Air Plan Approval; Connecticut; State Implementation Plan Revisions Required as a Result of a Definition Change Due to the Ozone Reclassification

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R01-OAR-2025-0196; FRL-12890-01-R1]</DEPDOC> <SUBJECT>Air Plan Approval; Connecticut; State Implementation Plan Revisions Required as a Result of a Definition Change Due to the Ozone Reclassification</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing to approve a State Implementation Plan (SIP) revision submitted by the State of Connecticut. This action consists of revisions to Regulations of Connecticut State Agencies (RCSA) sections 22a-174-22e and 22a-174-22f, primarily to add compliance dates for sources brought into the applicability of these sections due to a change in the definition of “severe non-attainment area for ozone,” The definition change had previously been approved into Connecticut's SIP. This action is being taken in accordance with the Clean Air Act. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before August 15, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R01-OAR-2025-0196 at <E T="03">https://www.regulations.gov,</E> or via email to <E T="03">creilson.john@epa.gov.</E> For comments submitted at <E T="03">Regulations.gov,</E> follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from <E T="03">Regulations.gov.</E> 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 ( <E T="03">i.e.</E> on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the <E T="02">For Further Information Contact</E> section. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">https://www.epa.gov/dockets/commenting-epa-dockets.</E> Publicly available docket materials are available at <E T="03">https://www.regulations.gov</E> 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 possible, you contact the person listed in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section to schedule your inspection. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> John Creilson, Air Quality Branch, U.S. Environmental Protection Agency, EPA New England Regional Office, 5 Post Office Square, Suite 100 (mail code 5-MI), Boston, MA 02109-3912, telephone number (617) 918-1688, email <E T="03">creilson.john@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA. <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. Background</FP> <FP SOURCE="FP-2">II. Summary and Evaluation of Connecticut's SIP Revision</FP> <FP SOURCE="FP-2">III. Proposed Action</FP> <FP SOURCE="FP-2">IV. Incorporation by Reference</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> On November 27, 2023, the Connecticut Department of Energy and Environmental Protection (CT DEEP) submitted a revision to its State Implementation Plan (SIP). This action consists of revisions to Regulations of Connecticut State Agencies (RCSA) sections 22a-174-22e and 22a-174-22f, primarily to add compliance dates for sources brought into the applicability of these sections due to a change in the definition of “severe non-attainment area for ozone” in another section of Connecticut's regulations—specifically, RCSA § 22a-174-1. The revisions to RCSA §§ 22a-174-22e and 22a-17422f became effective on November 13, 2023. Connecticut's change to the definition of “severe non-attainment area for ozone” in RCSA § 22a-174-1 became effective the same day, and the Environmental Protection Agency (EPA) previously approved the new definition into the SIP on February 12, 2024 (89 FR 9771). On March 20, 2023, CT DEEP proposed changes to the definition of “severe non-attainment area for ozone” within RCSA § 22a-174-1. The proposed change to the definition expanded the list of cities and towns in the definition, to include all cities and towns in New Haven County and Middlesex County. CT DEEP also retained the two towns in Litchfield County to ensure classification consistency in these communities and to comply with section 193 of the Clean Air Act (CAA), which prohibits any control measure in effect in a nonattainment area prior to the enactment of the CAA Amendments of 1990 to be modified after enactment, unless such modification yields equivalent or greater emission reductions. As a result of this definition change and as described in 89 FR 9771, the number of towns included in the “severe non-attainment area for ozone” increased, making RCSA §§ 22a-174-22e and 22a-174-22f applicable to more sources. The entire state of Connecticut is divided into two nonattainment areas for ozone. One area consists of the southwest portion of the state (the Connecticut portion of the New York-New Jersey-Connecticut area), and the remainder of the state (Greater Connecticut) makes up the other nonattainment area. The area in the southwest portion of the state generally experiences higher ozone levels, and on October 7, 2022, the EPA published a final rule to reclassify, among other areas, the southwest Connecticut ozone nonattainment area to severe nonattainment from serious nonattainment based on the area's inability to attain the 2008 ozone National Ambient Air Quality Standard (NAAQS) by the attainment date (87 FR 60926). Connecticut regulations define nonattainment areas in a geographic manner. The original definition of “severe non-attainment area for ozone” in RCSA § 22a-174-1, was based on the nonattainment area designation under the 1-hour ozone NAAQS of 1979. The area included all towns and cities in Fairfield County, except the town of Shelton, and two towns in Litchfield County (Bridgewater and New Milford). Currently, the southwest Connecticut ozone nonattainment area for the 2008 ozone NAAQS is larger than the older area for the 1979 ozone NAAQS, and it includes all of Fairfield County, New Haven County, and Middlesex County. <HD SOURCE="HD1">II. Summary and Evaluation of Connecticut's SIP Revision</HD> Sections 22a-174-22e and 22a-174-22f of the RCSA impose requirements on sources based in part on the classification of the nonattainment area in which the source is located, and the quantity of emissions released. Sources emitting over certain threshold amounts of nitrogen oxides (NO <E T="52">X</E> ) are subject to the control requirements of RCSA section 22a-174-22e. As a result of the revision to the definition of “severe non-attainment area for ozone,” RCSA §§ 22a-174-22e and 22a-174-22f became newly applicable to certain sources in Towns that were added to the definition. As Connecticut's regulatory revisions bring new sources under RCSA section 22a-174-22e, new provisions were necessary to specify the timing of compliance and of certain submissions the new sources must provide to CT DEEP. The main changes for section 22a-174-22e are (1) the addition of a definition for “Bumped-up RACT unit” in subsection (a), and (2) the addition of subsection (n), “Compliance by bumped-up RACT units.” Connecticut defines a “Bumped-up RACT unit” as “an emission unit located at a facility with a potential to emit NO <E T="52">X</E> of not less than twenty-five (25) tons per year whereby such facility becomes a major stationary source of NO <E T="52">X</E> on or after November 7, 2022 solely as a result of the amendment of the definition of `severe non-attainment area for ozone' in RCSA section 22a-174-1 effective on November 13, 2023.” The revisions to § 22a-174-22e require such a bumped-up reasonably available control technology (RACT) unit to comply with emissions limitations already applicable to other sources covered by § 22a-174-22e, providing a timeframe for that compliance, pursuant to certain conditions. Connecticut also made minor corrections or updates to several provisions in RCSA § 22a-174-22e based on the two changes described above. Finally, Connecticut added timing provisions to RCSA § 22a-174-22f coordinated with those of § 22a-174-22e. This action will ensure that Connecticut is applying RACT requirements and other NO <E T="52">X</E> control requirements to the appropriate sources in the state, thereby meeting nonattainment requirements for ozone as set out in Section 182(d) of the CAA. The EPA has reviewed Connecticut's November 27, 2023, submittal of revisions to RCSA §§ 22a-174-22e and 22a-174-22f and preliminarily determined that they represent approvable revisions to the versions previously approved into the Connecticut SIP. These revisions will appropriately apply requirements to sources in line with Connecticut's change to the definition of “severe non-attainment area for ozone” that the EPA previously approved into the SIP. (89 FR 9771). <HD SOURCE="HD1">III. Proposed Action</HD> The EPA is proposing to approve Connecticut's November 27, 2023, SIP submittal that addresses revisions t ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 14k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━