[Federal Register Volume 91, Number 143 (Tuesday, July 28, 2026)]
[Proposed Rules]
[Pages 47162-47174]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-15168]
=======================================================================
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 52 and 81
[EPA-R05-OAR-2022-0004; FRL-13415-01-R5]
Air Plan Approval; Michigan; Redesignation of the Detroit, MI
Area to Attainment of the 2015 Ozone Standards
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve a request from the Michigan Department of Environment, Great
Lakes, and Energy (EGLE) to redesignate the Detroit, Michigan area to
attainment for the 2015 ozone National Ambient Air Quality Standards
(NAAQS) because the request meets the statutory requirements for
redesignation under the Clean Air Act (CAA). EGLE submitted this
request on January 3, 2022, and submitted a supplement to this request
on May 18, 2026. The EPA is also proposing to approve, as a revision to
the Michigan State Implementation Plan (SIP), the State's updated
maintenance plan for the 2015 ozone NAAQS through 2040 in the Detroit
area, including motor vehicle emissions budgets for 2035 and 2040, for
both volatile organic compound (VOC) and oxides of nitrogen
(NOX). The EPA is also initiating the adequacy process for
these maintenance plan budgets. Additionally, the EPA is proposing to
adjust the SIP submission and control measure implementation deadlines
for certain Moderate requirements. Finally, the EPA is proposing to
take final agency action on an exceptional events request submitted by
EGLE on April 15, 2026, and concurred on by the EPA on June 4, 2026.
DATES: Comments must be received on or before August 27, 2026.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-
OAR-2022-0004 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 the docket. The EPA may
publish any comment received to its public docket. Do not submit to the
EPA's docket at https://www.regulations.gov any information you
consider to be Confidential Business Information (CBI), Proprietary
Business Information (PBI), or other information whose disclosure is
restricted by statute. Multimedia submissions (audio, video, etc.) must
be accompanied by a written comment. The written comment is considered
the official comment and should include discussion of all points you
wish to make. The 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, PBI, or multimedia submissions, and general
guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
FOR FURTHER INFORMATION CONTACT: Eric Svingen, Air and Radiation
Division (AR-18J), Environmental Protection Agency, Region 5, 77 West
Jackson Boulevard, Chicago, Illinois 60604, telephone number: (312)
353-4489, email address: [email protected].
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean the EPA. We use multiple acronyms
and terms in this preamble. While this list may not be exhaustive, to
ease the reading of this preamble and for reference purposes, the EPA
defines the following terms and acronyms here:
AQS Air Quality System
CAA Clean Air Act
CBI Confidential Business Information
CERR Consolidated Emissions Reporting Rule
CTG Control Technology Guideline
DVs Design Values
EGLE Michigan Department of Environment, Great Lakes, and Energy
EPA Environmental Protection Agency
GHG Greenhouse Gas
I/M Inspection and Maintenance
NAAQS National Ambient Air Quality Standards
NOX Oxides of Nitrogen
NSR New Source Review
PBI Proprietary Business Information
PM2.5 Fine Particulate Matter
ppm Parts per Million
PSD Prevention of Significant Deterioration
RACM Reasonably Available Control Measures
RACT Reasonably Available Control Technology
RFP Reasonable Further Progress
SEMCOG Southeast Michigan Council of Governments
SIP State Implementation Plan
VMT Vehicle Miles of Travel
VOC Volatile Organic Compound
Organization of this document. The information presented in this
preamble is organized as follows:
I. What is the EPA proposing?
II. What is the background for these actions?
III. What are the criteria for redesignation?
IV. What is the EPA's analysis of Michigan's redesignation request?
A. Has the Detroit area attained the 2015 ozone NAAQS?
1. Exceptional Events Demonstration
2. Monitoring Data
B. Has Michigan met all applicable requirements of section 110
and part D of the CAA for the Detroit area, and does Michigan have a
fully approved SIP for the area under section 110(k) of the CAA?
1. Michigan Has Met All Applicable Requirements of Section 110
and Part D of the CAA Applicable to the Detroit Area for Purposes of
Redesignation
a. Section 110 General Requirements for Implementation Plans
b. Part D Requirements
i. Section 172 Requirements
ii. Section 176 Conformity Requirements
iii. CAA Section 182(a), Section 182(b), and Section 182(f)
Requirements
2. The Detroit Area Has a Fully Approved SIP for Purposes of
Redesignation Under Section 110(k) of the CAA
C. Are the air quality improvements in the Detroit area due to
permanent and enforceable emission reductions?
D. Does Michigan have a fully approvable ozone maintenance plan
for the Detroit area?
1. Attainment Inventory
2. Has the State demonstrated maintenance of the ozone standard
in the Detroit area?
3. Continued Air Quality Monitoring, Verification of Continued
Attainment, and Contingency Plan
V. Has the State adopted approvable motor vehicle emission budgets?
A. Motor Vehicle Emission Budgets
B. What is a safety margin?
VI. Adjustment of Certain SIP Submittal and Implementation Deadlines
A. Sixth Circuit Court of Appeals Decision in Sierra Club v. EPA
B. Proposed Adjustment of Certain SIP Submittal and
Implementation Deadlines Associated With the Moderate Classification
VII. Adjustment of Basic I/M Implementation Deadline
VIII. What action is the EPA taking?
IX. Statutory and Executive Order Reviews
[[Page 47163]]
I. What is the EPA proposing?
The EPA is proposing to take several related actions. The EPA
proposes to determine that the Detroit area has met the requirements
for redesignation under CAA section 107(d)(3)(E), and the EPA is thus
proposing to change the legal designation of the Detroit area from
nonattainment to attainment for the 2015 ozone NAAQS. The EPA is also
proposing to approve, as a revision to the Michigan SIP, the State's
updated maintenance plan for the area, which is intended to ensure
attainment of the 2015 ozone NAAQS through 2040 in the Detroit area. As
part of the maintenance plan, the EPA is proposing to approve the newly
established 2035 and 2040 motor vehicle emissions budgets for the
Detroit area. The EPA is also initiating the adequacy process for these
budgets. Additionally, the EPA is proposing to adjust the deadline for
Michigan to submit SIP revisions for the Detroit area for requirements
associated with the Moderate classification, as well as the deadline to
implement these measures except for Basic vehicle inspection and
maintenance (I/M), to no later than December 5, 2026. The EPA is
proposing to adjust the deadline for Michigan to implement Basic I/M in
the Detroit area to no later than December 5, 2030. The EPA also
proposes to take final agency action on an exceptional events request
submitted by EGLE on April 15, 2026, and concurred on by the EPA on
June 4, 2026.
II. What is the background for these actions?
Under CAA section 109, the EPA has established NAAQS for certain
air pollutants and conducts periodic reviews of the NAAQS to determine
whether they should be revised or whether new NAAQS should be
established. One such criteria pollutant is ground-level ozone.\1\ On
October 1, 2015, the EPA promulgated a revised 8-hour ozone NAAQS of
0.070 parts per million (ppm).\2\ In accordance with appendix U of 40
CFR part 50, the 2015 ozone NAAQS is attained in an area when the 3-
year average of the annual fourth highest daily maximum 8-hour average
concentration is equal to or less than 0.070 ppm, when truncated after
the thousandth decimal place, at all of the ozone monitoring sites in
the area.\3\
---------------------------------------------------------------------------
\1\ The EPA has primary and secondary standards for NAAQS, but
they have always been the same for ozone. The primary NAAQS
represent ambient air quality standards which the EPA has determined
are necessary to protect the public health with an adequate margin
of safety. The secondary NAAQS represent ambient air quality
standards which the EPA has determined are requisite to protect the
public welfare from any known or anticipated adverse effects
associated with the presence of such air pollutant in the ambient
air.
\2\ See 80 FR 65292 (October 26, 2015).
\3\ See 40 CFR 50.19 and appendix U to 40 CFR part 50.
---------------------------------------------------------------------------
Upon promulgation of a new or revised NAAQS, section 107(d)(1)(B)
of the CAA requires the EPA to designate as nonattainment any areas
that are violating the NAAQS, based on the most recent three years of
quality assured ozone monitoring data. The Detroit area was initially
designated as a Marginal nonattainment area for the 2015 ozone NAAQS on
June 4, 2018, with an effective date of August 3, 2018.\4\ The Detroit
area includes Livingston, Macomb, Monroe, Oakland, St. Clair,
Washtenaw, and Wayne Counties.
---------------------------------------------------------------------------
\4\ See 83 FR 25776 (June 4, 2018).
---------------------------------------------------------------------------
Since the 2018 initial designation, the designation and
classification of Detroit have been addressed by several submittals by
EGLE and actions by the EPA:
2022 submittal: ``Request for Redesignation to Attainment
and Submittal to the State Implementation Plan (SIP) for the Clean Air
Act (CAA) Section 175A Maintenance Plan for the Southeast Michigan 2015
Ozone Nonattainment Area'' (January 3, 2022)
2022 proposed redesignation: ``Redesignation of the
Detroit, MI Area to Attainment of the 2015 Ozone Standards'' (87 FR
14210, March 14, 2022)
2022 proposed reclassification: ``Determinations of
Attainment by the Attainment Date, Extensions of the Attainment Date,
and Reclassification of Areas Classified as Marginal for the 2015 Ozone
National Ambient Air Quality Standards'' (87 FR 21842, April 13, 2022)
2023 final reclassification: ``Finding of Failure To
Attain and Reclassification of the Detroit Area as Moderate for the
2015 Ozone National Ambient Air Quality Standards'' (88 FR 6633,
February 1, 2023)
2023 proposed clean data determination: ``Clean Data
Determination for the Detroit Area for the 2015 Ozone Standard'' (88 FR
7382, February 3, 2023)
2023 final clean data determination: ``Clean Data
Determination for the Detroit Area for the 2015 Ozone Standard'' (88 FR
32584, May 19, 2023)
2023 final redesignation: ``Redesignation of the Detroit,
MI Area to Attainment of the 2015 Ozone Standards'' (88 FR 32594, May
19, 2023)
2026 supplemental submittal: ``Addendum to the Request for
Redesignation to Attainment for the 2015 Ozone National Ambient Air
Quality Standard and Revision to Michigan's State Implementation Plan
and Ozone Maintenance Plan for Southeast Michigan Ozone Nonattainment
Area'' (May 18, 2026)
2026 technical amendment: ``Technical Amendment'' (91 FR
31953, May 29, 2026)
2026 proposed determination of attainment by the
attainment date: ``Determination of Attainment by the Attainment Date
for the 2015 Ozone Standards'' (91 FR 31993, May 29, 2026)
In its 2022 submittal, EGLE requested that the EPA redesignate the
Detroit area to attainment of the 2015 ozone NAAQS based on attaining
air quality monitoring data for the 2019-2021 period. In the 2023 final
reclassification, the EPA determined that the Detroit area did not
attain the standard by the Marginal attainment date based on monitoring
data from the 2018-2020 period, and the area was reclassified to
Moderate by operation of law. In the 2023 clean data determination, the
EPA found that the Detroit area was attaining the 2015 ozone NAAQS
based on monitoring data from the 2020-2022 period. In the 2023
redesignation, the EPA approved the request from EGLE to redesignate
the area to attainment for the 2015 ozone NAAQS.
On July 17, 2023, Sierra Club petitioned the United States Court of
Appeals for the Sixth Circuit (Court) for review of the 2023 final
clean data determination and 2023 final redesignation. On December 5,
2025, the Court upheld the EPA's clean data determination and,
regarding the redesignation, concluded that the EPA erred only with
respect to its legal interpretation of CAA section 107(d)(3)(E)(v),
which requires that a State ``has met'' all requirements applicable to
the area as a prerequisite to redesignation. The Court vacated the
EPA's redesignation of the Detroit area and issued its mandate in the
case on February 24, 2026.\5\ The other EPA actions taken in the 2023
final clean data determination and 2023 final redesignation were not
affected by the 2025 Sixth Circuit decision.
---------------------------------------------------------------------------
\5\ See Sierra Club v. EPA, 161 F.4th 934 (6th Cir. 2025).
---------------------------------------------------------------------------
III. What are the criteria for redesignation?
Section 107(d)(3)(E) of the CAA allows redesignation of an area to
attainment of the NAAQS provided that: (1) the Administrator (EPA)
determines that the area has attained the NAAQS; (2) the Administrator
has fully approved the applicable implementation plan for the area
under section 110(k) of the CAA; (3) the Administrator determines
[[Page 47164]]
that the improvement in air quality is due to permanent and enforceable
reductions in emissions resulting from implementation of the applicable
SIP, applicable Federal air pollutant control regulations, and other
permanent and enforceable emission reductions; (4) the Administrator
has fully approved a maintenance plan for the area as meeting the
requirements of section 175A of the CAA; and (5) the State containing
the area has met all requirements applicable to the area for the
purposes of redesignation under section 110 and part D of the CAA.
On April 16, 1992 (57 FR 13498), the EPA provided guidance on
redesignations in the General Preamble for the Implementation of title
I of the CAA Amendments of 1990 and supplemented this guidance on April
28, 1992 (57 FR 18070). The EPA has provided further guidance on
processing redesignation requests in policy memoranda, including the
Calcagni Memorandum.\6\
---------------------------------------------------------------------------
\6\ See the September 4, 1992, memorandum from John Calcagni,
Director, Air Quality Management Division, entitled ``Procedures for
Processing Requests to Redesignate Areas to Attainment.''
---------------------------------------------------------------------------
IV. What is the EPA's analysis of Michigan's redesignation request?
A. Has the Detroit area attained the 2015 ozone NAAQS?
For redesignation of a nonattainment area to attainment, CAA
section 107(d)(3)(E)(i) requires the EPA to determine that the area has
attained the applicable NAAQS. An area is attaining the 2015 ozone
NAAQS if the most recent design values (DVs) at all ambient air quality
monitoring sites in the area are less than or equal to 0.070 ppm. The
DV at an ambient air quality monitoring site is the 3-year average of
the annual 4th highest daily maximum 8-hour average ozone
concentrations, as specified in appendix U to 40 CFR part 50. Ozone DVs
are based on the three most recent, complete,\7\ consecutive years of
quality-assured and certified air quality monitoring data meeting all
applicable requirements in 40 CFR part 58 and reported to the EPA's Air
Quality System (AQS) database.
---------------------------------------------------------------------------
\7\ An ozone DV is valid if daily maximum 8-hour average
concentrations are available for at least 90% of the days within the
ozone monitoring seasons on average, for the 3-year period, with a
minimum data completeness of 75% during the ozone monitoring season
of any year during the 3-year period. See section 4 of appendix U to
40 CFR part 50. The ozone season is defined by State in 40 CFR 58,
appendix D. The ozone season for Michigan is March 1st to October
31st. See 80 FR 65292, 65466 through 65467 (October 26, 2015).
---------------------------------------------------------------------------
1. Exceptional Events Demonstration
Congress has recognized that it may not be appropriate for the EPA
to use certain monitoring data collected by the ambient air quality
monitoring network and maintained in the EPA's AQS database in certain
regulatory determinations. Thus, in 2005, Congress provided the
statutory authority for the exclusion of data influenced by
``exceptional events'' meeting specific criteria by adding section
319(b) to the CAA.\8\
---------------------------------------------------------------------------
\8\ Under CAA section 319(b), an exceptional event means an
event that (i) affects air quality; (ii) is not reasonably
controllable or preventable; (iii) is an event caused by human
activity that is unlikely to recur at a particular location or a
natural event; and (iv) is determined by the EPA under the process
established in regulations promulgated by the EPA in accordance with
section 319(b)(2) to be an exceptional event. For the purposes of
section 319(b), an exceptional event does not include (i) stagnation
of air masses or meteorological inversions; (ii) a meteorological
event involving high temperatures or lack of precipitation; or (iii)
air pollution relating to source noncompliance.
---------------------------------------------------------------------------
To implement this 2005 CAA amendment, on March 22, 2007 (72 FR
13560), the EPA promulgated the 2007 Exceptional Events Rule. The 2007
Exceptional Events Rule created a regulatory process codified at 40 CFR
parts 50 and 51 (sections 50.1, 50.14 and 51.930). These regulatory
sections, which superseded the EPA's previous guidance on handling data
influenced by events, contain definitions, procedural requirements,
requirements for air agency demonstrations, criteria for the EPA's
approval of the exclusion of event-affected air quality data from the
data set used for regulatory decisions, and requirements for air
agencies to take appropriate and reasonable actions to protect public
health from exceedances or violations of the NAAQS. On October 3, 2016
(81 FR 68216), the EPA promulgated a comprehensive revision to the 2007
Exceptional Events Rule. The 2016 Exceptional Events Rule revision
included the requirement that, if a State demonstrates that emissions
from a wildfire smoke event caused a specific air pollution
concentration in excess of the NAAQS at a particular air quality
monitoring location and otherwise satisfies the requirements of 40 CFR
50.14, the EPA must exclude that data from use in determinations of
exceedances and violations.\9\
---------------------------------------------------------------------------
\9\ 40 CFR 50.14(b)(4).
---------------------------------------------------------------------------
For the purposes of this proposed action, on April 15, 2026, EGLE
submitted an exceptional events demonstration to show that ozone
concentrations recorded at the Oakland County monitor at Oak Park with
Site ID 26-125-0001 and the St. Clair County monitor at Port Huron with
Site ID 26-147-0005 on June 29 and June 30, 2023, and July 15, 2025,
were influenced by wildfires. The EPA concurred on this request on June
4, 2026.
The EPA found that Michigan's demonstration met the Exceptional
Events Rule criteria and determined that these wildfire events had
regulatory significance for purposes of calculating the area's most
recent DV to demonstrate the area is attaining the standard in order to
redesignate the area to attainment for the 2015 ozone NAAQS. As such,
the EPA now proposes to take final regulatory action on the concurred
dates, as detailed in the docket, as exceptional events to be removed
from the data set used for regulatory purposes. For this proposed
action, the EPA will rely on the calculated DVs that exclude the event-
influenced data for the purpose of demonstrating attainment of the 2015
ozone NAAQS. Further details on Michigan's analyses and the EPA's
concurrence can be found in the docket for this regulatory action.
While the EPA has concurred with Michigan's request to exclude
event-influenced air quality monitoring data from regulatory decisions,
these regulatory actions require the EPA to provide an opportunity for
public comment on the claimed exceptional events and all supporting
data prior to the EPA taking final agency action. This proposed action
provides the public with an opportunity to comment on the claimed
exceptional events, all supporting documents and the EPA's concurrence
with Michigan's request.
2. Monitoring Data
In its 2022 submittal, EGLE requested that the EPA redesignate the
Detroit area to attainment of the 2015 ozone NAAQS based on attaining
air quality monitoring data for the 2019 through 2021 period. The EPA
is proposing to determine that the Detroit area has attained the 2015
ozone NAAQS based on monitoring data for the 2019 through 2021 period.
The EPA interprets CAA section 107(d)(3)(E)(i) to require continued
attainment until the EPA's final action redesignating a nonattainment
area. The EPA will not take final action to determine that the Detroit
area is attaining the NAAQS nor to approve the redesignation of this
area if the DV of any ozone monitoring site in the area violates the
NAAQS prior to final approval of the redesignation. As discussed in
section IV.D.3. of this preamble, EGLE has committed to continue
monitoring ozone in this area
[[Page 47165]]
to verify maintenance of the 2015 ozone NAAQS.
In the EPA's 2023 final clean data determination and 2023 final
redesignation, the EPA found that the Detroit area attained for the
2019 through 2021 and 2020 through 2022 periods. In the 2025 Sixth
Circuit decision, the Court upheld the EPA's finding that the area
attained for the 2019 through 2021 and 2020 through 2022 periods. In
the 2026 proposed determination of attainment by the attainment date,
the EPA proposed to determine that the area attained for the 2021
through 2023 period, and the EPA will not finalize this redesignation
until it has finalized the separate determination for the 2021 through
2023 period.
---------------------------------------------------------------------------
\10\ The ozone DV for the monitoring site with the highest 3-
year averaged concentration.
---------------------------------------------------------------------------
The EPA has additionally reviewed the available ozone monitoring
data from EGLE's monitoring sites in the Detroit area for the 2022
through 2024 and 2023 through 2025 periods. These data have been
quality assured, are recorded in the AQS, and were certified in advance
of the EPA's publication of this proposal. These data demonstrate that
the Detroit area is attaining the 2015 ozone NAAQS. The annual fourth-
highest daily maximum 8-hour average ozone concentrations and the 3-
year averages of these values (ozone DVs) for all monitoring sites are
summarized in Table 1.
Table 1--Annual Fourth-Highest Daily Maximum 8-Hour Ozone Concentrations and 3-Year Averages (DVs) for the Detroit Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
2022 through 2023 through
County Monitor 2022 4th high 2023 4th high 2024 4th high 2025 4th high 2024 average 2025 average
(ppm) (ppm) (ppm) (ppm) (ppm) (ppm)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Macomb.................................. 26-099-0009 0.066 0.072 0.070 0.066 0.069 0.069
26-099-1003 0.068 0.073 0.067 0.070 0.069 0.070
Oakland................................. 26-125-0001 0.065 0.073 0.069 0.069 0.069 0.070
St. Clair............................... 26-147-0005 0.066 0.071 0.068 0.069 0.068 0.069
Washtenaw............................... 26-161-0008 0.067 0.073 0.064 0.070 0.068 0.069
26-161-9991 0.066 0.072 0.060 0.063 0.066 0.065
Wayne................................... 26-163-0001 0.071 0.069 0.070 0.067 0.070 0.068
26-163-0019 0.067 0.071 0.068 0.070 0.068 0.069
--------------------------------------------------------------------------------------------------------------------------------------------------------
The Detroit area's 3-year ozone DVs for 2022 through 2024 and 2023
through 2025 are 0.070 ppm,\10\ which meet the 2015 ozone NAAQS.
Therefore, in this action, the EPA proposes to determine that the
Detroit area is attaining the 2015 ozone NAAQS.
B. Has Michigan met all applicable requirements of section 110 and part
D of the CAA for the Detroit area, and does Michigan have a fully
approved SIP for the area under section 110(k) of the CAA?
For redesignation of an area from nonattainment to attainment of a
NAAQS, CAA section 107(d)(3)(E)(v) requires the EPA to determine that
the State has met all applicable requirements under section 110 and
part D of title I of the CAA, and CAA section 107(d)(3)(E)(ii) requires
the EPA to determine that the State has a fully approved SIP under
section 110(k) of the CAA. The EPA proposes to find that Michigan has
met all applicable SIP requirements for purposes of redesignation under
section 110 and part D of title I of the CAA (requirements specific to
nonattainment areas for the 2015 ozone NAAQS). Additionally, the EPA
proposes to find that Michigan has a fully approved SIP under section
110(k) of the CAA. In making these proposed determinations, the EPA
ascertained which requirements are applicable for purposes of
redesignation, and whether the required Michigan SIP elements are fully
approved under section 110(k) and part D of the CAA. As discussed more
fully below, SIPs must be fully approved only with respect to these
applicable requirements of the CAA.
In the 2023 final clean data determination, the EPA determined that
the requirement for Michigan to submit certain planning SIPs related to
attainment of the area, including the reasonably available control
measures (RACM) requirement of section 172(c)(1) of the CAA, the
reasonable further progress (RFP) and attainment demonstration
requirements of sections 172(c)(2) and (6) and 182(b)(1) of the CAA,
and the requirement for contingency measures of section 172(c)(9) of
the CAA, would not be applicable to the area as long as it continues to
attain the NAAQS and would cease to apply upon redesignation. In
addition, in the context of redesignations, the EPA has interpreted
requirements related to attainment as not applicable for purposes of
redesignation. For example, in the General Preamble, the EPA stated
that the section 172(c)(9) requirements are directed at ensuring RFP
and attainment by the applicable date. These requirements no longer
apply when an area has attained the standard and is eligible for
redesignation. Furthermore, section 175A for maintenance plans provides
specific requirements for contingency measures that effectively
supersede the requirements of section 172(c)(9) for these areas.
(General Preamble, 57 FR 13498, 13564, April 16, 1992).\11\
---------------------------------------------------------------------------
\11\ See also Calcagni Memorandum at 6 (``The requirements for
reasonable further progress and other measures needed for attainment
will not apply for redesignations because they only have meaning for
areas not attaining the standard'').
---------------------------------------------------------------------------
1. Michigan Has Met All Applicable Requirements of Section 110 and Part
D of the CAA Applicable to the Detroit Area for Purposes of
Redesignation
a. Section 110 General Requirements for Implementation Plans
Section 110(a)(2) of the CAA delineates the general requirements
for a SIP. Section 110(a)(2) provides that the SIP must have been
adopted by the State after reasonable public notice and hearing, and
that, among other things, it must: (1) include enforceable emission
limitations and other control measures, means, or techniques necessary
to meet the requirements of the CAA; (2) provide for establishment and
operation of appropriate devices, methods, systems, and procedures
necessary to monitor ambient air quality; (3) provide for
implementation of a source permit program to regulate the modification
and construction of stationary sources within the areas covered by the
plan; (4) include provisions for the implementation of part C
prevention of significant deterioration (PSD) and part
[[Page 47166]]
D new source review (NSR) permit programs; (5) include provisions for
stationary source emission control measures, monitoring, and reporting;
(6) include provisions for air quality modeling; and, (7) provide for
public and local agency participation in planning and emission control
rule development.
Section 110(a)(2)(D) of the CAA requires SIPs to contain measures
to prevent sources in a State from significantly contributing to air
quality problems in another State. To implement this provision, the EPA
has required certain States to establish programs to address transport
of certain air pollutants, for example, the NOX SIP Call and
the Cross State Air Pollution Rule. However, like many of the section
110(a)(2) requirements, the section 110(a)(2)(D) SIP requirements are
not linked with a particular area's ozone designation and
classification. The EPA concludes that the SIP requirements linked with
the area's ozone designation and classification are the relevant
measures to evaluate when reviewing a redesignation request for the
area. The section 110(a)(2)(D) requirements, where applicable, continue
to apply to a State regardless of the designation of any one particular
area within the State. Thus, we believe these requirements are not
applicable requirements for purposes of redesignation.\12\
---------------------------------------------------------------------------
\12\ See 65 FR 37879, 37890 (June 19, 2000), 66 FR 53094
(October 19, 2001), 68 FR 25418, 25426-25427 (May 12, 2003).
---------------------------------------------------------------------------
In addition, the EPA believes that other section 110 elements that
are neither connected with nonattainment plan submissions nor linked
with an area's ozone attainment status are not applicable requirements
for purposes of redesignation. The area will still be subject to these
requirements after the area is redesignated to attainment of the 2015
ozone NAAQS. The section 110 and part D requirements which are linked
with a particular area's designation and classification are the
relevant measures to evaluate in reviewing a redesignation request.
This approach is consistent with the EPA's existing policy on
applicability (i.e., for redesignations) of conformity requirements, as
well as with section 184 ozone transport requirements.\13\
---------------------------------------------------------------------------
\13\ See Reading, Pennsylvania proposed and final rulemakings,
61 FR 53174 (October 10, 1996) and 62 FR 24826 (May 7, 1997);
Cleveland-Akron-Loraine, Ohio final rulemaking, 61 FR 20458 (May 7,
1996); and Tampa, Florida final rulemaking, 60 FR 62748 (December 7,
1995). See also the discussion of this issue in the Cincinnati, Ohio
ozone redesignation, 65 FR 37879, 37890 (June 19, 2000), and the
Pittsburgh, Pennsylvania ozone redesignation 66 FR 53094 (October
19, 2001).
---------------------------------------------------------------------------
We have reviewed Michigan's SIP and propose to find that it meets
the general SIP requirements under section 110 of the CAA, to the
extent those requirements are applicable for purposes of redesignation.
In any case, on September 28, 2021 (86 FR 53550), the EPA approved
elements of the SIP submitted by Michigan to meet the requirements of
section 110 for the 2015 ozone standard.
b. Part D Requirements
Section 172(c) of the CAA sets forth the basic requirements of air
quality plans for States with nonattainment areas that are required to
submit them pursuant to section 172(b). Subpart 2 of part D, which
includes section 182 of the CAA, establishes specific requirements for
ozone nonattainment areas depending on the areas' nonattainment
classifications.
The Detroit area is classified as Moderate under subpart 2 for the
2015 ozone NAAQS. As such, the area is subject to the subpart 1
requirements contained in section 172(c) and section 176. Similarly,
the area is subject to the subpart 2 requirements contained in section
182(a) (Marginal nonattainment area requirements) and section 182(b)
(Moderate nonattainment area requirements). A thorough discussion of
the requirements contained in section 172(c) and 182 can be found in
the General Preamble for Implementation of title I, 57 FR 13498 (April
16, 1992). However, as discussed in section VI of this preamble, the
EPA is proposing to adjust the deadline for Michigan to submit Moderate
SIP revisions for the Detroit area to no later than December 5, 2026.
Providing the EPA finalizes this SIP submittal deadline adjustment and
the redesignation of the Detroit area prior to December 5, 2026,
Moderate SIP requirements would not be applicable requirements for
purposes of redesignation, because they will not have become due.
i. Section 172 Requirements
As provided in subpart 2, for ozone nonattainment areas such as the
Detroit area, the attainment planning requirements that would otherwise
apply under section 172(c), including the requirements under section
172(c)(1) and section 172(c)(2) for an attainment demonstration, RACM,
and RFP, are addressed by the specific requirements of section 182.\14\
---------------------------------------------------------------------------
\14\ See 42 U.S.C. 7511a.
---------------------------------------------------------------------------
Section 172(c)(3) requires submission and approval of a
comprehensive, accurate, and current inventory of actual emissions.
This requirement is superseded by the inventory requirement in section
182(a)(1) discussed below.
Section 172(c)(4) requires the identification and quantification of
allowable emissions for major new and modified stationary sources in an
area, and section 172(c)(5) requires source permits for the
construction and operation of new and modified major stationary sources
anywhere in the nonattainment area. The EPA approved Michigan's NSR
program on December 16, 2013 (78 FR 76064), and approved revisions on
May 12, 2021 (86 FR 25954). Most recently, the EPA approved Michigan's
certification that its SIP satisfies the nonattainment NSR requirements
of the CAA for the 2015 ozone NAAQS on June 9, 2023 (88 FR 37766).
Nonetheless, the EPA has determined that, since PSD requirements will
apply after redesignation, areas being redesignated need not comply
with the requirement that a NSR program be approved prior to
redesignation, provided that the area demonstrates maintenance of the
NAAQS without part D NSR.\15\ A more detailed rationale for this view
is described in the Nichols Memorandum.\16\ Michigan's PSD program will
become effective in the Detroit area upon redesignation to attainment.
The EPA conditionally approved Michigan's PSD program on September 16,
2008 (73 FR 53366), fully approved Michigan's PSD program on March 25,
2010 (75 FR 14352), and most recently approved revisions to Michigan's
PSD program on May 12, 2021 (86 FR 25954).
---------------------------------------------------------------------------
\15\ See rulemakings for Detroit, Michigan, 60 FR 12459, 12467
through 12468 (March 7, 1995); Cleveland-Akron-Lorain, Ohio, 61 FR
20458, 20469 through 20470 (May 7, 1996); Louisville, Kentucky, 66
FR 53665, 53669 (October 23, 2001); and Grand Rapids, Michigan, 61
FR 31831, 31834 through 31837 (June 21, 1996).
\16\ See the October 14, 1994, memorandum from Mary Nichols,
Assistant Administrator for Air and Radiation, entitled, ``Part D
New Source Review Requirements for Areas Requesting Redesignation to
Attainment.''
---------------------------------------------------------------------------
Section 172(c)(6) requires the SIP to contain control measures
necessary to provide for attainment of the NAAQS. Because attainment
has been reached, no additional measures are needed to provide for
attainment.
Section 172(c)(7) requires the SIP to meet the applicable
provisions of section 110(a)(2). As noted above, we believe the
Michigan SIP meets the requirements of section 110(a)(2) for purposes
of redesignation.
Section 172(c)(8) allows for equivalent modeling, emission
inventory, and planning procedures in certain circumstances upon
application
[[Page 47167]]
by the State, which is not applicable to this action.
CAA section 172(c)(9) requires the submission of contingency
measures. Because the area has attained, CAA section 172(c)(9)
requirements are no longer applicable as long as the area continues to
attain the standard.
ii. Section 176 Conformity Requirements
Section 176(c) of the CAA requires that federally supported or
funded projects conform to the applicable SIP. The requirement to
determine conformity applies to transportation plans, programs, and
projects that are developed, funded, or approved under title 23 of the
United States Code (U.S.C.) and the Federal Transit Act (transportation
conformity) as well as to all other federally supported or funded
projects (general conformity). State transportation conformity SIP
revisions must be consistent with Federal conformity regulations
relating to consultation, enforcement, and enforceability that the EPA
promulgated pursuant to its authority under the CAA.
The EPA interprets the conformity SIP requirements \17\ as not
applying for purposes of evaluating a redesignation request under
section 107(d) because State conformity rules are still required after
redesignation and Federal conformity rules apply where State conformity
rules have not been approved.\18\ Nonetheless, Michigan has an approved
conformity SIP for the Detroit area.\19\
---------------------------------------------------------------------------
\17\ CAA section 176(c)(4)(E) requires States to submit
revisions to their SIPs to reflect certain Federal criteria and
procedures for determining transportation conformity. Transportation
conformity SIPs are different from SIPs requiring the development of
motor vehicle emissions budgets, such as control strategy SIPs and
maintenance plans.
\18\ See Wall v. EPA, 265 F.3d 426 (6th Cir. 2001) (upholding
this interpretation); see also 60 FR 62748 (December 7, 1995)
(redesignation of Tampa, Florida).
\19\ See 61 FR 66609 (December 18, 1996) and 82 FR 17134 (April
10, 2017).
---------------------------------------------------------------------------
iii. CAA Section 182(a), Section 182(b), and Section 182(f)
Requirements
CAA section 182(a)(1) requires States to submit a comprehensive,
accurate, and current inventory of actual emissions from sources of
NOX and VOC emitted within the boundaries of the ozone
nonattainment area within two years of designation. The EPA approved
Michigan's base year emissions inventory for the Detroit area on July
6, 2022 (87 FR 40097).
Under CAA section 182(a)(2)(A), States with ozone nonattainment
areas that were designated prior to the enactment of the 1990 CAA
amendments were required to submit, within six months of
classification, all rules and corrections to existing VOC reasonably
available control technology (RACT) rules that were required under CAA
section 172(b)(3) prior to the 1990 CAA amendments. The Detroit area is
not subject to the CAA section 182(a)(2) RACT ``fix up'' requirement
for the 2015 ozone NAAQS because it was designated as nonattainment for
this standard after the enactment of the 1990 CAA amendments and, in
any case, Michigan complied with this requirement for the Detroit area
under the prior 1-hour ozone NAAQS.\20\
---------------------------------------------------------------------------
\20\ See 60 FR 46182 (September 7, 1994).
---------------------------------------------------------------------------
CAA section 182(a)(2)(B) requires each State with a Marginal ozone
nonattainment area that implemented or was required to implement a
vehicle I/M program prior to the 1990 CAA amendments to submit a SIP
revision for an I/M program no less stringent than that required prior
to the 1990 CAA amendments or already in the SIP at the time of the CAA
amendments, whichever is more stringent. For the purposes of the 2015
ozone NAAQS and the consideration of Michigan's redesignation request
for this standard, the Detroit area is not subject to the CAA section
182(a)(2)(B) requirement because the Detroit area was designated as
nonattainment for the 2015 ozone NAAQS after the enactment of the 1990
CAA amendments and because Michigan complied with this requirement for
the Detroit area under the prior 1-hour ozone NAAQS.
Regarding the source permitting and offset requirements of CAA
sections 182(a)(2)(C), 182(a)(4), and 182(b)(5), Michigan currently has
a fully approved part D NSR program in place. The EPA approved
Michigan's NSR program on December 16, 2013 (78 FR 76064), and most
recently approved revisions to Michigan's NSR program on May 12, 2021
(86 FR 25954). In addition, the EPA conditionally approved Michigan's
PSD program on September 16, 2008 (73 FR 53366), fully approved
Michigan's PSD program on March 25, 2010 (75 FR 14352), and most
recently approved revisions to Michigan's PSD program on May 12, 2021
(86 FR 25954). The State's PSD program will become effective in the
Detroit area upon redesignation to attainment.
CAA section 182(a)(3) requires States to submit periodic emission
inventories and a revision to the SIP to require the owners or
operators of stationary sources to annually submit emission statements
documenting actual VOC and NOX emissions. Michigan will
continue to update its emissions inventory at least once every three
years, consistent with the requirements of 40 CFR part 51, subpart A,
and in 40 CFR 51.122. The Consolidated Emissions Reporting Rule (CERR)
was promulgated by the EPA on June 10, 2002 (67 FR 39602). The CERR was
replaced by the Air Emissions Reporting Requirements on December 17,
2008 (73 FR 76539). The most recent triennial inventory for Michigan
was compiled for 2020, and 2023 is in progress. The EPA approved
Michigan's emission statement SIP for the Detroit area for the 2015
ozone NAAQS on July 6, 2022 (87 FR 40097).
CAA section 182(b) contains the requirements for areas classified
as Moderate. As discussed in section VI of this preamble, in this
action the EPA is proposing to adjust the deadline for Michigan to
submit Moderate SIP revisions for the Detroit area to no later than
December 5, 2026. Provided the EPA finalizes this SIP submittal
deadline adjustment and the redesignation of the Detroit area prior to
December 5, 2026, Moderate SIP requirements would not be considered
applicable requirements for purposes of redesignation because they will
not have become due and thus are not a prerequisite to redesignation.
CAA section 182(b)(1) requires the submission of an attainment
demonstration and RFP plan. Because the area has attained, CAA section
182(b)(1) requirements are no longer applicable as long as the area
continues to attain the standard.
CAA section 182(b)(2) requires States with Moderate nonattainment
areas to implement VOC RACT with respect to each of the following: (1)
all sources covered by a Control Technology Guideline (CTG) document
issued between November 15, 1990, and the date of attainment; (2) all
sources covered by a CTG issued prior to November 15, 1990; and (3) all
other major non-CTG stationary sources. However, as described in
section VI.B. of this preamble, the EPA is proposing to extend the
deadlines for SIP submissions associated with the Moderate
classification. Therefore, if finalized, CAA section 182(b)(2)
requirements would not be applicable for purposes of redesignation.
CAA section 182(b)(3) requires States to adopt Stage II gasoline
vapor recovery regulations. On May 16, 2012 (77 FR 28772), the EPA
determined that the use of onboard vapor recovery technology for
capturing gasoline vapor when gasoline-powered vehicles are refueled is
in widespread use throughout the highway motor vehicle fleet and waived
[[Page 47168]]
the requirement that current and former ozone nonattainment areas
implement Stage II vapor recovery systems on gasoline pumps.
CAA section 182(b)(4) requires a Basic vehicle I/M program in each
State with a Moderate ozone nonattainment area. However, as described
in section VI.B. of this preamble, the EPA is proposing to extend the
deadlines for SIP submissions associated with the Moderate
classification. Therefore, if finalized, section 182(b)(4) requirements
would not be applicable for purposes of redesignation.
CAA section 182(f) of the CAA establishes NOX
requirements for ozone nonattainment areas. CAA section 182(f)(1)
generally requires major sources of NOX to be covered by the
same levels of emission controls as required for major sources of VOC.
Since section 182(b)(2)(C) of the CAA requires areas classified as
Moderate (or above) to implement RACT for major VOC sources, these
ozone nonattainment areas are also required to implement NOX
RACT for major sources of NOX. However, as described in
section VI of this preamble, the EPA is proposing to extend the
deadlines for those submittals. Therefore, if finalized, CAA section
182(f) requirements would not be applicable for purposes of
redesignation.
Thus, as discussed above, the EPA finds that the Detroit area
satisfies all applicable requirements for purposes of redesignation
under section 110 and part D of the CAA.
2. The Detroit Area Has a Fully Approved SIP for Purposes of
Redesignation Under Section 110(k) of the CAA
At various times, Michigan has adopted and submitted, and the EPA
has approved, provisions addressing the various SIP elements applicable
for the ozone NAAQS. Providing the EPA finalizes the SIP submittal
deadline adjustment and the redesignation of the Detroit area prior to
December 5, 2026, the EPA will have fully approved the Michigan SIP for
the Detroit area under CAA section 110(k) for all requirements
applicable for purposes of redesignation under the 2015 ozone NAAQS.
The EPA may rely on prior SIP approvals in approving a redesignation
request.\21\ Additional measures may also be approved in conjunction
with a redesignation action.\22\
---------------------------------------------------------------------------
\21\ See the Calcagni Memorandum at page 3; Southwestern
Pennsylvania Growth Alliance v. Browner, 144 F.3d 984, 989-990 (6th
Cir. 1998); Wall v. EPA, 265 F.3d 426.
\22\ See 68 FR 25418, 25426 (May 12, 2003) and citations
therein.
---------------------------------------------------------------------------
C. Are the air quality improvements in the Detroit area due to
permanent and enforceable emission reductions?
To redesignate an area from nonattainment to attainment, CAA
section 107(d)(3)(E)(iii) requires the EPA to determine that the air
quality improvement in the area is due to permanent and enforceable
reductions in emissions resulting from the implementation of the SIP
and applicable Federal air pollution control regulations and other
permanent and enforceable emission reductions.
The EPA determined in the 2023 final redesignation that the
observed ozone air quality improvement in the Detroit area was due to
permanent and enforceable reductions in VOC and NOX
emissions resulting from State measures adopted into the SIP and
Federal measures. In making this determination, the EPA reviewed
analyses from EGLE's 2022 submittal. The State calculated the change in
emissions between 2014 and 2019. The reduction in emissions and the
corresponding improvement in air quality over this time period was
attributed to several regulatory control measures that the Detroit area
and upwind areas had implemented. In addition, Michigan provided an
analysis to demonstrate the improvement in air quality was not due to
unusually favorable meteorology. Michigan's analysis and the EPA's
discussion of the analysis are available in the docket for this
regulatory action (for example, in the 2022 submittal, the 2023
proposed redesignation, and the 2023 final redesignation).
The determination in the 2023 final redesignation is supported by
more recent air quality data, which show that the area has continued to
attain the standard, after accounting for wildfire impacts, for the
2021 through 2023, 2022 through 2024, and 2023 through 2025 periods.
This air quality data is additional evidence that the permanent and
enforceable emissions reductions documented in the 2022 submittal have
been sufficient to keep the Detroit area in attainment of the 2015
ozone NAAQS.
The EPA's determination under CAA section 107(d)(3)(E)(iii) was
challenged by petitioners but upheld by the Court in the 2025 Sixth
Circuit decision. The Court wrote that ``the EPA's determination that
the air-quality improvements in the Detroit area were due to permanent
and enforceable emission reductions was not arbitrary or capricious.''
For purposes of finalizing a future redesignation of the Detroit area,
the EPA proposes to continue to rely on the EPA's earlier
determination.
D. Does Michigan have a fully approvable ozone maintenance plan for the
Detroit area?
To redesignate an area from nonattainment to attainment, CAA
section 107(d)(3)(E)(iv) requires the EPA to determine that the area
has a fully approved maintenance plan pursuant to section 175A of the
CAA. Section 175A of the CAA sets forth the elements of a maintenance
plan for areas seeking redesignation from nonattainment to attainment.
Under CAA section 175A, the maintenance plan must demonstrate continued
attainment of the NAAQS for at least 10 years after the Administrator
approves a redesignation to attainment. Eight years after the
redesignation, the State must submit a revised maintenance plan which
demonstrates that attainment of the NAAQS will continue for an
additional 10 years beyond the initial 10-year maintenance period. To
address the possibility of future NAAQS violations, the maintenance
plan must contain contingency provisions, as the EPA deems necessary,
to assure prompt correction of the future NAAQS violation.
The Calcagni Memorandum provides further guidance on the content of
a maintenance plan, explaining that a maintenance plan should address
five elements: (1) an attainment emission inventory; (2) a maintenance
demonstration; (3) a commitment for continued air quality monitoring;
(4) a process for verification of continued attainment; and (5) a
contingency plan.
In conjunction with its request to redesignate the Detroit area to
attainment for the 2015 ozone NAAQS, EGLE's 2022 submittal included a
SIP revision to provide for maintenance of the 2015 ozone NAAQS through
2035. In the 2023 final redesignation, the EPA approved this
maintenance plan into the Michigan SIP, and determined that this
maintenance plan satisfied the requirement for redesignation to
attainment under CAA section 107(d)(3)(E)(iv) because it met the
requirements of CAA section 175A. Neither the EPA's approval of the
maintenance plan into the SIP nor the EPA's reliance on that
maintenance plan for purposes of redesignation were challenged by
petitioners, and EPA's actions related to the maintenance plan were not
vacated by the 2025 Sixth Circuit decision.
In its 2022 submittal, EGLE used 2019 to represent the attainment
year, and 2035 to represent the maintenance year. In its 2026
supplemental submittal, EGLE submitted revised versions of these
inventories, and EGLE is now
[[Page 47169]]
using the 2035 inventory to represent an interim year. In the 2026
supplemental submittal, EGLE submitted a new maintenance year inventory
for 2040, which is more than 10 years after the expected effective date
of a future redesignation to attainment.
As discussed below, the EPA proposes to find that Michigan's SIP-
approved maintenance plan, as updated by the 2026 supplemental
submittal, includes the necessary components under CAA section 175A and
CAA section 107(d)(3)(E)(iv). The EPA proposes to approve the updates
to the maintenance plan as a revision of the Michigan SIP.
1. Attainment Inventory
The EPA is proposing to determine that the Detroit area has
attained the 2015 ozone NAAQS based on monitoring data for the 2019-
2021 period. Michigan selected 2019 as the attainment emissions
inventory year, which is appropriate because it is one of the years in
the 2019-2021 period. The attainment emissions inventory identifies the
levels of VOC and NOX emissions in the Detroit area that are
sufficient to attain the 2015 ozone NAAQS. The emissions for the 2019
attainment year, by source category, are summarized in Table 2 and
Table 3 below.
Michigan provided inventories for point, nonpoint, onroad, and
nonroad sources. The point source category includes facilities that
report their emissions directly to EGLE, as well as sources such as
airports and rail yards. Nonpoint sources, sometimes called area
sources, include emissions from sources that are more ubiquitous, such
as consumer products or architectural coatings. Onroad sources are
vehicles that are primarily used on public roadways, such as cars,
trucks, and motorcycles. Nonroad sources include engine-based emissions
that do not occur on roads, such as trains or boats.
For the point, nonpoint, and nonroad source categories, in its 2026
supplemental submittal, EGLE made no changes to the emission levels
submitted in its 2022 submittal. EGLE's primary data source was the
EPA's 2016v2 modeling platform, which includes emissions data for the
years 2016, 2023, 2026 and 2032. To derive point, nonpoint, and nonroad
inventories for 2019, EGLE interpolated between 2016 and 2023 data from
the 2016v2 modeling platform. The 2016v2 modeling platform and 2014 NEI
have been quality-assured, and documentation regarding these datasets
and their methods is available on the EPA's website.\23\ Additional
information regarding point, nonpoint, and nonroad inventories is
available in the docket for this regulatory action (for example, in the
2022 submittal, the 2023 proposed redesignation, and the 2023 final
redesignation).
---------------------------------------------------------------------------
\23\ https://www.epa.gov/air-emissions-inventories/2014-national-emissions-inventory-nei-technical-support-document-tsd and
https://www.epa.gov/air-emissions-modeling/2016-version-2-technical-support-document.
---------------------------------------------------------------------------
For its onroad emissions inventory, Michigan submitted an analysis
by the Southeast Michigan Council of Governments (SEMCOG). In the 2022
submittal, this analysis used the EPA's MOVES3 model to generate July
weekday onroad emissions. In its 2026 supplemental submittal, EGLE
submitted updated inventories generated using the EPA's MOVES5 model,
the latest version of the EPA's MOVES model. SEMCOG's analysis relied
on local travel inputs including demographic data, travel demand
forecasting, road types, Vehicle Miles of Travel (VMT), Vehicle Hours
of Travel, vehicle population, and vehicle age, as well as
meteorological data. In attachment A of its 2026 supplemental
submittal, Michigan has included a detailed narrative of SEMCOG's
methods.
2. Has the State demonstrated maintenance of the ozone standard in the
Detroit area?
Michigan has demonstrated maintenance of the 2015 ozone NAAQS
through 2040 by projecting that current and future emissions of VOC and
NOX for the Detroit area remain at or below attainment year
emission levels. A maintenance demonstration need not be based on
modeling.\24\
---------------------------------------------------------------------------
\24\ See Wall v. EPA, 265 F.3d 426 (6th Cir. 2001), Sierra Club
v. EPA, 375 F. 3d 537 (7th Cir. 2004). See also 66 FR 53094, 53099
through 53100 (October 19, 2001), 68 FR 25418, 25430 through 25432
(May 12, 2003).
---------------------------------------------------------------------------
Michigan is using emissions inventories for the years 2035 and 2040
to demonstrate maintenance. 2040 was selected because it is more than
10 years after the expected effective date of the redesignation to
attainment, and 2035 was selected to demonstrate that emissions are not
expected to spike in the interim between the 2019 attainment year and
the 2040 final maintenance year.
To develop emissions inventories for the years 2035 and 2040,
Michigan used the same data sources discussed above in section IV.D.1.
of this proposed rule.
For its onroad emissions inventory, in the 2026 supplemental
submittal, Michigan again relied upon the SEMCOG analysis, which used
the EPA's MOVES5 model, the latest version of the EPA's MOVES model, to
generate July weekday onroad emissions for the 2019 attainment year, as
well as 2035 and 2040.
For the point, nonpoint, and nonroad source categories, for the
2035 year, in the 2026 supplemental submittal EGLE made no changes to
the emission levels from its 2022 submittal. For the 2040 year, EGLE
again used the EPA's 2016v2 modeling platform, and extrapolated forward
from the modeling platform data using the 2016 and 2032 years. To
convert annual emissions totals into a value of tons per ozone season
day, EGLE calculated a conversion factor for each county and each
source category. This conversion factor was generated from the 2016v2
modeling platform by taking the July category emissions and dividing
them by the annual category emissions. EGLE selected July as the
standard ozone season month after evaluating the summer months for
ozone season production.
By calculating its inventories through interpolation and
extrapolation, EGLE projects that changes within a source category and
county are linearly constant. For point sources, actual reductions may
not align with inventories derived from linear interpolation, because
shutdowns and the operation of new control equipment may be staggered
across several years. However, given the magnitude of the reductions in
other categories of sources, any uncertainty caused by linear
interpolation would be outweighed by the emissions reductions in other
sectors. Similarly, inventories derived from extrapolation may not
align with actual reductions for some types of sources. However, even
if Michigan as a cautious measure had projected that emissions from the
2016v2 modeling platform for the year 2032 would remain constant
through 2040, this level of emissions would still have been sufficient
to show that the area would maintain the standard through 2040.
Emissions data for the 2019 attainment year, 2035 interim year, and
2040 maintenance year are shown in Table 3 and Table 4 below. Data are
expressed in terms of tons per ozone season day.
[[Page 47170]]
Table 2--NOX Emissions in the Detroit Area for the 2019 Attainment Year, 2035 Interim Year, and 2040 Maintenance
Year
[Tons per ozone season day]
----------------------------------------------------------------------------------------------------------------
Net change
2019 2035 2040 (2019 through
2040)
----------------------------------------------------------------------------------------------------------------
Point........................................... 97.01 76.44 67.33 -29.68
Nonpoint........................................ 27.98 25.84 25.32 -2.66
Onroad.......................................... 112.60 25.60 17.80 -94.80
Nonroad......................................... 22.51 15.17 11.81 -10.70
---------------------------------------------------------------
Total....................................... 260.10 143.05 122.26 -137.84
----------------------------------------------------------------------------------------------------------------
Table 3--VOC Emissions in the Detroit Area for the 2019 Attainment Year, 2035 Interim Year, and 2040 maintenance
year
[Tons per ozone season day]
----------------------------------------------------------------------------------------------------------------
Net change
2019 2035 2040 (2019 through
2040)
----------------------------------------------------------------------------------------------------------------
Point........................................... 13.74 14.12 14.36 +0.62
Nonpoint........................................ 134.77 133.11 132.60 -2.17
Onroad.......................................... 55.40 27.90 22.50 -32.90
Nonroad......................................... 30.46 26.56 24.91 -5.55
---------------------------------------------------------------
Total....................................... 234.37 201.69 194.37 -40.00
----------------------------------------------------------------------------------------------------------------
As shown in Table 2 and Table 3, NOX and VOC emissions
in the Detroit area are projected to decrease by 137.84 tons per ozone
season day and 40.00 tons per ozone season day, respectively, between
the 2019 attainment year and 2040 maintenance year. Michigan's
maintenance demonstration for the Detroit area shows maintenance of the
2015 ozone NAAQS by providing emissions information to support the
demonstration that future emissions of NOX and VOC will
remain at or below 2019 emission levels when considering future source
growth.
On February 12, 2026, the EPA finalized the rescission of the GHG
Endangerment Finding and repealed all greenhouse gas (GHG) emission
standards for light-duty, medium-duty, and heavy-duty vehicles and
engines (``Endangerment Finding Rescission Rule'').\25\ Due to this
action, aspects of the State's planning assumptions from the EPA's
Motor Vehicle Emission Simulator model versions 5 (MOVES5) are no
longer entirely consistent with the latest information. The EPA
recognizes that States have relied on MOVES4 and MOVES5, including the
national default electric vehicle (EV) projections tied in part to the
implementation of these now-repealed standards, in developing some SIP
actions that have been submitted to the EPA.
---------------------------------------------------------------------------
\25\ See Rescission of the Greenhouse Gas Endangerment Finding
and Motor Vehicle Greenhouse Gas Emission Standards Under the Clean
Air Act, 91 FR 7686, February 18, 2026.
---------------------------------------------------------------------------
The Detroit maintenance plan was developed using MOVES5 and the
latest EPA guidance on the use of MOVES in SIP development that was
available at the time. Per the EPA's MOVES Policy Guidance, States
``should use the latest version of MOVES that is available at the time
that a SIP is developed.'' \26\ In this guidance, the EPA also stated
that an earlier version of MOVES can be used in SIP development if
significant work has already been completed on a SIP using that earlier
version.\27\ Therefore, the State developed this SIP based on an
emissions model that the EPA expected States to use. In addition, the
EPA indicated that for fuel type distributions for onroad vehicles that
include estimates of EVs, States should use local data if available and
could rely on the default information within the model as planning
assumptions.\28\ Therefore, based on EPA's statements in the EPA's
MOVES Policy and Technical Guidance, the State reasonably relied on the
assumptions in MOVES5.
---------------------------------------------------------------------------
\26\ See Section 2.1 (page 10) of ``MOVES5 Policy Guidance: Use
of MOVES for State Implementation Plan Development, Transportation
Conformity, General Conformity, and Other Purposes'' (EPA-420-B-24-
038, November 2024).
\27\ Id.
\28\ See Section 4.8.3 (page 56) of ``MOVES5 Technical Guidance:
Using MOVES to Prepare Emission Inventories for State Implementation
Plans and Transportation Conformity'' (EPA-420-B-24-043, November
2024).
---------------------------------------------------------------------------
As a general principle, the SIP is an iterative document, subject
to various revisions over time. This is because the SIP revision
process is cyclical by nature per the different obligations under the
CAA. The EPA acknowledges the significant amount of time and resources
required by States to develop a SIP revision. In the evaluation of this
SIP submittal, the EPA is considering the modeling and information
provided by Michigan and affirming that Michigan relied on the latest
EPA model and guidance information available at the time it developed
the SIP. To acknowledge and accommodate reliance interests States may
have had in MOVES5 based on the EPA's statements in the EPA's MOVES
Policy and Technical Guidance, and to treat all States consistently
that submitted SIPs prior to or shortly after the Endangerment Finding
Rescission Rule where significant work had been completed, the EPA is
proposing to find that Michigan appropriately estimated onroad mobile
source emissions for this SIP based on MOVES5.
3. Continued Air Quality Monitoring, Verification of Continued
Attainment, and Contingency Plan
With respect to the requirements for a commitment for continued air
quality monitoring, a process for verification of continued attainment,
and contingency plan, information regarding Michigan's maintenance plan
is available in the
[[Page 47171]]
docket for this regulatory action (for example, in the 2022 submittal,
the 2023 proposed redesignation, and the 2023 final redesignation). In
its 2026 supplemental submittal, EGLE made no changes to these aspects
of Michigan's SIP-approved maintenance plan. On May 19, 2023 (88 FR
32594), the EPA determined these components of the maintenance plan
meet the requirements at CAA section 175A and we propose to confirm
that finding.
The EPA has determined that Michigan's maintenance plan adequately
addresses the five basic components of a maintenance plan: attainment
inventory, maintenance demonstration, monitoring network, verification
of continued attainment, and a contingency plan. In addition, as
required by section 175A(b) of the CAA, Michigan has committed to
submit to the EPA an updated ozone maintenance plan eight years after
redesignation of the Detroit area to cover an additional ten years
beyond the initial 10-year maintenance period. Thus, the EPA finds that
the maintenance plan for the Detroit area, as updated by the 2026
supplemental submittal, meets the requirements of section 175A of the
CAA. The EPA proposes to approve the updates to the maintenance plan as
a revision to the Michigan SIP.
V. Has the State adopted approvable motor vehicle emission budgets?
A. Motor Vehicle Emission Budgets
Under section 176(c) of the CAA, new transportation plans,
programs, or projects that receive Federal funding or support, such as
the construction of new highways, must ``conform'' to (i.e., be
consistent with) the SIP. Conformity to the SIP means that
transportation activities will not cause or contribute to any new air
quality violations, increase the frequency or severity of any existing
air quality problems, or delay timely attainment or any required
interim emissions reductions or any other milestones. Regulations at 40
CFR part 93 set forth EPA policy, criteria, and procedures for
demonstrating and ensuring conformity of transportation activities to a
SIP. Transportation conformity is a requirement for nonattainment and
maintenance areas. Maintenance areas are areas that were previously
nonattainment for a particular NAAQS, but that have been redesignated
to attainment with an approved CAA section 175A maintenance plan for
the NAAQS.
Under the CAA, States are required to submit, at various times,
control strategy SIPs for nonattainment areas and maintenance plans for
areas seeking redesignations to attainment of the ozone standard and
maintenance areas.\29\ These control strategy SIPs (including RFP plans
and attainment plans) and maintenance plans must include motor vehicle
emissions budgets for criteria pollutants and/or their precursor
pollutants to address pollution from onroad transportation sources. In
ozone areas, budgets are established for the precursor pollutants VOC
and NOX, per 40 CFR 93.102(b)(2)(i). The budgets are the
portion of the total allowable emissions that are allocated to highway
and transit vehicle use that, together with emissions from other
sources in the area, will provide for attainment or maintenance.\30\
The budget serves as a ceiling on emissions from an area's planned
transportation system.
---------------------------------------------------------------------------
\29\ See the SIP requirements for the 2015 ozone standard in the
EPA's December 6, 2018 (83 FR 62998), implementation rule.
\30\ See 40 CFR 93.101 for the definition of ``motor vehicle
emissions budget.''
---------------------------------------------------------------------------
Under 40 CFR part 93, a budget for an area seeking redesignation to
attainment must be established, at minimum, for the last year of the
maintenance plan.\31\ A State may adopt budgets for other years as
well. The preamble also describes how to establish the budget(s) in the
SIP and how to revise the budget(s), if needed, after initially
establishing a budget in the SIP.
---------------------------------------------------------------------------
\31\ See 40 CFR 93.118(b)(2).
---------------------------------------------------------------------------
As discussed earlier, Michigan's maintenance plan includes
NOX and VOC budgets for the Detroit area for 2035, which is
an interim year, as well as 2040, which is the last year of the
maintenance period. Establishing budgets for 2035 allows the area to
use them for transportation conformity determinations instead of making
the qualitative finding described in 40 CFR 93.118(b)(2)(i). The EPA
has reviewed Michigan's NOX and VOC budgets for the area
and, in this action, is proposing to approve them.
We are also starting the adequacy review process for these budgets
to determine if they meet the adequacy criteria in the transportation
conformity regulations (40 CFR 93.118(e)(4)).\32\ Michigan's updated
maintenance plan from its 2026 supplemental submittal, including the
budgets for this area, is available for public comment via this
proposed rulemaking. After the public comment period, the EPA can make
a finding of adequacy for the budgets.
---------------------------------------------------------------------------
\32\ See 40 CFR 93.118(f)(2) for requirements associated with
making adequacy findings through rulemaking on a submitted SIP.
---------------------------------------------------------------------------
The EPA notes that Michigan's submission meets the adequacy
criteria at 40 CFR 93.118(e)(4): The submission was endorsed by the
Governor's designee and Michigan provided opportunity for a public
hearing. The budgets were developed as part of an interagency
consultation process which includes Federal, State, and local agencies.
The budgets were clearly identified and precisely quantified. These
budgets, when considered together with all other emissions sources, are
consistent with maintenance of the 2015 ozone NAAQS. These criteria
also support the EPA's proposed approval of the budgets as part of the
approval of the maintenance plan.
Table 4--Motor Vehicle Emissions Budgets for the Detroit Area for the 2035 Interim Year and 2040 Maintenance Year
[Tons per ozone season day]
--------------------------------------------------------------------------------------------------------------------------------------------------------
2035 Interim year 2040 Maintenance year
-----------------------------------------------------------------------------------------------
Projected Projected
onroad Safety margin Total budget onroad Safety margin Total budget
emissions allocation emissions allocation
--------------------------------------------------------------------------------------------------------------------------------------------------------
NOX..................................................... 25.60 76.08 101.68 17.80 82.71 100.51
VOCs.................................................... 27.90 21.24 49.14 22.50 24.00 46.50
--------------------------------------------------------------------------------------------------------------------------------------------------------
As shown in Table 4, the 2035 and 2040 budgets are larger than the
estimated 2035 and 2040 onroad sector emissions. To accommodate future
variations in VMT in the area, EGLE allocated to the mobile sector a
portion
[[Page 47172]]
of the safety margin, as described further below.\33\ Michigan has
demonstrated that the Detroit area can maintain the 2015 ozone NAAQS in
the 2040 maintenance year with mobile source emissions of 100.51 tons
per ozone season day of NOX and 46.50 tons per ozone season
day of VOCs. Similarly, the Detroit area can maintain the 2015 ozone
NAAQS in the 2035 interim year with mobile source emissions of 101.68
tons per ozone season day of NOX and 49.14 tons per ozone
season day of VOCs. Despite partial allocation of the safety margin,
emissions will remain under emission levels in the 2019 attainment
year.
---------------------------------------------------------------------------
\33\ Allocation of a safety margin to an area's motor vehicle
emissions budgets is provided for by the transportation conformity
rule. See 40 CFR 93.124(a).
---------------------------------------------------------------------------
The EPA is proposing to approve the budgets for use to determine
transportation conformity in the Detroit area, because the EPA has
determined that the area can maintain attainment of the 2015 ozone
NAAQS for the relevant maintenance period with mobile source emissions
at the levels of the budgets.
B. What is a safety margin?
A ``safety margin'' is the amount by which the total projected
emissions from all sources of a given pollutant are less than the total
emissions that would satisfy the applicable requirement for
maintenance. 40 CFR 93.101. As noted in Table 2 and Table 3, the
emissions in the Detroit area are projected to have safety margins of
137.84 tons per ozone season day for NOX and 40.00 tons per
ozone season day for VOC in 2040 (the difference between emissions in
the 2019 attainment year, and projected emissions in the 2040
maintenance year, for all sources in the Detroit area). Similarly,
there is a safety margin of 117.05 tons per ozone season day for
NOX and 32.68 tons per ozone season day for VOC in 2035.
Even if the full amount of the safety margin were added to the
projected onroad mobile source levels, these counties would still
demonstrate maintenance since emissions levels would equal those in the
attainment year.
As shown in Table 4 above, Michigan is allocating a portion of that
safety margin to the mobile source sector. Specifically, in 2035,
Michigan is allocating 76.08 of the 117.5 tons per ozone season day
NOX safety margin available to the NOX budget,
and 21.24 tons of the 32.68 tons per ozone season day VOC safety margin
available to the VOC budget. In 2040, Michigan is allocating 82.71 of
the 137.84 tons per ozone season day NOX safety margin
available to the NOX budget, and 24.00 tons of the 40.00 ton
per ozone season day VOC safety margin available to the VOC budget.
Michigan is requesting that only a portion of the available safety
margins be allocated to the budgets. Therefore, even though the State
has submitted budgets that are larger than the projected onroad mobile
source emissions for 2035 and 2040 contained in the demonstration of
maintenance, the increase in onroad mobile source emissions that can be
considered for transportation conformity purposes is within the safety
margins of the ozone maintenance demonstration. Further, once the
budgets are found adequate, these portions of the safety margins that
are allocated to onroad mobile sources will not be available for use by
other sources.
VI. Adjustment of Certain SIP Submittal and Implementation Deadlines
A. Sixth Circuit Court of Appeals Decision in Sierra Club v. EPA
As discussed in section III of this preamble, section 107(d)(3)(E)
of the CAA contains the criteria for redesignation. CAA section
107(d)(3)(E)(v) specifically requires that ``the State containing such
area has met all requirements applicable to the area under section
[110] of this title and part D of this subchapter.'' The EPA's
interpretation of that provision since passage of the 1990 CAA
Amendments has been that requirements with submission deadlines
occurring after the State's submission of its redesignation request are
not ``applicable'' under CAA section 107(d)(3)(E)(v) for purposes of
evaluating the approvability of the redesignation.
In the 2023 final redesignation of the Detroit area, the EPA relied
on its longstanding interpretation of CAA section 107(d)(3)(E)(v) in
finding that Michigan had satisfied that requirement, because the State
had met all applicable requirements that were due as of the time of the
State's submission requesting redesignation. The EPA's redesignation of
the Detroit ozone nonattainment area was challenged, partially based on
the argument that the CAA required Michigan to have met all applicable
requirements due as of the time the EPA issued the final redesignation,
rather than the requirements due as of the time Michigan submitted its
redesignation application.
On December 5, 2025, the Sixth Circuit Court of Appeals vacated the
EPA's redesignation of the Detroit area. In the 2025 Sixth Circuit
decision, the Court held that Michigan was required to have met all
requirements due at the time of the EPA's redesignation action, not
just the requirements that had been due as of the time of submittal of
the redesignation request.
B. Proposed Adjustment of Certain SIP Submittal and Implementation
Deadlines Associated With the Moderate Classification
As noted, the EPA's interpretation of CAA section 107(d)(3)(E)(v)
has informed State and Federal implementation of redesignations for
more than three decades. Michigan devoted considerable resources
towards preparing its request to redesignate the Detroit nonattainment
area to attainment. And, understandably, it had done so under the
longstanding pre-Sierra Club framework that had governed redesignations
and the expectations of what States were required to submit in order
for areas to have their redesignation requests granted. Therefore, the
2022 submittal did not address Moderate area SIP requirements, because
the EPA had not yet proposed or finalized a reclassification of the
Detroit area to Moderate nonattainment, nor had the EPA set any
deadline for Moderate requirements.
The final determination that the area failed to attain, issued
February 1, 2023 (88 FR 6633), reclassified the Detroit area to
Moderate nonattainment and established a SIP due date of March 1, 2023.
The area was then redesignated to attainment on May 19, 2023 (88 FR
32594), terminating any obligation for the Detroit area to submit
Moderate area requirements. The Court's vacatur of the redesignation in
its December 5, 2025, decision had the effect of restoring the area's
designation and classification to Moderate nonattainment. However,
during the intervening years while the redesignation has been
effective, Michigan has understandably believed itself not to be
subject to the requirement to submit the Moderate elements.
The EPA is therefore taking these circumstances into account in
proposing to adjust the deadline for certain Moderate area SIP
requirements for the Detroit area. The Agency has previously made
similar adjustments to implementation deadlines in response to an
adverse court decision.\34\ In that instance, the EPA had for many
years implemented particulate matter standards under subpart 1 of the
CAA. The D.C. Circuit held that the Agency had erred in doing so, and
that the CAA required the implementation of those
[[Page 47173]]
standards to be governed by subpart 4 instead. In response to that
adverse decision, rather than find that States were immediately in
default of subpart 4 obligations, the EPA established prospective,
relatively expedited deadlines for States to comply with any
outstanding subpart 4 requirements.\35\ The D.C. Circuit found that the
Agency acted within its authority in establishing new deadlines ``in
the novel circumstances of this case, [where] all affected parties have
been long acting on the mistaken assumption that a different framework
. . . controls.'' \36\
---------------------------------------------------------------------------
\34\ See 79 FR 31566 (June 2, 2014).
\35\ See 78 FR 69806, 69809 through 69810 (November 21, 2013)
(proposing a SIP submission deadline of December 31, 2014 on the
basis that it ``provides a relatively brief but reasonable amount of
time for States to ascertain whether and to what extent any
additional submissions are needed for a [particulate matter]
nonattainment area, and to develop, adopt and submit any such
SIPs'').
\36\ See Wildearth Guardians v. EPA, 830 F.3d 529, 539 (D.C.
Cir. 2016).
---------------------------------------------------------------------------
In establishing new deadlines in the fine particulate matter
(PM2.5) rule at issue in Wildearth Guardians, the EPA relied
upon its general rulemaking authority under CAA section 301(a), which
authorizes the Administrator to promulgate such regulations as are
necessary to carry out his functions under the CAA. The Court held that
the rule represented ``a reasonable exercise of the EPA's gap-filling
authority'' in that it retained the CAA's attainment deadline for the
areas, ``even though that date was fast approaching by the time of the
Rule's promulgation,'' and ``[m]oreover, the agency's plan submission
deadline . . . was less than two years after the NRDC decision
[requiring implementation of the PM2.5 NAAQS under subpart
4] and some six months after the [final publication of] the Rule.'' Id.
at 541. The Court noted that the ``short timeframe suggests a
reasonable effort to expedite compliance with the Subpart 4 framework
without imposing unfair obligations on states.'' Id.
Here, the EPA is proposing to alter deadlines for reasons similar
to the EPA's action establishing new deadlines for PM2.5
SIPs. Additionally, the EPA has specific authority over reclassified
ozone nonattainment areas under CAA section 182(i) to ``adjust any
applicable deadlines (other than attainment dates) to the extent such
adjustment is necessary or appropriate to assure consistency among the
required submissions.'' For reclassified areas, SIP submission and
control measure implementation deadlines are established by rule at 40
CFR 51.1402(b)(1)(i).\37\ As noted in that regulatory provision, the
default deadline for reclassified areas applies ``unless the
Administrator establishes a different deadline in a separate action.''
---------------------------------------------------------------------------
\37\ 40 CFR 51.1402(b)(1)(i) establishes the SIP revision
deadline for reclassified areas as 18 months after the effective
date of the relevant reclassification or January 1 of the attainment
year, whichever is earlier.
---------------------------------------------------------------------------
The EPA is therefore proposing under its statutory and regulatory
authority to establish a different Moderate SIP submission and control
measure implementation deadline for the Detroit area. This one-time
adjustment of the Moderate area SIP submission and implementation
deadline for the reclassified Detroit ozone nonattainment area) is
necessary and appropriate because without such adjustment, Michigan
would immediately be in default of its obligation to submit and
implement certain Moderate elements for the Detroit area, despite its
reasonable assumption since May 2023 that it had no obligation to do so
as a result of the area's redesignation to attainment. This proposed
adjustment will allow the State to make any submissions it determines
necessary. The EPA proposes to adjust the deadline for Michigan to
submit SIP revisions for the Detroit area for requirements associated
with the Moderate classification, such as RACM/RACT and Basic I/M, to
no later than December 5, 2026, one year after the 2025 Sixth Circuit
decision. Except for Basic I/M, the EPA proposes that the
implementation deadline for these requirements should also be adjusted
to no later than December 5, 2026.
VII. Adjustment of Basic I/M Implementation Deadline
In the 2022 proposed reclassification, the EPA noted that ``given
the unique nature of I/M programs, there are many challenges, tasks,
and milestones that must be met in establishing and implementing an I/M
program.'' For States that did not intend to rely upon emission
reductions from their Basic I/M program in attainment or RFP SIPs, the
EPA proposed to allow Basic I/M programs to be fully implemented no
later than 4 years after the effective date of reclassification. In the
2023 final reclassification, the EPA finalized this implementation
deadline of no later than 4 years after the effective date of
reclassification, should EGLE not intend to rely upon emission
reductions from their I/M program in attainment or RFP SIPs.
Similarly, on January 17, 2025 (90 FR 5651), in a final rule titled
State Implementation Plan Submittal Deadlines and Implementation
Requirements for Reclassified Nonattainment Areas Under the Ozone
National Ambient Air Quality Standards, the EPA established default SIP
submittal and control measure implementation deadline requirements for
reclassified ozone nonattainment areas. For I/M, that rule required
implementation as expeditiously as practicable, but no later than 4
years after the effective date of the relevant reclassification, unless
the I/M program is needed for attainment by the attainment date or RFP,
in which case the State shall provide for full implementation of such
I/M program no later than the beginning of the attainment year ozone
season.\38\
---------------------------------------------------------------------------
\38\ See 40 CFR 51.1402(b)(2)(ii).
---------------------------------------------------------------------------
In the 2023 final clean data determination, the EPA suspended the
requirement for attainment or RFP SIPs, meaning the EPA does not expect
EGLE to rely upon emission reductions from their I/M program for
purposes of any other requirement.
Considering the numerous challenges and milestones necessary in
implementing a Basic I/M program, the EPA believes it is reasonable to
set an implementation deadline that is 4 years from December 5, 2026.
Therefore, the EPA is proposing under CAA section 182(i) to adjust the
deadline for Michigan to implement I/M for the Detroit area to no later
than December 5, 2030.
VIII. What action is the EPA taking?
The EPA is proposing to determine that the Detroit area has met the
requirements for redesignation under section 107(d)(3)(E) of the CAA,
and the EPA is thus proposing to change the legal designation of the
Detroit area from nonattainment to attainment for the 2015 ozone NAAQS
in accordance with EGLE's 2022 submittal and 2026 supplemental
submittal. The EPA is also proposing to approve, as a revision to the
Michigan SIP, the State's updated maintenance plan for the area, which
is designed to keep the Detroit area in attainment of the 2015 ozone
NAAQS through 2040. As part of the maintenance plan, the EPA is
initiating the adequacy process and proposing to approve the newly
established 2035 and 2040 motor vehicle emissions budgets for the
Detroit area. Additionally, the EPA is proposing to adjust the deadline
for Michigan to submit SIP revisions for the Detroit area for
requirements associated with the Moderate classification, as well as
the deadline to implement these measures except for Basic I/M, to no
later than December 5, 2026. The EPA is proposing to adjust the
deadline for Michigan to implement
[[Page 47174]]
Basic I/M in the Detroit area to no later than December 5, 2030. The
EPA also proposes to take final agency action on an exceptional events
request submitted by EGLE on April 15, 2026, and concurred on by the
EPA on June 4, 2026.
IX. Statutory and Executive Order Reviews
Under the CAA, redesignation of an area to attainment and the
accompanying approval of a maintenance plan under section 107(d)(3)(E)
are actions that affect the status of a geographical area and do not
impose any additional regulatory requirements on sources beyond those
imposed by State law. A redesignation to attainment does not in and of
itself create any new requirements, but rather results in the
applicability of requirements contained in the CAA for areas that have
been redesignated to attainment. Moreover, 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, the proposed actions to approve Michigan's SIP submissions
merely approve State law as meeting Federal requirements and do not
impose additional requirements beyond those imposed by State law. For
these reasons, this action:
Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993);
Is not an Executive Order 14192 (90 FR 9065, February 6,
2025) regulatory action because this action is not significant under
Executive Order 12866;
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 subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a State program;
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 rulemaking 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).
List of Subjects
40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Ozone,
Reporting and recordkeeping requirements, Volatile organic compounds.
40 CFR Part 81
Environmental protection, Air pollution control, National parks,
Wilderness areas.
Dated: July 13, 2026.
Anne Vogel,
Regional Administrator, Region 5.
[FR Doc. 2026-15168 Filed 7-27-26; 8:45 am]
BILLING CODE 6560-50-P