as temperature and 
barometric pressure; or
    (2) An engineering evaluation that the Administrator determines is 
an accurate method of determining equivalence.
    (d) The Administrator may condition the permission on requirements 
that may be necessary to ensure operation and maintenance to achieve 
the same emission reduction as specified in Sec.  60.112c.


Sec.  60.115c  Recordkeeping requirements.

    (a) Except as otherwise specified in paragraphs (b) through (d) of 
this section, you must keep copies of all records required by this 
section and all reports required under Sec.  60.116c for at least 5 
years.
    (b) For each storage vessel affected facility as specified in Sec.  
60.110c(a), you must keep readily accessible records for the life of 
the source showing the dimension of the storage vessel and an analysis 
showing the capacity of the storage vessel.
    (c) Except as provided in paragraphs (c)(1) and (2) of this 
section, for each storage vessel affected facility under this subpart, 
you must maintain a record of the VOL currently stored, including a 
description of the VOL stored, the date when the VOL was first stored 
in the storage vessel, and the maximum true vapor pressure of that VOL.
    (1) For each vessel storing a mixture of indeterminate or variable 
composition that meets the requirements for vapor pressure measurement 
at least once every 6 calendar months in Sec.  60.113c(d), you must 
maintain records of each vapor pressure measurement for 5 years.
    (2) Each vessel equipped with a closed vent system routed to a 
control device, fuel gas system, or process meeting the specification 
of Sec.  60.112c(d) is exempt from the requirements of paragraph (c) of 
this section.
    (d) For each storage vessel as specified in Sec.  60.112c(a), you 
must keep records as required in paragraphs (d)(1) through (5) of this 
section, as applicable depending upon the control equipment installed 
to meet the requirements of Sec.  60.112c.
    (1) After installing control equipment for an internal floating 
roof to meet the provisions in Sec.  60.112c(b), you must keep the 
following records.
    (i) Keep a record of each inspection performed as required by Sec.  
60.113c(a)(1), (a)(2)(i), and (a)(2)(ii). Each record must identify the 
storage vessel on which the inspection was performed and must contain 
the date the vessel was inspected and the observed condition of each 
component of the control equipment (seals, internal floating roof, and 
fittings).
    (ii) For each LEL monitoring event, keep records as specified in 
paragraphs (a)(1)(ii)(A) through (I) of this section.
    (A) Date and time of the LEL monitoring, and the storage vessel 
being monitored.
    (B) A description of the monitoring event (annual monitoring 
conducted concurrent with visual inspection required under Sec.  
60.113c(a)(2)(i); re-monitoring due to high winds during annual 
monitoring; re-monitoring after repair attempt; other monitoring event 
as required by the Administrator).
    (C) Wind speed at the top of the storage vessel on the date of LEL 
monitoring.
    (D) The LEL meter manufacturer and model number used, as well as an 
indication of whether tubing was used during the LEL monitoring, and if 
so, the type and length of tubing used.
    (E) Calibration checks conducted before and after making the 
measurements, including both the span check and instrumental offset. 
This includes the hydrocarbon used as the calibration gas, the 
Certificate of Analysis for the calibration gas(es), the results of the 
calibration check, and any corrective action for calibration checks 
that do not meet the required response.
    (F) Location of the measurements and the location of the floating 
roof.
    (G) Each measurement (taken at least once every 15 seconds). The 
records should indicate whether the recorded values were automatically 
corrected using the meter's programming. If the values were not 
automatically corrected, record both the raw (as the calibration gas) 
and corrected measurements, as well as the correction factor used.
    (H) Each of the 5-minute rolling average readings.
    (I) If the vapor concentration of the storage vessel was above 25 
percent of the LEL on a 5-minute rolling average basis, a description 
of whether the floating roof was repaired, replaced, or taken out of 
service.
    (2) After installing control equipment for an external floating 
roof to meet the provisions in Sec.  60.112c(c), you must keep a record 
of each inspection and gap measurement performed as required by Sec.  
60.113c(b). The record must contain:
    (i) Identification of the storage vessel on which the inspection 
was performed;
    (ii) The date the storage vessel was inspected;
    (iii) The type of inspection [inspection with gap measurements as 
specified in Sec.  60.113c(b)(1) through (4); visual inspection as 
specified in Sec.  60.113c(b)(7)];
    (iv) The observed condition of each component of the control 
equipment (seals, internal floating roof, and fittings); and
    (v) For each inspection with gap measurements as specified in Sec.  
60.113c(b)(1) through (4):
    (A) The raw data obtained in the measurement; and
    (B) The calculations described in Sec.  60.113c(b)(2) and (b)(3).
    (3) After installing a closed vent system routed to a control 
device, fuel gas system, or process to comply with the provisions in 
Sec.  60.112c(d), you must keep the following records, as well as the 
records in paragraph (d)(4) or (5) of this section, as applicable.
    (i) The make and model of the backpressure regulator valve, date of 
installation, and inlet flow rating. Maintain records of the 
engineering evaluation and manufacturer specifications that identify 
the pressure set point corresponding to the minimum inlet gas flow 
rate, the annual confirmation that the backpressure regulator valve set 
point is correct and consistent with the engineering evaluation and 
manufacturer specifications, and the annual confirmation that the 
backpressure regulator valve fully closes when not in open position.
    (ii) The CMS monitoring plan required by Sec.  60.113c(c)(4), if 
the closed vent system is routed to a control device. Retain this plan 
for the life of the control equipment.
    (iii) Monitoring for the closed vent system conducted under Sec.  
60.113c(c)(2), including the date of inspection.
    (iv) The written plan(s) required under Sec.  60.113c(c)(2)(ii) and 
(iii) for unsafe-to-inspect and difficult-to-inspect portions of the 
closed vent system.
    (v) For each leak detected during the monitoring conducted under 
Sec.  60.113c(c)(2) and (3), you must record: the date the leak was 
detected; the location of the leak; the method used to detect the leak 
(Method 21 of appendix

[[Page 83332]]

A-7 to this part or visible, audible, and olfactory methods); and the 
maximum concentration reading obtained by Method 21 of appendix A-7, if 
applicable. For each repair attempt, you must record: the date of each 
repair attempt; the actions taken to repair the leak during each repair 
attempt; and date the repair was completed. If the repair is delayed, 
you must record the reason for the delay and the date you expect to 
complete the repair.
    (vi) For each bypass line, maintain a record of the following, as 
applicable: readings from the flow indicator; each inspection of the 
seal or closure mechanism; the date and time of each instance when the 
seal mechanism is broken, the bypass line valve position has changed, 
or the key for a lock-and-key type lock has been checked out.
    (vii) For each pressure relief device or vacuum breaking device on 
a storage vessel or closed vent system required to be monitored 
according to Sec.  60.112c(d)(1)(iii) or (d)(2)(iii): the device type; 
the monitoring device or system used for the device; data from the 
device or system indicating whether a pressure release occurred; and 
the date, time, and duration of each pressure release, if applicable.
    (4) After installing a closed vent system routed to a control 
device other than a flare or enclosed combustion device electing to 
comply with Sec.  60.112c(d), you must keep the following records.
    (i) Each performance test.
    (ii) All CMS performance checks, audits, maintenance, and repairs.
    (iii) The hourly values recorded by the CMS and all 3-hour rolling 
averages.
    (iv) The periods when the CMS is not operational.
    (5) After installing a closed vent system routed to a flare to 
comply with Sec.  60.112c(d) or an enclosed combustion device for which 
you elected to comply with Sec.  60.112c(d)(5), you must keep the 
following records.
    (i) Pilot flame or flare flame monitoring as specified in 
paragraphs (d)(5)(i)(A) and (B) of this section.
    (A) The output of the monitoring device used to detect the presence 
of a pilot flame as required in 40 CFR 63.670(b). Retain these records 
for a minimum of 2 years.
    (B) Each 15-minute block during which there was at least 1 minute 
that no pilot flame was present when VOL vapors were routed to the 
flare. Each record must identify the start and end time and date of 
each 15-minute block.
    (ii) Visible emissions observations as specified in paragraphs 
(d)(5)(ii)(A) through (B) of this section, as applicable.
    (A) If visible emissions observations are performed using Method 22 
of appendix A-7 to this part, the record must identify the date, the 
start and end time of the visible emissions observation, and the number 
of minutes for which visible emissions were observed during the 
observation. If the owner or operator performs visible emissions 
observations more than one time during a day, include separate records 
for each visible emissions observation performed.
    (B) For each 2-hour period for which visible emissions are observed 
for more than 5 minutes in 2 consecutive hours but visible emissions 
observations according to Method 22 of appendix A-7 to this part were 
not conducted for the full 2-hour period, the record must include the 
date, the start and end time of the visible emissions observation, and 
an estimate of the cumulative number of minutes in the 2-hour period 
for which emissions were visible based on best information available to 
the owner or operator.
    (iii) Each 15-minute block period during which operating values are 
outside of the applicable operating limits specified in 40 CFR 
63.670(d) through (f) when vapors from a storage vessel affected 
facility are directed to the flare for at least 15-minutes identifying 
each specific operating limit that was not met.
    (iv) The 15-minute block average cumulative flows for the enclosed 
combustion device vent gas or flare vent gas and, if applicable, total 
steam, perimeter assist air, and premix assist air specified to be 
monitored under 40 CFR 63.670(i), along with the date and start and end 
time for the 15-minute block. If multiple monitoring locations are used 
to determine cumulative vent gas flow, total steam, perimeter assist 
air, and premix assist air, retain records of the 15-minute block 
average flows for each monitoring location for a minimum of 2 years, 
and retain the 15-minute block average cumulative flows that are used 
in subsequent calculations for a minimum of 5 years. If pressure and 
temperature monitoring is used, retain records of the 15-minute block 
average temperature, pressure and molecular weight of the flare vent 
gas, enclosed combustion device vent gas, or assist gas stream for each 
measurement location used to determine the 15-minute block average 
cumulative flows for a minimum of 2 years, and retain the 15-minute 
block average cumulative flows that are used in subsequent calculations 
for a minimum of 5 years.
    (v) The flare vent gas or enclosed combustion device vent gas 
compositions specified to be monitored under 40 CFR 63.670(j). Retain 
records of individual component concentrations from each compositional 
analyses for a minimum of 2 years. If an NHV<INF>vg</INF> analyzer is 
used, retain records of the 15-minute block average values for a 
minimum of 5 years, as well as records of quality assurance activities 
conducted on the analyzer and any cylinder gas certificates. If you 
demonstrate your gas streams have consistent composition using the 
provisions in 40 CFR 63.670(j)(6), retain records of the current 
application for which you are using for as long as you use the fixed 
NHV<INF>vg</INF> as determined using the provisions in 40 CFR 
63.670(j)(6).
    (vi) Each 15-minute block average operating parameter calculated 
following the methods specified in 40 CFR 63.670(k) through (n), as 
applicable.
    (vii) All periods during which you did not perform monitoring 
according to the procedures in 40 CFR 63.670(g), (i), and (j) as 
applicable. Note the start date, start time, and duration in minutes 
for each period.
    (viii) If you conduct a one-time flare tip velocity operating limit 
compliance assessment according to Sec.  60.113c(c)(1)(iv)(C), a copy 
of the assessment, including all calculations for as long as you use 
this compliance method.
    (ix) For each parameter monitored using a CMS, retain the records 
specified in paragraphs (d)(5)(ix)(A) through (C) of this section, as 
applicable:
    (A) For each deviation, record the start date and time, duration, 
cause, and corrective action taken.
    (B) For each period when there is a CMS outage or the CMS is out of 
control, record the start date and time, duration, cause, and 
corrective action taken.
    (C) Each inspection or calibration of the CMS including a unique 
identifier, make, and model number of the CMS, and date of calibration 
check.
    (x) For an enclosed combustion device for which you elected to 
comply with Sec.  60.112c(d)(5), you must also keep a copy of each 
performance test.
    (e) If you are required to meet the degassing requirements in Sec.  
60.112c(a)(3), you must maintain records necessary to demonstrate 
compliance with the requirements in Sec.  60.112c(e) including, if 
appropriate, records of existing standard site procedures used to empty 
and degas (deinventory) equipment for safety purposes.

[[Page 83333]]

Sec.  60.116c  Reporting requirements.

    (a) Initial notification requirements. You must submit initial 
notifications to the Administrator within 60 days after October 15, 
2024 or within 60 days after becoming an affected storage vessel, 
whichever is later. Once the report template for this subpart has been 
available on the Compliance and Emissions Data Reporting Interface 
(CEDRI) website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, you must submit all subsequent initial 
notifications using the appropriate electronic report template on the 
CEDRI website for this subpart and following the procedure specified in 
paragraph (f) of this section. The date report templates become 
available will be listed on the CEDRI website. For each storage vessel 
affected facility subject to the standards in Sec.  60.112c, include 
the following information in the initial notification:
    (1) The following general facility information:
    (i) Facility name;
    (ii) Facility physical address, including city, county, State, and 
zip code;
    (iii) Latitude and longitude of facility's physical location. 
Coordinates must be in decimal degrees with at least five decimal 
places; and
    (iv) The following information for the facility contact person:
    (A) Name;
    (B) Mailing address, including city, county, State, and zip code;
    (C) Telephone number; and
    (D) Email address.
    (2) Identification of the storage vessel(s) subject to this 
subpart.
    (3) Capacity (in gallons) of each storage vessel.
    (4) Maximum true vapor pressure of the liquid stored (in psia) in 
each storage vessel.
    (5) Indication of the standards for which the storage vessel 
complies [Sec. Sec.  60.112c(b); 60.112c(c); 60.112c(d); 60.112c(e)].
    (6) If you route emissions to a control device, specify the design 
of the storage vessel and closed vent system (i.e., storage vessel 
designed according to Sec.  60.112c(d)(1)(i); or closed vent system 
designed according to Sec.  60.112c(d)(1)(ii)), the type of control 
device (i.e., enclosed combustion device complying with temperature 
operating limit; enclosed combustion device electing to comply with 
Sec.  60.112c(d)(5); process heater or boiler; catalytic incinerator; 
flare, or other control device (specify)).
    (7) If you route emissions to a process, submit the information 
specified in Sec.  60.112c(d)(6)(ii) and (iii).
    (8) If you route emissions to a fuel gas system, as specified in 
Sec.  60.112c(d)(6)(iv), submit a statement that the emission stream is 
connected to the fuel gas system.
    (b) Other notifications. Submit notifications for filling and 
refilling an affected storage vessel and for conducting gap 
measurements as specified in paragraphs (b)(1) and (2) of this section.
    (1) As specified in Sec.  60.113c(a)(4) and (b)(7)(ii), you must 
notify the Administrator at least 30 days prior to inspection of each 
storage vessel for which an inspection is required by Sec.  
60.113c(a)(1), (a)(2)(ii) or (b)(7) to afford the Administrator the 
opportunity to have an observer present. Submit the notification using 
CEDRI as specified in paragraph (f) of this section. If the inspection 
required by Sec.  60.113c(a)(2)(ii) or (b)(7) is not planned and you 
could not have known about the inspection 30 days in advance of 
refilling the storage vessel, you must notify the Administrator at 
least 7 days prior to the refilling of the storage vessel. Notification 
shall be made by telephone immediately followed by written 
documentation using CEDRI demonstrating why the inspection was 
unplanned.
    (2) As specified in Sec.  60.113c(b)(6), you must notify the 
Administrator 30 days in advance of any gap measurements required by 
Sec.  60.113c(b)(1) to afford the Administrator the opportunity to have 
an observer present. Submit the notification using CEDRI as specified 
in paragraph (f) of this section. If the inspection required by Sec.  
60.113c(b)(1) is not planned and you could not have known about the 
inspection 30 days in advance of the gap measurement, you must notify 
the Administrator at least 7 days prior to the conducting the gap 
measurement. Notification must be made by telephone immediately 
followed by written documentation using CEDRI demonstrating why the gap 
measurement was unplanned.
    (c) Reporting requirements for semiannual report. You must submit 
to the Administrator semiannual reports with the applicable information 
in paragraphs (c)(1) through (12) of this section by the dates 
specified in paragraph (d) of this section. For this subpart, the 
semiannual reports supersede the excess emissions and monitoring 
systems performance report and/or summary report form required under 
Sec.  60.7. Once the report template for this subpart has been 
available on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for 1 year, you must submit all 
subsequent reports using the appropriate electronic report template on 
the CEDRI website for this subpart and following the procedure 
specified in paragraph (f) of this section. The date report templates 
become available will be listed on the CEDRI website. Unless the 
Administrator or delegated State agency or other authority has approved 
a different schedule for submission of reports, the report must be 
submitted by the deadline specified in this subpart, regardless of the 
method in which the report is submitted.
    (1) Report the following general facility information:
    (i) Facility name;
    (ii) Facility physical address, including city, county, and State;
    (iii) Latitude and longitude of facility's physical location. 
Coordinates must be in decimal degrees with at least five decimal 
places;
    (iv) The following information for the facility contact person:
    (A) Name;
    (B) Mailing address;
    (C) Telephone number; and
    (D) Email address.
    (v) Date of report and beginning and ending dates of the reporting 
period. You are no longer required to provide the date of report when 
the report is submitted via CEDRI; and
    (vi) Statement by a responsible official, with that official's 
name, title, and signature, certifying the truth, accuracy, and 
completeness of the content of the report. If your report is submitted 
via CEDRI, the certifier's electronic signature during the submission 
process replaces the requirement in this paragraph (c)(1)(vi).
    (2) For storage vessels complying with the provisions of Sec.  
60.112c(b) or (c):
    (i) Identification of the storage vessel and an indication of 
whether you comply with Sec.  60.112c(b) or (c).
    (ii) An indication whether the storage vessel was inspected during 
the reporting period, and if so, the date and type of each inspection 
conducted during the reporting period [the type of inspection shall be 
selected from the following list: initial IFR inspection according to 
Sec.  60.113c(a)(1), IFR visual inspection from fixed roof according to 
Sec.  60.113c(a)(2)(i), combined IFR visual inspection with LEL 
monitoring according to Sec.  60.113c(a)(2)(i) and (3), internal IFR 
inspection according to Sec.  60.113c(a)(2)(ii), IFR LEL monitoring 
according to Sec.  60.113c(a)(3), EFR gap measurements according to 
Sec.  60.113c(b)(1) through (4), or visual EFR inspection according to 
Sec.  60.113c(b)(7)].
    (iii) For storage vessels complying with the provisions of Sec.  
60.112c(b) that were not inspected according to

[[Page 83334]]

Sec.  60.113c(a)(2)(ii) during the reporting period, report the last 
date the storage vessel was inspected according to the provisions in 
Sec.  60.113c(a)(2)(ii).
    (3) For each failure of a visual inspection required under Sec.  
60.113c(a)(2)(i), report the information in paragraphs (c)(3)(i) 
through (iii) of this section. For each failure of LEL monitoring 
required under Sec.  60.113c(a)(3), report the information in 
paragraphs (c)(3)(i) through (iv) of this section.
    (i) Identification of the storage vessel;
    (ii) The date of the inspection;
    (iii) The nature of the defects; and
    (iv) The following information regarding the LEL monitoring 
conducted:
    (A) Date and start and end times of the LEL monitoring conducted.
    (B) Wind speed in miles per hour at the top of the storage vessel 
on the date of LEL monitoring.
    (C) The highest 5-minute rolling average reading during the 
monitoring event.
    (D) If re-monitoring was required due to excessive wind or repair 
during the visual inspection, report the information in paragraphs 
(b)(3)(iv)(A) through (C) of this section for the re-monitoring event.
    (E) Whether the floating roof was repaired, replaced, or taken out 
of VOL service. If the storage vessel was taken out of VOL service, 
report the date the storage vessel was emptied. If the floating roof 
was replaced or repaired, report the nature of and date the repair was 
made and the information in paragraphs (b)(3)(iv)(A) through (C) of 
this section for each re-monitoring conducted to confirm the repair.
    (4) For each inspection required by Sec.  60.113c(a)(2)(ii) that 
finds holes or tears in the seal or seal fabric, defects in the 
internal floating roof, or other control equipment defects listed in 
Sec.  60.113c(a)(2)(ii), report:
    (i) Identification of the storage vessel and date of inspection;
    (ii) The reason it did not meet the specifications of Sec.  
60.112c(b) or Sec.  60.113c(a)(2)(ii);
    (iii) A description of each repair made; and
    (iv) Date of repair.
    (5) For each inspection required under Sec.  60.113c(b)(1), report 
the following information:
    (i) Identification of the storage vessel and the date of the 
inspection;
    (ii) The accumulated area of gaps between the storage vessel wall 
and the primary seal (in square inches per foot of storage vessel 
diameter);
    (iii) The maximum width of any portion of any gap in the primary 
seal (in inches);
    (iv) The accumulated area of gaps between the storage vessel wall 
and the secondary seal (in square inches per foot of storage vessel 
diameter);
    (v) The maximum width of any portion of any gap in the secondary 
seal (in inches); and
    (vi) An indication whether there was an inspection failure. If 
there was an inspection failure, also include the following information 
in the report:
    (A) An indication of the type of deviation(s) [indicating all that 
apply from: Sec. Sec.  60.113c(b)(4)(i)(A), 60.113c(b)(4)(i)(B), 
60.113c(b)(4)(i)(C), 60.113c(b)(4)(i)(D), 60.113c(b)(4)(ii)(A), 
60.113c(b)(4)(ii)(B), 60.113c(b)(4)(ii)(C), 60.113c(b)(4)(ii)(D), 
60.113c(b)(4)(iii)(A), 60.113c(b)(4)(iii)(B), 60.113c(b)(4)(iii)(C), 
60.113c(b)(4)(iii)(D)]; and
    (B) The date the storage vessel was emptied or the repairs made and 
date of repair.
    (6) For each inspection required by Sec.  60.113c(b)(7) that finds 
defects as listed in Sec.  60.113c(b)(7)(i), report:
    (i) Identification of the storage vessel and date of inspection;
    (ii) The reason it did not meet the specifications of Sec.  
60.112c(c) or Sec.  60.113c(b)(7);
    (iii) A description of each repair made; and
    (iv) Date of repair.
    (7) For each landing of an internal floating roof or an external 
floating roof that triggers an alarm required by Sec.  60.113c(a)(5) or 
(b)(8), report:
    (i) Identification of the storage vessel;
    (ii) Date the roof was landed; and
    (iii) Indication of whether the roof landed because the storage 
vessel was being emptied.
    (8) After installing a closed vent system that routes to a control 
device, fuel gas system, or process to comply with Sec.  60.112c, 
report the following, as well as the information in paragraphs (c)(9) 
or (10) of this section, as applicable:
    (i) Results of annual inspections that indicate a backpressure 
regulator valve is not set correctly or does not fully close when not 
in the open position. Include the date and time of the inspection, the 
type of deviation, the corrective action taken, and the date and time 
when the backpressure regulator valve is set correctly, repaired, or 
replaced.
    (ii) For each inspection conducted under Sec.  60.113c(c)(2), 
identification of the closed vent system, the date of inspection, the 
type of inspection (Method 21 of appendix A-7 to this part or visible, 
audible, and olfactory methods) and summary result of the inspection 
(no leaks detected or leaks were detected). For each leak detected, 
provide an identification of the part of the closed vent system 
associated with the leak, the date of the first attempt at repair, and 
the date of successful repair or anticipated repair if the repair is 
delayed.
    (iii) The start date and time, duration in hours, and an estimate 
of the mass quantity in pounds of VOL released for times when flow is 
detected or emissions are diverted from the control device through a 
bypass line while a storage vessel affected facility vented to the 
closed vent system contains VOL or is being degassed.
    (9) After installing a closed vent system and control device to 
comply with Sec.  60.112c other than a flare or an enclosed combustion 
device electing to comply with Sec.  60.112c(d)(5), report:
    (i) For each instance when the CMS measured 3-hour rolling averages 
below the established operating limit:
    (A) The date and start time of the deviation;
    (B) The duration of the deviation in hours;
    (C) The lowest 3-hour rolling average operating parameter reading 
during the period of the deviation;
    (D) A unique identifier for the CMS;
    (E) The make, model number, and date of last calibration check of 
the CMS; and
    (F) The cause of the deviation and the corrective action taken.
    (ii) For all instances when the CMS was inoperative:
    (A) The date and start time of the deviation;
    (B) The duration of the deviation in hours;
    (C) A unique identifier for the CMS;
    (D) The make, model number, and date of last calibration check of 
the CMS; and
    (E) The cause of the deviation and the corrective action taken.
    (10) After installing a closed vent system and a flare to comply 
with Sec.  60.112c or an enclosed combustion device electing to comply 
with Sec.  60.112c(d)(5), report:
    (i) The date and start and end times for each of the following 
instances:
    (A) Each 15-minute block during which there was at least 1 minute 
when storage vessel vapors were routed to the flare and no pilot flame 
or flare flame was present.
    (B) Each period of 2 consecutive hours during which visible 
emissions exceeded a total of 5 minutes. Additionally, report the 
number of minutes for which visible emissions were observed during the 
observation or an estimate of the cumulative number of minutes in the 
2-hour period for which

[[Page 83335]]

emissions were visible based on best information available to the owner 
or operator.
    (C) Each 15-minute period for which the applicable operating limits 
specified in 40 CFR 63.670(d) through (f) were not met. You must 
identify the specific operating limit that was not met and report the 
value of the net heating value operating parameter(s) during the 
deviation determined following the methods in 40 CFR 63.670(k) through 
(n) as applicable.
    (ii) The start date, start time, and duration in minutes for each 
period when storage vessel vapors were routed to the flare or enclosed 
combustion device and the applicable monitoring was not performed.
    (iii) For each instance reported under paragraphs (c)(10)(i) and 
(ii) of this section that involves CMS, report the following 
information:
    (A) A unique identifier for the CMS;
    (B) The make, model number, and date of last calibration check of 
the CMS; and
    (C) The cause of the deviation or downtime and the corrective 
action taken.
    (11) For pressure relief devices on a storage vessel or closed vent 
system subject to Sec.  60.112c(d)(1)(iii) or (d)(2)(iii), report each 
pressure release to the atmosphere, including pressure relief device 
identification name or number, the start date, start time, and duration 
(in minutes) of the pressure release; and an estimate of the mass 
quantity in pounds of VOL released.
    (12) For vacuum breaking devices on a storage vessel subject to 
Sec.  60.112c(d) and (d)(1)(iii), report the following information for 
each time the vacuum breaking device failed to close prior to the 
storage vessel reaching atmospheric pressure: identification name or 
number of vacuum breaking device; the start date, start time, and 
duration (in minutes) of the pressure release; and an estimate of the 
mass quantity in pounds of VOL released.
    (d) Timeframe for semiannual report submissions. (1) The first 
semiannual report will cover the period starting with the date the 
source first becomes an affected facility subject to this subpart and 
ending June 30 or December 31, whichever date is earlier. For example, 
if the source becomes an affected facility on April 15, the first 
semiannual report would cover the period from April 15 to June 30. The 
first semiannual report must be submitted on or before the last day of 
the month 2 months after the last date covered by the semiannual 
report. In this example, the first semiannual report would be due 
August 31.
    (2) Subsequent semiannual reports will cover subsequent 6 calendar 
month periods (January 1 through June 30 or July 1 through December 31, 
as applicable) with each report due on or before the last day of the 
month 2 months after the last date covered by the semiannual report 
(August 31 or February 28 or 29, as applicable).
    (3) For each affected facility that is subject to permitting 
regulations pursuant to 40 CFR parts 70 or 71, if the delegated 
authority has established dates for submitting semiannual reports 
pursuant to 40 CFR 70.6(a)(3)(iii)(A) or 71.6(a)(3)(iii)(A), you may 
submit the first and subsequent semiannual reports according to the 
dates the delegated authority has established instead of the dates in 
paragraphs (d)(1) and (2) of this section.
    (e) Reporting requirements for performance tests. Within 60 days 
after the date of completing each performance test, you must submit the 
results following the procedures specified in paragraph (f) of this 
section. Data collected using test methods that are supported by the 
U.S. Environmental Protection Agency (EPA) Electronic Reporting Tool 
(ERT) as listed on the EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at 
the time of the test must be submitted in a file format generated using 
the EPA's ERT. Alternatively, you may submit an electronic file 
consistent with the extensible markup language (XML) schema listed on 
the EPA's ERT website. Data collected using test methods that are not 
supported by the EPA's ERT as listed on the EPA's ERT website at the 
time of the test must be included as an attachment in the ERT or an 
alternate electronic file.
    (f) Requirements for electronically submitting reports. If you are 
required to submit notifications or reports following the procedures 
specified in this paragraph (f), you must submit notifications or 
reports to the EPA via CEDRI, which can be accessed through the EPA's 
Central Data Exchange (CDX) (https://cdx.epa.gov/). The EPA will make 
all the information submitted through CEDRI available to the public 
without further notice to you. Do not use CEDRI to submit information 
you claim as confidential business information (CBI). Although we do 
not expect persons to assert a claim of CBI, if you wish to assert a 
CBI claim for some of the information in the report, you must submit a 
complete file in the format specified in this subpart, including 
information claimed to be CBI, to the EPA following the procedures in 
paragraphs (f)(1) and (2) of this section. Clearly mark the part or all 
of the information that you claim to be CBI. Information not marked as 
CBI may be authorized for public release without prior notice. 
Information marked as CBI will not be disclosed except in accordance 
with procedures set forth in 40 CFR part 2. All CBI claims must be 
asserted at the time of submission. Anything submitted using CEDRI 
cannot later be claimed CBI. Furthermore, under CAA section 114(c), 
emissions data are not entitled to confidential treatment, and the EPA 
is required to make emissions data available to the public. Thus, 
emissions data will not be protected as CBI and will be made publicly 
available. You must submit the same file submitted to the CBI office 
with the CBI omitted to the EPA via the EPA's CDX as described earlier 
in this paragraph (f).
    (1) The preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol, or 
other online file sharing services. Electronic submissions must be 
transmitted directly to the OAQPS CBI Office at the email address 
<a href="/cdn-cgi/l/email-protection#0a656b7b7a796968634a6f7a6b246d657c"><span class="__cf_email__" data-cfemail="2c434d5d5c5f4f4e456c495c4d024b435a">[email protected]</span></a>, and as described above, should include clear CBI 
markings. ERT files should be flagged to the attention of the 
Measurement Policy Group Leader and all other files should be flagged 
to the attention of the NSPS Kc Rule Lead. If assistance is needed with 
submitting large electronic files that exceed the file size limit for 
email attachments, and if you do not have your own file sharing 
service, please email <a href="/cdn-cgi/l/email-protection#cfa0aebebfbcacada68faabfaee1a8a0b9"><span class="__cf_email__" data-cfemail="c8a7a9b9b8bbabaaa188adb8a9e6afa7be">[email protected]</span></a> to request a file transfer link.
    (2) If you cannot transmit the file electronically, you may send 
CBI information through the postal service to the following address: 
U.S. EPA, Attn: OAQPS Document Control Officer, Mail Drop: C404-02, 109 
T.W. Alexander Drive, P.O. Box 12055, RTP, NC 27711. ERT files should 
be sent to the secondary attention of the Measurement Policy Group 
Leader and all other files should be sent to the secondary attention of 
the NSPS Kc Rule Lead. The mailed CBI material should be double wrapped 
and clearly marked. Any CBI markings should not show through the outer 
envelope.
    (g) Claims of EPA system outage. If you are required to 
electronically submit a report through CEDRI in the EPA's CDX, you may 
assert a claim of EPA system outage for failure to timely comply with 
that reporting requirement. To assert a claim of EPA system outage, you 
must meet the requirements outlined in paragraphs (g)(1) through (7) of 
this section.

[[Page 83336]]

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


Sec.  60.117c  Delegation of authority.

    (a) In delegating implementation and enforcement authority of this 
subpart to a State, local, or Tribal agency under section 111(c) of the 
Act, the authorities contained in paragraph (b) of this section shall 
be retained by the Administrator of U.S. EPA and cannot be transferred 
to the State, local, or Tribal agency.
    (b) Authorities which will not be delegated to State, local, or 
Tribal agencies: Sec. Sec.  60.113c(d)(1)(iv) and 60.114c and approval 
of an alternative to any electronic reporting to the EPA required by 
this subpart.

[FR Doc. 2024-22823 Filed 10-11-24; 8:45 am]
BILLING CODE 6560-50-P


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