Air Plan Approval; Michigan; Second Period Regional Haze Plan

<RULE> ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R05-OAR-2021-0577; FRL-12588-02-R5]</DEPDOC> <SUBJECT>Air Plan Approval; Michigan; Second Period Regional Haze Plan</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 approving the Regional Haze State Implementation Plan (SIP) revision submitted by the Michigan Department of Environment, Great Lakes, and Energy (EGLE) on August 23, 2021, and supplemented on July 24, 2025, as satisfying applicable requirements under the Clean Air Act (CAA) and EPA's Regional Haze Rule (RHR) for the program's second implementation period. EGLE's SIP submission addresses the requirement that States must periodically revise their long-term strategies for making 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. The SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. EPA is taking this action pursuant to sections 110 and 169A of the CAA. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This final rule is effective on October 6, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> EPA has established a docket for this action under Docket ID No. EPA-R05-OAR-2021-0577. 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">i.e.,</E> Confidential Business Information (CBI), Proprietary Business Information (PBI), 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 either through <E T="03">https://www.regulations.gov</E> or at the Environmental Protection Agency, Region 5, Air and Radiation Division, 77 West Jackson Boulevard, Chicago, Illinois 60604. This facility is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding Federal holidays. We recommend that you telephone Matt Rau, at (312) 886-6524 before visiting the Region 5 office. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Matt Rau, Air and Radiation Division (AR-18J), Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, (312) 886-6524, <E T="03">rau.matthew@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA. This supplementary information section is arranged as follows: <EXTRACT> <FP SOURCE="FP-2">I. Background</FP> <FP SOURCE="FP-2">II. Public Comment Process</FP> <FP SOURCE="FP-2">III. Summary of Public Comments and EPA's Responses</FP> <FP SOURCE="FP-2">IV. What action is EPA taking?</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> On August 23, 2021, EGLE submitted a revision to its SIP to address regional haze requirements for the second implementation period. On July 24, 2025, EGLE submitted a supplement (Supplement) to its original submission providing expanded source-specific analyses and emissions updates. EGLE made this SIP submission to satisfy the requirements of the CAA's regional haze program pursuant to CAA sections 169A and 169B and 40 CFR 51.308. EPA proposed to approve EGLE's submission into the SIP on June 18, 2025. A full background, the specifics of the Michigan regional haze plan, and EPA's evaluation of the plan are given in the proposed rule and will not be restated in this rule. See 90 FR 25975 (June 18, 2025). EGLE submitted the Supplement in draft for parallel processing on April 3, 2025. Detail on parallel processing is provided in the proposed rule. In this final action, EPA is affirming that it is now the Agency's policy that, where visibility conditions for a Class I Federal area impacted by a State are below the uniform rate of progress (URP) and the State has considered the four statutory factors, the State will have presumptively demonstrated reasonable progress for the second planning period for that area. EPA acknowledges that this final action reflects a change in policy as to how the URP should be used in the evaluation of regional haze second planning period SIPs but believes that this policy better aligns with the purpose of the statute and RHR: achieving “reasonable” progress towards natural visibility. As described in the approval of West Virginia's regional haze plan (90 FR 29737, July 7, 2025), EPA has discretion and authority to change its policy. In <E T="03">FCC</E> v. <E T="03">Fox Television Stations, Inc.,</E> the U.S. Supreme Court plainly stated that an agency is free to change a prior policy and “need not demonstrate . . . that the reasons for the new policy are better than the reasons for the old one; it suffices that the new policy is permissible under the statute, that there are good reasons for it, and that the agency believes it to be better.” 566 U.S. 502, 515 (2009) (referencing Motor <E T="03">Vehicle Mfrs. Ass'n of United States, Inc.</E> v. <E T="03">State Farm Mut. Auto. Ins. Co.,</E> 463 U.S. 29 (1983)). <E T="03">See also Perez</E> v. <E T="03">Mortgage Bankers Assn.,</E> 135 S. Ct. 1199 (2015). The Class I areas impacted by emissions from Michigan sources are all below the 2028 URP, and EGLE's SIP submission demonstrated that the State took into consideration the four reasonable progress factors listed in CAA 169A(g)(1)  <SU>1</SU> <FTREF/> with respect to an adequate number of emissions sources. Thus, EPA determines that EGLE's SIP revision is fully approvable. <FTNT> <SU>1</SU>   The four statutory factors required to be taken into consideration in determining reasonable progress are: the costs of compliance, the time necessary for compliance, and the energy and non-air quality environmental impacts of compliance, and the remaining useful life of any existing source subject to such requirements. CAA section 169(g)(1). </FTNT> In developing the regulations required by CAA section 169A(b), EPA established the concept of the URP for each Class I area. The URP is determined by drawing a straight line from the measured 2000 to 2004 baseline conditions (in deciviews) for the 20 percent most impaired days at each Class I area to the estimated natural conditions (in deciviews) for the 20 percent most impaired days in 2064. From this calculation, a URP value can be calculated for each year between 2004 and 2064. EPA developed the URP to address the diverse concerns of Eastern and Western States and account for the varying levels of visibility impairment in Class I areas around the country while ensuring an equitable approach nationwide. For each Class I area, States must calculate the URP for the end of each planning period ( <E T="03">e.g.,</E> in 2028 for the second planning period). <SU>2</SU> <FTREF/> 40 CFR 51.308(f)(1)(vi)(A). States may also adjust the URP to account for impacts from anthropogenic sources outside the United States and/or impacts from certain wildland prescribed fires. 40 CFR 51.308(f)(1)(vi)(B). Then, for each Class I area, States must compare the reasonable progress goal (RPG) for the 20 percent most impaired days to the URP for the end of the planning period. If the RPG is above the URP, then an additional “robust demonstration” requirement is triggered for each State that contributes to that Class I area. 40 CFR 51.308(f)(3)(ii)(B). <FTNT> <SU>2</SU>  We note that RPGs are a regulatory construct that we developed to address the statutory mandate in CAA section 169B(e)(1), which required our regulations to include “criteria for measuring `reasonable progress' toward the national goal.” Under 40 CFR 51.308(f)(3)(ii), RPGs measure the progress that is projected to be achieved by the control measures a State has determined are necessary to make reasonable progress. Consistent with the 1999 RHR, the RPGs are unenforceable, though they create a benchmark that allows for analytical comparisons to the URP and mid-implementation-period course corrections if necessary. 82 FR 3091-92 (January 10, 2017). </FTNT> In the 2017 RHR Revisions, EPA addressed the role of the URP as it relates to a State's development of its second planning period SIP. 82 FR 3078 (January 10, 2017). Specifically, in response to comments suggesting that the URP should be considered a “safe harbor” that relieve States of any obligation to consider the four statutory factors, EPA explained that the URP was not intended to be such a safe harbor. <E T="03">Id.</E> at 3099. “Some commenters stated a desire for corresponding rule text dealing with situations where RPGs are equal to (“on”) or better than (“below”) the URP or glidepath. Several commenters stated that the URP or glidepath should be a `safe harbor,' opining that States should be permitted to analyze whether projected visibility conditions for the end of the implementation period will be on or below the glidepath based on on-the-books or on-the-way control measures, and that in such cases a four-factor analysis should not be required.” <E T="03">Id.</E> Other comments indicated a similar approach, such as “a somewhat narrower entrance to a `safe harbor,' by suggesting that if current visibility conditions are already below the end-of-planning-period point on the URP line, a four-factor analysis should not be required.” <E T="03">Id.</E> EPA stated in its response that we did not agree with either of these recommenda ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 39k characters. 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