
[Federal Register Volume 88, Number 191 (Wednesday, October 4, 2023)]
[Proposed Rules]
[Pages 68535-68553]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-21976]



[[Page 68535]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2023-0358; FRL-10655-01-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: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing 
amendments to the Standards of Performance for Volatile Organic Liquid 
Storage Vessels (Including Petroleum Liquid Storage Vessels) as the 
preliminary results of the review of the New Source Performance 
Standards (NSPS) required by the Clean Air Act. The EPA is proposing 
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. In the new 
NSPS subpart, the EPA is proposing to reduce the vapor pressure 
applicability thresholds In addition, the EPA is proposing to revise 
the volatile organic compound (VOC) standards to reflect the best 
system of emissions reductions (BSER) for affected storage vessels. We 
are also proposing additional monitoring and operating requirements to 
ensure continuous compliance with the standard. In addition, the EPA is 
proposing degassing emission controls; clarification of startup, 
shutdown, and malfunction requirements; requirements for electronic 
reporting; and other technical improvements. The EPA is also proposing 
to amend NSPS subpart Kb to apply to VOL storage vessels that commence 
construction, reconstruction or modification after July 23, 1984 and on 
or before October 4, 2023 and to add electronic reporting requirements.

DATES: 
    Comments. Comments must be received on or before November 20, 2023. 
Comments on the information collection provisions submitted to the 
Office of Management and Budget (OMB) under the Paperwork Reduction Act 
(PRA) are best assured of consideration by OMB if OMB receives a copy 
of your comments on or before November 3, 2023.
    Public Hearing. If anyone contacts us requesting a public hearing 
on or before October 10, 2023, we will hold a virtual hearing. Please 
refer to the SUPPLEMENTARY INFORMATION for information on requesting 
and registering for a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2023-0358, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov 
(our preferred method). Follow the online instructions for submitting 
comments.
     Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2023-0358 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2023-0358.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2023-0358, Mail Code 28221T, 1200 
Pennsylvania Avenue NW, Washington, DC 20460.
     Hand/Courier Delivery: EPA Docket Center, WJC West 
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. 
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m., Monday-
Friday (except Federal Holidays).
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the SUPPLEMENTARY 
INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact U.S. EPA, Attn: Michael Cantoni, Mail Drop: E143-01, 
109 T.W. Alexander Drive, P.O. Box 12055, RTP, NC 27711; telephone 
number: (919) 541-5593; and email address: [email protected].

SUPPLEMENTARY INFORMATION: 
    Participation in virtual public hearing. To request a virtual 
public hearing, contact the public hearing team at (888) 372-8699 or by 
email at [email protected]. If requested, the virtual hearing 
will be held on October 19, 2023. The hearing will convene at 11:00 
a.m. Eastern Time (ET) and will conclude at 3:00 p.m. ET. The EPA may 
close a session 15 minutes after the last pre-registered speaker has 
testified if there are no additional speakers. The EPA will announce 
further details at https://www.epa.gov/stationary-sources-air-pollution/volatile-organic-liquid-storage-vessels-including-petroleum.
    If a public hearing is requested, the EPA will begin pre-
registering speakers for the hearing no later than 1 business day after 
the publication of this document in the Federal Register. To register 
to speak at the virtual hearing, please use the online registration 
form available at https://www.epa.gov/stationary-sources-air-pollution/volatile-organic-liquid-storage-vessels-including-petroleum or contact 
the public hearing team at (888) 372-8699 or by email at 
[email protected]. The last day to pre-register to speak at the 
hearing will be October 16, 2023. Prior to the hearing, the EPA will 
post a general agenda that will list pre-registered speakers at: 
https://www.epa.gov/stationary-sources-air-pollution/volatile-organic-liquid-storage-vessels-including-petroleum.
    The EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing; however, please plan for the 
hearings to run either ahead of schedule or behind schedule.
    Each commenter will have 4 minutes to provide oral testimony. The 
EPA encourages commenters to submit a copy of their oral testimony as 
written comments to the rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations 
but will not respond to the presentations at that time. Written 
statements and supporting information submitted during the comment 
period will be considered with the same weight as oral testimony and 
supporting information presented at the public hearing.
    Please note that any updates made to any aspect of the hearing will 
be posted online at https://www.epa.gov/stationary-sources-air-pollution/volatile-organic-liquid-storage-vessels-including-petroleum. 
While the EPA expects the hearing to go forward as described in this 
section, please monitor our website or contact the public hearing team 
at (888) 372-8699 or by email at [email protected] to determine 
if there are any updates. The EPA does not intend to publish a document 
in the Federal Register announcing updates.
    If you require the services of a translator or a special 
accommodation such as audio description, please pre-register for the 
hearing with the public hearing team and describe your needs by October 
11, 2023. The EPA may not be able to arrange accommodations without 
advanced notice.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2023-0358. All

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documents in the docket are listed in the Regulations.gov index. 
Although listed in the index, some information is not publicly 
available, e.g., Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, is not placed on the internet 
and will be publicly available only in hard copy.
    Written Comments. Submit your comments, identified by Docket ID No. 
EPA-HQ-OAR-2023-0358, at https://www.regulations.gov (our preferred 
method), or the other methods identified in the ADDRESSES section. Once 
submitted, comments cannot be edited or removed from the docket. The 
EPA may publish any comment received to its public docket. Do not 
submit to EPA's docket at https://www.regulations.gov any information 
you consider to be Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. This type of 
information should be submitted as discussed in the Submitting CBI 
section of this document.
    Multimedia submissions (audio, video, etc.) must be accompanied by 
a written comment. The written comment is considered the official 
comment and should include discussion of all points you wish to make. 
The EPA will generally not consider comments or comment contents 
located outside of the primary submission (i.e., on the Web, cloud, or 
other file sharing system). Please visit https://www.epa.gov/dockets/commenting-epa-dockets for additional submission methods; the full EPA 
public comment policy; information about CBI or multimedia submissions; 
and general guidance on making effective comments.
    The https://www.regulations.gov website allows you to submit your 
comment anonymously, which means the EPA will not know your identity or 
contact information unless you provide it in the body of your comment. 
If you send an email comment directly to the EPA without going through 
https://www.regulations.gov, your email address will be automatically 
captured and included as part of the comment that is placed in the 
public docket and made available on the internet. If you submit an 
electronic comment, the EPA recommends that you include your name and 
other contact information in the body of your comment and with any 
digital storage media you submit. If the EPA cannot read your comment 
due to technical difficulties and cannot contact you for clarification, 
the EPA may not be able to consider your comment. Electronic files 
should not include special characters or any form of encryption and be 
free of any defects or viruses.
    Submitting CBI. Do not submit information containing CBI to the EPA 
through https://www.regulations.gov. Clearly mark the part or all of 
the information that you claim to be CBI. For CBI information on any 
digital storage media that you mail to the EPA, note the docket ID, 
mark the outside of the digital storage media as CBI, and identify 
electronically within the digital storage media the specific 
information that is claimed as CBI. In addition to one complete version 
of the comments that includes information claimed as CBI, you must 
submit a copy of the comments that does not contain the information 
claimed as CBI directly to the public docket through the procedures 
outlined in the Written Comments section of this document. If you 
submit any digital storage media that does not contain CBI, mark the 
outside of the digital storage media clearly that it does not contain 
CBI and note the docket ID. Information not marked as CBI will be 
included in the public docket and the EPA's electronic public docket 
without prior notice. Information marked as CBI will not be disclosed 
except in accordance with procedures set forth in 40 Code of Federal 
Regulations (CFR) part 2.
    Our preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol (FTP), 
or other online file sharing services (e.g., Dropbox, OneDrive, Google 
Drive). Electronic submissions must be transmitted directly to the 
OAQPS CBI Office at the email address [email protected], and as 
described above, should include clear CBI markings and note the docket 
ID. 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 [email protected] to 
request a file transfer link. If sending CBI information through the 
postal service, please send it 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, Attention Docket ID No. 
EPA-HQ-OAR-2023-0358. The mailed CBI material should be double wrapped 
and clearly marked. Any CBI markings should not show through the outer 
envelope.
    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:

API American Petroleum Institute
ASTM American Society for Testing and Materials
BSER best system of emission reduction
CAA Clean Air Act
CBI Confidential Business Information
CDX Central Data Exchange
CE cost effectiveness
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
ET Eastern Time
FR Federal Register
HAP hazardous air pollutant(s)
ICE incremental cost effectiveness
ICR information collection request
IFR internal floating roof
kPa kilopascals
LEL lower explosive limit
m3 cubic meters
NAICS North American Industry Classification System
NESHAP national emission standards for hazardous air pollutants
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PRA Paperwork Reduction Act
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 malfunctions
TAC total annualized cost
TCI total capital investment
tpy tons per year
UMRA Unfunded Mandates Reform Act
U.S.C. United States Code
VOC volatile organic compound(s)
VOL volatile organic liquid(s)

    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?
II. Background
    A. What is the statutory authority for this action?
    B. What is this source category and what are the current NSPS 
requirements?
    C. How does the EPA perform the NSPS review?
    D. What data and information were used to support this action?
III. What actions are we proposing?
    A. What vapor pressure applicability thresholds are we proposing 
and why?

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    B. What other changes to applicability are we proposing and why?
    C. What are the proposed BSER and compliance alternatives for 
newly constructed, modified, and reconstructed storage vessels?
    D. What is the BSER and standard of performance for new and 
reconstructed storage vessels with maximum true vapor pressures less 
than 11.1 psia?
    E. What compliance alternatives are available for new and 
reconstructed storage vessels with maximum true vapor pressures less 
than 11.1 psia?
    F. What is the BSER and standard of performance for new, 
modified, and reconstructed storage vessels with maximum true vapor 
pressures equal to or greater than 11.1 psia?
    G. What actions constitute a modification for storage vessels 
and why?
    H. What are the BSER and standards of performance for modified 
storage vessels with maximum true vapor pressures less than 11.1 
psia?
    I. What control requirements are we proposing for IFR and EFR 
storage vessels emptying and degassing and why?
    J. What requirements are we proposing for storage vessel 
testing, monitoring, and inspections and why?
    K. Proposal of NSPS subpart Kc without startup, shutdown, and 
malfunction exemptions
    L. Electronic Reporting
    M. Other Proposed Actions
    N. Compliance Dates
IV. 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?
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive 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

I. General Information

A. Does this action apply to me?

    The source category that is the subject of this proposal is 
composed of VOL storage vessels regulated under Clean Air Act (CAA) 
section 111, New Source Performance Standards. The 2022 North American 
Industry Classification System (NAICS) codes for this source category 
are 325, 324, and 422710. The NAICS codes serve as a guide for readers 
outlining the entities that this proposed action is likely to affect. 
The proposed standards, once promulgated, will be directly applicable 
to affected facilities that begin construction, reconstruction, or 
modification after the date of publication of the proposed standards in 
the Federal Register. Federal, State, local and Tribal government 
entities that own and/or operate storage vessels would be affected by 
this action.

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

    In addition to being available in the docket, an electronic copy of 
this action is available on the internet 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 
proposal and key technical documents at this same website.
    A memorandum showing the edits that would be necessary to 
incorporate the changes to 40 CFR part 60, subparts Kb and Kc proposed 
in this action is available in the docket (Docket ID No. EPA-HQ-OAR-
2023-0358). Following signature by the EPA Administrator, the EPA also 
will post a copy of this document to https://www.epa.gov/stationary-sources-air-pollution/volatile-organic-liquid-storage-vessels-including-petroleum.

II. Background

A. What is the statutory authority for this action?

    The EPA's authority for this proposed 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 non-air 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 (BSER) 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 
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

[[Page 68538]]

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 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. 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. What is this source category and what are the current NSPS 
requirements?

    The EPA promulgated NSPS subpart K, specific to storage vessels for 
petroleum liquids, in 1974 (39 FR 9317, March 8, 1974). These standards 
were amended several times before 1980, when EPA proposed to establish 
revised NSPS for storage vessels for petroleum liquids 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 volatile organic liquid 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 true vapor 
pressure over 15.0 kilopascals (kPa) (~2.18 psia), and from storage 
vessels with a capacity of 151 m\3\ (~40,000 gallons) or more that 
store organic liquids with a true vapor pressure over 3.5 kPa (~0.51 
psia). VOC emissions controls are required on storage vessels with a 
capacity of 75 cubic meters (m\3\) (~20,000 gallons) or more that store 
VOLs with a true vapor pressure over 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 a true vapor pressure over 5.2 kPa 
(~0.75 psia). NSPS subpart Kb emission controls include the use of 
either 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)). \2\ 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 \3\ 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 59329), 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\ 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 EFR.
    NSPS subpart Kb also requires numerous deck fittings \4\ 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.\5\
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    \4\ 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 ports, 
rim vents, deck drains, deck legs, vacuum breakers, and guidepoles. 
IFR storage vessels may also have deck seams, fixed-roof support 
columns, ladders, and/or stub drains.
    \5\ 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-and-quantification/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. 
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.
    We estimate that there were approximately 9,100 storage vessels 
subject to NSPS subpart Kb in 2022, with an estimated 240 storage 
vessels becoming new affected facilities under the rule each year. 
Under the current NSPS subpart Kb requirements, it is generally 
difficult to become a modified storage vessel.

[[Page 68539]]

C. 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, 
those standards must reflect the degree of emission limitation 
achievable through the application of the BSER considering the cost of 
achieving such reduction and any non-air 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:
     Expected growth for the source category, including how 
many new facilities, reconstructions, and modifications may trigger 
NSPS in the future.
     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.
     Available information from the implementation and 
enforcement of current requirements indicating that emission 
limitations and percent reductions beyond those required by the current 
standards are achieved in practice.
     Costs (including capital and annual costs) associated with 
implementation of the available pollution control measures.
     The amount of emission reductions achievable through 
application of such pollution control measures.
     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 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 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 new source performance standards reflect the best system of 
emission reduction 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.
    See section II.D of this preamble for information on the specific 
data sources that were reviewed as part of this action.

D. What data and information were used to support this action?

    We reviewed recent federal, State, and local rulemakings associated 
with VOL storage vessels. We also reviewed vendor websites and 
contacted selected floating roof suppliers to collect information to 
support our review of the existing requirements for organic liquid 
storage vessels and our BSER assessments. We met with industry 
representatives that own and operate VOL storage vessels to discuss 
their experience with various control equipment.
    We used the equations in Chapter 7 of AP-42: Compilation of Air 
Emission Factors to estimate emissions from different VOL storage 
vessels based on size, contents, and control configuration (e.g., type 
of floating roof with different seal and fitting controls). We 
estimated emission reductions by comparing the controlled emissions 
with emissions from an uncontrolled fixed roof storage vessel.
    Our cost estimates were based largely on vendor costs developed 
from previous rulemakings. For some control methods, we had limited 
recent data from vendors or State and local rulemakings. All costs were 
escalated to 2022 dollars using the Chemical Engineering Plant Cost 
Index for capital expenditures and Bureau of Labor Statistics data for 
labor rates.

III. What actions are we proposing?

    The EPA is proposing revisions to the NSPS for VOL storage vessels 
pursuant to the EPA's review of NSPS subpart Kb. The EPA is proposing 
to codify the NSPS revisions proposed in this action in a new subpart 
NSPS subpart Kc. The proposed NSPS subpart Kc would be applicable to 
sources that commence construction, reconstruction, or modification 
after October 4, 2023.
    This section outlines the proposed actions for NSPS subpart Kc. The 
EPA is proposing new vapor pressure applicability thresholds for 
controls under NSPS subpart Kc. The EPA is also proposing new standards 
for VOL storage vessels subject to control requirements. Under NSPS 
subpart Kc we are proposing that the standard of performance reflecting 
the application of BSER for VOL storage vessels subject to control 
requirements and used to store liquids with maximum true vapor 
pressures below 11.1 psia (76.6 kPa) is an IFR. The updated standards 
are projected to increase the average control efficiency of IFR storage 
vessels to 98 percent. As an alternative compliance to the proposed IFR 
design standard, we are proposing to permit either the use of an EFR or 
the use of a closed vent system and a control device that meet an 
equivalent standard of control. For controlled storage vessels that 
store liquids with a maximum true vapor pressure equal to or greater 
than 11.1 psia (76.6 kPa), we are proposing to find that the BSER is a 
closed vent system and a control device. We are proposing that the 
standard of performance reflecting the emission limitation achievable 
is a 98 percent reduction in VOC emissions (increased from 95 percent 
in the NSPS subpart Kb). EPA is also including modification 
requirements under NSPS subpart Kc and discusses the relevant criteria 
for meeting modifications in this section. This section also details 
the proposed testing, monitoring and inspection requirements, degassing 
provisions,

[[Page 68540]]

provisions for SSM, and electronic reporting requirements. As described 
in this section, the revisions proposed in this action were determined 
to be cost-effective and to reflect the application of the best system 
of emission reduction (BSER) for VOL storage vessels.

A. What vapor pressure applicability thresholds are we proposing and 
why?

    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.
    In NSPS subpart Kb, the vapor pressure applicability thresholds for 
defining affected facilities were slightly lower than those used for 
affected facilities for which controls were required. The EPA included 
the two separate applicability requirements sets in NSPS subpart Kb, 
one to identify storage vessels near the control applicability 
thresholds and another to establish limited monitoring procedures for 
vessels with variable components and vapor pressures. We are proposing 
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 volatile 
organic liquid without exclusion for storage vessels under a set vapor 
pressure. This proposed change simplifies the applicability under NSPS 
subpart Kc and establishes a baseline for monitoring and recordkeeping 
in accordance with good air pollution control practices for storage 
vessels that do not meet the vapor pressure emission control threshold.
    In our review of NSPS subpart Kb, in assessing the vapor 
applicability thresholds that require emission controls, we estimated 
the cost of including an IFR as part of a new fixed roof storage vessel 
installation for a variety of surrogate organic liquids covering a wide 
range of vapor pressures for both 20,000 gallon and 40,000 gallon 
capacity storage vessels. We used the AP-42 equations for liquid 
storage tanks to estimate emissions for fixed roof storage vessels and 
IFR storage vessels. Costs were estimated based on various vendor 
quotes, escalated to 2022$. For more detail regarding the analyses 
conducted, see memorandum Control Options for Storage Vessels included 
in Docket ID No. EPA-HQ-OAR-2023-0358.
    For storage vessels of 20,000 gallon capacity or more but less than 
40,000 gallon capacity, we evaluated the cost and cost effectiveness of 
different vapor pressure applicability thresholds, including:
     4.0 psia based on NSPS subpart Kb value (27.6 kPa)
     1.9 psia based on thresholds used in several NESHAP 
including 40 CFR part 63, subparts G and CC.
     1.5 psia based on thresholds in South Coast Air Quality 
Management District (SCAQMD) Rule 463.
     1.0 psia to evaluate an option beyond 1.5 psia.
    We conducted this analysis using a model storage vessel of 20,000 
gallon capacity. We assessed costs for two different levels of IFR: one 
meeting the basic requirements of NSPS subpart Kb and one with upgraded 
seal requirements (requiring a mechanical shoe seal or liquid-mounted 
primary seal with a rim-mounted secondary seal). Table 1 summarizes the 
results of our analysis for these small storage vessels.

  Table 1--Summary of Threshold Analysis for Storage Vessels With a Capacity Between 20,000 and 40,000 Gallons
----------------------------------------------------------------------------------------------------------------
                                                                      TAC \2\
                                   VOC emissions                      without      TAC \2\ with
            Threshold                reduction      TCI \1\ ($)       product         product      CE \3\ ($/ton
                                       (tpy)                       recovery ($/    recovery ($/        VOC)
                                                                        yr)             yr)
----------------------------------------------------------------------------------------------------------------
                             Costs for Meeting NSPS Subpart Kb Requirements for IFR
----------------------------------------------------------------------------------------------------------------
4.0 psia........................            2.04         $48,877          $6,035          $4,257          $2,100
----------------------------------------------------------------------------------------------------------------
1.9 psia........................            0.97          48,877           6,035           5,190           5,300
1.5 psia........................            0.77          48,877           6,035           5,368           7,000
1.0 psia........................            0.51          48,877           6,035           5,590          10,900
----------------------------------------------------------------------------------------------------------------
                           Costs for IFR with Upgraded Seal Requirements (`Option 1')
----------------------------------------------------------------------------------------------------------------
4.0 psia........................            2.29          55,008           6,793           4,802           2,100
1.9 psia........................            1.09          55,008           6,793           5,847           5,000
1.5 psia........................            0.86          55,008           6,793           6,046           7,000
1.0 psia........................            0.57          55,008           6,793           6,295          11,000
----------------------------------------------------------------------------------------------------------------
\1\ Total Capital Investment (TCI).
\2\ Total annualized costs (TAC) considering annualized cost of capital.
\3\ Cost effectiveness.

    A similar analysis was conducted for storage vessels with a design 
capacity of 40,000 gallons or more. For this analysis, we used a model 
storage vessel with a 60,000 gallon capacity, which we consider 
representative of storage vessels at the smaller end of the range of 
storage vessels with a capacity of 40,000 gallons or more. We evaluated 
the cost and cost effectiveness of different vapor pressure 
applicability thresholds, including:
     0.75 psia based on NSPS subpart Kb value (5.2 kPa).
     0.50 based on thresholds in SCAQMD Rule 463.
     0.35 psia to evaluate an option beyond 0.5 psia.
    Table 2 summarizes the results of our analysis for storage vessels 
with a capacity of 40,000 gallons or more.

[[Page 68541]]



      Table 2--Summary of Threshold Analysis For Storage Vessels With a Capacity of 40,000 Gallons or More
----------------------------------------------------------------------------------------------------------------
                                                                      TAC \2\
                                   VOC emissions                      without      TAC \2\ with
            Threshold                reduction      TCI \1\ ($)       product         product      CE \3\ ($/ton
                                       (tpy)                       recovery ($/    recovery ($/        VOC)
                                                                        yr)             yr)
----------------------------------------------------------------------------------------------------------------
                             Costs for Meeting NSPS Subpart Kb Requirements for IFR
----------------------------------------------------------------------------------------------------------------
0.75 psia.......................            1.36         $54,979          $6,789          $5,609          $4,100
----------------------------------------------------------------------------------------------------------------
0.50 psia.......................            0.90          54,979           6,789           6,002           6,600
0.35 psia.......................            0.63          54,979           6,789           6,238           9,900
----------------------------------------------------------------------------------------------------------------
                           Costs for IFR with Upgraded Seal Requirements (`Option 1')
----------------------------------------------------------------------------------------------------------------
0.75 psia.......................            1.42          62,914           7,769           6,532           4,600
0.50 psia.......................            0.95          62,914           7,769           6,944           7,300
0.35 psia.......................            0.66          62,914           7,769           7,192          10,800
----------------------------------------------------------------------------------------------------------------
\1\ Total Capital Investment (TCI).
\2\ Total annualized costs (TAC) considering annualized cost of capital.
\3\ Cost effectiveness.

    Based on this analysis, we are proposing for NSPS subpart Kc to 
revise the vapor applicability thresholds that require emission 
controls. We are proposing to revise the maximum true vapor pressure 
threshold for small 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. These thresholds yield emission reductions at a cost of 
approximately $6,000 and $7,000 per ton of VOC reduced respectively, 
which is within the range of what the EPA has considered cost-effective 
for the control of VOC emissions in other recent NSPS rulemakings. See, 
e.g., 88 FR 29982 (May 9, 2023) (finding a value of $6,800/ton of VOC 
emissions reductions cost-effective for automobile and light duty truck 
surface coating operations (NSPS subpart MMa)). The cost effectiveness 
for VOLs with vapor pressures less than the proposed maximum true vapor 
pressure cutoffs are approximately $10,000 and $11,000 per ton of VOC 
reduced. This is not cost-effective because it is significantly higher 
than what the EPA has historically found to be cost-effective for VOC 
regulations. The EPA solicits comment on the proposed vapor pressure 
applicability described in this section.

B. What other changes to applicability are we proposing and why?

    NSPS subpart Kb includes several provisions that exempt specific 
groups of VOL storage vessels from applicability under the standard. 
These exemptions are outlined in 40 CFR 60.110b (d) and include 
specific exemptions for storage vessels that operate at coke oven by-
product plants, bulk gasoline plants, and gasoline service stations. 
The exemptions include pressure vessels operating in excess of 204.9 
kPA, vessels attached to mobile vehicles, and vessels that store 
beverage alcohol. These exemptions are being carried over into the 
proposal for NSPS Kc as the justifications for their exemption remains 
unchanged from the original NSPS subpart Kb promulgation.
    The EPA is also proposing to carry over the exemption requirements 
in 40 CFR 60.110b(d)(4), which covers storage vessels with capacities 
less than or equal to 1,589.874 m\3\ (~420,000 gallons) used for 
petroleum or condensate stored, processed, or treated prior to custody 
transfer. The EPA previously explained the applicability of this 
exemption in the preamble to NSPS subpart Ka (45 FR 23377) stating, 
``this exemption applies to storage between the time that the petroleum 
liquid is removed from the ground and the time the custody of the 
petroleum liquid is transferred from the well or producing operations 
to the transportation operations. If it is determined in the future 
that VOC emissions from new production field vessels smaller than 
1,589,873 liters (420,000 gallons) are significant, separate standards 
of performance will be developed.'' Since promulgation of NSPS subpart 
Ka, the EPA promulgated subparts OOOO and OOOOa for the oil and natural 
gas sector, which include standards of performance for these types of 
storage vessels. The EPA has also proposed revised standards for these 
sources in its latest review, as part of the proposed NSPS subpart 
OOOOb and the emission guideline for existing sources at proposed 
subpart OOOOc. See 87 FR 74702. As such, the EPA proposes to carry the 
language of this exemption into NSPS subpart Kc.
    NSPS subpart Kb also includes an exemption for vessels subject to 
the NESHAP for solvent extraction for vegetable oil production outlined 
in 40 CFR 63 subpart GGGG. The EPA determined as part of its review, 
that the standards proposed in NSPS subpart Kc improve upon the 
existing NESHAP subpart GGGG standards. As such, the EPA proposes that 
vessels subject to NESHAP subpart GGGG, would not be exempted from NSPS 
subpart Kc applicability.
    The EPA solicits comment on these proposed exemptions and changes 
to the applicability provisions.

C. What are the proposed BSER and compliance alternatives for newly 
constructed, modified, and reconstructed storage vessels?

    The EPA is proposing standards of performance that reflect the BSER 
as well as alternative compliance standards for controlled storage 
vessels under NSPS subpart Kc. The proposed BSER analyses and proposed 
standards for NSPS subpart Kc are dependent on the maximum true vapor 
pressure of a stored VOL and follow the precedent established in NSPS 
subpart Kb. For storage vessels storing VOL with maximum true vapor 
pressures less than 11.1 psia, the EPA discusses the BSER analysis and 
proposes standards of performance for newly constructed and 
reconstructed IFRs in section III.D. The EPA also is proposing two 
alternative compliance options for storage vessels with maximum true 
vapor pressures less than 11.1 psia. These alternative compliance 
options are EFRs and closed vent system and control. Details regarding 
alternative compliance standards for newly constructed and 
reconstructed storage vessels are discussed in section III.E.

[[Page 68542]]

    For storage vessels with maximum true vapor pressures greater than 
or equal to 11.1 psia, the EPA is proposing to determine that the BSER 
is closed vent system and control, and the standard of performance 
reflecting the BSER is a 98 percent reduction in VOC emissions. The 
BSER analysis and standard of performance for storage vessels with VOL 
maximum true vapor pressures greater than or equal to 11.1 psia are 
discussed in section III.F. Additionally, we are proposing requirements 
that are applicable to storage vessels that are controlled using a 
closed vent system and a control device to meet either proposed 
standard, and those proposed requirements are also discussed in section 
III.F.
    In section III.G the EPA proposes what constitutes a modification 
for purposes of NSPS subpart Kc. Discussion regarding the BSER 
analysis, standards of performance for modified storage vessels and 
compliance alternatives are discussed in sections III.F and III.H.

D. What is the BSER and standard of performance for new and 
reconstructed storage vessels with maximum true vapor pressures less 
than 11.1 psia?

    In our review of NSPS subpart Kb for storage vessels storing VOL 
with maximum true vapor pressures less than 11.1 psia, we focused on 
control options for IFR storage vessels because IFR storage vessels are 
more effective at controlling emissions and are technologically 
achievable. Therefore, IFR storage vessel control options were 
evaluated to determine BSER for VOL vapor pressures less than 11.1 
psia. Because floating roof tanks are unsuitable for controlling VOL 
with vapor pressures greater than or equal 11.1 psia, the EPA conducted 
a separate analysis to determine the BSER and standard of performance 
for those storage vessels.
    The control options we evaluated for IFR storage vessels included:
     Baseline. NSPS subpart Kb control requirements (with NSPS 
subpart Kc proposed lower vapor pressure thresholds detailed in section 
III.A)
     Option IFR-1. NSPS subpart Kb but primary seal must either 
be liquid-mounted or mechanical shoe seal and must have a rim-mounted 
secondary seal.
     Option IFR-2. Option 1 requirements + require fixed roof 
legs or cable suspended roof (cannot have adjustable roof legs that 
penetrate through the floating roof).
     Option IFR-3. Option 2 requirements + require welded seems 
and best guidepole fittings.
    All three of the listed options above also include provisions for 
requiring gauge-hatches/sample ports to be gasketed. We determined that 
all of these IFR control options are in use in the industry and thus 
adequately demonstrated.
    The cost effectiveness of these control options is dependent on the 
size and contents of the storage vessel. We estimated that 
approximately 240 new storage vessels become subject to the NSPS 
subpart Kb every year, such that 1,200 new storage vessels could become 
subject to NSPS subpart Kc over the next five years if no change in 
thresholds is adopted. We projected that with lower vapor pressure 
thresholds, approximately 20 percent more storage vessels could become 
subject to the NSPS subpart Kc standards each year. We assigned the 
estimated 1,440 new storage vessels across a range of storage vessel 
sizes and vapor pressures for the stored liquids to develop national 
impact estimates for each IFR control option. For more information on 
the nationwide cost analysis of IFR control options for new storage 
vessels, see memorandum Control Options for Storage Vessels in Docket 
ID No. EPA-HQ-OAR-2023-0358.
    The national impacts projected for each IFR control option are 
presented in Table 3 of this preamble.

                         Table 3--Summary of National Impacts for Control Options for New and Reconstructed IFR Storage Vessels
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                              TAC \3\
                                           VOC emissions                      without      TAC \3\ with   Overall CE \1\   CE \4\ to Kb
             Control option                reduction \1\      TCI \2\         product         product       \4\ ($/ton     baseline ($/   ICE \5\ ($/ton
                                               (tpy)        (million $)      recovery        recovery          VOC)          ton VOC)          VOC)
                                                                          (million $/yr)  (million $/yr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline--Kb............................          41,886            $127           $15.7         ($20.8)          ($496)  ..............  ..............
Option IFR-1............................          42,420             145            17.9          (19.1)           (449)           3,180           3,180
Option IFR-2............................          42,684             173            21.3          (15.8)           (370)           6,250          12,272
Option IFR-3............................          42,961             199            24.6          (12.8)           (297)           7,470          10,966
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Relative to uncontrolled fixed roof storage vessel.
\2\ Total Capital Investment (TCI).
\3\ Total annualized costs (TAC) considering annualized cost of capital.
\4\ Cost effectiveness.
\5\ Incremental cost effectiveness (compared to previous option).

    Based on this analysis, we are proposing to determine that for new 
and reconstructed storage vessels with vapor pressures less than 11.1 
psia, BSER is Option IFR-1. Specifically, we are proposing to require 
that the primary seal must either be liquid-mounted or a mechanical 
shoe seal and must have a rim-mounted secondary seal. While Table 3 
displays numerous options that have favorable cost effectiveness 
values, incremental cost effectiveness was the determining factor in 
selecting the appropriate IFR control option. The EPA estimated that 
the incremental cost effectiveness of Option IFR-1 is projected to 
yield emission reductions at a cost of approximately $3,200 per ton of 
VOC reduced on average, which we determined is cost- effective and is 
well within the range of what the EPA has considered cost-effective for 
the control of VOC emissions. The other control options we evaluated 
for IFR storage vessels had incremental cost effectiveness of $11,000 
or more per ton of VOC reduced, which is well above what we have 
determined to be cost-effective for the control of VOC emissions. IFRs 
are the most common emission control method for VOL storage vessels and 
thus are adequately demonstrated. Further, IFRs do not require power or 
addition of add-on controls; therefore, there are minimal non-air 
quality health and environmental impacts and energy requirements.
    IFRs with a liquid-mounted or mechanical shoe primary seal and rim-
mounted secondary seal (Option IFR-1) were selected as the most 
appropriate option for new and reconstructed storage vessels under the 
BSER determination. The EPA therefore

[[Page 68543]]

proposes an equipment standard pursuant to CAA section 111(h)(5) that 
would require that new storage vessels be constructed as IFR, that the 
primary seal must either be liquid-mounted or mechanical shoe seal and 
must have a rim-mounted secondary seal, that gauge-hatches/sample ports 
to be gasketed, and that the guidepole configurations incorporate the 
provisions outlined in the 2000 EPA Storage Tank Emissions Reduction 
Partnership Program (STERPP).
    The EPA solicits comment on the proposal to determine that the BSER 
for storage vessels storing VOL with maximum true vapor pressures less 
than 11.1 psia is Option IFR-1, or whether one of the alternative 
options would be justified. The EPA also solicits comment on the 
proposed equipment standard.

E. What compliance alternatives are available for new and reconstructed 
storage vessels with maximum true vapor pressures less than 11.1 psia?

    As discussed in section III.D of this preamble, we are proposing to 
determine that, for new and reconstructed storage vessels with a 
maximum true vapor pressure less than 11.1 psia, the BSER and equipment 
standard is IFR with enhanced rim seal requirements: specifically, the 
primary seal must either be liquid-mounted or mechanical shoe seal and 
must have a rim-mounted secondary seal. We are also proposing to revise 
the NSPS requirements for EFR storage vessels as an alternative 
compliance option to equipment standard for newly constructed and 
reconstructed storage vessels. The average control efficiency for the 
proposed Option IFR-1 was determined to be 98 percent. In reviewing the 
NSPS, we found that certain EFR storage vessels could achieve the same 
level of control as the proposed control option for IFR storage vessels 
(Option IFR-1). As such, we are proposing to permit the use of EFR 
storage vessels that we determined achieve equivalent performance as an 
IFR storage vessel across a range of different capacities. Based on AP-
42 emission calculation methods, we found that an EFR storage vessel 
that has primary and secondary seals as specified in Option IFR-1, 
welded seams (typical construction for EFR), and that use an unslotted 
guidepole with gasketed sliding cover and pole wiper have emissions 
comparable to an IFR storage vessel under Option IFR-1. If a slotted 
guidepole is used, a liquid mounted primary seal must be used and the 
slotted guidepole must have a gasketed sliding cover, pole sleeve and 
pole wiper (with or without float). We recognize that other control 
combinations for the EFR storage vessel may achieve comparable 
emissions to an Option IFR-1 storage vessel depending on the size and 
content of the storage vessel, and the typical meteorological 
conditions. Although we are not attempting to identify every such 
combination in proposing to codify this compliance alternative, CAA 
section 111(h)(5) permits facilities to request an alternative means of 
emission limitation to assess equivalency of EFR controls to IFR 
controls under site-specific conditions.
    We are also proposing to permit storage vessels with a maximum true 
vapor pressure less than 11.1 psia to use closed vent system and 
control devices as an alternative compliance to the equipment standard, 
so long as the storage vessel achieves a 98 percent reduction in VOC 
emissions to be equivalent to the proposed IFR standard. Such storage 
vessels would be required to meet the proposed requirements for closed 
vent systems and control devices described in section III.F.
    The EPA solicits comment on these proposed compliance alternatives 
for storage vessels with a maximum true vapor pressure less than 11.1 
psia.

F. What is the BSER and standard of performance for new, modified, and 
reconstructed storage vessels with maximum true vapor pressures equal 
to or greater than 11.1 psia?

    As noted previously, the EPA is proposing that for newly 
constructed and reconstructed VOL storage vessels with a maximum true 
vapor pressure less than 11.1 psia, the BSER is IFR with enhanced rim 
seal requirements. Because floating roof tanks are unsuitable for 
controlling VOL with vapor pressures greater than or equal 11.1 psia, 
the EPA conducted a separate analysis to determine the BSER and 
standard of performance for those storage vessels that are new, 
modified, or reconstructed. In NSPS subpart Kb, closed vent systems and 
control devices are the BSER for storage vessels for organic liquids 
with maximum true vapor pressures of 11.1 psia or greater and have 
served as an alternative compliance option for storage vessels with 
lower vapor pressures. Therefore, in reviewing NSPS subpart Kb, the EPA 
also reviewed the control requirements associated with storage vessels 
that use closed vent systems and control devices. We assessed the cost 
and cost effectiveness of a closed vent system and control device for a 
range of storage vessels used to store liquids with high vapor 
pressures. We are proposing to continue to find the BSER to be closed 
vent systems and control devices for new, modified, or reconstructed 
storage vessels for organic liquids with maximum true vapor pressures 
of 11.1 psia or greater, and to set the standard of performance to 
require that these storage vessels must achieve a 98 percent reduction 
in VOC emissions.
    For storage vessels used to store organic liquids with maximum true 
vapor pressures of 11.1 psia or greater, we estimated the cost of a 
flare dedicated to a single storage vessel. We estimated the costs 
separately for flares meeting the requirements in 40 CFR 60.18 (95 
percent reduction) or using the flare requirements in 40 CFR 63.670 (98 
percent reduction). We used two times the maximum filling rate to size 
the flares, we determined the time period needed at the maximum filling 
rate to achieve the modeled working losses, and we determined the 
average flow rate needed for the remaining time period to correspond to 
the modeled standing losses. Because of the high vapor pressure of the 
liquid contents, flares meeting the requirements in 40 CFR 63.670 are 
expected to be able to use the methods in 40 CFR 63.670(j)(6) to 
determine minimum net heating value of the gas stream. Depending on the 
assist-type of the flare, supplemental gas may be needed during periods 
of low flow, which is the vast majority of the time. We expect 
facilities would use a pressure valve in the closed vent system to 
prevent low flows and prevent back flow from the flare to the storage 
vessel when emptying the storage vessel. These pressure valves could be 
set to ensure gas flow to the flare is always sufficient to prevent 
over-assisting, but we assumed flares with low flows would use 
supplemental natural gas. For smaller storage vessels (20,000 to 60,000 
gallons capacity), there were added costs associated with meeting the 
combustion zone operating limits in 40 CFR 63.670. For the larger 
storage vessels, routine flows from the storage vessels were sufficient 
to meet the combustion zone operating limits in 40 CFR 63.670. We 
estimate there would be 25 new storage vessels used for storing high 
vapor pressure liquids for which closed vent system and control device 
would be required, primarily in the 40,000 to 60,000 gallon capacity 
range. For more details regarding the nationwide of costs for closed 
vent systems and control devices, see memorandum Control Options for 
Storage Vessels in Docket ID No. EPA-HQ-OAR-2023-0358. The nationwide 
impacts projected for these two control options evaluated for purposes 
of NSPS

[[Page 68544]]

subpart Kc (95 percent and 98 percent control) are provided in Table 4 
of this preamble.

  Table 4--Summary of National Impacts for Control Options for Closed Vent Systems and Control Device for High
                                             Vapor Pressure Liquids
----------------------------------------------------------------------------------------------------------------
                                                                      TAC \3\
                                   VOC emissions                      without
         Control option            reduction \1\      TCI \2\         product      CE \4\ ($/ton  ICE \5\ ($/ton
                                       (tpy)        (million $)      recovery          VOC)            VOC)
                                                                  (million $/yr)
----------------------------------------------------------------------------------------------------------------
95 percent control..............             928           $2.69           $2.61          $2,820          $2,820
98 percent control..............             957            2.69            2.71           2,830           3,360
----------------------------------------------------------------------------------------------------------------
\1\ Relative to uncontrolled fixed roof storage vessel.
\2\ Total Capital Investment (TCI).
\3\ Total annualized costs (TAC) considering annualized cost of capital.
\4\ Cost effectiveness.
\5\ Incremental cost effectiveness.

    Based on our analysis, we are proposing that the BSER for storage 
vessels operating with maximum true vapor pressures equal to or greater 
than 11.1 psia is the use of a closed vent system and control device 
meeting a 98 percent control efficiency. The EPA considers the cost-
effectiveness of both control options to be within the range of what 
the EPA has considered cost- effective for the control of VOC 
emissions. While the incremental cost-effectiveness of 98 percent 
control is slightly higher than for 95 percent control, it is also well 
within the range of what the EPA has considered cost-effective. 
Although these control devices use power and result in additional 
combustion emissions, there is no significant difference between 95 and 
98 percent control levels in as regards to the non-air quality health 
and environmental impacts, or energy requirements. Accordingly, the EPA 
proposes to find the use of a closed vent system and control device 
meeting a 98 percent control efficiency is the BSER and proposes to set 
a standard of performance for new, reconstructed, and modified storage 
vessels operating with vapor pressures equal to or greater than 11.1 
psia as 98 percent control of VOC emissions.
    The EPA is also proposing to establish requirements for closed vent 
systems and control devices to ensure that storage vessels using them 
to comply with the proposed standards actually achieve 98 percent 
control efficiency. In order for the closed vent system and control 
device to meet 98 percent control efficiency, the storage vessel must 
not vent to the atmosphere. Conservation vents and pressure relief 
devices are often used to vent emissions from storage vessels when the 
pressure within the storage vessel approaches the maximum design 
pressure of the storage vessel. Many atmospheric storage vessels have 
pressure ratings of 1 or 2 psig and would therefore vent often if the 
vapor pressure of the stored liquid is above 2 psi. Consequently, to 
ensure direct venting from the storage vessel does not occur, we are 
proposing to require storage vessels have a design operating gauge 
pressure no less than 1 psi greater than the maximum vapor pressure of 
the liquid being stored and any back pressure anticipated when the 
storage vessel is filled at its maximum rate. While vapor pressures are 
commonly reported in terms of absolute pressure, a storage vessel 
containing a liquid with a vapor pressure of 4 psia would generally 
have a headspace pressure of 4 psi above atmospheric pressure, or 4 
psig. Storage vessel owners or operators would also have to evaluate 
the back pressure of the control system used and ensure that the closed 
vent system can handle the maximum filling rate of the storage vessel 
without increasing pressure in the storage vessel above this 5 psig 
value or else establish a higher design and operating pressure for the 
storage vessels. For example, if the back pressure of the closed vent 
system (or the pressure drop from the storage vessel to the control 
device) is 3 psi at the maximum filling rate, and the liquid stored has 
a maximum true vapor pressure of 4 psia, the minimum opening pressure 
of any pressure relief device on the storage vessel would have to be 8 
psig (3+4+additional 1). We are also proposing to require that any 
vacuum breaking device have a close pressure no less than 0.1 psig 
vacuum to prevent losses from the vacuum breaker vent.
    The EPA solicits comment on our proposed BSER determination and 
standard of performance for new, reconstructed, and modified storage 
vessels operating with vapor pressures equal to or greater than 11.1 
psia, as well as the proposed requirements for closed vent systems and 
control devices.

G. What actions constitute a modification for storage vessels and why?

    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.\6\ 40 CFR 
60.2. 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. In prior EPA actions making applicability 
determinations for purposes of NSPS Kb, the EPA has previously cited to 
this provision to assert that a change in the type of material stored 
in a storage vessel is not, by itself, a modification if the storage 
vessel is capable of accommodating the storage of the new materials.\7\ 
However, the EPA has revisited the previous interpretation as discussed 
in the following paragraphs and now proposes, for purposes of NSPS Kc, 
that a change in the liquid stored in the storage vessel to an organic 
liquid with a higher maximum true vapor pressure 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. Thus, the 
EPA proposes that a change in the liquid stored which results in 
increased

[[Page 68545]]

VOC emissions would be a modification under NSPS Kc. The EPA recognizes 
that the proposed approach to modifications for purposes of NSPS 
subpart Kc represents a change of the EPA's previous interpretation of 
the provision in 40 CFR 60.14(e)(4) that asserted that change in liquid 
alone did not trigger a modification. However, the EPA proposes to find 
that this change in interpretation for purposes of defining a 
modification for NSPS subpart Kc is appropriate, in particular, because 
as discussed below the changes in the organic liquid stored in a 
storage vessel do not constitute changes in ``fuel or raw material,'' 
as the primary function of this affected facility is the storage of 
materials, and the materials stored are neither raw material nor fuel 
inputs to a process at the facility itself. FCC v. Fox Television 
Stations, Inc., 556 U.S. 502, 515-16 (2009) (when the Agency 
acknowledges change in position, ``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'').
---------------------------------------------------------------------------

    \6\ See 42 U.S.C. 7411(a)(4).
    \7\ See, e.g., U.S. EPA Applicability Determination Index, 
Control Number: 0400015, (referencing 40 CFR 60.14(e)(4)-(5)).
---------------------------------------------------------------------------

    As noted earlier in this preamble, as the EPA has defined 
modification for purposes of CAA section 111, using a different fuel or 
raw material in the process that the facility was specifically designed 
for does not itself constitute a modification under the exemption 
identified in 40 CFR 60.14(e)(4). However, for storage vessels, the 
primary function of this affected facility is the storage of materials, 
and the materials stored are neither raw material nor fuel inputs to a 
process at the facility itself. Therefore, for purposes of NSPS Kc, the 
EPA now proposes to determine that the exemption outlined in 40 CFR 
60.14(e)(4) does not apply, because the organic liquid stored in the 
vessels subject to this part does not constitute fuels or raw 
materials. Accordingly, the EPA proposes to consider the change in 
materials stored in a storage vessel to be an operational change under 
CAA section 111(a)(4). Thus, where an owner or operator changes the 
operation of the tank to store materials with higher vapor pressures, 
this change results in an increased emission potential. The EPA 
proposes to find that this change is an operation meeting the 
definition of ``modification'' under CAA section 111(a)(4) and 40 CFR 
60.14(a). If the modified storage vessel meets the applicability 
criteria of NSPS subpart Kc, then it would be subject to the standards 
of performance and other requirements established in the final rule.
    The EPA has identified no other exemption in 40 CFR 60.14(e) which 
applies to a change in the organic liquid stored in a storage vessel. 
The EPA further proposes to determine that a change in the organic 
liquid stored at a storage vessel constitutes a modification under the 
statutory definition because it is reasonable to consider a change in 
the organic liquid stored to a new liquid with a higher true vapor 
pressure to be a change in operation, especially because such a change 
is expected to increase VOC emissions. Thus, the EPA proposes that a 
change in the liquid stored which results in increased VOC emissions 
would be a modification under NSPS subpart Kc. If the previous content 
of the storage vessel was below the vapor pressure threshold, a change 
in the liquid stored in the vessel to one that is above the vapor 
pressure threshold would increase the amount of VOC emitted from the 
storage vessel and should be considered a modification of the storage 
vessel and trigger the NSPS subpart Kc control requirements.
    The EPA solicits comment on the proposed change in interpretation 
of 40 CFR 60.14(e) as it applies to modifying storage vessels subject 
to NSPS subpart Kc.

H. What are the BSER and standards of performance for modified storage 
vessels with maximum true vapor pressures less than 11.1 psia?

    The EPA evaluated BSER for modified storage vessels for NSPS 
subpart Kc with maximum true vapor pressures less than 11.1 psia. In 
most cases, the EPA expects that modified storage vessels will have 
existing fixed roofs, because IFRs were not previously required by NSPS 
subpart Kb. The costs of retrofitting a fixed roof storage vessel with 
an IFR are the same as the costs of adding an IFR to a new storage 
vessel. Some modified storage vessels that newly trigger into the NSPS, 
however, may already have IFRs, and upgrading only certain elements of 
the IFR can have significantly different costs than when installing a 
new IFR. Therefore, to assess BSER for modified storage vessels, we 
developed national cost estimates separately for modified storage 
vessels depending on whether or not the storage vessels had existing 
IFRs prior to modification.
    We estimate a total of 30 storage vessels would become newly 
affected facilities due to modifications over the first 5 years after 
promulgation of NSPS subpart Kc. We estimate 10 percent of these 
storage vessels would have an existing IFR and that the existing IFR 
was compliant with the IFR requirements in NSPS subpart Kb. For more 
information on the nationwide cost analysis of IFR control options for 
modified storage vessels, see memorandum Control Options for Storage 
Vessels in Docket ID No. EPA-HQ-OAR-2023-0358.
    Table 5 of this preamble summarizes the costs and cost 
effectiveness of the impacts of modified storage vessels without an IFR 
prior to the modification, under the baseline of the existing Kb 
requirements and all three IFR options. The incremental costs are 
somewhat higher than for new and reconstructed storage vessels because 
we projected that the vapor pressures of the organic liquids stored in 
the modified storage vessels would be near the vapor pressure 
applicability threshold. Thus, we projected that storage vessels that 
triggered into the NSPS subpart Kc because of a change in the liquid 
stored would generally have lower vapor pressure organic liquids, on 
average, than compared to new storage vessels. Based on this analysis, 
we are proposing for NSPS subpart Kc to find that Option IFR-1 
(enhanced rim seal requirements) is cost-effective and represents BSER 
for modified fixed roof storage vessels. Like for new and reconstructed 
sources, the cost-effectiveness of all options is well within the range 
of what the EPA has considered to be cost-effective in past 
rulemakings. However, while the incremental cost effectiveness of 
Option IFR-1 is also reasonable, the incremental cost-effectiveness of 
Option IFR-2 and Option IFR-3 are significantly higher than what the 
EPA has previously found reasonable. Accordingly, while the cost-
effectiveness of all options is quite reasonable, the high incremental 
cost-effectiveness is the determining factor in the EPA's consideration 
of costs. The EPA's consideration of non-air quality health and 
environmental impacts, as well as energy requirements, is also the same 
as for new and reconstructed storage vessels. Therefore, the EPA is 
proposing to determine that Option IFR-1 is the BSER for existing 
storage vessels with maximum true vapor pressures less than 11.1 psia 
that modify and do not have an existing floating roof. These proposed 
requirements are also applicable to new sources (sources constructed 
after the proposal date) that modify after the proposal date.

[[Page 68546]]



 Table 5--Summary of National Impacts for Control Options for Modified Fixed Roof Storage Vessels With Maximum True Vapor Pressures Less Than 11.1 PSIA
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              TAC \3\
                                                           VOC emissions                      without      TAC \3\ with
                     Control option                        reduction \1\      TCI \2\         product         product      CE \4\ ($/ton  ICE \5\ ($/ton
                                                               (tpy)        (million $)    recovery ($/    recovery ($/        VOC)            VOC)
                                                                                                yr)             yr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Existing Kb.............................................             501           $2.32        $286,000      ($150,000)          ($299)          ($299)
Option IFR-1............................................             507            2.65         327,000       (114,000)           (224)           5,900
Option IFR-2............................................             510            3.18         392,000        (51,200)           (100)          21,100
Option IFR-3............................................             513            3.67         453,000           7,300              14          19,100
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Relative to uncontrolled fixed roof storage vessel.
\2\ Total Capital Investment (TCI).
\3\ Total annualized costs (TAC) considering annualized cost of capital.
\4\ Cost effectiveness.
\5\ Incremental cost effectiveness.

    Table 6 of this preamble summarizes the costs and cost 
effectiveness of the impacts of modified storage vessels with maximum 
true vapor pressures less than 11.1 psia that already have an existing 
IFR prior to the modification. The costs per ton of VOC reduced when 
modifying controls on an existing IFR are much higher than when 
installing a new IFR on an existing fixed roof storage vessel. The cost 
effectiveness and incremental cost effectiveness of all three IFR 
options are well above what the EPA has found to be reasonable for the 
control of VOC emissions. Consequently, we are proposing for NSPS 
subpart Kc that, for modified storage vessels with maximum true vapor 
pressures less than 11.1 psia with an existing IFR, the NSPS subpart Kb 
control requirements without upgrading the rim seal requirements 
represent the application of BSER, and we propose to retain those 
standards for these sources in NSPS subpart Kc.

                                Table 6--Summary of National Impacts for Control Options for Modified IFR Storage Vessels
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              TAC \2\
                                                           VOC emissions                      without      TAC \2\ with
                     Control option                          reduction      TCI \1\ ($)       product         product      CE \3\ ($/ton  ICE \4\ ($/ton
                                                               (tpy)                       recovery ($/    recovery ($/        VOC)            VOC)
                                                                                                yr)             yr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Existing Kb.............................................               0              $0              $0              $0              $0              $0
Option IFR-1............................................            0.48          64,000           7,900           7,480          15,700          15,700
Option IFR-2............................................            0.73         169,100          20,900          20,300          27,800          50,700
Option IFR-3............................................            0.87         254,600          31,400          30,700          35,300          74,600
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Total Capital Investment (TCI).
\2\ Total annualized costs (TAC) considering annualized cost of capital.
\3\ Cost effectiveness.
\4\ Incremental cost effectiveness.

    For existing EFR storage vessels, like existing IFR storage 
vessels, improvements to the floating roof and guidepole design would 
not result in significant additional emission reductions beyond those 
achieved by the use of the EFR itself. As a result, as for the IFR 
analysis just discussed, cost-effectiveness would be expected to be 
quite high such that the costs associated with the limited additional 
emission reductions would not be considered reasonable. Accordingly, we 
propose for NSPS subpart Kc, that if the modified tank has an existing 
EFR, the BSER and standard of performance is consistent with the EFR 
requirements as specified in NSPS subpart Kb.
    In very rare cases, a fixed roof storage vessel may already be 
vented through a closed vent system to a control device at the time 
that it undergoes a modification. In NSPS subpart Kb, the control 
requirement for these control devices is 95 percent. As discussed in 
section III.F. of this preamble, we are proposing to require storage 
vessels with maximum true vapor pressures equal to or greater than 11.1 
psia that are subject to NSPS subpart Kc to meet a 98 percent control 
efficiency based on a BSER identified as a closed vent system and 
control device. The primary difference between a flare, thermal 
oxidizer, or carbon adsorption system achieving 98 percent control 
efficiency rather than 95 percent control efficiency is largely in the 
operation of the control system rather than the design. Thus, we 
conclude that storage vessels that already vent through a closed vent 
system to a control device can technically achieve 98 percent control 
efficiency. As discussed in section III.F. of this preamble, we 
evaluated the incremental cost of operating a control system to achieve 
98 percent control efficiency compared to 95 percent control efficiency 
and determined that it is cost-effective to meet a 98 percent control 
requirement. We consider that the analysis in section III.F. of this 
preamble to also be applicable to modified storage vessels because 
there are no meaningful differences in the costs of achieving 98 
percent control efficiency as compared to new or reconstructed storage 
vessels. Therefore, for NSPS subpart Kc, we conclude that if a storage 
vessel with an existing closed vent system routed to a control device 
meets the qualifications for modification discussed in section III.G, 
the BSER is a closed vent system to a control device and standard of 
performance is 98 percent control of VOC emissions, the same as new or 
reconstructed storage vessels.
    The EPA solicits comment on the proposed standards for modified 
storage vessels, including whether the EPA should finalize any of the 
alternative options.

[[Page 68547]]

I. What control requirements are we proposing for IFR and EFR storage 
vessels emptying and degassing and why?

    Occasionally, floating roof storage vessels need to be taken out of 
service to clean, inspect, or repair the storage vessel or floating 
roof. For example, some floating roof seal components may wear out more 
quickly over time than the main structure of the floating roof. 
Depending on the seal type, this repair may require that the storage 
vessel be taken out of service. When the storage vessel is emptied, the 
floating roof will land on support legs or, if suspended by cables, 
reach a fixed height position. Commonly, the support legs or cable 
suspension will have two different fixed settings. One setting would be 
at a low height (for example, one foot) to maximize the working volume 
of the storage vessel when it is in service. The other setting would be 
a high ``maintenance'' height that allows maintenance crews to enter 
the storage vessel and walk under the roof once the floating roof is 
landed and the storage vessel is emptied. The vapor space can have 
significant volatile content due to volatilization of the organic 
liquid as the storage vessel is emptied or from liquid film that may 
cling to the wall and floor after the tank is emptied. The VOC 
emissions from the emptying and degassing process is dependent on the 
vapor pressure of the liquid stored, the dimensions of the storage 
vessel, and the height of the floating roof when landed (for 
maintenance), which impacts the size of the vapor space below the 
floating roof. The EPA evaluated different scenarios in which a control 
device could be utilized to achieve a 98 percent destruction efficiency 
until the vapor space concentration is within 10 percent of the lower 
explosive limit (LEL).
    We evaluated the cost and VOC emissions for a wide variety of 
storage vessel sizes and VOL contents. We found that degassing controls 
were generally only cost-effective for larger storage vessels with 
vapor pressures greater than 1.5 psia. We evaluated the following 
options to determine the applicability threshold for control during 
degassing events:
     Baseline: Uncontrolled degassing.
     Degassing Option 1: Control degassing for storage vessels 
with a capacity of 1-million gallon or more storing organic liquids 
with a maximum true vapor pressure of 1.5 psia or more.
     Degassing Option 2a: Control degassing for storage vessels 
with a capacity of 300,000 gallon or more storing organic liquids with 
a maximum true vapor pressure of 1.5 psia or more.
     Degassing Option 2b: Control degassing for storage vessels 
with a capacity of 1-million gallon or more storing organic liquids 
with a maximum true vapor pressure of 0.5 psia or more.
    Degassing Options 2a and 2b were both evaluated against Degassing 
Option 1 to evaluate whether lowering the size threshold or lowering 
the vapor pressure threshold could be cost- effective. Nationwide 
impacts were estimated based on our projected distribution of storage 
vessels. Furthermore, we estimated that storage vessels would be 
emptied and degassed once every 10 years. For more details regarding 
the nationwide estimated of degassing emissions and costs and emission 
reductions for degassing controls, see memorandum Control Options for 
Storage Vessels in Docket ID No. EPA-HQ-OAR-2023-0358. The nationwide 
impacts projected for the degassing control options are summarized in 
Table 7 of this preamble. We evaluated the cost effectiveness and 
incremental cost effectiveness of the three different options. While 
all three options were cost-effective, degassing option 1 was selected 
because the incremental cost effectiveness of the remaining options 
exceeded reasonable values established for the control of VOC emissions 
in prior rulemaking. Based on our analysis, we are proposing that, for 
degassing emissions, a control device utilized to achieve a 98 percent 
destruction efficiency is the BSER for storage vessels with a capacity 
of 1-million gallon or more storing organic liquids with a maximum true 
vapor pressure of 1.5 psia or more. The EPA's consideration of non-air 
quality health and environmental impacts as well as energy requirements 
is the same as considered for control devices in section III.F. 
Accordingly, the EPA proposes to establish a standard of performance of 
98 percent control until the vapor space concentration is within 10 
percent of the LEL for these storage vessels that applies during 
degassing events.
    The EPA solicits comment on the proposed BSER and standard of 
performance for degassing events, including the applicability threshold 
for application of those standards.

                           Table 7--Summary of National Impacts for Degassing Controls
----------------------------------------------------------------------------------------------------------------
                                                                      TAC \1\
                                                   VOC emissions      without
         Control option            VOC emissions     reduction        product      CE \2\ ($/ton  ICE \3\ ($/ton
                                       (tpy)           (tpy)         recovery          VOC)            VOC)
                                                                  (million $/yr)
----------------------------------------------------------------------------------------------------------------
Baseline........................           33.30  ..............  ..............  ..............  ..............
Degassing Option 1..............           18.92           14.38         $69,860          $4,859  ..............
Degassing Option 2a.............           14.89           18.41         119,000           6,465         $12,196
Degassing Option 2b.............           13.38           19.92         129,740           6,514          10,809
----------------------------------------------------------------------------------------------------------------
\1\ Total annualized costs (TAC) considering annualized cost of capital.
\2\ Cost effectiveness (CE).
\3\ Incremental cost effectiveness (ICE). The ICE of Degassing Options 2a and 2b are calculated against
  Degassing Option 1.

J. What requirements are we proposing for storage vessel testing, 
monitoring, and inspections and why?

    Because the NSPS reflects BSER under conditions of proper operation 
and maintenance, in doing our review, we also evaluate and determine 
the proper testing, monitoring, recordkeeping and reporting 
requirements needed to ensure compliance with the requirements of NSPS 
subpart Kc. This section includes our discussion on current testing and 
monitoring requirements of the NSPS subpart Kb and any revisions or 
additions we are proposing to include for NSPS subpart Kc.
    We reviewed and compared monitoring and inspection requirements 
across several rules, including NSPS subpart Kb and the storage vessel 
requirements in 40 CFR part 63, subpart WW and 40 CFR part 65, subpart 
C. Generally, these requirements are similar to each other, and we 
strove to develop monitoring and inspection requirements consistent 
with these federal standards and that provide the best clarity for the 
specific requirements. However, we note that the

[[Page 68548]]

current NSPS subpart Kb includes provision for inspections every 5 
years for IFRs that have a dual seal system. We are proposing to 
require dual seal IFRs for storage vessels with a maximum vapor 
pressure less than 11.1 psia, but as discussed later in this section, 
we are also proposing the use of lower explosive limit (LEL) monitoring 
within the headspace of the IFR as a means to enhance inspections and 
more readily identify malfunctioning internal floating roofs. Because a 
top-side inspection can be easily conducted in conjunction with the 
annual LEL monitoring, we are proposing to require annual LEL 
monitoring and floating roof inspections for all floating roofs, 
including IFRs with a dual seal system.
    We are proposing to add annual monitoring of IFR storage vessels 
using a LEL monitor to identify floating roofs with poorly functioning 
seals or fitting controls. We identified at least two States or 
localities (New Jersey rule 7:27-16 and SCAQMD Rule 1178) that have LEL 
monitoring for IFR storage vessels. Our emission estimates from various 
storage vessel requirements assume that proper seals and other 
equipment are in-place and operating as required. If these controls are 
not operating as intended, the emissions from these storage vessels can 
be much higher. We found that the visual inspections are subjective and 
may, at times, not be performed well. For example, although a hired 
contractor for BP's Carson Refinery had reported no problems with the 
facility's 26 floating roof storage vessels from 1994 to 2002, a SCAQMD 
inspection ``revealed that more than 80 percent of the storage vessels 
had numerous leaks, gaps, torn seals, and other defects that caused 
excess emissions.'' \8\ Therefore, for purposes of NSPS subpart Kc, we 
sought a less subjective means to monitor and verify performance of the 
floating roofs. We concluded that periodic LEL monitoring could be used 
to ensure the floating roofs are performing as intended.
---------------------------------------------------------------------------

    \8\ Mokhiber, Russell. Multinational Monitor; Washington Vol. 
24, Iss. 4, (April 2003): 30.
---------------------------------------------------------------------------

    The New Jersey and SCAQMD rules set a maximum LEL that triggers an 
obligation for corrective action at the storage vessel, and we modeled 
our proposed NSPS subpart Kc provision following these State rules. For 
storage vessels installed after June 1, 1984, these rules set a maximum 
LEL of 30 percent. However, the National Fire Protection Association 
(NFPA) standard sets a maximum LEL of 25 percent for explosion 
prevention for IFR storage vessels. Per our review, we conclude that 
establishing a maximum LEL level for IFR storage vessels in NSPS 
subpart Kc that will trigger an obligation for the owner and operator 
to repair the IFR, discussed further in the next paragraph, which will 
ensure the emission reductions expected by the application of BSER are 
achieved. From the data we collected, there were very few measurements 
that exceeded 25 percent LEL that did not also exceed 50 percent LEL. 
Thus, when failures occurred, the LEL was often very high. Based on 
these observations and considering the more stringent NFPA standard, we 
propose for NSPS subpart Kc, for new, modified, and reconstructed 
storage vessels, the use of LEL monitor to identify floating roofs with 
poorly functioning seals or fitting controls and we propose that the 
appropriate LEL levels for IFR storage vessels is 25 percent.
    We acknowledge that it is difficult to estimate the emission 
impacts of these LEL monitoring requirements because we do not have 
data on the number of poorly functioning floating roofs. NSPS subpart 
Kb already requires repair of floating roofs that fail inspection and 
failure of the proposed NSPS subpart Kc LEL monitoring would trigger 
the same repairs. As such, we consider that these repairs are already 
required in NSPS subpart Kb and the LEL requirement predominately makes 
the required inspections less subjective. In the worst-case scenario, a 
poorly operated IFR storage vessel can have emissions similar to those 
of a fixed roof storage vessel. In establishing the floating roof 
requirements, we already determined that installing a floating roof was 
cost-effective and that the costs of replacing a poorly functioning 
floating roof is not significantly different from the costs of 
retrofitting a fixed roof storage vessel. In our cost analysis, we 
projected floating roofs have a 15-year life, so our annualized costs 
account for IFR replacement every 15 years. We expect that most poorly 
performing floating roofs can be repaired, rather than replaced, but we 
expect that replacement will be necessary in some cases. We propose to 
require in NSPS subpart Kc that for new, modified, and reconstructed 
storage vessels whose IFRs have failed to the point that 25 percent LEL 
is exceeded, the owner or operator must repair the IFR and, if 
necessary, to replace the IFR when repairs are ineffective.
    We are proposing in NSPS subpart Kc specific testing requirements 
when monitoring LEL for storage vessels with IFRs. We are proposing 
that LEL standard be assessed on a 5-minute rolling average basis and 
that LEL monitoring be conducted for a minimum of 20 minutes unless an 
exceedance is measured prior to completing 20 minutes of LEL 
monitoring. We are proposing that LEL be measured within the storage 
vessel no more than 3 feet above the IFR. We are proposing that LEL 
monitoring be conducted when the wind speed at the top of the tank is 5 
miles per hour or less where practicable, but the testing will be 
invalid and must be reconducted at a later date (no later than 30 days 
from the previous attempted measurement) if the wind speed at the top 
of the tank is greater than the annual average wind speed at the site's 
location or 15 miles per hour, whichever is less.
    The EPA solicits comment on the proposed testing, monitoring, and 
inspection requirements, including whether our selection of maximum 25 
percent LEL is appropriate, or whether this number should be higher or 
lower.
    There are a number of other monitoring and inspection requirements 
included as part of this proposal. The EPA is proposing 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 is proposing quarterly visual, 
audible, and olfactory inspections, annual EPA Method 21 instrument 
monitoring, and monitoring of bypasses. The EPA also proposes that 
storage vessels using closed vent systems and control devices must 
equip pressure relief devices with appropriate monitoring to identify 
releases.
    The EPA is proposing specific requirements for flare and non-flare 
control devices to ensure they achieve the required control efficiency 
on an ongoing basis. Specifically, we are proposing initial testing of 
non-flare control devices and periodic testing every five years. During 
the performance test, the owner or operator would set an operating 
limit on the control device; continuous compliance with the operating 
limit would be demonstrated on a 3-hour rolling average basis. We 
propose that flares would be monitored consistent with the flare 
requirements in 40 CFR part 63 subpart CC.
    Lastly the EPA is proposing applying the requirements in 40 CFR 
60.116b(f) for waste mixtures to all mixtures with indeterminate or 
variable compositions.

K. Proposal of NSPS Subpart Kc Without Startup, Shutdown, and 
Malfunction Exemptions

    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), the United States Court of Appeals for the District of 
Columbia Circuit (D.C.

[[Page 68549]]

Circuit) vacated portions of two provisions in the EPA's CAA section 
112 regulations governing the emissions of HAP during periods of SSM. 
Specifically, the Court vacated the SSM exemption contained in 40 CFR 
63.6(f)(1) and (h)(1), holding that under section 302(k) of the CAA, 
emissions standards or limitations must be continuous in nature and 
that the SSM exemption violates the CAA's requirement that some section 
112 standard apply continuously. The EPA has determined the reasoning 
in the Court's decision in Sierra Club applies equally to CAA section 
111 because the definition of emission or standard in CAA section 
302(k), and the embedded requirement for continuous standards, also 
applies to the NSPS.
    Consistent with Sierra Club v. EPA, we are proposing standards in 
this rule that apply at all times. The NSPS general provisions in 40 
CFR 60.11(c) currently exclude opacity requirements during periods of 
SSM and the provision in 40 CFR 60.8(c) contains an exemption from non-
opacity standards. We are proposing in NSPS subpart Kc specific 
requirements at 40 CFR 60.112c(a)(1) that override the general 
provisions for SSM provisions. We are proposing a combination of 
design, equipment, work practice, and operational standards in NSPS 
subpart Kc that apply at all times.
    The EPA has attempted to ensure that the general provisions we are 
proposing to override are inappropriate, unnecessary, or redundant in 
the absence of the SSM exemption. We are specifically seeking comment 
on whether we have successfully done so.
    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 case law 
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 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).]
    In the event that a source fails to comply with the applicable CAA 
section 111 standards as a result of a malfunction event, the EPA would 
determine an appropriate response based on, among other things, the 
good faith efforts of the source to minimize emissions during 
malfunction periods, including preventative and corrective actions, as 
well as root cause analyses to ascertain and rectify excess emissions. 
The EPA would also consider whether the source's failure to comply with 
the CAA section 111 standard was, in fact, sudden, infrequent, not 
reasonably preventable, and was not instead caused, in part, by poor 
maintenance or careless operation. 40 CFR 60.2 (definition of 
``Malfunction'').
    If the EPA determines in a particular case that an enforcement 
action against a source for violation of an emission standard is 
warranted, the source can raise any and all defenses in that 
enforcement action and the Federal District Court will determine what, 
if any, relief is appropriate. The same is true for citizen enforcement 
actions. Similarly, the presiding officer in an administrative 
proceeding can consider any defense raised and determine whether 
administrative penalties are appropriate.
    In summary, the EPA proposes that its interpretation of the CAA 
and, in particular, CAA section 111 is reasonable and encourages 
practices that will avoid malfunctions. Administrative and judicial 
procedures for addressing exceedances of the standards fully recognize 
that violations may occur despite good faith efforts to comply and can 
accommodate those situations. U.S. Sugar Corp. v. EPA, 830 F.3d 579, 
606-610 (2016).

L. Electronic Reporting

    The EPA is proposing that owners and operators of volatile organic 
liquid storage vessels (including petroleum liquid storage vessels) 
subject to NSPS subpart Kb and NSPS subpart Kc, submit electronic 
copies of certain required notifications and reports through the EPA's 
Central Data Exchange (CDX) using the Compliance and Emissions Data 
Reporting Interface (CEDRI). A description of the electronic data 
submission process is provided in the memorandum Electronic Reporting 
Requirements for New Source Performance Standards (NSPS) and National 
Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, 
available in the docket for this action. Specifically, the proposed 
rule requires that for NSPS subpart Kb the reports specified in 40 CFR 
60.115b(a)(1), 60.115b(a)(3), 60.115b(a)(4), 60.115b(b)(1), 
60.115b(b)(2), 60.115b(b)(4), 60.115b(d)(1), 60.115b(d)(3), and 
60.116b(d) be submitted as a portable document format upload in CEDRI, 
and for NSPS subpart Kc the rule requires that owners and operators use 
the appropriate spreadsheet templates to submit the initial 
notification specified in 40 CFR 60.116c(a) and semiannual reports 
specified in 40 CFR 60.116c(b) to CEDRI. Draft versions of the proposed 
templates for the NSPS subpart Kc initial notification and semiannual 
report are included in the docket for this action.\9\ The EPA 
specifically requests comment on the content, layout, and overall 
design of the templates. We note that for NSPS subpart Kb, we are only 
proposing to change the format of the reporting requirements to require 
electronic reporting (i.e., we are not proposing any new data 
elements).
---------------------------------------------------------------------------

    \9\ See 40 CFR 
part_60_Subpart_Kc_60.116c(a)_Initial_Notification.xlsx and 40 CFR 
part_60_subpart_Kc_60.116c(b)_Semiannual_Report.xlsx, available in 
the docket for this action.
---------------------------------------------------------------------------

    Additionally, the EPA has identified two broad circumstances in 
which electronic reporting extensions may be provided. These 
circumstances are (1) outages of the EPA's CDX or CEDRI which preclude 
an owner or operator from accessing the system and submitting required 
reports and (2) force majeure events, which are defined as events that 
will be or have been caused by circumstances beyond the control of the 
affected facility, its contractors, or any entity controlled by the 
affected facility that prevent an owner or operator from complying with 
the requirement to submit a report electronically. Examples of force 
majeure events are acts of nature, acts of war or terrorism, or 
equipment failure or safety hazards beyond the control of the facility. 
The EPA is providing these potential extensions to protect owners and 
operators from noncompliance in

[[Page 68550]]

cases where they cannot successfully submit a report by the reporting 
deadline for reasons outside of their control. In both circumstances, 
the decision to accept the claim of needing additional time to report 
is within the discretion of the Administrator, and reporting should 
occur as soon as possible.
    The electronic submittal of the reports addressed in this proposed 
rulemaking will increase the usefulness of the data contained in those 
reports, is in keeping with current trends in data availability and 
transparency, will further assist in the protection of public health 
and the environment, will improve compliance by facilitating the 
ability of regulated facilities to demonstrate compliance with 
requirements and by facilitating the ability of delegated State, local, 
Tribal, and territorial air agencies and the EPA to assess and 
determine compliance, and will ultimately reduce burden on regulated 
facilities, delegated air agencies, and the EPA. Electronic reporting 
also eliminates paper-based, manual processes, thereby saving time and 
resources, simplifying data entry, eliminating redundancies, minimizing 
data reporting errors, and providing data quickly and accurately to the 
affected facilities, air agencies, the EPA, and the public. Moreover, 
electronic reporting is consistent with the EPA's plan \10\ to 
implement Executive Order 13563 and is in keeping with the EPA's 
agency-wide policy \11\ developed in response to the White House's 
Digital Government Strategy.\12\ For more information on the benefits 
of electronic reporting, see the memorandum Electronic Reporting 
Requirements for New Source Performance Standards (NSPS) and National 
Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, 
referenced earlier in this section.
---------------------------------------------------------------------------

    \10\ EPA's Final Plan for Periodic Retrospective Reviews, August 
2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \11\ E-Reporting Policy Statement for EPA Regulations, September 
2013. Available at: https://www.epa.gov/sites/default/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
    \12\ Digital Government: Building a 21st Century Platform to 
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
---------------------------------------------------------------------------

M. Other Proposed Actions

    NSPS subpart Kb includes a number of technical methods which have 
been updated or replaced in the NSPS subpart Kc proposal. Two of these 
methods, American Society for Testing and Materials (ASTM) D2879 and 
American Petroleum Institute (API) Bulletin 2517, are used in 
determining vapor pressures including the maximum true vapor pressure.
    We propose to replace ASTM D2879, ``Standard Test Method for Vapor 
Pressure-Temperature Relationship and Initial Decomposition Temperature 
of Liquids by Isoteniscope,'' with both ASTM D6378-22, ``Standard Test 
Method for Determination of Vapor Pressure (VPX) of Petroleum Products, 
Hydrocarbons, and Hydrocarbon-Oxygenate Mixtures (Triple Expansion 
Method),'' and ASTM D6377-20 ``Standard Test Method for Determination 
of Vapor Pressure of Crude Oil: VPCRx (Expansion Method).'' 
This change is consistent with the actions finalized in the 2020 
amendments to the Organic Liquids Distribution (OLD) NESHAP (85 FR 
40740). ASTM D2879 involves both an isoteniscope and heating the sample 
to a boil. The proposed replacement is an automated device method that 
produces more accurate vapor pressure measurements. ASTM D6378-22 is 
used for measuring vapor pressures between 7 kPa and 150 kPa. ASTM 
D6377-20 is used for measuring vapor pressures between 29 kPa and 180 
kPa. For each analysis, you must use a 4:1 vapor to liquid ratio.
    Additionally, we propose replacing the API Bulletin 2517, 
Evaporative Loss from External Floating-Roof Tanks, with information 
available in AP-42, Chapter 7. While API Bulletin 2517 does not 
prescribe methods for measuring liquid vapor pressure, it acts as a 
reference and includes a table of vapor pressures for pure substances 
at temperatures between 40 and 100 degrees Fahrenheit. API Bulletin 
2517 also includes information for calculating Reid vapor pressures 
crude oil and refined petroleum stocks. AP-42, Chapter 7 includes 
comparable information and is publicly available. EPA is also proposing 
not to incorporate ASTM D323 into the proposed subpart. ASTM D323, 
``Standard Test Method for Vapor Pressure of Petroleum Products (Reid 
Method)'' is used for the determination of the Reid vapor pressure 
which can be used in conjunction with ASTM D2879 for determining vapor 
pressures. The inclusion of ASTM D6378 and ASTM D6377, makes the need 
for ASTM D323 unnecessary in the proposed standard.

N. Compliance Dates

    Pursuant to CAA section 111(b)(1)(B), the effective date of the 
final rule requirements in NSPS 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 
NSPS subpart Kc, no later than the effective date of the final rule or 
upon startup, whichever is later. The EPA is proposing 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.

IV. Summary of Cost, Environmental, and Economic Impacts

A. What are the air quality impacts?

    The proposed revisions in NSPS subpart Kc reduce emissions of VOCs, 
some of which may also be hazardous air pollutants (HAPs). The EPA 
estimates that the updated standards would 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.

B. What are the cost impacts?

    This final action will cost (in 2022 dollars) approximately $20.6 
million in total capital cost and result in total annualized cost 
savings of $4.48 million per year (including product recovery) based on 
our analysis of the proposed actions in NSPS subpart Kc. More 
information about the estimated cost of the proposed actions can be 
found in the memorandum Control Options for Storage Vessels.

C. What are the economic impacts?

    For economic impact analyses of rules that directly affect a single 
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 to not be 
considered in the analysis. If the compliance costs, which are key 
inputs to an economic impact analysis, 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 economic impact analysis 
approach is deemed not

[[Page 68551]]

necessary given the expected size of the impacts.
    The net present value of the estimated cost impacts of the proposed 
NSPS subpart Kc is $18.9 million, discounted at a 3 percent rate over a 
5-year analytic time frame from 2024 to 2028 in 2022 dollars. Using a 7 
percent discount rate, the net present value of the estimated cost 
impacts is $16.9 million. The equivalent annualized value in 2022 
dollars is a cost of approximately $4.1 million using a discount rate 
of three and seven percent.
    Storage vessels in NSPS subpart Kb are most closely associated with 
the petroleum and coal products industry (NAICS 324000), chemical 
products industry (NAICS 325000), and the petroleum bulk stations 
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 $129 to $440 billion per sector, to the 
national economy. In comparison, the proposed requirements in NSPS 
subpart Kc have estimated total costs of $20.6 million. The total cost 
is the total incurred collectively amongst numerous sectors, and each 
of the sectors examined have sales of at least $129 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 
proposed rule, and there will not be substantial impacts on the markets 
for affected products. The costs of the proposed 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?

    These proposed revisions 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 proposed 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?

    Executive Order 12898 directs the EPA to identify the populations 
of concern who are most likely to experience unequal burdens from 
environmental harms, which are specifically minority populations 
(people of color), low-income populations, and Indigenous peoples (59 
FR 7629, February 16, 1994). Additionally, Executive Order 13985 is 
intended to advance racial equity and support underserved communities 
through Federal government actions (86 FR 7009, January 20, 2021). The 
EPA defines environmental justice (EJ) as ``the fair treatment and 
meaningful involvement of all people regardless of race, color, 
national origin, or income, with respect to the development, 
implementation, and enforcement of environmental laws, regulations, and 
policies.'' \13\ The EPA further defines fair treatment to mean that 
``no group of people should bear a disproportionate burden of 
environmental harms and risks, including those resulting from the 
negative environmental consequences of industrial, governmental, and 
commercial operations or programs and policies.'' In recognizing that 
people of color and low-income populations often bear an unequal burden 
of environmental harms and risks, the EPA continues to consider ways of 
protecting them from adverse public health and environmental effects of 
air pollution. For purposes of analyzing regulatory impacts, the EPA 
relies upon its June 2016 ``Technical Guidance for Assessing 
Environmental Justice in Regulatory Analysis,'' \14\ 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 minority populations, low-income 
populations, and/or Indigenous peoples; (2) exacerbate existing 
disproportionate impacts on minority populations, low-income 
populations, and/or Indigenous peoples; or (3) present opportunities to 
address existing disproportionate impacts on minority populations, low-
income populations, and/or Indigenous peoples through this action under 
development.
---------------------------------------------------------------------------

    \13\ https://www.epa.gov/environmentaljustice.
    \14\ See https://www.epa.gov/environmentaljustice/technical-guidance-assessing-environmental-justice-regulatory-analysis.
---------------------------------------------------------------------------

    We are unable to quantitatively estimate the potential EJ impact of 
NSPS subparts Kb and Kc for the following reasons. Over the next 5 
years, the EPA estimates that 1,440 new tanks and 27 modified tanks 
would be subject to NSPS subpart Kc. However, the locations of any new 
VOL storage vessels that would be subject to NSPS subpart Kc are 
unknown. Furthermore, there is insufficient data available regarding 
the locations of existing VOL storage vessels. We estimate that there 
are approximately more than 10,000 existing Volatile Organic Liquid 
Storage Vessels, but do not have a list of specific units 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 are not able to 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.
    However, we anticipate the proposed requirements in NSPS subpart Kc 
would generally minimize future emissions in surrounding communities of 
new, modified, or reconstructed VOL storage vessels. The three most 
relevant industry NAICS industry segments affected under NSPS Kc 
include Petroleum and Coal Products Manufacturing (NAICS code 324000), 
Chemical Manufacturing (NAICS code 325000), and Petroleum and Bulk 
Stations and Terminals (NAICS code 422710). Specifically, the EPA 
determined that the standards should be revised to amend the vapor 
pressure applicability thresholds, require stricter seal requirements 
on IFR tanks, establish equivalent control requirements for external 
floating roofs, and strengthen the closed vent system standard to 
account for 98 percent destruction efficiency. The changes would have 
beneficial effects on air quality and public health for populations 
exposed to emissions from new, modified or reconstructed VOL storage 
vessels and would provide additional health protection for affected 
populations, including communities already overburdened by pollution, 
which are often people of color, low-income, and indigenous 
communities.

V. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive orders 
can be

[[Page 68552]]

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 and was 
therefore not submitted to the Office of Management and Budget (OMB) 
for review.

B. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(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 EPA is proposing 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.
    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.
    Submit your comments on the Agency's need for this information, the 
accuracy of the provided burden estimates and any suggested methods for 
minimizing respondent burden to the EPA using the docket identified at 
the beginning of this rule. You may also send your ICR-related comments 
to OMB's Office of Information and Regulatory Affairs via email to 
[email protected], Attention: Desk Officer for the EPA. Since 
OMB is required to make a decision concerning the ICR between 30 and 60 
days after receipt, OMB must receive comments no later than November 3, 
2023. The EPA will respond to any ICR-related comments in the 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. 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 Proposed 
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 would 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 proposed 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 tanks 
in excess of 20,000 gallons that meet the vapor pressure cutoffs for 
general rule applicability or control applicability. The NSPS subpart 
Kc proposal includes some updates to the VOC standards and monitoring 
requirements for storage vessels that meet the revised vapor pressure 
cutoffs for control. Additionally, basic requirements for recordkeeping 
and good air pollution control practices are being proposed for all 
storage vessels greater than 20,000. These changes would 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 will offer government-to-
government consultation with tribes and will conduct additional 
outreach to inform them of the content of the proposed rule.

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

    Executive Order 13045 (62 FR 19885, April 23, 1997) 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. These proposed 
revisions would reduce emissions of VOCs, some of which may also be 
hazardous air pollutants (HAPs). These standards would help to reduce 
atmospheric ozone concentrations and reduce health effects associated 
with high levels of ozone.
    However, EPA's Policy on Children's Health applies to this action. 
Information on how the Policy was applied is available under 
``Children's Environmental Health'' in the SUPPLEMENTARY INFORMATION 
section of this preamble.

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 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

[[Page 68553]]

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 (VCS) for this rule. Although there were 
no applicable voluntary consensus standards identified, we are amending 
40 CFR 60.17 to incorporate by reference two ASTM methods as discussed 
in section III.M. These include the following:
     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.
     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, 
hydrocarbons and liquid petroleum products sampled at a 4:1 vapor-
liquid ratio.
    The ASTM standards are available from the American Society for 
Testing and Materials (ASTM), 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 27 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 is also not known. The EPA estimates that there are 
approximately more than 10,000 existing vessels subject to NSPS subpart 
Kb, but do not have a list of specific units 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 are not able to 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 in section IV.E. All pertinent supporting documents such as the 
technical memo, ``Control Options for Storage Vessels'' which discusses 
the costs and environmental impacts of the regulatory options 
considered have been placed in the docket.

Michael S. Regan,
Administrator.
[FR Doc. 2023-21976 Filed 10-3-23; 8:45 am]
BILLING CODE 6560-50-P


