[Federal Register Volume 88, Number 56 (Thursday, March 23, 2023)]
[Proposed Rules]
[Pages 17488-17495]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-05819]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R05-OAR-2022-0976; FRL-10788-01-R5]


Air Plan Approval; Michigan; Conditional Approval of the Detroit 
Sulfur Dioxide Nonattainment Area Plan

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
conditionally approve the State Implementation Plan (SIP) revision

[[Page 17489]]

submitted by Michigan on December 20, 2022, and supplemented on 
February 21, 2023, 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. If 
this action is finalized, EPA will propose to convert the conditional 
approval of the SIP revision to a full approval upon Michigan timely 
meeting its commitment to submit the issued permits.

DATES: Comments must be received on or before April 24, 2023.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-
OAR-2022-0976 at https://www.regulations.gov, or via email to 
[email protected]. For comments submitted at Regulations.gov, follow 
the online instructions for submitting comments. Once submitted, 
comments cannot be edited or removed from Regulations.gov. For either 
manner of submission, 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 (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, information about CBI or multimedia 
submissions, and general guidance on making effective comments, please 
visit https://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Abigail Teener, Environmental 
Engineer, Attainment Planning and Maintenance Section, Air Programs 
Branch (AR18J), Environmental Protection Agency, Region 5, 77 West 
Jackson Boulevard, Chicago, Illinois 60604, (312) 353-7314, 
[email protected]. The EPA Region 5 office is open from 8:30 a.m. 
to 4:30 p.m., Monday through Friday, excluding Federal holidays and 
facility closures due to COVID-19.

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 (RFP)
    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 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 Clean Air Act (CAA) directs states to submit SIPs for areas 
designated as nonattainment for the 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 will attain the NAAQS as 
expeditiously as practicable, but no later than 5 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 plan by the submittal 
deadline (81 FR 14736). Michigan submitted an attainment plan for the 
Detroit SO2 area on May 31, 2016, and submitted associated 
final enforceable measures on June 30, 2016. As part of its 2016 plan, 
Michigan imposed emission limits for U.S. Steel it concluded were 
necessary to bring the Detroit area into attainment via Michigan 
Administrative Code (MAC) 336.1430 (``Rule 430''). Michigan submitted 
Rule 430 to EPA as an enforceable limitation element for approval as 
part of its SO2 plan. Subsequently, U.S. Steel challenged 
Rule 430 under state law in the Michigan Court of Claims. The decision 
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 new source review (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 the requirements for meeting 
reasonable further progress (RFP) toward attainment of the NAAQS, 
reasonably available control measures and reasonably available control 
technology (RACM/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 which is permanently stopped only by meeting 
the conditions of EPA's regulations at 40 CFR 52.31(d).
    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 previous finding of failure to 
submit. However, it did not affect the sanctions clock started under 
CAA section 179 resulting from EPA's partial disapproval of the prior 
SIP, which would be permanently stopped only by meeting the conditions 
of EPA's regulations at 40 CFR 52.31(d)(5).
    While EPA's FIP for the Detroit area meets the requirements for 
SO2 nonattainment area plans, the FIP does not relieve 
Michigan of the requirement under Section 191 of the CAA to submit a 
plan that provides for attainment of the 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

[[Page 17490]]

March 19, 2021 rulemaking. Michigan's December 20, 2022, plan depends, 
in part, on permits that have not yet been issued but will include 
limits and associated requirements for the U.S. Steel 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.
    Under section 110(k)(4) of the CAA, EPA may conditionally approve a 
plan based on a commitment from the State to adopt specific enforceable 
measures within one year from the date of approval. EPA's October 28, 
1992, memorandum, entitled ``State Implementation Plan (SIP) Actions 
Submitted in Response to Clean Air Act (Act) Deadlines,'' states that 
such commitments should include a formal request that EPA approve the 
commitment, be subject to public hearing pursuant of 40 CFR 51.102, and 
include a schedule for the adoption of the required measures. 
Therefore, Michigan included in its December 20, 2022, submittal, which 
was subject to public hearing, a request that EPA conditionally approve 
its revised plan for the Detroit area, conditional upon the issuance 
and submission for incorporation into the SIP of the NSR permits for 
the U.S. Steel and DIG facilities, as well as a commitment to submit 
the permits to EPA within one year of a conditional approval. On 
February 21, 2023, Michigan submitted a letter clarifying the schedule 
for the conditional approval, including Michigan's commitment to submit 
the necessary permits by April 30, 2024, and the schedule Michigan 
expects to follow to meet that commitment. Michigan's expected schedule 
includes ensuring all necessary permit applications are submitted by 
March 31, 2023, beginning the 240-day permit review process by April 1, 
2023, issuing permits by December 1, 2023, and submitting permits to 
EPA by December 31, 2023. Michigan's expected date of submittal 
provides some cushion to ensure the State is able to meet its 
commitment to submit the permits by April 30, 2024, and EPA finds that 
Michigan's schedule is reasonable.
    If EPA finalizes this conditional approval, the State must meet its 
commitment to submit the necessary permits by April 30, 2024. If the 
State fails to do so, the action will become a disapproval. In such 
case, EPA will notify the State by letter of the disapproval and 
subsequently publish a document in the Federal Register notifying the 
public that the conditional approval automatically converted to a 
disapproval.
    If the State meets its commitment within the applicable time frame, 
the conditionally approved submission will remain a part of the SIP 
until EPA takes final action approving or disapproving the new 
submittal. If EPA disapproves the new submittal, Michigan's 
conditionally approved Detroit SO2 plan will also be 
disapproved at that time. If EPA approves the submittal, Michigan's 
Detroit SO2 plan will be fully approved in its entirety and 
replace the conditionally approved element in the SIP.
    Under 40 CFR 52.31(d)(2)(ii), if the State has submitted a revised 
plan to correct the deficiency, and EPA proposes to conditionally 
approve the plan and issues an interim final determination that the 
revised plan corrects the deficiency, application of the new source 
offset sanction shall be stayed and application of the highway sanction 
shall be deferred. However, if the State does not meet its commitment 
and the plan is disapproved, the new source offset sanction shall 
reapply and the highway sanction shall apply on the date of proposed or 
final disapproval. In the Detroit SO2 nonattainment area, 
the two-to-one new source offset sanction took effect on October 19, 
2022 (18 months following the effective date of March 19, 2021, 
rulemaking that triggered the sanctions clock), and the highway funding 
sanction was scheduled to take effect on April 19, 2023 (6 months after 
the date of the offset sanctions), as the result of the March 19, 2021, 
partial disapproval.
    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 conditional 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 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); NSR; 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 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 any applicable requirement concerning NAAQS 
attainment and RFP, or any other applicable requirement, and no 
requirement in effect (or required to be adopted by an order, 
settlement, agreement, or plan in effect before November 15, 1990) in 
any area which is a nonattainment area for any air pollutant, may be 
modified in any manner unless it ensures equivalent or greater emission 
reductions of such air pollutant.
    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. 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

[[Page 17491]]

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 
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 AERMOD 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 AERMET. 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).

III. Review of Michigan's Attainment Plan

    Michigan's plan for the Detroit nonattainment area mirrors EPA's 
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 federally enforceable, via 
either incorporation of permits containing the limits and requirements 
into Michigan's SIP or inclusion in the FIP regulatory language, 
codified at 40 CFR 52.1189. As Michigan's plan cannot rely on the FIP 
regulatory language, the enforceability 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). DTE Trenton Channel has since permanently shut down as of 
June 19, 2022, under court order.\1\ However, the DTE Trenton Channel 
permitted limit was included in the FIP analysis and included in 
Michigan's revised plan as a precautionary measure. The Carmeuse Lime 
and DTE Trenton Channel permits were incorporated into Michigan's SIP 
as part of EPA's March 19, 2021, action, so EPA is not proposing to re-
incorporate them into 40 CFR part 52 in this action.
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    \1\ See https://earthjustice.org/sites/default/files/files/267-1_-_sierra_club_-_dte_separate_agreement.pdf.
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    Emission limits and associated requirements for EES Coke and 
Cleveland-Cliffs Steel Corporation are contained in permits Permit to 
Install 51-08C, effective November 21, 2014, and Permit MI-ROP-A8640-
2016a, modified January 19, 2017, respectively. 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.

[[Page 17492]]

    Michigan has committed to issue permits for the emission limits and 
associated construction, monitoring, recordkeeping, and reporting 
requirements for the U.S. Steel and DIG units, including the 
construction of a new 170-foot stack for U.S. Steel Boilerhouse 2 by 
November 14, 2024, that are no less stringent than those specified in 
40 CFR 52. 1189. These enforceable requirements will be contained in 
permits or permit revisions that have not yet been issued, but that 
Michigan has committed to submit to EPA by April 30, 2024. While EPA 
cannot incorporate permits containing emission limits for the U.S. 
Steel and DIG unit limits into Michigan's SIP at this time, these 
limits were previously adopted into EPA's FIP and will continue to 
remain federally enforceable as part of the regulatory text of EPA's 
FIP, codified at 40 CFR 52.1189. Therefore, EPA is proposing to 
conditionally approve Michigan's plan, pending the issuance and timely 
submission of the appropriate permits to EPA for incorporation into the 
SIP.

               Table 1--Emission Limits Included in Michigan's Detroit SO2 Nonattainment Area Plan
----------------------------------------------------------------------------------------------------------------
                                           SO2 emission
                  Unit                    limit  (lb/hr)      Permit No. or status             SIP status
----------------------------------------------------------------------------------------------------------------
                                             U.S. Steel--Zug Island
----------------------------------------------------------------------------------------------------------------
Boilerhouse 1 (all stacks combined)....             55.00  Permit issuance in          If this action is
A1 Blast Furnace.......................              0.00   progress.                   finalized, approval of
B2 Blast Furnace.......................             40.18                               Michigan's plan will be
D4 Blast Furnace.......................             40.18                               conditional upon the
                                                                                        timely submission of
                                                                                        these permits for
                                                                                        incorporation into the
                                                                                        SIP.
A/B Blas Furnace Flares................             60.19
D Furnace Flare........................             60.19
Boilerhouse 2..........................    * 750.00/81.00  Permit issuance in
                                                            progress.
----------------------------------------------------------------------------------------------------------------
                                               U.S. Steel--Ecorse
----------------------------------------------------------------------------------------------------------------
Hot Strip Mill--Slab Reheat Furnace 1..              0.31  Permit issuance in          If this action is
Hot Strip Mill--Slab Reheat Furnace 2..              0.31   progress.                   finalized, approval of
Hot Strip Mill--Slab Reheat Furnace 3..              0.31                               Michigan's plan will be
Hot Strip Mill--Slab Reheat Furnace 4..              0.31                               conditional upon the
                                                                                        timely submission of
                                                                                        this permit for
                                                                                        incorporation into the
                                                                                        SIP.
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
                                                                                        incorporate this permit
                                                                                        into Michigan's SIP.
----------------------------------------------------------------------------------------------------------------
                                             DTE Trenton Channel **
----------------------------------------------------------------------------------------------------------------
Trenton Channel Unit 9.................             5,907  Permit to Install 125-11C.  Incorporated into
                                                                                        Michigan's SIP as part
                                                                                        of March 19, 2021 action
                                                                                        (86 FR 14827). However,
                                                                                        the source has since
                                                                                        shut down.
----------------------------------------------------------------------------------------------------------------
                                                  Carmeuse Lime
----------------------------------------------------------------------------------------------------------------
Carmeuse Lime Stack....................               470  Permit to Install 193-14A.  Incorporated into
                                                                                        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                               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).
----------------------------------------------------------------------------------------------------------------

[[Page 17493]]

 
                                                     DIG **
----------------------------------------------------------------------------------------------------------------
Boilers 1, 2, and 3 (combined).........               420  Permit issuance in          If this action is
Boilers 1, 2, and 3 and Flares 1 and 2                840   progress.                   finalized, approval of
 (combined).                                                                            Michigan's plan will be
                                                                                        conditional upon the
                                                                                        timely submission of
                                                                                        this permit for
                                                                                        incorporation into the
                                                                                        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 will also require 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.

    If this action is finalized and Michigan fails to submit the 
permits containing the necessary requirements for the U.S. Steel and 
DIG units, the action will become a disapproval one year from the date 
of final conditional approval. If EPA disapproves the new submittal, 
Michigan's conditionally approved Detroit SO2 plan will also 
be disapproved at that time. Additionally, the new source offset 
sanction shall reapply and the highway sanction shall apply on the date 
of proposed or final disapproval.
    Michigan commits to issue permits that contain requirements that 
are no less stringent than EPA's FIP, codified at 40 CFR 52.1189. 
Because Michigan's commitment relies on the same modeling analysis that 
supports EPA's FIP and will contain emission limits and associated 
requirements that are no less stringent that EPA's FIP, EPA is 
proposing to conditionally approve Michigan's plan, conditional upon 
the timely submission of permits containing the necessary 
SO2 emission limits and associated requirements for the U.S. 
Steel and DIG units.

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. 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.
    In its March 19, 2021, rulemaking, EPA disapproved Michigan's 2016 
attainment plan because it relied on Rule 430, which was invalidated 
and so was no longer an enforceable 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 emissions limitations or control measures.
    EPA's FIP for attaining the 1-hour SO2 NAAQS in the 
Detroit area is 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 allows time for the owner or operator to submit a construction permit 
application to the State of Michigan (required by February 12, 2023), 
as well as time for the State of Michigan to issue the permit, 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 the Michigan's plan satisfies 
the requirement in sections 172(c)(1) and (6) to adopt and submit all 
RACM/RACT and emissions limitations or control measures as needed to 
attain the standards as expeditiously as practicable.

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

[[Page 17494]]

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 V.B above, the 2-year compliance schedule for U.S. Steel 
Boilerhouse 2 allows 90 days for the owner or operator to submit a 
construction permit application to the State of Michigan, as well as 
time for the State of Michigan to issue the permit, 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 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 conditionally approve Michigan's revised SIP 
submission, which the State submitted to EPA on December 20, 2022, for 
attaining the 2010 1-hour SO2 NAAQS for the Detroit area and 
for meeting other nonattainment area planning requirements, pending the 
timely submission of permits containing emission limits for the U.S. 
Steel and DIG facilities. This SO2 attainment plan includes 
Michigan's attainment demonstration for the Detroit area. The plan also 
addresses requirements for RFP, RACT/RACM, 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 plan 
meets applicable requirements of section 172 of the CAA, conditioned 
upon the timely submission of the appropriate permits.
    Michigan's Detroit SO2 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 EES Coke limits specified in Permit to Install 51-08C, Cleveland-
Cliffs Steel Corporation emission limits specified in Permit MI-ROP-
A8640-2016a, and U.S. Steel and DIG limits that will be included in 
permits that Michigan has committed to submit for incorporation into 
Michigan's SIP by April 30, 2024. Regardless of whether these permits 
are incorporated into Michigan's SIP, the U.S. Steel and DIG limits 
will remain federally enforceable in EPA's FIP, codified at 40 CFR 
52.1189, until further action. The Carmeuse Lime and DTE Trenton 
Channel permits have already been incorporated into Michigan's SIP and 
EPA is not proposing to re-incorporate them into 40 CFR part 52 here. 
EPA is proposing to incorporate Permit to Install 51-08C, governing EES 
Coke SO2 emissions and Permit MI-ROP-A8640-2016a, governing 
Cleveland-Cliffs Steel Corporation SO2 emissions into 
Michigan's SIP in this action.
    If EPA finalizes this conditional approval, the State must meet its 
commitment to submit the necessary permits by April 30, 2024. If the 
State fails to do so, the action will become a disapproval one year 
from the date of final conditional approval. In such case, EPA will 
notify the State by letter of the disapproval and subsequently publish 
a document in the Federal Register notifying the public that the 
conditional approval automatically converted to a disapproval.
    If the State meets its commitment within the applicable time frame, 
the conditionally approved submission will remain a part of the SIP 
until EPA takes final action approving or disapproving the new permits. 
If EPA disapproves the new submittal, Michigan's conditionally approved 
Detroit SO2 plan will also be disapproved at that time. If 
EPA approves the submittal, Michigan's Detroit SO2 plan will 
be approved in its entirety and replace the conditionally approved 
element in the SIP.
    Under 40 CFR 52.31(d)(2)(ii), if the State has submitted a revised 
plan to correct the deficiency, and EPA proposes to conditionally 
approve the plan and issues an interim final determination that the 
revised plan corrects the deficiency, application of the new source 
offset sanction shall be stayed and application of the highway sanction 
shall be deferred. However, if the State does not meet its commitment 
and the plan is disapproved, the new source offset sanction shall 
reapply and the highway sanction shall apply on the date of proposed or 
final disapproval. In the Detroit area, the offset sanction was imposed 
on October 19, 2022, and the highway sanction, if not deferred, would 
be imposed on April 19, 2022.
    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 Permit to Install 51-08C, effective November 21, 2014, 
governing EES Coke SO2 emissions and Permit MI-ROP-A8640-
2016a, modified January 19, 2017, governing Cleveland-Cliffs Steel 
Corporation SO2 emissions, as 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 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

[[Page 17495]]

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 13563 (76 FR 3821, January 21, 2011);
     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 in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive 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, 
Feb. 16, 1994) directs Federal agencies to identify and address 
``disproportionately high and adverse human health or environmental 
effects'' of their actions on minority populations and low-income 
populations to the greatest extent practicable and permitted by law. 
EPA defines environmental justice (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.''
    The air agency did not evaluate environmental justice 
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 
environmental justice for people of color, low-income populations, and 
Indigenous peoples.

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: March 16, 2023.
Debra Shore,
Regional Administrator, Region 5.
[FR Doc. 2023-05819 Filed 3-22-23; 8:45 am]
BILLING CODE 6560-50-P