Air Plan Approval; Mississippi; PSD and Air Quality Modeling Infrastructure Requirements for the 2015 8-Hour Ozone National Ambient Air Quality Standards

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R04-OAR-2024-0186; FRL-12250-01-R4]</DEPDOC> <SUBJECT>Air Plan Approval; Mississippi; PSD and Air Quality Modeling Infrastructure Requirements for the 2015 8-Hour Ozone National Ambient Air Quality Standards</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 approve a State Implementation Plan (SIP) submission provided by the State of Mississippi, through the Mississippi Department of Environmental Quality (MDEQ), via a letter dated February 28, 2024. Specifically, EPA is proposing to approve updates to the incorporation by reference of Federal prevention of significant deterioration (PSD) rules in the Mississippi SIP. EPA is also proposing to convert the previous conditional approval of Mississippi's infrastructure SIP PSD and air quality modeling provisions for the 2015 Ozone National Ambient Air Quality Standards (NAAQS) to a full approval. EPA is also proposing changes to public notice provisions for PSD permitting to provide for electronic notice (e-notice) and to remove the mandatory requirement to provide public notice in a newspaper, and other minor changes to the PSD rules. EPA is proposing to approve these changes pursuant to the Clean Air Act (CAA or Act). </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Comments must be received on or before October 16, 2024. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R04-OAR-2024-0186 at <E T="03">www.regulations.gov.</E> Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from <E T="03">Regulations.gov</E> . 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. 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, the full EPA public comment policy, information about CBI 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> Josue Ortiz Borrero, Air Regulatory Management Section, Air Planning and Implementation Branch, Air and Radiation Division, U.S. Environmental Protection Agency, Region 4, 61 Forsyth Street SW, Atlanta, Georgia 30303-8960. The telephone number is (404) 562-8085. Mr. Ortiz Borrero can also be reached via electronic mail at <E T="03">ortizborrero.josue@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">I. Overview</HD> Mississippi's February 28, 2024, SIP submission seeks to revise the State's new source review (NSR) permitting regulations at 11 Mississippi Administrative Code (MAC), Part 2, Chapter 2, <E T="03">Permit Regulations for the Construction and/or Operation of Air Emissions Equipment</E> (Chapter 2) and PSD permitting regulations at 11 MAC, Part 2, Chapter 5, <E T="03">Regulations for the Prevention of Significant Deterioration of Air Quality</E> (Chapter 5) to adopt relevant Federal permitting regulations into the SIP. The PSD permitting changes at Chapter 5, amend MDEQ's incorporate by reference (IBR) date of the Federal PSD regulations at 40 CFR 51.166(f) and 40 CFR 52.21 to December 27, 2023. Mississippi's December 27, 2023, IBR date adopts into the SIP at Chapter 5, changes to 40 CFR 52.21 that EPA promulgated in several rulemakings since the Mississippi's last IBR update of February 17, 2016. The changes at Chapter 2 amend NSR general permitting requirements. EPA is also proposing to convert EPA's March 1, 2023, conditional approval of PSD and air quality modeling provisions at section 110(a)(2)(C), (D)(i)(II) (prong 3), (J), and (K), for Mississippi's infrastructure SIP for the 2015 ozone NAAQS to a full approval based on the revisions to Chapter 2 and Chapter 5. Lastly, the February 28, 2024, SIP submission proposes to revise the SIP-approved PSD regulations at Chapter 5 to adopt public participation revisions consistent with EPA's October 5, 2016, rule “Revisions to Public Notice Provisions in Clean Air Act Permitting Programs” Final Rule. <SU>1</SU> <FTREF/> <FTNT> <SU>1</SU>   <E T="03">See</E> 81 FR 71613. The February 28, 2024, SIP submission also updates 11 MAC, Part 2, Chapter 2 to address NSR requirements that will be addressed in a separate rulemaking. </FTNT> EPA's proposed rule briefly summarizes the framework of the PSD permitting program, how the program is implemented in Mississippi, and what Federal changes MDEQ is requesting EPA to IBR into its SIP. EPA is proposing to approve Mississippi's February 28, 2024, PSD revisions to Chapters 2 and 5 because they are consistent with EPA's Federal PSD permitting regulations and the CAA. EPA summarizes the PSD rule revisions in sections II.B and II.C of this document. Please refer to the referenced <E T="04">Federal Register</E> citations for additional detailed background on the Federal PSD regulations at 40 CFR 52.21. <HD SOURCE="HD1">II. Background</HD> <HD SOURCE="HD2">A. Mississippi's 2015 Ozone NAAQS Infrastructure SIP Submissions</HD> On October 1, 2015, EPA promulgated a revised primary and secondary NAAQS for ozone, revising the 8-hour ozone standards from 0.075 parts per million (ppm) to a new more protective level of 0.070 ppm. <E T="03">See</E> 80 FR 65292 (October 26, 2015). Pursuant to section 110(a)(1) of the CAA, States are required to submit SIP revisions meeting the applicable requirements of section 110(a)(2) within three years after promulgation of a new or revised NAAQS or within such shorter period as EPA may prescribe. Section 110(a)(2) requires States to address basic SIP elements such as requirements for monitoring, basic program requirements, and legal authority that are designed to assure attainment and maintenance of the NAAQS. This particular type of SIP is commonly referred to as an “infrastructure SIP” or “iSIP.” States were required to submit such SIP revisions for the 2015 8-hour ozone NAAQS to EPA no later than October 1, 2018. <SU>2</SU> <FTREF/> <FTNT> <SU>2</SU>  In infrastructure SIP submissions, States generally certify evidence of compliance with sections 110(a)(1) and (2) of the CAA through a combination of State regulations and statutes, some of which have been incorporated into the SIP. In addition, certain federally approved, non-SIP regulations may also be appropriate for demonstrating compliance with sections 110(a)(1) and (2). </FTNT> Mississippi submitted two SIP submissions on September 6, 2019, and January 25, 2021, to address their 110(a)(1) and (2) infrastructure obligations for the 2015 ozone standard. <SU>3</SU> <FTREF/> Through previous rulemakings, EPA approved most of the iSIP elements for the 2015 ozone NAAQS. <SU>4</SU> <FTREF/> <FTNT> <SU>3</SU>  Mississippi submitted their interstate transport SIP on September 6, 2019, to address the State's section 110(a)(2)(D)(i)(I) prongs 1 and 2 interstate transport obligations respecting contribution to nonattainment or interference with maintenance, respectively, in other States. EPA took final action on this submission on February 13, 2023, (88 FR 9336). On January 25, 2021, Mississippi submitted a second SIP revision to EPA to address all required infrastructure elements except for the interstate transport provisions of section 110(a)(2)(D)(i)(I) prongs 1 and 2. </FTNT> <FTNT> <SU>4</SU>   <E T="03">See</E> 87 FR 57832 (September 22, 2022), and 88 FR 9336 (February 13, 2023). </FTNT> On December 23, 2022, EPA proposed to conditionally approve  <SU>5</SU> <FTREF/> changes to portions of Mississippi's 2015 8-hour ozone NAAQS iSIP contained in MDEQ's original January 25, 2021, infrastructure submittal as supplemented on November 18, 2022. <E T="51">6 7</E> <FTREF/> Specifically, EPA proposed conditional approval of the PSD elements of CAA section 110(a)(2)(C), (D)(i)(II) (prong 3) and (J), and the modeling requirements of section 110(a)(2)(K) because Mississippi's SIP-approved PSD regulations did not, at the time, reference the most updated version of EPA's <E T="03">Guideline of Air Quality Models,</E> codified at 40 CFR part 51, Appendix W. On March 1, 2023, EPA finalized the conditional approval for the PSD infrastructure elements ( <E T="03">i.e.,</E> section 110(a)(2)(C), (D)(i)(II) (prong 3) and (J)), and the air quality modeling element of section 110(a)(2)(K), portion of the January 25, 2021, infrastructure SIP submission, as supplemented on November 18, 2022. <SU>8</SU> <FTREF/> <FTNT> <SU>5</SU>  Under CAA section 110(k)(4), EPA may conditionally approve a SIP revision based on a commitment from a State to adopt specific enforceable measures by a date certain, but not later than one year from the date of approval. If the State fails to meet the commitment within one year of the final conditional approval, the conditional approval will be treated as a disapproval and EPA will issue a finding of disapproval. </FTNT> <FTNT> <SU>6</SU>  Air Plan Approval; Mississippi; PSD and Air Quality Modeling Infrastructure Requirements for the 2015 8-Hour Ozone National Ambient Air Quality Standards, 87 FR 78896 (December 23, 2022 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 61k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━