Approval and Promulgation of Implementation Plans; Colorado; Revisions to Regulation Number 7; Aerospace, Oil and Gas, and Other RACT Requirements for 2008 8-Hour Ozone Standard for the Denver Metro/North Front Range Nonattainment Area

Published date22 June 2021
Citation86 FR 32656
Record Number2021-12875
SectionProposed rules
CourtEnvironmental Protection Agency
Federal Register, Volume 86 Issue 117 (Tuesday, June 22, 2021)
[Federal Register Volume 86, Number 117 (Tuesday, June 22, 2021)]
                [Proposed Rules]
                [Pages 32656-32669]
                From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
                [FR Doc No: 2021-12875]
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                ENVIRONMENTAL PROTECTION AGENCY
                40 CFR Part 52
                [EPA-R08-OAR-2021-0262; FRL-10025-02-Region 8]
                Approval and Promulgation of Implementation Plans; Colorado;
                Revisions to Regulation Number 7; Aerospace, Oil and Gas, and Other
                RACT Requirements for 2008 8-Hour Ozone Standard for the Denver Metro/
                North Front Range Nonattainment Area
                AGENCY: Environmental Protection Agency (EPA).
                ACTION: Proposed rule.
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                SUMMARY: The Environmental Protection Agency (EPA) is proposing
                approval of State Implementation Plan (SIP) revisions submitted by the
                State of Colorado on May 14, 2018, May 8, 2019, and May 13, 2020. The
                revisions are to Colorado Air Quality Control Commission (Commission or
                AQCC) Regulation Number 7 (Reg. 7). The revisions to Reg. 7 address
                Colorado's SIP obligation to require reasonably available control
                technology (RACT) for sources covered by the 2016 oil & natural gas
                control techniques guidelines (CTG or CTGs) for Moderate nonattainment
                areas under the 2008 ozone National Ambient Air Quality Standard
                (NAAQS); update RACT requirements for major sources of volatile organic
                compounds (VOC) and nitrogen oxides (NOx); reorganize the
                regulation; add incorporation by reference dates to rules and reference
                [[Page 32657]]
                methods; and make typographical, grammatical, and formatting
                corrections. Also, the EPA is proposing to finalize approval of the
                State's negative declaration that there are no sources in the Denver
                Metro/North Front Range (DMNFR) Area subject to the aerospace CTG,
                which was conditionally approved in our February 24, 2021 rulemaking.
                The EPA is taking this action pursuant to the Clean Air Act (CAA).
                DATES: Written comments must be received on or before July 22, 2021.
                ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
                OAR-2021-0262, to the Federal Rulemaking Portal: https://www.regulations.gov. Follow the online instructions for submitting
                comments. Once submitted, comments cannot be edited or removed from
                www.regulations.gov. The EPA may publish any comment received to its
                public docket. Do not submit electronically any information you
                consider to be Confidential Business Information (CBI) or other
                information whose disclosure is restricted by statute. Multimedia
                submissions (audio, video, etc.) must be accompanied by a written
                comment. The written comment is considered the official comment and
                should include discussion of all points you wish to make. The EPA will
                generally not consider comments or comment contents located outside of
                the primary submission (i.e., on the web, cloud, or other file sharing
                system). For additional submission methods, the full EPA public comment
                policy, information about CBI or multimedia submissions, and general
                guidance on making effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.
                 Docket: All documents in the docket are listed in the
                www.regulations.gov index. Although listed in the index, some
                information is not publicly available, e.g., CBI or other information
                whose disclosure is restricted by statute. Certain other material, such
                as copyrighted material, will be publicly available only in hard copy.
                Publicly available docket materials are available electronically in
                www.regulations.gov. To reduce the risk of COVID-19 transmission, for
                this action we do not plan to offer hard copy review of the docket.
                Please email or call the person listed in the FOR FURTHER INFORMATION
                CONTACT section if you need to make alternative arrangements for access
                to the docket.
                FOR FURTHER INFORMATION CONTACT: Abby Fulton, Air and Radiation
                Division, EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver,
                Colorado 80202-1129, (303) 312-6563, [email protected].
                SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
                ``us,'' or ``our'' is used, we mean the EPA.
                I. What action is the EPA taking?
                 As explained below, the EPA is proposing to approve various
                revisions to the Colorado SIP that were submitted to the EPA on May 14,
                2018, May 8, 2019, May 13, 2020, and March 22, 2021. In particular, we
                propose to approve certain Reg. 7 rules to meet the 2008 8-hour ozone
                NAAQS oil and gas CTG RACT requirements for Moderate nonattainment
                areas that were not acted on in our July 3, 2018 \1\ and February 24,
                2021 \2\ rulemakings. We are also proposing to approve certain area
                source rules as meeting the 2008 8-hour ozone NAAQS RACT requirements
                for Serious nonattainment areas. Additionally, we are proposing to
                finalize approval of the State's negative declaration that there are no
                sources in the DMNFR Area subject to the aerospace CTG, which was
                conditionally approved in our February 24, 2021 \3\ rulemaking.
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                 \1\ Final Rule, Approval and Promulgation of State
                Implementation Plan Revisions; Colorado; Attainment Demonstration
                for the 2008 8-Hour Ozone Standard for the Denver Metro/North Front
                Range Nonattainment Area, and Approval of Related Revisions, 83 FR
                31068, 31069-31072.
                 \2\ Final Rule, Approval and Promulgation of Implementation
                Plans; Colorado; Revisions to Regulation Number 7 and RACT
                Requirements for 2008 8-Hour Ozone Standard for the Denver Metro/
                North Front Range Nonattainment Area, 86 FR 11125, 11126 -11127.
                 \3\ 86 FR 11125.
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                 The specific bases for our proposed actions, our analyses, and
                proposed findings are discussed in this proposed rulemaking. Technical
                information that we are relying on is in the docket, available at
                http://www.regulations.gov, Docket No. EPA-R08-OAR-2021-0262.
                II. Background
                2008 8-Hour Ozone NAAQS Nonattainment
                 On March 12, 2008, the EPA revised both the primary and secondary
                NAAQS for ozone to a level of 0.075 parts per million (ppm) (based on
                the annual fourth-highest daily maximum 8-hour average concentration,
                averaged over 3 years), to provide increased protection of public
                health and the environment.\4\ The 2008 ozone NAAQS retains the same
                general form and averaging time as the 0.08 ppm NAAQS set in 1997, but
                is set at a more protective level. Specifically, the 2008 8-hour ozone
                NAAQS is attained when the 3-year average of the annual fourth-highest
                daily maximum 8-hour average ambient air quality ozone concentrations
                is less than or equal to 0.075 ppm.\5\
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                 \4\ Final rule, National Ambient Air Quality Standards for
                Ozone, 73 FR 16436 (March 27, 2008). The EPA has since further
                strengthened the ozone NAAQS, but the 2008 8-hour standard remains
                in effect. See Final Rule, National Ambient Air Quality Standards
                for Ozone, 80 FR 65292 (Oct. 26, 2015).
                 \5\ 40 CFR 50.15(b).
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                 Effective July 20, 2012, the EPA designated as nonattainment any
                area that was violating the 2008 8-hour ozone NAAQS based on the three
                most recent years (2008-2010) of air monitoring data.\6\ With that
                rulemaking, the Denver-Boulder-Greeley-Ft. Collins-Loveland, Colorado
                area (Denver or DMNFR Area) area was designated nonattainment and
                classified as Marginal.\7\ Ozone nonattainment areas are classified
                based on the severity of their ozone levels, as determined using the
                area's design value. The design value is the 3-year average of the
                annual fourth highest daily maximum 8-hour average ozone concentration
                at a monitoring site.\8\ Areas that were designated as Marginal
                nonattainment were required to attain the 2008 8-hour ozone NAAQS no
                later than July 20, 2015, based on 2012-2014 monitoring data.\9\
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                 \6\ Final rule, Air Quality Designations for the 2008 Ozone
                National Ambient Air Quality Standards, 77 FR 30088 (May 21, 2012).
                 \7\ Id. at 30110. The nonattainment area includes Adams,
                Arapahoe, Boulder, Broomfield, Denver, Douglas and Jefferson
                Counties, and portions of Larimer and Weld Counties. See 40 CFR
                81.306.
                 \8\ 40 CFR part 50, appendix I.
                 \9\ See 40 CFR 51.903.
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                 On May 4, 2016, the EPA published its determination that the Denver
                Area, among other areas, had failed to attain the 2008 8-hour ozone
                NAAQS by the attainment deadline, and that it was accordingly
                reclassified to Moderate ozone nonattainment status.\10\ Colorado
                submitted SIP revisions to the EPA on May 31, 2017 to meet the Denver
                Area's requirements under the Moderate classification.\11\ The EPA took
                final action on July 3, 2018, approving the majority of the May 31,
                2017 submittal, but deferring action on portions of the submitted Reg.
                7 RACT rules.\12\ On February 24, 2021, the EPA took final action
                approving additional RACT SIP
                [[Page 32658]]
                obligations for Moderate ozone nonattainment areas.\13\
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                 \10\ Final rule, Determinations of Attainment by the Attainment
                Date, Extensions of the Attainment Date, and Reclassification of
                Several Areas for the 2008 Ozone National Ambient Air Quality
                Standards, 81 FR 26697 (May 4, 2016).
                 \11\ CAA section 182, 42 U.S.C. 7511a, outlines SIP requirements
                applicable to ozone nonattainment areas in each classification
                category. Areas classified Moderate under the 2008 8-hour ozone
                NAAQS had a submission deadline of January 1, 2017 for these SIP
                revisions. 81 FR at 26699.
                 \12\ 83 FR at 31068.
                 \13\ 86 FR 11125.
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                 Areas that were designated as Moderate nonattainment were required
                to attain the 2008 8-hour ozone NAAQS no later than July 20, 2018,
                based on 2015-2017 monitoring data.\14\ On December 26, 2019, the EPA
                published its determination that the Denver Area, among other areas,
                had failed to attain the 2008 8-hour ozone NAAQS by the attainment
                deadline, and that it was accordingly reclassified to Serious ozone
                nonattainment status.\15\
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                 \14\ See 40 CFR 51.903.
                 \15\ Final rule, Finding of Failure To Attain and
                Reclassification of Denver Area for the 2008 Ozone National Ambient
                Air Quality Standard, 84 FR 70897 (Dec. 26, 2019); see 40 CFR
                81.306.
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                SIP Control Measures, Reg. 7
                 Colorado's Reg. 7, entitled ``Control of Ozone via Ozone Precursors
                and Control of Hydrocarbons via Oil and Gas Emissions,'' contains
                general RACT requirements as well as specific emission limits
                applicable to various industries. The EPA approved the repeal and re-
                promulgation of Reg. 7 in 1981,\16\ and has approved various revisions
                to parts of Reg. 7 over the years. In 2008, the EPA approved revisions
                to the control requirements for condensate storage tanks in Section
                XII,\17\ and later approved revisions to Reg. 7, Sections I through XI
                and Sections XIII through XVI.\18\ The EPA also approved Reg. 7
                revisions to Section XVII.E.3.a establishing control requirements for
                rich-burn reciprocating internal combustion engines.\19\ In 2018 the
                EPA approved Reg. 7 revisions in Sections XII (VOC emissions from oil
                and gas operations) and XIII (emission control requirements for VOC
                emissions from graphic art and printing processes), as well as non-
                substantive revisions to numerous other parts of the regulation.\20\
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                 \16\ Final rule, Colorado: Approval and Promulgation of State
                Implementation Plans, 46 FR 16687 (March 13, 1981).
                 \17\ Final rule, Approval and Promulgation of Air Quality
                Implementation Plans; State of Colorado; Regulation No. 7, Section
                XII, Volatile Organic Compounds From Oil and Gas Operations, 73 FR
                8194 (Feb. 13, 2008).
                 \18\ Final rule, Approval and Promulgation of State
                Implementation Plans; State of Colorado; Attainment Demonstration
                for the 1997 8-Hour Ozone Standard, and Approval of Related
                Revisions, 76 FR 47443 (Aug. 5, 2011).
                 \19\ Final rule, Approval and Promulgation of Implementation
                Plans; State of Colorado; Regional Haze State Implementation Plan,
                77 FR 76871 (Dec. 31, 2012).
                 \20\ See 83 FR at 31068, 31071.
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                 Most recently, in 2021 the EPA approved Reg. 7 revisions in
                Sections I (Applicability), IX (Surface Coating Operations), X (Use of
                Cleaning Solvents), XIII (Graphics Arts and Printing), XVI (Controls of
                Emissions from Stationary and Portable Engines and Other Combustion
                Equipment in the 8-Hour Ozone Control Area), and XIX (Control of
                Emissions from Specific Major Sources of VOC and/or NOX in
                the 8-hour Ozone Control Area). Revisions to incorporation by reference
                dates to rules and reference methods in Sections II, VI, VIII, IX, X,
                XII, XIII, XVI and XVII were also approved, as well as non-substantive
                revisions to numerous other parts of the regulation.\21\
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                 \21\ 86 FR 11125 (Feb. 24, 2021).
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                III. Summary of the State's SIP Submittals
                 We are proposing to take action on Colorado SIP submittals made on
                four three different dates:
                May 14, 2018 Submittal
                 This submittal contains amendments to Reg. 7 Sections XII (Volatile
                Organic Compound Emissions from Oil and Gas Operations) and XVIII
                (Natural Gas-Actuated Pneumatic Controllers Associated with Oil and Gas
                Operations) to meet RACT for oil and gas sources covered by the EPA's
                2016 Oil and Gas CTG.\22\
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                 \22\ Control Techniques Guidelines for the Oil and Natural Gas
                Industry, EPA-453/B-16-001 (Oct. 2016).
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                May 8, 2019 Submittal
                 This submittal contains typographical, grammatical, and formatting
                corrections to Reg. 7 Sections XII and XVIII that were not acted on in
                our February 24, 2021 action.\23\
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                 \23\ 86 FR 11125.
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                May 13, 2020 Submittal
                 This submittal includes a full reorganization of Reg. 7 into Parts
                A-E, and amends oil and gas storage tank requirements to establish a
                storage tank control threshold, updates storage tank monitoring
                requirements, and aligns related recordkeeping and reporting. The
                submittal also updates RACT requirements for major sources of VOC and
                NOX in the DMNFR area, including expanded categorical
                combustion equipment requirements in Part E, Section II (formally
                Section XVI.D.) and new categorical general solvent use requirements in
                Part C, Section II (formerly Section X.). The submittal also includes
                updates to the requirements for gasoline transport truck testing and
                vapor control systems, and contains typographical, grammatical, and
                formatting corrections throughout.
                IV. Procedural Requirements
                 The CAA requires that states meet certain procedural requirements
                before submitting SIP revisions to the EPA, including the requirement
                that states adopt SIP revisions after reasonable notice and public
                hearing.\24\
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                 \24\ CAA section 110(a)(2), 42 U.S.C. 7410(a)(2),
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                 For the May 14, 2018 submittal, the AQCC provided notice in the
                Colorado Register on July 22, 2017 and held public hearings on the
                revisions on October 19 and 20, 2017. The Commission adopted the SIP
                revisions on November 17, 2017. The SIP revisions became state-
                effective on December 30, 2017.
                 For the May 8, 2019 submittal, the AQCC provided notice in the
                Colorado Register on August 18, 2018 and held a public hearing on the
                revisions on November 15, 2018. The Commission adopted the SIP
                revisions on November 15, 2018. The revisions became state-effective on
                January 14, 2019.
                 For the May 13, 2020 submittal, the AQCC provided notice in the
                Colorado Register on September 25, 2019 and held public hearings on the
                revisions on December 17-19, 2019. The Commission adopted the SIP
                revisions on December 19, 2019. The SIP revisions became state-
                effective on February 14, 2020.
                 Accordingly, we propose to find that Colorado met the CAA's
                procedural requirements for reasonable notice and public hearing.
                V. Reasonably Available Control Technology (RACT) Analysis
                A. Background
                 The CAA requires that SIPs for nonattainment areas implement RACT
                for each category of VOC sources in the area covered by a CTG and all
                other major stationary sources of VOC.\25\ The EPA has defined RACT as
                the lowest emissions limitation that a particular source is capable of
                meeting by the application of control technology that is reasonably
                available, considering technological and economic feasibility.\26\ The
                CAA amendments of 1990 introduced the requirement for existing major
                stationary sources of NOX in nonattainment areas to install
                and operate NOX RACT.\27\
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                 \25\ CAA section 182(b)(2).
                 \26\ Proposed rule, General Preamble for Proposed Rulemaking on
                Approval of Plan Revisions for Nonattainment Areas--Supplement (on
                Control Techniques Guidelines), 44 FR 53761, 53762 (Sep. 17, 1979).
                 \27\ CAA Section 182(f).
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                 The EPA provides guidance concerning what types of controls can
                constitute RACT for a given source
                [[Page 32659]]
                category by issuing CTG and Alternative Control Techniques (ACT)
                documents.\28\ States must submit a SIP revision requiring the
                implementation of RACT for each source category in the area for which
                the EPA has issued a CTG, and for any major source in the area not
                covered by a CTG.\29\
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                 \28\ See https://www.epa.gov/ground-level-ozone-pollution/control-techniques-guidelines-and-alternative-control-techniques
                (accessed May 20, 2021) for a list of the EPA-issued CTGs and ACTs
                (also available within the docket).
                 \29\ See CAA section 182(b)(2), 42 U.S.C. 7511a(b)(2)). See also
                Note, RACT Qs & As--Reasonably Available Control Technology (RACT):
                Questions and Answers, William Harnett, Director, Air Quality Policy
                Division, EPA (May 2006), available at https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20060518_harnett_ract_q&a.pdf.
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                 For a Serious nonattainment area, a major stationary source is one
                that emits, or has the potential to emit, 50 tons per year (tpy) or
                more of VOC or NOX.\30\ RACT can be adopted in the form of
                emission limitations or ``work practice standards or other operation
                and maintenance requirements,'' as appropriate.\31\ In assessing RACT
                requirements under the Serious classification, the Colorado Air
                Pollution Control Division (Division) evaluated 31 major sources in
                their Technical Support Document (TSD),\32\ in addition to the major
                sources evaluated under the Moderate classification.
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                 \30\ See CAA sections 182(c), 42 U.S.C. 7511a(c).
                 \31\ See Memorandum, ``Approval Options for Generic RACT Rules
                Submitted to Meet the non-CTG VOC RACT Requirement and Certain
                NOX RACT Requirements,'' Sally Shaver, Director, Air
                Quality Strategies & Standards Division, EPA (Nov. 7, 1996),
                available at https://www.epa.gov/sites/production/files/2016-08/documents/shavermemogenericract_7nov1996.pdf.
                 \32\ Technical Support Document for Reasonably Available Control
                Technology for Major Sources, Dec. 11, 2019. P. 2134 of the May 13,
                2020 submittal.
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                 On October 20, 2016, the EPA issued final CTGs for reducing VOC
                emissions from existing oil and natural gas equipment and
                processes.\33\ Under the schedule in the oil and gas CTG, revisions to
                SIP RACT provisions for sources covered by the CTG were due on October
                27, 2018. Sources covered by the CTG include those located in 2008
                ozone NAAQS nonattainment areas classified as Moderate (or higher). The
                emissions controls determined by the State to be RACT for sources
                covered by the oil and gas CTG were required to be implemented as soon
                as practicable, but no later than January 1, 2021.\34\ In November
                2017, the Commission adopted revisions to Reg. 7 that addressed RACT
                requirements for each category of sources covered by the oil and gas
                CTG.
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                 \33\ Notice of availability, Release of Final Control Techniques
                Guidelines for the Oil and Natural Gas
                 Industry, 81 FR 74798 (Oct. 27, 2016). See also Control
                Techniques Guidelines for the Oil and Natural Gas Industry, EPA-453/
                B-16-001 (Oct. 2016).
                 \34\ Docket ID No. EPA-HQ-OAR-2015-0216-0238.
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                 In December 2019, the Commission adopted new SIP requirements to
                include provisions that implement RACT for some major sources of VOC
                and NOX by incorporating by reference new source performance
                standards (NSPS) and/or national emission standards for hazardous
                pollutants (NESHAP) requirements for specific points at major sources;
                requiring specific sources to provide RACT analyses to the Division for
                specified facilities and/or emission points to inform future
                categorical RACT rulemakings; expanding categorical combustion
                equipment requirements in Part E, Section II. (formerly Section XVI.D.)
                to facilities with NOx emissions greater than or equal to 50 tpy; and
                establishing categorical RACT requirements for general solvent use.
                B. Evaluation
                 As part of its May 14, 2018 and May 13, 2020 submittals, the
                Division conducted RACT analyses to demonstrate that the RACT
                requirements for the oil and gas CTG and certain major sources in the
                DMNFR 2008 8-hour ozone NAA have been fulfilled. The Division conducted
                these RACT analyses for VOC and NOX by listing the state
                regulation that implements or exceeds RACT requirements for the CTG
                category or non-CTG category at issue, and by detailing the basis for
                concluding that these regulations fulfill RACT, through comparison with
                established RACT requirements described in the CTG and ACT guidance
                documents. A summary of our proposed action with respect to each RACT
                category follows.
                 Table 1--Source Categories, Proposed Action, and Corresponding Sections of Submittals
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                 Category Proposed action Location of RACT demonstration
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                Aerospace............................. Approval...................... Negative declaration. p. 6-3 of
                 Colorado's Serious State Implementation
                 Plan for the Denver Metro and North
                 Front Range Ozone Nonattainment Area.35
                General solvent use at major sources.. Approval...................... pp. 619-620, 706, 2800, 2803 and
                 Technical Support Document for
                 Reasonably Available Control Technology
                 for Major Sources (document number 56,
                 p. 2134) of the May 13, 2020
                 submission.
                Oil and gas........................... Approval...................... Technical Support Document for
                 Reasonably Available Control Technology
                 for the Oil and Gas Industry (document
                 set 38) of the May 14, 2018 submittal.
                 pp. 417-425 of the May 13, 2020
                 submittal.
                Emissions from stationary internal Approval...................... pp. 619, 622, 724, 2800-2801, 2803 and
                 combustion engines and flares at Technical Support Document for
                 certain major sources. Reasonably Available Control Technology
                 for Major Sources (document number 56,
                 p. 2134) of the May 13, 2020
                 submission.
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                Cited materials are in the docket for this action.
                 In our July 3, 2018 and February 24, 2021 rulemakings, we approved
                Colorado's demonstration of RACT for certain VOC CTG sources \36\ for
                the 2008 8-hour ozone standard. Today we are taking action on the RACT
                demonstrations for Oil and Gas CTG categories and certain additional
                non-CTG VOC and NOx sources and categories. We have reviewed Colorado's
                new and revised VOC rules for the source categories covered by the Oil
                and Gas CTG, and for major sources of non-CTG VOC and NOx sources for
                the 2008 8-hour ozone NAAQS, and the demonstrations submitted by
                Colorado. Based on this review we propose to find that these rules are
                consistent with the
                [[Page 32660]]
                control measures, definitions, recordkeeping, and test methods in the
                CTG and the CAA, and that they satisfy CAA RACT requirements for the
                categories in question.\37\
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                 \35\ See Colorado's March 22, 2021 submittal, document set 16
                (in the docket for this action).
                 \36\ 83 FR at 31069-31070; see Proposed Rule, Promulgation of
                State Implementation Plan Revisions; Colorado; Attainment
                Demonstration for the 2008 8-Hour Ozone Standard for the Denver
                Metro/North Front Range Nonattainment Area, and Approval of Related
                Revisions, 83 FR 14807, 14814-141815, Tables 5 and 6 (Apr. 6, 2018).
                 \37\ See https://www.epa.gov/ground-level-ozone-pollution/ract-information.
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                1. RACT for CTG Sources
                 Table 2 contains the CTG source category, the EPA reference
                document, and the corresponding sections of Reg. 7 that fulfill the
                applicable RACT requirements for the EPA-issued CTGs.\38\ Colorado's
                Reg. 7 contains SIP-approved \39\ and submitted revisions (see Section
                VI of this document); we propose to find that these revisions meet RACT
                requirements for the source category listed in Table 2.
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                 \38\ See the EPA's TSD for a full analysis of Colorado's rules
                as they relate to the EPA's guidelines and available technical
                information.
                 \39\ See 76 FR at 47443 and 83 FR at 31069-31070.
                 \40\ P. 2134 of the May 13, 2020 submittal.
                 \41\ See the EPA's TSD for a full analysis of Colorado's rules
                as they relate to the EPA's guidelines and available technical
                information.
                 \42\ Colorado's major source RACT analysis can be found on pp.
                1119-1120 and 1142-1149 of the May 31, 2017 submittal and the
                Technical Support Document for Reasonably Available Control
                Technology for Major Sources, November 17, 2016 (pp. 2990-3273 of
                May 31, 2017 submittal).
                Table 2--Source Category, the EPA's CTG Reference Document, and Corresponding Sections of Reg. 7 Fulfilling RACT
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                 Reg. 7 sections fulfilling
                 Source category in DMNFR area CTG reference document Date of CTG RACT
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                Oil and Gas..................... Control Techniques Guidelines 2016 Sections XII, XVIII, and
                 for the Oil and Natural Gas revised Section D (proposed
                 Industry. for approval in this
                 action).
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                 We have reviewed the emission limitations and control requirements
                for the above source category and compared them against the EPA's CTG
                document and available technical information in CTG dockets. The EPA
                has also evaluated the submitted rules and has determined that they are
                consistent with the CAA, the EPA's regulations, and the EPA's policies.
                For more information, see the EPA TSD prepared in conjunction with this
                action. Based on the information in the record, we propose to find that
                the corresponding sections in Reg. 7 provide for the lowest emission
                limitation through application of control techniques that are
                reasonably available considering technological and economic
                feasibility. Therefore, we propose to find that the control
                requirements for the oil and gas source category are RACT for all
                affected sources in the DMNFR Area under the 2008 8-hour ozone NAAQS.
                2. RACT for Non-CTG Major Sources
                 In Colorado's Technical Support Document for Reasonably Available
                Control Technology for Major Sources,\40\ Colorado identified a list of
                major non-CTG VOC and NOX sources in the DMNFR Area subject
                to RACT requirements under a Serious classification. For major VOC and
                NOX sources subject to nonattainment area RACT review,
                Colorado used the construction permit thresholds established in the
                State's Reg. 3 for determining which emission points to review.
                Accordingly, emission points exceeding two tpy of VOC at a major VOC
                source and five tpy of NOX at a major NOX source,
                as reported on a source's Air Pollutant Emission Notice, and that were
                not part of the Moderate RACT review, were evaluated. We have reviewed
                the State's May 13, 2020 submittal and find its approach to including
                these sources in the inventory acceptable. To satisfy the Serious RACT
                SIP requirement to establish RACT for all existing major sources of VOC
                and/or NOX in the DMNFR Area, the Commission incorporated by
                reference several NSPS and NESHAP regulations. The Division also
                expanded the stationary combustion equipment standards and developed
                new general solvent use requirements, based on a detailed review of
                available information on major NOX and VOC sources in the
                DMNFR Area, an examination of the EPA RACT/Best Available Control
                Technology/Lowest Achievable Emission Rate Clearinghouse for similar
                emission points, and consideration of CAA section 182(b) RACT
                requirements for other ozone nonattainment areas. Table 3 contains a
                list of non-CTG source categories, the EPA's reference documents, and
                the corresponding sections of Reg. 7 that are proposed for approval in
                this action to fulfill RACT requirements (see Section VI of this
                document).\41\
                 Table 3--Source Categories, the EPA's Reference Documents, and
                 Corresponding Sections of Reg. 7 Proposed for Approval To Fulfill RACT
                ------------------------------------------------------------------------
                 The EPA's reference
                Source category in the DMNFR document or Reg. 7 sections
                 area 42 regulation (if fulfilling RACT
                 applicable)
                ------------------------------------------------------------------------
                General solvent use at major .................... Part C, Section II.F
                 sources. (proposed for
                 approval in this
                 action).
                Stationary internal NOX Emissions from Applicable
                 combustion engines. Stationary Internal provisions in Part
                 Combustion Engines E, Section II.
                 (EPA-453/R-93-032).
                Flares...................... 40 CFR 60, Subpart Part E, Section
                 A, Section 60.18 III.B.2.
                 General Provisions,
                 General control
                 device and work
                 practice
                 requirements.
                ------------------------------------------------------------------------
                 We have reviewed the emission limitations and control requirements
                for the source categories in Table 3 and compared them to the EPA's
                regulations, ACT documents, available technical information, and
                guidelines. The EPA has also evaluated the submitted rules \43\ and has
                determined that they are consistent with the CAA, the EPA's
                regulations, and the EPA's policies. For more information, see the EPA
                TSD prepared in conjunction with this action. Based on the information
                in the record, we propose to find that the corresponding sections in
                Reg. 7
                [[Page 32661]]
                provide for the lowest emission limitation through application of
                control techniques that are reasonably available considering
                technological and economic feasibility. Therefore, we propose to find
                that the control requirements for the source categories identified in
                Table 3 are RACT for all affected sources in the DMNFR Area under the
                2008 8-hour ozone NAAQS.
                VI. The EPA's Evaluation of SIP Control Measures in Reg. 7
                 We evaluated Colorado's May 14, 2018, May 8, 2019, and May 13, 2020
                submittals regarding revisions to the State's Reg. 7 to meet RACT
                requirements for various source categories. Revisions to Reg. 7 include
                expansion of categorical combustion equipment requirements;
                incorporation by reference of certain NSPS and NESHAP requirements for
                engines and landfill gas flares; RACT analysis requirements for
                specified facilities and/or emission points; emission control
                requirements for general solvent use; and updated requirements for
                gasoline transport truck testing and vapor control systems. The
                revisions establish RACT requirements for the oil and gas CTG category
                and emission points at major sources of VOC and NOX in the
                DMNFR Area. Reg. 7 revisions also add incorporation by reference dates
                to rules and reference methods; reorganize and renumber the regulation;
                and correct typographical, grammatical, and formatting errors. For ease
                of review, Colorado submitted the full text of Reg. 7 as SIP revisions
                (with the exception of provisions designated ``State Only''). The EPA
                is only seeking comment on Colorado's proposed substantive changes to
                the SIP-approved version of Reg. 7, which are described below. We are
                not seeking comment on incorporation into the SIP of the revised
                portions of the regulation that were previously approved into the SIP
                and have not been substantively modified by the State as part of any of
                these submittals.
                 As noted above, Colorado designated various parts of Reg. 7 State
                Only, and in Section I.A.1.c indicated that sections designated State
                Only are not federally enforceable. The EPA concludes that provisions
                designated State Only have not been submitted for the EPA's approval,
                but for informational purposes. Hence, the EPA is not proposing to act
                on the portions of Reg. 7 designated State Only, and this proposed rule
                does not discuss them further except as relevant to discussion of the
                portions of the regulation that Colorado intended to be federally
                enforceable.
                A. Evaluation
                1. May 14, 2018 SIP Submittal
                 The State's May 14, 2018 SIP submittal contains amendments to Reg.
                7, Sections II.B., XII and XVIII to meet RACT for oil and gas sources
                covered by the EPA's 2016 Oil and Gas CTG. The submittal also includes
                clarifying revisions and typographical, grammatical, and formatting
                corrections throughout Reg. 7. We propose to approve the revisions to
                Sections XII and XVIII included in Colorado's May 14, 2018 submittal as
                identified in Table 5. All remaining Sections of the May 14, 2018
                submittal were approved with our February 24, 2021 action.\44\ Below,
                we describe in detail Colorado's proposed revisions and the basis for
                our proposed approval of them. Additional analysis on how revisions
                meet RACT requirements can be found in the TSD for this action.
                ---------------------------------------------------------------------------
                 \44\ 86 FR 11125 (Feb. 24, 2021).
                ---------------------------------------------------------------------------
                a. Section II
                 Section II includes general provisions for Reg. 7. The revisions to
                Section II.B. clarify that the Section XII.L. hydrocarbon threshold and
                Section XVIII natural gas emission standards serve as VOC indicators
                and that the SIP does not regulate hydrocarbon emissions.
                 We propose to find that the revisions clarify Sections XII.L.,
                XVIII.C.1. and XVIII.C.2. and are consistent with CAA requirements and
                CTGs. We therefore propose to approve the changes in Section II.B.
                b. Section XII
                 Section XII regulates VOC emissions from, and establishes RACT for,
                oil and gas operations. Section XII applies to operations that involve
                the collection, storage, or handling of condensate in the DMNFR Area.
                Changes to Sections XII.A. through XII.D. and XII.F. through XII.F.L.
                include addition of definitions for terms used in oil and gas
                operations; clarifications to Colorado's ozone season; updates to the
                leak detection and repair program; new provisions for centrifugal and
                reciprocating compressors, natural gas driven diaphragm pumps, and
                fugitive emissions at well production facilities and natural gas
                compressor stations; and minor clerical \45\ revisions that do not
                affect the substance of the requirements.
                ---------------------------------------------------------------------------
                 \45\ When we describe changes as clerical in this proposed
                action, we are referring to changes like section renumbering;
                alphabetizing of definitions; minor grammatical, editorial, and
                typographical revisions; and changes in capitalization.
                ---------------------------------------------------------------------------
                (i) Section XII.B.
                 Section XII.B. contains definitions specific to oil and gas
                operations in Section XII. New definitions were added for ``approved
                instrument monitoring method,'' ``centrifugal compressor,''
                ``component,'' ``connector,'' ``custody transfer,'' ``infra-red
                camera,'' ``natural gas compressor station,'' ``natural gas-driven
                diaphragm pump,'' ``natural gas processing plant,'' ``reciprocating
                compressor,'' and ``well production facility.'' The definitions are
                clear, straightforward, and accurate.
                (ii) Section XII.C.1.
                 Section XII.C.1. includes provisions that are generally applicable
                to Section XII. Section XII.C.1.e.(iv) adds a new requirement for
                combustion devices installed on or after January 1, 2018 and used to
                comply with Sections XII.J. or XII.K. to be equipped with an
                operational auto-igniter upon installation. We propose to find that the
                revisions to Section XII.C.1. meet CAA and RACT requirements, and that
                they strengthen the SIP.
                (iii) Section XII.G.
                 Section XII.G. includes requirements for natural gas-processing
                plants in the 8-hour Ozone Control Area. Section XII.G.1. updates the
                leak detection and repair (LDAR) program applicable to equipment leaks
                at natural gas processing plants in the DMNFR Area by requiring owners
                or operators to comply with 40 CFR part 60 (NSPS), Subparts OOOO or
                OOOOa, instead of complying with NSPS Subpart KKK, which is an earlier
                NSPS and less stringent. Subpart KKK requires sources to implement a
                NSPS Subpart VV level LDAR program, while Subpart OOOO requires sources
                to implement a NSPS Subpart VVa level LDAR program. The oil and gas CTG
                recommends a Subpart VVa level LDAR program for equipment at natural
                gas processing plants. Section XII.G.3. updates compliance dates for
                owners and operators of existing natural gas processing plants subject
                to Section XII.G. requirements. We propose to find that the revisions
                to Section XII.G. meet CAA and RACT requirements, and that they
                strengthen the SIP.
                (iv) Section XII.H.
                 Section XII.H. sets forth emission reduction requirements for
                glycol natural gas dehydrators. Section XII.H.6. establishes reporting
                requirements for sources subject to Section XII.H. The Commission
                revised references to ``ozone season'' in Section and XII.H.6. to
                reflect that the requirements now apply year-round, including during
                the
                [[Page 32662]]
                months of May to September.46 47 We propose to find that the
                revisions to Section XII.H. strengthen the SIP and meet CAA
                requirements.
                ---------------------------------------------------------------------------
                 \46\ In October 2015, the EPA finalized a revision to the ozone
                NAAQS that revised the length of Colorado's ozone season to year-
                round (Final rule, National Ambient Air Quality Standards for Ozone,
                80 FR 65292 (Oct. 26, 2015)).
                 \47\ We are also approving a similar provision in Section
                XII.F.4. The provision applies to the system-wide control strategy
                for condensate storage tanks. In this action, we are proposing
                approval of the control strategy for individual storage tanks in new
                Part D, Section I.D. which replaces the system-wide strategy
                controls in Section XII.
                ---------------------------------------------------------------------------
                (v) Section XII.J.
                 Section XII.J. contains new provisions for centrifugal and
                reciprocating compressors. Section XII.J.1.a. requires that by January
                2, 2018, VOC emissions from wet seal fluid degassing systems on wet
                seal centrifugal compressors located between the wellhead and the point
                of custody transfer to the natural gas transmission and storage segment
                must be reduced by at least 95%. Section XII.J.1.b. requires wet seal
                fluid degassing systems to be equipped with continuous, impermeable
                covers that are connected through a closed vent system that routes
                emissions from the wet seal fluid degassing system to the process or
                control device. Section XII.J.1.c. requires annual visual inspections
                of the cover and closed vent systems for defects that could result in
                air emissions.
                 Under Section XII.J.1.d., owners or operators must conduct annual
                EPA Method 21 inspections of covers and closed vent systems to
                determine whether they operate with VOC emissions less than 500 ppm.
                Section XII.J.1.e. requires first attempts at repair to occur no later
                than five days after detecting defects or leaks, and repairs to be
                completed no later than 30 days after detection. Section XII.J.1.f.
                sets forth criteria for delaying inspection or repair due to unsafe
                conditions and accessibility issues. Owners or operators are required
                to maintain records of each cover or closed vent system that is unsafe
                or difficult to inspect and schedule for inspection when circumstances
                allow.
                 Section XII.J.1.h. includes recordkeeping requirements to
                demonstrate compliance with Section XII.J.1. Owners and operators must
                maintain records for a minimum of five years. As an alternative to the
                inspection, repair, and recordkeeping provisions, owners and operators
                may inspect, repair, and document cover and closed vent systems in
                accordance with the LDAR program in Section XII.L. Section XII.J.1.j.
                allows owners and operators to comply with emissions, inspections,
                repair, and recordkeeping provisions of an NSPS including Subparts OOOO
                and OOOOa in lieu of Sections XII.J.1.a. through i.
                 Section XII.J.2. contains provisions for reciprocating compressors.
                Section XII.J.2.a. requires that the rod packing on reciprocating
                compressors located between the wellhead and the point of custody
                transfer to the natural gas transmission and storage segment be
                replaced every 26,000 hours of operation or every 36 months. Under
                Section XII.J.2.a., owners or operators of existing reciprocating
                compressors at natural gas processing plants were required to begin
                monitoring the reciprocating compressor hours of operation on January
                1, 2018 and conduct the first rod packing replacement before January 1,
                2021, or route emissions to a process beginning May 1, 2018.
                 Section XII.J.2.b. allows owners or operators the option to reduce
                VOC emissions by routing reciprocating compressor emissions using a rod
                packing emissions collection system that operates under negative
                pressure and routes the rod packing emissions through a closed vent
                system to a process. Owners and operators must conduct annual visual
                inspections of the cover and closed vent systems for defects that could
                result in air emissions. Section XII.J.2.b.(ii) requires owners and
                operators to conduct annual EPA Method 21 inspections of the cover and
                closed vent system to determine whether they operate with VOC emissions
                less than 500 ppm. Section XII.2.e. allows owners and operators to
                comply with emissions, inspections, repair, and recordkeeping
                provisions of an NSPS in lieu of Sections XII.J.2.a. through d.
                 First attempts at repair must be made within five days of
                discovery, and repairs must be completed within 30 days unless one of
                the justifications for delay of repair in Section XII.J.2.b.(iv)
                applies. Owners or operators may delay subsequent repair attempts of
                equipment where, during a scheduled shutdown, the owner or operator
                unsuccessfully repaired the leak requiring repair if repair is
                completed within two years of discovery. Delayed inspection or repairs
                of the closed vent system may occur under certain safety,
                accessibility, and feasibility circumstances described in Sections
                XII.J.2.b.(iv)(A) through (D).
                 Section XII.J.2.c. includes recordkeeping requirements to
                demonstrate compliance with Section XII.J.2. Owners and operators must
                maintain records for a minimum of five years. As an alternative to the
                inspection, repair, and recordkeeping provisions, Section XII.J.2.d.
                allows owners and operators to inspect, repair, and document cover and
                closed vent systems in accordance with the LDAR program in Section
                XII.L. Section XII.J.2.e. allows owners and operators to comply with
                emissions, inspections, repair, and recordkeeping provisions of an
                NSPS, including Subparts OOOO and OOOOa.
                 We propose to find that the provisions in the new Section XII.J.
                strengthen the SIP and meet CAA and RACT requirements.
                (vi) Section XII.K
                 Section XII.K adds requirements for pneumatic pumps. Section
                XII.K.1 requires that natural gas-driven diaphragm pneumatic pumps at
                natural gas processing plants have a VOC compound emissions rate of
                zero. Section XII.K.2. establishes a May 1, 2018 effective date for
                owners or operators to reduce emissions from natural gas-driven
                diaphragm pneumatic pumps at well production facilities by 95% within
                30 days of startup of the control device or route emissions to a
                process at the well production facility. Pneumatic pump emissions must
                be routed to the existing control device even if is unable to achieve a
                95% emission reduction if it is technically infeasible to route
                emissions to a process. Section XII.K.2.b. requires a 95% reduction
                from pneumatic pumps within 30 days of startup upon installation of a
                control device or once routing emissions to a process becomes
                technically feasible. Pneumatic pump emissions are exempt from controls
                if an engineering assessment by a qualified professional engineer
                determines that routing a pneumatic pump to a control device or process
                is technically infeasible. Pneumatic pumps routing emissions to the
                process or control device must connect through a closed vent system.
                 Sections XII.K.2.e. through h. require annual visual and EPA Method
                21 inspections of the closed vent system. First attempts at repairs
                must be made within five days of discovery, and repairs must be
                completed within 30 days unless one of the justifications for delay of
                repair in Sections XII.K.2.h. applies. Delayed inspection or repairs of
                the closed vent system may occur under certain safety, accessibility,
                and feasibility circumstances described in Sections XII.K.2.h.(i)
                through (iv).
                 Section XII.K.3. includes recordkeeping requirements to demonstrate
                compliance with Section XII.K. Owners and operators must
                [[Page 32663]]
                maintain records for a minimum of five years. As an alternative to the
                inspection, repair, and recordkeeping provisions, XII.K.4. allows
                owners and operators to inspect, repair, and document cover and closed
                vent systems in accordance with the LDAR program in Section XII.L.
                Section XII.K.5. allows owners and operators to comply with emissions,
                inspections, repair, and recordkeeping provisions of an NSPS in lieu of
                Sections XII.K.1. and XII.K.4.
                 We propose to find that the provisions in the new Section XII.K.
                strengthen the SIP and meet CAA and RACT requirements.
                (vii) Section XII.L
                 Section XII.L. establishes a new leak detection and repair (LDAR)
                program for well production facilities and natural gas compressor
                stations in the DMNFR Area.
                 This program, which we are now reviewing for approval into the SIP,
                took effect under state law beginning June 30, 2018. Under the LDAR
                program, owners or operators of natural gas compressor stations must
                inspect components for leaks using an approved instrument monitoring
                method (AIMM) at least quarterly.\48\ As defined in new section
                XII.B.3, AIMM means an infra-red camera, EPA Method 21, or another
                ``instrument based monitoring method or program'' that is approved in
                accordance with Section XII.L.8, discussed below. Initial inspections
                for leaks from components at natural gas compressor stations
                constructed on or after June 30, 2018 must be conducted no later than
                90 days after the facility commences operation and at least quarterly
                thereafter.
                ---------------------------------------------------------------------------
                 \48\ The SIP at Reg. 7, Section XII.E.3, already required an
                ``audio, visual, olfactory'' (AVO) inspection required for storage
                tanks subject to control requirements. That requirement remains in
                effect.
                ---------------------------------------------------------------------------
                 Owners or operators at well production facilities with uncontrolled
                actual VOC emissions greater than or equal to one ton per year and less
                than or equal to six tons per year must inspect components for leaks
                using an AIMM at least annually. Well production facilities with
                uncontrolled VOC emissions greater than six tons per year must be
                inspected at least semi-annually. Sections XII.L.2.c. and Section
                XII.L.2.d. set forth the criteria for determining inspection frequency
                and the timing of initial inspections. Initial inspections for well
                production facilities constructed on or after June 30, 2018 must be
                conducted no sooner than 15 days and no later than 30 days after the
                facility commences operation. Monitoring components is not required
                under certain safety, accessibility, and feasibility circumstances
                described in Sections XII.L3.a. through c.
                 Section XII.L.4. establishes thresholds for leaks requiring repair
                under Section XII.L.5. The first attempt to repair an identified leak
                must be made within five working days of discovery and completed within
                30 days unless one of the justifications for delay of repair in
                Sections XII.L.5.a(i) through (iii) applies. Leaks must be re-monitored
                within 15 working days of the repair.
                 Section XII.L.6. requires owners or operators to keep records to
                demonstrate compliance with the LDAR program and to maintain those
                records for a minimum of five years. Records include documentation of
                the initial approved AIMM inspection; facility identification
                information; leaks requiring repair and monitoring method used to
                determine presence of the leak; dates of first attempt to repair; dates
                and types of repairs; delayed repair lists; re-monitoring dates and
                results; and lists of components designated as unsafe, difficult, or
                inaccessible to monitor.
                 Section XII.L.7. requires that each facility's owner or operator
                submit an annual LDAR report to ensure that the data submitted to the
                Division accurately represents and summarizes the activities and
                effectiveness of the LDAR program. Reports should include the number of
                inspections, leaks requiring repair, leaking component type, and
                monitoring method by which the leaks were found.
                 Section XII.L.8. describes the process for review and approval of
                alternative AIMM for use as a part of the LDAR program. The provisions
                allow the use of an alternative AIMM in lieu of or in combination with
                the EPA-approved AIMM (i.e., infra-red cameras or Method 21), if
                certain conditions are met under Section XII.L.8.a. and if the Division
                approves the proposal.
                 Because the alternative AIMM regulation allows the authorization,
                outside of the SIP approval process, of a leak detection method not
                specified in the submitted regulatory language or elsewhere in the SIP,
                we must consider whether it impermissibly allows the state agency to
                revise the SIP at its own discretion. Concerns with such rules, often
                known as ``director's discretion'' provisions, are discussed in detail
                in EPA's 2015 final rule responding to a petition for rulemaking
                concerning how SIPs treat excess emissions during periods of startup,
                shutdown, or malfunction (SSM), often referred to as the ``SSM SIP
                Call'' rulemaking.\49\ As explained in the SSM SIP Call, the EPA
                interprets the CAA as prohibiting ``SIP provisions that include
                unlimited director's discretion to alter the SIP emission limitations
                applicable to source.'' \50\ But the SSM SIP Call also explains that
                there are circumstances in which a director's discretion provision may
                be consistent with the CAA and fully approvable, including ``when the
                director's discretion authority is adequately bounded such that the EPA
                can ascertain in advance, at the time of approving the SIP provision,
                how the exercise of that discretion to alter the SIP emission
                limitations for a source could affect compliance with other CAA
                requirements.'' \51\ The EPA has long held this position. As explained
                in a 1996 EPA guidance document, it may be appropriate for states to
                approve equally stringent source-specific alternatives to SIP-approved
                requirements, when the SIP includes language ``to provide substantive
                criteria governing the State's exercise of the alternative requirement
                authority.'' \52\
                ---------------------------------------------------------------------------
                 \49\ Final action, State Implementation Plans: Response to
                Petition for Rulemaking; Restatement and Update of EPA's SSM Policy
                Applicable to SIPs; Findings of Substantial Inadequacy; and SIP
                Calls to Amend Provisions Applying to Excess Emissions During
                Periods of Startup, Shutdown and Malfunction, 80 FR 33840, 33917-
                33924 (June 12, 2015).
                 \50\ Id. at 33917.
                 \51\ Id. at 33918.
                 \52\ White Paper Number 2 for Improved Implementation of the
                Part 70 Operating Permits Program (EPA OAQPS, March 5, 1996),
                Attachment B (``SIP Provisions For Establishing Alternative
                Requirements''), available at https://www.epa.gov/sites/production/files/2015-08/documents/wtppr-2.pdf.
                ---------------------------------------------------------------------------
                 Here, the EPA's view is that the State rule provides sufficient
                specific, substantive criteria to allow the EPA to evaluate the use of
                discretion in advance. Most significantly, under the provisions of
                Section XII.L.8, alternative AIMM must be ``capable of achieving
                emission reductions that are at least as effective as the emissions
                reductions achieved using an IR camera or Method 21.'' This requirement
                ensures that the State may not use its discretion to approve a method
                that is less effective than the SIP baseline.\53\ That is, in
                implementing the alternative AIMM program according to its
                requirements, which we are proposing to make a part of the SIP, the
                State will be unable to weaken any SIP provisions.
                ---------------------------------------------------------------------------
                 \53\ See Final Rule, Revisions to Air Plan; Arizona; Stationary
                Sources; New Source Review, 80 FR 67319, 67327 (Nov. 2, 2015)
                (approving rule as appropriately bounded because state agency ``does
                not have discretion to determine in which instances it will or won't
                apply the criteria'' in the regulation).
                ---------------------------------------------------------------------------
                [[Page 32664]]
                 It is important in reaching this conclusion that we are able to
                understand the State's process for determining whether an alternative
                AIMM is ``at least as effective'' as the two methods specified in the
                SIP. First, under the submitted rules at Section XII.L.8.a.(ii)(C), an
                alternative AIMM applicant must provide information on whether the
                proposed alternative is approved by other regulatory authorities, and
                for what application. This information will allow the State to assess
                the reliability and viability of the alternative. In addition, under
                Section XII.L.8.a.(ii)(D), the applicant must provide information, with
                supporting data, on the leak detection capabilities and limitations of
                the proposed alternative method. This data requirement is important to
                ensuring that the potential exercise of discretion in the alternative
                AIMM program is adequately bounded.
                 The State has further explained this process in a guidance document
                provided to the EPA.\54\ As explained in this document, in evaluating
                effectiveness, Colorado assumes that a certain level of emission
                reductions would be achieved using either infrared camera or Method 21
                AIMM, on a periodic basis with increasing emission reductions under
                greater monitoring frequencies, and compares the anticipated results of
                the proposed alternative AIMM to those numbers.\55\ Testing and
                modeling of the alternative AIMM is required.\56\ Thus, the State's
                program includes a quantitative evaluation according to specified
                criteria.
                ---------------------------------------------------------------------------
                 \54\ See Alternative AIMM Guidance & Procedures (CDPHE, Oct. 31,
                2019) (EPA-R08-OAR-2021-0262-0003).
                 \55\ See Alternative AIMM Guidance at 6.
                 \56\ In this respect the state's guidance, provided to EPA to
                assist in explaining the functioning of the state program, clarifies
                one arguable ambiguity in the submitted language. Specifically, the
                comma after ``data'' in XII.L.8.a.(ii)(I) leaves unclear whether the
                rule requires data or modeling, or data and modeling; the state's
                guidance makes clear that ``and'' is intended when it says that
                modeling should not be relied on exclusively for this demonstration,
                but that there should be testing as well. See also Letter from Garry
                Kaufman, Director, Air Pollution Control Division (March 24, 2021)
                providing clarifying information, available in the docket for this
                action.
                ---------------------------------------------------------------------------
                 Additional safeguards and constraints in the alternative AIMM
                process include:
                 The Alternative AIMM approval has to be made based on a
                record.
                 The State must provide public notice of the proposed
                alternative.
                 Approved alternative AIMM is made available to the public
                on a state website: https://cdphe.colorado.gov/alternative-aimm-public-notices.
                 One final feature of the State's alternative AIMM rule bears
                mentioning. It includes a requirement that the State agency submit the
                proposed alternative AIMM to the EPA for review. The alternative AIMM
                must receive the EPA's approval, but this approval may occur by default
                if the EPA does not disapprove the rule within six months. While this
                six-month EPA review period gives an additional opportunity for
                regulatory scrutiny of alternative AIMM proposals before approval, it
                is not equivalent to the SIP process, and is not the basis for our
                proposed approval of this action. Rather, it is because the alternative
                AIMM rules provide substantive criteria that constrain the State's
                exercise of discretion and allow the EPA to anticipate the impacts of
                the use of alternatives. For that reason, and as explained further
                above, we propose to approve the submitted new section XII.L.
                 A detailed evaluation of Section XII as a whole is in the TSD for
                this action. We propose to find that the submitted revisions to Section
                XII meet CAA and RACT requirements, and that they strengthen the SIP.
                c. Section XVIII
                 Section XVIII regulates emissions from natural gas-actuated
                pneumatic controllers located at or upstream of natural gas processing
                plants, and establishes RACT requirements for oil and gas operations.
                Section XVIII.C.1. requires that all pneumatic controllers installed on
                or before February 1, 2009 upstream of natural gas processing plants in
                the DMNFR Area must emit natural gas emissions in an amount equal to or
                less than a low-bleed pneumatic controller, unless a high-bleed
                pneumatic controller is required for safety or process purposes.
                Section XVIII.C.2. requires that all pneumatic controllers at natural
                gas processing plants have a bleed rate of zero unless a pneumatic
                controller with a bleed rate greater than zero is necessary due to
                safety and process. Monitoring and recordkeeping requirements are set
                forth in Sections XVIII.D. and XVIII.E. and include inspection,
                maintenance, and records demonstrating compliance with emission
                reduction requirements in Section XVIII.C. Section XVIII.D.2.
                establishes additional monitoring and maintenance for pneumatic
                controllers with a natural gas bleed rate greater than zero.
                 A detailed evaluation of Section XVIII is in the TSD for this
                action. We propose to find that the revisions to Section XVIII
                strengthen the SIP and meet CAA and RACT requirements. We therefore
                propose to approve the changes in Section XVIII.
                2. May 8, 2019 Submittal
                 The State's May 8, 2019 submittal contains typographical,
                grammatical, and formatting corrections to Reg. 7 Sections XII and
                XVIII that were not acted on in our February 24, 2021 action.\57\ The
                revisions do not change the substance of approved SIP provisions. We
                therefore propose to approve the revisions in Sections XII and XVIII.
                ---------------------------------------------------------------------------
                 \57\ 86 FR 11125.
                ---------------------------------------------------------------------------
                3. May 13, 2020 SIP Submittal
                 The State's May 13, 2020 SIP submittal contains amendments to Reg.
                7, including a full reorganization of the regulation into Parts A-E.
                Table 4 show the current Reg. 7 numbering as related to the proposed
                Reg. 7 renumbering.
                 Table 4--Current and Reorganized Reg. 7 Sections
                ------------------------------------------------------------------------
                 Reorganized Reg. 7
                 Current Reg. 7 sections sections
                ------------------------------------------------------------------------
                 Part A
                ------------------------------------------------------------------------
                I. Applicability............................. Part A, Section I.
                II. General Provisions....................... Part A, Section II.
                Appendix A. Colorado Ozone Nonattainment or Part A, Appendix A.
                 Attainment Maintenance Areas.
                ------------------------------------------------------------------------
                 Part B
                ------------------------------------------------------------------------
                III. General Requirements for Storage and Part B, Section I.
                 Transfer of Volatile Organic Compounds.
                IV. Storage of Highly Volatile Organic Part B, Section II.
                 Compounds.
                [[Page 32665]]
                
                V. Disposal of Volatile Organic Compounds.... Part B, Section III.
                VI. Storage and Transfer of Petroleum Liquids Part B, Section IV.
                VII. Crude Oil............................... Part B, Section V.
                VIII. Petroleum Processing and Refining...... Part B, Section VI.
                XV. Control of Volatile Organic Compound Part B, Section VII.
                 Leaks from Vapor Collection Systems and
                 Vapor Control Systems Located at Gasoline
                 Terminals, Gasoline Bulk Plants, and
                 Gasoline Dispensing Facilities.
                Appendix B. Criteria for Control of Vapors Part B, Appendix B.
                 from Gasoline Transfer to Storage Tanks.
                Appendix C. Criteria for Control of Vapors Part B, Appendix C.
                 from Gasoline Transfer at Bulk Plants (Vapor
                 Balance System).
                Appendix E. Test Procedures for Annual Removed (paragraphs B and
                 Pressure/Vacuum Testing of Gasoline E moved into section,
                 Transport Tanks. and references replaced
                 with EPA Method 27).
                ------------------------------------------------------------------------
                 Part C
                ------------------------------------------------------------------------
                IX. Surface Coating Operations............... Part C, Section I.
                X. Use of Cleaning Solvents.................. Part C, Section II.
                XI. Use of Cutback Asphalt................... Part C, Section III.
                XIII. Graphic Arts and Printing.............. Part C, Section IV.
                XIV. Pharmaceutical Synthesis................ Part C, Section V.
                Appendix D. Minimum Cooling Capacities for Part C, Appendix D.
                 Refrigerated Freeboard Chillers on Vapor
                 Degreasers.
                Appendix F. Emission Limit Conversion Part C, Appendix E.
                 Procedure.
                ------------------------------------------------------------------------
                 Part D
                ------------------------------------------------------------------------
                XII. Volatile Organic Compound Emissions from Part D, Section I.
                 Oil and Gas Operations.
                XVII. (State Only, except Section Part D, Section II.
                 XVII.E.3.a.,which was submitted as part of
                 the Regional Haze SIP) Statewide Controls
                 for Oil and Gas Operations and Natural Gas-
                 Fired Reciprocating Internal Combustion
                 Engines.
                ------------------------------------------------------------------------
                 Part E
                ------------------------------------------------------------------------
                XVI.A.-C. (natural gas fired reciprocating Part E, Section I.
                 internal combustion engines in the 8-hour
                 ozone control area) and XVII.E. (new,
                 modified, existing, and relocated natural
                 gas fired reciprocating internal combustion
                 engines).
                XVI.D. Control of Emissions from Stationary Part E, Section II.
                 and Portable Combustion Equipment in the 8-
                 Hour Ozone Control Area.
                XIX. Control of Emissions from Specific Major Part E, Section III.
                 Sources of VOC and/or NOX in the 8-Hour
                 Ozone Control Area.
                XX. Control of Emissions from Breweries in Part E, Section IV.
                 the 8-Hour Ozone Control Area.
                ------------------------------------------------------------------------
                 The State's May 13, 2020 SIP submittal also updates requirements
                for gasoline transport trucks, bulk terminals, and service stations;
                establishes a storage tank control threshold in lieu of the current
                system-wide control strategy; strengthens storage tank monitoring
                requirements; aligns related recordkeeping and reporting; and adds RACT
                requirements for major sources of VOC and/or NOx in the 8- hour Ozone
                Control Area. The submittal also includes clarifying revisions and
                typographical, grammatical and formatting corrections throughout Reg.
                7. We propose to approve the revisions to Reg. 7 included in Colorado's
                May 13, 2020 submittal as identified in Table 5. Below, we describe in
                detail Colorado's proposed revisions and the basis for our proposed
                approval of them. Additional analysis on how revisions meet RACT
                requirements can be found in the TSD for this action.
                a. Part A
                 The revisions add a new Part A heading, encompassing Sections I and
                II. Part A contains applicability and general provisions for Reg. 7.
                The revisions also include renumbering and updates to Parts and
                Sections referenced throughout Part A. The revisions do not change the
                substance of SIP approved rules. We therefore propose approval of the
                changes to Part A.
                b. Part B
                 The revisions add a new Part B heading for Sections I, II, III, IV,
                V, VI, VII (previously Reg. 7, Sections III through XV). and appendixes
                B and C. Part B regulates the storage, transfer, and disposal of VOC
                and petroleum liquids and petroleum processing and refining. The
                revisions to Reg. 7, Part B, Sections IV and VII update the gasoline
                transport truck testing and associated recordkeeping requirements and
                update and clarify the vapor system requirements. Revisions also
                include renumbering and updates to Parts and Sections referenced
                throughout Part B.
                 Section IV (previously Section VI) regulates the storage and
                transfer of petroleum liquid, and Section VII (previously Section XV)
                regulates VOC leaks from vapor collection systems located at gasoline
                terminals, gasoline bulk plans, and gasoline dispensing facilities.
                Revisions to Sections IV and VII and the removal of the former Appendix
                E update requirements for gasoline transport trucks, bulk terminals,
                and service stations to align with current federal requirements for
                gasoline transport truck testing and vapor control systems. Section
                IV.A.2.j. adds a new definition for ``vapor collection system.'' The
                definition is clear, straightforward, accurate, and
                [[Page 32666]]
                consistent with the definition in Sections IV.D.1.b.(ii) and VII.A.3.c.
                Revisions made in Section IV.B.3. clarify that vapor collection systems
                must be leak-tight and properly maintained and operated.
                 Section IV.D. regulates VOC leaks from gasoline transport trucks.
                Revision to Sections IV.D.2 and IV.D.3. replace the outdated vacuum-
                pressure test in the CTG for Control of Volatile Organic Compound Leaks
                from Gasoline Tank Trucks and Vapor Collection Systems \58\ with the
                more current EPA Method 27.\59\ Federal standards in NSPS XX \60\,
                NESHAP R \61\, NESHAP BBBBBB \62\, and NESHAP CCCCCC \63\ reference the
                EPA's Method 27, Determination of Vapor Tightness of Gasoline Delivery
                Tank Using Pressure Vacuum Test, in contrast to the CTG's pressure-
                vacuum test. The test values in Reg. 7 Section IV.D.4 were also updated
                and are based on the EPA's CTG and correspond to the EPA Method 27 test
                values in NSPS XX, NESHAP R, NESHAP BBBBBB, and NESHAP CCCCCC.
                Recordkeeping and certification requirements in Section IV.D.4. were
                updated to correspond to the EPA's Method 27 and federal standards.
                ---------------------------------------------------------------------------
                 \58\ Control of Volatile Organic Compound Leaks from Gasoline
                Tank Trucks and Vapor Collection Systems, Appendix A, EPA-450/2-78-
                051. Dec. 1978.
                 \59\ See also 40 CFR 63.425(e).
                 \60\ Standards of Performance for Bulk Gasoline Terminals (40
                CFR part 60, subpart XX (August 18, 1983, last revised December 19,
                2003)).
                 \61\ National Emission Standards for Gasoline Distribution
                Facilities (Bulk Gasoline Terminals and Pipeline Breakout Stations)
                (40 CFR part 63 Subpart R (December 14, 1994, last revised April 6,
                2006)).
                 \62\ National Emission Standards for Hazardous Air Pollutants
                for Source Category: Gasoline Distribution Bulk Terminals, Bulk
                Plants, and Pipeline Facilities (40 CFR part 63, subpart BBBBBB
                (January 10, 2008, last revised January 24, 2011)).
                 \63\ National Emission Standards for Hazardous Air Pollutants
                for Source Category: Gasoline Dispensing Facilities (40 CFR part 63,
                subpart CCCCCC (January 10, 2008, last revised January 24, 2011)).
                ---------------------------------------------------------------------------
                 Under CAA section 110(l), the EPA cannot approve a SIP revision
                that interferes with any requirement concerning attainment, reasonable
                further progress, or any other applicable requirement of the Act. We
                propose to find that the revisions to Section IV.D. comply with section
                110(l) because the revisions are limited to updating the pressure
                vacuum test and values to be consistent with more recent EPA
                regulations for gasoline tank trucks and vapor collection systems, and
                the changes do not weaken the SIP.
                 We propose to find that the revisions in Part B are consistent with
                gasoline transport truck, terminal, and service station control and
                testing requirements of current NSPS and NESHAP standards and that
                approval of the submittal would comply with CAA Sections 110(l) and
                193. We therefore propose to approve the revisions in Part B.
                c. Part C
                 The revisions add a new Part C heading encompassing Sections I, II,
                III, IV, V (previously Reg. 7, Sections IX-XI, XIII, XIV) and
                appendixes D and E (formerly appendixes D and F). Part C regulates
                surface coating, solvents, asphalt, graphic arts and printing, and
                pharmaceuticals. The revisions also include renumbering and updates to
                Parts and Sections referenced throughout Part C, and adds a new
                categorical rule regulating VOC emissions from and establishing RACT
                for general solvent use in Section II.F.
                 Section II.F. addresses VOC emissions from sources with a potential
                to emit 50 tons per year of VOC and with solvent use emissions greater
                than or equal to two tons per year in the DMNFR Area. Section II.F.3.
                sets forth work practice requirements including covering containers,
                proper disposal of solvent waste, and the use of good air pollution
                practices such as the use of low/no VOC solvent if possible, using only
                amounts needed, submerged fill pipes, closed loop systems, and
                maintaining operations to be leak free. Section II.F.4. requires
                operations that use solvents with uncontrolled actual VOC emissions
                greater than or equal to 25 tons per year to reduce emissions by 90%.
                Sections II.F.5. and 6. set forth monitoring and recordkeeping
                requirements. Records must be maintained for a minimum of two years.
                Sources subject to Section II.F.4. requirements are also subject to
                additional control requirements, monitoring, performance testing, and
                recordkeeping requirements for general solvent use operations.
                 We propose to find that the provisions meet CAA and RACT
                requirements, and that they strengthen the SIP. We therefore propose to
                approve the changes in Part C.
                d. Part D
                 The revisions add a new Part D. heading for Sections I, II, and III
                (previously Reg. 7, Sections XII, XVII, and XVIII), and new Sections IV
                and V.\64\ Part D regulates oil and natural gas operations. The
                revisions also include renumbering and updates to Parts and Sections
                referenced throughout Part D, establishing a storage tank control
                threshold in lieu of the current system-wide control strategy,
                strengthening storage tank monitoring requirements, aligning related
                recordkeeping and reporting, and other SIP cleanup and strengthening
                measures.
                ---------------------------------------------------------------------------
                 \64\ Parts of the submission, including all of new Sections IV
                and V, are State Only requirements. We therefore will not be acting
                on these Sections. The State Only provisions are excluded from the
                list of provisions that we are acting on in Table 5.
                ---------------------------------------------------------------------------
                (i) Section I.A.
                 Section I.A. contains applicability provisions for Part D. The
                revisions to Section I.A. streamline and clarify sources subject to
                Part D and remove the exemption associated with the system-wide control
                program for owners or operators of condensate tanks with total actual
                uncontrolled VOC emissions less than 30 tpy (previously Section
                XII.A.7.).
                (ii) Sections I.B. and I.C.
                 Section I.B. contains definitions applicable to Part D. A new
                definition for ``commencement of operation'' was added for consistency
                with Regulation Number 3 and for clarity as to the applicability of
                other control requirements. New definitions for ``intermediate
                hydrocarbon liquid,'' ``produced water,'' ``storage tank,'' and
                ``storage vessel'' were also added. The definitions are clear,
                straightforward, accurate.
                 Section I.C. contains general provisions for Part D. Section I.C.2.
                specifies how operators must calculate emissions and emission
                reductions to demonstrate compliance with control requirements. The
                revisions in Section I.C.2.a.(iv) expand current provisions to tanks
                storing produced water or hydrocarbon liquids other than condensate.
                (iii) Section I.D.
                 Section I.D. contains provisions for storage tank emissions
                controls. In 2004 the Commission adopted the initial system-wide
                control strategy, which required operators to reduce emissions from
                their system of condensate tanks. The ``system'' was composed of
                condensate tanks with uncontrolled actual VOC emissions equal to or
                greater than two tpy, and allowed operators to decide which tanks to
                control if emissions from the ``system'' were reduced by specified
                percentages. The revisions in Section I.D. replace the system-wide
                control strategy with an individual storage tank control strategy in
                Section I.D.3. Operators in the DMNFR Area were required to install
                controls on storage tanks with uncontrolled actual VOC emissions equal
                to or greater than four tpy by May 1, 2020. The control requirements in
                Section I.D. were expanded to include crude oil and produced water
                tanks. According to the Division, this will
                [[Page 32667]]
                result in more tanks being controlled.\65\ Section I.D.3.a.(i) requires
                that storage tanks with uncontrolled actual emissions of VOC equal to
                or greater than four tons per year collect and control emissions from
                each storage tank by routing emissions to and operating air pollution
                control equipment that achieves a VOC control efficiency of 95%;
                combustion devices must have a design destruction efficiency of at
                least 98% for VOC unless authorized by permit before March 1, 2020.
                Section I.D.3.c. requires that storage tanks below the four tpy
                threshold that increase emissions above the threshold must be in
                compliance within 60 days of the first date of the month in which the
                threshold was exceeded. The Commission has determined that the four tpy
                threshold and implementation timetable is cost-effective, technically
                feasible, and will ensure no backsliding as provided for in the Clean
                Air Act, Section 110(l).\66\
                ---------------------------------------------------------------------------
                 \65\ See pp. 592-593 of the May 13, 2020 submittal.
                 \66\ See p. 591 of the May 13, 2020 submission.
                ---------------------------------------------------------------------------
                 Colorado also submitted a provision for inclusion in the SIP that
                was previously state-only. Section I.D.2.a. requires that that
                operators of newly constructed tanks employ controls during the first
                90 days after the date of first production. The provision is proposed
                for inclusion in the SIP to avoid confusion as to whether compliance
                with the requirement can be considered a limitation upon a source's
                potential to emit for purposes of permitting.
                (iv) Section I.E.
                 Section I.E. contains provisions for monitoring of storage tanks
                and air pollution control equipment. Section I.E. was revised to apply
                the monitoring requirements for all storage tanks controlled pursuant
                to Section I.D., which will ensure monitoring of condensate tanks,
                crude oil, and produced water tanks on a weekly basis per Section
                I.E.2.c. The required inspections have also been updated to include
                elements that can impact the performance of well production facility
                equipment and reduce emissions including checking that burner trays are
                not visibly clogged, that pressure relief valves are properly sealed,
                and that vent lines are closed. Inspection documentation requirements
                in former Section XII.E.3. were removed and moved to Section
                I.F.2.c.(iii) in order to condense all recordkeeping requirements in
                Section I.F.
                (v) Section I.F.
                 Section I.F. contains provisions for storage tank recordkeeping and
                reporting. As a result of replacing the system-wide control strategy
                with the fixed control threshold in Section I.D., recordkeeping and
                reporting requirements for demonstrating compliance with Section I.D.
                were revised in Section I.F. Operators subject to the system-wide
                control strategy were given until August 31, 2020, to submit the report
                for the time period in 2020 during which the system-wide control
                strategy remained effective (i.e. January 1-April 30, 2020). Section
                I.F.2 contains the recordkeeping and reporting scheme for the tanks
                subject to the new four tpy control threshold provision. Under Sections
                I.F.2. and I.F.3., owners or operators of storage tanks subject to
                Section I.D.3. must maintain records and submit annual reports
                including information regarding inspections, calendar monthly VOC
                emissions, emission factors used, and the control efficiency of air
                pollution control equipment. Reports must be retained for a minimum of
                five years.
                (vi) Section I.L.
                 Section I.L. contains provisions for the DMNFR Area leak detection
                and repair program. Sections I.L.2.a. and I.L.2.b. revised language
                clarifies that applicability for leak inspections at well production
                facilities are based on rolling twelve-month emission totals and not a
                calendar year basis.
                (vii) Section II
                 Section II contains statewide controls for oil and gas operations.
                The majority of Section II consists of State Only requirements.
                However, the Commission submitted previous State Only revisions for
                inclusion in the SIP to Section II.C.1.b.(ii), which requires that
                operators of newly constructed tanks employ controls within 90 days of
                commencement of operation. Previous State Only requirements in Section
                II.G. were also submitted for inclusion in Colorado's SIP. The
                provisions require control of emissions coming off a separator after a
                well is newly constructed, hydraulically fractured, or recompleted.
                These emissions must be routed to a gas gathering line or controlled by
                air pollution control equipment. The provisions were submitted for
                inclusion in the SIP to clarify permitting compliance requirements in
                Reg. 3.
                 We propose to find that the revisions to Part D meet CAA and RACT
                requirements, and that they strengthen the SIP. We therefore propose to
                approve the changes in Part C.
                e. Part E
                 The revisions add a new Part E heading for Sections I, II, III, and
                IV (previously Reg 7, Sections XVI, XIX, and XX). Part E regulates
                emissions from combustion equipment at major sources of RACT. The
                revisions also include renumbering and updates to Parts and Sections
                referenced throughout Part E, add RACT requirements in Colorado's ozone
                SIP for 50 tpy major sources of VOC and/or NOX, and other
                cleanup and strengthening measures.\67\
                ---------------------------------------------------------------------------
                 \67\ The revisions to Sections II.A.1.b., II.A.4.a.(iii) and
                (iv), II.A.6.a.(ii), and II.A.6.b.(viii)(B) include the placeholder
                language [EFFECTIVE DATE OF THE RECLASSIFICATION] because the
                Commission approved the revisions before the EPA finalized
                reclassification of the DMNFR Area to Serious. The EPA finalized its
                reclassification of the Area on December 26, 2019. See Final rule,
                Finding of Failure To Attain and Reclassification of Denver Area for
                the 2008 Ozone National Ambient Air Quality Standard, 84 FR 70897.
                ---------------------------------------------------------------------------
                (i) Section II
                 Section II provisions control emissions from stationary and
                portable combustion equipment in the DMNFR area. Section II.A.1.b.
                expands the applicability of Section II requirements to stationary
                combustion equipment at major sources of NOX as of January
                27, 2020. New definitions were added in Section II.A.3. for ``ceramic
                kiln,'' ``dryer,'' and ``furnace'' to support the expanded combustion
                adjustment requirements in Section II.A.6. The definitions are clear,
                straightforward, and accurate.
                 Owners or operators of combustion equipment specified in Section
                II.A.1.b. must comply with emission limits in Section II.A.4. by July
                20, 2021. This date is consistent with the EPA's implementation
                deadline for RACT measures not tied to attainment.\68\ New Sections
                II.A.4.a.(iii) expands emission limits requirements for boilers over
                100 MMBtu/hr larger boilers and Section II.A.4.a.(iv) adds emission
                limits for boilers between 50 and 100 MMBtu/hr located at sources
                greater than or equal to 50 tpy of NOX. Applicability of
                combustion process adjustment requirements in Section II.A.6. was
                expanded to include individual pieces of combustion equipment at major
                sources of NOX under a Serious classification. The
                requirements of Section II.A.6.a.(ii) apply to boilers, duct burners,
                process heaters, stationary combustion turbines, stationary
                [[Page 32668]]
                reciprocating internal combustion engines, dryers, furnaces, and
                ceramic kilns that have uncontrolled actual NOX emissions
                equal to or greater than five tpy that existed at major sources of
                NOX as January 27, 2020. Sections II.A.6.(v)-(vii) expand
                combustion process adjustment requirements to dryers, furnaces, and
                ceramic kilns. Sections II.A.6.b.(viii)(A)-(C) clarify and expand
                combustion adjustment frequency requirements, including dates for
                initial combustion process adjustments.
                ---------------------------------------------------------------------------
                 \68\ Final Rule, Finding of Failure To Attain and
                Reclassification of Denver Area for the 2008 Ozone National Ambient
                Air Quality Standard, 84 FR 70897, 70900 (Dec. 26, 2019).
                ---------------------------------------------------------------------------
                 We propose to find that the revisions to Section II are consistent
                with CAA requirements, and that they strengthen the SIP.
                (ii) Section III
                 Section III provisions control emissions from specific major
                sources of VOC and/or NOX in the DMNFR area. Section
                III.B.1. establishes emission limits and associated monitoring,
                recordkeeping, and reporting (MRR) requirements for stationary internal
                combustion engines at certain major sources to meet RACT. Section
                III.B.2. sets forth flare requirements and Section III.B.3. establishes
                MRR requirements for specific emission points at certain major sources
                to meet RACT. Section III.B.4. requires certain major sources to submit
                RACT analyses to the Division. We propose to find that the revisions to
                Sections III.B.1. through 4. strengthen the SIP and meet CAA
                requirements. We also propose to find that Sections III.B.1. through 2.
                establishes RACT requirements for certain major sources by
                incorporating federal regulations.
                 We propose to find that the revisions to Part E are consistent with
                CAA requirements, and that they strengthen the SIP. We therefore
                propose to approve the changes in Part E.
                VII. Proposed Action
                 For the reasons expressed above, the EPA proposes to approve
                revisions to Sections II, XII, and XVIII of Reg. 7 from the State's May
                14, 2018 and May 8, 2019 submittals and Parts A through E from the
                State's May 13, 2020 submission as shown in Table 5, except for those
                revisions we are not acting on as represented in Table 6. We are
                proposing to approve Colorado's determination that the above rules
                constitute RACT for the specific categories addressed in Tables 2 and
                3.
                 A comprehensive summary of the revisions in Colorado's Reg. 7
                organized by the EPA's proposed rule action, reason for proposed ``no
                action'' and submittal date are provided in Tables 5 and 6.
                 Table 5--List of Colorado Revisions to Reg. 7 That the EPA Proposes To
                 Approve
                ------------------------------------------------------------------------
                 Revised sections in May 14, 2018, May 8, 2019 and May 13, 2020
                 submittals proposed for approval
                -------------------------------------------------------------------------
                May 14, 2018 Submittal:
                 II.B, XII.A.2, XII.B.1.-XII.B.3., XII.B.6-XII.B.13, XII.B.16-
                 XII.B.21., XII.B.25., XII.C.1.d.-XII.C.1.e., XII.C.1.e.(iv),
                 XII.D., XII.F., XII.F.3.a.(i)-XII.F.3.a.(x), XII.F.5., XII.G.,
                 XII.G.1., XII.G.3., XII.G.4., XII.H.3., XII.H.6.a., XII.I., XII.J.,
                 XII.J.1, XII.J.1.a.-j., XII.J.2., XII.J.2.a.-e., XII.K., XII.K.1.,
                 XII.K.2., XII.K.2.a.-h(iv), XII.K.3., XII.K.3.a., XII.K.a.(i)-(vi),
                 XII.K.4., XII.K.5., XII.L., XII.L.1., XII.L.1.a.-b., XII.L.2.,
                 XII.L.2.a.-d., XII.L.3., XII.L.3.a.-c., XII.L.4., XII.L.4.a.-e.,
                 XII.L.5., XII.L.5.a.-c., XII.L.6., XII.L.6.a.-i., XII.L.7.,
                 XII.L.7.a.-g., XII.L.8., XII.L.8.a., XII.L.8.a.(i)-(ii),
                 XII.L.8.a.(ii)(A)-(I), XII.L.8.a.(iii), XII.L.8.a.(iv),
                 XII.L.8.a.(v), XVIII, XVIII.B.1..-B.3., XVIII.B.5.-11., XVIII.C.-
                 XVIII.C.2.c.(ii), XVIII.D.-XVIII.D.2.b., and XVIII.E.-XVIII.E.2.c.
                May 8, 2019 Submittal:
                 XII.B.12., XII.B.13., XII.B.20., XIII.G.3., XII.J.1.j., XII.J.2.e.,
                 XII.K.5., XVIII.B.1., XVIII.B.5., XVIII.B.7.-9., and XVIII.D.1.b.
                May 13, 2020 Submittal:
                 Outline of Regulation, PART A, I.A.1.c., I.B.1.c., I.B.2.h., II.B.,
                 PART B, I.-I.C., II.--B., III.-III.B., IV.- IV.D.4.e., V.-V.C., VI.-
                 VI.C.4.c.(ii), VII.- VII.B.2.b., Appendix B, V., VIII., Appendix
                 C, PART C, I.- I.O.5.a.(v), II.- II.F.6.j., III.- III.B.3.b., IV-
                 IV.B.5.c.(iii)(B), V.-V.C.1., Appendix D (renumbering), PART D, I.-
                 I.B.27., I.B.29.-I.C.e., I.C.1.e.(iii)-(iv), I.C.2.- I.C.2.a.(v),
                 I.D.- I.D.3.a.(i), I.D.3.b.- I.D.3.b.(iii), I.D.3.b.(v),
                 I.D.3.b.(vii), I.D.3.b.(ix), I.D.4.- I.E.1.a., I.E.2.-
                 I.E.2.c.(ii), I.E.2.c.(iv)- I.E.2.c.(viii), I.F.-I.F.1.d.,
                 .I.F.1.g.-I.F.1.g.(xii), I.F.1.h.- I.F.2.a., I.F.2.c.-
                 I.F.2.c.(vi), I.F.3., I.F.3.a., I.F.3.c.- I.F.3.c.(i)(C), I.G.-
                 I.H.1., I.H.3.-I.L.8.a.(v)., II.C., II.C.1., II.C.1.b.(ii)-(B),
                 II.F, III.-III.B.3., III.B.5., III.B.7.-III.C.2.c.(ii), III.D.-
                 III.D.2.b., III.D.3.b., III.E.-III.E.2.c., PART E, I.-I.D., I.D.3.-
                 I.D.3.a.(ii), II.-II.A.4.b., II.A.4.b.(ii)-II.A.4.c., II.A.4.e.-
                 II.A.8.b.(i), III.-III.B.4.n., IV.-IV.A.7.c.
                ------------------------------------------------------------------------
                 Table 6--List of Colorado Revisions to Reg. 7 That the EPA Is Proposing
                 To Take No Action on
                ------------------------------------------------------------------------
                 Reason for proposed ``no
                 Revised sections action''
                ------------------------------------------------------------------------
                May 14, 2018 Submittal:
                 XII.A.1., XII.A.1.c., XII.A.1.d.(ii), Superseded by May 13,
                 XII.A.2.-7., XII.B., XII.B.4.-5., 2020 submittal.
                 XII.B.12.-14., XII.B.22.-24., XII.C.,
                 XII.C.1.a., XII.C.1.e.(i)-(ii),
                 XII.C.1.f.-(ii), XII.D., XII.D.1.,
                 XII.D.2.a.-(i), XII.D.2.a.(vi)-(vii),
                 XII.E., XII.E.2.c., XII.F., XII.F.4..
                May 14, 2018 Submittal:
                 XVIII.B.4 \69\........................... State requested this be
                 ``state only''
                 definition.\70\
                May 13, 2020 submittal:
                 II.A.4.d.-(i)............................ Provision not previously
                 approved in the SIP.
                ------------------------------------------------------------------------
                VIII. Incorporation by Reference
                 In this document, the EPA is proposing to include regulatory text
                in an EPA final rule that includes incorporation by reference. In
                accordance with requirements of 1 CFR 51.5, the EPA is proposing to
                incorporate by reference Colorado AQCC Regulation 7 pertaining to the
                control of ozone via ozone precursors and control of hydrocarbons vial
                oil and gas emissions discussed in section VI of this preamble. The EPA
                has made, and will continue to make, these materials generally
                available through www.regulations.gov and at the EPA Region 8 Office
                (please contact the person identified in the FOR FURTHER
                [[Page 32669]]
                INFORMATION CONTACT section of this preamble for more information).
                ---------------------------------------------------------------------------
                 \69\ Revised Section III.B.4.
                 \70\ See March 1, 2021 email and attached letter from Colorado
                on ``Revised Pneumatics SIP Revisions Justification'' and May 3,
                2021 email from Leah Martland, Colorado Air Pollution Control
                Division (contained within the docket). The definition for
                ``enhanced response'' is in reference to the State Only pneumatics
                find and fix program and thus not applicable to SIP provisions.
                ---------------------------------------------------------------------------
                IX. Statutory and Executive Order Reviews
                 Under the CAA, the Administrator is required to approve a SIP
                submission that complies with the provisions of the Act and applicable
                Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
                reviewing SIP submissions, the EPA's role is to approve state choices,
                provided that they meet the criteria of the CAA. Accordingly, this
                action merely proposes to approve state law as meeting Federal
                requirements and does not impose additional requirements beyond those
                imposed by state law. For that reason, this action:
                 Is not a ``significant regulatory action'' subject to
                review by the Office of Management and Budget under Executive Orders
                12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21,
                2011);
                 Does not impose an information collection burden under the
                provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
                 Is certified as not having a significant economic impact
                on a substantial number of small entities under the Regulatory
                Flexibility Act (5 U.S.C. 601 et seq.);
                 Does not contain any unfunded mandate or significantly or
                uniquely affect small governments, as described in the Unfunded
                Mandates Reform Act of 1995 (Pub. L. 104-4);
                 Does not have federalism implications as specified in
                Executive Order 13132 (64 FR 43255, August 10, 1999);
                 Is not an economically significant regulatory action based
                on health or safety risks subject to Executive Order 13045 (62 FR
                19885, April 23, 1997);
                 Is not a significant regulatory action subject to
                Executive Order 13211 (66 FR 28355, May 22, 2001); and
                 Is not subject to requirements of section 12(d) of the
                National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
                note) because application of those requirements would be inconsistent
                with the CAA.
                 In addition, the SIP is not approved to apply on any Indian
                reservation land or in any other area where the EPA or an Indian tribe
                has demonstrated that a tribe has jurisdiction. The proposed rule does
                not have tribal implications and will not impose substantial direct
                costs on tribal governments or preempt tribal law as specified by
                Executive Order 13175 (65 FR 67249, November 9, 2000).
                 Executive Order 12898 (Federal Actions To Address Environmental
                Justice in Minority Populations and Low-Income Populations, 59 FR 7629,
                February 16, 1994) directs federal agencies to identify and address
                ``disproportionately high and adverse human health or environmental
                effects'' of their actions on minority populations and low-income
                populations to the greatest extent practicable and permitted by law. We
                are proposing to approve state rules as meeting the CAA standard for
                RACT, which EPA has defined as the lowest emission limitation that a
                particular source is capable of meeting by the application of control
                technology that is reasonably available considering technological and
                economic feasibility. Accordingly, we propose to determine that this
                rule, if finalized, will not have disproportionately high or adverse
                human health or environmental effects on minority or low-income
                populations.
                List of Subjects in 40 CFR Part 52
                 Environmental protection, Air pollution control, Carbon monoxide,
                Greenhouse gases, Incorporation by reference, Intergovernmental
                relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting
                and recordkeeping requirements, Sulfur oxides, Volatile organic
                compounds.
                 Authority: 42 U.S.C. 7401 et seq.
                 Dated: June 11, 2021.
                Debra H. Thomas,
                Acting Regional Administrator, Region 8.
                [FR Doc. 2021-12875 Filed 6-21-21; 8:45 am]
                BILLING CODE 6560-50-P
                

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