[Federal Register Volume 88, Number 56 (Thursday, March 23, 2023)]
[Proposed Rules]
[Pages 17488-17495]
[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

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,<PHONE_NUMBER>,
[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

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

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 <IP_ADDRESS> 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.

    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
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                                           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.
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                                               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
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                                                    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).
----------------------------------------------------------------------------------------------------------------

                                                     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

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

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]
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