Air Plan Approval; Michigan; Detroit 2010 Sulfur Dioxide Redesignation and Maintenance Plan

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Parts 52 and 81</CFR> <DEPDOC>[EPA-R05-OAR-2025-0238; FRL-12841-01-R5]</DEPDOC> <SUBJECT>Air Plan Approval; Michigan; Detroit 2010 Sulfur Dioxide Redesignation and Maintenance Plan</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing to find that the Detroit, Michigan area is attaining the 2010 sulfur dioxide (SO <E T="52">2</E> ) National Ambient Air Quality Standard (NAAQS) and to act in accordance with a request from Michigan to redesignate the area to attainment for the 2010 SO <E T="52">2</E> NAAQS, because the request meets the statutory requirements for redesignation under the Clean Air Act (CAA). EPA is also proposing to approve Michigan's maintenance plan for the Detroit area. Michigan submitted the request for approval of the Detroit nonattainment area's redesignation and maintenance plan on May 5, 2025. EPA approved Michigan's attainment plan for the Detroit area on May 19, 2025. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Comments must be received on or before September 15, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R05-OAR-2025-0238 at <E T="03">https://www.regulations.gov,</E> or via email to <E T="03">arra.sarah@epa.gov.</E> For comments submitted at <E T="03">Regulations.gov,</E> follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from the docket. EPA may publish any comment received to its public docket. Do not submit to EPA's docket at <E T="03">https://www.regulations.gov</E> any information you consider to be Confidential Business Information (CBI), Proprietary Business Information (PBI), 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. EPA will generally not consider comments or comment contents located outside of the primary submission ( <E T="03">i.e.,</E> on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. For the full EPA public comment policy, information about CBI, PBI, or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">https://www.epa.gov/dockets/commenting-epa-dockets.</E> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Abigail Teener, Air and Radiation Division (AR-18J), Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, (312) 353-7314, <E T="03">teener.abigail@epa.gov.</E> The EPA Region 5 office is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding Federal holidays. </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">I. Background and Redesignation Requirements</HD> On June 22, 2010 (75 FR 35520), EPA published a new SO <E T="52">2</E> NAAQS of 75 parts per billion (ppb), which is met at an ambient air quality monitoring site when the 3-year average of the annual 99th percentile of daily maximum 1-hour average concentrations does not exceed 75 ppb, as determined in accordance with appendix T of 40 CFR part 50. Upon promulgation of a new or revised NAAQS, section 107(d)(1)(B) of the CAA requires EPA to designate as nonattainment any areas that are violating the NAAQS. On August 5, 2013 (78 FR 47191), EPA designated the Detroit area, a portion of Wayne County, Michigan, as nonattainment for the 2010 SO <E T="52">2</E> NAAQS based on ambient air quality data collected at the Detroit SW monitoring site (AQS ID 26-163-0015) from 2009 to 2011. The nonattainment area designation became effective on October 4, 2013. Section 191 of the CAA directs states to submit a State Implementation Plan (SIP) for an area designated as nonattainment for the 2010 SO <E T="52">2</E> NAAQS to EPA within 18 months of the effective date of the designation, <E T="03">i.e.,</E> by no later than April 4, 2015, in this case. The SIP must demonstrate attainment of the NAAQS as expeditiously as practicable, but no later than five years from the effective date of designation, which was October 4, 2018, for the Detroit nonattainment area. On March 18, 2016 (81 FR 14736), EPA published an action finding that Michigan had failed to submit the required SO <E T="52">2</E> nonattainment plan by the submittal deadline. This finding initiated deadlines under CAA section 179(a) for the potential imposition of 2-to-1 New Source Review (NSR) offset and Federal highway funding sanctions. Additionally, under CAA section 110(c), the finding triggered a requirement that EPA promulgate a Federal Implementation Plan (FIP) within two years of the finding unless, by that time, (a) the State had made the necessary complete submittal, and (b) EPA had approved the submittal as meeting applicable requirements. On May 31, 2016, Michigan submitted a Detroit SO <E T="52">2</E> attainment plan and on June 30, 2016, submitted associated final enforceable measures. Michigan's submission of a complete attainment plan terminated the deadlines for imposing sanctions, pursuant to 40 CFR 52.31(d)(5), but it did not terminate EPA's FIP obligation. On March 19, 2021 (86 FR 14827), EPA partially approved and partially disapproved Michigan's SO <E T="52">2</E> plan as submitted in 2016. EPA's March 19, 2021, action approved the enforceable control measures for two facilities, approved the base-year emissions inventory, and affirmed that the NSR requirements for the area had previously been met. In the same March 19, 2021, action, EPA disapproved the attainment demonstration, as well as the requirements for meeting reasonable further progress (RFP) toward attainment of the NAAQS, reasonably available control measures/reasonably available control technology (RACM/RACT), and contingency measures. Additionally, EPA disapproved the plan's control measures for two facilities as insufficient to demonstrate attainment. These disapprovals started a new sanctions clock under CAA section 179(a). On January 28, 2022 (87 FR 4501), EPA issued a finding of failure to attain for the Detroit SO <E T="52">2</E> nonattainment area, determining that the area failed to attain the 2010 SO <E T="52">2</E> NAAQS by the applicable attainment date of October 4, 2018, and established a requirement that Michigan submit a revised SIP by January 30, 2023, that would provide for expeditious attainment of the NAAQS within the time period specified in CAA sections 179(d)(3) and 172(a)(2). On October 12, 2022 (87 FR 61514), EPA promulgated a FIP for the Detroit SO <E T="52">2</E> nonattainment area, which satisfied EPA's duty to promulgate a FIP for the area under CAA section 110(c) that resulted from the March 18, 2016, finding of failure to submit. While EPA's FIP for the Detroit area met the requirements for SO <E T="52">2</E> nonattainment area plans, the FIP did not relieve Michigan of the previously discussed CAA requirement to submit a plan that provides for attainment of the 2010 SO <E T="52">2</E> NAAQS for the Detroit nonattainment area. On December 20, 2022, Michigan submitted a revised attainment plan for the Detroit SO <E T="52">2</E> nonattainment area mirroring EPA's FIP to remedy Michigan's 2016 plan deficiencies specified in EPA's March 19, 2021, rulemaking partially approving and partially disapproving Michigan's SIP. Michigan's revised plan, as submitted on December 20, 2022, depended, in part, upon permits that had not yet been issued but would include limits and associated requirements for the United States Steel Corporation (U.S. Steel), EES Coke Battery (EES Coke), and Dearborn Industrial Generation (DIG) facilities containing emission limits and associated requirements no less stringent than those set forth in EPA's FIP, codified at 40 CFR 52.1189. On February 21, 2023, Michigan submitted a clarification letter committing to submit the necessary permits by April 30, 2024. On March 23, 2023 (88 FR 17488), EPA proposed to conditionally approve Michigan's plan, conditioned upon the issuance of and submission for incorporation into the SIP the applicable permits for the U.S. Steel, EES Coke, and DIG facilities. Also, on March 23, 2023 (88 FR 17376), EPA issued an interim final determination to stay and defer sanctions in the Detroit SO <E T="52">2</E> nonattainment area based on EPA's proposed conditional approval. On December 14, 2023, Michigan submitted three applicable permits for the U.S. Steel, EES Coke, and DIG facilities. On April 2, 2024, the State submitted the final applicable permit for the DIG facility, along with a request that EPA approve its revised plan. On April 29, 2024, EPA issued a completeness letter, included in the docket for this action, determining that Michigan's submittal had satisfied the completeness criteria set forth at 40 CFR part 51, appendix V and met the requirement for a SIP submittal that provides for expeditious attainment set forth in EPA's January 28, 2022, finding of failure to attain. On May 19, 2025 (90 FR 21228), EPA approved Michigan's revised SIP submission, which the State submitted to EPA on December 20, 2022, and supplemented on February 21, 2023, December 14, 2023, and April 2, 2024, for attaining the 2010 SO <E T="52">2</E> NAAQS for the Detroit area and for meeting other nonattainment area planning requirements of CAA sections 110, 172, 179 and 192. EPA approved Michigan's demonstration that these requirements provide for attainment of th ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 49k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━