Proposed Rule2025-20497
Finding of Failure To Attain and Reclassification of Tribal Portions of the Greater Connecticut Ozone Nonattainment Area as Serious for the 2015 Ozone National Ambient Air Quality Standards
Primary source
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Published
November 20, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) previously granted the State of Connecticut's request to reclassify the Greater Connecticut ozone nonattainment area from Moderate to Serious under the 2015 ozone National Ambient Air Quality Standards (NAAQS). That request, however, did not include areas governed by the Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe that are located within this nonattainment area. Given that ozone monitoring data indicate that the Greater Connecticut area failed to attain the 2015 ozone NAAQS by the applicable attainment date, we are proposing to find that these tribal portions of the area did not attain the standards by the attainment date and to reclassify those portions of the area by operation of law to Serious nonattainment for the 2015 ozone NAAQS. This action, if finalized as proposed, would fulfill the EPA's statutory obligation to determine whether the Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe portions of the Greater Connecticut area attained the NAAQS by the attainment date. This action also solicits public comment on EPA's prior action on CT DEEP's request to exclude event-influenced air quality monitoring data from regulatory decisions. EPA is required to provide an opportunity for public comment on the claimed exceptional events and all supporting data. This proposed action provides the public with an opportunity to comment on the claimed exceptional events, all supporting documents, and the EPA's July 22, 2024 concurrence and nonconcurrence with CT DEEP's request.
Full Text
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<title>Federal Register, Volume 90 Issue 222 (Thursday, November 20, 2025)</title>
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[Federal Register Volume 90, Number 222 (Thursday, November 20, 2025)]
[Proposed Rules]
[Pages 52297-52303]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-20497]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R01-OAR-2024-0325; FRL-13014-01-R1]
Finding of Failure To Attain and Reclassification of Tribal
Portions of the Greater Connecticut Ozone Nonattainment Area as Serious
for the 2015 Ozone National Ambient Air Quality Standards
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) previously granted
the
[[Page 52298]]
State of Connecticut's request to reclassify the Greater Connecticut
ozone nonattainment area from Moderate to Serious under the 2015 ozone
National Ambient Air Quality Standards (NAAQS). That request, however,
did not include areas governed by the Mashantucket Pequot Tribal Nation
and the Mohegan Indian Tribe that are located within this nonattainment
area. Given that ozone monitoring data indicate that the Greater
Connecticut area failed to attain the 2015 ozone NAAQS by the
applicable attainment date, we are proposing to find that these tribal
portions of the area did not attain the standards by the attainment
date and to reclassify those portions of the area by operation of law
to Serious nonattainment for the 2015 ozone NAAQS. This action, if
finalized as proposed, would fulfill the EPA's statutory obligation to
determine whether the Mashantucket Pequot Tribal Nation and the Mohegan
Indian Tribe portions of the Greater Connecticut area attained the
NAAQS by the attainment date. This action also solicits public comment
on EPA's prior action on CT DEEP's request to exclude event-influenced
air quality monitoring data from regulatory decisions. EPA is required
to provide an opportunity for public comment on the claimed exceptional
events and all supporting data. This proposed action provides the
public with an opportunity to comment on the claimed exceptional
events, all supporting documents, and the EPA's July 22, 2024
concurrence and nonconcurrence with CT DEEP's request.
DATES: Written comments must be received on or before December 22,
2025.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R01-
OAR-2024-0325 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>, or via email to
<a href="/cdn-cgi/l/email-protection#aec2c7c2c2c7dd80decfdadcc7cdc5eecbdecf80c9c1d8"><span class="__cf_email__" data-cfemail="f4989d98989d87da849580869d979fb4918495da939b82">[email protected]</span></a>. For comments submitted at <a href="http://Regulations.gov">Regulations.gov</a>,
follow the online instructions for submitting comments. Once submitted,
comments cannot be edited or removed from <a href="http://Regulations.gov">Regulations.gov</a>. For either
manner of submission, the EPA may publish any comment received to its
public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. 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 or multimedia
submissions, and general guidance on making effective comments, please
visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>. Publicly
available docket materials are available at <a href="https://www.regulations.gov">https://www.regulations.gov</a>
or at the U.S. Environmental Protection Agency, EPA Region 1 Regional
Office, Air and Radiation Division, 5 Post Office Square--Suite 100,
Boston, MA. EPA requests that if at all possible, you contact the
contact listed in the FOR FURTHER INFORMATION CONTACT section to
schedule your inspection.
FOR FURTHER INFORMATION CONTACT: Patrick Lillis, Air and Radiation
Division (Mail Code 5-MI), U.S. Environmental Protection Agency, Region
1 5 Post Office Square, Suite 100, Boston, Massachusetts 02109-3912;
tel. (617)-918-1067, or by email at <a href="/cdn-cgi/l/email-protection#721e1b1e1e1b015c021306001b1119321702135c151d04"><span class="__cf_email__" data-cfemail="3955505555504a1749584d4b505a52795c4958175e564f">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean EPA.
Table of Contents
I. Background and Purpose
A. Ozone Reclassification
1. What is the background for the proposed action?
2. Overview of Proposal
3. What is the statutory authority for the proposed actions?
4. How does EPA determine whether an area has attained the 2015
ozone standard?
B. Exceptional Events
1. What is the background for the proposed action?
2. Overview of Proposal
II. What is the EPA proposing and what is the rationale?
A. Evaluation of Design Value Data and Exceptional Events
Documentation
B. Determination of Failure To Attain and Reclassification
C. Serious Area Requirements and Proposed Schedule
III. Proposed Action
IV. Statutory and Executive Order Reviews
I. Background and Purpose
A. Ozone Reclassification
1. What is the background for the proposed action?
The CAA requires the EPA to establish primary and secondary NAAQS
for certain pervasive pollutants that ``may reasonably be anticipated
to endanger public health and welfare.'' The primary NAAQS is designed
to protect public health with an adequate margin of safety, and the
secondary NAAQS is designed to protect public welfare and the
environment. The EPA has set NAAQS for six common air pollutants,
referred to as criteria pollutants, including ozone. The NAAQS
represent the air quality levels an area must meet to comply with the
CAA. Ozone is a gas composed of three oxygen atoms and is created by
chemical reactions between volatile organic compounds (VOC) and oxides
of nitrogen (NO<INF>X</INF>) in the atmosphere in the presence of
sunlight. Ground-level ozone can harm human health and the environment.
Ozone exposure has been associated with increases in susceptibility to
respiratory infections, medication use by asthmatics, doctor visits,
and emergency department visits and hospital admissions for individuals
with respiratory disease. Ozone exposure may also contribute to
premature death, especially in people with heart and lung disease.
In October 2015, the EPA strengthened the primary and secondary
eight-hour ozone NAAQS from 0.075 parts per million (ppm) to 0.070 ppm
(``2015 ozone NAAQS'').\1\ In accordance with section 107(d) of the
CAA, the EPA must designate an area ``nonattainment'' if it is
violating the NAAQS or if it is contributing to a violation of the
NAAQS in a nearby area. With respect to the ozone NAAQS, the EPA
further classifies nonattainment areas as ``Marginal,'' ``Moderate,''
``Serious,'' ``Severe,'' or ``Extreme,'' depending upon the ozone
design value for an area.\2\ As a general matter, higher classified
ozone nonattainment areas are subject to additional CAA planning
requirements than lower classified areas but are allowed more time to
demonstrate attainment of the ozone NAAQS.\3\
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\1\ 80 FR 65291, October 26, 2015.
\2\ See CAA section 181(a)(1). For the 2015 ozone NAAQS, the
design value at each monitoring site is the annual fourth-highest
daily maximum 8-hour average ozone concentration, averaged over
three years. The design value for an area is the highest design
value among the monitoring sites in the area.
\3\ See, generally, subpart 2 of part D of title I of the CAA.
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Effective on August 3, 2018, the EPA designated 52 areas throughout
the country as nonattainment for the 2015 ozone NAAQS.\4\ In a separate
action, the EPA assigned classification thresholds and attainment dates
based on the severity of an area's ozone problem, determined by the
area's design value
[[Page 52299]]
(DV).<SUP>5 6</SUP> The EPA established the attainment date for
Marginal, Moderate, and Serious nonattainment areas as 3 years, 6
years, and 9 years, respectively, from the effective date of the final
designations. Thus, the attainment date for Marginal nonattainment
areas for the 2015 ozone NAAQS was August 3, 2021, the attainment date
for Moderate areas was August 3, 2024, and the attainment date for
Serious areas is August 3, 2027. On October 7, 2022, the EPA determined
that 22 areas including the Greater Connecticut area, did not attain
the standards by the Marginal attainment date,\7\ and these areas were
reclassified as Moderate by operation of law. The Mashantucket Pequot
Tribal Nation and the Mohegan Indian Tribe, which are the two tribal
territories being addressed in this proposed action, are located within
the boundaries of the Greater Connecticut nonattainment area.
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\4\ 83 FR 25776, June 4, 2018.
\5\ 83 FR 10376, May 8, 2018.
\6\ CAA section 181(b)(2)(A). A DV is a statistic used to
compare data collected at an ambient air quality monitoring site to
the applicable NAAQS to determine compliance with the standard. The
data handling conventions for calculating DVs for the 2015 ozone
NAAQS are specified in appendix U to 40 CFR part 50. See also n.3,
supra.
\7\ 87 FR 60897, November 7, 2022
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2. Overview of Proposal
The EPA is required to determine whether areas designated
nonattainment for an ozone NAAQS attained the standard by the
applicable attainment date, and to take certain steps for areas that
failed to attain.\8\ The EPA's determination of attainment for the 2015
ozone NAAQS is ``based on a nonattainment area's DV as of the
attainment date.''
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\8\ CAA section 181(b)(2).
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The 2015 ozone NAAQS is met at an EPA regulatory monitoring site
when the DV does not exceed 0.070 ppm. For the Moderate nonattainment
areas for the 2015 ozone NAAQS addressed in this action, the attainment
date was August 3, 2024. Because the DV is based on the three most
recent, complete calendar years of data, the EPA's determinations for
each Moderate 2015 ozone NAAQS nonattainment area under CAA section
181(b)(2) are based upon the complete, quality-assured, and certified
ozone monitoring data from calendar years 2021, 2022, and 2023.
At the request of CT DEEP, the Greater Connecticut area was
voluntarily reclassified from Moderate to Serious for the 2015 ozone
NAAQS before the August 3, 2024, nonattainment date.\9\ However, the
tribal portions of the Greater Connecticut area remained classified as
Moderate. The entire Greater Connecticut area, including the tribal
portions, factually failed to attain the 2015 ozone NAAQS. This finding
was not altered by CT DEEP's Exceptional Event (EE) demonstration
discussed in Section I.B. of this action. EPA is proposing to determine
that the tribal portions of the Greater Connecticut area failed to
attain and will be reclassified as Serious for the 2015 ozone NAAQS. If
the EPA determines that a nonattainment area classified as Moderate
failed to attain by the attainment date, CAA section 181(b)(2)(B)
requires the EPA to publish a document in the Federal Register,
identifying each such area and identifying the applicable
reclassification.
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\9\ 89 FR 60827, July 29, 2024.
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3. What is the statutory authority for the proposed actions?
The statutory authority for these determinations is provided by the
CAA, as amended (42 U.S.C. 7401 et seq.). Relevant portions of the CAA
include, but are not necessarily limited to, sections 181 and 182.
As noted earlier, CAA section 107(d) provides that when the EPA
establishes or revises a NAAQS, the agency must designate areas of the
country as nonattainment, attainment, or unclassifiable based on
whether an area is not meeting (or contributing to air quality in a
nearby area that is not meeting) the NAAQS, meeting the NAAQS, or
cannot be classified as meeting or not meeting the NAAQS, respectively.
Subpart 2 of part D of title I of the CAA governs the classification,
state planning, and emissions control requirements for any areas
designated as nonattainment for a revised primary ozone NAAQS. In
particular, CAA section 181(a)(1) requires each area designated as
nonattainment for a revised ozone NAAQS to be classified at the same
time as the area is designated based on the extent of the ozone problem
in the area (as determined based on the area's design value).
Classifications for ozone nonattainment areas range from ``Marginal''
to ``Extreme'' based on the severity of the area's air quality problem.
CAA section 182 provides the specific attainment planning and
additional requirements that apply to each ozone nonattainment area
based on its classification. CAA section 182, as interpreted by the
EPA's implementing regulations in the Code of Federal Regulations (CFR)
at 40 CFR 51.1308 through 51.1317, also establishes the timeframes by
which air agencies must submit and implement SIP revisions to satisfy
the applicable attainment planning elements, and the timeframes by
which nonattainment areas must attain the 2015 ozone NAAQS. For
reclassified areas, CAA section 182(i) provides that the Administrator
may adjust applicable deadlines other than attainment dates if such
adjustment is necessary or appropriate to assure consistency among the
required submissions.
Section 181(b)(2)(A) of the CAA requires that within 6 months
following the applicable attainment date, the EPA shall determine
whether an ozone nonattainment area attained the ozone standard based
on the area's DV as of that date. For nonattainment areas that the EPA
determines have not timely attained, CAA section 181(a)(5) gives the
EPA the discretion to grant a 1-year extension of the attainment date
for qualifying areas upon application by any state. In the event an
area fails to attain the ozone NAAQS by the applicable attainment date
and is not granted a 1-year attainment date extension, CAA section
181(b)(2)(A) requires the EPA to make the determination that an ozone
nonattainment area failed to attain the ozone standard by the
applicable attainment date, and requires the area to be reclassified by
operation of law to the higher of: (1) the next higher classification
for the area, or (2) the classification applicable to the area's design
value as of the determination of failure to attain. Section
181(b)(2)(B) of the CAA required the EPA to publish the determination
of failure to attain and accompanying reclassification in the Federal
Register no later than 6 months after the attainment date, which in the
case of the two tribal territories located in the Greater Connecticut
nonattainment area, was February 3, 2025.
Once an area is reclassified, the state is required to submit
certain SIP revisions in accordance with its more stringent
classification. The SIP revisions are intended to, among other things,
demonstrate how the area will attain the NAAQS as expeditiously as
practicable, but no later than August 3, 2027, the Serious area
attainment date for the 2015 ozone NAAQS. According to CAA section
182(i), a state with a reclassified ozone nonattainment area must
submit the applicable attainment plan requirements ``according to the
schedules prescribed in connection with such requirements'' in CAA
section 182(c) for Serious areas, but the EPA ``may adjust any
applicable deadlines (other than attainment dates) to the extent such
adjustment is necessary or appropriate to assure consistency among the
required submissions.'' EPA has addressed the SIP revision and
[[Page 52300]]
implementation deadlines for newly reclassified Serious areas, as well
as the continued applicability of Moderate area requirements that these
areas may not yet have met, in a separate rulemaking.\10\
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\10\ 90 FR 5651, January 17, 2025.
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Under the CAA and Tribal Authority Rule (TAR), Tribes may, but are
not required to, submit implementation plans to the EPA for
approval.\11\ Accordingly, for the Greater Connecticut nonattainment
area, the Mashantucket Pequot Tribal Nation and the Mohegan Indian
Tribe would not be required to submit any tribal implementation plan
(TIP) revisions applicable to the Serious areas established in CAA
section 182(c) and in the 2015 ozone NAAQS SIP Requirements Rule.
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\11\ CAA section 301(d); 40 CFR part 49.
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4. How does EPA determine whether an area has attained the 2015 ozone
standard?
As discussed earlier, the 2015 ozone NAAQS is attained at a site
when the design value at each ambient air quality monitoring site
within the area does not exceed 0.070 ppm. The rounding convention in
Appendix U dictates that concentrations shall be reported in ``ppm'' to
the third decimal place, with additional digits to the right being
truncated. Thus, a computed 3-year average ozone concentration of 0.071
ppm is greater than 0.070 ppm and would exceed the standard, but a
design value of 0.0709 is truncated to 0.070 and attains the 2015 ozone
NAAQS.
The EPA's determination of attainment by the Moderate attainment
date of August 3, 2024, is based upon hourly ozone concentration data
for calendar years 2021, 2022 and 2023 that have been collected and
quality-assured in accordance with 40 CFR part 58 and reported to the
EPA's Air Quality System (AQS) database.\12\
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\12\ The EPA maintains the AQS, a database that contains ambient
air pollution data collected by the EPA, state, local, and tribal
air pollution control agencies. The AQS also contains meteorological
data, descriptive information about each monitoring station
(including its geographic location and its operator) and data
quality assurance/quality control information. The AQS data is used
to (1) assess air quality, (2) assist in attainment/non-attainment
designations, (3) evaluate SIPs for non-attainment areas, (4)
perform modeling for permit review analysis, and (5) prepare reports
for Congress as mandated by the CAA. Access is through the website
at <a href="https://www.epa.gov/aqs">https://www.epa.gov/aqs</a>.
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B. Exceptional Events
1. What is the background for the proposed action?
Exceptional events are unusual or naturally occurring events that
can affect air quality but are not reasonably controllable using
techniques that tribal, state or local air agencies may implement to
attain and maintain the NAAQS. Exceptional events may include
wildfires, high wind dust events, prescribed fires, stratospheric ozone
intrusions, and volcanic and seismic activities. Under section 319(b)
of the CAA, air agencies can request the exclusion of event-influenced
data when ``exceptional'' events influence monitoring data and cause
exceedances or violations of the NAAQS, and the EPA can agree to
exclude these data, from the data set used for certain regulatory
decisions.
2. Overview of Proposal
On January 10, 2024, the Connecticut Department of Energy and
Environmental Protection (CT DEEP) Bureau of Air Management submitted
an initial notification for an intended EE demonstration, and on July
1, 2024, submitted an EE demonstration for exceedances or violations of
the 2015 ozone NAAQS that occurred at the Cornwall (AQS Site ID
#090050005), East Hartford (AQS Site ID #090031003), and Groton (AQS
Site ID #090110124) monitoring sites in the Greater Connecticut area.
CT DEEP requested that EPA exclude data for April 13-14, June 30-July
1, and July 12, 2023, at the Groton monitoring site, as well as data
for July 1, 2023, at the East Hartford and Cornwall monitoring
locations. The EPA's July 22, 2024, action on the demonstration affects
the determinations of attainment by the attainment date for the Greater
Connecticut area (including the two tribal territories). The EE initial
notification, EE demonstration, the EPA's response to the initial
notification, and EPA's July 22, 2024, decision on the EE demonstration
are provided in the docket for this rulemaking.
II. What is the EPA proposing and what is the rationale?
The EPA is proposing this action to fulfill its statutory
obligation under CAA section 181(b)(2) to determine whether the tribal
portions of the Greater Connecticut area attained the 2015 ozone NAAQS
as of the attainment date of August 3, 2024, and to reclassify both
tribal portions of the area. The two tribal territories are governed by
the Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe.
A. Evaluation of Design Value Data and Exceptional Events Documentation
The EPA evaluated air quality data to determine if the two tribal
portions of the Moderate nonattainment area attained the 2015 ozone
NAAQS by the attainment date of August 3, 2024. The areas' ozone design
values for 2021-2023 are shown in Table 1. Based on the certified,
complete data from 2021-2023, the design value for the tribal portions
of the Greater Connecticut area is 0.072 ppm and the 2023 4th highest
daily maximum 8-hour average is 0.071 ppm.
Table 1--2021-2023 Fourth Highest Daily Maximum 8-Hour Average Ozone Concentrations and Design Values at All Monitors in the Greater Connecticut Area
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Fourth highest daily maximum 8-hour average
ozone concentration (ppm) 2021-2023
AQS site ID County State ------------------------------------------------ design value
2021 2022 2023 (DV) (ppm)
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090031003............................ Hartford................ Connecticut............ 0.066 0.074 0.07 0.07
090050005............................ Litchfield.............. Connecticut............ 0.068 0.07 0.067 0.068
090110124............................ New London.............. Connecticut............ 0.075 0.071 0.071 0.072
090131001............................ Tolland................. Connecticut............ 0.067 0.068 0.07 0.068
090159991............................ Windham................. Connecticut............ 0.068 0.064 0.063 0.065
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On July 1, 2024, CT DEEP submitted an EE demonstration. The EE
demonstration proposed five days to be excluded from the 2023 ozone
season. The EPA's previous action on the demonstration affects the
determination
[[Page 52301]]
of attainment by the attainment date for the Mashantucket Pequot Tribal
Nation and the Mohegan Indian Tribe.\13\ The EE initial notification,
EE demonstration, the EPA's response to the initial notification, and
EPA's decision on the EE demonstration are provided in the docket for
this rulemaking.
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\13\ CAA section 319(b) defines an exceptional event as 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 Administrator through process established
in regulation to be an exceptional event.
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For the Greater Connecticut nonattainment area (including the two
tribal territories) to have an attaining 2021-2023 DV for the 2015
ozone NAAQS, the EPA would have had to concur on all of the requested
air quality monitoring data for exclusion in the EE demonstration that
CT DEEP submitted for 2023. Furthermore, to qualify for an extension of
the attainment date, the EPA would have to concur on all of the air
quality monitoring data requested for exclusion at the Groton (New
London County) monitoring site in the EE demonstration submitted for
2023. The EPA responded to CT DEEP's Initial Notification submittal for
an intended EE demonstration, dated March 7, 2024, indicating that the
events described may affect a future regulatory decision.\14\ Because
regulatory significance is required for EPA concurrence on an EE
demonstration and subsequent exclusion of the event-influenced data
from the design value, the EPA therefore determined it would evaluate
the demonstration submitted by CT DEEP under the Exceptional Events
Rule (EER). The demonstration submitted by CT DEEP stated that the
exceedances measured on April 13-14 were caused by annual agricultural
and prescribed fires from the Flint Hills region of Kansas, and nearby
wildfires from Pennsylvania, New York, and New Jersey. The
demonstration from CT DEEP also stated that there were exceedances or
violations on June 30-July 1 due to Quebec, Canada, wildfires that
transported smoke into the area. CT DEEP also asserted that high levels
of ozone were recorded due to smoke from western Canadian wildfires on
July 12. A summary of CT DEEP's exceptional event demonstration dates,
type of events, and regulatory monitoring sites affected is outlined in
Table 2 below.
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\14\ Letter from L. Hamjian, Director, EPA R1 Air and Radiation
Div., to T. Babbidge, Chief, Bureau of Air management., Conn. Dept.
of Energy and Envtl. Prot. (March 7, 2024).
Table 2--Summary of Critical and Analytically Complex Exceptional Event
Demonstration in Greater Connecticut
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Monitoring sites
Event date Type of event affected
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April 13, 2023.................. Annual Groton (New London
Agricultural and Co.).
Prescribed Fires,
Wildfires.
April 14, 2023.................. Annual Groton (New London
Agricultural and Co.).
Prescribed Fires,
Wildfire.
June 30, 2023................... Wildfire.......... Groton (New London
Co.).
July 1, 2023.................... Wildfire.......... Groton (New London
Co.), East
Hartford
(Hartford Co.),
Cornwall
(Litchfield Co.).
July 12, 2023................... Wildfire.......... Groton (New London
Co.).
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The EPA concurred with CT DEEP's request to exclude data on June 30
and July 1, 2023, at the Groton monitoring site, and on July 1, 2023,
at the East Hartford and Cornwall monitoring sites. However, the EPA
did not concur with CT DEEP's request to exclude data on April 13-14 or
July 12 from the Groton monitoring site. Please refer to the technical
support document for EPA's July 22, 2024, EE decision located in the
docket of this rulemaking for further information regarding EPA's
decision on CT DEEP's EE demonstration.
The 2007 EER and 2016 EER \15\ contain the procedural requirements
and the criteria that the EPA uses to evaluate EE demonstrations. The
demonstration must satisfy all of the EER criteria for the EPA to
concur with excluding the air quality data from regulatory decisions.
If any one of the criteria are not met, the EPA will nonconcur with the
demonstration. In addition to the procedural requirements, the
demonstration must include: (1) a narrative conceptual model describing
the event(s) causing the exceedance or violation and a discussion of
how the emissions from the event(s) led to the exceedance or violation,
(2) a demonstration of a clear causal relationship between the event
and the monitored exceedance or violation, (3) analyses comparing the
event-influenced concentration to concentrations at the same monitoring
site at other times to support the clear causal relationship, (4) a
demonstration that the event was both not reasonably controllable and
not reasonably preventable, and (5) a demonstration that the event was
a human activity unlikely to recur at a particular location or was a
natural event.
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\15\ The EPA promulgated the EER in 2007, pursuant to the 2005
amendment of CAA section 319. In 2016, the EPA finalized revisions
to the EER, which superseded the 2007 EER. The 2007 EER and 2016 EER
revisions added sections 50.1(j)-(r); 50.14; and 51.930 to title 40
of the CFR.
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The EPA found that CT DEEP's demonstration met the Exceptional
Events Rule criteria for some of the dates and monitors as noted above
and determined that wildfire smoke events had regulatory significance
for purposes of calculating the Area's most recent design value. As
such, the EPA is proposing and taking comment on the EPA's July 22,
2024, decision regarding CT DEEP's request to exclude air quality
monitoring data as an exceptional event for regulatory purposes. The
rationale for the EPA's July 22, 2024, exceptional events determination
is detailed in the docket. For this proposed action, the EPA will rely
on the calculated design values that exclude the event-influenced data
for the purpose of determining attainment of the 2015 ozone NAAQS.
Further details on CT DEEP's analyses and the EPA's concurrence and
nonconcurrence, including the exceptional events initial notification,
exceptional events demonstration, the EPA's response to the initial
notification, and EPA's technical support document can be found in the
docket for this rulemaking.
While the EPA has concurred with CT DEEP's request to exclude
event-influenced air quality monitoring data (June 30 and July 1, 2023,
at the Groton monitoring site, and on July 1, 2023, at the East
Hartford and Cornwall monitoring sites) 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. This proposed action provides the public with an opportunity to
comment on the claimed exceptional events, all supporting documents,
and the EPA's concurrence and
[[Page 52302]]
nonconcurrence with CT DEEP's request.
B. Determination of Failure To Attain and Reclassification
The EPA is proposing to determine that the Mashantucket Pequot
Tribal Nation and the Mohegan Indian Tribe portions of the Greater
Connecticut area failed to attain the 2015 ozone NAAQS by the
attainment date of August 3, 2024. Table 1 shows the annual fourth
highest daily maximum 8-hour average ozone concentration and 2021-2023
DV for each monitor in the Greater Connecticut nonattainment area,
which includes the two Tribes' territories.
The tribal portions of the Greater Connecticut area will be
reclassified to Serious, the next higher classification, as provided
under CAA section 181(b)(2)(A)(i) and codified at 40 CFR 51.1303. The
areas are required to attain the standard ``as expeditiously as
practicable'' but no later than 9 years after the initial designation
as nonattainment, which in this case would be no later than August 3,
2027.
C. Serious Area Requirements and Proposed Schedule
Moderate nonattainment areas that failed to attain the 2015 ozone
NAAQS by the attainment date will be reclassified as Serious by
operation of law upon the effective date of the final reclassification
notice. EPA has addressed the Serious area requirements and SIP
submittal schedule for relevant air agencies newly reclassified Serious
areas, as well as the continued applicability of Moderate area
requirements that these areas may not yet have met, in a separate
rulemaking.\16\ As discussed previously, under the CAA and TAR, Tribes
may, but are not required to, submit implementation plans to the EPA
for approval.
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\16\ 90 FR 5651, January 17, 2025.
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III. Proposed Action
EPA is proposing that the tribal portions of the Greater
Connecticut area failed to attain the 2015 ozone standard by the
Moderate area attainment date of August 3, 2024, based on a 2021-2023
DV of 0.072 ppm. CAA section 181(b)(2) requires areas that have failed
to attain by their attainment date be reclassified to the higher of (i)
the next highest classification, or (ii) the classification that
corresponds with the area's DV as of the time that the EPA publishes
the document identifying the areas that have failed to attain by their
attainment date. Accordingly, the EPA is proposing that the tribal
portions of the area, which includes the Mashantucket Pequot Tribal
Nation and the Mohegan Indian Tribe, failed to attain the 2015 ozone
NAAQS by August 3, 2024, and therefore the tribal portions of the
nonattainment area must be reclassified as Serious.
As noted previously, a Tribe that is part of an area that is
reclassified from Moderate to Serious nonattainment is not required to
submit a TIP revision to address new Serious area requirements. Under
the EPA requirements, the NNSR major source threshold and offset
requirements change for stationary sources seeking preconstruction
permits in any nonattainment areas newly classified as Serious,
including on tribal lands. Areas such as the Mashantucket Pequot Tribal
Nation and the Mohegan Indian Tribe that were already classified as
Serious for a previous ozone NAAQS, however, are already subject to
these lower thresholds and higher offset ratios, so a reclassification
to Serious for the 2015 ozone NAAQS would have no effect on the NNSR
permitting requirements for the tribal lands in those areas.\17\ The
EPA is soliciting public comment on the reclassification from Moderate
to Serious nonattainment for the 2015 ozone NAAQS.
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\17\ The Mashantucket Pequot Tribal Nation and Mohegan Indian
Tribe were reclassified as a ``serious'' nonattainment area under
the 2008 Ozone NAAQS on August 23, 2019 (84 FR 44238).
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The EPA is also soliciting public comment on EPA's July 22, 2024,
decision of CT DEEP's exceptional events demonstration to exclude air
quality data from the 2023 ozone season and its decision to nonconcur
on other elements of CT's demonstration. This is in accordance with
EPA's 2016 Exceptional Events Rule (EER).\18\ The EPA is taking comment
for 30 days upon publication of this proposed rule in the Federal
Register. Interested parties may participate in the Federal rulemaking
procedure by submitting written comments to this proposed rule by
following the instructions listed in the ADDRESSES section of this
Federal Register.
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\18\ 81 FR 68216, October 3, 2016.
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IV. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review, and Executive
Order 14094: Modernizing Regulatory Review
This action is not a ``significant regulatory action'' under the
terms of Executive Order 12866 (58 FR 51735, October 4, 1993) and is
therefore not subject to review under Executive Order 14094 (88 FR
21879, April 11, 2023).
B. Executive Order 14192: Unleashing Prosperity Through Deregulation
This action is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because determinations of attainment by the
attainment date under the CAA are exempt from review under Executive
Order 12866.
C. Paperwork Reduction Act (PRA)
This rule does not impose an information collection burden under
the provisions of the PRA of 1995 (44 U.S.C. 3501 et seq.). This action
does not contain any information collection activities and serves only
to propose determinations that the tribal portions of the Greater
Connecticut nonattainment area failed to attain the 2015 ozone
standards by the August 3, 2024, attainment date where such areas will
be reclassified as Serious nonattainment for the 2015 ozone standards.
D. Regulatory Flexibility Act (RFA)
This action is certified as not having a significant economic
impact on a substantial number of small entities under the RFA (5
U.S.C. 601 et seq.). This action will not impose any requirements on
small entities. The determination of failure to attain the 2015 ozone
standards (and resulting reclassifications), do not in and of
themselves create any new requirements beyond what is mandated by the
CAA.
E. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538 and does not significantly or uniquely affect
small governments. The action imposes no enforceable duty on any state,
local or tribal governments or the private sector.
F. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government. The
division of responsibility between the Federal government and the
states for purposes of implementing the NAAQS is established under the
CAA.
G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
Executive Order 13175 (65 FR 67249, November 9, 2000), requires EPA
to develop an accountable process to ensure ``meaningful and timely
input by
[[Page 52303]]
Tribal officials in the development of regulatory policies that have
Tribal implications.'' This action has Tribal implications. However, it
will neither impose substantial direct compliance costs on federally
recognized tribal governments, nor preempt tribal law. As noted
previously, a Tribe that is part of an area that is reclassified from
Moderate to Serious nonattainment is not required to submit a TIP
revision to address new Serious area requirements. However, the EPA is
proposing the determinations of failure to attain in this action.
Ordinarily, the NNSR major source threshold and offset requirements
will change for stationary sources seeking preconstruction permits in
any nonattainment areas newly classified as Serious, including on
tribal lands. Areas that are already classified as Serious for a
previous ozone NAAQS, however, are already subject to these higher
offset ratios and lower thresholds, so a reclassification to Serious
for the 2015 ozone NAAQS would have no effect on the NNSR permitting
requirements for the tribal lands in those areas.
The EPA has communicated with the affected Tribes located within
the boundaries of the nonattainment area addressed in this proposed
rule to inform them of this forthcoming action.
H. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks
EPA interprets Executive Order 13045 (62 FR 19885, April 23, 1997)
as applying to those regulatory actions that concern environmental
health or safety risks that EPA has reason to believe may
disproportionately affect children, per the definition of ``covered
regulatory action'' in section 2-202 of the Executive Order. This
action is not subject to Executive Order 13045 because it does not
establish an environmental standard intended to mitigate health or
safety risks.
I. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use
This action is not subject to Executive Order 13211 (66 FR 28355,
May 22, 2001) because it is not a significant regulatory action under
Executive Order 12866.
J. National Technology Transfer and Advancement Act (NTTAA)
This rulemaking does not involve technical standards. Therefore,
EPA is not considering the use of any voluntary consensus standards.
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Carbon monoxide,
Incorporation by reference, Intergovernmental relations, Lead, Nitrogen
dioxide, Ozone, Particulate matter, Reporting and recordkeeping
requirements, Sulfur oxides, Volatile organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: September 29, 2025.
Mark Sanborn,
Regional Administrator, EPA Region 1.
[FR Doc. 2025-20497 Filed 11-19-25; 8:45 am]
BILLING CODE 6560-50-P
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