[Federal Register Volume 89, Number 192 (Thursday, October 3, 2024)]
[Proposed Rules]
[Pages 80439-80445]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-21896]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R05-OAR-2022-0976; FRL-10788-04-R5]


Air Plan Approval; Michigan; Attainment Plan for the Detroit 2010 
Sulfur Dioxide Nonattainment Area

AGENCY: Environmental Protection Agency (EPA)

ACTION: Proposed rule.

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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 (SO<INF>2</INF>) primary national 
ambient air quality standard (NAAQS) for the Detroit SO<INF>2</INF> 
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 
<a href="/cdn-cgi/l/email-protection#adccdfdfcc83deccdfccc5edc8ddcc83cac2db"><span class="__cf_email__" data-cfemail="6e0f1c1c0f401d0f1c0f062e0b1e0f40090118">[email protected]</span></a>. 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,

[[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, 
<a href="/cdn-cgi/l/email-protection#cdb9a8a8a3a8bfe3acafa4aaaca4a18da8bdace3aaa2bb"><span class="__cf_email__" data-cfemail="1e6a7b7b707b6c307f7c77797f77725e7b6e7f30797168">[email protected]</span></a>. 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 SO<INF>2</INF> plan for 
the Detroit area?
II. Requirements for SO<INF>2</INF> 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 SO2 plan for the Detroit 
area?

    On June 22, 2010, EPA published a new 1-hour primary SO<INF>2</INF> 
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 SO<INF>2</INF> 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 SO<INF>2</INF> 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 SO<INF>2</INF> nonattainment area plans by the submittal 
deadline (81 FR 14736). Michigan submitted an attainment plan for the 
Detroit SO<INF>2</INF> 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 SO<INF>2</INF> 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 SO<INF>2</INF> nonattainment area, determining 
that the area failed to attain the 1-hour primary SO<INF>2</INF> 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 SO<INF>2</INF> 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 SO<INF>2</INF> 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 
SO<INF>2</INF> NAAQS for the Detroit nonattainment area. On December 
20, 2022, Michigan submitted a revised attainment plan for the Detroit 
SO<INF>2</INF> 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 SO<INF>2</INF> 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

[[Page 80441]]

provides for expeditious attainment set forth in EPA's January 28, 2022 
FFA.
    The remainder of this action describes the requirements that 
SO<INF>2</INF> 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 SO2 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 SO<INF>2</INF> 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 SO<INF>2</INF> SIPs, in a 
document entitled, ``Guidance for 1-Hour SO<INF>2</INF> 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 SO<INF>2</INF> 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. SO<INF>2</INF> 
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 SO<INF>2</INF> 
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 SO<INF>2</INF> concentrations) in all types of terrain 
based on extensive developmental and performance evaluation. 
Supplemental guidance on modeling for purposes of demonstrating 
attainment of the SO<INF>2</INF> standard is provided in appendix A to 
the April 23, 2014, SO<INF>2</INF> 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 SO<INF>2</INF> 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 SO<INF>2</INF> 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 SO<INF>2.</INF>
    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 SO<INF>2</INF> National Ambient Air Quality Standard'' 
(U.S. EPA, 2010).
    For a more in-depth discussion on the requirements of 
SO<INF>2</INF> nonattainment plans, including the use of longer-term 
average limits, see EPA's proposed FIP (87 FR 33095, June 1, 2022).

[[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 SO<INF>2</INF> 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 SO<INF>2</INF> emissions, and Permit 
to Install 125-11C, governing the DTE Trenton Channel SO<INF>2</INF> 
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 SO<INF>2</INF> 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 SO2 Nonattainment Area Plan
----------------------------------------------------------------------------------------------------------------
                                           SO2 emission
                  Unit                     limit (lb/hr)       Permit No. and date             SIP status
----------------------------------------------------------------------------------------------------------------
                                             U.S. Steel--Zug Island
----------------------------------------------------------------------------------------------------------------
Boilerhouse 1 (all stacks combined)....             55.00  Permit to Install 110-23,   EPA is proposing to
A1 Blast Furnace.......................              0.00   effective September 26,     incorporate these
                                                            2023.                       permits into Michigan's
                                                                                        SIP.
B2 Blast Furnace.......................             40.18
D4 Blast Furnace.......................             40.18
A/B Blas Furnace Flares................             60.19
D Furnace Flare........................             60.19
Boilerhouse 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..              0.31  Permit to Install 110-23,   EPA is proposing to
Hot Strip Mill--Slab Reheat Furnace 2..              0.31   effective September 26,     incorporate this permit
                                                            2023.                       into Michigan's SIP.
Hot Strip Mill--Slab Reheat Furnace 3..              0.31
Hot Strip Mill--Slab Reheat Furnace 4..              0.31
Hot Strip Mill--Slab Reheat Furnace 5..              0.31
No. 2 Baghouse.........................              3.30
Main Plant Boiler No. 8................              0.07
Main Plant Boiler No. 9................              0.07
----------------------------------------------------------------------------------------------------------------
                                                    EES Coke
----------------------------------------------------------------------------------------------------------------
Combustion Stack.......................             544.6  Permit to Install 51-08C,   EPA is proposing to
                                                            effective November 21,      incorporate this permit
                                                            2014.                       into Michigan's SIP.
----------------------------------------------------------------------------------------------------------------

[[Page 80443]]

 
                                             DTE Trenton Channel **
----------------------------------------------------------------------------------------------------------------
Trenton Channel Unit 9.................             5,907  Permit to Install 125-11C,  Incorporated into
                                                            effective January 1, 2017.  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,  Incorporated into
                                                            effective October 1, 2018.  Michigan's SIP as part
                                                                                        of March 19, 2021,
                                                                                        action (86 FR 14827).
----------------------------------------------------------------------------------------------------------------
                                      Cleveland-Cliffs Steel Corporation **
----------------------------------------------------------------------------------------------------------------
Furnace B Baghouse Stack...............              71.9  Permit MI-ROP-A8640-2016a,  EPA is proposing to
Furnace B Stove Stack..................             38.75   modified January 19, 2017.  incorporate this permit
                                                                                        into Michigan's SIP.
Furnace B Baghouse and Stove Stacks                  77.8
 (combined).
Furnace C Baghouse Stack...............            179.65
Furnace C Stove Stack..................             193.6
Furnace C Baghouse and Stove Stacks                 271.4
 (combined).
----------------------------------------------------------------------------------------------------------------
                                                     DIG **
----------------------------------------------------------------------------------------------------------------
Boilers 1, 2, and 3 (combined).........               420  Permit 253-02A, effective   EPA is proposing to
                                                            September 25, 2003.         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                840  Permit to Install 109-23,   EPA is proposing to
 (combined).                                                effective September 26,     incorporate this permit
                                                            2023.                       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 SO<INF>2</INF> 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 SO<INF>2</INF> 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 SO<INF>2</INF> 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.

[[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 
SO<INF>2</INF> nonattainment planning guidance, page 40.) For 
SO<INF>2,</INF> there is usually a single ``step'' between pre-control 
nonattainment and post-control attainment. Therefore, for 
SO<INF>2,</INF> 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 
SO<INF>2</INF> 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 SO<INF>2</INF> 
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 SO<INF>2</INF> planning 
that influence the suitability of alternative means of addressing the 
requirement in section 172(c)(9) for contingency measures for 
SO<INF>2</INF>, 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 SO<INF>2</INF> NAAQS and to undertake an aggressive follow-up 
for compliance and enforcement. See EPA's April 2014 SO<INF>2</INF> 
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 SO<INF>2</INF> NAAQS for the Detroit area and 
for meeting other nonattainment area planning requirements of CAA 
sections 110, 172, 179 and 192. This SO<INF>2</INF> 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 SO<INF>2</INF> 
attainment plan meets applicable requirements of sections 110, 172, 
179, and 192 of the CAA.
    Michigan's Detroit SO<INF>2</INF> 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 SO<INF>2</INF> emissions; 
Permit to Install 51-08C, governing EES Coke SO<INF>2</INF> emissions; 
Permit MI-ROP-A8640-2016a, governing Cleveland-Cliffs Steel Corporation 
SO<INF>2</INF> emissions; and Permit to Install 109-23 and the cover 
sheet, section 5.1d (SO<INF>2</INF> emission limit), and sections 5.2-
5.10 (Special Conditions) of Permit 253-02A, governing DIG 
SO<INF>2</INF> 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 (SO<INF>2</INF> 
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

[[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:
    <bullet> 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);
    <bullet> Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
    <bullet> 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.);
    <bullet> 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);
    <bullet> Does not have federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
    <bullet> Is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because it approves a state program;
    <bullet> Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001); and
    <bullet> 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


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