Air Plan Disapproval; Colorado; Regional Haze Plan for the Second Implementation Period

<RULE> ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R08-OAR-2024-0607; FRL-12598-02-R8]</DEPDOC> <SUBJECT>Air Plan Disapproval; Colorado; Regional Haze Plan for the Second Implementation Period</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is disapproving a regional haze state implementation plan (SIP) revision submitted in 2022 by the State of Colorado under the Clean Air Act (CAA or Act) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. Colorado's 2022 regional haze SIP revision addresses the requirement that states revise their long-term strategies every implementation period to make reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas (Class I areas). We are disapproving Colorado's 2022 regional haze SIP revision pursuant to the CAA and regulatory regional haze requirements. The EPA is not taking final action at this time on a separate revision to Colorado's SIP that consolidates existing, previously approved regional haze provisions into the same regulation where Colorado's new, second planning period provisions are located. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This rule is effective on February 25, 2026. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> The EPA has established a docket for this action under Docket ID No. EPA-R08-OAR-2024-0607. All documents in the docket are listed on the <E T="03">https://www.regulations.gov</E> website. Although listed in the index, some information is not publicly available, <E T="03">e.g.,</E> CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and will be publicly available only in hard copy form. Publicly available docket materials are available through <E T="03">https://www.regulations.gov,</E> or please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section for additional availability information. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Jaslyn Dobrahner, Air and Radiation Division, EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver, Colorado 80202-1129, telephone number: (303) 312-6252; email address: <E T="03">dobrahner.jaslyn@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document “we,” “us,” and “our” means the EPA. <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. What is being addressed in this document?</FP> <FP SOURCE="FP-2">II. Background</FP> <FP SOURCE="FP-2">III. Summary and Analysis of Major Issues Raised by Commenters</FP> <FP SOURCE="FP-2">IV. Final Action</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. What is being addressed in this document?</HD> The EPA is disapproving a SIP revision submitted by the State of Colorado to the EPA on May 20, 2022, and supplemented on August 2, 2022, and June 23, 2023 (Colorado's 2022 regional haze SIP revision), addressing the requirements of the second implementation period of the RHR. <SU>1</SU> <FTREF/> The EPA is disapproving Colorado's 2022 regional haze SIP revision pursuant to CAA section 169A and regulatory regional haze requirements. Under CAA section 110(k)(3), the EPA can only approve a SIP revision if it meets all applicable requirements of the Act. <SU>2</SU> <FTREF/> If the EPA concludes that a SIP revision does not meet all applicable CAA requirements, then the EPA has the authority to fully disapprove that revision. <SU>3</SU> <FTREF/> The analysis in this notice explains the flaws with the unconsented source closure of Nixon Unit 1 at the Ray D. Nixon Power Plant and why it requires a full disapproval. We find that Colorado's 2022 regional haze SIP revision does not meet the requirements of CAA section 110(a)(2)(E)(i)  <SU>4</SU> <FTREF/> because Colorado did not provide necessary assurances that the unconsented source closure of Nixon Unit 1 at the Ray D. Nixon Power Plant would not result in a taking pursuant to the U.S. Constitution. <SU>5</SU> <FTREF/> After Colorado submitted its 2022 regional haze SIP revision to EPA, Nixon Unit 1 informed the State that it would not consent to closure and raised concerns about the lawfulness of forcing a closure and the impacts of such a closure on electricity supply in the State. Whenever a state learns that a source no longer intends to close as contemplated by the submitted SIP, it is incumbent on that state to take appropriate steps which could include revising or supplementing the SIP, withdrawal, or providing EPA with necessary assurances that the closure would not violate federal or state law. Under these circumstances and for the additional reasons set out below, the EPA need not and cannot simply defer to the State's position in their comment letter that “no action before EPA results in a taking” and therefore the 2022 regional haze SIP revision would not violate federal or state law, including the U.S. Constitution, the Colorado Constitution, and applicable provisions of the Act. <SU>6</SU> <FTREF/> <FTNT> <SU>1</SU>  On November 20, 2025, Colorado withdrew the SIP measures associated with the closure of Comanche Unit 2 that were initially included as part of Colorado's long-term strategy and found in Regulation Number 23, Part A, Section IV.F.1.d. Therefore, the SIP measures associated with the closure of Comanche Unit 2 are no longer part of Colorado's 2022 regional haze SIP revision. The post-proposal withdrawal of the enforceable closure deadline for Comanche Unit 2 is discussed where appropriate in this preamble and could not, under the circumstances, have been taken into account when the EPA issued the proposed rule on July 16, 2025. </FTNT> <FTNT> <SU>2</SU>  42 U.S.C. 7410(k)(3). </FTNT> <FTNT> <SU>3</SU>   <E T="03">Id.</E> </FTNT> <FTNT> <SU>4</SU>  42 U.S.C. 7410(a)(2)(E). </FTNT> <FTNT> <SU>5</SU>  Throughout this document and the response to comment (RTC) document, we extend “Nixon Unit 1” to also include the associated Nixon coal handling facility. </FTNT> <FTNT> <SU>6</SU>   <E T="03">See</E> Docket ID No. EPA-R08-OAR-2024-0607-0059 at 29-35. </FTNT> The EPA also finds that Colorado's 2022 regional haze SIP revision does not meet the requirements of CAA section 169A(b)(2)  <SU>7</SU> <FTREF/> and the RHR at 40 CFR 51.308(f) because the unconsented source closure of Nixon Unit 1 was included in Colorado's long-term strategy, rendering the long-term strategy similarly unapprovable. Without Colorado addressing the inclusion of an unconsented closure without the necessary assurances, the EPA cannot approve Colorado's long-term strategy. Therefore, consistent with CAA section 110(k)(3), the EPA is fully disapproving Colorado's 2022 regional haze SIP revision. <FTNT> <SU>7</SU>  42 U.S.C. 7410(a)(2)(E). </FTNT> We note that Colorado did not provide flexibility in its long-term strategy to take into account the possibility of changing circumstances that may impact whether a source consents to closure, including changes in electricity demand and supply. For example, Colorado's recent decision (after the State's public comment process and after the EPA issued the proposed rule) to withdraw source closure provisions  <SU>8</SU> <FTREF/> from the list of enforceable closure deadlines demonstrates not only the possibility, but the reality, that changing circumstances necessitated a more flexible strategy. <SU>9</SU> <FTREF/> Colorado did not address this issue in withdrawing the additional unit and did not revise and resubmit an updated long-term strategy. <FTNT> <SU>8</SU>  On November 20, 2025, Colorado withdrew the SIP measures associated with the closure of Comanche Unit 2 that were initially included as part of Colorado's long-term strategy and found in Regulation Number 23, Part A, Section IV.F.1.d. </FTNT> <FTNT> <SU>9</SU>  Further, although not included as a required closure in this rulemaking, the Department of Energy (DOE) issued an order under section 202(c) of the Federal Power Act on December 30, 2025, to take all measures necessary to ensure that Unit 1 of Craig Station in Craig, Colorado is available to operate. <E T="03">See https://www.energy.gov/documents/federal-power-act-section-202c-craig-order-no-202-25-14.</E> This authority requires DOE to find that an emergency exists related to heightened demand for, or a shortage in supply of, electricity and that the order will best meet the emergency and service the public interest. <E T="03">See</E> 16 U.S.C. 824a(c). </FTNT> Because the EPA is fully disapproving Colorado's 2022 regional haze SIP revision, a federal implementation plan (FIP) or an approved SIP revision will be required to satisfy CAA and regional haze rule requirements. <SU>10</SU> <FTREF/> The FIP or SIP revision will need to fully address the second implementation period regulatory requirements, including revisions to Colorado's long-term strategy and reasonable progress goals. The EPA further observes that upon Colorado's withdrawal of Commanche Unit 2's closure from Colorado's 2022 regional haze SIP revision, Colorado did not address the impact of the withdrawal on Colorado's previously submitted analysis of its reasonable progress goals as they relate to the Uniform Rate of Progress (URP). This will also need to be addressed in the FIP or SIP revision. <FTNT> <SU>10</SU>   <E T="03">See</E> 42 U.S.C. 7410(c). </FTNT> In this final rule, the EP ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 68k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━