# Approval of the Clean Air Act, Section 112(l), Authority for Hazardous Air Pollutants; State of Connecticut Department of Energy and Environmental Protection; Approval of the Clean Air Act Section 502, State Operating Permit Programs, State of Connecticut Department of Energy and Environmental Protection
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Proposed rule.
**SUMMARY:**
The Environmental Protection Agency (EPA) is proposing to approve regulatory amendments that revise two previous program approvals from the Connecticut Department of Energy and Environmental Protection (CT DEEP). The revisions include amendments to the Regulations of Connecticut State Agencies (RCSA) that revise the Connecticut State Operating Permit Program and amendments to RCSA that revise limitations on potential to emit Clean Air Act (CAA) pollutants. A significant aspect of this action involves revising the definition of “hazardous air pollutant” in the RCSA in response to EPA adding 1-bromopropane to the list of hazardous air pollutants. This action is being taken under the Clean Air Act.
**DATES:**
Written comments must be received on or before September 29, 2025.
**ADDRESSES:**
Submit your comments, identified by Docket ID No. EPA-R01-OAR-2025-0655 at *https://www.regulations.gov,* or via email to *[email protected]* . For comments submitted at *Regulations.gov* , follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from *Regulations.gov* . For either manner of submission, 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 *https://www.epa.gov/dockets/commenting-epa-dockets* . Publicly available docket materials are available at *https://www.regulations.gov* 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:**
Liam Numrich, Air Permits, Toxics, and Indoor Programs 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 617-918-1307, *[email protected]* .
**SUPPLEMENTARY INFORMATION:**
Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA.
**Table of Contents**
I. Background and Purpose
II. Review of Connecticut State Operating Permit Program Revisions and Amendments to Air Quality Regulations
III. EPA's Analysis of CT DEEP's Title V Program Revisions and 112(l) State Program Revisions
IV. Proposed Action
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews
**I. Background and Purpose**
The Clean Air Act Amendments of 1990 required all state and local permitting authorities to develop operating permit programs that meet certain federal criteria. (42 U.S.C. 7661-7661e.) In implementing the operating permit programs, the permitting authorities require certain sources of air pollution to obtain permits that contain all applicable requirements under the CAA. The focus of the operating permit program is to improve compliance and enforcement by issuing each source a permit that consolidates all of the applicable CAA requirements into a federally enforceable document. By consolidating all of the applicable requirements, the source, the public, and the permitting authorities can more easily determine what CAA requirements apply and how to determine compliance with those requirements.
Sources required to obtain an operating permit under this program include “major” sources of air pollution and certain other sources specified in the CAA or in EPA's implementing regulations. (See 40 CFR 70.3.) For example, all sources regulated under the acid rain program, regardless of size, must obtain operating permits. (See 40 CFR 72.30.) Examples of major sources include: those that have the potential to emit 100 tons per year or more of volatile organic compounds, carbon monoxide, lead, sulfur dioxide, nitrogen oxides, or particulate matter (PM 10); those that emit 10 tons per year of any single hazardous air pollutant (HAP); or those that emit 25 tons per year or more of a combination of HAPs. (40 CFR 70.2.) In areas that are not meeting the National Ambient Air Quality Standards for ozone, carbon monoxide, or particulate matter, major sources are defined by the gravity of the nonattainment classification. ( *Id.* ) The Connecticut State Operating Permit Program's initial approval became effective on May 31, 2002. (67 FR 31966.)
Section 112(b) of the CAA established a list of 189 HAP. This provision of the CAA also provides the EPA with the authority to modify the list. In response to a petition to the Administrator to list 1-bromopropane or 1-BP (also known as n-propyl bromide (nPB)), the EPA, for the first time, added a new HAP to the CAA section 112(b) HAP list (HAP list) on January 5, 2022. (87 FR 393.) This new addition to the HAP list prompted updates to Connecticut's definition of “hazardous air pollutant” in the RSCA in order to keep Connecticut's regulations consistent with listing or delisting chemical compounds from the federal HAP list.
The Administrator may, under the authority of section 112(l) and 40 CFR 63.91, approve a State program designed to establish limits on the potential to emit HAP listed pursuant to section 112 of the CAA. Any request for approval under this subpart shall meet all section 112(l) approval criteria specified by the otherwise applicable Federal section 112 rule, emission standard, or requirement. Approval of the rule delegates to the State the authority to implement and enforce the approved rule in lieu of the otherwise applicable Federal section 112 rule. CT DEEP's 112(l) program was approved on April 11, 2022.
On June 14, 2024, CT DEEP submitted revisions to its State Operating Permit Program and to its Approved Limitations on Potential to Emit CAA Section 112 pollutants to EPA. These amendments revise two previous program approvals for EPA's approval. They consist of (1) amendments to sections 22a-174-1 (Definitions) and 22a-174-33 (Title V sources) of the RCSA that revise the Connecticut State Operating Permit Program; and (2) amendments to RCSA sections 22a-174-1, 22a-174-33a (Limit on Premises-Wide Actual Emissions Below 50% of Title V Source Thresholds), and 22a-174-33b (Limit on Premises-Wide Actual Emissions Below 80% of Title V Source Thresholds) that revise limitations on potential to emit CAA section 112 pollutants for the state's CAA section 112(l) state program to limit the potential to emit HAP pollutants below Title V source thresholds.
**II. Review of Connecticut State Operating Permit Program Revisions and Amendments to Air Quality Regulations**
In accordance with Title V program revisions required at 40 CFR 70.4(i)(2) and CAA 112(l) state program revision requirements at 40 CFR 63.91, the primary change in CT DEEP's June 14, 2024, submittal is a new definition of “hazardous air pollutant” in RCSA section 22a-174-1. The current definition of “hazardous air pollutant” is deleted and replaced with the following: `Hazardous air pollutant,' `Federal hazardous air pollutant' or `HAP,' except as otherwise provided in section 22a-174-29 of the Regulations of Connecticut State Agencies, means any air pollutant listed in section 112(b)(1) of the Act, inclusive of deletions and additions set out in 40 CFR part 63, subpart C, as may be amended from time to time.”
This new definition is consistent with EPA's most recent change to the federal definition of HAP to include 1-bromopropane in the list of HAP established under the CAA section 112 program. The new definition also incorporates future changes to the federal definition resulting from EPA's listing or delisting of a chemical compound.
CT DEEP submitted companion changes to RCSA section 22a-174-33a(a)(4) and RCSA section 22a-174-33b(a)(10) to effectuate the change in the definition of “hazardous air pollutant” at RCSA section 22a-174-1 into those two regulations as they regulate HAP emissions as a CAA section 112(l) state program.
In addition to this change, there are a number of revisions to CT DEEP's Title V operating permit program at RCSA section 22a-174-33 to correct citations to another Connecticut air quality regulation. The corrections will better ensure that Title V applications, notifications, reports, and records are properly certified by a responsible official, and are as follows:
• RCSA section 22a-174-33(g)(1)(G). The internal citation to section 22a-174-2a(a)(5) is corrected to 22a-174-2a(a)(4).
• RCSA section 22a-174-33(h)(2). The internal citation to section 22a-174-2a(a)(5) is corrected to 22a-174-2a(a)(4).
• RCSA section 22a-174-33(o)(4). The internal citation to section 22a-174-2a(a)(5) is corrected to 22a-174-2a(a)(4).
• RCSA section 22a-174-33(p)(3). The internal citation to section 22a-174-2a(a)(5) is corrected to 22a-174-2a(a)(4).
• RCSA section 22a-174-33(q)(1). The internal citation to section 22a-174-2a(a)(5) is corrected to 22a-174-2a(a)(4).
• RCSA section 22a-174-33(q)(2). The internal citation to section 22a-174-2a(a)(5) is corrected to 22a-174-2a(a)(4).
**III. EPA's Analysis of CT DEEP's Title V Program Revisions and 112(l) State Program Revisions**
EPA's analysis of Connecticut's submittal finds the revisions necessary for maintaining consistency between state regulations and federal regulations. Due to the addition of 1-bromopropane as a HAP under the CAA, the change to the definition of “hazardous air pollutant” in RCSA ensures that Connecticut state regulations will include all HAPs, which is necessary in their Title V program and 112 program. The other changes to Connecticut's Title V program are administrative in nature and are also approvable.
**IV. Proposed Action**
EPA is proposing to approve Connecticut's revisions to its Title V Operating Permit program and CAA section 112(l) state program revision. Specifically, EPA is proposing to approve revisions to RCSA section 22a-174-1 and RCSA section 22a-174-33 as Title V program revisions and RCSA section 22a-174-1, RCSA section 22a-174-33a and RCSA section 22a-174-33b as CAA section 112(l) state program revision.
EPA is soliciting public comments on the issues discussed in this notice or on other relevant matters. These comments will be considered before taking final action. 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* .
**V. Incorporation by Reference**
In this rule, the EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference the CT DEEP rules regarding definitions and permitting requirements discussed in sections I and II of this preamble. The EPA has made, and will continue to make, these documents generally available through *https://www.regulations.gov* and at the EPA Region 1 Office (please contact the person identified in the *FOR FURTHER INFORMATION CONTACT* section of this preamble for more information).
**VI. Statutory and Executive Order Reviews**
Under the Clean Air Act, the Administrator is required to approve CAA Section 112(l) and Title V submissions that comply with the provisions of the Clean Air Act and applicable Federal regulations. Thus, in reviewing submissions, EPA's role is to approve state choices, provided that they meet the criteria of the Clean Air Act. Accordingly, this proposed action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:
• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, October 4, 1993);
• 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 Clean Air Act.
In addition, the submission is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the rule does not have tribal implications and will not impose substantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
**List of Subjects**
Environmental protection, Administrative practice and procedure, Air pollution control, Hazardous substances, Incorporation by reference, Intergovernmental relations, Reporting and recordkeeping requirements.
Acid rain, Administrative practice and procedure, Air pollution control, Environmental protection, Hazardous substances, Incorporation by reference, Intergovernmental relations, Licensing and registration, Reporting and recordkeeping requirements.
**Authority:**
42 U.S.C. 7401 *et seq.*
Dated: July 30, 2025.
Mark Sanborn,
Regional Administrator, EPA Region 1.