Air Quality State Implementation Plans; Approvals and Promulgations: Colorado; RACT Requirements for the 2008 8-Hour Ozone Standard for the Denver Metro/North Front Range[...]

Air Plan Approval; Colorado; RACT Requirements for the 2008 8-Hour Ozone Standard for the Denver Metro/North Front Range Nonattainment Area

SUPPLEMENTARY INFORMATION:

Throughout this document wherever "we," "us," or "our" is used, we mean the EPA.

I. What action is the EPA proposing to take?

As explained in section V., below, the EPA is proposing to approve various Colorado SIP provisions that the State submitted on April 2, 2025, that address reporting requirements for certain source categories. The EPA is also proposing to approve organizational SIP revisions, specifically the relocation of existing portions of Colorado's Reg. 7 into new standalone regulations, which were submitted by the State on May 23, 2024.

On May 9, 2023, the EPA finalized approval, conditional approval, limited approval, and limited disapproval of different aspects of multiple SIP submittals revising Reg. 7 that were submitted between 2018 through 2022. ⁽¹⁾ Of relevance to this proposed action, the EPA finalized a limited disapproval with respect to the adequacy of the reporting requirements associated with certain provisions identified in the May 9, 2023 final action. ⁽²⁾

On May 3, 2024, the State of Colorado resubmitted portions of the prior SIP submissions that were the subject of the limited disapproval and also submitted a letter committing to undertake additional steps to improve reporting requirements and access to compliance information, and to clarify existing SIP reporting requirements (Commitment Letter). ⁽³⁾ Specifically, in the Commitment Letter, the State committed to submit SIP revisions to the EPA by May 31, 2025 that would add additional reporting provisions for the following source categories: (1) metal parts and metal products coatings; (2) wood products coatings; (3) combustion equipment at major sources, and; (4) foam manufacturing. ⁽⁴⁾

On August 6, 2024, the EPA proposed to conditionally approve the resubmitted SIP based on the State's commitment to add reporting requirements for these four source categories as described in the Commitment Letter. ⁽⁵⁾ The EPA proposed to find that the State's commitment, if fulfilled, would address the deficiencies identified in the May 9, 2023 rulemaking that were the basis for the limited disapproval. ⁽⁶⁾ The EPA simultaneously issued an interim final determination on August 6, 2024, which deferred the imposition of sanctions that were triggered by the EPA's May 9, 2023 limited disapproval. ⁽⁷⁾

On April 2, 2025, Colorado submitted to the EPA a SIP revision intended to fulfill the State's commitments in the Commitment Letter that was the basis for the EPA's proposed conditional approval on August 6, 2024. The EPA is now proposing to approve the April 2, 2025 submittal, as discussed further below. ⁽⁸⁾ This proposed approval supersedes the EPA's previous proposed conditional approval, as the EPA is now proposing full approval of all the provisions that we previously proposed to conditionally approve.

II. Background

A. 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). ⁽⁹⁾ 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 met 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. ⁽¹⁰⁾ Effective July 20, 2012, the EPA designated any area as nonattainment that caused or contributed to a violation of the 2008 8-hour ozone NAAQS based on the three most recent years (2008-2010) of air monitoring data. ⁽¹¹⁾

Ozone nonattainment areas are initially classified based on the severity of their ambient 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. ⁽¹²⁾ In our July 20, 2012 action, the EPA initially designated the Denver-Boulder-Greeley-Ft. Collins-Loveland, Colorado area as nonattainment and classified the area as Marginal. ⁽¹³⁾ The nonattainment area includes Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, and Jefferson Counties and portions of Larimer and Weld Counties. The EPA refers to this nonattainment area as the Denver Metro/North Front Range (DMNFR) for ease of reference. ⁽¹⁴⁾ The DMNFR area did not attain the 2008 8-hour ozone NAAQS by the applicable Marginal area attainment deadline, and accordingly was reclassified as Moderate. ⁽¹⁵⁾ After not attaining the 2008 ozone NAAQS for subsequent attainment dates, the area was reclassified to Serious, and then to Severe nonattainment status. ⁽¹⁶⁾

B. The EPA's May 9, 2023 Final Rule

On May 9, 2023, the EPA took final action approving portions of the 2008 8-hour ozone Serious area attainment plan for the DMNFR area submitted by the State of Colorado on March 22, 2021, and portions of additional SIP submissions made by the State related to those requirements on May 8, 2019, May 13, 2020, March 22, 2021, May 18, 2021, and May 20, 2022. ⁽¹⁷⁾ The State made these SIP submissions to meet Serious ozone nonattainment plan requirements for the DMNFR area. Specifically, the submissions address CAA section 182(b)(2) RACT requirements for certain source categories and adopt volatile organic compounds (VOC) standards for consumer products and architectural and industrial maintenance coatings in the DMNFR area. In the May 9, 2023 action, the EPA also finalized a limited approval and limited disapproval of parts of the SIP submissions made on May 14, 2018, May 13, 2020, March 22, 2021, May 18, 2021, and May 20, 2022, addressing RACT for certain source categories, ⁽¹⁸⁾ and finalized a limited conditional approval and limited disapproval of specific provisions intended to meet RACT requirements for other source categories. ⁽¹⁹⁾

The limited disapproval portions of the May 9, 2023 final rule were based on the EPA's determination that although the rules largely met RACT requirements with respect to stringency, they lacked provisions necessary to satisfy CAA section 110 enforceability requirements and related regulatory reporting requirements under 40 CFR 51.211.

On July 10, 2023, the State submitted a Petition for Reconsideration asking the EPA to reconsider the limited disapproval portions of the May 9, 2023 final rule. ⁽²⁰⁾ The EPA responded to the Petition for Reconsideration in a letter dated August 31, 2023, informing the State that the EPA was granting the petition as to the limited disapproval portions of the May 9, 2023 final rule. ⁽²¹⁾ Through the reconsideration process, Colorado had the opportunity to clarify and explain more fully how certain state regulations do provide for adequate enforceability, to inform the EPA of various actions taken by the Colorado Air Pollution Control Division (Division) to enhance access to records and information, and to consider what changes to existing regulations would improve reporting requirements to address the May 9, 2023 limited disapproval.

C. The EPA's August 6, 2024 Proposed Rule

On May 3, 2024, the State of Colorado resubmitted portions of the prior SIP submissions that were the subject of the May 9, 2023 limited disapproval and also submitted the Commitment Letter, in which the State committed to undertake additional steps to improve access to regulatory compliance information and clarify existing SIP reporting requirements. ⁽²²⁾ Based on the additional information provided in the Commitment Letter, on August 6, 2024, the EPA proposed to approve Colorado's Reg. 7 and Reg. 21 with respect to the adequacy of reporting requirements for storage tank emission controls, storage tank and wet seal centrifugal compressor control device testing, consumer products, and architectural and industrial maintenance (AIM) coatings. ⁽²³⁾ In that action, the EPA also proposed to conditionally approve the adequacy of reporting requirements for metal parts and metal products coatings, wood products coatings, combustion equipment at major sources, and foam manufacturing based on the State's commitment to make further revisions to the reporting requirements or demonstrate the sufficiency of existing reporting for these specific rules, and to submit those revisions to the EPA for approval into the SIP by May 31, 2025.

III. Summary of Colorado's SIP Submittals

May 23, 2024 and April 2, 2025 SIP Revisions

The State of Colorado submitted formal SIP revisions on May 23, 2024 and April 2, 2025, which included administrative and substantive revisions to Reg. 7, 25, and 26. These SIP revisions included modifications to existing rules related to RACT and administrative reorganization of existing regulations.

The May 23, 2024 SIP submission substantially reorganizes Reg. 7. Of relevance to this proposed action, Reg. 7 was retitled from "Control of Ozone via Ozone Precursors and Control of Hydrocarbons via Oil and Gas Emissions (Emissions of Volatile Organic Compounds (VOC) & Nitrogen Oxides (NO _X ))" to "Control of Emissions from Oil and Gas Emissions Operations." Additionally, Reg. 7, Part C was relocated to the newly established Reg. 25, "Control of Emissions from Surface Coating, Solvents, Asphalt, Graphic Arts and Printing, and Pharmaceuticals," and Reg. 7, Part E was relocated to the newly established Reg. 26, "Control of Emissions from Engines and Major Stationary Sources."  ⁽²⁴⁾ Table 1 details the provisions the EPA is proposing to approve in this action, which includes the relocation of a portion of Reg. 7 into Reg. 25 as submitted May 23, 2024.

The April 2, 2025 SIP submission also revises Reg. 7, 25, 26 and 27. Of relevance to this proposed action, this submittal makes the following revisions to Reg. 25, Part B: adds reporting requirements for manufactured metal parts and metal products at section I.L.6., and for wood products coatings at section I.O.6. This submittal also revises Reg. 26, Part B by adding a reporting requirement for combustion equipment rules at section II.A.8.c. and a reporting requirement for foam manufacturing at section V.A.8.b. The submittal contains additional revisions that the EPA is not proposing to act on here. These revisions were either addressed in the EPA's April 9, 2026 final rulemaking action, ⁽²⁵⁾ or will be addressed in a separate future rulemaking.

IV. Procedural Requirements

The CAA requires that states meet certain procedural requirements before submitting a SIP revision to the EPA, including the requirement that states adopt SIP revisions after reasonable notice and public hearing. ⁽²⁶⁾ Colorado adopted the May 23, 2024 submittal following a January 21, 2023 notice of rulemaking in the Denver Post and an April 20, 2023 rulemaking hearing. ⁽²⁷⁾ Colorado adopted the April 2, 2025 submittal following an August 17, 2024 notice of rulemaking in the Denver Post and a December 18-20, 2024 rulemaking hearing. ⁽²⁸⁾ The CAA also requires that the EPA cannot approve a SIP revision if the revision would interfere with any applicable requirement concerning attainment and reasonable further progress toward attainment of the NAAQS, or any other applicable requirement of the Act. ⁽²⁹⁾ As discussed in section V., below, the Colorado SIP provisions that the EPA is proposing to approve in this action do not interfere with any applicable requirements of the Act.

V. The EPA's Evaluation of Colorado's SIP Submissions

In this proposed action, we are evaluating Colorado's April 2, 2025 SIP submittal, which is intended to fulfill the State's commitment to add reporting requirements in response to the May 9, 2023 limited disapproval. Our proposed approval of the SIP provisions in this action does not alter our previous determination that these rules implement RACT with respect to the source categories covered by the rules. It solely addresses the specified deficiencies in reporting requirements that were identified in the limited disapproval. ⁽³⁰⁾ The EPA is taking comment on today's proposal for 30 days and will only be considering comments on this proposal that address our proposed approval with respect to reporting requirements for metal parts and metal products coatings, wood products coatings, combustion equipment at major sources, and foam manufacturing. This proposed approval of these provisions supersedes the proposed conditional approval of the State's Commitment Letter in the August 6, 2024 proposal. However, this proposed action has no bearing on the provisions that the EPA proposed to fully approve in the August 6, 2024 proposal. ⁽³¹⁾ When the EPA finalizes action on this proposal, we also intend to finalize action on the SIP provisions that we proposed to fully approve in our August 6, 2024 proposal.

Table 1, below, details the revisions from the two Colorado SIP submittals that the EPA is proposing to approve. The revisions in each submittal that the EPA is not proposing action on here will be addressed in later rulemakings. ⁽³²⁾

A. Reorganization of Regulation 7 Into Regulation 25

As noted in section III.A. above, on May 23, 2024, Colorado submitted revisions that substantially reorganized Reg. 7 by relocating sections of Reg. 7 into Reg. 25 and Reg. 26. As part of Colorado's May 23, 2024 submittal, Reg. 7, Part E, section II. was relocated to the newly established Reg. 26, Part B, section II., and Reg. 7, Part E, section V. was relocated to the newly established Reg. 26, Part B, section V. The EPA proposed approval of the relocation of Reg. 7 into Reg. 26 Parts A and B on June 18, 2025. ⁽³³⁾ In this proposed action, the EPA is proposing to approve the relocation of Reg. 7, Part C, sections I.L. (Manufactured Metal Parts and Metal Products) and I.O. (Wood Products Coating) to Reg. 25, Part B, sections I.L. and I.O., as submitted May 23, 2024 (see table 1). These organizational revisions do not involve substantive changes to any of the reorganized regulations and are not specific to the reporting requirements evaluated in this action, but the EPA is proposing to approve them here because subsequent regulatory revisions in Colorado's April 2, 2025 SIP submittal, that the EPA is addressing in this action, concern the newly established Reg. 25.

B. Metal Parts and Metal Product Rules, Reg. 25, Part B, Section I.L

Reg. 7, Part C, section I. contains existing rules for surface coating operations. ⁽³⁴⁾ As stated, section I.L. was relocated to the newly established Reg. 25, Part B, section I.L. as part of Colorado's May 23, 2024 submission, and the EPA is proposing to approve this relocation. Section I.L. includes metal parts and metal products rules and applies to major and minor sources of VOC in the DMNFR Area. The rules require sources to use products that comply with VOC content limits listed in tables 1 and 2 of the regulation. ⁽³⁵⁾ The recordkeeping provisions in Reg. 25, Part B, section I.L.5. require applicable records to be maintained for five years and made available to the Division upon request.

In the April 2, 2025 submittal, Colorado incorporated additional reporting requirements for the metal parts and metal products source category into Reg. 25, Part B, section I.L.6. that require sources to submit an annual report that includes a demonstration that products used during the calendar year comply with the applicable VOC content limits. ⁽³⁶⁾ This information is made available through the Division's Public Records Portal. ⁽³⁷⁾ Accordingly, the EPA is proposing to find that the April 2, 2025, revisions to Reg. 25, Part B, section I.L., specifically the addition of section I.L.6., I.L.6.a. and I.L.6.b., address the CAA section 110 and 40 CFR 51.211 regulatory requirements for enforceability.

C. Wood Products Coating Rules, Reg. 25, Part B, Section I.O

Reg. 7, Part C., section I.O. includes existing wood products coating rules applicable to major stationary sources of VOC emissions in the DMNFR Area. ⁽³⁸⁾ As stated, Reg. 7, Part C section I.O. was relocated to the newly established Reg. 25, Part B, section I.O. as part of Colorado's May 23, 2024 submission, and the EPA is proposing to approve this relocation. The rules require sources to use products that comply with the VOC content limits in section I.O.3. The recordkeeping provisions in section I.O.5. require applicable records to be maintained for five years and to be made available to the Division upon request.

Colorado's April 2, 2025 SIP revisions require sources to submit a semi-annual report documenting that the products used during the previous semi-annual reporting period comply with the VOC content limits in Reg. 25, Part B, section I.O.3. ⁽³⁹⁾ This information is made available through the Division's Public Records Portal. Accordingly, the EPA is proposing to find that the April 2, 2025 revisions to Reg. 25, Part B, section I.O., specifically the addition of section I.O.6., address the CAA section 110 and 40 CFR 51.211 regulatory requirements for enforceability.

D. Combustion Equipment Rules, Reg. 26, Part B, Section II

Reg. 26, Part B, section II. includes existing requirements for combustion equipment located at major sources of NO _X emissions in the DMNFR Area. ⁽⁴⁰⁾ This section requires sources to comply with NO _X emission limits and combustion tuning requirements. The recordkeeping provisions in SIP-approved Reg. 26, Part B, section II.A.7. require that affected sources keep records for a period of five years and make them available to the Division upon request.

The State's April 2, 2025 SIP revisions require the relevant sources to submit a semi-annual report documenting compliance with the combustion process adjustment requirements in Reg. 26, Part B, section II.A.6. ⁽⁴¹⁾ The reports must include information with respect to sources not also subject to continuous monitoring or performance testing such that the information provides for evaluation of compliance with all of the applicable SIP emission limitations in Reg. 26, Part B, section II. This information is accessible through the Division's Public Records Portal. Accordingly, the EPA is proposing to approve the State's April 2, 2025 revision adding section II.A.8.c. to Reg. 26, Part B, because it addresses the CAA section 110 and 40 CFR 51.211 regulatory requirements for enforceability.

E. Foam Manufacturing Rules, Reg. 26, Part B, Section V

Reg. 26, Part B., section V. includes existing requirements for foam manufacturing operations located at major sources of VOC emissions in the DMNFR Area. ⁽⁴²⁾ The rules require sources to comply with VOC emission limits in section V.A.4. The recordkeeping provisions in section V.A.7. require that affected sources keep records for a period of five years and make them available to the Division upon request.

The State's April 2, 2025 SIP revisions require sources to submit a semi-annual report documenting compliance with the VOC emission limits in section V.A.4. ⁽⁴³⁾ This information is accessible through the Division's Public Records Portal. ⁽⁴⁴⁾ Accordingly, the EPA is proposing to approve the State's April 2, 2025 revision adding section V.A.8.b. to Reg. 26, Part B, because it addresses the CAA section 110 and 40 CFR 51.211 regulatory requirements for enforceability.

VI. Proposed Action

For the reasons explained above, the EPA proposes to approve the relocation of Reg. 7, Part C, sections I.L. and I.O. to Reg. 25, Part B, sections I.L. and I.O. as detailed in Colorado's May 23, 2024 SIP submittal. The EPA also proposes to approve Colorado's April 2, 2025 SIP revisions to metal parts and metal products coatings rules in Reg. 25, Part B, section I.L.6.; wood products coatings rules in Reg. 25, Part B, section I.O.6.; rules for combustion equipment at major sources in Reg. 26, Part B, section II.A.8.c.; and rules for foam manufacturing operations in Reg. 26, Part B, section V.A.8.b. The EPA is soliciting public comments on the proposed action and our rationale for the proposed action. The EPA will accept comments from the public on this proposal for the next 30 days and will consider comments before taking final action. In finalizing action on this proposal as well as the August 6, 2024 proposal, the EPA intends to respond to: (1) the comments that may be submitted concerning this proposal that address our proposed approval with respect to reporting requirements for metal parts and metal products coatings, wood products coatings, combustion equipment at major sources, and foam manufacturing; and (2) the public comments that were already submitted with respect to the proposed approval aspect of our August 6, 2024 proposal, which is not superseded by this proposal and for which the EPA is not soliciting additional comments in this action.

VII. 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 Air Quality Control Commission Reg. 25 pertaining to the "Control of Emissions from Surface Coating, Solvents, Asphalt, Graphic Arts and Printing, and Pharmaceuticals," Reg. 26 pertaining to the "Control of Emissions from Engines and Major Stationary Sources" and Reg. 7 pertaining to the "Control of Ozone via Ozone Precursors and Control of Hydrocarbons via Oil and Gas Emissions (Emissions of Volatile Organic Compounds (VOC) & Nitrogen Oxides (NO _X ))" (as specified in sections III.A. and V.A. above). The EPA has made, and will continue to make, these materials generally available through https://www.regulations.gov and at the EPA Region 8 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

VIII. 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 Order 12866 (58 FR 51735, October 4, 1993);
• Is not an Executive Order 14192 (90 FR 9065, February 6, 2025) regulatory action because this action is not significant under Executive Order 12866;

• 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 subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a State program;
• 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. In those areas of Indian country, the 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).

[FR Doc. 2026-12543 Filed 6-22-26; 8:45 am]

BILLING CODE 6560-50-P

⁽¹⁾  Final rule, Air Plan Approval, Conditional Approval, Limited Approval and Limited Disapproval; Colorado; Serious Attainment Plan Elements and Related Revisions for the 2008 8-Hour Ozone Standard for the Denver Metro/North Front Range Nonattainment Area, 88 FR 29827.

⁽²⁾ Id. at table 2, 88 FR 29830.

⁽³⁾  "Resubmittal of SIP revisions following Reconsideration. EPA Docket Nos.: EPA-R08-OAR-2022-0632; EPA-R08-OAR-2022-0857; and FRL-10362-02-R8" commitment letter. Available in the docket for this action.

⁽⁴⁾ Id. In the Commitment Letter, Colorado also provided additional clarification to demonstrate the adequacy of existing reporting requirements related to the inspection and performance testing of storage tanks and centrifugal compressors as well as for the State's consumer product and Architectural and Industrial Maintenance (AIM) coating rules. This proposed approval does not cover those existing reporting requirements. Rather, the EPA proposed to approve those reporting requirements in our August 6, 2024 proposed approval. See 89 FR 63852.

⁽⁵⁾  89 FR 63852.

⁽⁶⁾ Id. Our August 6, 2024 proposed action also proposed approval of existing reporting requirements related to the inspection and performance testing of storage tanks and centrifugal compressors as well as for the consumer product and AIM coating rules based on the additional information provided by the State in its Commitment Letter. See 89 FR 63852. The EPA intends to take final action on these elements of the August 6, 2024 proposed action in the same final rulemaking document as the provisions covered by this proposed action.

⁽⁷⁾  89 FR 63818.

⁽⁸⁾  In this proposed action, instead of finalizing a conditional approval, the EPA is proposing approval. This allows the public another opportunity to comment on the adequacy of reporting requirements for the following source categories, based upon Colorado's April 2, 2025 submission: (1) metal parts and metal products coatings; (2) wood products coatings; (3) combustion equipment at major sources, and; (4) foam manufacturing.

⁽⁹⁾  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 80 FR 65292 (Oct. 26, 2015).

⁽¹⁰⁾  40 CFR 50.15(b).

⁽¹¹⁾  77 FR 30088 (May 21, 2012).

⁽¹²⁾  40 CFR part 50, appendix I.

⁽¹³⁾  77 FR at 30110. See 40 CFR 81.306.

⁽¹⁴⁾  The EPA acknowledges that the DMNFR nonattainment area more precisely refers to the expanded area designated nonattainment under the 2015 NAAQS, but uses the term here because it has been used in our past actions related to this one and for ease of reference.

⁽¹⁵⁾  81 FR 26697 (May 4, 2016).

⁽¹⁶⁾  84 FR 70897 (Dec. 26, 2019) and 87 FR 60926 (Oct. 7, 2022).

⁽¹⁷⁾  88 FR 29827, table 1, 29829-29830 (May 9, 2023).

⁽¹⁸⁾ Id. at 29830-29831, table 2 (listing portions subject to limited approval and limited disapproval), table 3 (RACT categories).

⁽¹⁹⁾ Id. at 29830-29831, table 3. All other portions of the May 9, 2023 final rule were effective as of June 8, 2023, and remain in effect.

⁽²⁰⁾  The July 10, 2023 petition for reconsideration is available in docket number EPA-R08-OAR-2023-0483, concerning the EPA's October 4, 2023 proposed action to stay the portion of the agency's May 9, 2023 limited disapproval relating to reporting requirements. 88 FR 68532 (Oct. 4, 2023). The proposed stay has not been finalized. The petition for reconsideration, as well as Colorado's August 3, 2023 amended petition for reconsideration, is also available in the docket for this proposed action: EPA-R08-OAR-2024-0225.

⁽²¹⁾ See letter from EPA Regional Administrator KC Becker to Colorado Attorney General Phil Weiser (Aug. 31, 2023), in the docket for this action.

⁽²²⁾ See footnote 3.

⁽²³⁾  89 FR 63852.

⁽²⁴⁾  May 23, 2024 SIP Submittal, "Submittal Letter to EPA_Regs 7, 24, 25, 26_signed." The letter is dated May 21, 2024, but the SIP was submitted to EPA on May 23, 2024. The May 23, 2024 SIP Submittal was deemed complete by operation of law on November 23, 2024.

⁽²⁵⁾  91 FR 17857.

⁽²⁶⁾  CAA section 110(a)(2), 42 U.S.C. 7410(a)(2).

⁽²⁷⁾ See May 23, 2024 SIP Submittal, "Denver Post Legal Ad," in the docket for this action.

⁽²⁸⁾ See April 2025 SIP Submittal, Document Set 1 of 2, "Denver Post Legal Ad," in the docket for this action.

⁽²⁹⁾  CAA section 110(l), 42 U.S.C. 7410(l).

⁽³⁰⁾  88 FR 29827 (May 9, 2023).

⁽³¹⁾ See 89 FR 63852 (August 6, 2024), where the EPA proposed to approve Colorado's Reg. 7 and Reg. 21 with respect to the adequacy of reporting requirements for storage tank emission controls, storage tank and wet seal centrifugal compressor control device testing, consumer products, and architectural and industrial maintenance (AIM) coatings.

⁽³²⁾  The EPA has previously approved certain revisions from these submittals in our April 9, 2026 final rule at 91 FR 17857.

⁽³³⁾  90 FR 25960.

⁽³⁴⁾  Reg. 7, Part C SIP-approved rules can be found at https://www.epa.gov/air-quality-implementation-plans/epa-approved-statutes-and-regulations-colorado-sip.

⁽³⁵⁾  April 2025 SIP Submittal, Document Set 1 of 2, "SBAP Adopted R25 (clean)" at 37-39.

⁽³⁶⁾  April 2025 SIP Submittal, Document Set 1 of 2, "Reg Language Adopted R25 (redline)" at 3.

⁽³⁷⁾  Colorado's Commitment Letter also lists other ways to access to reporting information. Colorado May 3, 2024 letter to EPA, at 2-3.

⁽³⁸⁾  Reg. 7, Part C SIP approved rules can be found at https://www.epa.gov/air-quality-implementation-plans/epa-approved-statutes-and-regulations-colorado-sip.

⁽³⁹⁾  April 2025 SIP Submittal, Document Set 1 of 2, "Reg Language Adopted R25 (redline)" at 4.

⁽⁴⁰⁾  As stated in section V.A., the EPA proposed approval of the relocation of Reg. 7 Part E to Reg. 26 Parts A and B from Colorado's May 23, 2024 submittal on June 18, 2025. 90 FR 25960. Reg. 7, Part E SIP approved rules can be found at https://www.epa.gov/air-quality-implementation-plans/epa-approved-statutes-and-regulations-colorado-sip.

⁽⁴¹⁾  April 2025 SIP Submittal, Document Set 1 of 2, "Reg Language Adopted R26 (redline)" at 18.

⁽⁴²⁾  As stated in section V.A., the EPA proposed approval of the relocation of Reg. 7 Part E to Reg. 26 Parts A and B from Colorado's May 23, 2024 submittal on June 18, 2025. 90 FR 25960. Reg. 7, Part E SIP-approved rules can be found at https://www.epa.gov/air-quality-implementation-plans/epa-approved-statutes-and-regulations-colorado-sip.

⁽⁴³⁾  April 2025 SIP Submittal, Document Set 1 of 2, "Reg Language Adopted R26 (redline)" at 19.

⁽⁴⁴⁾ See p. 2-3 of the Commitment Letter for a description of ways the public can access records and information.