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 Environmental Protection Agency 40 CFR Part 52
[EPA-R05-OAR-2022-0976; FRL-10788-04-R5]
 AGENCY: Environmental Protection Agency (EPA)
 ACTION: Proposed rule.
 SUMMARY: The Environmental Protection Agency (EPA) is proposing to approve the State Implementation Plan (SIP) revision submitted by Michigan on December 20, 2022, and supplemented on February 21, 2023, December 14, 2023, and April 2, 2024, which amends a SIP submission previously submitted to EPA on May 31, 2016, and June 30, 2016, for attaining the 1-hour sulfur dioxide (SO2) primary national ambient air quality standard (NAAQS) for the Detroit SO2
                         nonattainment area. This action supplements a prior action which found that Michigan had satisfied emission inventory and new source review (NSR) requirements for this area, but had not met requirements under the Clean Air Act (CAA) for the elements proposed to be approved here.
 DATES: Comments must be received on or before November 4, 2024.
 ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-OAR-2022-0976 at 
                        *https://www.regulations.gov,*
                         or via email to 
                        *arra.sarah@epa.gov.*
                         For comments submitted at 
                        *Regulations.gov*, 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 
                        *https://www.regulations.gov*
                         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 (
                        *i.e.,*
                         on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the 
                        **FOR FURTHER INFORMATION CONTACT**
                         section. For the full EPA public comment policy, 
                        ( print page 80440)
                        information about CBI, PBI, or multimedia submissions, and general guidance on making effective comments, please visit 
                        *https://www.epa.gov/​dockets/​commenting-epa-dockets.*
 FOR FURTHER INFORMATION CONTACT: Abigail Teener, Air and Radiation Division (AR18J), Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, (312) 353-7314, 
                        *teener.abigail@epa.gov.*
                         The EPA Region 5 office is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding Federal holidays.


SUPPLEMENTARY INFORMATION: This supplementary information section is arranged as follows: I. Why was Michigan required to submit an SO2
                         plan for the Detroit area? II. Requirements for SO2
                         Nonattainment Area Plans III. Review of Michigan's Attainment Plan IV. Review of Other Plan Requirements A. RACM/RACT B. Reasonable Further Progress C. Contingency Measures V. What action is EPA taking? VI. Incorporation by Reference VII. Statutory and Executive Order Reviews I. Why was Michigan required to submit an SO
                    2
                     plan for the Detroit area? On June 22, 2010, EPA published a new 1-hour primary SO2
                     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. 
                    *See*75 FR 35520, codified at 40 CFR 50.17(a)-(b). On August 5, 2013, EPA designated 29 areas of the country as nonattainment for the 2010 SO2
                     NAAQS, including the Detroit area within the State of Michigan. 
                    *See*78 FR 47191, codified at 40 CFR part 81, subpart C. These area designations became effective on October 4, 2013. Section 191 of the CAA directs states to submit SIPs for areas designated as nonattainment for the 1-hour primary SO2
                     NAAQS to EPA within 18 months of the effective date of the designation, 
                    *i.e.,*
                     by no later than April 4, 2015, in this case. These SIPs were required to demonstrate that their respective areas would attain the NAAQS as expeditiously as practicable, but no later than five years from the effective date of designation, which was October 4, 2018. For a number of nonattainment areas, including the Detroit area, EPA published an action on March 18, 2016 (effective April 18, 2016), finding that Michigan and other pertinent states had failed to submit the required SO2
                     nonattainment area plans by the submittal deadline (81 FR 14736). Michigan submitted an attainment plan for the Detroit SO2
                     nonattainment area on May 31, 2016, and submitted associated enforceable emission limits and control measures on June 30, 2016. These measures included Michigan Administrative Code (MAC) 336.1430 (“Rule 430”), which imposed emission limits for U.S. Steel. Subsequently, U.S. Steel challenged the legality of Rule 430 under state law in the Michigan Court of Claims, which invalidated Rule 430 on October 4, 2017. 
                    *United States Steel Corp.*
                     v. 
                    *Dept. of Environmental Quality,*
                     No. 16-000202-MZ, 2017 WL 5974195 (Mich. Ct. Cl. Oct. 4, 2017). Because the State's submitted attainment demonstration relied on a limitation that had become unenforceable and, therefore, could not meet the requirements of CAA sections 110 and 172, EPA could not fully approve Michigan's 2016 plan. On March 19, 2021, EPA partially approved and partially disapproved Michigan's SO2
                     plan as submitted in 2016 (86 FR 14827) (effective April 19, 2021). EPA approved the base-year emissions inventory and affirmed that the nonattainment NSR requirements for the area had previously been met on December 16, 2013 (78 FR 76064). EPA also approved the enforceable control measures for two facilities as SIP strengthening. At that time, EPA disapproved the attainment demonstration, as well as Michigan's proposed requirements for meeting reasonable further progress (RFP) toward attainment of the NAAQS, Reasonably Available Control Measures (RACM)/Reasonably Available Control Technology (RACT), and contingency measures. Additionally, EPA disapproved the plan's control measures for two facilities as not demonstrating attainment. EPA's March 19, 2021, partial disapproval started a sanctions clock under CAA section 179. On January 28, 2022, EPA issued a finding of failure to attain (FFA) for the Detroit SO2
                     nonattainment area, determining that the area failed to attain the 1-hour primary SO2
                     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 provides for expeditious attainment of the NAAQS within the time period specified in CAA sections 179(d)(3) and 172(a)(2). 87 FR 4501, 4503, codified at 40 CFR 52.1170(e). Michigan subsequently submitted SIP revisions on December 20, 2022, February 21, 2023, December 14, 2023, and April 2, 2024. EPA is proposing here that the State's SIP submission meets the CAA requirements to provide for expeditious attainment of the NAAQS as required by EPA's January 28, 2022, FFA. On October 12, 2022, EPA promulgated a Federal Implementation Plan (FIP) for the Detroit SO2
                     nonattainment area (87 FR 61514), 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 SO2
                     nonattainment area plans, the FIP did not relieve Michigan of the previously discussed CAA requirements to submit a plan that provides for attainment of the 1-hour primary SO2
                     NAAQS for the Detroit nonattainment area. On December 20, 2022, Michigan submitted a revised attainment plan for the Detroit SO2
                     nonattainment area mirroring EPA's FIP in order 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 U.S. Steel, EES Coke, and Dearborn Industrial Generation (DIG) facilities that are no less stringent than those set forth in EPA's FIP, codified at 40 CFR 52.1189. On March 23, 2023, EPA proposed to conditionally approve Michigan's plan, conditional upon the issuance of and submission for incorporation into the SIP the applicable permits for the U.S. Steel, EES Coke, and DIG facilities (88 FR 17488). Also on March 23, 2023, EPA issued an interim final determination to stay and defer sanctions in the Detroit SO2
                     nonattainment area based on EPA's proposed conditional approval (88 FR 17376). However, the sanctions clock is permanently stopped only by meeting the conditions of EPA's regulations at 40 CFR 52.31(d), which EPA is proposing have been met here. On December 14, 2023, the State 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 
                    ( print page 80441)
                    provides for expeditious attainment set forth in EPA's January 28, 2022 FFA. The remainder of this action describes the requirements that SO2
                     nonattainment plans must meet in order to obtain EPA approval, provides a review of Michigan's revised plan with respect to these requirements, and describes EPA's proposed approval of the plan. II. Requirements for SO
                    2
                     Nonattainment Area Plans Nonattainment SIPs must meet the applicable requirements of the CAA, and specifically CAA sections 110, 172, 191 and 192. EPA's regulations governing nonattainment SIPs are set forth at 40 CFR part 51, with specific procedural requirements and control strategy requirements residing at subparts F and G, respectively. Soon after Congress enacted the 1990 Amendments to the CAA, EPA issued comprehensive guidance on SIPs, in a document entitled the “General Preamble for the Implementation of Title I of the CAA Amendments of 1990,” published at 57 FR 13498 (April 16, 1992) (General Preamble). Among other things, the General Preamble addressed SO2
                     SIPs and fundamental principles for SIP control strategies. 
                    *Id.,*
                     at 13545-49, 13567-68. On April 23, 2014, EPA issued recommended guidance for meeting the statutory requirements in SO2
                     SIPs, in a document entitled, “Guidance for 1-Hour SO2
                     Nonattainment Area SIP Submissions,” available at 
                    *https://www.epa.gov/​sites/​production/​files/​2016-06/​documents/​20140423guidance_​nonattainment_​sip.pdf.*
                     In this guidance EPA described the statutory requirements for a complete nonattainment area SIP, which includes: an accurate emissions inventory of current emissions for all sources of SO2
                     within the nonattainment area; an attainment demonstration; demonstration of RFP; implementation of RACM (including RACT); nonattainment area NSR; enforceable emissions limitations and control measures as necessary to attain the NAAQS; and adequate contingency measures for the affected area. EPA already concluded in its March 19, 2021, rulemaking that Michigan has met the emissions inventory and nonattainment area NSR requirements. In order for EPA to approve a SIP as meeting the requirements of CAA sections 110, 172 and 191-192 and EPA's regulations at 40 CFR part 51, the SIP for the affected area needs to demonstrate to EPA's satisfaction that each of the aforementioned requirements have been met. Under CAA sections 110(l) and 193, EPA may not approve a SIP that would interfere with or modify any applicable requirement in any area which is nonattainment for any air pollutant unless it ensures equivalent or greater emission reductions of such air pollutant. Such requirements include those concerning NAAQS attainment and RFP, or any other applicable requirement, or any requirement in effect (or required to be adopted by an order, settlement, agreement, or plan in effect before November 15, 1990). CAA section 172(c)(1) directs states with areas designated as nonattainment to demonstrate that the submitted plan provides for attainment of the NAAQS. 40 CFR part 51, subpart G, further delineates the control strategy requirements that SIPs must meet, and EPA has long required that all SIPs and control strategies reflect four fundamental principles of quantification, enforceability, replicability, and accountability. 
                    *See*
                     General Preamble at 13567-68. SO2
                     attainment plans must consist of two components: (1) emission limits and other control measures that ensure implementation of permanent, enforceable and necessary emission controls, and (2) a modeling analysis which meets the requirements of 40 CFR part 51, appendix W, which demonstrates that these emission limits and control measures provide for timely attainment of the 1-hour primary SO2
                     NAAQS as expeditiously as practicable, but by no later than the attainment date for the affected area. In all cases, the emission limits and control measures must be accompanied by appropriate methods and conditions to determine compliance with the respective emission limits and control measures and must be quantifiable (
                    *i.e.,*
                     a specific amount of emission reduction can be ascribed to the measures), fully enforceable (specifying clear, unambiguous and measurable requirements for which compliance can be practicably determined), replicable (the procedures for determining compliance are sufficiently specific and non-subjective so that two independent entities applying the procedures would obtain the same result), and accountable (source specific limits must be permanent and must reflect the assumptions used in the SIP demonstrations). Preferred air quality models for use in regulatory applications are described in appendix A of EPA's 
                    *Guideline on Air Quality Models (40 CFR part 51, appendix W).*
                     In 2005, EPA promulgated the AERMOD model as the Agency's preferred near-field dispersion modeling for a wide range of regulatory applications addressing stationary sources (for example in estimating SO2
                     concentrations) in all types of terrain based on extensive developmental and performance evaluation. Supplemental guidance on modeling for purposes of demonstrating attainment of the SO2
                     standard is provided in appendix A to the April 23, 2014, SO2
                     nonattainment area SIP guidance document referenced above. Appendix A provides extensive guidance on the modeling domain, the source inputs, assorted types of meteorological data, and background concentrations. Consistency with the recommendations in this guidance is generally necessary for the attainment demonstration to offer adequately reliable assurance that the plan provides for attainment. As stated previously, attainment demonstrations for the 2010 1-hour primary SO2
                     NAAQS must demonstrate future attainment and maintenance of the NAAQS in the entire area designated as nonattainment (
                    *i.e.,*
                     not just at the violating monitor). This is demonstrated by using air quality dispersion modeling (
                    *see*
                     appendix W to 40 CFR part 51) that shows that the mix of sources, enforceable control measures, and emission rates in an identified area will not lead to a violation of the SO2
                     NAAQS. For a short-term (
                    *i.e.,*
                     1-hour) standard, EPA believes that dispersion modeling, using allowable emissions and addressing stationary sources in the affected area (and in some cases those sources located outside the nonattainment area which may affect attainment in the area) is technically appropriate, efficient and effective in demonstrating attainment in nonattainment areas because it takes into consideration combinations of meteorological and emission source operating conditions that may contribute to peak ground-level concentrations of SO2. The meteorological data used in the analysis should generally be processed with the most recent version of the AERMET data preprocessor. Estimated concentrations should include ambient background concentrations, should follow the form of the standard, and should be calculated as described in section 2.6.1.2 of the August 23, 2010, clarification memo on “Applicability of Appendix W Modeling Guidance for the 1-hr SO2
                     National Ambient Air Quality Standard” (U.S. EPA, 2010). For a more in-depth discussion on the requirements of SO2
                     nonattainment plans, including the use of longer-term average limits, 
                    *see*
                     EPA's proposed FIP (87 FR 33095, June 1, 2022).
                    ( print page 80442) III. Review of Michigan's Attainment Plan Michigan's plan for the Detroit nonattainment area mirrors EPA's final promulgated FIP for the area. Therefore, Michigan's plan relies on the modeling analysis EPA used to support its FIP, which is attached as appendix B of Michigan's December 20, 2022, submittal, to demonstrate attainment of the 2010 SO2
                     NAAQS in the Detroit area. A more in-depth discussion of the modeling analysis may be found in EPA's proposed FIP (87 FR 33095) and the associated technical support document, which is included in the docket for this action as appendix B of Michigan's December 20, 2022, submittal. An important aspect of an attainment plan is that the emission limits that provide for attainment be quantifiable, fully enforceable, replicable, and accountable. 
                    *See*
                     General Preamble at 13567-68. Michigan's attainment plan includes the same limits for the U.S. Steel, EES Coke, Cleveland-Cliffs Steel Corporation, DIG, Carmeuse Lime, and DTE Trenton Channel facilities that are included in EPA's FIP, and which are all shown below in Table 1. The plan also includes the same requirement that a 170-foot stack be constructed at U.S. Steel Boilerhouse 2 by November 14, 2024, as set forth in EPA's FIP. The FIP made all of these limits and requirements that had not already been incorporated into Michigan's SIP federally enforceable via inclusion in the FIP regulatory language, codified at 40 CFR 52.1189. As Michigan's plan cannot simply rely on the limits and requirements set forth in the FIP regulatory language but must adopt them as state requirements in order for the revised SIP to be approved, the enforcement mechanisms of all the limits relied upon by Michigan's plan are described in the remainder of this section. In preparing its 2016 plan, Michigan adopted Permit to Install 193-14A, governing the Carmeuse Lime SO2
                     emissions, and Permit to Install 125-11C, governing the DTE Trenton Channel SO2
                     emissions. These construction permit revisions were adopted by Michigan following established, appropriate public review procedures. The permit compliance dates were October 1, 2018, for Carmeuse Lime and January 1, 2017, for DTE Trenton Channel. Both of these permits were incorporated into Michigan's SIP as part of EPA's March 19, 2021, action partially approving and partially disapproving Michigan's SO2
                     plan (86 FR 14827). The Carmeuse Lime and DTE Trenton Channel permits were incorporated into Michigan's SIP as part of EPA's March 19, 2021, action. DTE Trenton Channel has since permanently shut down as of June 19, 2022, under court order, which is included in the docket for this action. The DTE Trenton Channel permitted limit was included in the FIP analysis as a precautionary measure, so it is therefore included in Michigan's revised plan. However, any restart would require a revision to the source's Title V permit, subject to EPA review and possible objection if a permit revision would not ensure compliance with all applicable CAA requirements. Emission limits and associated requirements for U.S. Steel, EES Coke, Cleveland-Cliffs Steel Corporation, and DIG, including the construction of a new 170-foot stack for U.S. Steel Boilerhouse 2 by November 14, 2024, are contained in permits specified in Table 1 below. These limits and associated monitoring requirements were also included in EPA's FIP, codified at 40 CFR 52.1189. The permit revisions were adopted by Michigan following established, appropriate public review procedures. EPA finds that these permit revisions provide for permanent enforceability and is proposing to incorporate these permits into Michigan's SIP in this action. Table 1—Emission Limits Included in Michigan's Detroit SO
                        2
                         Nonattainment Area Plan
Unit
SO
                            2
                             emission
                             limit 
                             (lb/hr)
Permit No. and date
SIP status**U.S. Steel—Zug Island**Boilerhouse 1 (all stacks combined)
                             A1 Blast Furnace
55.00
                             0.00
Permit to Install 110-23, effective September 26, 2023
EPA is proposing to incorporate these permits into Michigan's SIP.B2 Blast Furnace
40.18D4 Blast Furnace
40.18A/B Blas Furnace Flares
60.19D Furnace Flare
60.19Boilerhouse 2
* 750.00/81.00
Permit to Install 108-23, effective November 14, 2024**U.S. Steel—Ecorse**Hot Strip Mill—Slab Reheat Furnace 1
                             Hot Strip Mill—Slab Reheat Furnace 2
0.31
                             0.31
Permit to Install 110-23, effective September 26, 2023
EPA is proposing to incorporate this permit into Michigan's SIP.Hot Strip Mill—Slab Reheat Furnace 3
0.31Hot Strip Mill—Slab Reheat Furnace 4
0.31Hot Strip Mill—Slab Reheat Furnace 5
0.31No. 2 Baghouse
3.30Main Plant Boiler No. 8
0.07Main Plant Boiler No. 9
0.07**EES Coke**Combustion Stack
544.6
Permit to Install 51-08C, effective November 21, 2014
EPA is proposing to incorporate this permit into Michigan's SIP.( print page 80443)**DTE Trenton Channel**
                             **Trenton Channel Unit 9
5,907
Permit to Install 125-11C, effective January 1, 2017
Incorporated into Michigan's SIP as part of March 19, 2021, action (86 FR 14827). However, the source has since shut down, and any restart would require a revision to the source's Title V permit, subject to EPA review and possible objection if a permit revision would not ensure compliance with all applicable CAA requirements.**Carmeuse Lime**Carmeuse Lime Stack
470
Permit to Install 193-14A, effective October 1, 2018
Incorporated into Michigan's SIP as part of March 19, 2021, action (86 FR 14827).**Cleveland-Cliffs Steel Corporation**
                             **Furnace B Baghouse Stack
                             Furnace B Stove Stack
71.9
                             38.75
Permit MI-ROP-A8640-2016a, modified January 19, 2017
EPA is proposing to incorporate this permit into Michigan's SIP.Furnace B Baghouse and Stove Stacks (combined)
77.8Furnace C Baghouse Stack
179.65Furnace C Stove Stack
193.6Furnace C Baghouse and Stove Stacks (combined)
271.4**DIG**
                             **Boilers 1, 2, and 3 (combined)
420
Permit 253-02A, effective September 25, 2003
EPA is proposing to incorporate the sections of this permit containing the 420 lb/hr limit and associated requirements (cover page, section 5.1d, and sections 5.2-5.10) into Michigan's SIP.Boilers 1, 2, and 3 and Flares 1 and 2 (combined)
840
Permit to Install 109-23, effective September 26, 2023
EPA is proposing to incorporate this permit into Michigan's SIP.* U.S. Steel—Zug Island Boilerhouse 2 shall emit less than 750.00 lbs/hr unless Boilerhouse 1, A1 Blast Furnace, B2 Blast Furnace, D4 Blast Furnace, A/B Blast Furnace Flares, or D Furnace Flare is operating, in which case it shall emit less than 81.00 lbs/hr. In addition to the limit, this permit requires a new 170-foot stack to be constructed for Boilerhouse 2 by November 14, 2024.** The limit for Trenton Channel is expressed as a 30-day average limit, and the limits for Cleveland-Cliffs Steel Corporation and DIG are expressed as daily average limits. EPA's FIP proposal addresses the use of these longer-term average limits, both with respect to the general suitability of using such limits for demonstrating attainment and with respect to whether the particular limits included in the plan have been suitably demonstrated to provide for attainment.
 Because Michigan's plan relies on the same modeling analysis that supports EPA's FIP and contains emission limits and associated requirements that are equally as stringent as EPA's FIP, EPA is proposing that Michigan's plan provides for attainment of the 1-hour primary SO2
                     NAAQS. IV. Review of Other Plan Requirements A. RACM/RACT CAA section 172(c)(1) states that nonattainment plans shall provide for the implementation of all RACM as expeditiously as practicable (including such reductions in emissions from existing sources in the area as may be obtained through the adoption, at a minimum, of RACT) and shall provide for attainment of the NAAQS by the applicable attainment date. For most criteria pollutants, RACT is control technology as needed to meet the NAAQS that is reasonably available considering technological and economic feasibility. However, the definition of RACT for SO2
                     is, simply, that control technology which is necessary to achieve the NAAQS (
                    *see*40 CFR 51.100(o)). CAA section 172(c)(6) requires plans to include enforceable emissions limitations, and such other control measures as may be necessary or appropriate to provide for attainment of the NAAQS by the applicable attainment date. In its March 19, 2021, rulemaking, EPA disapproved Michigan's 2016 attainment plan because it relied on Rule 430, which was invalidated in state court and so was no longer an available enforcement mechanism. Therefore, the plan could not be considered to provide an appropriate attainment demonstration, and it did not demonstrate RACM/RACT or meet the requirement for necessary enforceable emissions limitations or control measures. EPA's FIP for attaining the 1-hour primary SO2
                     NAAQS in the Detroit area was based on a variety of measures, including permits for Carmeuse Lime (effective date of October 1, 2018) and DTE Trenton Channel (effective date of January 1, 2017) that have been incorporated into Michigan's SIP, as well as the FIP regulatory language, codified at 40 CFR 52.1189, regarding U.S. Steel, EES Coke, Cleveland-Cliffs Steel Corporation, and DIG emissions. The FIP requires compliance by November 14, 2024, for U.S. Steel Boilerhouse 2 and November 14, 2022, for all other units. The compliance schedule for U.S. Steel Boilerhouse 2 includes time for the State of Michigan to issue the permit (completed on September 26, 2023), the owner or operator to send out requests for proposal and award a construction contract and procure materials, and for completion of construction. Since Michigan's plan follows the same compliance schedule by requiring compliance on the same dates as the FIP, EPA proposes to determine that these measures suffice to provide for attainment and proposes to conclude that Michigan's plan satisfies the requirement in sections 172(c)(1) and (6) to adopt and submit all RACM/RACT and enforceable emissions limitations or control measures as needed to attain the standards as expeditiously as practicable.
                    ( print page 80444) B. Reasonable Further Progress (RFP) Section 171(1) of the CAA defines RFP as such annual incremental reductions in emissions of the relevant air pollutant as are required by part D or may reasonably be required by EPA for the purpose of ensuring attainment of the applicable NAAQS by the applicable attainment date. This definition is most appropriate for pollutants that are emitted by numerous and diverse sources, where the relationship between any individual source and the overall air quality is not explicitly quantified, and where the emission reductions necessary to attain the NAAQS are inventory-wide. (
                    *See*
                     EPA's April 2014 SO2
                     nonattainment planning guidance, page 40.) For SO2,
                     there is usually a single “step” between pre-control nonattainment and post-control attainment. Therefore, for SO2,
                     with its discernible relationship between emissions and air quality, and significant and immediate air quality improvements, RFP is best construed as adherence to an ambitious compliance schedule. 
                    *See*
                     General Preamble at 74 FR 13547 (April 16, 1992). In its March 19, 2021, rulemaking, EPA concluded that Michigan had not satisfied the requirement in section 172(c)(2) to provide for RFP toward attainment. Michigan's 2016 attainment plan did not demonstrate that the implementation of the control measures required under the plan were sufficient to provide for attainment of the NAAQS in the Detroit SO2
                     nonattainment area, as some control measures were not enforceable due to the invalidation of Rule 430. Therefore, a compliance schedule to implement those controls was not sufficient to provide for RFP. EPA's FIP requires compliance by November 14, 2024, for U.S. Steel Boilerhouse 2 and November 14, 2022, for all other units. As described in section IV.A above, the 2-year compliance schedule for U.S. Steel Boilerhouse 2 includes time for the State of Michigan to issue the permit (completed on September 26, 2023), the owner or operator to send out requests for proposal and award a construction contract and procure materials, and for completion of construction. For DTE Trenton Channel and Carmeuse lime, compliance was required by January 1, 2017, and October 1, 2018, respectively. EPA concluded in the FIP that this is an ambitious compliance schedule, as that term is used in the April 2014 guidance for SO2
                     nonattainment plans. As Michigan's plan follows the same compliance schedule as the FIP, EPA concludes that this plan therefore provides for RFP in accordance with the approach to RFP described in EPA's 2014 guidance. C. Contingency Measures EPA guidance describes special features of SO2
                     planning that influence the suitability of alternative means of addressing the requirement in section 172(c)(9) for contingency measures for SO2, such that in particular an appropriate means of satisfying this requirement is for the air agency to have a comprehensive enforcement program that identifies sources of violations of the SO2
                     NAAQS and to undertake an aggressive follow-up for compliance and enforcement. 
                    *See*
                     EPA's April 2014 SO2
                     nonattainment planning guidance, page 41. Michigan has such an enforcement program, pursuant to section 5526 of part 55, Air Pollution Control, of the Natural Resources and Environmental Protection Act, 1994 PA 451, as amended, Michigan Compiled Laws 324.5526. Michigan enforcement and compliance authority is furthered by the State's title V program, which includes a compliance monitoring program, periodic inspections, review of company monitoring records, reporting, and issuance of violation notices for all violations shown from inspections or data. In addition, Michigan stated in its December 2022 submittal that it responds promptly to citizen complaints, reports all high priority violations to EPA, and puts all inspection reports and violation notices on Michigan's website. Therefore, EPA proposes that Michigan's plan satisfies the contingency measure requirement in accordance with the approach to contingency measures described in EPA's 2014 guidance. V. What action is EPA taking? EPA is proposing to approve 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 1-hour SO2
                     NAAQS for the Detroit area and for meeting other nonattainment area planning requirements of CAA sections 110, 172, 179 and 192. This SO2
                     attainment plan includes Michigan's attainment demonstration for the Detroit area. The plan also addresses requirements for RFP, RACT/RACM, enforceable emission limitations and control measures, and contingency measures. EPA previously concluded that Michigan has addressed the requirements for emissions inventories for the Detroit area and nonattainment area NSR. EPA has determined that Michigan's Detroit SO2
                     attainment plan meets applicable requirements of sections 110, 172, 179, and 192 of the CAA. Michigan's Detroit SO2
                     attainment plan is based on the Carmeuse Lime emission limits specified in Permit to Install 193-14A, the DTE Trenton Channel emission limits specified in Permit to Install 125-11C, the U.S. Steel limits specified in Permit to Install 110-23 and Permit to Install 108-23, the EES Coke emission limits specified in Permit to Install 51-08C, the Cleveland-Cliffs Steel Corporation emission limits specified in Permit MI-ROP-A8640-2016a, and the DIG emission limits specified in Permit 253-02A and Permit to Install 109-23. The Carmeuse Lime and DTE Trenton Channel permits have already been incorporated into Michigan's SIP, so EPA is not proposing to re-incorporate them into 40 CFR part 52 here. EPA is proposing to incorporate Permit to Install 110-23 and Permit to Install 108-23, governing U.S. Steel SO2
                     emissions; Permit to Install 51-08C, governing EES Coke SO2
                     emissions; Permit MI-ROP-A8640-2016a, governing Cleveland-Cliffs Steel Corporation SO2
                     emissions; and Permit to Install 109-23 and the cover sheet, section 5.1d (SO2
                     emission limit), and sections 5.2-5.10 (Special Conditions) of Permit 253-02A, governing DIG SO2
                     emissions into Michigan's SIP in this action. EPA is taking public comments for thirty days following the publication of this proposed action in the 
                    **Federal Register**
                    . EPA will take all comments into consideration in the final action. VI. Incorporation by Reference In this rule, EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, EPA is proposing to incorporate by reference Michigan Permit to Install 110-23, effective September 26, 2023; Permit to Install 108-23, effective November 14, 2024; Permit to Install 51-08C, effective November 21, 2014; Permit MI-ROP-A8640-2016a, modified January 19, 2017; Permit to Install 109-23, effective September 26, 2023; and the cover sheet, section 5.1d (SO2
                     emission limit), and sections 5.2-5.10 (Special Conditions) of Permit 253-02A, discussed in section III of this preamble. EPA has made, and will continue to make, these documents generally available through 
                    *www.regulations.gov*
                     and at the EPA Region 5 Office (please contact the person identified in the 
                    **FOR 
                        ( print page 80445)
                        FURTHER INFORMATION CONTACT**
                     section of this preamble for more information). VII. Statutory and Executive Order Reviews Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves 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 Orders 12866 (58 FR 51735, October 4, 1993), and 14094 (88 FR 21879, April 11, 2023);
                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 inExecutive Order 13132 (64 FR 43255, August 10, 1999);
                Is not subject toExecutive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;
                Is not a significant regulatory action subject toExecutive 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 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). Executive Order 12898 (Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations, 59 FR 7629, February 16, 1994) directs Federal agencies to identify and address “disproportionately high and adverse human health or environmental effects” of their actions on communities with environmental justice (EJ) concerns to the greatest extent practicable and permitted by law. EPA defines EJ as “the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.” EPA further defines the term fair treatment to mean that “no group of people should bear a disproportionate burden of environmental harms and risks, including those resulting from the negative environmental consequences of industrial, governmental, and commercial operations or programs and policies.” Michigan did not evaluate EJ considerations as part of its SIP submittal; the CAA and applicable implementing regulations neither prohibit nor require such an evaluation. EPA did not perform an EJ analysis and did not consider EJ in this action. Due to the nature of the action being taken here, this action is expected to have a neutral to positive impact on the air quality of the affected area. Consideration of EJ is not required as part of this action, and there is no information in the record inconsistent with the stated goal of E.O. 12898 of achieving EJ for communities with EJ concerns. List of Subjects in 40 CFR Part 52 Environmental protection
Air pollution control
Incorporation by reference
Intergovernmental relations
Reporting and recordkeeping requirements
Sulfur oxides
 Dated: September 18, 2024. Debra Shore, Regional Administrator, Region 5.


[FR Doc. 2024-21896 Filed 10-2-24; 8:45 am] BILLING CODE 6560-50-P