83296 Federal Register / Vol. 89, No. 199 / Tuesday, October 15, 2024 / Rules and Regulations 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 60 

[EPA–HQ–OAR–2023–0358; FRL–10655–02– 

OAR] 

RIN 2060–AV93 

New Source Performance Standards 

Review for Volatile Organic Liquid 

Storage Vessels (Including Petroleum 

Liquid Storage Vessels) 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is finalizing amendments 

to the new source performance 

standards (NSPS) for Volatile Organic 

Liquid Storage Vessels (Including 

Petroleum Liquid Storage Vessels) 

pursuant to the review required by the 

Clean Air Act (CAA). The EPA is 

finalizing revisions to the NSPS that are 

applicable to volatile organic liquid 

(VOL) storage vessels that commence 

construction, reconstruction, or 

modification after October 4, 2023, 

under a new NSPS subpart, as well as 

amendments to an existing subpart. In 

the new NSPS subpart Kc, the EPA is 

finalizing requirements to reduce the 

vapor pressure applicability thresholds 

and revise the volatile organic 

compound (VOC) standards to reflect 

the best system of emission reduction 

(BSER) for affected storage vessels. In 

addition, the EPA is finalizing degassing 

emission controls; clarification of 

startup, shutdown, and malfunction 

(SSM) requirements; additional 

monitoring requirements; and other 

technical improvements 

DATES: This final rule is effective on 

October 15, 2024. The incorporation by 

reference of certain publications listed 

in the rule is approved by the Director 

of the Federal Register as of October 15, 

2024. 

ADDRESSES: The EPA has established a 

docket for this action under Docket ID 

No. EPA–HQ–OAR–2023–0358. All 

documents in the docket are listed on 

the https://www.regulations.gov 

website. Although listed, some 

information is not publicly available, 

e.g., Confidential Business Information 

(CBI) or other information whose 

disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the internet and will be publicly 

available only as portable document 

format (PDF) versions that can only be 

accessed on the EPA computers in the 

docket office reading room. Certain 

databases and physical items cannot be 

downloaded from the docket but may be 

requested by contacting the Public 

Reading Room at (202) 566–1744. The 

docket office has up to 10 business days 

to respond to these requests. With the 

exception of such material, publicly 

available docket materials are available 

electronically in Regulations.gov or on 

the EPA computers in the Public 

Reading Room at the EPA Docket 

Center, WJC West Building, Room 

Number 3334, 1301 Constitution Ave. 

NW, Washington, DC. The Public 

Reading Room hours of operation are 

8:30 a.m. to 4:30 p.m. Eastern Standard 

Time (EST), Monday through Friday. 

The telephone number for the Public 

Reading Room is (202) 566–1744, and 

the telephone number for the EPA 

Docket Center is (202) 566–1742. 

FOR FURTHER INFORMATION CONTACT: Mr. 

Michael Cantoni III, Sector Policies and 

Programs Division (E143–01), Office of 

Air Quality Planning and Standards, 

U.S. Environmental Protection Agency, 

109 T.W. Alexander Drive, P.O. Box 

12055, Research Triangle Park, North 

Carolina 27711; telephone number: 

(919) 541–5593; and email address: 

cantoni.michael@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Preamble acronyms and 

abbreviations. Throughout this 

document the use of ‘‘we,’’ ‘‘us,’’ or 

‘‘our’’ is intended to refer to the EPA. 

We use multiple acronyms and terms in 

this preamble. While this list may not be 

exhaustive, to ease the reading of this 

preamble and for reference purposes, 

the EPA defines the following terms and 

acronyms here: 

AMEL alternative means of emissions 

limitation 

API American Petroleum Institute 

ASTM American Society for Testing and 

Materials 

AVO audible, visual, and olfactory 

BSER best system of emission reduction 

CAA Clean Air Act 

CBI Confidential Business Information 

CDX Central Data Exchange 

CEDRI Compliance and Emissions Data 

Reporting Interface 

CFR Code of Federal Regulations 

EFR external floating roof 

EIA economic impact analysis 

EJ environmental justice 

EPA Environmental Protection Agency 

FR Federal Register 

gal gallons 

HAP hazardous air pollutant(s) 

IBR incorporate by reference 

ICR information collection request 

IFR internal floating roof 

kg/hr kilograms per hour 

kPa kilopascals 

LEL lower explosive limit 

m3 cubic meters 

MON Miscellaneous Organic Chemical 

Manufacturing NESHAP 

MTVP maximum true vapor pressure 

NAICS North American Industry 

Classification System 

NESHAP national emission standards for 

hazardous air pollutants 

NSPS new source performance standards 

NTAA National Tribal Air Association 

NTTAA National Technology Transfer and 

Advancement Act 

OMB Office of Management and Budget 

PDF portable document format 

PRA Paperwork Reduction Act 

PRD pressure relief device 

ppmv parts per million by volume 

psia pounds per square inch absolute 

psig pounds per square inch gauge 

RFA Regulatory Flexibility Act 

RIN Regulatory Information Number 

SCAQMD South Coast Air Quality 

Management District 

SSM startup, shutdown, and malfunction 

STERPP 2000 U.S. EPA Storage Tank 

Emission Reduction Partnership Program 

UMRA Unfunded Mandates Reform Act 

VCU vapor combustion unit 

VOC volatile organic compound(s) 

VOL volatile organic liquid 

Organization of this document. The 

information in this preamble is 

organized as follows: 

I. General Information 

A. Does this action apply to me? 

B. Where can I get a copy of this document 

and other related information? 

C. Judicial Review and Administrative 

Review 

II. Background 

A. What is the statutory authority for this 

action? 

B. How does the EPA perform the NSPS 

review? 

C. What is the source category regulated in 

this final action? 

D. What outreach and engagement did the 

EPA conduct? 

III. What changes did we propose for the VOL 

Storage Vessel NSPS? 

IV. What actions are we finalizing and what 

is our rationale for such decisions? 

A. Revised NSPS for VOL Storage Vessels 

That Commenced Construction, 

Reconstruction, or Modification After 

July 23, 1984, and on or Before October 

4, 2023 

B. Revised NSPS for VOL Storage Vessels 

That Commenced Construction, 

Reconstruction, or Modification After 

October 4, 2023 

C. NSPS Subpart Kc Without Startup, 

Shutdown, and Malfunction Exemptions 

D. Testing, Monitoring, and Inspection 

Requirements 

E. Recordkeeping and Electronic Reporting 

F. Other Final Amendments 

G. Effective Date and Compliance Dates 

V. Summary of Cost, Environmental, and 

Economic Impacts 

A. What are the air quality impacts? 

B. What are the cost impacts? 

C. What are the economic impacts? 

D. What are the benefits? 

E. What analysis of environmental justice 

did we conduct? 

VI. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 


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Federal Register / Vol. 89, No. 199 / Tuesday, October 15, 2024 / Rules and Regulations 83297 

Order 14094: Modernizing Regulatory 

Review 

B. Paperwork Reduction Act (PRA) 

C. Regulatory Flexibility Act (RFA) 

D. Unfunded Mandates Reform Act 

(UMRA) 

E. Executive Order 13132: Federalism 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

I. National Technology Transfer and 

Advancement Act (NTTAA) and 1 CFR 

Part 51 

J. Executive Order 12898: Federal Actions 

To Address Environmental Justice in 

Minority Populations and Low-Income 

Populations and Executive Order 14096: 

Revitalizing Our Nation’s Commitment 

to Environmental Justice for All 

K. Congressional Review Act (CRA) 

I. General Information 

A. Does this action apply to me? 

The source category that is the subject 

of this final action is composed of VOL 

storage vessels (including petroleum 

liquid storage vessels) regulated under 

CAA section 111, NSPS. The 2022 North 

American Industry Classification 

System (NAICS) codes for the source 

category are 325, 324, and 422710. The 

NAICS codes serve as a guide for 

readers outlining the type of entities 

that this final action is likely to affect. 

The NSPS codified in 40 CFR part 60, 

subpart Kc, are directly applicable to 

affected facilities that begin 

construction, reconstruction, or 

modification after October 4, 2023. Final 

amendments to 40 CFR part 60, subpart 

Kb, are applicable to affected facilities 

that begin construction, reconstruction, 

or modification after July 23, 1984, and 

before October 4, 2023. Federal, State, 

local, and Tribal government entities 

that own and/or operate VOL storage 

vessels are affected by this action. If you 

have any questions regarding the 

applicability of this action to a 

particular entity, you should carefully 

examine the applicability criteria found 

in 40 CFR part 60, subparts Kb and Kc, 

and consult the person listed in the FOR

FURTHER INFORMATION CONTACT section of 

this preamble, your State air pollution 

control agency with delegated authority 

for NSPS, or your EPA Regional Office. 

B. Where can I get a copy of this 

document and other related 

information? 

In addition to being available in the 

docket, an electronic copy of this final 

action is available on the internet at 

https://www.epa.gov/stationary-sourcesair-pollution/volatile-organic-liquidstorage-vessels-including-petroleum. 

Following publication in the Federal 

Register, the EPA will post the Federal 

Register version of the final rule and 

key technical documents at this same 

website. 

C. Judicial Review and Administrative 

Review 

Under CAA section 307(b)(1), judicial 

review of this final action is available 

only by filing a petition for review in 

the United States Court of Appeals for 

the District of Columbia Circuit (the 

court) by December 16, 2024. Under 

CAA section 307(b)(2), the requirements 

established by this final rule may not be 

challenged separately in any civil or 

criminal proceedings brought by the 

EPA to enforce the requirements. 

Section 307(d)(7)(B) of the CAA 

further provides that ‘‘[o]nly an 

objection to a rule or procedure which 

was raised with reasonable specificity 

during the period for public comment 

(including any public hearing) may be 

raised during judicial review.’’ This 

section also provides a mechanism for 

the EPA to convene a proceeding for 

reconsideration, ‘‘[i]f the person raising 

an objection can demonstrate to the EPA 

that it was impracticable to raise such 

objection within [the period for public 

comment] or if the grounds for such 

objection arose after the period for 

public comment (but within the time 

specified for judicial review) and if such 

objection is of central relevance to the 

outcome of the rule.’’ Any person 

seeking to make such a demonstration to 

us should submit a Petition for 

Reconsideration to the Office of the 

Administrator, U.S. Environmental 

Protection Agency, Room 3000, WJC 

West Building, 1200 Pennsylvania Ave. 

NW, Washington, DC 20460, with a 

copy to both the person(s) listed in the 

preceding FOR FURTHER INFORMATION

CONTACT section and the Associate 

General Counsel for the Air and 

Radiation Law Office, Office of General 

Counsel (Mail Code 2344A), U.S. 

Environmental Protection Agency, 1200 

Pennsylvania Ave. NW, Washington, DC 

20460. 

II. Background 

A. What is the statutory authority for 

this action? 

The EPA’s authority for this final rule 

is CAA section 111, which governs the 

establishment of standards of 

performance for stationary sources. 

Section 111(b)(1)(A) of the CAA requires 

the EPA Administrator to list categories 

of stationary sources that in the 

Administrator’s judgment cause or 

contribute significantly to air pollution 

that may reasonably be anticipated to 

endanger public health or welfare. The 

EPA must then issue performance 

standards for new (and modified or 

reconstructed) sources in each source 

category pursuant to CAA section 

111(b)(1)(B). These standards are 

referred to as new source performance 

standards, or NSPS. The EPA has the 

authority to define the scope of the 

source categories, determine the 

pollutants for which standards should 

be developed, set the emission level of 

the standards, and distinguish among 

classes, types, and sizes within 

categories in establishing the standards. 

CAA section 111(b)(1)(B) requires the 

EPA to ‘‘at least every 8 years review 

and, if appropriate, revise’’ new source 

performance standards. However, the 

Administrator need not review any such 

standard if the ‘‘Administrator 

determines that such review is not 

appropriate in light of readily available 

information on the efficacy’’ of the 

standard. When conducting a review of 

an existing performance standard, the 

EPA has the discretion and authority to 

add emission limits for pollutants or 

emission sources not currently regulated 

for that source category. 

In setting or revising a performance 

standard, CAA section 111(a)(1) 

provides that performance standards are 

to reflect ‘‘the degree of emission 

limitation achievable through the 

application of the best system of 

emission reduction which (taking into 

account the cost of achieving such 

reduction and any nonair quality health 

and environmental impact and energy 

requirements) the Administrator 

determines has been adequately 

demonstrated.’’ The term ‘‘standard of 

performance’’ in CAA section 111(a)(1) 

makes clear that the EPA is to determine 

both the best system of emission 

reduction for the regulated sources in 

the source category and the degree of 

emission limitation achievable through 

application of the BSER. The EPA must 

then, under CAA section 111(b)(1)(B), 

promulgate standards of performance 

for new sources that reflect that level of 

stringency. CAA section 111(b)(5) 

generally precludes the EPA from 

prescribing a particular technological 

system that must be used to comply 

with a standard of performance. Rather, 

sources can select any measure or 

combination of measures that will 

achieve the standard. CAA section 

111(h)(1) authorizes the Administrator 

to promulgate ‘‘a design, equipment, 

work practice, or operational standard, 

or combination thereof’’ if in his or her 

judgment, ‘‘it is not feasible to prescribe 


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83298 Federal Register / Vol. 89, No. 199 / Tuesday, October 15, 2024 / Rules and Regulations 

1On October 15, 2003 (68 FR 59328), the EPA 

finalized amendments to NSPS subpart Kb to 

exempt certain storage vessels by capacity and 

vapor pressure, exempt process tanks, and add a 

process tank definition. At the same time, the EPA 

also amended the rule to exempt storage vessels 

that are subject to the National Emission Standards 

for Hazardous Air Pollutants (NESHAP) for Solvent 

Extraction of Vegetable Oil Production. 

or enforce a standard of performance.’’ 

CAA section 111(h)(2) provides the 

circumstances under which prescribing 

or enforcing a standard of performance 

is ‘‘not feasible,’’ such as when the 

pollutant cannot be emitted through a 

conveyance designed to emit or capture 

the pollutant or when there is no 

practicable measurement methodology 

for the particular class of sources. 

Pursuant to the definition of new 

source in CAA section 111(a)(2), 

standards of performance apply to 

facilities that begin construction, 

reconstruction, or modification after the 

date of publication of the proposed 

standards in the Federal Register. 

Under CAA section 111(a)(4), 

‘‘modification’’ means any physical 

change in, or change in the method of 

operation of, a stationary source that 

increases the amount of any air 

pollutant emitted by such source or 

which results in the emission of any air 

pollutant not previously emitted. 

Changes to an existing facility that do 

not result in an increase in emissions 

are not considered modifications. Under 

the provisions in 40 CFR 60.15, 

‘‘reconstruction’’ means the replacement 

of components of an existing facility 

such that: (1) the fixed capital cost of 

the new components exceeds 50 percent 

of the fixed capital cost that would be 

required to construct a comparable 

entirely new facility; and (2) it is 

technologically and economically 

feasible to meet the applicable 

standards. Pursuant to CAA section 

111(b)(1)(B), the standards of 

performance or revisions thereof shall 

become effective upon promulgation. 

B. How does the EPA perform the NSPS 

review? 

As noted in section II.A. of this 

preamble, CAA section 111 requires the 

EPA to, at least every 8 years, review 

and, if appropriate, revise the standards 

of performance applicable to new, 

modified, and reconstructed sources. If 

the EPA revises the standards of 

performance, the standards must reflect 

the degree of emission limitation 

achievable through the application of 

the BSER considering the cost of 

achieving such reduction and any 

nonair quality health and environmental 

impact and energy requirements. CAA 

section 111(a)(1). 

In reviewing an NSPS to determine 

whether it is ‘‘appropriate’’ to revise the 

standards of performance, the EPA 

evaluates the statutory factors, which 

may include consideration of the 

following information: 

• 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 that indicates 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 as a 

means of evaluating whether a given 

control achieves emission reduction at a 

reasonable cost. A cost effectiveness 

analysis allows comparisons of relative 

costs and outcomes (effects) of two or 

more options. In general, cost 

effectiveness is a measure of the 

outcomes produced by resources spent. 

In the context of air pollution control 

options, cost effectiveness typically 

refers to the annualized cost of 

implementing an air pollution control 

option divided by the amount of 

pollutant reductions realized annually. 

After the EPA evaluates the statutory 

factors, the EPA compares the various 

systems of emission reductions and 

determines which system is ‘‘best’’ and 

therefore represents the BSER. The EPA 

then establishes a standard of 

performance that reflects the degree of 

emission limitation achievable through 

the implementation of the BSER. In 

performing this analysis, the EPA can 

determine whether subcategorization is 

appropriate based on classes, types, and 

sizes of sources, and may identify a 

different BSER and establish different 

performance standards for each 

subcategory. The result of the analysis 

and the BSER determination leads to 

standards of performance that apply to 

facilities that begin construction, 

reconstruction, or modification after the 

date of publication of the proposed 

standards in the Federal Register. 

Because the NSPS reflect the BSER 

under conditions of proper operation 

and maintenance, in doing its review, 

the EPA also evaluates and determines 

the proper testing, monitoring, 

recordkeeping, and reporting 

requirements needed to ensure 

compliance with the emission 

standards. 

C. What is the source category regulated 

in this final action? 

The EPA first promulgated NSPS for 

petroleum liquid storage vessels on 

March 8, 1974 (39 FR 9317). These 

standards of performance are codified in 

40 CFR part 60, subpart K, and are 

applicable to sources that commence 

construction, modification, or 

reconstruction after June 11, 1973, and 

prior to May 19, 1978. These standards 

were amended several times before 

1980, when the EPA proposed to 

establish revised NSPS for petroleum 

liquid storage vessels as NSPS subpart 

Ka (45 FR 23379; April 4, 1980). In 

1982, the EPA published a list of 

priority sources for which additional 

NSPS should be established (47 FR 951; 

January 8, 1982), and VOL storage 

vessels at synthetic organic chemical 

manufacturers were included in the 

priority list. 

Pursuant to the EPA’s authority under 

CAA section 111, the Agency proposed 

(49 FR 29698; July 23, 1984) and 

promulgated (52 FR 11420; April 8, 

1987) NSPS for VOL storage vessels 

(including petroleum liquid storage 

vessels) for which construction, 

reconstruction, or modification 

commenced after July 23, 1984, as NSPS 

subpart Kb.1 NSPS subpart Kb regulates 

storage vessels with a capacity of 75 

cubic meters (m3) (∼20,000 gallons) or 

more that store VOLs with a maximum 

true vapor pressure (MTVP) greater than 

or equal to 15.0 kilopascals (kPa) (∼2.18 

pounds per square inch absolute (psia)) 

and from storage vessels with a capacity 

of 151 m3 (∼40,000 gallons) or more that 

store organic liquids with an MTVP 


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2All 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). 

3As part of NSPS subpart Kb, the EPA proposed 

(49 FR 29703; July 23, 1984) and finalized (52 FR 

11421; April 8, 1987) that the best demonstrated 

technology for vessels storing VOL liquids with 

vapor pressures less than 76.6 kPa (≅11.1 psia) 

consists of an IFR with a liquid-mounted or 

mechanical shoe primary seal and controlled 

fittings or an EFR with a liquid-mounted or 

mechanical shoe primary seal and gasketed fittings. 

For vessels with greater vapor pressures, the EPA 

determined the best demonstrated technology to be 

a closed vent system and control device. 

4A fixed roof storage vessel consists of a 

cylindrical steel shell with a permanently affixed 

roof, which may vary in design from cone or domeshaped to flat. 

5Numerous fittings pass through or are attached 

to floating decks to accommodate structure support 

components or to allow for operational functions. 

Typical deck fittings include, but are not limited to 

access hatches, gauge floats, gauge hatch/sample 

wells, rim vents, deck drains, deck legs, vacuum 

breakers, pontoon covers and guidepoles. IFR 

storage vessels may also have deck seams, fixed roof 

support columns, ladders, and/or stub drains. 

6For 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-factorsandquantification/ap-42-compilation-air-emissionsfactors. 

greater than or equal to 3.5 kPa (∼0.51 

psia). VOC emissions controls are 

required on storage vessels with a 

capacity of 75 m3 (∼20,000 gallons) or 

more that store VOLs with an MTVP 

greater than or equal to 27.6 kPa (∼4.0 

psia) and from storage vessels with a 

capacity of 151 m3 (∼40,000 gallons) or 

more that store organic liquids with an 

MTVP greater than or equal to 5.2 kPa 

(∼0.75 psia). NSPS subpart Kb emission 

controls include the use of an external 

floating roof (EFR), an internal floating 

roof (IFR), or a closed vent system and 

a control device (see 40 CFR 60.110b(a) 

and 40 CFR 60.112b(a) and (b)).2 3 NSPS 

subpart Kb also specifies testing, 

monitoring, recordkeeping, reporting, 

and other requirements in 40 CFR 

60.113b through 40 CFR 60.116b to 

ensure compliance with the standards. 

Storage vessels with an EFR consist of 

an open-top cylindrical steel shell 

equipped with a deck that floats on the 

surface (commonly referred to as a 

floating ‘‘roof’’) of the stored liquid. 

Storage vessels with an IFR are fixed 

roof vessels 4 that also have a deck 

internal to the vessel that floats on the 

liquid surface (commonly referred to as 

an internal floating ‘‘roof’’) within the 

fixed roof vessel. 

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 liquidmounted or mechanical shoe primary 

seal (to be used with or without a 

secondary seal), or a vapor-mounted 

primary seal in combination with a 

secondary seal. For EFRs, NSPS subpart 

Kb allows either a liquid-mounted or 

mechanical shoe primary seal, both of 

which must be used with a secondary 

seal; vapor-mounted primary seals are 

not allowed for EFRs. NSPS subpart Kb 

also requires numerous deck fittings 5

on the floating roof to be equipped with 

a gasketed cover or lid that is kept in the 

closed position at all times (i.e., no 

visible gap), except when the device 

(deck fitting) is in actual use, to prevent 

VOC emissions from escaping through 

the deck fittings. In addition, NSPS 

subpart Kb requires owners and 

operators to conduct visual inspections 

to check for defects in the floating roof, 

rim seals, and deck fittings (e.g., holes, 

tears, or other openings in the rim seal, 

or covers and lids on deck fittings that 

no longer close properly) that could 

expose the liquid surface to the 

atmosphere and potentially result in 

VOC emission losses through rim seals 

and deck fittings.6

NSPS subpart Kb includes two 

primary alternative means of 

compliance. Owners or operators may 

either comply with the consolidated air 

rule provisions for storage vessels in 40 

CFR part 65, subpart C, or comply with 

the national emission standards for 

hazardous air pollutants (NESHAP) for 

storage vessels in 40 CFR part 63, 

subpart WW (NESHAP subpart WW). 

The substantive control requirements in 

these rules are the same as in NSPS 

subpart Kb although they may have 

slight differences in the details of the 

fitting and inspection requirements. 

The EPA proposed the current review 

of the VOL storage vessels (including 

petroleum liquid storage vessels) NSPS 

subpart Kb on October 4, 2023. We 

received 29 comments from industry, 

environmental groups, State 

environmental agencies, and others 

during the comment period. After the 

conclusion of the comment period, we 

received one additional comment in 

February 2024. A summary of the more 

significant comments we received 

regarding the proposed rule and our 

responses are provided in this preamble. 

A summary of all other public 

comments on the proposal and the 

EPA’s responses to those comments is 

available in New Source Performance 

Standards for Volatile Organic Liquid 

Storage Vessels, Background 

Information for Final Amendments, 

Summary of Public Comments and 

Responses, Docket ID No. EPA–HQ– 

OAR–2023–0358. In this action, the EPA 

is finalizing decisions and revisions 

pursuant to CAA section 111(b)(1)(B) 

review for VOL storage vessels after our 

considerations of all the comments 

received. 

D. What outreach and engagement did 

the EPA conduct? 

As part of this rulemaking, the EPA 

engaged and consulted with the public, 

including communities with 

environmental justice (EJ) concerns, 

through interactions such as providing a 

webinar, offering information on the 

website for this rule, and informing the 

public of the proposed action by 

sending notifications with summaries of 

the action and information on how to 

comment. These opportunities allowed 

the EPA to hear directly from the public, 

especially communities potentially 

impacted by this final action. The 

webinar slides can be found in the 

docket for this rule (Docket ID No. EPA– 

HQ–OAR–2023–0358). 

Prior to proposal publication, the EPA 

conducted outreach by providing 

background on the source category and 

the existing requirements of NSPS 

subpart Kb on the September 19, 2023, 

EJ National Community Engagement call 

and on the August 31, 2023, National 

Tribal Air Association (NTAA) call. 

After publication, the EPA conducted a 

community outreach webinar on 

October 24, 2023, which was focused on 

discussing the details of the proposed 

rulemaking and how to provide 

comment on the proposed rule. 

Additionally, the EPA discussed the 

contents of the proposed rule on an 

October 26, 2023, NTAA call and 

encouraged interested parties to submit 

comments. The EPA received a request 

from one Tribe for consultation. On 

November 8, 2023, the EPA met with 

that Tribe for the purposes of discussing 

NSPS subpart Kc and other issues but 

was unable to conduct consultation on 

this specific rulemaking. 

III. What changes did we propose for 

the VOL Storage Vessel NSPS? 

On October 4, 2023, the EPA 

proposed the current review of the VOL 

Storage Vessel NSPS. In that action, we 

proposed the following actions under 

NSPS subpart Kc: 


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• General applicability thresholds 

that include VOL storage vessels greater 

than or equal to 20,000 gallons (gal). 

• Vapor pressure thresholds for 

controlled VOL storage vessels greater 

than or equal to 40,000 gal (151 m3) 

with MTVPs greater than or equal to 0.5 

psia (3.4 kPa). 

• Vapor pressure thresholds for 

controlled VOL storage vessels greater 

than or equal to 20,000 gal (75.7 m3) and 

less than 40,000 gal (151 m3) with 

MTVPs greater than or equal to 1.5 psia 

(10.3 kPa). 

• Improved standards of performance 

for vessels that have IFRs, EFRs, and 

closed vent systems routed to a control 

device, fuel gas system, or process 

designed to achieve an average 98 

percent control efficiency. 

• Updated standards of performance 

for IFR storage vessels that include 

improved seal system requirements, 

guidepole configurations reflective of 

the 2000 U.S. EPA Storage Tank 

Emission Reduction Partnership 

Program (STERPP), and annual lower 

explosive limit (LEL) monitoring. 

• Updated standards of performance 

for EFR storage vessels that include 

requirements for welded deck seams, 

and improved guidepole requirements. 

• Updated standards for closed vent 

systems that are routed to a control 

device, fuel gas system, or process and 

include requirements for preventing 

emissions venting to atmosphere, 

annual EPA Method 21 monitoring, and 

quarterly audible, visual, and olfactory 

(AVO) inspections. 

• Degassing standards of performance 

for VOL storage vessels greater than or 

equal to 1 million gal (3,790 m3) with 

MTVPs greater than or equal to 1.5 psia 

(10.3 kPa). 

• Modification provisions dependent 

upon an increase of the MTVP from the 

VOLs previously stored. 

• Improved testing, monitoring, and 

inspection requirements. 

• Provisions establishing that 

emission limitations apply at all times, 

including during periods of SSM. 

• Improved recordkeeping and 

reporting requirements, which include 

the implementation of electronic 

reporting. 

Additionally, we proposed to add 

electronic reporting requirements to the 

existing subpart, NSPS subpart Kb. 

IV. What actions are we finalizing and 

what is our rationale for such 

decisions? 

The EPA is finalizing revisions to the 

NSPS for VOL storage vessels pursuant 

to CAA section 111(b)(1)(B) review. The 

EPA is promulgating the NSPS revisions 

in a new subpart, 40 CFR part 60, 

subpart Kc. The new NSPS subpart is 

applicable to affected sources 

constructed, modified, or reconstructed 

after October 4, 2023. 

Under NSPS subpart Kc, we are 

finalizing standards that reflect the 

BSER for affected storage vessels. The 

rulemaking proposal included different 

criteria thresholds for general 

applicability versus for storage vessel 

control. Under the finalized general 

applicability provisions, the EPA has 

included a new exemption for storage 

vessels that only store VOL with an 

MTVP less than 0.25 psia (1.7 kPa) in 

response to comments we received 

asking to eliminate recordkeeping 

requirements for storage vessels with 

vapor pressures well below the 

thresholds for which controls are 

required. We are finalizing the capacity 

and vapor pressure thresholds for which 

controls are required as proposed. 

Specifically, we are finalizing control 

requirements for: (1) VOL storage 

vessels greater than or equal to 40,000 

gal (151 m3) with MTVPs greater than or 

equal to 0.5 psia (3.4 kPa); and (2) VOL 

storage vessels greater than or equal to 

20,000 gal (75.7 m3) and less than 

40,000 gal (151 m3) with MTVPs greater 

than or equal to 1.5 psia (10.3 kPa). We 

are also finalizing modification 

provisions similar to those proposed, 

but we are clarifying that a modification 

occurs when a ‘‘. . . storage vessel is 

used to store VOL that has a greater 

maximum true vapor pressure than all 

VOL historically stored or permitted.’’ 

In addition to updates involving 

applicability and modification, we are 

finalizing the proposed standards for 

storage vessels with IFRs, EFRs, and 

closed vent systems routed to a control 

device, fuel gas system, or process, with 

minor adjustments based on feedback. 

Regarding degassing controls, we are 

finalizing the provisions with minor 

revisions to require controls on 

nonflammable liquid degassing until 

reaching 5,000 parts per million by 

volume (ppmv) as methane vapor space 

concentration rather than the 10 percent 

LEL. 

We are finalizing testing, monitoring, 

and inspection requirements as 

proposed, with some minor revisions 

that involve matters such as the 

timelines and frequency for completing 

inspections, LEL monitoring calibration 

procedures, inspection requirements, 

and the MTVP determinations. 

Similarly, we are finalizing the 

recordkeeping and reporting 

requirements with minor revisions from 

the proposal involving matters such as 

pressure releases, closed vent system 

monitoring, and reporting deadlines. 

This action also finalizes standards of 

performance in NSPS subpart Kc that 

apply at all times including during 

periods of SSM and other changes such 

as electronic reporting, as proposed. 

This action also finalizes revisions in 

NSPS subpart Kb to require electronic 

reporting as proposed. 

A. Revised NSPS for VOL Storage 

Vessels That Commenced Construction, 

Reconstruction, or Modification After 

July 23, 1984, and on or Before October 

4, 2023 

We proposed revisions to NSPS 

subpart Kb to add electronic reporting 

requirements. We are finalizing those 

revisions as proposed. Our response to 

major comments received on the 

proposed NSPS subpart Kb revisions are 

provided in this section. Additional 

public comments received and our 

responses to those comments are 

include in the Summary of Public 

Comments and Responses document 

included in Docket ID No. EPA–HQ– 

OAR–2023–0358. 

Comment: One commenter stated that 

the EPA has no lawful or rational basis 

for not reviewing the flare standards 

from existing NSPS subpart Kb to 

consider whether to revise NSPS 

subpart Kb itself. The commenter stated 

that since the EPA has declined to 

revise the general provisions to include 

specific monitoring requirements to 

ensure compliance, the EPA must revise 

the NSPS subpart Kb provisions to do 

so, as expressly required by 40 CFR 

60.18(d). The commenter stated that the 

EPA’s failure to consider whether to 

revise the NSPS subpart Kb standards 

also violates a consent decree that the 

EPA entered into to resolve 

environmental groups’ lawsuit regarding 

the EPA’s failure to comply with its 8- 

year review obligations under CAA 

section 111(b)(1)(B) for the flare 

provisions from NSPS subpart Kb and 

other NSPS subparts, as well as its 8- 

year review obligations for certain 

NESHAP subparts. 

Response: The EPA disagrees with 

this comment. We reviewed NSPS 

subpart Kb and proposed new standards 

of performance, including new design, 

operating, and monitoring requirements 

for flares, in the new NSPS subpart Kc 

under CAA section 111(b)(1)(B), which 

requires that the EPA ‘‘. . . review and, 

if appropriate, revise such standards 

following the same procedures required 

by this subsection for promulgating 

such standards.’’ 

CAA section 111(b)(1)(B) does not 

require retroactive revisions to the 

existing NSPS subpart (i.e., NSPS 

subpart Kb). Rather, any revision to an 

NSPS must follow the same procedures 


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for promulgating such standards under 

CAA section 111(b)(1)(B). CAA section 

111 establishes a bifurcated approach to 

regulating sources. Under CAA section 

111(b)(1)(B), the EPA is required to 

promulgate standards of performance 

for new sources, which CAA section 

111(a)(2) defines as ‘‘any stationary 

source, the construction or modification 

of which is commenced after the 

publication of regulations (or, if earlier, 

proposed regulations) prescribing a 

standard of performance under this 

section which will be applicable to such 

source.’’ Existing sources are defined at 

CAA section 111(a)(6) to mean ‘‘any 

stationary source other than a new 

source’’ and are regulated via a State 

planning process pursuant to CAA 

section 111(d). Accordingly, the 

revisions, which are being finalized in 

a new NSPS subpart Kc, apply to 

sources that have commenced 

construction, reconstruction, or 

modification after October 4, 2023, the 

proposal date for this action. Sources 

presently subject to NSPS subpart Kb 

are not, by definition under this 

statutory provision, new sources that 

could be subjected to the revised 

standards finalized in NSPS subpart Kc. 

Rather, they are treated as existing 

sources relative to the revised standards 

finalized in NSPS subpart Kc. Revision 

of the flare provisions in NSPS subpart 

Kb consistent with the changes being 

finalized with respect to NSPS subpart 

Kc would be akin to directly applying 

a new standard of performance to 

existing sources, which would be 

inconsistent with the statutory structure 

that subjects regulation of new and 

existing sources to separate processes. 

Further, NSPS subpart Kc includes 

standards prescribed in accordance with 

CAA section 111(h)(1), for flares and 

other closed vent systems routed to a 

control device designed to achieve a 98 

percent reduction in VOC emissions. 

Because CAA section 111(b)(1)(B) does 

not require revisions to the existing 

NSPS subpart (i.e., NSPS subpart Kb), 

which continues to require 95 percent 

reduction in VOC emissions when using 

a flare, the EPA did not propose in this 

rulemaking to reopen NSPS subpart Kb 

to include the new operating and 

monitoring requirements for flares that 

are needed to assure 98 percent VOC 

reduction when using a flare. 

Moreover, because regulated sources 

subject to NSPS subpart Kb were not 

given notice of any such potential 

change, altering the flare requirements 

in NSPS subpart Kb in the final rule 

would unfairly put sources that have 

been using flares to comply with NSPS 

subpart Kb in violation of such 

requirements upon the effective date of 

this final rule. Thus, the EPA is not 

amending NSPS subpart Kb to reflect 

the new operating and monitoring flare 

requirements that are included in the 

new NSPS subpart Kc. The EPA notes, 

however, that as existing sources trigger 

modification, they will become subject 

to NSPS subpart Kc and the new flare 

requirements in the rule. 

We disagree with the commenter’s 

assertion that our review findings 

violate the consent decree. In that 

consent decree, the EPA agreed to 

review and, if necessary, revise NSPS 

subpart Kb. In this case, the EPA 

proposed these revisions as a new 

subpart to prevent application of ‘‘new 

source’’ standards to sources that are 

‘‘existing’’ at the time of proposal. Thus, 

our proposal of NSPS subpart Kc 

reflects our review of NSPS subpart Kb 

and the revisions to that standard 

appropriate for new sources. 

Comment: One commenter stated that 

the EPA unlawfully and arbitrarily 

failed to revise existing NSPS subpart 

Kb to specify that the SSM exemptions 

from the [40 CFR part 60] general 

provisions do not apply. The 

commenter stated that the EPA has 

acted outside its statutory authority in 

promulgating the unlawful SSM 

exemptions from the general provisions, 

and therefore the Agency must revise 

NSPS subpart Kb to make clear that the 

general provisions’ exemptions do not 

apply. The commenter noted that 

although CAA section 111(b)(1)(B) 

allows the EPA to avoid revising 

standards when ‘‘review is not 

appropriate in light of readily available 

information on the efficacy of such 

standard,’’ the EPA could not lawfully 

or rationally invoke that exception, 

since the application of the general 

provisions’ exemptions to NSPS subpart 

Kb is plainly unlawful. 

Response: As noted in the previous 

comment response, we reviewed the 

current subpart Kb standards, 

determined a series of appropriate 

revisions, and concluded that these 

revisions should be completed as a 

separate subpart. We disagree with the 

commenter that additional revision to 

NSPS subpart Kb is necessary to remove 

SSM exemptions in the 40 CFR part 60 

general provisions. First, we note that 

the performance testing requirements in 

40 CFR 60.113b(c) clearly indicate that 

the provisions in 40 CFR 60.8 do not 

apply. As such, objectionable language 

regarding performance test results 

obtained during SSM events is not 

applicable under NSPS subpart Kb. 

Second, the SSM exemption in 40 CFR 

60.11(c) is also not applicable to NSPS 

subpart Kb because NSPS subpart Kb 

does not contain opacity limits. Because 

the sections in the 40 CFR part 60 

general provisions that contain 

potentially unlawful SSM exemptions 

are not applicable under NSPS subpart 

Kb, we found no need to further revise 

NSPS subpart Kb at this time. 

B. Revised NSPS for VOL Storage 

Vessels That Commenced Construction, 

Reconstruction, or Modification After 

October 4, 2023 

This section describes the key 

technical standards that were proposed, 

the major comments received on the 

proposed requirements, our responses to 

those comments, and our rationale for 

the final requirements. Additional 

public comments received on the 

technical standards and our responses 

to those comments are included in the 

Summary of Public Comments and 

Responses document included in 

Docket ID No. EPA–HQ–OAR–2023– 

0358. 

The EPA is finalizing standards of 

performance that reflect the BSER as 

well as alternative compliance 

standards for controlled storage vessels. 

The final standards are consistent with 

the determinations explained in the 

rulemaking proposal (88 FR 68540–47; 

October 4, 2023) and the analysis 

detailed in the memorandum Control 

Options for Storage Vessels in Docket ID 

No. EPA–HQ–OAR–2023–0358. While 

the EPA has made minor adjustments to 

these standards based on public 

comment, the BSER determination 

remains unchanged. The adjustments 

incorporated based on public comment 

are detailed in sections IV.B.4. and 5. of 

this document. 

In summary, the finalized BSER 

analyses for NSPS subpart Kc are 

dependent on the MTVP of a stored 

VOL and follow the precedent 

established in NSPS subparts Kb, Ka, 

and K. In the NSPS subpart K proposal, 

the EPA detailed its justification for the 

use of equipment specification (or work 

practice) standards. As part of the 

original rulemaking proposal, the EPA 

explained that equipment specifications 

are the most practical method of 

regulating storage vessel emissions. 

Direct emission measurements for 

storage vessels are often impractical, 

and storage vessel emissions are often 

modeled and dependent on many 

distinguishing factors and variables. The 

EPA believes that equipment 

specification standards are less 

burdensome for the storage vessel 

operation and enforcement (38 FR 

15406; May 4, 1973). For VOL storage 

vessels with an MTVP less than 11.1 

psia, the EPA is finalizing the following 

BSER as proposed (88 FR 68542; 


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October 4, 2023): a fixed roof in 

conjunction with an internal floating 

roof equipped with a liquid-mounted or 

mechanical shoe primary seal and a 

continuous rim mounted secondary 

seal, either a flexible fabric sleeve or 

gasketed sliding cover on pipe columns 

(if any), specific STERPP compliant 

guidepole configurations, and gasketed 

covers. 

The EPA is also finalizing two 

alternative compliance options for VOL 

storage vessels with MTVPs less than 

11.1 psia as proposed: 

(1) An external floating roof equipped 

with a liquid-mounted or mechanical 

shoe primary seal and a continuous rimmounted secondary seal, with welded 

deck seams and both seals meeting 

certain gap requirements, specific 

guidepole configurations, and gasketed 

covers; or 

(2) A closed vent system routed to a 

98 percent effective control device, fuel 

gas system, or process. 

For VOL storage vessels with MTVPs 

greater than or equal to 11.1 psia, the 

EPA is finalizing, as proposed, the BSER 

as a closed vent system routed to a 98 

percent effective control device, fuel gas 

system, or process. 

1. Vapor Pressure Applicability 

Thresholds 

NSPS subpart Kb established control 

requirements, at 40 CFR 60.112b(a), for 

storage vessels based on vessel capacity 

and VOL vapor pressures. In our review 

of NSPS subpart Kb, we assessed the 

vapor applicability thresholds for 

affected facilities and for controls on 

affected storage vessels to determine 

whether these thresholds needed to be 

revised for purposes of NSPS subpart 

Kc. In NSPS subpart Kb there are two 

different sets of vapor pressure 

applicability thresholds: one for 

determining affected facilities and one 

for determining controls. 

We proposed to not include specific 

vapor pressure applicability thresholds 

in defining an affected facility under 

NSPS subpart Kc. As such, the proposed 

affected facility under NSPS subpart Kc 

is any storage vessel with a capacity of 

20,000 gallons or more used to store a 

VOL without exclusion for storage 

vessels under a set vapor pressure. 

Based on comments received, we are 

adding an exemption at 40 CFR 

60.110c(b)(8) for storage vessels that 

only store VOL with an MTVP of less 

than 0.25 psia. This revision from 

proposal helps to limit burden for 

storage vessels that only store VOL with 

very low vapor pressures, but it does not 

otherwise impact the control standards 

proposed for NSPS subpart Kc. 

Based on the BSER analysis, we 

proposed to revise the vapor 

applicability thresholds that require 

emission controls under NSPS subpart 

Kc. Specifically, we proposed to revise 

the MTVP threshold for smaller storage 

vessels (those with capacity of at least 

20,000 gallons but less than 40,000 

gallons) to 1.5 psia and for larger storage 

vessels (those with capacity of 40,000 

gallons or more) to 0.5 psia. We 

determined that applying controls for 

VOL at or above these thresholds 

yielded cost-effective emission 

reductions. We are finalizing these 

thresholds as proposed. 

2. Other Applicability Provisions 

NSPS subpart Kb includes several 

provisions that exempt specific groups 

of VOL storage vessels from 

applicability under the standard. We 

proposed to carry over several of these 

exemptions, such as exemptions for: 

storage vessels that operate at coke oven 

by-product plants; bulk gasoline plants; 

gasoline service stations; pressure 

vessels; vessels attached to mobile 

vehicles; certain vessels at oil and gas 

production sites prior to custody 

transfer; and vessels that store beverage 

alcohol. We proposed to remove 

exemptions under NSPS subpart Kc for 

vessels subject to the NESHAP for 

solvent extraction for vegetable oil 

production outlined in 40 CFR part 63, 

subpart GGGG, because the standards 

proposed in NSPS subpart Kc are more 

stringent than the existing NESHAP 

subpart GGGG standards. We are 

finalizing these applicability provisions 

as proposed. 

We are adding overlap provisions, 

based on comments received, to allow 

storage vessels subject to NSPS subparts 

K, Ka, or Kb, or NESHAP subpart WW 

to comply with the provisions in NSPS 

subpart Kc because the final provisions 

in NSPS subpart Kc are at least as 

stringent as those in NSPS subparts Kb, 

Ka, and K, and NESHAP subpart WW. 

These overlap provisions, which were 

not proposed, allow facilities the 

operational flexibility of simply 

complying with NSPS subpart Kc if they 

operate storage vessels covered under 

the specified existing storage vessel 

rules. 

Comment: One commenter stated that 

the EPA should add an alternative 

compliance option that complying with 

NSPS subpart Kc demonstrates 

compliance with the floating roof 

requirements in NESHAP subpart WW. 

Another commenter suggested that the 

EPA should address overlaps between 

NSPS subpart Kc and other rules 

consistent with the overlap provisions 

in NSPS subpart Kb. 

Response: There are not overlap 

provisions in NSPS subpart Kb beyond 

the alternative means of compliance in 

40 CFR 60.110b(e). The requirements in 

the rules listed in 40 CFR 60.110b(e) are 

not equivalent to the requirements in 

NSPS subpart Kc, so we removed these 

alternative means of compliance from 

NSPS subpart Kc. We agree with 

commenters that including provisions 

in NSPS subpart Kc to allow compliance 

with the provision in NSPS subpart Kc 

to be considered compliance with the 

provisions in NSPS subpart Kb or 

NESHAP subpart WW is appropriate 

because the final requirements in NSPS 

subpart Kc are at least as stringent as 

those in NSPS subpart Kb and NESHAP 

subpart WW. As such, we have added 

provisions under 40 CFR 60.110c(h) and 

40 CFR 60.110c(i) that allow owners and 

operators with storage vessels subject to 

the standards of NSPS subparts K, Ka, 

and Kb, and NESHAP subpart WW to 

choose to comply with the provisions of 

NSPS subpart Kc to demonstrate 

compliance. This will allow facilities 

that may be subject to a NESHAP that 

references NSPS subpart Kb or NESHAP 

subpart WW but also subject to NSPS 

subpart Kc to consolidate their 

recordkeeping and reporting 

requirements and comply only with 

NSPS subpart Kc. 

3. Modification Provisions 

For purposes of CAA section 111, 

modifications are defined as ‘‘. . . any 

physical change in, or change in the 

method of operation of,’’ an existing 

facility which increases the amount of 

any air pollutant (to which a standard 

applies) emitted into the atmosphere by 

that facility or which results in the 

emission of any air pollutant (to which 

a standard applies) into the atmosphere 

not previously emitted. NSPS subpart A 

further provides provisions explaining 

how a modification is identified, as well 

as defining certain exemptions to those 

general rules. In particular, 40 CFR 

60.14(e)(4) states that the ‘‘[u]se of an 

alternative fuel or raw material’’ is not 

considered a modification if the existing 

facility was designed to accommodate 

that alternative use. The EPA proposed, 

for purposes of NSPS subpart Kc, that a 

change in the liquid stored in the 

storage vessel to a VOL with a higher 

MTVP does not constitute a ‘‘use of an 

alternative fuel or raw material’’ and 

would be considered a modification 

under NSPS subpart Kc. Specifically, 

the EPA proposed that a modification 

occurs when a ‘‘storage vessel is used to 

store VOL that has a greater maximum 

true vapor pressure than the VOL 

previously stored.’’ 


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We are finalizing modification 

provisions similar to those proposed, 

but we are clarifying that a modification 

occurs when a ‘‘. . . storage vessel is 

used to store VOL that has a greater 

maximum true vapor pressure than all 

VOL historically stored or permitted.’’ 

Commenters were concerned that our 

proposed language, which referred to 

VOL ‘‘previously stored,’’ was 

ambiguous and potentially limited the 

modification assessment to the most 

recently stored VOL. We revised the text 

to ‘‘. . . historically stored or permitted 

. . . ,’’ in order to clarify our intent that 

a modification occurs when a new VOL 

is stored that has a higher MTVP than 

any of the previously stored or 

permitted VOL (and not just the most 

recently stored VOL). Finally, we are 

also clearly stating, consistent with our 

discussion in section III.G. of the 

proposal preamble, that the alternative 

fuel or raw material exemption in 40 

CFR 60.14(e)(4) does not apply to 

storage vessels under NSPS subpart Kc. 

Comment: Several commenters stated 

that the language ‘‘the VOL previously 

stored’’ in 40 CFR 60.110c(e) is unclear 

as to whether any VOL the storage 

vessel has previously stored is included, 

or just the VOL stored immediately 

prior to the change. The proposed 40 

CFR 60.110c(e) language does not clarify 

which liquids are different, or not 

different, from ‘‘the VOL previously 

stored.’’ Without clarity on these points, 

the rule language is subject to a 

significant range of interpretations, from 

any stored organic liquid being the same 

VOL, to any de minimis change in 

liquid properties being a different VOL. 

Another commenter stated that the 

phrase ‘‘the VOL previously stored’’ 

should be removed from 40 CFR 

60.110c(e). 

Several commenters requested that 

storing a VOL with a higher MTVP than 

the liquid previously stored only be 

considered a modification if storing 

such a liquid would require 

modification of a facility’s operating 

permit. One commenter further stated 

that using a facility’s operating permit to 

determine modification would place an 

unreasonable burden of proof on facility 

owners or operators. Another 

commenter stated that storage vessels 

are permitted to handle multiple 

materials, typically using a worst-case 

scenario, and changing the liquid stored 

in the storage vessel to one above the 

permitted vapor pressure threshold 

would not necessarily increase 

emissions since emissions are based on 

other parameters and conditions, such 

as changing the hourly pumping rate, 

annual throughput, or storage 

temperature. 

Two commenters noted that storage 

vessels routinely switch between storing 

materials with lower and higher vapor 

pressures at certain facilities, such as 

batch chemical plants, refineries, and 

gasoline terminals (for example, annual 

transitions between summer and winter 

gasoline). According to the commenters, 

such routine and other operational 

transitions between products do not rise 

to the level of a ‘‘modification’’ 

triggering performance standards for 

new sources under the CAA. 

Response: We agree with the 

commenters that the proposed language 

(‘‘the VOL previously stored’’) could be 

misinterpreted to refer only to the VOL 

stored immediately prior to the change, 

and that was not our intent. For 

example, if a storage vessel has been 

used to store both summer and winter 

grades of gasoline, we did not intend 

that the next switch from summer to 

winter gasoline would trigger a 

modification of the storage vessel. We 

also agree that owners and operators 

should not trigger modification for 

introducing VOLs that do not exceed the 

MTVP of all VOLs that may also exist 

in a permit. We are clarifying the 

regulatory language to match our intent 

at proposal and reduce burden by 

replacing the phrase ‘‘the VOL 

previously stored’’ with the phrase ‘‘all 

VOL historically stored or permitted.’’ 

In discussions with industry 

representatives and the EPA permit 

specialists, we found that specific VOLs 

are not always listed in permits. 

Therefore, we are not including 

revisions suggested by some 

commenters to limit modification to 

only those actions that would require 

modification of a facility’s operating 

permit. 

We disagree with the commenters 

who suggested that changing the 

volatility of the liquids stored does not 

increase emissions from the storage 

vessel. We note that the emission rate 

for modification is expressed in 

kilograms per hour (kg/hr) and that it is 

not evaluated on an annual basis. Even 

if the facility intends to lower the fill 

rate to limit increases in annual 

emissions, the storage vessel will still 

have higher emissions (in kg/hr) during 

periods when the storage vessel is not 

being filled. 

Comment: Several commenters 

disagreed with the EPA’s proposal that 

a change in the liquid stored in the 

storage vessel to a VOL with a higher 

MTVP does not constitute a ‘‘use of an 

alternative fuel or raw material’’ and 

thus would instead be considered a 

change in the method of operation of a 

source. According to the commenters, 

the stored materials are fuels or raw 

materials for some customer or 

downstream user, and there is no 

requirement for a material to be used at 

the facility where it is being stored for 

it to be considered a raw material or a 

fuel. According to one commenter, the 

EPA had determined that changing a 

liquid, regardless of volatility, is not an 

operational change, and another 

commenter stated that storage vessel 

service changes are the kind of event 

that the EPA intended to address in 40 

CFR 60.14(e)(4). Other commenters 

recommended that the EPA retain its 

long-held interpretation that a change of 

liquids in an existing VOL storage vessel 

does not constitute a ‘‘modification’’ 

triggering applicability of NSPS subpart 

Kc. Commenters also noted that the 

proposed interpretation would 

arbitrarily apply NSPS subpart Kc to 

some storage vessels, and not to other 

identical vessels, based on their historic 

use rather than their design capabilities. 

One commenter stated that changing 

a liquid in a storage vessel is not a 

modification if the material could have 

been previously accommodated without 

a physical change or a capital 

expenditure. Some commenters 

requested that the EPA revise proposed 

40 CFR 60.110c(e) to clearly state that 

changing the material stored is not a 

modification if the storage vessel could 

accommodate the new material without 

a physical change or significant capital 

expenditure. Commenters requested that 

the EPA review historical documents 

related to NSPS subpart Kb and 

reconfirm these long-held policies 

regarding modification of storage 

vessels. 

One commenter stated that the EPA’s 

reference to FCC v. Fox Television 

Stations, Inc. for the proposition that it 

need only articulate a ‘‘good reason’’ for 

its ‘‘change in policy’’ is misplaced. 

According to the commenter, the EPA is 

not proposing to amend any of its 

existing regulations setting forth its 

policy for NSPS triggering 

‘‘modifications.’’ Rather, the proposal 

reflects a reversal of the EPA’s 

longstanding interpretation of the CAA 

and its regulations in 40 CFR 60.2 and 

60.14. Unlike a change in policy, the 

commenter contends, ‘‘an agency’s 

interpretation of a statute or regulation 

that conflicts with a prior interpretation 

is entitled to considerably less deference 

than a consistently held agency view.’’ 

Advanced Energy United, Inc. v. FERC 

(82 F.4th 1095, 1114 (D.C. Cir. 2023) 

(quoting Thomas Jefferson University v. 

Shalala, 512 U.S. 504 (1994)). 

Accordingly, it is the EPA’s long-held 

interpretation of ‘‘modifications’’—for 

nearly 40 years—that is entitled to 

deference. The commenter asserts that 


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this is particularly true where, as here, 

the EPA has not provided a justification 

for the conflicting interpretation or 

articulated the scope of changes in 

volatility of stored liquids that would 

actually trigger a ‘‘modification.’’ 

Response: The EPA disagrees with 

these comments. First, the EPA’s 

reliance on FCC v. Fox, 556 U.S. 502 

(2009), the controlling case on changes 

in agency policy, is appropriate here. 

The quote that commenters cite above, 

asserting that an agency’s statutory 

interpretation which conflicts with a 

prior interpretation is ‘‘entitled to 

considerably less deference than a 

consistently held view,’’ is from 

Thomas Jefferson University v. Shalala, 

512 U.S. 504 (1994), a 1994 Supreme 

Court case whose precedent on changes 

in agency policy was displaced by FCC 

v. Fox, in 2009, 556 U.S. 502. Under 

FCC v. Fox, ‘‘it suffices that the new 

policy is permissible under the statute, 

that there are good reasons for it, and 

that the agency believes it to be better, 

which the conscious change of course 

adequately indicates.’’ Id. at 515. 

According to the commenters, 

anything stored in a storage vessel 

should be considered an alternative fuel 

or raw material and therefore any 

change in the liquid stored should be 

exempt from being considered a 

modification. We find in this final rule 

that this interpretation of the alternative 

fuel or raw material exemption as 

applied to storage vessels is 

inappropriate and often excludes 

changes in the stored VOL that increase 

emissions and that therefore should 

trigger additional control requirements. 

The EPA explained its rationale for 

including additional modification 

provisions in section III.G. of the 

proposal preamble (88 FR 68543; 

October 4, 2023). The EPA explained 

that for purposes of NSPS subpart Kc, a 

change in the liquid stored in the 

storage vessel to an organic liquid with 

a greater MTVP does not constitute a 

‘‘use of an alternative fuel or raw 

material’’ and would be considered a 

change in the method of operation of the 

storage vessel. The primary function of 

this affected facility is the storage of 

materials. The VOLs stored in the 

storage vessel are neither raw material 

nor fuel inputs to a process at the 

affected facility itself. Furthermore, 

even had the EPA not revisited its 

interpretation regarding the application 

of 40 CFR 60.14(e)(4), we maintain that 

changing the VOL stored to one with a 

higher MTVP is a modification (a 

change in the method of operation that 

results in an increase in the emissions 

rate). The NSPS subpart Kc modification 

provisions result in meaningful 

emission reductions. For these reasons, 

the final rulemaking appropriately 

supersedes the general provisions. As 

such, the EPA is finalizing modification 

provisions such that a change in the 

liquid stored, which results in increased 

VOC emissions, would be a 

modification under NSPS subpart Kc 

and is clarifying in 40 CFR 60.110c(e) 

that, for the purposes of this source 

category, the exemption at 40 CFR 

60.14(e)(4) does not apply. 

The precedent of MTVP dependent 

standards of performance for VOL 

storage vessels was established as part 

of NSPS subpart K and has informed the 

establishment of standards for 

subsequent rulemakings under NSPS 

subparts Ka and Kb. Under these 

standards, a VOL’s MTVP (along with a 

vessel’s capacity) has served as a 

primary mechanism for determining 

suitable standards for control. The 

amended modification provisions will 

provide meaningful emission reductions 

from storage vessels that would 

otherwise go unregulated despite 

satisfying the statutory criteria for a 

modification under CAA section 

111(a)(4), as explained in this section 

and at III.G. of the proposal preamble 

(88 FR 68543; October 4, 2023). The 

modification provision, as amended, 

effectively curtails a previously existing 

loophole which had allowed owners 

and operators to circumvent the 

standards in NSPS subpart Kb. For 

example, prior to this rulemaking, an 

uncontrolled fixed roof vessel could be 

constructed and be exempt from NSPS 

subpart Kb standards because it was 

storing a low vapor pressure VOL. The 

vessel could then change operation to 

introduce a new material with a higher 

vapor pressure that would otherwise be 

subject to the NSPS had it been stored 

in the tank at the time of construction, 

but the owner or operator could 

continue to operate without meeting the 

floating roof or closed vent system and 

control device standards even if the 

vessel was constructed after the Kb 

applicability date. Similarly, if an owner 

or operator built floating roof tanks for 

VOLs with less than 11.1 psia and later 

replaced the liquid stored with a liquid 

with a vapor pressure greater than 11.1 

psia, they could thereby circumvent the 

closed vent system and control device 

requirements under 40 CFR 60.112b 

which are directly dependent on the 

MTVP of the stored VOL and which 

would otherwise apply. As such, the 

prior NSPS provided significant leeway 

for owners and operators to circumvent 

the regulations intended to control 

storage vessel emissions. To address this 

concern, the EPA is finalizing 

modification provisions such that the 

MTVP can be used as an indicator to 

determine that a change in the liquid 

stored, which results in increased VOC 

emissions, would be a modification 

under NSPS subpart Kc. 

The EPA’s decision to consider a 

change in the liquid historically stored 

or permitted to one with a higher vapor 

pressure to be a modification is 

consistent with both the statutory and 

regulatory definitions of those terms. 

CAA section 111(a) defines modification 

to mean, ‘‘any physical change in, or 

change in the method of operation of, a 

stationary source which increases the 

amount of any air pollutant emitted by 

such source or which results in the 

emission of any air pollutant not 

previously emitted.’’ Similarly, the 

General Provisions to 40 CFR part 60 

define modification at 40 CFR 60.2 to 

mean, ‘‘any physical change in, or 

change in the method of operation of, an 

existing facility which increases the 

amount of any air pollutant (to which a 

standard applies) emitted into the 

atmosphere by that facility or which 

results in the emission of any air 

pollutant (to which a standard applies) 

into the atmosphere not previously 

emitted.’’ And 40 CFR 60.14 provides a 

more detailed framework for evaluating 

modifications, which similarly states at 

paragraph (a) that: ‘‘Except as provided 

under paragraphs (e) and (f) of this 

section, any physical or operational 

change to an existing facility which 

results in an increase in the emission 

rate to the atmosphere of any pollutant 

to which a standard applies shall be 

considered a modification within the 

meaning of section 111 of the Act.’’ 

Thus, the CAA and general provisions 

for 40 CFR part 60 all rely on the same 

basic two-step process: (1) a physical 

change in, or change in the method of 

operation of, a stationary source; and (2) 

a resulting increase in emissions. 

Notably, it is not necessary for there to 

be a physical change at the source in the 

first step if there is a change in the 

method of operation. One or the other 

will suffice. We address each of these 

criteria in turn. 

First, as proposed, the EPA has 

determined that a change in the liquid 

stored in a storage vessel constitutes a 

change in the method of operation of a 

storage vessel. The primary function of 

this affected facility is the storage of 

materials, and so the only logical 

‘‘change in the method of operation’’ 

that a storage vessel would undergo is 

a change in the material stored. In other 

words, whenever a storage vessel 

changes the VOL that is stored, that is 

a change in that facility’s method of 

operation. The EPA’s interpretation 


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7See, e.g., U.S. EPA Applicability Determination 

Index, Control Number: 0400015, (referencing 40 

CFR 60.14(e)(4)–(5)) and NSPS subpart Kb 

Background Information Document (Docket ID No. 

EPA–HQ–OAR–2023–0358–0012). 

8This is bolstered when considering the other 

exemptions in 40 CFR 60.14(e): a ‘‘replacement’’ 

referred to in (e)(1) and the addition of a system or 

device referred to in (e)(5) is a physical change to 

a facility, and an increase in production rate or an 

increase in hours of operation referred to in (e)(2) 

or (3) is a change in the facility’s operation. 

However, the EPA had a rational basis for 

exempting these particular physical or operational 

changes, as a general matter, from the broader 

definition of modification under the regulations. 

regarding what constitutes a change in 

the ‘‘method of operation’’ for storage 

vessels has not changed with this 

rulemaking. In explaining the 

applicability of modification under the 

CAA, in the NSPS subpart Kb preamble, 

the EPA affirmed, ‘‘Few, if any, changes 

in the physical configuration of the 

storage vessels that would increase 

emissions are anticipated. An 

operational change that would increase 

emissions is a changing of the stored 

liquid from a VOC non-emitting liquid 

to a VOC emitting liquid’’ (49 FR 29707; 

July 23, 1984). Thus, the EPA has long 

considered the changing of the stored 

liquid to meet the statutory 

requirements for an operational change. 

Second, the changing of the stored 

liquid can lead to an increase of 

emissions whenever the MTVP of the 

new liquid is greater than the previously 

stored liquid. Thus, both statutory 

criteria for identifying a modification 

are met. 

The EPA agrees that we have 

historically applied the regulatory 

exemption under 60.14(e) for ‘‘use of an 

alternative fuel or raw material’’ to 

storage vessels. In making our decision 

regarding modifications, we reviewed 

several documents 7 and questioned 

both industry and enforcement 

personnel to better understand what 

changes are currently considered 

modifications. In the NSPS subpart Kb 

preamble, the EPA explained, ‘‘Section 

60.14(e) of the General Provisions to 

Part 60 lists several changes that are not 

considered modifications. Among these 

is the use of raw material, if prior to the 

date of proposal of the standard, the 

existing facility was designed to 

accommodate that alternative use’’ (49 

FR 29707; July 23, 1984). However, the 

EPA did not provide any further 

explanation at that time as to why the 

Agency believed this exemption applied 

to this affected facility, and the Agency 

has reconsidered the application of that 

exemption for purposes of NSPS subpart 

Kc. As explained in section III.G. of the 

proposal preamble, when the affected 

source is a storage vessel and not a 

process unit, we no longer consider a 

change in the liquid stored in the 

storage vessel (to an organic liquid with 

a higher MTVP) to qualify as a ‘‘use of 

an alternative fuel or raw material.’’ As 

discussed above, the primary function 

of an affected facility in this source 

category is the storage of materials, and 

the VOL stored in the vessel are neither 

raw material nor alternative fuel inputs 

to a process at the facility itself. While 

the storage vessel may store liquids that 

are used as an alternative fuel or raw 

material used for inputs to a process for 

another facility, it is not reasonable to 

extend application of the exemption to 

mere storage of the alternative fuel or 

raw material. Accordingly, we no longer 

believe that the exemption should be 

applied to these factual circumstances 

by the terms of the regulation. 

The EPA notes that, the fact that 40 

CFR 60.14(e) is framed as exempting 

certain activities from the definition of 

modification indicates that, absent these 

exemptions, the EPA would consider 

the exempted activity to meet the 

statutory definition of modification in 

CAA section 111(a)(4). In other words, 

the EPA created a specific provision 

exempting the ‘‘use of an alternative 

fuel or raw material’’ from the 

regulatory definition of modification 

because this activity would, as the EPA 

proposed, typically be considered an 

operational change,8 a consideration 

reinforced by the EPA’s discussion on 

modification in the NSPS subpart Kb 

preamble. In this rulemaking, the EPA 

confirms that it does not consider a 

change in the liquid stored to one with 

a higher MTVP to qualify under this 

exemption. Moreover, irrespective of 

this determination, the EPA is also 

finalizing in this rulemaking that the 

exemption in 40 CFR 60.14(e)(4) 

regarding alternative fuel or raw 

material does not apply to storage 

vessels. 

While we have determined for 

purposes of NSPS subpart Kc that a 

change in the liquid stored to a liquid 

with a higher vapor pressure does not 

constitute the ‘‘use of an alternative fuel 

or raw material,’’ we note that even if 

this exemption would otherwise apply 

by its terms, this rulemaking supersedes 

the exemption pursuant to 40 CFR 

60.14(f), because, as explained earlier, 

we have concluded that it is the better 

policy and consistent with the statutory 

definition of modification based on the 

facts of how this affected facility 

operates. The EPA has always 

maintained that there are some sources 

for which the basic exemptions from the 

standard definition of a modification 

may not be appropriate, and 40 CFR 

60.14(f) was included in the general 

provisions to afford the EPA the ability 

to supersede the general modification 

regulations, the exemption provisions in 

40 CFR 60.14(e), for those sources for 

which these provisions should not 

reasonably be applied. The EPA has 

previously applied specialized 

interpretations of modification for other 

source categories. For example, in NSPS 

subpart Ja, we included special 

provisions for the modification of flares 

at petroleum refineries because the basic 

considerations under 40 CFR 60.14(e), 

were generally developed considering 

process unit emission sources. The 

intermittent operation of a flare makes 

it difficult to use the criteria of 40 CFR 

60.14(e) to determine when a flare is 

modified (73 FR 35843; June 24, 2008). 

In our review of NSPS subpart Kb, we 

identified similar short-comings 

regarding the ‘‘process unit-oriented’’ 

modification exemptions as previously 

applied to storage vessels. The 

specialized modification provision for 

storage vessels is consistent with the 

CAA statutory requirements, the general 

definition of modification outlined in 40 

CFR 60.2 and 60.14, and previous 

determinations that source-specific 

modification provisions are justified for 

certain source categories. Accordingly, 

in this rulemaking, the EPA confirms 

that it does not consider a change in the 

liquid stored to one with a higher MTVP 

to qualify under the exemption in 40 

CFR 60.14(e)(4), and, as a matter of 

clarity, irrespective of this 

determination, this rulemaking is 

superseding the exemption. 

With respect to the comment that the 

proposed definition of modification 

would arbitrarily apply differently for 

identical vessels based on their historic 

use rather than their design capabilities, 

we disagree. As stated above, the 

modification provisions are directly 

dependent on the MTVP of the stored 

VOL. The precedent of MTVP 

dependent standards of performance for 

VOL storage vessels was established as 

part of NSPS subpart K and has 

informed the establishment of standards 

for subsequent rulemakings under NSPS 

subparts Ka and Kb. We are finalizing 

that storing a VOL with a greater MTVP 

than historically stored or permitted is 

a modification. We determined the 

BSER and set standards of performance 

considering existing emission controls 

of modified storage vessels. 

The EPA also disagrees with the 

comment advocating a requirement for 

capital expenditure to determine 

whether there is a modification and that 

a capital expenditure clause should be 

added to the language proposed at 40 

CFR 110c(e). First, we note that the 


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statute at CAA section 111(a)(4) 

contains no such requirement and the 

general provisions at 40 CFR 60.14(e)(2) 

only consider whether a capital 

expenditure is needed when 

considering an exemption from the 

definition of modification tied to 

increase in production at the facility. 

Critically, neither the statute nor the 

general provisions provide that the 

determination of whether a modification 

has occurred must be based on a capital 

expenditure. Thus, the commenters seek 

to impose an additional requirement 

that is not plainly necessary under the 

statute nor anticipated, either by 

Congress or by the EPA, without an 

explanation as to why that would be 

justified for this source category. In 

many cases, a capital expenditure is not 

needed to change the liquid stored in a 

fixed roof tank. Under the commenter’s 

proposed capital expenditure paradigm, 

an operator of a fixed roof tank used to 

store a low volatility fluid could change 

to a higher vapor pressure fluid and 

argue that no modification occurred 

even though the storage vessel has 

changed its method of operation. This 

would permit the resulting emissions 

increases without the requisite control 

that the statute would otherwise 

anticipate under such circumstances. It 

is more consistent with the statutory 

standard to consider the change in the 

liquid stored or permitted as a change 

in the method of operation and then 

assess whether an increase in the vapor 

pressure of the liquid stored triggers the 

need for controls (which would require 

a capital expenditure). We found the 

controls required under proposed NSPS 

subpart Kc are cost effective and meet 

the BSER criteria, and we see no reason 

to allow uncontrolled modified storage 

vessels or less stringent controls simply 

because the tank was initially permitted 

for or stored a less volatile liquid. 

4. Control Standards for IFRs and EFRs 

The EPA proposed standards of 

performance that reflect the BSER for 

IFRs as well as alternative compliance 

standards for controlled storage vessel 

EFRs. The EPA proposed a work 

practice standard that would require 

new IFR storage vessels be constructed 

with either a liquid-mounted or a 

mechanical shoe primary seal, a rimmounted secondary seal, and fittings on 

the floating roof that meet certain 

control requirements (e.g., gasketed 

covers, specific guidepole control 

configurations) mostly consistent with 

the requirements of fitting controls in 

NSPS subpart Kb. The EPA also 

proposed that new EFR storage vessels 

be constructed with either a liquidmounted or a mechanical shoe primary 

seal, a rim-mounted secondary seal, 

welded deck seams, and fittings on the 

floating roof that meet certain control 

requirements (e.g., gasketed covers, 

specific guidepole control 

configurations). Except for the 

guidepole controls, the fitting controls 

are mostly consistent with the 

requirements of fitting controls in NSPS 

subpart Kb. 

We are finalizing the control 

requirements for IFRs and EFRs as 

proposed with minor editorial revisions 

(such as replacing ‘‘roof leg supports’’ 

with ‘‘roof supports,’’ replacing 

‘‘bolted’’ with ‘‘bolted or otherwise 

mechanically secured,’’ and using 

consistent language regarding 

requirements for vacuum breaker/ 

automatic bleeder vents). For EFRs, we 

are also adding provisions for 

emergency roof drains to be provided 

with a slotted membrane fabric cover 

that covers at least 90 percent of the area 

of the opening. As noted by 

commenters, this provision is included 

in NSPS subpart Kb and the IFR drain 

requirements were inadvertently copied 

for EFRs in the proposed rule for NSPS 

subpart Kc. 

Comment: One commenter stated the 

proposed NSPS subpart Kc language 

refers to the floating roof being 

supported by legs when the floating roof 

is landed, but a common design for IFRs 

involves suspending the IFR from the 

fixed roof of the tank via cables. The 

commenter stated that proposed 

language at 40 CFR 60.112c(b)(1) and (4) 

should be revised to accommodate the 

cable-suspended design alternative. 

Similarly, a commenter recommended 

the EPA revise the definition of the term 

‘‘Vacuum breaker/Automatic bleeder 

vent’’ to avoid restricting vacuum 

breakers to the leg-actuated type. 

Another commenter noted that since leg 

operated vacuum breakers must contact 

the floor prior to the roof support legs, 

the EPA should consider setting a 

maximum opening distance or clarify 

that the roof is considered landed when 

the vacuum breaker leg lands. One 

commenter noted that 40 CFR 

60.112c(b)(1) reads ‘‘. . . and during 

those intervals when the storage vessel 

is completely emptied or subsequently 

emptied and refilled’’ whereas 40 CFR 

60.112c(c)(1) reads: ‘‘. . . and when the 

storage vessel is completely emptied 

and subsequently refilled.’’ The 

commenter suggested that the 

requirements for EFRs in 40 CFR 

60.112c(c)(1) be revised to be consistent 

with 40 CFR 60.112c(b)(1). 

Response: We agree with the 

commenters that the language regarding 

roof legs and vacuum breaker/automatic 

bleeder vents should be generalized to 

allow roof supports other than roof legs 

and vacuum actuations other than leg 

actuated devices and that consistent 

language should be used for EFRs. 

While we understand cable suspended 

roofs are specific to IFRs, we 

generalized the language for EFRs in the 

event different supports are developed 

for EFRs and to make the language 

consistent between 40 CFR 60.112c(b) 

and (c). We also revised the use of the 

term ‘‘vacuum breaker’’ by replacing it 

with ‘‘vacuum breaker/automatic 

bleeder vent’’ because that is the 

defined term for these devices on a 

floating roof and to distinguish these 

from vacuum breaking devices on a 

fixed roof. We are also adding a 

sentence to the roof landing monitoring 

requirements at 40 CFR 60.113c(a)(5) 

and (b)(8) to clarify that the roof is 

considered landed when the floating 

roof first rests on supports or when the 

vacuum breaker/automatic bleeder vent 

begins to open, whichever is first. This 

clarifies that the landing alarm must be 

set at the height the leg-actuated 

vacuum breaker/automatic bleeder vent 

begins to open the vent, which will be 

prior to the floating roof resting on the 

roof supports. 

Comment: One commenter stated that 

the proposed NSPS subpart Kc does not 

address the emergency roof drains that 

are utilized with certain EFRs. The 

commenter noted that NSPS subpart Kc 

specifies that ‘‘stub drains’’ are not 

required to be covered at all, which 

could be understood as exempting EFR 

emergency roof drains from control. The 

commenter recommended that the EPA 

clarify, consistent with NSPS subpart 

Kb at 40 CFR 60.112(b)(2)(ii), that each 

emergency roof drain is to be provided 

with a slotted membrane fabric cover 

that covers at least 90 percent of the area 

of the opening. 

Response: We agree with the 

commenter that we inadvertently used 

the language allowing uncontrolled stub 

drains for IFRs in the proposed EFR 

requirements. We had intended to 

maintain consistency with the EFR 

drain requirements in NSPS subpart Kb. 

We agree with the commenter that the 

reference to stub drains for EFRs is not 

appropriate as stub drains are not used 

for EFRs. In the final rule, we are 

including the requirements to use a 

slotted membrane fabric cover that 

covers at least 90 percent of the area of 

the opening at 40 CFR 60.112c(c)(2)(viii) 

consistent with the requirements for 

EFR drains in NSPS subpart Kb, as 

suggested by the commenter. 


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5. Control Standards for Closed Vent 

Systems Routed to a Control Device, 

Fuel Gas System, or Process 

For storage vessels with closed vent 

systems routed to a control device, fuel 

gas system, or process, the EPA 

proposed certain design requirements 

for the storage vessel to prevent pressure 

releases from the storage vessel and 

proposed that control devices must meet 

98 percent or greater emission reduction 

efficiency. The EPA proposed that nonflare thermal combustion devices must 

conduct performance tests initially and 

at least once every 60 months, in which 

they establish a temperature operating 

limit to which they must comply at all 

times. For flares, the EPA proposed that 

flares must meet the operating and 

monitoring requirements consistent 

with the requirements in the Refinery 

NESHAP (40 CFR 63.670 and 63.671). 

We are finalizing requirements for 

closed vent systems routed to a control 

device, fuel gas system, or process with 

some revisions from proposal for 

reasons noted in the following 

comments and responses. 

First, we are revising the vacuum 

pressure at which vacuum breaking 

devices must close from ¥0.1 pounds 

per square inch gauge (psig) to ¥0.1 

inches of water (¥0.0036 psig) to better 

reflect common storage vessel design 

requirements. We are also clarifying the 

language since a higher vacuum setting 

would be a lower absolute pressure and 

the proposed language was potentially 

ambiguous. The revised provision 

clarifies that any vacuum breaking 

device on the storage vessel must close 

while the storage vessel is still under 

vacuum of at least ¥0.1 inches of water 

(¥0.0036 psig or ¥0.025 kPa gauge). 

We proposed that storage vessels that 

are vented to a closed vent system must 

be designed to operate at elevated 

pressures (1 psig above MTVP plus any 

back pressure from the control device) 

without venting to the atmosphere. We 

are retaining this as an option but are 

adding an option to design and operate 

the recovery system to prevent venting 

from the storage vessel. In either case, 

we are retaining requirements consistent 

with those proposed that monitoring 

systems must be installed to detect 

pressure releases from each pressure 

relief device (PRD) or vacuum breaking 

device on a storage vessel and each PRD 

on the closed vent system. For owner 

and operators electing to design the 

storage vessel and closed vent system to 

operate at elevated pressures, we are 

including provisions that allow the 

control device to be taken out of service 

for maintenance provided that the 

storage vessels are operated with no 

emissions to the atmosphere. 

We are retaining requirements for 

control devices to meet 98 percent 

control efficiencies as proposed. We 

allow enclosed combustion devices to 

demonstrate on-going compliance with 

the 98 percent control efficiency using 

temperature operating limit, as 

proposed. However, we are also 

finalizing an alternative for enclosed 

combustion devices, if elected, to 

comply with the flare operating limits, 

consistent with recent provisions 

provided for gasoline distribution 

facilities (40 CFR part 60, subpart XXa 

and 40 CFR part 63, subparts R and 

BBBBBB). Lastly, we are amending the 

requirements for open-ended lines to 

align with provisions more closely 

under the Miscellaneous Organic 

Chemical Manufacturing NESHAP 

(MON). 

Comment: Two commenters suggested 

that the pressure constraints on design 

operating pressure and vacuum breaking 

devices are not technically feasible and 

could result in significant damage or 

failures of the storage vessels, stating 

that a gauge pressure higher than the 

designed pressure of the storage vessel 

or a vacuum greater than the design 

requirements could result in 

catastrophic failure of the storage vessel. 

The commenters noted that the 

proposed requirements conflict with 

American Petroleum Institute (API) 

Codes 650 and 2000. The commenters 

recommended the EPA delete the 

specific pressure requirements proposed 

and replace with general language that 

atmospheric vents should be designed 

to remain closed during normal 

operation. 

Response: In the proposal, we 

intended to require the use of lowpressure storage vessels rather than 

atmospheric storage vessels so that the 

storage vessels would be built to 

withstand higher pressures. However, 

we recognize that this may be a more 

significant retrofit for modified storage 

vessels with gas collection systems 

designed to operate at lower pressures 

such that the pressure in the storage 

vessels can remain near atmospheric 

pressure. However, if the vapor recovery 

compressor or fan fails or is shut down 

for any reason, then the storage vessel 

would vent rather than being able to 

withstand the buildup of pressure as the 

headspace in the storage vessel reaches 

saturation without venting to the 

atmosphere like a low-pressure storage 

vessel would. We are maintaining the 

positive pressure requirements as one 

compliance option, but we are also 

finalizing an option for facilities to 

design and operate a vapor recovery 

system in a manner to prevent 

atmospheric releases from the storage 

vessel. As proposed, any pressure 

release from the storage vessel is a 

deviation of the storage vessel and 

closed vent system requirements. We 

are finalizing monitoring system 

requirements for the pressure relief 

devices and vacuum breaking devices to 

identify these deviations. 

With respect to the vacuum 

requirements, we reviewed the API 650 

standards applicable to low-pressure 

storage vessels and found in section 

5.10.5.2 that these storage vessels ‘‘. . . 

may be safely subjected to a partial 

vacuum in the gas or vapor space not 

exceeding 1 ounce per square inch with 

the operating liquid level in the tank at 

any stage from full to empty.’’ One 

ounce per square inch is equivalent to 

0.0625 psi or 2 inches of water, so we 

agree that the vacuum requirement 

proposed is beyond standard design 

requirements for low-pressure storage 

vessels. We also confirmed that the API 

650 standard indicates that the 

maximum vacuum for atmospheric 

storage vessels (without needing 

additional design considerations) is 

¥0.25 kPa (or ¥1 inch of water or 

¥0.036 psig). In our proposal, we 

wanted to ensure that the vacuum vent 

is closed while there is still a slight 

vacuum in the storage vessel, to prevent 

venting to the atmosphere from the 

vacuum breaking device as the pressure 

in the storage vessel increases. In 

reviewing the storage vessel 

specifications, we determined that the 

value we proposed was higher than 

needed to achieve this objective. The 

vacuum breaking devices must open 

before the maximum vacuum pressure is 

reached, so typical opening pressures 

are 0.5 inches of water pressure. 

Therefore, we are finalizing that the 

vacuum breaking device must close 

while the storage vessel is still under 

vacuum of at least ¥0.1 inches of water 

(¥0.0036 psig or ¥0.025 kPa gauge) 

and are finalizing that a pressure release 

(deviation) occurs when the vessel 

reaches atmospheric pressure and the 

vacuum breaking device remains open. 

We are providing separate paragraphs 

for the monitoring requirements for 

PRDs between storage vessels and 

closed vent systems and adding 

monitoring requirements for the vacuum 

breaking devices on the storage vessels. 

Otherwise, the separate pressure release 

monitoring requirements we are 

finalizing in 40 CFR 60.112c(d)(1)(iii) 

and (d)(2)(iii) are the same as proposed 

for ‘‘each pressure relief device on a 

storage vessel or in a closed vent 

system,’’ in 40 CFR 60.112c(d)(2)(iii). 


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Comment: One commenter 

recommended that the EPA add a 240- 

hour planned routine maintenance 

provision for storage vessels equipped 

with a closed vent system routed to a 

control device to NSPS subparts Kb and 

Kc similar to the language in the part 63 

NESHAP regulations such as the MON 

and Organic Liquids Distribution (nongasoline) NESHAP. According to the 

commenter, if the EPA decides to retain 

the language in 40 CFR 60.110c(g) 

removing the SSM provisions, it is 

reasonable for the EPA to include a 

separate 240-hour planned routine 

maintenance provision for control 

devices in NSPS subpart Kc similar to 

the language in the MON (40 CFR 

63.2470(d)) and the associated 

recordkeeping and reporting 

requirement similar to the language in 

40 CFR 63.998(d)(2) and 63.999(c)(4). 

Response: We disagree that we should 

provide 240 hours for uncontrolled 

emissions when using an add-on control 

device. Similar provisions are not 

needed or appropriate for IFRs, which 

were determined to be the BSER for 

storage vessels storing VOLs with an 

MTVP less than 11.1 psia. We maintain 

that a 98 percent control requirement at 

all times is necessary for add-on control 

devices to achieve emission reductions 

equivalent to those for IFRs. Even for 

storage vessels storing VOLs with an 

MTVP of 11.1 psia or higher, we 

maintain that a 98 percent control 

requirement is the BSER, and that level 

of control cannot be achieved if we 

allow 240 hours of uncontrolled 

emissions. Nonetheless, if the storage 

vessel is designed to be able to operate 

at pressures above the MTVP consistent 

with the storage vessel design pressure 

requirements proposed (and being 

finalized as one compliance option), 

then the control device can be isolated 

from the storage vessel, and the closed 

vent system and the storage vessel can 

remain in service without venting to the 

atmosphere provided that the storage 

vessel is not filled to the extent that the 

pressure limits of the pressure relief 

valves on the storage vessel and closed 

vent system are exceeded and there is a 

pressure release. If there is no pressure 

release from the storage vessel during 

the planned maintenance activity, we 

agree that planned maintenance can be 

allowed. Therefore, we are including 

provisions at 40 CFR 60.112c(d)(7) to 

allow owners or operators to conduct 

planned maintenance on control devices 

while storage vessel affected facilities 

are still storing VOL under specific 

circumstances. Specifically, the storage 

vessel(s) storing VOL must be designed 

to operate above the MTVP of the stored 

VOL according to the requirements in 

40 CFR 60.112c(d)(1)(i) and must 

comply with the pressure release 

monitoring, recordkeeping, and 

reporting requirements. Eliminating 

pressure releases during the 

maintenance periods may require 

operators to limit VOL addition to the 

storage vessel (such as only adding VOL 

when there is also corresponding 

withdrawal of VOL from the storage 

vessel), but the operator is expected to 

operate the storage vessel without a 

pressure release or atmospheric venting 

during the maintenance period. 

Comment: One commenter stated that 

the EPA should define ‘‘vapor 

combustion unit’’ separately from 

‘‘incinerator’’ and apply appropriate 

monitoring provisions to vapor 

combustion units (VCUs) to avoid 

subjecting VCUs to inappropriate 

requirements. The commenter stated 

that the EPA should allow VCUs to elect 

to meet the proposed flare provisions, as 

was provided in the Gasoline 

Distribution rules. 

Response: In general, we agree with 

the commenter. We note that we had 

proposed specific requirements for 

‘‘enclosed combustion devices’’ so we 

elected to define that term. We 

recognize that some enclosed 

combustion devices may operate more 

like a flare than like an incinerator (no 

direct combustion chamber and no 

means to control the amount of air 

entering the device). In similar 

situations in other rules (gasoline 

distribution rules at 40 CFR part 60, 

subpart XXa, and 40 CFR part 63, 

subparts R and BBBBBB, and the oil and 

gas rule at 40 CFR part 60, subparts 

OOOOb and OOOOc), we have allowed 

the enclosed combustion devices to 

comply with the flare operating limits 

rather than with the temperature 

operating limit. As such, we agree with 

the commenter’s suggestion to allow 

enclosed combustion devices to comply 

with the flare operating limits. We have 

added a definition of both ‘‘enclosed 

combustion device’’ and ‘‘flare’’ to help 

distinguish between these devices 

(enclosed combustion devices emit 

pollutants through a conveyance 

suitable to conduct a performance test, 

and flares have open or shrouded flames 

and do not emit pollutants through a 

conveyance suitable to conduct a 

performance test). We note that the 

implementation of this provision led to 

revision of several paragraphs related to 

control device operating limits and 

monitoring, recordkeeping, and 

reporting requirements to allow 

‘‘enclosed combustion devices electing 

to comply with § 60.112c(d)(5)’’ to be 

treated differently than other non-flare 

combustion devices. We are retaining 

the requirement for enclosed 

combustion devices to conduct a 

performance test to demonstrate that the 

enclosed combustion device is 

achieving a 98 percent VOC emission 

reduction regardless of whether the 

enclosed combustion device is 

complying with the flare operating 

limits in 40 CFR 60.112c(d)(5) or the 

temperature operating limits in 40 CFR 

60.113c(c)(1)(ii)(E). 

Comment: One commenter stated that 

the EPA should clarify in the final NSPS 

subpart Kc rule, in the closed vent 

system and bypass line provisions, that 

open-ended valves or lines that use a 

cap, blind flange, plug, or second valve 

are not considered to be bypass lines. 

According to the commenter, the EPA 

should add the text that is in 40 CFR 

63.2450(e)(6)(v)(B) of the MON rule to 

40 CFR 60.112c(d)(2)(ii) to clearly 

exempt these open-ended valves or lines 

from the bypass requirements. 

Response: We agree with the 

recommendations to align NSPS subpart 

Kc more closely with the provisions in 

the MON regarding open-ended valves 

or lines that use a cap, blind flange, 

plug, or second valve, and have revised 

to 40 CFR 60.112c(d)(2)(ii) accordingly. 

6. Control Standards for Degassing 

Based on the analysis presented at 

proposal, the EPA proposed emptying 

and degassing standards in accordance 

with the BSER applicable to: (1) storage 

vessels equipped with a closed vent 

system routed to a control device, fuel 

gas system, or process; and (2) IFR and 

EFR storage vessels that have a capacity 

of greater than or equal to 1 million 

gallons storing a VOL with an MTVP 

greater than or equal to 1.5 psia. These 

vessels must meet certain requirements 

while the vapors in the storage vessel 

are at or above 10 percent of the LEL. 

The proposed standards of performance 

for degassing emissions reflect a 98 

percent VOC reduction efficiency. 

Regarding degassing controls, we are 

finalizing these provisions with minor 

revisions to what was proposed. We are 

finalizing standards for storage vessels 

subject to controlling degassing 

emissions as proposed. We are 

finalizing a requirement that controls 

must be used until the vapor space 

concentration is less than 10 percent of 

the LEL, as proposed, but we are also 

finalizing provisions for nonflammable 

liquids to comply with a 5,000 ppmv as 

methane concentration level based on 

comments received, because 5,000 

ppmv is equal to 10 percent LEL if the 

vapors were methane. We are finalizing 

that the degassing emissions that must 

be controlled must be vented to control 


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device that achieves a 98 weight percent 

VOC reduction or greater as proposed. 

We are finalizing additional provisions 

to check LEL instrument calibration and 

instrumental offset response each day 

the instrument is used and prior to 

discontinuing controlled degassing 

consistent with LEL measurement 

requirements for IFR monitoring to 

ensure the accuracy of the instrument 

readings. We are also finalizing 

provisions that allow the introduction of 

chemicals or diluents for the purpose of 

reducing vapor concentration before or 

during active degassing, after 

considering comments received. 

Comment: Two commenters stated 

that the EPA should incorporate a 

concentration limit for the storage vessel 

degassing emissions in 40 CFR 

60.112c(e) since nonflammable 

chemicals do not exhibit an LEL. The 

commenter requested that the EPA 

include a concentration limit of less 

than 5,000 ppmv as methane as an 

alternative to the LEL requirement, 

consistent with the National Emission 

Standards for Organic Hazardous Air 

Pollutants From the Synthetic Organic 

Chemical Manufacturing Industry 

proposal. 

Response: We expect that most VOLs 

with an MTVP above 1.5 psia will have 

some flammability, but we agree that a 

concentration limit of 5,000 ppmv as 

methane for nonflammable liquids is 

appropriate because 5,000 ppmv is the 

10 percent LEL of methane and it 

generally provides a concentration value 

that is similar to or lower than the 10 

percent LEL level for heavier organics. 

For example, 10 percent LEL of butane 

is as stringent as or more stringent than 

1,900 ppmv as butane or about 7,600 

ppmv as methane. 

Comment: One commenter noted that 

some companies flood the bottom of the 

tank with a low vapor pressure material 

to facilitate removal of residual sludges 

and/or to reduce the concentration of 

vapors in the vapor space of the tank 

prior to or during active degassing. 

According to the commenter, while the 

proposed rule language does not 

prohibit bottom flushing, this practice 

should be expressly accommodated in 

the rule language. 

Response: We agree that flooding the 

bottom of the tank with a low vapor 

pressure material is a reasonable control 

measure for degassing. As such, we are 

revising 40 CFR 60.112c(e)(1) to 

expressly allow the addition of chemical 

or a diluent for the purpose of reducing 

vapor concentration before or during 

active degassing. 

7. Alternative Means of Emission 

Limitation 

We are finalizing the alternative 

means of emissions limitation (AMEL) 

provisions as proposed except for the 

addition of two clarifications. First, at 

40 CFR 60.114c(a), we are replacing 

‘‘any’’ with ‘‘the applicable’’ when 

referencing requirements in 40 CFR 

60.112c, to clarify that the equivalency 

must be made for the same type of 

control system (IFR, EFR, or closed vent 

system routed to a control device, fuel 

gas system, or process). This 

clarification prevents operators that are 

using an IFR from reducing the fitting 

control requirements finalized for an 

IFR because, for that size of storage 

vessel and stored VOL, the required IFR 

controls achieve greater than a 98 

percent reduction or greater reduction 

than an EFR meeting the final EFR 

requirements. Second, we are clarifying 

that the written application to the 

Administrator in 40 CFR 60.114c(c) may 

include either actual emissions test 

results or an engineering evaluation that 

the Administrator determines to be 

accurate, but it does not necessarily 

have to include both. 

Comment: One commenter noted the 

proposed NSPS subpart Kc provides for 

requesting an AMEL at 40 CFR 60.114c 

and this section specifies that a request 

for approval of an alternative must 

include an actual emissions test; 

however, there are numerous alternative 

control measures that have already been 

tested and for which the EPA has 

published emission factors in AP–42. 

The commenter stated that the EPA 

should not arbitrarily require repeated 

testing for those control measures that 

have already been tested and for which 

the results have already been accepted 

by the EPA. The commenter stated that 

the language in 40 CFR 60.114c should 

be replaced with the language in 

NESHAP subpart WW at 40 CFR 

63.1064. 

Response: We have revised 40 CFR 

60.114c(c) such that an AMEL written 

application must include either an 

actual emissions test (that covers the 

appropriate range of meteorological 

conditions) or an engineering 

evaluation, which may include use of 

emission factors as published in the 

EPA Report No. AP–42, Compilation of 

Air Pollutant Emission Factors. We 

reviewed the AMEL provision in 

NESHAP subpart WW. The NESHAP 

subpart WW provisions include a listing 

of test methods but do not limit the 

testing to those methods. As such, we 

are determining that the language that is 

included in the final rule is equivalent 

to the provisions in NESHAP subpart 

WW. We also note that the provisions in 

40 CFR 63.1064(c) allow the use of 

different combinations of rim and deck 

fitting controls ‘‘. . . if the alternate 

emits no more than the combination 

specified in the § 63.1063.’’ We interpret 

this provision to allow comparisons of 

fitting controls for IFRs to those 

required specifically for IFRs. While we 

consider that the three control options 

we provided are equivalent, we 

acknowledge that, depending on the 

size of tank, volatility of the VOL, and 

prevailing meteorological conditions, 

one of the control configurations (IFR, 

EFR, or closed vent system routed to a 

control device, fuel gas system, or 

process) will perform better and one 

configuration will perform worse than 

the other options allowed. We did not 

intend to allow changes to the specified 

control provisions to only require the 

lowest control efficiency for a given 

combination of tank size, VOL stored, 

and meteorological conditions. 

Therefore, we are also clarifying, 

consistent with our interpretation of the 

NESHAP subpart WW provisions, that 

the AMEL must compare with the 

‘‘applicable’’ requirement. That is, for 

storage vessels with IFRs, you may 

request an AMEL for a different set of 

fittings, but you must show equivalency 

with the IFR requirements specified in 

40 CFR 60.112c(b). For storage vessels 

with EFRs, the AMEL must show 

equivalency with the EFR requirements 

specified in 40 CFR 60.112c(c). For 

storage vessels with a closed vent 

system routed to a control device, fuel 

gas system, or process, the AMEL must 

show equivalency with the control 

requirements specified in 40 CFR 

60.112c(d). With these revisions, we 

determine that the final AMEL 

provisions in NSPS subpart Kc are 

consistent with the AMEL provisions in 

NESHAP subpart WW. 

Since control measures that were 

determined to be equivalent to NSPS 

subpart Kb may not be equivalent to 

controls required under NSPS subpart 

Kc, a new AMEL application must be 

submitted following 40 CFR 60.114c(c) 

in order to demonstrate that an AMEL 

is equivalent to the requirements in 

NSPS subpart Kc. 

C. NSPS Subpart Kc Without Startup, 

Shutdown, and Malfunction Exemptions 

Consistent with Sierra Club v. EPA, 

551 F.3d 1019 (D.C. Cir. 2008), the EPA 

has established standards in this rule 

that apply at all times. We are finalizing 

in NSPS subpart Kc specific 

requirements at 40 CFR 60.110c(g) that 

override the general provisions for SSM 

requirements. In finalizing the standards 

in this rule, the EPA has considered 


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startup and shutdown periods and, for 

the reasons explained in this section of 

the preamble, has not finalized alternate 

standards for those periods. The EPA 

has determined that the reasoning in the 

court’s decision in Sierra Club applies 

equally to CAA section 111 because the 

definition of ‘‘emission standard’’ in 

CAA section 302(k), and the embedded 

requirement for continuous standards, 

also applies to the NSPS. 

Periods of startup, normal operations, 

and shutdown are all predictable and 

routine aspects of a source’s operations. 

Malfunctions, in contrast, are neither 

predictable nor routine. Instead, they 

are, by definition, sudden, infrequent, 

and not reasonably preventable failures 

of emissions control, process, or 

monitoring equipment (40 CFR 60.2). 

The EPA interprets CAA section 111 as 

not requiring emissions that occur 

during periods of malfunction to be 

factored into development of CAA 

section 111 standards. Nothing in CAA 

section 111 or in caselaw requires that 

the EPA consider malfunctions when 

determining what standards of 

performance reflect the degree of 

emission limitation achievable through 

‘‘the application of the best system of 

emission reduction’’ that the EPA 

determines is adequately demonstrated. 

While the EPA accounts for variability 

in setting emissions standards, nothing 

in CAA section 111 requires the Agency 

to consider malfunctions as part of that 

analysis. The EPA is not required to 

treat a malfunction in the same manner 

as the type of variation in performance 

that occurs during routine operations of 

a source. A malfunction is a failure of 

the source to perform in a ‘‘normal or 

usual manner,’’ and no statutory 

language compels the EPA to consider 

such events in setting CAA section 111 

standards of performance. The EPA’s 

approach to malfunctions in the 

analogous circumstances (setting 

‘‘achievable’’ standards under CAA 

section 112) has been upheld as 

reasonable by the D.C. Circuit in U.S. 

Sugar Corp. v. EPA, 830 F.3d 579, 606– 

610 (2016). 

D. Testing, Monitoring, and Inspection 

Requirements 

Because the NSPS reflect the BSER 

under conditions of proper operation 

and maintenance, we also, in 

performing our review, evaluate and 

determine the proper testing, 

monitoring, inspection, recordkeeping, 

and reporting requirements needed to 

ensure compliance with the emission 

standards. This section of the preamble 

includes our discussion of the proposed 

revisions to testing, monitoring, and 

inspection requirements, a summary of 

the significant comments received, our 

responses to the comments, and our 

final determinations regarding testing, 

monitoring, and inspection 

requirements. Changes to recordkeeping 

and reporting requirements are included 

in the section for recordkeeping and 

electronic reporting. 

Generally, we proposed testing, 

monitoring, and inspection 

requirements consistent with those in 

NSPS subpart Kb and other Federal 

standards that would provide the best 

clarity for the specific requirements 

along with the following enhancements. 

The EPA proposed annual LEL 

monitoring as an enhancement to the 

monitoring and inspection requirements 

for storage vessels with IFRs. The EPA 

also proposed equipping floating roof 

storage vessels with a visual or audible 

alarm system to monitor when the 

floating roof approaches specified 

landing heights. For closed vent 

systems, the EPA proposed quarterly 

AVO inspections, annual EPA Method 

21 instrument monitoring, and 

monitoring of bypasses. The EPA also 

proposed that storage vessels using 

closed vent systems routed to control 

devices, fuel gas systems, or processes 

must equip pressure relief devices with 

appropriate monitoring to identify 

releases. For storage vessels with closed 

vent systems routed to a control device, 

the EPA proposed that performance 

tests must be conducted at least once 

every 60 months rather than rely on a 

single initial performance test. Finally, 

the EPA proposed enhanced monitoring 

requirements for flares consistent with 

the Refinery NESHAP (40 CFR 63.671). 

We are finalizing testing, monitoring, 

and inspection requirements as 

proposed except for the revisions 

outlined here. 

• We revised the specification of the 

timing of these requirements to be 

‘‘calendar months’’ rather than just 

‘‘months,’’ to clarify the timing and 

allow limited flexibility when 

scheduling the required testing or 

inspections. 

• For IFRs, we are amending the 

requirements to conduct internal 

inspections of the floating roof at least 

once every 120 calendar months. We are 

retaining this inspection requirement 

each time the vessel is emptied and 

degassed, but we are not requiring 

storage vessels to be taken out of service 

specifically to conduct this inspection. 

• We are making minor revisions to 

the LEL monitoring calibration 

procedures. We proposed language used 

from the gasoline distribution rule (40 

CFR part 63, subpart R), which would 

require the correction factor to be based 

on ‘‘gasoline vapor.’’ Because NSPS 

subpart Kc is applicable to a much 

broader range of chemicals, we are 

revising references to ‘‘gasoline vapors’’ 

to ‘‘vapors of the stored VOL.’’ We are 

retaining the use of butane as the 

surrogate if correction factors are not 

available for the vapors of the VOL 

stored. 

• We are adding specific 

requirements that fittings on EFR must 

be visually inspected during annual seal 

gap measurement inspections to ensure 

that covers are closed and gasketed with 

no visible gaps and that there are no 

tears in sleeves, wipers, or similar 

controls used for a given fitting during 

annual seal gap measurement 

inspections. Visual fitting inspections 

were proposed at 40 CFR 60.113c(b)(7) 

for inspections conducted when the 

storage vessel is emptied and degassed 

but did not specify fitting conditions 

that would result in an inspection 

failure, and we are adding these details 

to clarify the fitting inspection 

requirements based on comments 

received. 

• For closed vent systems, we are 

including an additional reference at 40 

CFR 60.113c(c)(2) for the quarterly AVO 

monitoring as required under both the 

proposed and final requirements at 40 

CFR 60.112c(d)(2)(i). We are also 

revising the provision of 40 CFR 

60.113c(c)(3) to clarify that emissions 

detected using visible, audible, and 

olfactory methods are leaks triggering 

corrective action. 

• Regarding MTVP test methods, we 

are clarifying that owners and operators 

must determine the MTVP of the VOL 

prior to refilling the storage vessel with 

a new VOL. The proposed language only 

referenced ‘‘initial filling’’ and may 

allow facilities to change VOL without 

reassessing the MTVP. However, we 

considered that, when a new VOL is 

stored, that would be an initial filling of 

that VOL. The rephrasing of that 

provision helps to clarify this 

requirement. Additionally, we are 

adding a requirement to use a vapor-toliquid ratio of 4:1 when using American 

Society for Testing and Materials 

(ASTM) D6378–22. We proposed this 

requirement when using ASTM D6377– 

20 but consider that the same provision 

should apply to both of the MTVP test 

methods. The EPA’s intention to use a 

vapor-to-liquid ratio of 4:1 when using 

ASTM D6378–22 was detailed in the 

proposal preamble but was erroneously 

omitted from the proposed rule text. 

• Additionally, as noted in section 

IV.B.5. of this preamble, we are allowing 

enclosed combustion devices to comply 

with the monitoring provisions for flares 

as an alternative to the temperature 

monitoring requirement. 


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Comment: One commenter stated that 

the EPA’s proposed monitoring and 

inspection requirements for floating roof 

tanks are inadequate and must be 

strengthened to make it more likely that 

the tanks can reduce 98 percent of 

VOCs. According to the commenter, at 

a minimum, the EPA must require 

monitoring and inspection in keeping 

with the current requirements from 

South Coast Air Quality Management 

District (SCAQMD) Rule 1178. In 

addition, the commenter stated that the 

EPA must make it explicit that, for IFR 

visual inspections, the entire perimeter 

of the floating roof seal must be visually 

evaluated, even if that requires opening 

multiple manways. The commenter 

stated that the EPA must also require 

quarterly forward-looking infrared 

measurements from tank decks. 

Response: In general, we considered 

that we had incorporated much from the 

SCAQMD Rule 1178 monitoring 

provisions in our proposal. We included 

LEL monitoring provisions for IFR 

storage vessels and PRD monitoring 

provisions for storage vessels with 

closed vent systems routed to a control 

device, fuel gas system, or process that 

are reasonably consistent with the 

monitoring requirements in SCAQMD 

Rule 1178. However, upon further 

review of SCAQMD Rule 1178 and our 

proposed inspection requirements, we 

noted that the inspection requirements 

we proposed for EFR storage vessels 

only covered inspections of the primary 

and secondary seals. Visual fitting 

inspections were proposed for IFR 

inspections and mentioned in the 

proposed inspections at 40 CFR 

60.113c(b)(7) when the storage vessel is 

emptied and degassed. However, no 

requirement for fitting inspections were 

proposed during annual gap 

measurements, and the inspections 

proposed at 40 CFR 60.113c(b)(7) did 

not specify fitting conditions that would 

result in an inspection failure. After our 

review of SCAQMD Rule 1178 

monitoring and inspection requirements 

based on this comment, we are adding 

specific requirements that fittings on 

EFR must be visually inspected during 

annual seal gap measurement 

inspections to ensure that covers are 

closed and gasketed with no visible gaps 

and that there are no tears in sleeves, 

wipers, or similar controls used for a 

given fitting. We are also adding the 

conditions under which an inspection 

failure occurs for the inspections 

conducted when the EFR storage vessel 

is emptied and degassed. 

We considered optical gas imaging 

requirements in previous reviews of 

storage vessels, which we reviewed 

again for NSPS subpart Kc, and 

concluded that these requirements were 

not cost-effective. Regarding manways, 

we agree with the commenter’s assertion 

that while performing IFR visual 

inspections, the entire perimeter of the 

floating roof seal must be visually 

evaluated, even if that requires opening 

multiple manways. We have elected not 

to add specific rule language, because 

we believe that having visual access to 

the entire primary seal, is already a 

necessary component of annual IFR 

inspections both in the rule language of 

NSPS subpart Kc and in the existing 

rule language of NSPS subpart Kb. As 

such, except for the specifications for 

fitting inspections for EFR storage 

vessels, we are not adding additional 

monitoring requirements to NSPS 

subpart Kc. 

Comment: Numerous commenters 

requested that the EPA allow in-service 

inspections of IFRs either by providing 

additional language in 40 CFR 

60.113c(a)(2) allowing for top-side 

inspections when there is visual access 

to all deck components or by 

incorporating an alternate means of 

compliance option to comply with 

NESHAP subpart WW [40 CFR 

63.1063(d)(1) and (2)]. The commenters 

noted that in-service inspections were 

allowed in NSPS subpart Kb to avoid 

the costs and emissions associated with 

emptying and degassing vessels for 

inspection. If in-service inspections are 

provided, the commenters noted, rule 

revisions may also be needed in the 

notification requirements at 40 CFR 

60.116c(b)(1) and the reporting 

requirements at 40 CFR 60.116c(c)(2)(ii). 

Response: We had proposed language 

consistent with NSPS subpart Kb at 40 

CFR 60.113b(a)(4) to require more 

detailed ‘‘out of service’’ inspections at 

least once every 10 years. The EPA 

agrees with the commenter’s request to 

allow for in-service inspections to be 

performed entirely from the top side of 

the floating roof. The EPA is 

incorporating language into 40 CFR 

60.113c(a)(2)(ii) to allow for in-service 

inspections to be performed entirely 

from the top side of the floating roof, as 

long as there is visual access to all deck 

fittings and rim seal systems specified 

in 40 CFR 60.112c(b). We are also 

adding repair timelines in 40 CFR 

60.112c(b), similar to those already 

established for the annual visual 

inspection. We are also specifying that 

a 30-day notification must be provided 

for inspections in 40 CFR 60.116c(b)(1). 

Also, we are deleting the phrase 

‘‘emptied and degassed and’’ from 40 

CFR 60.116c(c)(2)(iii) to account for the 

reporting of these in-service inspections. 

Comment: One commenter stated that 

the calibration requirements for the LEL 

meter in 40 CFR 60.113c(a)(3)(ii) and 

(iv) that are specified for demonstrating 

compliance with the 25 percent LEL 

limit for IFR storage vessels are 

burdensome and should be simplified to 

be consistent with the calibration 

requirements for the LEL meter within 

the storage vessel degassing 

requirements in 40 CFR 60.112c(e). The 

commenter stated that following the 

procedures for ‘‘calibration and 

maintenance according to 

manufacturer’s specifications’’ should 

be adequate for both sections of the rule. 

The commenter recommended that the 

EPA simplify the language in 40 CFR 

60.113c(a)(3)(ii) and (iv) consistent with 

the LEL calibration requirements in the 

storage vessel degassing section. 

Another commenter noted that the 

language at 40 CFR 60.113c(a)(3)(iv) 

references gasoline vapors and should 

be generalized to accommodate other 

stored VOLs. 

Response: We disagree that the LEL 

calibration requirements in 40 CFR 

60.113c(a)(3)(ii) and (iv) are 

burdensome. These paragraphs allow 

the use of manufacturers’ calibration 

methods, and they primarily specify 

when calibration checks must be made 

and specify the LEL span response. 

Upon review of the two LEL monitoring 

requirements, we are adding more 

specific calibration requirements for the 

LEL monitoring instrument used to 

monitor degassing. Specifically, we are 

requiring calibration and zero offset 

checks each day and at the end of the 

degassing event prior to completion to 

confirm that the final readings are 

accurate before controlled degassing can 

be discontinued. 

With respect to the comment 

regarding the reference to gasoline 

vapors in the calibration requirements at 

40 CFR 60.113c(a)(3)(iv), we agree that 

the proposed language needed to be 

generalized. We used calibration 

language from the gasoline distribution 

rule (40 CFR part 63, subpart R), which 

requires the correction factor to be based 

on ‘‘gasoline vapor.’’ Because NSPS 

subpart Kc is applicable to a much 

broader range of chemicals, we are 

revising references to ‘‘gasoline vapors’’ 

to ‘‘vapors of the stored VOL.’’ We are, 

however, retaining the use of butane as 

the surrogate if correction factors are not 

available for the vapors of the VOL 

stored, because a surrogate is needed 

when no published correction factor is 

available for the VOL, and butane is 

considered a reasonable surrogate for 

any VOL that does not have a published 

correction factor. 

Comment: Two commenters stated 

that EPA Method 21 testing is laborious, 

costly, and time-consuming for 


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facilities. One commenter believes that 

the sensory monitoring provisions as 

proposed would place undue burdens 

on operators and would result in 

redundancy in monitoring and 

compliance measures. Both commenters 

stated that when coupled with the 

quarterly sensory testing, the 

requirement for annual EPA Method 21 

testing is unnecessary. One commenter 

submitted a 1997 rule interpretation 

memorandum written by the Texas 

Natural Resource Conservation 

Commission, which explained that the 

EPA Method 21 test under NSPS 

subpart Kb is not considered a 

performance test under 40 CFR 60.8 

since the EPA Method 21 is considered 

a screening measurement rather than a 

performance test, subject to the 

recordkeeping requirements in the 

General Provisions of 40 CFR 60.7(f) and 

not required to be reported by either 

NSPS subpart A or Kb. The commenter 

requested that the EPA discuss whether 

the EPA agrees or disagrees with this 

guidance and whether the interpretation 

also applies to NSPS subpart Kc. 

Response: We disagree that quarterly 

AVO monitoring is burdensome. If a 

leak is found via AVO monitoring, it 

triggers corrective action. Additionally, 

we disagree that annual EPA Method 21 

monitoring is unnecessary, because EPA 

Method 21 will detect small emissions 

sources that are above 500 ppm but that 

would remain undetected by AVO 

monitoring. The closed vent system is to 

be operated ‘‘with no detectable 

emissions as indicated by an instrument 

reading of less than 500 ppm above 

background and visual inspections, as 

determined in part 60, subpart VV, 

§ 60.485(b).’’ In the case of NSPS 

subpart Kb, 40 CFR 60.113b(c) states: 

‘‘The owner or operator of each source 

that is equipped with a closed vent 

system and control device as required in 

§ 60.112b (a)(3) or (b)(2) (other than a 

flare) is exempt from § 60.8 of the 

General Provisions and shall meet the 

following requirements.’’ As such, the 

language in NSPS subpart Kb indicates 

that 40 CFR 60.8 does not apply. 

For NSPS subpart Kc, we used 

language that the closed vent system 

must operate ‘‘. . . with no detectable 

emissions as indicated by an instrument 

reading of less than 500 ppmv above 

background . . .’’ (see 40 CFR 

60.112c(d)(2)), but there is no clear 

exemption from 40 CFR 60.8 in 40 CFR 

60.113c(c)(2). Nonetheless, we agree 

that the requirements in 40 CFR 60.8 do 

not apply to EPA Method 21 instrument 

monitoring under NSPS subpart Kb. 

Unlike in NSPS subpart Kb, we 

proposed and are finalizing reporting 

requirements in NSPS subpart Kc for 

EPA Method 21 instrument monitoring 

events. In reviewing the proposed NSPS 

subpart Kc provisions related to EPA 

Method 21 and AVO monitoring, we 

recognized that we focused on the 

instrument monitoring requirements 

when using EPA Method 21 and 

inadvertently neglected to mention the 

AVO inspection requirements. 

Therefore, we are adding reference to 

the monthly AVO monitoring 

requirement in 40 CFR 60.113c(c)(2) 

consistent with the requirement under 

the proposed and final requirements at 

40 CFR 60.112c(d)(2)(i), and we are 

revising the provision of 40 CFR 

60.113c(c)(3) to clarify that emissions 

detected using AVO methods are 

‘‘leaks’’ triggering corrective action. This 

latter revision also clarifies that leaks 

identified from AVO monitoring do not 

trigger the need to conduct EPA Method 

21 monitoring of an AVO-identified 

leak. In our review, we also identified 

a lack of reporting requirements related 

to AVO-identified leaks. Therefore, we 

have also revised what we proposed for 

recordkeeping requirements at 40 CFR 

60.115c(d)(3)(v) and reporting 

requirements at 40 CFR 60.116c(f)(8)(ii) 

to indicate the type of monitoring 

conducted and to report information 

regarding all leaks identified, not just 

those identified during EPA Method 21 

instrument monitoring. 

Comment: Several commenters 

requested revisions to the vapor 

pressure testing requirements for 

mixtures of indeterminate or variable 

composition to define the term 

‘‘variable’’ and to not require the initial 

and repeat physical testing for liquids 

whose upper and lower bounds of vapor 

pressure are known or are readily 

calculated using standard reference 

texts and good engineering judgment. 

Response: We agree with the 

commenters that the concept of 

‘‘variable compositions’’ of stored liquid 

mixtures for which the proposed rule 

would require initial and repeat 

physical testing to determine MTVP 

could be applied more broadly than 

intended. Thus, in 40 CFR 60.113c(d)(1) 

of the final rule, we are clarifying that 

for mixtures of variable composition, if 

the range of concentrations for each 

constituent is known such that the 

MTVP can be determined from data and 

procedures in standard reference texts, 

then physical testing is not required. 

Similarly, under the final rule, physical 

testing is not required for crude oils and 

refined petroleum products for which 

Reid vapor pressure is known and 

MTVP can be determined from 

nomographs and other procedures 

described in reference texts such as AP– 

42. Additionally, in 40 CFR 

60.113c(d)(2) we have clarified that the 

provisions apply to affected storage 

vessels storing a mixture of 

indeterminate composition or a mixture 

of unknown variable composition. 

E. Recordkeeping and Electronic 

Reporting 

The EPA is finalizing a requirement 

that owners and operators of new, 

modified, or reconstructed VOL storage 

vessels subject to NSPS subpart Kc 

maintain records of the results of 

required testing, monitoring, and 

inspections. The EPA is finalizing a 

requirement that owners and operators 

of VOL storage vessels subject to the 

current and new NSPS at 40 CFR part 

60, subparts Kb and Kc, submit 

electronic copies of required 

performance test reports and the 

semiannual excess emissions and 

continuous monitoring system 

performance and summary reports, 

through the EPA’s Central Data 

Exchange (CDX) using the Compliance 

and Emissions Data Reporting Interface 

(CEDRI). 

We are finalizing the recordkeeping 

and reporting requirements similar to 

those proposed except that some of the 

revisions made to the standards, testing, 

and monitoring provisions required 

revision of the recordkeeping and 

reporting requirements for the final rule. 

The revisions to the proposed 

recordkeeping and reporting 

requirements and our rationale for 

making the revisions are summarized in 

this section. 

• As noted in section IV.D. of this 

preamble, we are revising the 

recordkeeping and reporting 

requirements in 40 CFR 60.115c(d)(3)(v) 

and 60.116c(c)(8)(ii) to include the type 

of monitoring conducted and to report 

information regarding all leaks 

identified, including leaks identified 

using AVO methods. 

• As noted in section IV.B.5. of this 

preamble, we separated PRD monitoring 

requirements to separately address 

devices on storage vessels and devices 

on the closed vent system and included 

provisions to monitor vacuum breaking 

devices on storage vessels. In reviewing 

recordkeeping and reporting 

requirements related to these 

provisions, we noted that we had 

proposed reporting requirements for 

PRDs, but we failed to include 

recordkeeping requirements for PRDs. 

Therefore, we are adding recordkeeping 

requirements at 40 CFR 

60.115c(d)(3)(vii) for PRDs or vacuum 

breaking devices on a storage vessel or 

closed vent system that include: the 

device type; the monitoring device or 

system used for the device; data from 


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the device or system indicating whether 

a pressure release occurred; and the 

date, time, and duration of each 

pressure release, if applicable. We are 

also adding reporting requirements at 40 

CFR 60.116c(c)(12) for each pressure 

release that occurred as a result of a 

vacuum breaking device that failed to 

close prior to the storage vessel reaching 

atmospheric pressure. The added 

reporting requirements include: 

identification of the vacuum breaking 

device; start date, start time, and 

duration (in minutes) of the pressure 

release; and an estimate of the mass 

quantity in pounds of VOL released. 

These requirements mimic the pressure 

release reporting requirements proposed 

(and being finalized) for PRDs, and 

these similar reporting requirements are 

needed to document compliance with or 

deviations from the requirements for 

vacuum breaking devices used for 

storage vessels using a closed vent 

system routed to a control device. 

• As noted in section IV.B.5. of this 

preamble, we are including alternative 

provisions that allow enclosed 

combustion devices to comply with the 

flare operating and monitoring 

requirements. We include minor 

revisions to the proposed recordkeeping 

and reporting requirements 

commensurate with the provided 

alternative, to specify which 

recordkeeping and reporting 

requirements apply to control systems 

‘‘other than flares or enclosed 

combustion devices electing to comply 

with § 60.112c(d)(5)’’ and which 

recordkeeping and reporting 

requirements apply to ‘‘flares or 

enclosed combustion devices electing to 

comply with § 60.112c(d)(5).’’ We are 

also adding a reporting requirement for 

the initial notification at 40 CFR 

60.116c(a)(6) that includes a 

requirement to specify the type of 

control device used and the compliance 

option selected, which, if an enclosed 

combustion device is used, include 

whether the device is complying with a 

temperature operating limit or is instead 

electing to comply with the flare 

requirements in 40 CFR 60.112c(d)(5). 

This initial notification requirement 

will be useful for EPA permitting and 

enforcement personnel to clearly 

understand the compliance option being 

elected for the enclosed combustion 

device. 

• For EFRs, as discussed in section 

IV.D. of this preamble, we added 

requirements to visually inspect the roof 

fittings (such as access hatches, gauge 

floats, gauge hatch/sample wells, rim 

vents, deck drains, deck legs, vacuum 

breakers, pontoon covers, and 

guidepoles) when gap measurements are 

conducted. We are adding to the list at 

40 CFR 60.116c(c)(5)(vi)(A) to include 

reference to deviations of the fitting 

controls outlined in 40 CFR 

60.113c(b)(4)(iii)(A) through (D) to allow 

reporting of fitting deviations identified 

during the gap measurement 

inspections. 

• As discussed in the comment and 

response included in this section of the 

preamble, we are revising what we 

proposed for the timing of semiannual 

compliance reports to either cover fixed 

time periods (from January 1 to June 30 

or July 1 to December 31) or align with 

established reporting dates based on 40 

CFR parts 70 or 71 permit requirements. 

The proposed schedule for semiannual 

reports appeared to require separate 

semiannual reports for different affected 

storage vessels at a facility depending 

on when the storage vessel became 

affected under NSPS subpart Kc. 

Because facilities may have several 

affected storage vessels under NSPS 

subpart Kc, having fixed reporting 

periods simplifies the reporting 

requirements for these facilities. 

Comment: Numerous commenters 

requested that the EPA revise NSPS 

subpart Kc so that reporting 

requirements are consistent with other 

reporting obligations and establish the 

same semiannual reporting deadline for 

all VOL storage vessels. The 

commenters noted that, as proposed, it 

appeared that each affected VOL storage 

vessel could have a separate reporting 

schedule depending on when the 

sources became affected sources under 

NSPS subpart Kc. The commenters 

recommended that the EPA require the 

annual reports to cover activities in set 

time periods (January 1 through June 30 

or July 1 through December 31, as 

applicable). One commenter also 

recommended that the EPA include an 

alternative that would allow each 

affected facility subject to permitting 

regulations pursuant to 40 CFR parts 70 

or 71 to align the semiannual reports 

with established dates for submitting 

semiannual reports pursuant to 40 CFR 

70.6(a)(3)(iii)(A) or 40 CFR 

71.6(a)(3)(iii)(A). 

Response: First, we never intended to 

have different semiannual compliance 

report schedules for different storage 

vessels at a given facility. We note that 

the reporting form template was 

designed to allow reporting of all 

storage vessels at the facility in one 

semiannual report. However, we agree 

that, because the affected facility is each 

VOL storage vessel, the proposed 

requirements at 40 CFR 60.116c(d) 

could be interpreted to impose different 

reporting schedules for different storage 

vessels if they become affected facilities 

in different months. Several 

commenters suggested that the 

semiannual reports cover fixed 

timeframes, specifically January through 

June and July through December. This 

appears reasonable. One commenter 

also suggested including reference to 

semiannual reports under 40 CFR parts 

70 or 71 in the event that the current 

semiannual reporting period is different 

from January through June and July 

through December. This also appears 

reasonable. Therefore, we are providing 

a fixed timeframe for the semiannual 

reports (January through June and July 

through December) and providing an 

alternative timeframe to harmonize with 

other semiannual reports as scheduled 

under 40 CFR parts 70 or 71, if different 

from the fixed timeframe being 

finalized. We clarify that the first 

semiannual compliance report is 

triggered by the date on which the first 

storage vessel at the facility becomes an 

affected facility subject to NSPS subpart 

Kc and would cover, for example, April 

15 through June 30 if the source 

becomes an affected facility on April 15. 

As new storage vessels become affected 

facilities under NSPS subpart Kc, the 

information for those storage vessels 

will be added to the semiannual report. 

These semiannual reporting 

requirements simplify the reporting 

requirements compared to the timing 

proposed and allow alignment of the 

semiannual reports provided for NSPS 

subpart Kc with other reporting 

requirements that may apply for the 

facility. 

F. Other Final Amendments 

1. Editorial Corrections 

We received a number of comments 

regarding editorial, typographical, and 

cross-reference corrections that we agree 

with and are finalizing. Additionally, 

we received comments recommending 

clarification of requirement language to 

reduce misinterpretation. After 

reviewing these comments, we are 

revising some language in the final rule. 

We are revising references of ‘‘a control’’ 

to ‘‘a control device.’’ Beyond these 

changes, the EPA made several revisions 

throughout NSPS subpart Kc to improve 

clarity. 

One commenter recommended that 

the EPA clarify in 40 CFR 60.113c(d)(1) 

that the requirement to determine 

MTVP is not a one-time requirement, as 

implied by the word ‘‘initial,’’ but also 

applies to non-anticipated tank service 

changes. We agree that if the VOL stored 

in the storage vessel changes, the MTVP 

should be reassessed. We are revising 40 

CFR 60.113c(d)(1) to require that this 

determination be made prior to the 


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initial filling of the storage vessel or to 

the refilling of the storage vessel with a 

new VOL. 

One commenter recommended that in 

40 CFR 60.115c(d)(5)(i) and 40 CFR 

60.116c(c)(10)(i)(A) the EPA should add 

‘‘or flare flame’’ to any occurrence of 

‘‘pilot flame’’ consistent with the 

provisions in 40 CFR 60.112c(d)(5)(iv) 

and 40 CFR 60.113c(c)(1)(iv)(B). We are 

revising 40 CFR 60.115c(d)(5)(i) and 40 

CFR 60.116c(c)(10)(i)(A) accordingly. 

2. Definitions 

We received several comments 

recommending the inclusion of 

definitions that were not included in the 

proposal. Additionally, we received 

comments recommending definition 

revisions. This section of the preamble 

summarizes major comments received 

concerning definitions and provides our 

responses to those comments. 

Comment: Several commenters 

recommended that the EPA define the 

term ‘‘pressure relief device’’ in NSPS 

subpart Kc and provided a suggested 

definition: 

Pressure relief device means a valve, 

rupture disk, or similar device used only to 

release an unplanned, nonroutine discharge 

of gas from process equipment in order to 

avoid safety hazards or equipment damage. A 

pressure relief device discharge can result 

from an operator error, a malfunction such as 

a power failure or equipment failure, or other 

unexpected cause. Such devices include 

conventional, spring-actuated relief valves, 

balanced bellows relief valves, pilot-operated 

relief valves, rupture disks, and breaking, 

buckling, or shearing pin devices. Devices 

that are actuated either by a pressure of less 

than or equal to 2.5 pounds per square inch 

gauge or by a vacuum are not pressure relief 

devices. 

Response: We agree with the 

commenters and are including a 

definition of ‘‘pressure relief device’’ in 

NSPS subpart Kc similar to the 

commenters’ suggestion. For storage 

vessels, we consider ‘‘conservation 

vents’’ to be PRDs. These conservation 

vents typically have actuation pressure 

less than 2.5 psig. As such, the last 

sentence in our final definition reflects 

a change from the last sentence in our 

proposed definition to only exclude 

vacuum breaking devices from the 

definition of ‘‘pressure relief devices.’’ 

We are also clarifying that, if a device 

has both a pressure relief function and 

a vacuum breaking function, such as a 

conservation vent, the portion of the 

conservation vent that acts to relieve 

pressure is considered a PRD and the 

portion of the conservation vent that 

acts to relieve vacuum is a vacuum 

breaking device and not a PRD. We are 

also adding a definition of ‘‘vacuum 

breaking device,’’ which is specific to 

the fixed roof portion of the storage 

vessel and a vacuum breaker which is 

a component of a floating roof. 

Comment: One commenter 

recommended that the EPA define the 

term ‘‘pressure release.’’ 

Response: We are adding a definition 

of ‘‘pressure release’’ to 40 CFR 60.111c. 

We are including in the definition of 

‘‘pressure release’’ emissions of 

materials resulting from a vacuum 

breaking device failing to close prior to 

the system reaching atmospheric 

pressure. 

Comment: One commenter 

recommended that the EPA define the 

terms ‘‘vapor balancing system,’’ ‘‘fuel 

gas,’’ ‘‘fuel gas system,’’ and ‘‘routed to 

a process or route to a process.’’ 

Response: We determined that vapor 

balancing is not appropriate or 

equivalent to the BSER identified for 

VOL storage vessels. As such, we are not 

including a definition of ‘‘vapor 

balancing system’’ in NSPS subpart Kc. 

We disagree with the commenter’s 

request to define ‘‘fuel gas’’ because the 

‘‘fuel gas system’’ definition is 

sufficient. We are finalizing definitions 

for ‘‘fuel gas system’’ and ‘‘routed to a 

process or route to a process’’ in NSPS 

subpart Kc. 

Comment: One commenter 

recommended that the EPA define 

‘‘degassing’’ with language consistent 

with the Texas Commission on 

Environmental Quality’s (TCEQ) 

definition. 

Response: The EPA agrees with the 

commenter to define ‘‘degassing’’; 

however, the TCEQ definition is 

insufficient as there may be other 

reasons to empty and degas a storage 

vessel other than cleaning. While we 

agree that cleaning may be a step in the 

process, we expect degassing to occur 

for other reasons. We are finalizing a 

definition for ‘‘degassing’’ in NSPS 

subpart Kc to clarify this point. 

G. Effective Date and Compliance Dates 

Pursuant to CAA section 111(b)(1)(B), 

the effective date of the final rule 

requirements in subpart Kc will be the 

promulgation date. Affected sources that 

commence construction, reconstruction, 

or modification after October 4, 2023, 

must comply with all requirements of 

subpart Kc no later than the effective 

date of the final rule or upon startup, 

whichever is later. The EPA is finalizing 

amendments to NSPS subpart Kb to 

include electronic submission 

requirements. Affected NSPS subpart Kb 

sources that commence construction, 

reconstruction, or modification after 

July 23, 1984, and before October 4, 

2023, must comply with the updated 

requirements to submit reports 

electronically no later than the effective 

date of the final rule. 

V. Summary of Cost, Environmental, 

and Economic Impacts 

A. What are the air quality impacts? 

The final provisions in NSPS subpart 

Kc reduce emissions of VOCs, some of 

which may also be hazardous air 

pollutants (HAPs). The EPA estimates 

that the final standards will reduce VOC 

emissions by 1,085 tons per year, which 

includes the impacts from new, 

modified, and reconstructed storage 

vessels. More information regarding the 

air quality impacts and emission 

reductions are included in the 

memorandum Control Options for 

Storage Vessels (Docket ID No. EPA– 

HQ–OAR–2023–0358–0002). 

B. What are the cost impacts? 

This final action will cost (in 2022 

dollars) approximately $21.1 million in 

total capital cost and result in a total 

annualized cost of $5.38 million per 

year (including product recovery) based 

on our analysis of the final actions in 

NSPS subpart Kc. More information 

about the estimated cost of the final 

actions can be found in the 

memorandum Control Options for 

Storage Vessels (Docket ID No. EPA– 

HQ–OAR–2023–0358–0002). 

C. What are the economic impacts? 

For economic impact analyses (EIA) 

of rules that directly affect a single 

industry or a few industries, the EPA 

often prepares a partial equilibrium 

analysis. In this type of economic 

analysis, the focus of the effort is on 

estimating impacts on a single affected 

industry or several affected industries, 

and all impacts of this rule on industries 

outside of those affected are assumed to 

be zero or so inconsequential as to not 

be considered in the analysis. If the 

compliance costs, which are key inputs 

to an EIA, are quite insignificant, then 

the impact analysis could consist of a 

calculation of annual (or annualized) 

costs as a percentage of sales for affected 

companies. This latter type of analysis 

is called a screening analysis and is 

applied when a partial equilibrium or 

more complex EIA approach is deemed 

not necessary given the expected size of 

the impacts. 

The net present value of the estimated 

cost impacts of NSPS subpart Kc is 

$19.4 million, discounted at a 3 percent 

rate over a 5-year analytic timeframe 

from 2024 to 2028 in 2022 dollars. 

Using a 7 percent discount rate, the net 

present value of the estimated cost 

impacts is $17.3 million. The equivalent 

annualized value in 2022 dollars is a 


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9Technical Guidance for Assessing 

Environmental Justice in Regulatory Analysis, U.S. 

EPA, June 2016. Quote is from Section 3—Key 

Analytic Considerations, page 11. https://

www.epa.gov/environmentaljustice/technicalguidance-assessing-environmental-justiceregulatory-analysis. 

cost of approximately $4.1 million using 

a discount rate of either 3 or 7 percent. 

Storage vessels in NSPS subpart Kb 

are most closely associated with the 

petroleum and coal products industry 

(NAICS 324000), the chemical products 

industry (NAICS 325000), and the 

petroleum bulk stations and terminals 

industry (NAICS 424710). While we do 

not know the precise distribution of 

new and modified storage vessels across 

the affected sectors, we know that there 

are affected storage vessels in the sectors 

mentioned earlier in this preamble. 

These sectors contribute gross value 

added, ranging from $200 to $501 

billion per sector, to the national 

economy. In comparison, the 

requirements in NSPS subpart Kc have 

estimated total costs of $21 million. The 

total cost is the total incurred 

collectively amongst numerous sectors, 

and each of the sectors examined has 

sales of at least $200 billion. Thus, the 

compliance costs of this action are 

insignificant relative to the scale for the 

sectors affected, and it is appropriate to 

evaluate the economic impacts by 

conducting a screening analysis 

comparing the costs to entity-level sales. 

Given the results of the analysis, these 

economic impacts are relatively low for 

affected industries and entities 

impacted by this final rule, and there 

will not be substantial impacts on the 

markets for affected products. The costs 

of the final rule are not expected to 

result in a significant market impact, 

regardless of whether they are passed on 

to the purchaser or absorbed by the 

firms. We also expect minimal impacts 

on employment. 

D. What are the benefits? 

The final provisions in NSPS subpart 

Kc would reduce emissions of VOCs, 

some of which may also be HAPs. 

Because VOCs react in the atmosphere 

to produce ozone, these standards 

would help to reduce atmospheric 

ozone concentrations and reduce health 

effects associated with high levels of 

ozone. Furthermore, the final 

requirements to submit reports and test 

results electronically would improve 

monitoring, compliance, and 

implementation of the rule. 

E. What analysis of environmental 

justice did we conduct? 

For purposes of analyzing regulatory 

impacts, under Executive Order 12898, 

Federal Actions to Address 

Environmental Justice in Minority 

Populations and Low-Income 

Populations, the EPA relies upon its 

June 2016 ‘‘Technical Guidance for 

Assessing Environmental Justice in 

Regulatory Analysis,’’ which provides 

recommendations that encourage 

analysts to conduct the highest quality 

analysis feasible, recognizing that data 

limitations, time, resource constraints, 

and analytical challenges will vary by 

media and circumstance. The Technical 

Guidance states that a regulatory action 

may involve potential EJ concerns if it 

could: (1) create new disproportionate 

impacts on communities with EJ 

concerns; (2) exacerbate existing 

disproportionate impacts on 

communities with EJ concerns; or (3) 

present opportunities to address 

existing disproportionate impacts on 

communities with EJ concerns through 

this action under development. 

The EPA’s EJ technical guidance 

states that ‘‘[t]he analysis of potential EJ 

concerns for regulatory actions should 

address three questions: (A) Are there 

potential EJ concerns associated with 

environmental stressors affected by the 

regulatory action for population groups 

of concern in the baseline? (B) Are there 

potential EJ concerns associated with 

environmental stressors affected by the 

regulatory action for population groups 

of concern for the regulatory option(s) 

under consideration? (C) For the 

regulatory option(s) under 

consideration, are potential EJ concerns 

created or mitigated compared to the 

baseline?’’ 9

Because this action finalizes 

standards of performance for new, 

modified, and reconstructed sources 

that commence construction after 

October 4, 2023, the locations of the 

construction of new VOL storage vessels 

are not known. In addition, it is not 

known which of the existing facilities 

will be modified or reconstructed in the 

future. Therefore, we are unable to 

quantitatively estimate the potential 

environmental justice impact of NSPS 

subpart Kc. Over the next 5 years, the 

EPA estimates that 1,440 new tanks and 

30 modified tanks would be subject to 

NSPS subpart Kc. We estimate that there 

are more than 10,000 existing VOL 

storage vessels, but we do not have a list 

of specific storage vessels and their 

locations. Therefore, we cannot perform 

a proximity demographic analysis of 

populations near existing units as a 

proxy for units that may be modified or 

reconstructed and become subject to 

NSPS subpart Kc. Finally, because we 

based the analysis of the impacts and 

emission reductions on model plants, 

we cannot ascertain specifically how the 

potential benefits of this rule would be 

distributed across the population. Thus, 

we are limited in our ability to estimate 

the potential EJ impacts of this rule. 

The EPA expects that NSPS subpart 

Kc will ensure compliance via revised 

vapor pressure applicability thresholds, 

stricter seal requirements on IFR tanks, 

equivalent control requirements for 

EFRs, and strengthened closed vent 

system standards for vessels routed to a 

control device, fuel gas system, or 

process. This action finalizes standards 

of performance that apply at all times 

(including periods of SSM) and achieve 

an average 98 percent control efficiency. 

The rule will also increase data 

transparency through electronic 

reporting. Therefore, effects of 

emissions on populations in proximity 

to any future affected sources, including 

in communities potentially 

overburdened by pollution, which are 

often communities with EJ concerns, 

will be minimized due to the 

compliance with the standards of 

performance being finalized in this 

action. 

VI. Statutory and Executive Order 

Reviews 

Additional information about these 

statutes and Executive orders can be 

found at https://www.epa.gov/lawsregulations/laws-and-executive-orders. 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 14094: Modernizing Regulatory 

Review 

This action is not a significant 

regulatory action as defined in 

Executive Order 12866, as amended by 

Executive Order 14094, and was 

therefore not subject to a requirement 

for Executive Order 12866 review. 

B. Paperwork Reduction Act (PRA) 

The information collection activities 

in this rule have been submitted for 

approval to OMB under the PRA. The 

Information Collection Request (ICR) 

document that the EPA prepared has 

been assigned EPA ICR number 2791.01. 

You can find a copy of the ICR in the 

docket for this rule, and it is briefly 

summarized here. The information 

collection requirements are not 

enforceable until the Office of 

Management and Budget (OMB) 

approves them. 

The EPA is finalizing requirements for 

storage vessels, including periodic 

inspections based on the type of storage 

vessel. This information will be 

collected to assure compliance with 

NSPS subpart Kc. 


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Respondents/affected entities: 

Owners or operators of VOL storage 

vessels. 

Respondent’s obligation to respond: 

Mandatory (40 CFR part 60, subpart Kc). 

Estimated number of respondents: 

588. 

Frequency of response: Initially and 

semiannually. 

Total estimated burden: 16,394 hours 

(per year). Burden is defined at 5 CFR 

1320.3(b). 

Total estimated cost: $2,009,357 (per 

year), includes $528,240 in annualized 

capital and no operation or maintenance 

costs. 

An agency may not conduct or 

sponsor, and a person is not required to 

respond to, a collection of information 

unless it displays a currently valid OMB 

control number. The OMB control 

numbers for the EPA’s regulations in 40 

CFR are listed in 40 CFR part 9. When 

OMB approves this ICR, the Agency will 

announce that approval in the Federal 

Register and publish a technical 

amendment to 40 CFR part 9 to display 

the OMB control number for the 

approved information collection 

activities contained in this final rule. 

C. Regulatory Flexibility Act (RFA) 

I certify that this action will not have 

a significant economic impact on a 

substantial number of small entities 

under the RFA. The small entities 

subject to the requirements of this 

action are small businesses and small 

governmental jurisdictions that own or 

operate VOL storage vessels. The 

Agency has determined that small 

entities may experience an impact of 

likely below 1 percent relative to sales 

for any affected small entity, and an 

even larger margin before it would 

approach a 1 percent impact for a 

substantial number of small entities. 

Details of this analysis are presented in 

the memorandum Economic Impact 

Analysis for the New Source 

Performance Standards (NSPS) for the 

Volatile Organic Liquid Storage Vessels 

(Tanks) included in the docket. 

D. Unfunded Mandates Reform Act 

(UMRA) 

This action does not contain an 

unfunded mandate of $100 million or 

more as described in UMRA, 2 U.S.C. 

1531–1538, and does not significantly or 

uniquely affect small governments. The 

action imposes no enforceable duty on 

any State, local, or Tribal governments 

or the private sector. 

E. Executive Order 13132: Federalism 

This action does not have federalism 

implications. It will not have substantial 

direct effects on the States, on the 

relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

This action does have Tribal 

implications as specified in Executive 

Order 13175. NSPS subpart Kb includes 

provisions for storage vessels that 

already have impacts on Tribal 

governments that have storage vessels 

with at least 20,000 gallons of capacity 

and that meet the vapor pressure 

thresholds for general rule applicability 

or control applicability. NSPS subpart 

Kc includes updates to the VOC 

standards and monitoring requirements 

for storage vessels that meet the revised 

vapor pressure thresholds for control. 

Additionally, basic requirements for 

determining a VOL’s MTVP, 

recordkeeping, and good air pollution 

control practices are being finalized for 

all storage vessels greater than 20,000 

gallons that only store VOLs with an 

MTVP greater than or equal to 0.25 psia. 

These changes will only impact storage 

vessels that are constructed, modified, 

or reconstructed after the proposal date. 

Consistent with the EPA Policy on 

Consultation and Coordination with 

Indian Tribes, the EPA offered 

government-to-government consultation 

with Tribes by sending a letter dated 

October 3, 2023, inviting all federally 

recognized Tribes to request a 

consultation. The EPA received one 

request for consultation. On November 

8, 2023, the EPA met with the Tribe for 

the purposes of discussing NSPS 

subpart Kc and other issues but were 

unable to conduct consultation on this 

specific rulemaking. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

Executive Order 13045 directs Federal 

agencies to include an evaluation of the 

health and safety effects of the planned 

regulation on children in Federal health 

and safety standards and explain why 

the regulation is preferable to 

potentially effective and reasonably 

feasible alternatives. This action is not 

subject to Executive Order 13045 

because it is not economically 

significant as defined in Executive 

Order 12866 and because the EPA does 

not believe the environmental health or 

safety risks addressed by this action 

present a disproportionate risk to 

children. The final rule will reduce 

emissions of VOCs, some of which may 

also be HAPs. These standards will help 

to reduce atmospheric ozone 

concentrations and reduce health effects 

associated with high levels of ozone and 

are projected to improve overall health, 

including that of children. 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not subject to Executive 

Order 13211, because it is not a 

significant regulatory action under 

Executive Order 12866. 

I. National Technology Transfer and 

Advancement Act (NTTAA) and 1 CFR 

Part 51 

This action for NSPS subparts Kb and 

Kc involves technical standards. 

Therefore, the EPA conducted a search 

to identify potentially applicable 

voluntary consensus standards. 

However, the Agency identified no such 

standards. Searches were conducted for 

EPA Methods 1, 1A, 2, 2A, 2C, 2D, 3A, 

3B, 3C, 4, 6, 10, 15, 16, 16A, 18, 21, 22, 

and 25A of 40 CFR part 60, appendix A. 

The EPA has decided to use EPA 

Methods 21, 22, and 25A. Additional 

information for the voluntary consensus 

standard search and determinations can 

be found in the memorandum titled, 

Voluntary Consensus Standard Results 

for Review of Standards of Performance 

for Volatile Organic Liquid Storage 

Vessels (Including Petroleum Liquid 

Storage Vessels). All potential standards 

were reviewed to determine the 

practicality of the voluntary consensus 

standards for this rule. Although there 

were no applicable voluntary consensus 

standards identified, we are finalizing 

the proposal to amend 40 CFR 60.17 to 

incorporate by reference two ASTM 

methods as discussed in section III.M. of 

the proposal preamble (88 FR 68550; 

October 4, 2023). These include the 

following: 

• 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 °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 HydrocarbonOxygenate Mixtures (Triple Expansion 

Method). The method is an automated 

device method for measuring vapor 

pressures between 7 kPa and 150 kPa at 

37.8 °C for tested samples with boiling 

points at 0 °C. The method is suitable 

for volatile organic liquids, 


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hydrocarbons and liquid petroleum 

products sampled at a 4:1 vapor-liquid 

ratio. 

The ASTM standards are available 

from ASTM, International, 100 Barr 

Harbor Drive, Post Office Box C700, 

West Conshohocken, PA 19428–2959. 

See https://www.astm.org. 

J. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations and Executive 

Order 14096: Revitalizing Our Nation’s 

Commitment to Environmental Justice 

for All 

The EPA believes that it is not 

practicable to assess whether the human 

health or environmental conditions that 

exist prior to this action result in 

disproportionate and adverse effects on 

communities with EJ concerns. Over the 

next 5 years, the EPA estimates that 

1,440 new tanks and 30 modified tanks 

will be subject to NSPS subpart Kc. 

However, the locations of any new VOL 

storage vessels that would be subject to 

NSPS subpart Kc are not known. 

Furthermore, there is insufficient data 

available regarding the locations of 

existing VOL storage vessels. The EPA 

estimates that there are more than 

10,000 existing storage vessels subject to 

NSPS subpart Kb, but we do not have 

a list of specific storage vessels and their 

locations. Therefore, we cannot perform 

a proximity demographic analysis of 

populations near existing storage vessels 

as a proxy for storage vessels that may 

be modified or reconstructed and 

become subject to NSPS subpart Kc. 

Finally, because we based the analysis 

of the impacts and emission reductions 

on model plants, we cannot ascertain 

specifically how the potential benefits 

of this rule would be distributed across 

the population. Thus, we are limited in 

our ability to estimate the potential EJ 

impacts of this rule. 

The information supporting this 

Executive Order review is contained in 

section V.E. of this document. All 

pertinent supporting documents such as 

the technical memorandum, Control 

Options for Storage Vessels (Docket ID 

No. EPA–HQ–OAR–2023–0358–0002), 

which discusses the costs and 

environmental impacts of the regulatory 

options considered, is in the docket. 

K. Congressional Review Act (CRA) 

This action is subject to the CRA, and 

the EPA will submit a rule report to 

each House of the Congress and to the 

Comptroller General of the United 

States. This action is not a ‘‘major rule’’ 

as defined by 5 U.S.C. 804(2). 

List of Subjects in 40 CFR Part 60 

Environmental protection, 

Administrative practice and procedures, 

Air pollution control, Incorporation by 

reference, Reporting and recordkeeping 

requirements. 

Michael S. Regan, 

Administrator. 

For the reasons set forth in the 

preamble, the Environmental Protection 

Agency is amending part 60 of title 40, 

chapter I, of the Code of Federal 

Regulations as follows: 

PART 60—STANDARDS OF 

PERFORMANCE FOR NEW 

STATIONARY SOURCES 

■ 1. The authority citation for part 60 

continues to read as follows: 

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

Subpart A—General Provisions 

■ 2. Amend § 60.17 by: 

■ a. Redesignating paragraphs (h)(198) 

through (233) as (h)(200) through (235); 

and 

■ b. Adding paragraphs (h)(198) and 

(199). 

The additions read as follows: 

§ 60.17 Incorporations by reference. 

* * * * * 

(h) * * * 

(198) ASTM D6377–20, Standard Test 

Method for Determination of Vapor 

Pressure of Crude Oil: VPCRx

(Expansion Method), (Approved June 1, 

2020); IBR approved for § 60.113c. 

(199) ASTM–D6378–22, Standard 

Test Method for Determination of Vapor 

Pressure (VPX) of Petroleum Products, 

Hydrocarbons, and HydrocarbonOxygenate Mixtures (Triple Expansion 

Method), (Approved July 1, 2022); IBR 

approved for § 60.113c. 

* * * * * 

Subpart Kb—Standards of 

Performance for Volatile Organic 

Liquid Storage Vessels (Including 

Petroleum Liquid Storage Vessels) for 

Which Construction, Reconstruction, 

or Modification Commenced After July 

23, 1984, and On or Before October 4, 

2023 

■ 3. Revise the heading of subpart Kb to 

read as set out above. 

■ 4. Amend § 60.110b by revising 

paragraph (a) to read as follows: 

§ 60.110b Applicability and designation of 

affected facility. 

(a) Except as provided in paragraph 

(b) of this section, the affected facility to 

which this subpart applies is each 

storage vessel with a capacity greater 

than or equal to 75 cubic meters (m3) 

that is used to store volatile organic 

liquids (VOL) for which construction, 

reconstruction, or modification is 

commenced after July 23, 1984, and on 

or before October 4, 2023. 

* * * * * 

■ 5. Amend § 60.115b by: 

■ a. Revising paragraphs (a), (b), and (d); 

and 

■ b. Adding paragraphs (e), (f), and (g). 

The revisions and additions read as 

follows: 

§ 60.115b Reporting and recordkeeping 

requirements. 

* * * * * 

(a) After installing control equipment 

in accordance with § 60.112b(a)(1) 

(fixed roof and internal floating roof), 

the owner or operator shall meet the 

following requirements. 

(1) Furnish the Administrator with a 

report that describes the control 

equipment and certifies that the control 

equipment meets the specifications of 

§ 60.112b(a)(1) and § 60.113b(a)(1). Prior 

to October 15, 2024, this report shall be 

an attachment to the notification 

required by § 60.7(a)(3). Beginning 

October 15, 2024, the owner or operator 

must submit all subsequent reports in 

PDF format following the procedures 

specified in paragraph (e) of this 

section. 

(2) Keep a record of each inspection 

performed as required by 

§ 60.113b(a)(1), (a)(2), (a)(3), and (a)(4). 

Each record shall identify the storage 

vessel on which the inspection was 

performed and shall contain the date the 

vessel was inspected and the observed 

condition of each component of the 

control equipment (seals, internal 

floating roof, and fittings). 

(3) If any of the conditions described 

in § 60.113b(a)(2) are detected during 

the annual visual inspection required by 

§ 60.113b(a)(2), a report shall be 

furnished to the Administrator within 

30 days of the inspection. Each report 

shall identify the storage vessel, the 

nature of the defects, and the date the 

storage vessel was emptied or the nature 

of and date the repair was made. 

Beginning October 15, 2024, all 

subsequent reports must be submitted in 

PDF format following the procedures in 

paragraph (e) of this section. 

(4) After each inspection required by 

§ 60.113b(a)(3) that finds holes or tears 

in the seal or seal fabric, or defects in 

the internal floating roof, or other 

control equipment defects listed in 

§ 60.113b(a)(3)(ii), a report shall be 

furnished to the Administrator within 

30 days of the inspection. The report 

shall identify the storage vessel and the 


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reason it did not meet the specifications 

of § 60.112b(a)(1) or § 60.113b(a)(3) and 

list each repair made. Beginning 

October 15, 2024, all subsequent reports 

must be submitted in PDF format 

following the procedures in paragraph 

(e) of this section. 

(b) After installing control equipment 

in accordance with § 60.112b(a)(2) 

(external floating roof), the owner or 

operator shall meet the following 

requirements. 

(1) Furnish the Administrator with a 

report that describes the control 

equipment and certifies that the control 

equipment meets the specifications of 

§ 60.112b(a)(2) and § 60.113b(b)(2), 

(b)(3), and (b)(4). Prior to October 15, 

2024, this report shall be an attachment 

to the notification required by 

§ 60.7(a)(3). Beginning October 15, 2024, 

the owner or operator must submit all 

subsequent reports in PDF format 

following the procedures specified in 

paragraph (e) of this section. 

(2) Within 60 days of performing the 

seal gap measurements required by 

§ 60.113b(b)(1), furnish the 

Administrator with a report that 

contains the following information. 

Beginning October 15, 2024, all 

subsequent reports must be submitted in 

PDF format following the procedures in 

paragraph (e) of this section. 

(i) The date of measurement; 

(ii) The raw data obtained in the 

measurement; and 

(iii) The calculations described in 

§ 60.113b(b)(2) and (b)(3). 

(3) Keep a record of each gap 

measurement performed as required by 

§ 60.113b(b). Each record shall identify 

the storage vessel in which the 

measurement was performed and shall 

contain: 

(i) The date of measurement; 

(ii) The raw data obtained in the 

measurement; and 

(iii) The calculations described in 

§ 60.113b(b)(2) and (b)(3). 

(4) After each seal gap measurement 

that detects gaps exceeding the 

limitations specified by § 60.113b(b)(4), 

submit a report to the Administrator 

within 30 days of the inspection. The 

report will identify the vessel and 

contain the information specified in 

paragraph (b)(2) of this section and the 

date the vessel was emptied or the 

repairs made and date of repair. 

Beginning October 15, 2024, all 

subsequent reports must be submitted in 

PDF format following the procedures in 

paragraph (e) of this section. 

* * * * * 

(d) After installing a closed vent 

system and flare to comply with 

§ 60.112b, the owner or operator shall 

meet the following requirements. 

(1) A report containing the 

measurements required by § 60.18(f)(1) 

through (6) shall be furnished to the 

Administrator as required by § 60.8 of 

the General Provisions. This report shall 

be submitted within 6 months of the 

initial start-up date. Beginning October 

15, 2024, all subsequent reports must be 

submitted in PDF format following the 

procedures in paragraph (e) of this 

section. 

(2) Records shall be kept of all periods 

of operation during which the flare pilot 

flame is absent. 

(3) Semiannual reports of all periods 

recorded under § 60.115b(d)(2) in which 

the pilot flame was absent shall be 

furnished to the Administrator. 

Beginning October 15, 2024, all 

subsequent reports must be submitted in 

PDF format following the procedures 

specified in paragraph (e) of this 

section. 

(e) An owner or operator required to 

submit notifications or reports following 

the procedures specified in this 

paragraph (e) must submit notifications 

or reports to the EPA via the 

Compliance and Emissions Data 

Reporting Interface (CEDRI), which can 

be accessed through the EPA’s Central 

Data Exchange (CDX) (https://

cdx.epa.gov/). The EPA will make all 

the information submitted through 

CEDRI available to the public without 

further notice to the owner or operator. 

Do not use CEDRI to submit information 

the owner or operator claims as CBI. 

Although the EPA does not expect 

persons to assert a claim of CBI, if an 

owner or operator wishes to assert a CBI 

claim for some of the information in the 

report or notification, the owner or 

operator must submit a complete file in 

the format specified in this subpart, 

including information claimed to be 

CBI, to the EPA following the 

procedures in paragraphs (e)(1) and (2) 

of this section. Clearly mark the part or 

all of the information claimed to be CBI. 

Information not marked as CBI may be 

authorized for public release without 

prior notice. Information marked as CBI 

will not be disclosed except in 

accordance with procedures set forth in 

40 CFR part 2. All CBI claims must be 

asserted at the time of submission. 

Anything submitted using CEDRI cannot 

later be claimed CBI. Furthermore, 

under CAA section 114(c), emissions 

data is not entitled to confidential 

treatment, and the EPA is required to 

make emissions data available to the 

public. Thus, emissions data will not be 

protected as CBI and will be made 

publicly available. The owner or 

operator must submit the same file 

submitted to the CBI office with the CBI 

omitted to the EPA via the EPA’s CDX 

as described earlier in this paragraph 

(e). 

(1) The preferred method to receive 

CBI is for it to be transmitted 

electronically using email attachments, 

File Transfer Protocol, or other online 

file sharing services. Electronic 

submissions must be transmitted 

directly to the OAQPS CBI Office at the 

email address oaqpscbi@epa.gov, and as 

described above, should include clear 

CBI markings, and be flagged to the 

attention of the NSPS Kb Lead. Owners 

and operators who do not have their 

own file sharing service and who 

require assistance with submitting large 

electronic files that exceed the file size 

limit for email attachments should 

email oaqpscbi@epa.gov to request a file 

transfer link. 

(2) If an owner or operator cannot 

transmit the file electronically, the 

owner or operator may send CBI 

information through the postal service 

to the following address: U.S. EPA, 

Attn: OAQPS Document Control Officer 

and NSPS Kb Lead, Mail Drop: C404– 

02, 109 T.W. Alexander, P.O. Box 

12055, RTP, NC 27711. The mailed CBI 

material should be double wrapped and 

clearly marked. Any CBI markings 

should not show through the outer 

envelope. 

(f) Owners and operators required to 

electronically submit notifications or 

reports through CEDRI in the EPA’s 

CDX may assert a claim of EPA system 

outage for failure to timely comply with 

the electronic submittal requirement. To 

assert a claim of EPA system outage, 

owners and operators must meet the 

requirements outlined in paragraphs 

(f)(1) through (7) of this section. 

(1) The owner or operator must have 

been or will be precluded from 

accessing CEDRI and submitting a 

required report within the time 

prescribed due to an outage of either the 

EPA’s CEDRI or CDX systems. 

(2) The outage must have occurred 

within the period of time beginning 5 

business days prior to the date that the 

submission is due. 

(3) The outage may be planned or 

unplanned. 

(4) The owner or operator must 

submit notification to the Administrator 

in writing as soon as possible following 

the date the owner or operator first 

knew, or through due diligence should 

have known, that the event may cause 

or has caused a delay in reporting. 

(5) The owner or operator must 

provide to the Administrator a written 

description identifying: 

(i) The date(s) and time(s) when CDX 

or CEDRI was accessed and the system 

was unavailable; 


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(ii) A rationale for attributing the 

delay in reporting beyond the regulatory 

deadline to EPA system outage; 

(iii) A description of measures taken 

or to be taken to minimize the delay in 

reporting; and 

(iv) The date by which the owner or 

operator proposes to report, or if the 

owner or operator has already met the 

reporting requirement at the time of the 

notification, the date the report was 

submitted. 

(6) The decision to accept the claim 

of EPA system outage and allow an 

extension to the reporting deadline is 

solely within the discretion of the 

Administrator. 

(7) In any circumstance, the report 

must be submitted electronically as 

soon as possible after the outage is 

resolved. 

(g) Owners and operators required to 

electronically submit notifications or 

reports through CEDRI in the EPA’s 

CDX may assert a claim of force majeure 

for failure to timely comply with the 

electronic submittal requirement. To 

assert a claim of force majeure, you 

must meet the requirements outlined in 

paragraphs (g)(1) through (5) of this 

section. 

(1) An owner or operator may submit 

a claim if a force majeure event is about 

to occur, occurs, or has occurred or 

there are lingering effects from such an 

event within the period of time 

beginning 5 business days prior to the 

date the submission is due. For the 

purposes of this section, a force majeure 

event is defined as an event that will be 

or has been caused by circumstances 

beyond the control of the affected 

facility, its contractors, or any entity 

controlled by the affected facility that 

prevents the owner or operator from 

complying with the requirement to 

submit a report electronically within the 

time period prescribed. Examples of 

such events are acts of nature (e.g., 

hurricanes, earthquakes, or floods), acts 

of war or terrorism, or equipment failure 

or safety hazard beyond the control of 

the affected facility (e.g., large scale 

power outage). 

(2) The owner or operator must 

submit notification to the Administrator 

in writing as soon as possible following 

the date the owner or operator first 

knew, or through due diligence should 

have known, that the event may cause 

or has caused a delay in reporting. 

(3) The owner or operator must 

provide to the Administrator: 

(i) A written description of the force 

majeure event; 

(ii) A rationale for attributing the 

delay in reporting beyond the regulatory 

deadline to the force majeure event; 

(iii) A description of measures taken 

or to be taken to minimize the delay in 

reporting; and 

(iv) The date by which the owner or 

operator proposes to report, or if the 

owner or operator has already met the 

reporting requirement at the time of the 

notification, the date the report was 

submitted. 

(4) The decision to accept the claim 

of force majeure and allow an extension 

to the reporting deadline is solely 

within the discretion of the 

Administrator. 

(5) In any circumstance, the reporting 

must occur as soon as possible after the 

force majeure event occurs. 

■ 6. Amend § 60.116b by revising 

paragraph (d) to read as follows: 

§ 60.116b Monitoring of operations. 

* * * * * 

(d) Except as provided in paragraph 

(g) of this section, the owner or operator 

of each storage vessel either with a 

design capacity greater than or equal to 

151 m3 storing a liquid with a maximum 

true vapor pressure that is normally less 

than 5.2 kPa or with a design capacity 

greater than or equal to 75 m3 but less 

than 151 m3 storing a liquid with a 

maximum true vapor pressure that is 

normally less than 27.6 kPa shall notify 

the Administrator within 30 days when 

the maximum true vapor pressure of the 

liquid exceeds the respective maximum 

true vapor pressure values for each 

volume range. Beginning October 15, 

2024, all subsequent notifications must 

be submitted in PDF format following 

the procedures specified in § 60.115b(e). 

* * * * * 

■ 7. Amend § 60.117b by revising 

paragraph (b) to read as follows: 

§ 60.117b Delegation of authority. 

* * * * * 

(b) Authorities which will not be 

delegated to States: §§ 60.111b(f)(4), 

60.114b, 60.116b(e)(3)(iii), 

60.116b(e)(3)(iv), and 60.116b(f)(2)(iii), 

and approval of an alternative to any 

electronic reporting to the EPA required 

by this subpart. 

■ 8. Add subpart Kc consisting of 

§§ 60.110c through 60.117c to part 60 to 

read as follows: 

Subpart Kc—Standards of 

Performance for Volatile Organic 

Liquid Storage Vessels (Including 

Petroleum Liquid Storage Vessels) for 

Which Construction, Reconstruction, 

or Modification Commenced After 

October 4, 2023 

Sec. 

60.110c Applicability and designation of 

affected facility. 

60.111c Definitions. 

60.112c Standard for volatile organic 

compounds (VOC). 

60.113c Testing, monitoring, and inspection 

procedures. 

60.114c Alternative means of emission 

limitation. 

60.115c Recordkeeping requirements. 

60.116c Reporting requirements. 

60.117c Delegation of authority. 

§ 60.110c Applicability and designation of 

affected facility. 

(a) Except as provided in paragraph 

(b) of this section, the affected facility to 

which this subpart applies is each 

storage vessel with a capacity greater 

than or equal to 20,000 gallons (gal) 

(75.7 cubic meters (m3)) that is used to 

store volatile organic liquids (VOL) for 

which construction, reconstruction, or 

modification is commenced after 

October 4, 2023. 

(b) This subpart does not apply to the 

following: 

(1) Vessels at coke oven by-product 

plants; 

(2) Pressure vessels designed to 

operate in excess of 29.7 pounds per 

square inch absolute (psia) (204.9 

kilopascals (kPa) absolute) and without 

emissions to the atmosphere; 

(3) Vessels permanently attached to 

mobile vehicles such as trucks, railcars, 

barges, or ships; 

(4) Vessels with a design capacity less 

than or equal to 420,000 gal (1,589.874 

m3) used for petroleum or condensate 

stored, processed, or treated prior to 

custody transfer; 

(5) Vessels located at bulk gasoline 

plants as defined in 40 CFR 63.11100; 

(6) Vessels located at gasoline service 

stations; 

(7) Vessels used to store beverage 

alcohol; or 

(8) Vessels that only store VOL with 

a maximum true vapor pressure less 

than 0.25 psia (1.7 kPa absolute). 

(c) Storage vessels that are affected 

facilities according to paragraph (a) of 

this section for which construction or 

reconstruction commenced after 

October 4, 2023 are subject to the 

standards in § 60.112c and the 

corresponding requirements in 

§§ 60.113c through 60.116c as new 

sources any time they meet the 

specifications in either paragraph (c)(1) 

or (2) of this section, regardless of 

whether they initially contained VOL 

with a maximum true vapor pressure 

below the applicable threshold in 

paragraph (c)(1) or (2) of this section. 

(1) Storage vessels with a capacity 

greater than or equal to 40,000 gal (151 

m3) containing a VOL that, as stored, 

has a maximum true vapor pressure 

equal to or greater than 0.5 psia (3.4 

kPa). 

(2) Storage vessels with a capacity 

greater than or equal to 20,000 gal (75.7 


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m3) but less than 40,000 gal (151 m3) 

containing a VOL that, as stored, has a 

maximum true vapor pressure equal to 

or greater than 1.5 psia (10.3 kPa). 

(d) Storage vessels that are affected 

facilities according to paragraph (a) of 

this section for which construction or 

reconstruction commenced on or before 

October 4, 2023, (‘‘existing storage 

vessels’’) and are modified after October 

4, 2023, are subject to the standards in 

§ 60.112c and the corresponding 

requirements in §§ 60.113c through 

60.116c as modified sources any time 

they meet the specifications in either 

paragraph (d)(1) or (2) of this section. 

(1) For an existing storage vessel with 

a capacity greater than or equal to 

40,000 gal (151 m3), containing a VOL 

that, as stored, has a maximum true 

vapor pressure equal to or greater than 

0.5 psia (3.4 kPa). 

(2) For an existing storage vessel with 

a capacity greater than or equal to 

20,000 gal (75.7 m3) but less than 40,000 

gal (151 m3), containing a VOL that, as 

stored, has a maximum true vapor 

pressure equal to or greater than 1.5 psia 

(10.3 kPa). 

(e) For the purposes of this subpart, 

(1) The phrase ‘‘change in the method 

of operation of, an existing facility 

which increases the amount of any air 

pollutant’’ in the definition of 

modification in § 60.2 or ‘‘operational 

change to an existing facility which 

results in an increase in the emission 

rate to the atmosphere of any pollutant 

to which a standard applies’’ in 

§ 60.14(a) means a change in operation 

occurs if the storage vessel is used to 

store a VOL that has a greater maximum 

true vapor pressure than all VOL 

historically stored or permitted; and 

(2) The exemption in § 60.14(e)(4) 

regarding alternative fuel or raw 

material does not apply to storage 

vessels. 

(f) Storage vessels that are affected 

facilities according to paragraph (a) of 

this section and do not meet the criteria 

in either paragraph (c)(1), (c)(2), (d)(1), 

or (d)(2) of this section are subject to the 

requirements in § 60.113c(d), if 

applicable, and § 60.115c(b). 

(g) All standards including emission 

limitations shall apply at all times, 

including periods of startup, shutdown 

and malfunction. As provided in 

§ 60.11(f), this paragraph (g) supersedes 

the exemptions for periods of startup, 

shutdown, and malfunction in subpart 

A of this part. 

(h) Owners or operators may choose 

to comply with the provisions of this 

subpart to demonstrate compliance with 

subparts K, Ka, and Kb of this part. 

Compliance with the provisions of this 

subpart, including all control 

requirements, recordkeeping, and 

reporting requirements, will constitute 

compliance with the applicable storage 

vessel provisions in subparts K, Ka, and 

Kb. 

(i) Owners or operators may choose to 

comply with this subpart to demonstrate 

compliance with 40 CFR part 63, 

subpart WW for storage vessels 

equipped with an internal or external 

floating roof that is subject to this 

subpart and 40 CFR part 63, subpart 

WW. Compliance with this subpart, 

including all floating roof requirements, 

recordkeeping, and reporting 

requirements, will constitute 

compliance with the applicable storage 

vessel provisions in 40 CFR part 63, 

subpart WW. 

§ 60.111c Definitions. 

Terms used in this subpart are 

defined in the Act, in subpart A of this 

part, or in this section as follows: 

Access hatch means an opening in the 

roof with a vertical well and a cover 

attached to it. Access hatch provides 

passage for workers and materials 

through the roof for construction or 

maintenance. 

Condensate means hydrocarbon 

liquid separated from natural gas that 

condenses due to changes in the 

temperature or pressure, or both, and 

remains liquid at standard conditions. 

Closed vent system means a system 

that is not open to the atmosphere and 

is composed of piping, ductwork, 

connections, and, if necessary, flow 

inducing devices that transport gas or 

vapor from an emission point to a 

control device. Closed vent system does 

not include the vapor collection system 

that is part of any tank truck or railcar. 

Custody transfer means the transfer of 

produced petroleum and/or condensate, 

after processing and/or treatment in the 

producing operations, from storage 

vessels or automatic transfer facilities to 

pipelines or any other forms of 

transportation. 

Degassing means the process of 

removing VOL vapors from a storage 

vessel during, or in preparation of, 

cleaning or when taking the storage 

vessel out of service for inspection, 

repair, or other reason. 

Enclosed combustion device means a 

thermal combustion device used to mix 

and ignite fuel, air pollutants, and air to 

provide a flame to heat and oxidize air 

pollutants and that emits the oxidized 

pollutants through a conveyance 

suitable to conduct a performance test. 

An enclosed combustion device may 

have recovery heat to preheat 

combustion air, but its primary purpose 

is for emission control and not to 

produce useful heat. Enclosed 

combustion devices include, but are not 

limited to, thermal oxidizers and 

incinerators. For the purpose of this 

subpart, process heaters and boilers are 

not enclosed combustion devices. 

External floating roof means a 

pontoon-type or double-deck type cover 

that rests on the liquid surface in a 

storage vessel without a fixed roof. 

Fill means the introduction of VOL 

into a storage vessel but not necessarily 

to complete capacity. 

Flare means a thermal combustion 

device using an open or shrouded flame 

(without full enclosure) such that the 

pollutants are not emitted through a 

conveyance suitable to conduct a 

performance test. 

Fuel gas system means the offsite and 

onsite piping and control system that 

gathers gaseous stream(s) generated by 

onsite operations, may blend them with 

other sources of gas, and transports the 

gaseous stream for use as fuel gas in 

combustion devices, or in- process 

combustion equipment such as furnaces 

and gas turbines, either singly or in 

combination. 

Gasoline service station means any 

site where gasoline is dispensed to 

motor vehicle fuel tanks from stationary 

storage vessels. 

Gauge float means a device that is 

used to indicate the level of liquid 

within the storage vessel. The float rests 

on the liquid surface and is housed 

inside a well that is closed by a 

removable cover. 

Gauge hatch/sample port/sample well 

means an opening in the roof that 

provides access for gauging or sampling. 

A gauge hatch is usually equipped with 

a closing cover or a funnel and slitfabric seal to cover the opening. 

Internal floating roof means a floating 

roof located in a storage vessel with a 

fixed roof. For the purposes of this 

subpart, an external floating roof located 

in a storage vessel to which a fixed roof 

has been added is considered to be an 

internal floating roof. 

Liquid-mounted primary seal means a 

liquid or foam-filled seal mounted in 

continuous contact with the liquid 

between the wall of the storage vessel 

and the floating roof around the entire 

circumference of the storage vessel. 

Maximum true vapor pressure means 

the equilibrium partial pressure exerted 

by the volatile organic compounds (as 

defined in 40 CFR 51.100) in the stored 

VOL at the temperature equal to the 

highest calendar-month average of the 

VOL storage temperature for VOLs 

stored above or below the ambient 

temperature or at the local maximum 

monthly average temperature as 

reported by the National Weather 

Service for VOLs stored at the ambient 


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temperature, as determined using the 

procedures specified in § 60.113c(d). 

Mechanical shoe primary seal means 

a metal sheet (the shoe) held vertically 

against the wall of the storage vessel by 

springs or weighted levels and is 

connected by braces to the floating roof. 

A flexible coated fabric (the envelope) 

spans the annular space between the 

metal sheet and the floating roof. 

Petroleum means the crude oil 

removed from the earth and the oils 

derived from tar sands, shale, and coal. 

Petroleum liquids means petroleum, 

condensate, and any finished or 

intermediate products manufactured in 

a petroleum refinery. 

Pressure release means the emission 

of materials resulting from the system 

pressure being greater than the set 

pressure of the pressure relief device or 

resulting from vacuum breaking device 

failing to close prior to the system 

reaching atmospheric pressure. This 

release can be one release or a series of 

releases over a short time period. 

Pressure relief device means a valve, 

rupture disk, or similar device used 

only to release an unplanned, 

nonroutine discharge of gas from 

process equipment in order to avoid 

safety hazards or equipment damage. 

Devices with low opening pressures 

must be monitored as bypass lines. A 

pressure relief device discharge can 

result from an operator error, a 

malfunction such as a power failure or 

equipment failure, or other unexpected 

cause. Such devices include 

conventional, spring-actuated relief 

valves, balanced bellows relief valves, 

pilot-operated relief valves, rupture 

disks, and breaking, buckling, or 

shearing pin devices. Devices that are 

actuated only by a vacuum are not 

pressure relief devices. If a device has 

both a pressure relief function and a 

vacuum breaking function, such as a 

conservation vent, the portion of the 

conservation vent that acts to relieve 

pressure is considered a pressure relief 

device and the portion of the 

conservation vent that acts to relieve 

vacuum is a vacuum breaking device 

and not a pressure relief device. 

Process tank means a tank that is used 

within a process (including a solvent or 

raw material recovery process) to collect 

material discharged from a feedstock 

storage vessel or equipment within the 

process before the material is transferred 

to other equipment within the process, 

to a product or by-product storage 

vessel, or to a vessel used to store 

recovered solvent or raw material. In 

many process tanks, unit operations 

such as reactions and blending are 

conducted. Other process tanks, such as 

surge control vessels and bottoms 

receivers, however, may not involve 

unit operations. 

Reid vapor pressure means the 

absolute vapor pressure of volatile crude 

oil and volatile nonviscous petroleum 

liquids except liquified petroleum gases. 

Rim-mounted secondary seal means a 

secondary seal mounted on the rim of 

the floating roof of a storage vessel and 

forms continuous seal from the rim of 

the floating roof to the wall of the 

storage vessel. 

Rim seal system means a primary seal 

or a primary and secondary seal, which 

is mounted above the primary seal, and 

is attached to the deck perimeter and 

contacts the storage vessel wall. 

Rim vent means a device consisting of 

a weighted pallet that rests on a valve 

seat. Rim vents are used to release any 

excess pressure or vacuum present in 

the vapor pocket between the seal and 

the rim area of a floating roof storage 

vessel. 

Routed to a process or route to a 

process means the emissions are 

conveyed by hardpiping or a closed vent 

system to any enclosed portion of a 

process unit where the emissions are 

predominately recycled and/or 

consumed in the same manner as a 

material that fulfills the same function 

in the process; and/or transformed by 

chemical reaction into materials that are 

not volatile organic liquids; and/or 

incorporated into a product; and/or 

recovered. 

Storage vessel means each tank, 

reservoir, or container used for the 

storage of volatile organic liquids but 

does not include: 

(1) Frames, housing, auxiliary 

supports, or other components that are 

not directly involved in the containment 

of liquids or vapors; 

(2) Subsurface caverns or porous rock 

reservoirs; or 

(3) Process tanks. 

Vacuum breaker/automatic bleeder 

vent means a device used to equalize the 

pressure of the vapor space across the 

deck of a floating roof as the floating 

roof is either being landed on or floated 

off its roof supports. A vacuum breaker/ 

automatic bleeder vent consists of a well 

with a cover. The cover is designed to 

open as the floating roof is landed. 

Opening of the cover may be 

accomplished by mechanisms such as 

leg actuation or pressure actuation. 

Vacuum breaking device means a 

device on a fixed roof of a storage vessel 

used to prevent mechanical failure of 

the storage vessel due to vacuum 

created as liquids are withdrawn from 

the storage vessel. If a device has both 

a pressure relief function and a vacuum 

breaking function, such as a 

conservation vent, the portion of the 

conservation vent that acts to relieve 

vacuum is considered a vacuum 

breaking device and the portion of the 

conservation vent that acts to relieve 

excess pressure is a pressure relief 

device and not a vacuum breaking 

device. 

Volatile organic liquid (VOL) means 

any organic liquid which can emit 

volatile organic compounds (as defined 

in 40 CFR 51.100) into the atmosphere. 

Waste means any liquid resulting 

from industrial, commercial, mining, or 

agricultural operations, or from 

community activities that is discarded 

or is being accumulated, stored, or 

physically, chemically, or biologically 

treated prior to being discarded or 

recycled. 

§ 60.112c Standard for volatile organic 

compounds (VOC). 

(a) General storage vessel control 

requirements. You must equip and 

operate each storage vessel affected 

facility meeting the thresholds in 

§ 60.110c(c)(1), (c)(2), (d)(1), or (d)(2) as 

specified in paragraphs (a)(1) through 

(4) of this section, as applicable. 

(1) For each storage vessel affected 

facility containing a VOL that, as stored, 

has a maximum true vapor pressure less 

than 11.1 psia (76.6 kPa), you may elect 

to install and operate either an internal 

floating roof meeting the requirements 

in paragraph (b) of this section, an 

external floating roof meeting the 

requirements in paragraph (c) of this 

section, or a closed vent system routed 

to a control device, fuel gas system, or 

process as specified in paragraph (d) of 

this section. 

(2) For each storage vessel affected 

facility containing a VOL that, as stored, 

has a maximum true vapor pressure of 

11.1 psia (76.6 kPa) or more, you must 

install and operate a closed vent system 

routed to a control device, fuel gas 

system, or process as specified in 

paragraph (d) of this section. 

(3) For each storage vessel affected 

facility complying with the closed vent 

system routed to a control device, fuel 

gas system, or process provisions 

specified in paragraph (d) of this section 

regardless of size and for each storage 

vessel with a design capacity greater 

than or equal to 1,000,000 gal (3,790 m3) 

containing a VOL that, as stored, has a 

maximum true vapor pressure equal to 

or greater than 1.5 psia (10.3 kPa), you 

must also comply with the requirements 

in paragraph (e) of this section. 

(4) You must meet the applicable 

testing, monitoring, and inspection 

requirements specified in § 60.113c, 

recordkeeping requirements specified in 

§ 60.115c, and reporting requirements 

specified in § 60.116c. 


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(b) Requirements for an internal 

floating roof. You must equip and 

operate each internal floating roof as 

specified in paragraphs (b)(1) through 

(16) of this section, as applicable. 

(1) The internal floating roof must rest 

or float on the liquid surface (but not 

necessarily in complete contact with it) 

inside a storage vessel that has a fixed 

roof. The internal floating roof must be 

floating on the liquid surface at all 

times, except during initial fill and 

during those intervals when the storage 

vessel is completely emptied or 

subsequently emptied and refilled. 

When the roof is resting on the roof 

supports, the process of filling, 

emptying, or refilling must be 

continuous and must be accomplished 

as rapidly as possible. 

(2) Except as provided in paragraph 

(b)(14) of this section, each internal 

floating roof must be equipped with the 

following closure devices between the 

wall of the storage vessel and the edge 

of the internal floating roof: 

(i) Two seals mounted one above the 

other so that each forms a continuous 

closure that completely covers the space 

between the wall of the storage vessel 

and the edge of the internal floating 

roof. The lower seal is referred to as the 

primary seal, and the upper seal is 

referred to as the secondary seal. 

(ii) The primary seal must be either a 

mechanical shoe seal or a liquidmounted seal. If a mechanical shoe seal 

is used, it must be installed so that one 

end of the shoe extends into the stored 

VOL and the other end extends a 

minimum vertical distance of 6 inches 

(15 centimeters) above the stored 

organic liquid surface. 

(iii) The secondary seal must be rimmounted. 

(3) Each opening in a noncontact 

internal floating roof except for vacuum 

breaker/automatic bleeder vents and the 

rim vents is to provide a projection 

below the liquid surface. 

(4) Vacuum breaker/automatic bleeder 

vents must be equipped with a gasket 

and are to be closed at all times, with 

no visible gaps, when the roof is 

floating. Vacuum breaker/automatic 

bleeder vents must be set to open only 

when the roof is being floated off or is 

being landed on the roof supports. 

(5) Rim vents must be equipped with 

a gasket and must be closed at all times 

with no visible gaps when the roof is 

floating. Rim vents must be set to open 

only when the internal floating roof is 

not floating or when the pressure 

beneath the rim seal system exceeds the 

manufacturer’s recommended setting. 

(6) Each penetration of the internal 

floating roof for the purpose of sampling 

must be a gauge hatch/sample well. 

Except as specified in paragraph (b)(14) 

of this section, the gauge hatch/sample 

well must have a gasketed cover, which 

must be closed at all times, with no 

visible gaps, except when the hatch or 

well must be opened for access. 

(7) Each access hatch and gauge float 

well must be equipped with a cover that 

is gasketed and that is bolted or 

otherwise mechanically secured. The 

cover must be closed and must be bolted 

or otherwise mechanically secured at all 

times, with no visible gaps, except when 

the hatch or well must be opened for 

access. 

(8) Each penetration of the internal 

floating roof that allows for passage of 

a column supporting the fixed roof must 

have a flexible fabric sleeve seal or a 

gasketed sliding cover. 

(9) Each penetration of the internal 

floating roof that allows for passage of 

an unslotted leg ladder or unslotted 

ladder/guidepole combination must 

have a gasketed sliding cover. The cover 

must be closed at all times, with no 

visible gaps, except when the well must 

be opened for access. 

(10) Each slotted guidepole must be 

equipped with one of the controls 

specified in paragraphs (b)(10)(i) 

through (v) of this section. The covers 

must be designed to be closed at all 

times, with no visible gaps, except when 

the cover must be opened for access. 

(i) Gasketed sliding well cover, with 

pole sleeve. The sleeve must extend into 

the stored liquid. 

(ii) Gasketed sliding well cover, with 

pole sleeve and pole wiper. The sleeve 

must extend into the stored liquid. 

(iii) Gasketed sliding well cover, with 

pole float and pole wiper. The wiper or 

seal of the pole float must be at or above 

the height of the pole wiper. 

(iv) Gasketed sliding well cover, with 

pole float, pole sleeve, and pole wiper. 

The sleeve must extend into the stored 

liquid. The wiper or seal of the pole 

float must be at or above the height of 

the pole wiper. 

(v) A flexible device that completely 

encloses the slotted guidepole and 

eliminates the hydrocarbon vapor 

emissions pathway from inside the 

storage vessel through the guidepole 

slots to the outside air; a gasketed 

guidepole cover at the top of the 

guidepole; and a gasketed sliding well 

cover positioned at the top of the 

guidepole well that seals any openings 

between the well cover and the 

guidepole (e.g., pole wiper), any 

openings between the well cover and 

any other objects that pass through the 

well cover, and any other openings in 

the top of the guidepole well. 

(11) Ladder-slotted guidepole 

combination wells must be equipped 

with a gasketed sliding well cover and 

a ladder sleeve. The sliding well cover 

must be designed to be closed at all 

times with no visible gaps, except when 

gauging or sampling. 

(12) Unslotted guidepoles must be 

equipped with one of the controls 

specified in paragraph (b)(12)(i) or (ii) of 

this section. The controls must be 

designed to be closed at all times with 

no visible gaps. 

(i) A gasketed guidepole cover at the 

top of the guidepole; a gasketed sliding 

well cover; and a pole sleeve. The 

guidepole cover must be closed at all 

times, except when required to be 

opened for access. The gasketed sliding 

well cover must seal any openings 

between the well cover and the 

guidepole, any openings between the 

well cover and any other objects that 

pass through the well cover, and any 

other openings in the top of the 

guidepole well. 

(ii) A gasketed guidepole cover at the 

top of the guidepole; a gasketed sliding 

well cover; and a pole wiper. The 

guidepole cover must be closed at all 

times, except when required to be 

opened for access. The gasketed sliding 

well cover must seal any openings 

between the well cover and the 

guidepole (e.g., pole wiper), any 

openings between the well cover and 

any other objects that pass through the 

well cover, and any other openings in 

the top of the guidepole well. 

(13) Except for leg sleeves and stub 

drains, each opening in the internal 

floating roof not specified in paragraphs 

(b)(4) through (12) of this section, must 

be equipped with a cover or lid which 

is to be maintained in a closed position 

at all times (i.e., no visible gap) except 

when the device must be opened for 

access. The cover or lid must be 

equipped with a gasket. 

(14) For each modified storage vessel 

as specified in § 60.110c(d) with an 

existing internal floating roof, you may 

elect to comply with the rim seal system 

requirements in § 60.112b(a)(1)(ii) or 

§ 60.110b(e) instead of the requirements 

in paragraph (b)(2) of this section, and 

you may elect to comply with the gauge 

hatch/sample well requirements in 

§ 60.112b(a)(1)(vii) or § 60.110b(e) 

instead of the requirements in paragraph 

(b)(6) of this section. 

(15) A system equivalent to those 

described in paragraphs (b)(1) though 

(14) of this section, as applicable, as 

provided in § 60.114c. 

(16) Equip, maintain, and operate 

each internal floating roof control 

system to maintain the vapor 

concentration above the floating roof at 

or below 25 percent of the lower 

explosive limit (LEL) on a 5-minute 


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rolling average basis without the use of 

purge gas. This standard may require 

additional controls, such as improved 

seam seals, beyond those specified in 

paragraphs (b)(1) through (15) of this 

section. Compliance with this paragraph 

(b)(16) must be determined using the 

methods in § 60.113c(a)(3). Exceeding 

the LEL is considered an inspection 

failure under § 60.113c(a)(2)(i) and must 

be remedied as such. Any repairs made 

must be confirmed effective through remonitoring of the LEL and meeting the 

limits in this paragraph (b)(16) within 

the timeframes specified in 

§ 60.113c(a)(2)(i). 

(c) Requirements for an external 

floating roof. You must equip and 

operate each external floating roof as 

specified in paragraphs (c)(1) through 

(4) of this section. 

(1) The roof must be floating on the 

liquid at all times (i.e., off the roof 

supports) except during initial fill until 

the roof is lifted off roof supports and 

when the storage vessel is completely 

emptied or subsequently emptied and 

refilled. The process of filling, 

emptying, or refilling when the roof is 

resting on the roof supports must be 

continuous and must be accomplished 

as rapidly as possible. 

(2) Each external floating roof must be 

equipped with a primary and secondary 

rim seal system as specified in 

paragraph (b)(2) of this section, except 

that if a mechanical shoe primary seal 

is used, it must be installed so that one 

end of the shoe extends into the stored 

VOL and the other end extends a 

minimum vertical distance of 24 inches 

(61 centimeters) above the stored 

organic liquid surface. The external 

floating roof also must have welded 

deck seams, and it must have deck 

fitting controls as specified in 

paragraphs (c)(2)(i) through (ix) of this 

section, as applicable. References to an 

internal floating roof in paragraph (b)(2) 

of this section means an external 

floating roof for the purposes of this 

paragraph (c)(2). 

(i) Each opening in an external 

floating roof except for vacuum breaker/ 

automatic bleeder vents and the rim 

vents is to provide a projection below 

the liquid surface. 

(ii) Vacuum breaker/automatic 

bleeder vents must be equipped with a 

gasket and are to be closed at all times, 

with no visible gaps, when the roof is 

floating. Vacuum breaker/automatic 

bleeder vents must be set to open only 

when the roof is being floated off or is 

being landed on the roof supports. 

(iii) Rim vents must be equipped with 

a gasket and must be closed at all times 

with no visible gaps when the roof is 

floating. Rim vents must be set to open 

only when the external floating roof is 

not floating or when the pressure 

beneath the rim seal system exceeds the 

manufacturer’s recommended setting. 

(iv) Each penetration of the external 

floating roof for the purpose of sampling 

must be a gauge hatch/sample well. The 

gauge hatch/sample well must have a 

gasketed cover, which must be closed at 

all times, with no visible gaps, except 

when the hatch or well must be opened 

for access. 

(v) Each access hatch and gauge float 

well must be equipped with a cover that 

is gasketed and that is bolted or 

otherwise mechanically secured. The 

cover must be closed and must be bolted 

or otherwise mechanically secured at all 

times, with no visible gaps, except when 

the hatch or well must be opened for 

access. 

(vi) Except as specified in paragraph 

(c)(3) of this section, if the external 

floating roof does not have a liquidmounted primary seal, all guidepoles 

must be unslotted and must be 

equipped as specified in paragraph 

(b)(12) of this section. 

(vii) Except as specified in paragraph 

(c)(3) of this section, if the external 

floating roof has a liquid-mounted 

primary seal, equip each guidepole as 

specified in paragraphs (c)(2)(vii)(A) 

and (B) of this section. 

(A) Each slotted guidepole must be 

equipped as specified in paragraphs 

(b)(10)(ii) or (iv) of this section. 

(B) Each unslotted guidepole must be 

equipped as specified in paragraph 

(b)(12) of this section. 

(viii) Each emergency roof drain is to 

be provided with a slotted membrane 

fabric cover that covers at least 90 

percent of the area of the opening. 

(ix) Except for leg sleeves, each 

opening in the external floating roof not 

subject to controls specified in 

paragraphs (c)(2)(i) through (viii) of this 

section must be equipped with a cover 

or lid which is to be maintained in a 

closed position at all times (i.e., no 

visible gap), except when the device 

must be opened for access. The cover or 

lid must be equipped with a gasket. 

(3) For each modified storage vessel as 

specified in § 60.110c(d) with an 

existing external floating roof, you may 

elect to comply with any of the 

guidepole controls specified in 

paragraphs (b)(10) and (12) of this 

section regardless of the type of primary 

seal used. 

(4) A system equivalent to those 

described in paragraphs (c)(1) through 

(3) of this section as provided in 

§ 60.114c. 

(d) Requirements for closed vent 

system routed to a control device, fuel 

gas system, or process. You must design, 

install, and operate each affected storage 

vessel with a closed vent system that 

routes to a control device, fuel gas 

system, or process as specified in 

paragraphs (d)(1) through (7) of this 

section. 

(1) The storage vessel must be 

designed and operated to be routed 

through a closed vent system to a 

control device, fuel gas system, or 

process at all times the storage vessel 

contains VOL without venting to the 

atmosphere through either meeting the 

storage vessel design requirements 

specified in paragraph (d)(1)(i) of this 

section or the vapor recovery system 

design requirements specified in 

paragraph (d)(1)(ii) of this section. 

Compliance with this requirement must 

be demonstrated according to paragraph 

(d)(1)(iii) of this section. Any vacuum 

breaking device on the storage vessel 

must close while the storage vessel is 

still under vacuum of at least ¥0.1 

inches of water (¥0.0036 psig or 

¥0.025 kPa gauge). 

(i) The storage vessel must be 

designed to operate at a gauge pressure 

of no less than 1 psi greater than the 

maximum true vapor pressure of the 

stored liquid and any back pressure 

anticipated when the storage vessel is 

filled at its maximum rate without 

venting to the atmosphere. 

(ii) The vapor recovery system must 

be designed and operated to maintain 

the pressure in each storage vessel 

routed to a control device below the 

venting pressure of that storage vessel. 

(iii) You must equip each pressure 

relief device and vacuum breaking 

device on a storage vessel with a 

device(s) or use a monitoring system 

that is capable of meeting the 

requirements in paragraphs (d)(1)(iii)(A) 

through (C) of this section. If all 

emissions from a pressure relief device 

are routed through a closed vent system 

to a control device, process, or fuel gas 

system, then you are not required to 

comply with the requirements of this 

paragraph (d)(1)(iii). 

(A) Identifying the pressure release. 

(B) Recording the time and duration 

of each pressure release. 

(C) Notifying operators immediately 

that a pressure release is occurring. The 

device or monitoring system must be 

either specific to the pressure relief 

device or vacuum breaking device itself 

or must be associated with each storage 

vessel to indicate a pressure release to 

the atmosphere. Examples of these types 

of devices and systems include, but are 

not limited to, a rupture disk indicator, 

magnetic sensor, motion detector on the 

pressure relief valve stem, flow monitor, 

or pressure monitor. 


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83324 Federal Register / Vol. 89, No. 199 / Tuesday, October 15, 2024 / Rules and Regulations 

(2) Except for closed vent systems 

operated and maintained under negative 

pressure, each closed vent system must 

meet the requirements specified in 

paragraphs (d)(2)(i) through (iii) of this 

section. 

(i) The closed vent system must be 

designed to collect all VOC vapors and 

gases discharged from the storage vessel 

and operated with no detectable 

emissions as indicated by an instrument 

reading of less than 500 parts per 

million by volume (ppmv) above 

background, as determined using 

Method 21 of appendix A–7 to this part 

as specified in § 60.113c(c)(2) and (3), 

and as determined by observations for 

visible, audible, and olfactory 

indications of leaks. Visible, audible, 

and olfactory inspections must be 

performed quarterly and Method 21 of 

appendix A–7 instrument monitoring 

must be conducted at least annually. 

(ii) Except for pressure relief devices 

and except for open-ended valves or 

lines that use a cap, blind flange, plug, 

or second valve and follow the 

requirements specified in § 60.482– 

6(a)(2), (b), and (c) or follow 

requirements codified in another 

regulation that are the same as § 60.482– 

6(a)(2), (b), and (c), you must comply 

with the provisions of either paragraph 

(d)(2)(ii)(A) or (B) of this section for 

each closed vent system that contains 

bypass lines that could divert a vent 

stream to the atmosphere. 

(A) Properly install, maintain, and 

operate a flow indicator that is capable 

of taking readings every 15 minutes. 

Install the flow indicator at the entrance 

to any bypass line. 

(B) Secure the bypass line valve in the 

non-diverting position with a car-seal or 

a lock-and-key type configuration. 

(iii) You must equip each pressure 

relief device on a closed vent system 

with a device(s) or use a monitoring 

system that is capable of meeting the 

requirements in paragraphs (d)(2)(iii)(A) 

through (C) of this section. If all releases 

and potential leaks from a pressure 

relief device are routed through a closed 

vent system to a control device, process, 

or fuel gas system, then you are not 

required to comply with the 

requirements of this paragraph 

(d)(2)(iii). 

(A) Identifying the pressure release. 

(B) Recording the time and duration 

of each pressure release. 

(C) Notifying operators immediately 

that a pressure release is occurring. The 

device or monitoring system must be 

either specific to the pressure relief 

device itself or must be associated with 

the process system or piping, sufficient 

to indicate a pressure release to the 

atmosphere. Examples of these types of 

devices and systems include, but are not 

limited to, a rupture disk indicator, 

magnetic sensor, motion detector on the 

pressure relief valve stem, flow monitor, 

or pressure monitor. 

(3) If you route emissions from a 

storage vessel to a control device, the 

control device must be designed and 

operated to reduce inlet VOC emissions 

by 98 percent or greater. If a flare is used 

as the control device or if an enclosed 

combustion device is used for which 

you elect to comply with the flare 

operating limits, you must meet the 

specifications described in paragraph 

(d)(5) of this section. The control device 

must be operated at all times when 

emissions from an affected storage 

vessel are routed to it except as 

provided in paragraph (d)(7) of this 

section. 

(4) A system equivalent to those 

described in paragraphs (d)(1) through 

(3) of this section as provided in 

§ 60.114c. 

(5) If you route from a storage vessel 

to a flare or enclosed combustion device 

for with you elect to comply with these 

flare operating limits, you must meet all 

applicable requirements specified in 40 

CFR 63.670(b) through (g) and (i) 

through (n) except as provided in 

paragraphs (d)(5)(i) through (v) of this 

section. 

(i) For the purpose of this subpart, 

(A) The term ‘‘regulated materials’’ 

refers to ‘‘vapors from a storage vessel 

affected facility’’; 

(B) The term ‘‘pilot flame’’ means 

‘‘pilot flame or flare flame’’; 

(C) The terms ‘‘petroleum refinery’’ 

and ‘‘refinery’’ mean ‘‘storage vessel 

affected facility’’. 

(ii) For visible emissions, use the 

following text instead of 40 CFR 

63.670(c): The owner or operator shall 

operate with no visible emissions, 

except for periods not to exceed a total 

of five (5) minutes during any two (2) 

consecutive hours, when regulated 

material is routed to the flare. You must 

monitor for visible emissions from the 

flare as specified in 

§ 60.113c(c)(1)(iv)(A). 

(iii) The phrase ‘‘and the flare vent gas 

flow rate is less than the smokeless 

design capacity of the flare’’ in 40 CFR 

63.670(d) for flare tip velocity 

requirements does not apply. 

(6) If you route emissions from a 

storage vessel to a fuel gas system or 

process, you must meet the 

requirements in paragraphs (d)(6)(i) 

through (iv) of this section, as 

applicable. 

(i) The fuel gas system or process 

must be operating at all times when 

emissions from an affected storage 

vessel are routed to it. 

(ii) If all emissions are routed to a 

process, the VOL in the emissions must 

meet one or more of the conditions 

specified in paragraphs (d)(6)(ii)(A) 

through (D) of this section and you must 

comply with the compliance 

demonstration requirements in 

paragraph (d)(6)(iii) of this section. 

(A) Recycled and/or consumed in the 

same manner as a material that fulfills 

the same function in that process. 

(B) Transformed by chemical reaction 

into materials that are not regulated 

materials. 

(C) Incorporated into a product. 

(D) Recovered. 

(iii) To demonstrate compliance with 

paragraph (d)(6)(ii) of this section for an 

affected storage vessel, you must 

prepare a design evaluation (or 

engineering assessment) that 

demonstrates the extent to which one or 

more of the conditions specified in 

paragraphs (d)(6)(ii)(A) through (D) of 

this section are being met. 

(iv) If emissions from an affected 

storage vessel are routed to a fuel gas 

system, you must submit the statement 

of connection for fuel gas systems 

specified in § 60.116c(a)(7). 

(7) To the extent practical, routine 

maintenance on the control device 

should be conducted when the storage 

vessel(s) is(are) out of VOL service. If 

you comply with all the provisions in 

paragraphs (d)(7)(i) through (iv) of this 

section, you may conduct routine 

maintenance on a control device while 

one or more storage vessels vented to 

the control device are storing a VOL. 

(i) The storage vessel(s) storing VOL 

must be designed to operate above the 

maximum true vapor pressure of the 

stored VOL according to paragraph 

(d)(1)(i) of this section. 

(ii) The control device must be 

isolated from the storage vessel(s) using 

valves(s), blind flange(s), or similar 

device(s) at the control device or in the 

closed vent system as near as practical 

to the control device. You may purge 

the control device and downstream 

portion of the closed vent system to 

remove potentially explosive vapors and 

create a safe work environment only 

after the control device is isolated from 

the storage vessel(s). 

(iii) You must continue to comply 

with the bypass and pressure relief 

device monitoring requirements in 

paragraphs (d)(1)(iii), (d)(2)(ii), and 

(d)(2)(iii) of this section and their 

associated recordkeeping and reporting 

requirements. If there are multiple 

storage vessels connected to the closed 

vent system with significantly different 

pressure design limits, you must isolate 

individual storage vessels to prevent 

venting during planned maintenance. 


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Federal Register / Vol. 89, No. 199 / Tuesday, October 15, 2024 / Rules and Regulations 83325 

Compliance with this paragraph 

(d)(7)(iii) may limit VOL addition to the 

storage vessel. If VOL is added to the 

storage vessel, there must be an 

approximately equivalent withdrawal of 

VOL such that the liquid level does not 

rise sufficiently to increase the pressure 

in the storage vessel to cause a pressure 

release from the storage vessel or the 

closed vent system. 

(iv) During this routine maintenance 

period the affected storage vessels 

cannot be actively degassed. If the 

storage vessel is to be emptied and 

actively degassed, the planned 

maintenance activity must be conducted 

when the storage vessel is out of VOL 

service. 

(e) Requirements for storage vessel 

degassing. For each storage vessel 

meeting the specifications in paragraph 

(a)(3) of this section, you must meet the 

requirements in paragraphs (e)(1) 

through (3) of this section during 

emptying and degassing of a storage 

vessel until the vapor space 

concentration in the storage vessel is 

less than 10 percent of the LEL or, for 

nonflammable liquids, 5,000 ppmv as 

methane. You must determine the LEL 

or methane concentration using process 

instrumentation or a portable 

measurement device and follow 

procedures for calibration and 

maintenance according to 

manufacturer’s specifications. You must 

check instrument calibration and check 

the instrumental offset response each 

day the instrument is used and prior to 

discontinuing controlled degassing to 

confirm the accuracy of the instrument’s 

readings. 

(1) Remove liquids from the storage 

vessel as much as practicable. 

Chemicals or a diluent such as a 

distillate fuel may be introduced into 

the storage vessel for the purpose of 

reducing vapor concentration before or 

during active degassing. 

(2) Comply with one of the following: 

(i) Reduce total VOC emissions by 

venting emissions through a closed vent 

system to a flare or enclosed combustion 

device for which you elect to comply 

with the flare provisions and meet the 

requirements specified in paragraph 

(d)(5) of this section. 

(ii) Reduce total VOC emissions by 98 

weight percent by venting emissions 

through a closed vent system to any 

combination of non-flare control 

devices. 

(iii) Reduce total VOC emissions by 

routing emissions to a fuel gas system or 

process and meet the requirements 

specified in paragraph (d)(6) of this 

section. 

(3) For floating roof storage vessels, 

the storage vessel may be opened to set 

up equipment (e.g., making connections 

to a temporary control device) for the 

shutdown operations but must not be 

actively degassed during this time 

period. 

§ 60.113c Testing, monitoring, and 

inspection procedures. 

For each storage vessel subject to the 

provision in § 60.112c(a), you must meet 

the requirements of paragraph (a) of this 

section if you installed an internal 

floating roof, paragraph (b) of this 

section if you installed an external 

floating roof, or paragraph (c) of this 

section if you route emissions through 

a closed vent system to a control device, 

fuel gas system, or process. You must 

also meet the applicable requirements of 

paragraph (d) of this section. 

(a) Requirements for an internal 

floating roof. After installing the control 

equipment for an internal floating roof 

to meet the provisions in § 60.112c(b), 

you must meet the requirements 

specified in paragraphs (a)(1) through 

(5) of this section. 

(1) Visually inspect the internal 

floating roof, the primary seal, the 

secondary seal (if one is in service), and 

deck fittings prior to filling the storage 

vessel with VOL. Any of the conditions 

described in paragraphs (a)(1)(i) through 

(iii) of this section constitutes 

inspection failure. You must repair the 

items before filling the storage vessel. 

(i) Holes, tears, or other openings in 

the primary seal, the secondary seal, or 

the seal fabric; 

(ii) Defects in the internal floating 

roof; or 

(iii) A rim seal or deck fitting control 

not meeting the applicable requirements 

in § 60.112c(b)(2) through (13). 

(2) Inspect the internal floating roof as 

specified in paragraph (a)(2)(i) of this 

section at least once every 12 calendar 

months after initial fill, and inspect the 

internal floating roof as specified in 

paragraph (a)(2)(ii) of this section each 

time the storage vessel is emptied and 

degassed, or at a frequency no greater 

than every 120 calendar months, 

whichever occurs first. 

(i) Visually inspect the internal 

floating roof, the primary seal, the 

secondary seal (if one is service), and 

deck fittings, through openings in the 

fixed roof and conduct LEL monitoring. 

Any of the conditions described in 

paragraphs (a)(2)(i)(A) through (F) of 

this section constitutes inspection 

failure. Identification of holes or tears in 

the rim seal is required only for the seal 

that is visible from the top of the storage 

vessel. You must repair the items or 

empty and remove the storage vessel 

from service within 45 days. If a failure 

that is detected during inspections 

required in this paragraph (a)(2)(i) 

cannot be repaired within 45 days and 

if the storage vessel cannot be emptied 

within 45 days, you may request a 30- 

day extension from the Administrator. 

Such a request for an extension must 

document that alternate storage capacity 

is unavailable and specify a schedule of 

actions the company will take that will 

assure that the control equipment will 

be repaired or the storage vessel will be 

emptied as soon as possible. 

(A) Stored liquid on the floating roof; 

(B) The internal floating roof is not 

resting on the surface of the VOL inside 

the storage vessel; 

(C) Holes, tears, or other openings in 

the primary seal, the secondary seal, or 

the seal fabric; 

(D) Defects in the internal floating 

roof; 

(E) A rim seal or deck fitting control 

not meeting the applicable requirements 

in § 60.112c(b)(2) through (13); or 

(F) The concentration measured 

according to paragraph (a)(3) of this 

section exceeds 25 percent of the LEL. 

(ii) Visually inspect the internal 

floating roof, the primary seal, the 

secondary seal (if one is in service), 

gaskets, slotted membranes, and sleeve 

seals (if any). Any of the conditions 

described in paragraphs (a)(2)(ii)(A) 

through (C) of this section constitutes an 

inspection failure. You must repair the 

items as necessary so that none of the 

conditions specified in this paragraph 

(a)(2)(ii) exist before refilling the storage 

vessel with VOL. The inspection may be 

performed entirely from the top side of 

the floating roof, as long as there is 

visual access to all deck fittings and rim 

seal system specified in § 60.112c(b). 

You must repair the items or empty and 

remove the storage vessel from service 

within 45 days. If a failure that is 

detected during inspections required in 

this paragraph (a)(2)(ii) cannot be 

repaired within 45 days and if the 

storage vessel cannot be emptied within 

45 days, you may request a 30-day 

extension from the Administrator. Such 

a request for an extension must 

document that alternate storage capacity 

is unavailable and specify a schedule of 

actions the company will take that will 

assure that the control equipment will 

be repaired or the storage vessel will be 

emptied as soon as possible. 

(A) Defects in the internal floating 

roof; 

(B) Holes, tears, or other openings in 

the primary seal, the secondary seal, or 

the seal fabric; or 

(C) A rim seal or deck fitting control 

not meeting the applicable requirements 

in § 60.112c(b)(2) through (13). 

(3) Compliance with the LEL limit for 

internal floating roof storage vessels at 


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83326 Federal Register / Vol. 89, No. 199 / Tuesday, October 15, 2024 / Rules and Regulations 

§ 60.112c(b)(16) must be determined 

based on the procedures specified in 

paragraphs (a)(3)(i) through (v) of this 

section. If tubing is necessary to obtain 

the measurements, the tubing must be 

non-crimping and made of Teflon or 

other inert material. 

(i) You must conduct LEL monitoring 

as part of the annual inspection 

specified in paragraph (a)(2)(i) of this 

section and at other times upon request 

by the Administrator. If the 

measurement cannot be performed 

during the visual inspection due to 

wind speeds exceeding those specified 

in paragraph (a)(3)(iii)(C) of this section, 

the measurement must be performed 

within 30 days of the visual inspection. 

If there is an exceedance of the LEL 

limit, you must re-monitor in 

accordance with § 60.112c(b)(16) within 

30 days after repair or placing the 

storage vessel back in service. 

(ii) The calibration of the LEL meter 

must be checked per manufacturer 

specifications immediately before and 

after the measurements as specified in 

paragraphs (a)(3)(ii)(A) and (B) of this 

section. If tubing will be used for the 

measurements, the tubing must be 

attached during calibration so that the 

calibration gas travels through the entire 

measurement system. 

(A) Conduct the span check using a 

calibration gas recommended by the 

LEL meter manufacturer. The 

calibration gas must contain a single 

hydrocarbon at a concentration of the 

vapor corresponding to 50 percent of the 

LEL (e.g., 2.50 percent by volume when 

using methane as the calibration gas). 

The vendor must provide a Certificate of 

Analysis for the gas, and the certified 

concentration must be within ±2 percent 

(e.g., 2.45 percent–2.55 percent by 

volume when using methane as the 

calibration gas). The LEL span response 

must be between 49 percent and 51 

percent. If the span check prior to the 

measurements does not meet this 

requirement, the LEL meter must be 

recalibrated or replaced. If the span 

check after the measurements does not 

meet this requirement, the LEL meter 

must be recalibrated or replaced, and 

the measurements must be repeated. 

(B) Check the instrumental offset 

response using a certified compressed 

gas cylinder of zero air or an ambient 

environment that is free of organic 

compounds. The pre-measurement 

instrumental offset response must be 0 

percent LEL. If the LEL meter does not 

meet this requirement, the LEL meter 

must be recalibrated or replaced. 

(iii) Conduct the monitoring 

measurements as specified in 

paragraphs (a)(3)(iii)(A) through (D) of 

this section. 

(A) Measurements of the vapors 

within the internal floating roof storage 

vessel must be collected no more than 

3 feet above the internal floating roof. 

(B) Measurements must be taken for a 

minimum of 20 minutes, logging the 

measurements at least once every 15 

seconds, or until one 5-minute average 

as determined according to paragraph 

(a)(3)(v)(B) of this section exceeds the 

limit specified in § 60.112c(b)(16). 

(C) Measurements shall be taken 

when the wind speed at the top of the 

storage vessel is 5 mph or less to the 

extent practicable, but in no case shall 

measurements be taken when the 

sustained wind speed at top of storage 

vessel is greater than the annual average 

wind speed at the site or 15 mph, 

whichever is less. 

(D) Measurements should be 

conducted when the internal floating 

roof is floating with limited product 

movement (limited filling or emptying 

of the storage vessel). 

(iv) To determine the actual 

concentration of the vapor within the 

storage vessel, the percent of the LEL 

‘‘as the calibration gas’’ must be 

corrected according to one of the 

procedures in paragraph (a)(3)(iv)(A) or 

(B) of this section. Alternatively, if the 

LEL meter used has correction factors 

that can be selected from the meter’s 

program, you may enable this feature to 

automatically apply one of the 

correction factors in paragraph 

(a)(3)(iv)(A) or (B) of this section. 

(A) Multiply the measurement by the 

published vapor correction factor for the 

specific LEL meter, stored VOL, and 

calibration gas used; or 

(B) If there is no published correction 

factor for the specific LEL meter used 

and the vapors of the stored VOL, 

multiply the measurement by the 

published correction factor for butane as 

a surrogate for determining the LEL of 

the vapors of the stored VOL. The 

correction factor must correspond to the 

calibration gas used. 

(v) Use the calculation procedures in 

paragraphs (a)(3)(v)(A) through (C) of 

this section to determine compliance 

with the LEL limit. 

(A) For each minute while 

measurements are being taken, 

determine the 1-minute average reading 

as the arithmetic average of the 

corrected individual measurements 

(taken at least once every 15 seconds) 

during the minute. 

(B) Starting with the end of the fifth 

minute of data, calculate a 5-minute 

rolling average as the arithmetic average 

of the previous five 1-minute readings 

determined under paragraph (a)(3)(v)(A) 

of this section. Determine a new 5- 

minute average reading for every 

subsequent 1-minute reading. 

(C) Each 5-minute rolling average 

must meet the LEL limit specified in 

§ 60.112c(b)(16). 

(4) Notify the Administrator as 

specified in § 60.116c(b) at least 30 days 

prior to the inspection of each storage 

vessel for which an inspection is 

required by paragraph (a)(1) or (a)(2)(ii) 

of this section to afford the 

Administrator the opportunity to have 

an observer present. 

(5) You must equip each affected 

storage vessel that has an internal 

floating roof with an alarm system that 

provides a visual or audible signal that 

alerts the operator when the internal 

floating roof is approaching the landed 

height and that provides a separate 

visual or audible signal to alert the 

operator when the roof has landed. The 

roof is considered landed when the 

floating roof first rests on supports or 

when the vacuum breaker/automatic 

bleeder vent begins to open, whichever 

is first (for example, when using a legactuated vent that triggers the vent prior 

to resting on the roof supports). 

(b) Requirements for an external 

floating roof. After installing the control 

equipment for an external floating roof 

to meet the provisions in § 60.112c(c), 

you must inspect the external floating 

roof according to the specifications in 

paragraphs (b)(1) through (8) of this 

section. 

(1) Determine the gap areas and 

maximum gap widths, between the 

primary seal and the wall of the storage 

vessel and between the secondary seal 

and the wall of the storage vessel 

according to the frequency provided in 

paragraphs (b)(1)(i) and (ii) of this 

section. You must visually inspect all 

roof fittings to ensure that covers are 

closed and gasketed with no visible gaps 

and that there are no tears in sleeves, 

wipers, or similar controls used for a 

given fitting during each measurement 

of gaps as required under this paragraph 

(b)(1). 

(i) Measurements of gaps between the 

storage vessel wall and the primary seal 

(seal gaps) must be performed during 

the hydrostatic testing of the storage 

vessel or within 60 days of the initial fill 

with VOL and at least once every 60 

calendar months thereafter. 

(ii) Measurements of gaps between the 

storage vessel wall and the secondary 

seal must be performed within 60 days 

of the initial fill with VOL and at least 

once every 12 calendar months 

thereafter. 

(iii) If any source ceases to store VOL 

for a period of 12 calendar months or 

more, subsequent introduction of VOL 

into the storage vessel must be 


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Federal Register / Vol. 89, No. 199 / Tuesday, October 15, 2024 / Rules and Regulations 83327 

considered an initial fill for the 

purposes of paragraphs (b)(1)(i) and 

(b)(1)(ii) of this section. 

(2) Determine gap widths and areas in 

the primary and secondary seals 

individually by the following 

procedures: 

(i) Measure seal gaps, if any, at one or 

more floating roof levels when the roof 

is floating off the roof supports. 

(ii) Measure seal gaps around the 

entire circumference of the storage 

vessel in each place where a 0.125-inch 

(0.32-centimeter (cm)) diameter uniform 

probe passes freely (without forcing or 

binding against seal) between the seal 

and the wall of the storage vessel and 

measure the circumferential distance of 

each such location. 

(iii) The total surface area of each gap 

described in paragraph (b)(2)(ii) of this 

section must be determined by using 

probes of various widths to measure 

accurately the actual distance from the 

storage vessel wall to the seal and 

multiplying each such width by its 

respective circumferential distance. 

(3) Add the gap surface area of each 

gap location for the primary seal and the 

secondary seal individually and divide 

the sum for each seal by the nominal 

diameter of the storage vessel and 

compare each ratio to the respective 

standards in paragraph (b)(4) of this 

section. 

(4) Except as provided in paragraph 

(b)(5) of this section, make necessary 

repairs or empty the storage vessel 

within 45 days of identification in any 

inspection failure as specified in 

paragraphs (b)(4)(i) through (iii) of this 

section. 

(i) For primary seals, any deviation of 

the requirements in paragraphs 

(b)(4)(i)(A) through (D) of this section is 

an inspection failure. 

(A) The accumulated area of gaps 

between the storage vessel wall and the 

mechanical shoe or liquid-mounted 

primary seal must not exceed 10 square 

inches (in2) per foot of storage vessel 

diameter (212 square centimeters (cm2) 

per meter of storage vessel diameter). 

(B) The maximum width of any 

portion of any gap must not exceed 1.5 

inches (3.81 cm). 

(C) If a mechanical shoe seal is used, 

one end of the mechanical shoe is to 

extend into the stored liquid, and the 

other end is to extend a minimum 

vertical distance of 2 feet (61 cm) above 

the stored liquid surface. 

(D) There are to be no holes, tears, or 

other openings in the shoe, seal fabric, 

or seal envelope. 

(ii) For secondary seals, any deviation 

of the requirements in paragraphs 

(b)(4)(ii)(A) through (D) of this section is 

an inspection failure. 

(A) The secondary seal is to be 

installed above the primary seal so that 

it completely covers the space between 

the roof edge and the storage vessel wall 

except for allowed gaps as provided in 

paragraphs (b)(4)(ii)(B) and (C) of this 

section. 

(B) The accumulated area of gaps 

between the storage vessel wall and the 

secondary seal must not exceed 1 in2

per foot (21.2 cm2 per meter) of storage 

vessel diameter. 

(C) The maximum width of any 

portion of any gap must not exceed 0.5 

inches (1.27 cm). 

(D) There are to be no holes, tears, or 

other openings in the seal or seal fabric. 

(iii) For roof fittings (e.g., vacuum 

breaker/automatic bleeder vents and rim 

vents, gauge hatch/sample wells, access 

hatches, guidepoles, ladders, and 

emergency roof drains), any deviation of 

the requirements in paragraphs 

(b)(4)(iii)(A) through (D) of this section 

is an inspection failure. 

(A) Each opening in an external 

floating roof except for vacuum breaker/ 

automatic bleeder vents and the rim 

vents provides a projection below the 

liquid surface. 

(B) Vacuum breaker/automatic 

bleeder vents and rim vents are 

equipped with a gasket and are closed 

with no visible gaps when the roof is 

floating. 

(C) The gauge hatch/sample well, 

access hatch, and gauge float must have 

a gasketed cover and closed with no 

visible gaps. 

(D) There are to be no tears or visible 

defects of sleeves, wipers, or fabric 

covers used to control emissions from a 

roof fitting. 

(5) If a failure that is detected as 

specified in paragraph (b)(4) of this 

section cannot be repaired within 45 

days and if the storage vessel cannot be 

emptied within 45 days, you may 

request a 30-day extension from the 

Administrator. Such extension request 

must include a demonstration of 

unavailability of alternate storage 

capacity and a specification of a 

schedule that will assure that the 

control equipment will be repaired or 

the storage vessel will be emptied as 

soon as possible. 

(6) Notify the Administrator, as 

specified in § 60.116c(b)(2), 30 days in 

advance of any gap measurements 

required by paragraph (b)(1) of this 

section to afford the Administrator the 

opportunity to have an observer present. 

(7) Visually inspect the external 

floating roof, primary seal, secondary 

seal, and fittings each time the vessel is 

emptied and degassed. 

(i) If the external floating roof has 

defects, the primary seal has holes, 

tears, or other openings in the seal or 

the seal fabric, the secondary seal has 

holes, tears, or other openings in the 

seal or the seal fabric, covers have 

visible openings or missing or torn 

gaskets, or there are tears or other 

visible defects in flexible covers, 

sleeves, wipers, or other fitting controls, 

you must repair the items as necessary 

so that none of the conditions specified 

in this paragraph (b)(7)(i) exist before 

filling or refilling the storage vessel with 

VOL. 

(ii) For each inspection required by 

paragraph (b)(7) of this section, notify 

the Administrator as specified in 

§ 60.116c(b)(1) at least 30 days prior to 

the inspection of each storage vessel to 

afford the Administrator the 

opportunity to inspect the storage 

vessel. 

(8) You must equip each affected 

storage vessel that has an external 

floating roof with an alarm system that 

provides a visual or audible signal that 

alerts the operator when the external 

floating roof is approaching the landed 

height and that provides a separate 

visual or audible signal to alert the 

operator when the roof has landed. The 

roof is considered landed when the 

floating roof first rests on supports or 

when the vacuum breaker/automatic 

bleeder vent begins to open, whichever 

is first (for example, when using a legactuated vent that triggers the vent prior 

to resting on the roof supports). 

(c) Requirements for closed vent 

systems routed to a control device, fuel 

gas system, or process. For each source 

that is equipped with a closed vent 

system and routes to a control device, 

fuel gas system, or process to meet the 

requirements in § 60.112c(d), you must 

conduct performance testing and 

monitoring of the control device as 

specified in paragraph (c)(1) of this 

section, conduct monitoring and 

inspections of the closed vent system as 

specified in paragraph (c)(2) of this 

section, repair leaks as specified in 

paragraph (c)(3) of this section, and 

develop a monitoring plan as specified 

in paragraph (c)(4) of this section. 

(1) For each control device used to 

meet the requirements in § 60.112c(d), 

you must comply with the requirements 

in paragraphs (c)(1)(i) through (iv) of 

this section, as applicable. 

(i) For each enclosed combustion 

device or flare, you must install, 

calibrate, maintain, and operate a 

backpressure regulator valve calibrated 

to open at the minimum pressure set 

point corresponding to the minimum 

inlet gas flow rate. The set point must 

be consistent with manufacturer 

specifications for minimum flow or 

pressure and must be supported by an 


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engineering evaluation. At least 

annually, you must confirm that the 

backpressure regulator valve set point is 

correct and consistent with the 

engineering evaluation and 

manufacturer specifications and that the 

valve fully closes when not in the open 

position. 

(ii) For each control device other than 

a flare, except as specified in paragraph 

(c)(1)(iii) of this section, you must 

conduct a performance test as specified 

in paragraphs (c)(1)(ii)(A) through (E) of 

this section not later than 180 days after 

becoming subject to § 60.112c(d). You 

must conduct subsequent performance 

tests within 60 calendar months after 

each previous performance test. Submit 

the results of all performance tests 

following the procedures in 

§ 60.116c(e). 

(A) Each performance test must 

demonstrate that the control device 

achieves greater than or equal to the 

required control device performance 

level specified in § 60.112c(d)(3). 

Performance tests must be conducted 

under such conditions as the 

Administrator specifies based on 

representative performance of the 

affected source for the period being 

tested. You may not conduct 

performance tests during periods of 

malfunction. You must record the 

process information that is necessary to 

document operating conditions during 

the test and include in such record an 

explanation to support that such 

conditions represent the entire range of 

normal operation, including operational 

conditions for maximum emissions if 

such emissions are not expected during 

maximum production. You must make 

available to the Administrator such 

records as may be necessary to 

determine the conditions of 

performance tests. 

(B) You must conduct a minimum of 

three test runs. Each test run must be at 

least 1 hour long. 

(C) The following methods in 

appendix A to this part, except as 

provided in § 60.8(b), must be used as 

reference methods to determine 

compliance with the percent reduction 

requirement. 

(1) Method 1 or 1A of appendix A–1 

to this part, as appropriate, for selection 

of the sampling sites. Sampling sites 

must be located at the inlet of the first 

control device and at the outlet of the 

final control device to determine 

compliance with a control device 

percent reduction requirement. 

(2) Method 2, 2A, 2C, or 2D of 

appendix A–1 to this part, as 

appropriate to determine the gas 

volumetric flow rate. 

(3) Method 25A of appendix A–7 to 

this part. Use propane as the calibration 

gas. You must use Method 4 of 

appendix A–3 to this part to convert the 

Method 25A of appendix A–7 results to 

a dry basis. 

(D) You must use the procedures in 

paragraphs (c)(1)(ii)(D)(1) and (2) of this 

section to calculate percent reduction 

efficiency. 

(1) You must compute the mass rate 

of TOC using the following equations: 

Ei = K2CiMpQi

Eo = K2CoMpQo

Equations 1 and 2 to Paragraph 

(c)(1)(ii)(D)(1) 

Where: 

Ei, Eo = Mass rate of TOC at the inlet and 

outlet of the control device, respectively, 

dry basis, kilograms per hour. 

K2 = Constant, 2.494 × 10¥6 (parts per 

million) (gram-mole per standard cubic 

meter) (kilogram/gram) (minute/hour), 

where standard temperature (gram-mole 

per standard cubic meter) is 20 degrees 

Celsius. 

Ci, Co = Concentration of TOC, as propane, 

of the gas stream as measured by Method 

25A of appendix A–7 to this part at the 

inlet and outlet of the control device, 

respectively, dry basis, parts per million 

by volume. 

Mp = Molecular weight of propane, 44.1 

gram/gram-mole. 

Qi, Qo = Flowrate of gas stream at the inlet 

and outlet of the control device, 

respectively, dry standard cubic meter 

per minute. 

(2) You must calculate the percent 

reduction in TOC as follows: 

Equation 3 to Paragraph (c)(1)(ii)(D)(2) 

Where: 

Rcd = Control efficiency of control device, 

percent. 

Ei = Mass rate of TOC at the inlet to the 

control device as calculated under 

paragraph (c)(1)(ii)(D)(1) of this section, 

kilograms per hour. 

Eo = Mass rate of TOC at the outlet of the 

control device, as calculated under 

paragraph (c)(1)(ii)(D)(1) of this section, 

kilograms per hour. 

(E) Except as provided in paragraph 

(c)(1)(ii)(E)(5) of this section, you must 

establish the applicable operating 

parameter limit as specified in 

paragraphs (c)(1)(ii)(E)(1) through (3) of 

this section by calculating the value(s) 

as the arithmetic average of operating 

parameter measurements recorded 

during the three test runs conducted for 

the most recent performance test (the 

average of the test run averages). You 

may operate outside of the established 

operating parameter limit(s) during 

subsequent performance tests in order to 

establish new operating limits. You 

must include the updated operating 

limits with the performance test results 

submitted to the Administrator pursuant 

to § 60.116c(e). Upon establishment of a 

new operating limit, you must thereafter 

operate under the new operating limit. 

You must demonstrate compliance with 

your operating parameter according to 

paragraph (c)(1)(ii)(E)(4) of this section. 

(1) If you use an enclosed combustion 

device, a boiler, or a process heater 

other than those specified in paragraph 

(c)(1)(iii) of this section to control 

emissions, you must set a minimum 

firebox temperature limit during the 

performance test. You must 

continuously monitor the firebox 

temperature with a temperature 

monitoring device installed in the 

firebox or in the ductwork immediately 

downstream from the firebox in a 

position before any substantial heat 

exchange occurs and equipped with a 

continuous recorder that records a 

reading at least once every 15 minutes. 

The monitoring device must have a 

minimum accuracy of ±1 percent of the 

temperature being monitored in degrees 

Celsius, or ±2.5 degrees Celsius, 

whichever value is greater. 

(2) If you use a catalytic incinerator 

other than those specified in paragraph 

(c)(1)(iii) of this section to control 

emissions, you must set a minimum 

temperature limit on the temperature at 

the inlet of the catalyst bed and a 

minimum temperature limit on the 

temperature difference between the 

catalyst bed outlet and inlet. You must 

continuously monitor the temperatures 

with a temperature monitoring device 

equipped with a continuous recorder 

that records a reading at least once every 

15 minutes. The device must be capable 

of monitoring temperature at two 

locations and have a minimum accuracy 

of ±1 percent of the temperature being 

monitored in degrees Celsius, or ±2.5 

degrees Celsius, whichever value is 

greater. You must install one 

temperature sensor in the vent stream at 

the nearest feasible point to the catalyst 

bed inlet, and you must install a second 

temperature sensor in the vent stream at 

the nearest feasible point to the catalyst 

bed outlet. You must install the 

temperature sensor at a location 

representative of the firebox 

temperature. 

(3) If you use a control device other 

than a flare or other than a device listed 

in paragraphs (c)(1)(ii)(E)(1), 

(c)(1)(ii)(E)(2), (c)(1)(ii)(E)(5), or 

(c)(1)(iii) to control emissions, you must 

submit the operating parameters you 

plan to monitor in the performance test 


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notice you provide to the Administrator 

pursuant to § 60.8(d). 

(4) Using the continuous monitoring 

system (CMS) data, you must calculate 

the hourly average of each operating 

parameter. You must demonstrate 

compliance by maintaining the 

operating parameter at or above the 

minimum operating parameter limit on 

a 3-hour rolling average basis. For each 

hour, calculate the hourly value of the 

operating parameter from your CMS. 

Average the three most recent hours of 

data to determine the 3-hour average. 

Determine the 3-hour rolling average by 

recalculating the 3-hour average each 

hour. You must not include periods of 

data collected during monitoring system 

breakdowns, repairs, maintenance 

periods, instrument adjustments, or 

checks to maintain precision and 

accuracy in the operating parameter 

averages. 

(5) For enclosed combustion devices 

for which you elect to comply with the 

flare requirements in § 60.112c(d)(5), 

you must comply with the monitoring 

provisions in paragraph (c)(1)(iv) of this 

section instead of paragraphs 

(c)(1)(ii)(E)(1) through (4) of this section. 

(iii) No performance test is required 

for the control devices identified in 

paragraphs (c)(1)(iii)(A) through (C) of 

this section. 

(A) A boiler or process heater with a 

design heat input capacity of 44 

megawatts (150 million British thermal 

units per hour) or greater. 

(B) A boiler or process heater into 

which the vent stream is introduced 

with the primary fuel. 

(C) A boiler, process heater, or 

incinerator burning hazardous waste, 

which is regulated under 40 CFR part 

63, subpart EEE; part 264; part 265; or 

part 266. 

(iv) For each source that is equipped 

with a closed vent system and a flare to 

meet the requirements in § 60.112c(d) or 

enclosed combustion device electing to 

comply with the requirements in 

§ 60.112c(d)(5), you must conduct 

visible emission observations as 

specified in paragraph (c)(1)(iv)(A) of 

this section and install, operate, and 

maintain CMS for flares following the 

requirements specified in 40 CFR 63.671 

and as specified in paragraphs 

(c)(1)(iv)(B) and (C) of this section. 

(A) If visible emissions are observed 

for more than 1 continuous minute 

during normal duties, visible emissions 

observation using Method 22 of 

appendix A–7 to this part must be 

conducted for 2 hours or until 5- 

minutes of visible emissions are 

observed. 

(B) Substitute ‘‘pilot flame or flare 

flame’’ for each occurrence of ‘‘pilot 

flame.’’ 

(C) As an alternative to determining 

the flare tip velocity rate for each 15- 

minute block to determine compliance 

with the flare tip velocity operating 

limit as specified in 40 CFR 

63.670(k)(2), you may elect to conduct 

a one-time flare tip velocity operating 

limit compliance assessment as 

provided in paragraphs (c)(1)(iv)(C)(1) 

through (4) of this section. If the flare or 

storage vessel control configurations 

change (e.g., flare tip modified or 

additional storage vessel or other 

sources are added for which vapors are 

directed to the flare), you must repeat 

this one-time assessment based on the 

new configuration. 

(1) Determine the unobstructed crosssectional area of the flare tip, in units of 

square feet, as specified in 40 CFR 

63.670(k)(1). 

(2) Determine the maximum flow rate, 

in units of cubic feet per second, based 

on the maximum cumulative loading 

rate for a 15-minute block period 

considering maximum filling rates for 

all storage vessel affected facilities 

controlled by the flare and, if 

applicable, considering the maximum 

release pressure of any other vapors 

directed to the flare. 

(3) Calculate the maximum flare tip 

velocity as the maximum flow rate from 

paragraph (c)(1)(iv)(C)(2) of this section 

divided by the unobstructed crosssectional area of the flare tip from 

paragraph (c)(1)(iv)(C)(1) of this section. 

(4) Demonstrate that the maximum 

flare tip velocity as calculated in 

paragraph (c)(1)(iv)(C)(3) of this section 

is less than 60 feet per second. 

(2) For each closed vent system, you 

must conduct the instrument 

monitoring in paragraphs (c)(2)(i) 

through (iii) of this section. You must 

conduct the initial instrument 

monitoring within 180 days of an 

affected facility being connected to the 

closed vent system. Subsequent 

instrument inspections must be 

conducted within 365 days of the 

previous inspection. Visual, audible, 

and olfactory inspections must be 

conducted quarterly. 

(i) Conduct instrument monitoring 

using the procedures in Method 21 of 

appendix A–7 to this part. The detection 

instrument must meet the performance 

criteria of Method 21 of appendix A–7, 

except that the instrument response 

factor criteria in section 8.1.1 of Method 

21 of appendix A–7 must be for the 

average composition of the fluid and not 

for each individual organic compound 

in the stream. For streams that contain 

nitrogen, air, water, or other inerts that 

are not organic VOC, the representative 

stream response factor must be 

determined on an inert-free basis. The 

instrument reading that defines a leak is 

500 ppmv (as methane). The instrument 

shall be calibrated before use each day 

of its use by the procedures specified in 

Method 21 of appendix A–7. The 

calibration gases in paragraphs 

(c)(2)(i)(A) and (B) of this section must 

be used. The drift assessment specified 

in paragraph (c)(2)(i)(C) of this section 

must be performed at the end of each 

monitoring day. 

(A) Zero air (less than 10 ppm of 

hydrocarbon in air). 

(B) A mixture of methane in air at a 

concentration of approximately 500 

ppmv. 

(C) At the end of each monitoring day, 

check the instrument using the same 

calibration gas that was used to calibrate 

the instrument before use. Follow the 

procedures specified in Method 21 of 

appendix A–7 to this part, section 10.1, 

except do not adjust the meter readout 

to correspond to the calibration gas 

value. If multiple scales are used, record 

the instrument reading for each scale 

used. Divide the arithmetic difference of 

the initial and post-test calibration 

response by the corresponding 

calibration gas value for each scale and 

multiply by 100 to express the 

calibration drift as a percentage. If a 

calibration drift assessment shows a 

negative drift of more than 10 percent, 

then re-monitor all equipment 

monitored since the last calibration with 

instrument readings between the leak 

definition and the leak definition 

multiplied by (100 minus the percent of 

negative drift) divided by 100. If any 

calibration drift assessment shows a 

positive drift of more than 10 percent 

from the initial calibration value, then, 

at the owner/operator’s discretion, all 

equipment with instrument readings 

above the leak definition and below the 

leak definition multiplied by (100 plus 

the percent of positive drift) divided by 

100 monitored since the last calibration 

may be re-monitored. 

(ii) Any parts of the closed vent 

system that are designated as unsafe to 

inspect are exempt from the inspection 

requirements of paragraph (c)(2)(i) of 

this section if the conditions of 

paragraphs (c)(2)(ii)(A) and (B) of this 

section are met. 

(A) The owner or operator determines 

that the equipment is unsafe-to-inspect 

because inspecting personnel would be 

exposed to an imminent or potential 

danger as a consequence of complying 

with paragraph (c)(2)(i) of this section; 

and 

(B) The owner or operator has a 

written plan that requires inspection of 


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the equipment as frequently as practical 

during safe-to-inspect times. Inspection 

is not required more than once 

annually. 

(iii) Any parts of the closed vent 

system that are designated as difficultto-inspect are exempt from the 

inspection requirements of paragraph 

(c)(2)(i) of this section if the provisions 

of paragraphs (c)(2)(iii)(A) and (B) of 

this section apply. 

(A) The owner or operator determines 

that the equipment cannot be inspected 

without elevating the inspecting 

personnel more than 2 meters (7 feet) 

above a support surface; and 

(B) The owner or operator has a 

written plan that requires inspection of 

the equipment at least once every 60 

calendar months. 

(3) Leaks, as indicated by an 

instrument reading greater than 500 

ppmv or emissions detected by visible, 

audible, and olfactory methods, shall be 

repaired as soon as practical following 

the requirements outlined in paragraphs 

(c)(3)(i) and (ii) of this section. 

(i) Except as allowed by paragraph 

(c)(3)(ii) of this section, a first attempt 

at repair shall be made no later than 5 

days after the leak is detected. Repairs 

shall be completed no later than 15 days 

after the leak is detected or at the 

beginning of the next introduction of 

vapors to the system, whichever is later. 

(ii) Delay of repair of a closed vent 

system for which leaks have been 

detected is allowed if repair within 15 

days after a leak is detected is 

technically infeasible or unsafe or if the 

owner or operator determines that 

emissions resulting from immediate 

repair would be greater than the 

emissions likely to result from delay of 

repair. Repair of such equipment shall 

be completed as soon as practical. 

(4) You must develop a monitoring 

plan that covers each CMS used to 

demonstrate continuous compliance for 

your control device as outlined in 

paragraphs (c)(4)(i) and (ii) of this 

section. You must install, calibrate, 

operate, and maintain each CMS in 

accordance with the procedures in your 

monitoring plan. 

(i) For each control device other than 

those specified in paragraph (c)(4)(ii) of 

this section, your monitoring plan must 

contain the information required in 

paragraphs (c)(4)(i)(A) through (G) of 

this section. 

(A) The parameter to be monitored 

and the operating limit for the 

parameter. 

(B) Sampling interface (e.g., 

thermocouple) location such that the 

monitoring system will provide 

representative measurements. 

(C) Description of the monitoring 

system specifications, including the 

detector signal analyzer, data 

acquisition, and calculations. 

(D) Equipment performance checks, 

system accuracy audits, or other audit 

procedures, including the information 

in paragraphs (c)(4)(i)(D)(1) through (4) 

of this section. 

(1) You must conduct the CMS 

equipment performance checks, system 

accuracy audits, or other audit 

procedures specified in the monitoring 

plan at least once every 12 calendar 

months. 

(2) You must also conduct calibration 

checks following any period of more 

than 24 hours throughout which the 

sensor exceeded the manufacturer’s 

specified maximum range unless you 

install a new sensor. 

(3) At least quarterly, you must 

inspect all components for integrity and 

all electrical connections for continuity, 

oxidation, and galvanic corrosion, 

unless you use a redundant CMS. 

(4) Daily checks for indications that 

the system is responding. 

(E) Description of how periods of data 

collected during CMS breakdowns, outof-control periods, repairs, maintenance 

periods, instrument adjustments, or 

checks to maintain precision and 

accuracy, calibration checks, and zero 

(low-level), mid-level (if applicable), 

and high-level adjustments will be 

excluded from operating parameter 

averages. 

(F) Ongoing operation and 

maintenance procedures. 

(G) Ongoing recordkeeping 

procedures. 

(ii) For each flare or enclosed 

combustion device for with you elect to 

comply with the flare provisions in 

§ 60.112c(d)(5), your monitoring plan 

must contain the information required 

by 40 CFR 63.671(b). 

(d) Requirements for determining 

maximum true vapor pressure. For each 

affected storage vessel, you must 

determine the maximum true vapor 

pressure of the stored VOL according to 

the requirements specified in 

paragraphs (d)(1) and (2) of this section. 

For storage vessels operated above or 

below ambient temperatures, the 

maximum true vapor pressure is 

calculated based upon the highest 

expected calendar-month average of the 

storage temperature. For storage vessels 

operated at ambient temperatures, the 

maximum true vapor pressure is 

calculated based upon the maximum 

local monthly average ambient 

temperature as reported by the National 

Weather Service. 

(1) Prior to the initial filling of the 

storage vessel or to the refilling of the 

storage vessel with a new VOL, the 

highest maximum true vapor pressure 

for the range of anticipated liquids to be 

stored, including mixtures for which 

you can define the range of 

concentrations for constituents in the 

mixture or with a known maximum 

Reid vapor pressure, must be 

determined using any one of the 

methods described in paragraphs 

(d)(1)(i) through (iv) of this section. 

(i) As obtained from standard 

reference texts. 

(ii) ASTM D6377–20 (incorporated by 

reference; see § 60.17). Perform the 

method using a vapor-to-liquid ratio of 

4:1, which is expressed in the method 

as VPCR. 

(iii) ASTM D6378–22 (incorporated 

by reference; see § 60.17). Perform the 

method using a vapor-to-liquid ratio of 

4:1. 

(iv) As measured by an appropriate 

method as approved by the 

Administrator. 

(2) For each affected storage vessel 

storing a mixture of indeterminate 

composition or a mixture of unknown 

variable composition, the initial 

determination of the vapor pressure 

required by paragraph (d)(1) of this 

section must be a physical test using 

one of the methods specified in 

paragraphs (d)(1)(ii) through (iv) of this 

section. Additional physical tests using 

one of the methods specified in 

paragraphs (d)(1)(ii) through (iv) of this 

section are required at least once every 

6 calendar months thereafter as long as 

the measured vapor pressure remains 

below the applicable thresholds in 

§ 60.110c(c)(1), (c)(2), (d)(1), or (d)(2). If 

the vapor pressure measured under this 

paragraph (d)(2) exceeds the threshold 

defined in § 60.110c(c)(1), (c)(2), (d)(1), 

or (d)(2) you must meet the 

requirements in § 60.112c and the 

corresponding requirements in 

§§ 60.113c through 60.116c. If the 

storage vessel does not have controls 

meeting the requirements in § 60.112c, 

the storage vessel must be emptied and 

taken out of service until controls 

meeting the requirements in § 60.112c 

can be installed. Upon compliance with 

the provisions in § 60.112c, no 

additional vapor pressure monitoring is 

required. 

§ 60.114c Alternative means of emission 

limitation. 

(a) If, in the Administrator’s 

judgment, an alternative means of 

emission limitation will achieve a 

reduction in emissions at least 

equivalent to the reduction in emissions 

achieved by the applicable requirement 

in § 60.112c, the Administrator will 

publish in the Federal Register a 


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document permitting the use of the 

alternative means for purposes of 

compliance with that requirement. 

(b) Any document under paragraph (a) 

of this section will be published only 

after notice and an opportunity for a 

hearing. 

(c) Any person seeking permission 

under this section must submit to the 

Administrator a written application 

including either: 

(1) An actual emissions test that uses 

a full-sized or scale-model storage vessel 

that accurately collects and measures all 

VOC emissions from a given control 

device and that accurately simulates 

wind and accounts for other emission 

variables such as temperature and 

barometric pressure; or 

(2) An engineering evaluation that the 

Administrator determines is an accurate 

method of determining equivalence. 

(d) The Administrator may condition 

the permission on requirements that 

may be necessary to ensure operation 

and maintenance to achieve the same 

emission reduction as specified in 

§ 60.112c. 

§ 60.115c Recordkeeping requirements. 

(a) Except as otherwise specified in 

paragraphs (b) through (d) of this 

section, you must keep copies of all 

records required by this section and all 

reports required under § 60.116c for at 

least 5 years. 

(b) For each storage vessel affected 

facility as specified in § 60.110c(a), you 

must keep readily accessible records for 

the life of the source showing the 

dimension of the storage vessel and an 

analysis showing the capacity of the 

storage vessel. 

(c) Except as provided in paragraphs 

(c)(1) and (2) of this section, for each 

storage vessel affected facility under this 

subpart, you must maintain a record of 

the VOL currently stored, including a 

description of the VOL stored, the date 

when the VOL was first stored in the 

storage vessel, and the maximum true 

vapor pressure of that VOL. 

(1) For each vessel storing a mixture 

of indeterminate or variable 

composition that meets the 

requirements for vapor pressure 

measurement at least once every 6 

calendar months in § 60.113c(d), you 

must maintain records of each vapor 

pressure measurement for 5 years. 

(2) Each vessel equipped with a 

closed vent system routed to a control 

device, fuel gas system, or process 

meeting the specification of § 60.112c(d) 

is exempt from the requirements of 

paragraph (c) of this section. 

(d) For each storage vessel as 

specified in § 60.112c(a), you must keep 

records as required in paragraphs (d)(1) 

through (5) of this section, as applicable 

depending upon the control equipment 

installed to meet the requirements of 

§ 60.112c. 

(1) After installing control equipment 

for an internal floating roof to meet the 

provisions in § 60.112c(b), you must 

keep the following records. 

(i) Keep a record of each inspection 

performed as required by 

§ 60.113c(a)(1), (a)(2)(i), and (a)(2)(ii). 

Each record must identify the storage 

vessel on which the inspection was 

performed and must contain the date 

the vessel was inspected and the 

observed condition of each component 

of the control equipment (seals, internal 

floating roof, and fittings). 

(ii) For each LEL monitoring event, 

keep records as specified in paragraphs 

(a)(1)(ii)(A) through (I) of this section. 

(A) Date and time of the LEL 

monitoring, and the storage vessel being 

monitored. 

(B) A description of the monitoring 

event (annual monitoring conducted 

concurrent with visual inspection 

required under § 60.113c(a)(2)(i); remonitoring due to high winds during 

annual monitoring; re-monitoring after 

repair attempt; other monitoring event 

as required by the Administrator). 

(C) Wind speed at the top of the 

storage vessel on the date of LEL 

monitoring. 

(D) The LEL meter manufacturer and 

model number used, as well as an 

indication of whether tubing was used 

during the LEL monitoring, and if so, 

the type and length of tubing used. 

(E) Calibration checks conducted 

before and after making the 

measurements, including both the span 

check and instrumental offset. This 

includes the hydrocarbon used as the 

calibration gas, the Certificate of 

Analysis for the calibration gas(es), the 

results of the calibration check, and any 

corrective action for calibration checks 

that do not meet the required response. 

(F) Location of the measurements and 

the location of the floating roof. 

(G) Each measurement (taken at least 

once every 15 seconds). The records 

should indicate whether the recorded 

values were automatically corrected 

using the meter’s programming. If the 

values were not automatically corrected, 

record both the raw (as the calibration 

gas) and corrected measurements, as 

well as the correction factor used. 

(H) Each of the 5-minute rolling 

average readings. 

(I) If the vapor concentration of the 

storage vessel was above 25 percent of 

the LEL on a 5-minute rolling average 

basis, a description of whether the 

floating roof was repaired, replaced, or 

taken out of service. 

(2) After installing control equipment 

for an external floating roof to meet the 

provisions in § 60.112c(c), you must 

keep a record of each inspection and 

gap measurement performed as required 

by § 60.113c(b). The record must 

contain: 

(i) Identification of the storage vessel 

on which the inspection was performed; 

(ii) The date the storage vessel was 

inspected; 

(iii) The type of inspection 

[inspection with gap measurements as 

specified in § 60.113c(b)(1) through (4); 

visual inspection as specified in 

§ 60.113c(b)(7)]; 

(iv) The observed condition of each 

component of the control equipment 

(seals, internal floating roof, and 

fittings); and 

(v) For each inspection with gap 

measurements as specified in 

§ 60.113c(b)(1) through (4): 

(A) The raw data obtained in the 

measurement; and 

(B) The calculations described in 

§ 60.113c(b)(2) and (b)(3). 

(3) After installing a closed vent 

system routed to a control device, fuel 

gas system, or process to comply with 

the provisions in § 60.112c(d), you must 

keep the following records, as well as 

the records in paragraph (d)(4) or (5) of 

this section, as applicable. 

(i) The make and model of the 

backpressure regulator valve, date of 

installation, and inlet flow rating. 

Maintain records of the engineering 

evaluation and manufacturer 

specifications that identify the pressure 

set point corresponding to the minimum 

inlet gas flow rate, the annual 

confirmation that the backpressure 

regulator valve set point is correct and 

consistent with the engineering 

evaluation and manufacturer 

specifications, and the annual 

confirmation that the backpressure 

regulator valve fully closes when not in 

open position. 

(ii) The CMS monitoring plan 

required by § 60.113c(c)(4), if the closed 

vent system is routed to a control 

device. Retain this plan for the life of 

the control equipment. 

(iii) Monitoring for the closed vent 

system conducted under § 60.113c(c)(2), 

including the date of inspection. 

(iv) The written plan(s) required 

under § 60.113c(c)(2)(ii) and (iii) for 

unsafe-to-inspect and difficult-toinspect portions of the closed vent 

system. 

(v) For each leak detected during the 

monitoring conducted under 

§ 60.113c(c)(2) and (3), you must record: 

the date the leak was detected; the 

location of the leak; the method used to 

detect the leak (Method 21 of appendix 


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A–7 to this part or visible, audible, and 

olfactory methods); and the maximum 

concentration reading obtained by 

Method 21 of appendix A–7, if 

applicable. For each repair attempt, you 

must record: the date of each repair 

attempt; the actions taken to repair the 

leak during each repair attempt; and 

date the repair was completed. If the 

repair is delayed, you must record the 

reason for the delay and the date you 

expect to complete the repair. 

(vi) For each bypass line, maintain a 

record of the following, as applicable: 

readings from the flow indicator; each 

inspection of the seal or closure 

mechanism; the date and time of each 

instance when the seal mechanism is 

broken, the bypass line valve position 

has changed, or the key for a lock-andkey type lock has been checked out. 

(vii) For each pressure relief device or 

vacuum breaking device on a storage 

vessel or closed vent system required to 

be monitored according to 

§ 60.112c(d)(1)(iii) or (d)(2)(iii): the 

device type; the monitoring device or 

system used for the device; data from 

the device or system indicating whether 

a pressure release occurred; and the 

date, time, and duration of each 

pressure release, if applicable. 

(4) After installing a closed vent 

system routed to a control device other 

than a flare or enclosed combustion 

device electing to comply with 

§ 60.112c(d), you must keep the 

following records. 

(i) Each performance test. 

(ii) All CMS performance checks, 

audits, maintenance, and repairs. 

(iii) The hourly values recorded by 

the CMS and all 3-hour rolling averages. 

(iv) The periods when the CMS is not 

operational. 

(5) After installing a closed vent 

system routed to a flare to comply with 

§ 60.112c(d) or an enclosed combustion 

device for which you elected to comply 

with § 60.112c(d)(5), you must keep the 

following records. 

(i) Pilot flame or flare flame 

monitoring as specified in paragraphs 

(d)(5)(i)(A) and (B) of this section. 

(A) The output of the monitoring 

device used to detect the presence of a 

pilot flame as required in 40 CFR 

63.670(b). Retain these records for a 

minimum of 2 years. 

(B) Each 15-minute block during 

which there was at least 1 minute that 

no pilot flame was present when VOL 

vapors were routed to the flare. Each 

record must identify the start and end 

time and date of each 15-minute block. 

(ii) Visible emissions observations as 

specified in paragraphs (d)(5)(ii)(A) 

through (B) of this section, as 

applicable. 

(A) If visible emissions observations 

are performed using Method 22 of 

appendix A–7 to this part, the record 

must identify the date, the start and end 

time of the visible emissions 

observation, and the number of minutes 

for which visible emissions were 

observed during the observation. If the 

owner or operator performs visible 

emissions observations more than one 

time during a day, include separate 

records for each visible emissions 

observation performed. 

(B) For each 2-hour period for which 

visible emissions are observed for more 

than 5 minutes in 2 consecutive hours 

but visible emissions observations 

according to Method 22 of appendix A– 

7 to this part were not conducted for the 

full 2-hour period, the record must 

include the date, the start and end time 

of the visible emissions observation, and 

an estimate of the cumulative number of 

minutes in the 2-hour period for which 

emissions were visible based on best 

information available to the owner or 

operator. 

(iii) Each 15-minute block period 

during which operating values are 

outside of the applicable operating 

limits specified in 40 CFR 63.670(d) 

through (f) when vapors from a storage 

vessel affected facility are directed to 

the flare for at least 15-minutes 

identifying each specific operating limit 

that was not met. 

(iv) The 15-minute block average 

cumulative flows for the enclosed 

combustion device vent gas or flare vent 

gas and, if applicable, total steam, 

perimeter assist air, and premix assist 

air specified to be monitored under 40 

CFR 63.670(i), along with the date and 

start and end time for the 15-minute 

block. If multiple monitoring locations 

are used to determine cumulative vent 

gas flow, total steam, perimeter assist 

air, and premix assist air, retain records 

of the 15-minute block average flows for 

each monitoring location for a minimum 

of 2 years, and retain the 15-minute 

block average cumulative flows that are 

used in subsequent calculations for a 

minimum of 5 years. If pressure and 

temperature monitoring is used, retain 

records of the 15-minute block average 

temperature, pressure and molecular 

weight of the flare vent gas, enclosed 

combustion device vent gas, or assist gas 

stream for each measurement location 

used to determine the 15-minute block 

average cumulative flows for a 

minimum of 2 years, and retain the 15- 

minute block average cumulative flows 

that are used in subsequent calculations 

for a minimum of 5 years. 

(v) The flare vent gas or enclosed 

combustion device vent gas 

compositions specified to be monitored 

under 40 CFR 63.670(j). Retain records 

of individual component concentrations 

from each compositional analyses for a 

minimum of 2 years. If an NHVvg

analyzer is used, retain records of the 

15-minute block average values for a 

minimum of 5 years, as well as records 

of quality assurance activities 

conducted on the analyzer and any 

cylinder gas certificates. If you 

demonstrate your gas streams have 

consistent composition using the 

provisions in 40 CFR 63.670(j)(6), retain 

records of the current application for 

which you are using for as long as you 

use the fixed NHVvg as determined 

using the provisions in 40 CFR 

63.670(j)(6). 

(vi) Each 15-minute block average 

operating parameter calculated 

following the methods specified in 40 

CFR 63.670(k) through (n), as 

applicable. 

(vii) All periods during which you did 

not perform monitoring according to the 

procedures in 40 CFR 63.670(g), (i), and 

(j) as applicable. Note the start date, 

start time, and duration in minutes for 

each period. 

(viii) If you conduct a one-time flare 

tip velocity operating limit compliance 

assessment according to 

§ 60.113c(c)(1)(iv)(C), a copy of the 

assessment, including all calculations 

for as long as you use this compliance 

method. 

(ix) For each parameter monitored 

using a CMS, retain the records 

specified in paragraphs (d)(5)(ix)(A) 

through (C) of this section, as 

applicable: 

(A) For each deviation, record the 

start date and time, duration, cause, and 

corrective action taken. 

(B) For each period when there is a 

CMS outage or the CMS is out of 

control, record the start date and time, 

duration, cause, and corrective action 

taken. 

(C) Each inspection or calibration of 

the CMS including a unique identifier, 

make, and model number of the CMS, 

and date of calibration check. 

(x) For an enclosed combustion 

device for which you elected to comply 

with § 60.112c(d)(5), you must also keep 

a copy of each performance test. 

(e) If you are required to meet the 

degassing requirements in 

§ 60.112c(a)(3), you must maintain 

records necessary to demonstrate 

compliance with the requirements in 

§ 60.112c(e) including, if appropriate, 

records of existing standard site 

procedures used to empty and degas 

(deinventory) equipment for safety 

purposes. 


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§ 60.116c Reporting requirements. 

(a) Initial notification requirements. 

You must submit initial notifications to 

the Administrator within 60 days after 

October 15, 2024 or within 60 days after 

becoming an affected storage vessel, 

whichever is later. Once the report 

template for this subpart has been 

available on the Compliance and 

Emissions Data Reporting Interface 

(CEDRI) website (https://www.epa.gov/ 

electronic-reporting-air-emissions/cedri) 

for 1 year, you must submit all 

subsequent initial notifications using 

the appropriate electronic report 

template on the CEDRI website for this 

subpart and following the procedure 

specified in paragraph (f) of this section. 

The date report templates become 

available will be listed on the CEDRI 

website. For each storage vessel affected 

facility subject to the standards in 

§ 60.112c, include the following 

information in the initial notification: 

(1) The following general facility 

information: 

(i) Facility name; 

(ii) Facility physical address, 

including city, county, State, and zip 

code; 

(iii) Latitude and longitude of 

facility’s physical location. Coordinates 

must be in decimal degrees with at least 

five decimal places; and 

(iv) The following information for the 

facility contact person: 

(A) Name; 

(B) Mailing address, including city, 

county, State, and zip code; 

(C) Telephone number; and 

(D) Email address. 

(2) Identification of the storage 

vessel(s) subject to this subpart. 

(3) Capacity (in gallons) of each 

storage vessel. 

(4) Maximum true vapor pressure of 

the liquid stored (in psia) in each 

storage vessel. 

(5) Indication of the standards for 

which the storage vessel complies 

[§§ 60.112c(b); 60.112c(c); 60.112c(d); 

60.112c(e)]. 

(6) If you route emissions to a control 

device, specify the design of the storage 

vessel and closed vent system (i.e., 

storage vessel designed according to 

§ 60.112c(d)(1)(i); or closed vent system 

designed according to 

§ 60.112c(d)(1)(ii)), the type of control 

device (i.e., enclosed combustion device 

complying with temperature operating 

limit; enclosed combustion device 

electing to comply with § 60.112c(d)(5); 

process heater or boiler; catalytic 

incinerator; flare, or other control device 

(specify)). 

(7) If you route emissions to a process, 

submit the information specified in 

§ 60.112c(d)(6)(ii) and (iii). 

(8) If you route emissions to a fuel gas 

system, as specified in 

§ 60.112c(d)(6)(iv), submit a statement 

that the emission stream is connected to 

the fuel gas system. 

(b) Other notifications. Submit 

notifications for filling and refilling an 

affected storage vessel and for 

conducting gap measurements as 

specified in paragraphs (b)(1) and (2) of 

this section. 

(1) As specified in § 60.113c(a)(4) and 

(b)(7)(ii), you must notify the 

Administrator at least 30 days prior to 

inspection of each storage vessel for 

which an inspection is required by 

§ 60.113c(a)(1), (a)(2)(ii) or (b)(7) to 

afford the Administrator the 

opportunity to have an observer present. 

Submit the notification using CEDRI as 

specified in paragraph (f) of this section. 

If the inspection required by 

§ 60.113c(a)(2)(ii) or (b)(7) is not 

planned and you could not have known 

about the inspection 30 days in advance 

of refilling the storage vessel, you must 

notify the Administrator at least 7 days 

prior to the refilling of the storage 

vessel. Notification shall be made by 

telephone immediately followed by 

written documentation using CEDRI 

demonstrating why the inspection was 

unplanned. 

(2) As specified in § 60.113c(b)(6), you 

must notify the Administrator 30 days 

in advance of any gap measurements 

required by § 60.113c(b)(1) to afford the 

Administrator the opportunity to have 

an observer present. Submit the 

notification using CEDRI as specified in 

paragraph (f) of this section. If the 

inspection required by § 60.113c(b)(1) is 

not planned and you could not have 

known about the inspection 30 days in 

advance of the gap measurement, you 

must notify the Administrator at least 7 

days prior to the conducting the gap 

measurement. Notification must be 

made by telephone immediately 

followed by written documentation 

using CEDRI demonstrating why the gap 

measurement was unplanned. 

(c) Reporting requirements for 

semiannual report. You must submit to 

the Administrator semiannual reports 

with the applicable information in 

paragraphs (c)(1) through (12) of this 

section by the dates specified in 

paragraph (d) of this section. For this 

subpart, the semiannual reports 

supersede the excess emissions and 

monitoring systems performance report 

and/or summary report form required 

under § 60.7. Once the report template 

for this subpart has been available on 

the CEDRI website (https://

www.epa.gov/electronic-reporting-airemissions/cedri) for 1 year, you must 

submit all subsequent reports using the 

appropriate electronic report template 

on the CEDRI website for this subpart 

and following the procedure specified 

in paragraph (f) of this section. The date 

report templates become available will 

be listed on the CEDRI website. Unless 

the Administrator or delegated State 

agency or other authority has approved 

a different schedule for submission of 

reports, the report must be submitted by 

the deadline specified in this subpart, 

regardless of the method in which the 

report is submitted. 

(1) Report the following general 

facility information: 

(i) Facility name; 

(ii) Facility physical address, 

including city, county, and State; 

(iii) Latitude and longitude of 

facility’s physical location. Coordinates 

must be in decimal degrees with at least 

five decimal places; 

(iv) The following information for the 

facility contact person: 

(A) Name; 

(B) Mailing address; 

(C) Telephone number; and 

(D) Email address. 

(v) Date of report and beginning and 

ending dates of the reporting period. 

You are no longer required to provide 

the date of report when the report is 

submitted via CEDRI; and 

(vi) Statement by a responsible 

official, with that official’s name, title, 

and signature, certifying the truth, 

accuracy, and completeness of the 

content of the report. If your report is 

submitted via CEDRI, the certifier’s 

electronic signature during the 

submission process replaces the 

requirement in this paragraph (c)(1)(vi). 

(2) For storage vessels complying with 

the provisions of § 60.112c(b) or (c): 

(i) Identification of the storage vessel 

and an indication of whether you 

comply with § 60.112c(b) or (c). 

(ii) An indication whether the storage 

vessel was inspected during the 

reporting period, and if so, the date and 

type of each inspection conducted 

during the reporting period [the type of 

inspection shall be selected from the 

following list: initial IFR inspection 

according to § 60.113c(a)(1), IFR visual 

inspection from fixed roof according to 

§ 60.113c(a)(2)(i), combined IFR visual 

inspection with LEL monitoring 

according to § 60.113c(a)(2)(i) and (3), 

internal IFR inspection according to 

§ 60.113c(a)(2)(ii), IFR LEL monitoring 

according to § 60.113c(a)(3), EFR gap 

measurements according to 

§ 60.113c(b)(1) through (4), or visual 

EFR inspection according to 

§ 60.113c(b)(7)]. 

(iii) For storage vessels complying 

with the provisions of § 60.112c(b) that 

were not inspected according to 


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§ 60.113c(a)(2)(ii) during the reporting 

period, report the last date the storage 

vessel was inspected according to the 

provisions in § 60.113c(a)(2)(ii). 

(3) For each failure of a visual 

inspection required under 

§ 60.113c(a)(2)(i), report the information 

in paragraphs (c)(3)(i) through (iii) of 

this section. For each failure of LEL 

monitoring required under 

§ 60.113c(a)(3), report the information in 

paragraphs (c)(3)(i) through (iv) of this 

section. 

(i) Identification of the storage vessel; 

(ii) The date of the inspection; 

(iii) The nature of the defects; and 

(iv) The following information 

regarding the LEL monitoring 

conducted: 

(A) Date and start and end times of 

the LEL monitoring conducted. 

(B) Wind speed in miles per hour at 

the top of the storage vessel on the date 

of LEL monitoring. 

(C) The highest 5-minute rolling 

average reading during the monitoring 

event. 

(D) If re-monitoring was required due 

to excessive wind or repair during the 

visual inspection, report the information 

in paragraphs (b)(3)(iv)(A) through (C) of 

this section for the re-monitoring event. 

(E) Whether the floating roof was 

repaired, replaced, or taken out of VOL 

service. If the storage vessel was taken 

out of VOL service, report the date the 

storage vessel was emptied. If the 

floating roof was replaced or repaired, 

report the nature of and date the repair 

was made and the information in 

paragraphs (b)(3)(iv)(A) through (C) of 

this section for each re-monitoring 

conducted to confirm the repair. 

(4) For each inspection required by 

§ 60.113c(a)(2)(ii) that finds holes or 

tears in the seal or seal fabric, defects in 

the internal floating roof, or other 

control equipment defects listed in 

§ 60.113c(a)(2)(ii), report: 

(i) Identification of the storage vessel 

and date of inspection; 

(ii) The reason it did not meet the 

specifications of § 60.112c(b) or 

§ 60.113c(a)(2)(ii); 

(iii) A description of each repair 

made; and 

(iv) Date of repair. 

(5) For each inspection required 

under § 60.113c(b)(1), report the 

following information: 

(i) Identification of the storage vessel 

and the date of the inspection; 

(ii) The accumulated area of gaps 

between the storage vessel wall and the 

primary seal (in square inches per foot 

of storage vessel diameter); 

(iii) The maximum width of any 

portion of any gap in the primary seal 

(in inches); 

(iv) The accumulated area of gaps 

between the storage vessel wall and the 

secondary seal (in square inches per foot 

of storage vessel diameter); 

(v) The maximum width of any 

portion of any gap in the secondary seal 

(in inches); and 

(vi) An indication whether there was 

an inspection failure. If there was an 

inspection failure, also include the 

following information in the report: 

(A) An indication of the type of 

deviation(s) [indicating all that apply 

from: §§ 60.113c(b)(4)(i)(A), 

60.113c(b)(4)(i)(B), 60.113c(b)(4)(i)(C), 

60.113c(b)(4)(i)(D), 60.113c(b)(4)(ii)(A), 

60.113c(b)(4)(ii)(B), 60.113c(b)(4)(ii)(C), 

60.113c(b)(4)(ii)(D), 60.113c(b)(4)(iii)(A), 

60.113c(b)(4)(iii)(B), 

60.113c(b)(4)(iii)(C), 

60.113c(b)(4)(iii)(D)]; and 

(B) The date the storage vessel was 

emptied or the repairs made and date of 

repair. 

(6) For each inspection required by 

§ 60.113c(b)(7) that finds defects as 

listed in § 60.113c(b)(7)(i), report: 

(i) Identification of the storage vessel 

and date of inspection; 

(ii) The reason it did not meet the 

specifications of § 60.112c(c) or 

§ 60.113c(b)(7); 

(iii) A description of each repair 

made; and 

(iv) Date of repair. 

(7) For each landing of an internal 

floating roof or an external floating roof 

that triggers an alarm required by 

§ 60.113c(a)(5) or (b)(8), report: 

(i) Identification of the storage vessel; 

(ii) Date the roof was landed; and 

(iii) Indication of whether the roof 

landed because the storage vessel was 

being emptied. 

(8) After installing a closed vent 

system that routes to a control device, 

fuel gas system, or process to comply 

with § 60.112c, report the following, as 

well as the information in paragraphs 

(c)(9) or (10) of this section, as 

applicable: 

(i) Results of annual inspections that 

indicate a backpressure regulator valve 

is not set correctly or does not fully 

close when not in the open position. 

Include the date and time of the 

inspection, the type of deviation, the 

corrective action taken, and the date and 

time when the backpressure regulator 

valve is set correctly, repaired, or 

replaced. 

(ii) For each inspection conducted 

under § 60.113c(c)(2), identification of 

the closed vent system, the date of 

inspection, the type of inspection 

(Method 21 of appendix A–7 to this part 

or visible, audible, and olfactory 

methods) and summary result of the 

inspection (no leaks detected or leaks 

were detected). For each leak detected, 

provide an identification of the part of 

the closed vent system associated with 

the leak, the date of the first attempt at 

repair, and the date of successful repair 

or anticipated repair if the repair is 

delayed. 

(iii) The start date and time, duration 

in hours, and an estimate of the mass 

quantity in pounds of VOL released for 

times when flow is detected or 

emissions are diverted from the control 

device through a bypass line while a 

storage vessel affected facility vented to 

the closed vent system contains VOL or 

is being degassed. 

(9) After installing a closed vent 

system and control device to comply 

with § 60.112c other than a flare or an 

enclosed combustion device electing to 

comply with § 60.112c(d)(5), report: 

(i) For each instance when the CMS 

measured 3-hour rolling averages below 

the established operating limit: 

(A) The date and start time of the 

deviation; 

(B) The duration of the deviation in 

hours; 

(C) The lowest 3-hour rolling average 

operating parameter reading during the 

period of the deviation; 

(D) A unique identifier for the CMS; 

(E) The make, model number, and 

date of last calibration check of the 

CMS; and 

(F) The cause of the deviation and the 

corrective action taken. 

(ii) For all instances when the CMS 

was inoperative: 

(A) The date and start time of the 

deviation; 

(B) The duration of the deviation in 

hours; 

(C) A unique identifier for the CMS; 

(D) The make, model number, and 

date of last calibration check of the 

CMS; and 

(E) The cause of the deviation and the 

corrective action taken. 

(10) After installing a closed vent 

system and a flare to comply with 

§ 60.112c or an enclosed combustion 

device electing to comply with 

§ 60.112c(d)(5), report: 

(i) The date and start and end times 

for each of the following instances: 

(A) Each 15-minute block during 

which there was at least 1 minute when 

storage vessel vapors were routed to the 

flare and no pilot flame or flare flame 

was present. 

(B) Each period of 2 consecutive 

hours during which visible emissions 

exceeded a total of 5 minutes. 

Additionally, report the number of 

minutes for which visible emissions 

were observed during the observation or 

an estimate of the cumulative number of 

minutes in the 2-hour period for which 


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emissions were visible based on best 

information available to the owner or 

operator. 

(C) Each 15-minute period for which 

the applicable operating limits specified 

in 40 CFR 63.670(d) through (f) were not 

met. You must identify the specific 

operating limit that was not met and 

report the value of the net heating value 

operating parameter(s) during the 

deviation determined following the 

methods in 40 CFR 63.670(k) through 

(n) as applicable. 

(ii) The start date, start time, and 

duration in minutes for each period 

when storage vessel vapors were routed 

to the flare or enclosed combustion 

device and the applicable monitoring 

was not performed. 

(iii) For each instance reported under 

paragraphs (c)(10)(i) and (ii) of this 

section that involves CMS, report the 

following information: 

(A) A unique identifier for the CMS; 

(B) The make, model number, and 

date of last calibration check of the 

CMS; and 

(C) The cause of the deviation or 

downtime and the corrective action 

taken. 

(11) For pressure relief devices on a 

storage vessel or closed vent system 

subject to § 60.112c(d)(1)(iii) or 

(d)(2)(iii), report each pressure release to 

the atmosphere, including pressure 

relief device identification name or 

number, the start date, start time, and 

duration (in minutes) of the pressure 

release; and an estimate of the mass 

quantity in pounds of VOL released. 

(12) For vacuum breaking devices on 

a storage vessel subject to § 60.112c(d) 

and (d)(1)(iii), report the following 

information for each time the vacuum 

breaking device failed to close prior to 

the storage vessel reaching atmospheric 

pressure: identification name or number 

of vacuum breaking device; the start 

date, start time, and duration (in 

minutes) of the pressure release; and an 

estimate of the mass quantity in pounds 

of VOL released. 

(d) Timeframe for semiannual report 

submissions. (1) The first semiannual 

report will cover the period starting 

with the date the source first becomes 

an affected facility subject to this 

subpart and ending June 30 or December 

31, whichever date is earlier. For 

example, if the source becomes an 

affected facility on April 15, the first 

semiannual report would cover the 

period from April 15 to June 30. The 

first semiannual report must be 

submitted on or before the last day of 

the month 2 months after the last date 

covered by the semiannual report. In 

this example, the first semiannual report 

would be due August 31. 

(2) Subsequent semiannual reports 

will cover subsequent 6 calendar month 

periods (January 1 through June 30 or 

July 1 through December 31, as 

applicable) with each report due on or 

before the last day of the month 2 

months after the last date covered by the 

semiannual report (August 31 or 

February 28 or 29, as applicable). 

(3) For each affected facility that is 

subject to permitting regulations 

pursuant to 40 CFR parts 70 or 71, if the 

delegated authority has established 

dates for submitting semiannual reports 

pursuant to 40 CFR 70.6(a)(3)(iii)(A) or 

71.6(a)(3)(iii)(A), you may submit the 

first and subsequent semiannual reports 

according to the dates the delegated 

authority has established instead of the 

dates in paragraphs (d)(1) and (2) of this 

section. 

(e) Reporting requirements for 

performance tests. Within 60 days after 

the date of completing each 

performance test, you must submit the 

results following the procedures 

specified in paragraph (f) of this section. 

Data collected using test methods that 

are supported by the U.S. 

Environmental Protection Agency (EPA) 

Electronic Reporting Tool (ERT) as 

listed on the EPA’s ERT website 

(https://www.epa.gov/electronicreporting-air-emissions/electronicreporting-tool-ert) at the time of the test 

must be submitted in a file format 

generated using the EPA’s ERT. 

Alternatively, you may submit an 

electronic file consistent with the 

extensible markup language (XML) 

schema listed on the EPA’s ERT 

website. Data collected using test 

methods that are not supported by the 

EPA’s ERT as listed on the EPA’s ERT 

website at the time of the test must be 

included as an attachment in the ERT or 

an alternate electronic file. 

(f) Requirements for electronically 

submitting reports. If you are required to 

submit notifications or reports following 

the procedures specified in this 

paragraph (f), you must submit 

notifications or reports to the EPA via 

CEDRI, which can be accessed through 

the EPA’s Central Data Exchange (CDX) 

(https://cdx.epa.gov/). The EPA will 

make all the information submitted 

through CEDRI available to the public 

without further notice to you. Do not 

use CEDRI to submit information you 

claim as confidential business 

information (CBI). Although we do not 

expect persons to assert a claim of CBI, 

if you wish to assert a CBI claim for 

some of the information in the report, 

you must submit a complete file in the 

format specified in this subpart, 

including information claimed to be 

CBI, to the EPA following the 

procedures in paragraphs (f)(1) and (2) 

of this section. Clearly mark the part or 

all of the information that you claim to 

be CBI. Information not marked as CBI 

may be authorized for public release 

without prior notice. Information 

marked as CBI will not be disclosed 

except in accordance with procedures 

set forth in 40 CFR part 2. All CBI 

claims must be asserted at the time of 

submission. Anything submitted using 

CEDRI cannot later be claimed CBI. 

Furthermore, under CAA section 114(c), 

emissions data are not entitled to 

confidential treatment, and the EPA is 

required to make emissions data 

available to the public. Thus, emissions 

data will not be protected as CBI and 

will be made publicly available. You 

must submit the same file submitted to 

the CBI office with the CBI omitted to 

the EPA via the EPA’s CDX as described 

earlier in this paragraph (f). 

(1) The preferred method to receive 

CBI is for it to be transmitted 

electronically using email attachments, 

File Transfer Protocol, or other online 

file sharing services. Electronic 

submissions must be transmitted 

directly to the OAQPS CBI Office at the 

email address oaqpscbi@epa.gov, and as 

described above, should include clear 

CBI markings. ERT files should be 

flagged to the attention of the 

Measurement Policy Group Leader and 

all other files should be flagged to the 

attention of the NSPS Kc Rule Lead. If 

assistance is needed with submitting 

large electronic files that exceed the file 

size limit for email attachments, and if 

you do not have your own file sharing 

service, please email oaqpscbi@epa.gov 

to request a file transfer link. 

(2) If you cannot transmit the file 

electronically, you may send CBI 

information through the postal service 

to the following address: U.S. EPA, 

Attn: OAQPS Document Control Officer, 

Mail Drop: C404–02, 109 T.W. 

Alexander Drive, P.O. Box 12055, RTP, 

NC 27711. ERT files should be sent to 

the secondary attention of the 

Measurement Policy Group Leader and 

all other files should be sent to the 

secondary attention of the NSPS Kc 

Rule Lead. The mailed CBI material 

should be double wrapped and clearly 

marked. Any CBI markings should not 

show through the outer envelope. 

(g) Claims of EPA system outage. If 

you are required to electronically 

submit a report through CEDRI in the 

EPA’s CDX, you may assert a claim of 

EPA system outage for failure to timely 

comply with that reporting requirement. 

To assert a claim of EPA system outage, 

you must meet the requirements 

outlined in paragraphs (g)(1) through (7) 

of this section. 


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83336 Federal Register / Vol. 89, No. 199 / Tuesday, October 15, 2024 / Rules and Regulations 

(1) You must have been or will be 

precluded from accessing CEDRI and 

submitting a required report within the 

time prescribed due to an outage of 

either the EPA’s CEDRI or CDX systems. 

(2) The outage must have occurred 

within the period of time beginning 5 

business days prior to the date that the 

submission is due. 

(3) The outage may be planned or 

unplanned. 

(4) You must submit notification to 

the Administrator in writing as soon as 

possible following the date you first 

knew, or through due diligence should 

have known, that the event may cause 

or has caused a delay in reporting. 

(5) You must provide to the 

Administrator a written description 

identifying: 

(i) The date(s) and time(s) when CDX 

or CEDRI was accessed and the system 

was unavailable; 

(ii) A rationale for attributing the 

delay in reporting beyond the regulatory 

deadline to EPA system outage; 

(iii) A description of measures taken 

or to be taken to minimize the delay in 

reporting; and 

(iv) The date by which you propose to 

report, or if you have already met the 

reporting requirement at the time of the 

notification, the date you reported. 

(6) The decision to accept the claim 

of EPA system outage and allow an 

extension to the reporting deadline is 

solely within the discretion of the 

Administrator. 

(7) In any circumstance, the report 

must be submitted electronically as 

soon as possible after the outage is 

resolved. 

(h) Claims of force majeure. If you are 

required to electronically submit a 

report through CEDRI in the EPA’s CDX, 

you may assert a claim of force majeure 

for failure to timely comply with that 

reporting requirement. To assert a claim 

of force majeure, you must meet the 

requirements outlined in paragraphs 

(h)(1) through (5) of this section. 

(1) You may submit a claim if a force 

majeure event is about to occur, occurs, 

or has occurred or there are lingering 

effects from such an event within the 

period of time beginning 5 business 

days prior to the date the submission is 

due. For the purposes of this section, a 

force majeure event is defined as an 

event that will be or has been caused by 

circumstances beyond the control of the 

affected facility, its contractors, or any 

entity controlled by the affected facility 

that prevents you from complying with 

the requirement to submit a report 

electronically within the time period 

prescribed. Examples of such events are 

acts of nature (e.g., hurricanes, 

earthquakes, or floods), acts of war or 

terrorism, or equipment failure or safety 

hazard beyond the control of the 

affected facility (e.g., large scale power 

outage). 

(2) You must submit notification to 

the Administrator in writing as soon as 

possible following the date you first 

knew, or through due diligence should 

have known, that the event may cause 

or has caused a delay in reporting. 

(3) You must provide to the 

Administrator: 

(i) A written description of the force 

majeure event; 

(ii) A rationale for attributing the 

delay in reporting beyond the regulatory 

deadline to the force majeure event; 

(iii) A description of measures taken 

or to be taken to minimize the delay in 

reporting; and 

(iv) The date by which you propose to 

report, or if you have already met the 

reporting requirement at the time of the 

notification, the date you reported. 

(4) The decision to accept the claim 

of force majeure and allow an extension 

to the reporting deadline is solely 

within the discretion of the 

Administrator. 

(5) In any circumstance, the reporting 

must occur as soon as possible after the 

force majeure event occurs. 

§ 60.117c Delegation of authority. 

(a) In delegating implementation and 

enforcement authority of this subpart to 

a State, local, or Tribal agency under 

section 111(c) of the Act, the authorities 

contained in paragraph (b) of this 

section shall be retained by the 

Administrator of U.S. EPA and cannot 

be transferred to the State, local, or 

Tribal agency. 

(b) Authorities which will not be 

delegated to State, local, or Tribal 

agencies: §§ 60.113c(d)(1)(iv) and 

60.114c and approval of an alternative 

to any electronic reporting to the EPA 

required by this subpart. 

[FR Doc. 2024–22823 Filed 10–11–24; 8:45 am] 

BILLING CODE 6560–50–P 


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