# Air Plan Approval; Connecticut; Ozone Ambient Air Quality Standard and Adhesive and Sealants Regulation Revisions
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Proposed rule.
**SUMMARY:**
The Environmental Protection Agency (EPA) is proposing to approve a State Implementation Plan (SIP) revision submitted by the State of Connecticut. This revision updates state regulations containing ambient air quality standards (AAQS) for ozone to be consistent with EPA's national ambient air quality standards (NAAQS). In addition, this update clarifies the volatile organic compound (VOC) calculation methods for adhesive and sealant products. The intended effect of this action is to propose approval of these regulations into the Connecticut SIP. This action is being taken under the Clean Air Act.
**DATES:**
Written comments must be received on or before December 22, 2025.
**ADDRESSES:**
Submit your comments, identified by Docket ID No. EPA-R01-OAR-2025-1311 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:**
Laura Berman, Energy and Resilience Branch, U.S. Environmental Protection Agency, EPA Region 1, 5 Post Office Square—Suite 100, (Mail code 5-MI), Boston, MA 02109-3912, tel. (617) 918-1856, email *[email protected].*
**SUPPLEMENTARY INFORMATION:**
Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA.
**Table of Contents**
I. Background and Purpose
A. The 2015 Ozone NAAQS
B. Ozone Transport Commission Model Rule for Adhesives and Sealants
II. EPA's Evaluation of Connecticut's Submittal
A. RCSA 22a-174-24
B. RCSA 22a-174-44
III. Proposed Action
IV. Incorporation by Reference
V. Statutory and Executive Order Reviews
**I. Background and Purpose**
On April 30, 2025, the Connecticut Department of Energy and Environmental Protection (CT DEEP) submitted a revision to its State Implementation Plan for sections 22a-174-24 and 22a-174-44 of the Regulations of Connecticut State Agencies (RCSA). The revision consists of adding the 0.070 parts per million ozone standard in RCSA 22a-174-24 and clarifying the volatile organic compound calculation methods available for adhesive and sealant products in RCSA 22a-174-44.
**A. The 2015 Ozone NAAQS**
Section 109 of the Clean Air Act (CAA) directs EPA to establish National Ambient Air Quality Standards requisite to protect public health with an adequate margin of safety (primary standard) and for the protection of public welfare (secondary standard). Sections 109(d)(1) of the CAA requires EPA to complete a thorough review of the NAAQS at 5-year intervals and promulgate new standards when appropriate. Additionally, Section 107 of the CAA requires the establishment of air quality control regions for the purpose of implementing the NAAQS.
On October 26, 2015, EPA revised both the primary and secondary NAAQS for ozone to a level of 0.070 parts per million (ppm) to provide increased protection of public health and the environment ( *See* 80 FR 65292). This final ozone rule became effective on December 28, 2015.
**B. Ozone Transport Commission Model Rule for Adhesives and Sealants**
The Ozone Transport Commission (OTC) is a multi-state organization created under Section 184 of the Clean Air Act. The OTC is responsible for advising EPA on developing and implementing regional solutions to the ground-level ozone problem in the Northeast and Mid-Atlantic regions. The OTC committees develop consensus-based model rules and guidelines for use by their members at their discretion. The OTC itself is not a regulatory authority and does not adopt these as requirements for the region. Each OTC member that opts to adopt a model rule or guideline may modify it according to its own circumstances, and each OTC member is the primary authority on interpreting its rules and guidelines within its jurisdiction.
On December 7, 2006, the OTC issued the OTC Model Rule of Adhesives and Sealants. [^1] The provisions of this model rule limit emissions of VOCs from adhesives, sealants and primers. The model rule achieves VOC reductions through two basic components: sale and manufacture restrictions that limit the VOC content of specified adhesives, sealants and primers sold in the state; and use restrictions that apply primarily to commercial/industrial applications. By reducing the availability of higher VOC content adhesives and sealants within the state, the sales prohibition is also intended to address adhesive and sealant usage at area sources. Emissions from residential use of regulated products are addressed through the sales restrictions and simple use provisions. The model rule is based on a 1998 reasonable available control technology (RACT) determination prepared by the California Air Resources Board (CARB). [^2] On April 2, 2024, the OTC issued corrective/clarifying revisions to the model rule to clarify the VOC calculation methods available for adhesive and sealant products. [^3]
[^1]*See* OTC Model Rule for Adhesives and Sealants.
[^2]*See* CARB Determination of Reasonably Available Control Technology and Best Available Retrofit Control Technology for Adhesives and Sealants.
[^3]*See* OTC Model Rules and Guidelines.
**II. EPA's Evaluation of Connecticut's Submittal**
**A. RCSA 22a-174-24**
Connecticut's April 30, 2025, SIP submittal includes revisions to RCSA section 22a-174-24, “Connecticut primary and secondary ambient air quality standards.” Specifically, CT DEEP is revising subsection (i) of section 22a-174-24 by adding subdivision (3) into Connecticut's SIP. This regulation has been revised to maintain consistency between the Connecticut AAQS and EPA's NAAQS for ozone. Specifically, Connecticut adopted the 2015 ozone primary and secondary 8-hour standards of 0.070 parts per million. A copy of CT DEEP's revisions to RCSA section 22a-174-24 is located in the docket of this proposed rulemaking. [^4]
[^4]*See* State Implementation Plan Revision Concerning Minor Revisions to Two Air Quality Regulations: Attachment A-2, Changes to the State Implementation Plan Resulting from the Amendment of RCSA Sections 22a-174-24 and 22a-174-44 (p. 14).
Connecticut's air quality standards rule, RCSA section 22a-174-24, as well as amendments to this rule, have been previously approved into the Connecticut SIP, with the most recent approval occurring on June 24, 2015 ( *See* 80 FR 36242). EPA has reviewed Connecticut's revisions to its ambient air quality standards, definitions, and references and has determined they are consistent with the federal NAAQS in 40 CFR part 50. Connecticut's revised RCSA section 22a-174-24 includes additional and more stringent air quality standards than the previous SIP-approved version of this rule. Thus, the revised RCSA section 22a-174-24 satisfies the anti-backsliding requirements in Section 110(l) of the CAA and we are proposing to approve Connecticut's revised rule into the Connecticut SIP.
**B. RCSA 22a-174-44**
Connecticut's April 30, 2025, SIP submittal includes revisions to RCSA section 22a-174-44, “Adhesives and sealants.” Specifically, CT DEEP is revising subdivision (2) of subsection (e) of section 22a-174-44 in Connecticut's SIP. This regulation has been revised to correct the VOC calculation methods for adhesive and sealant products. Specifically, the correction clarifies the VOC content determinations for low-solids adhesives, sealants, adhesive primers and sealant primers as set out in subparagraph (C) of subdivision (2). Additionally, this correction clarifies the calculation methodology for non-low solids adhesives, sealants, adhesive primers and sealant primers. A copy of CT DEEP's revisions to RCSA section 22a-174-44 is located in the docket of this proposed rulemaking. [^5]
[^5]*See* State Implementation Plan Revision Concerning Minor Revisions to Two Air Quality Regulations: Attachment A-2, Changes to the State Implementation Plan Resulting from the Amendment of RCSA Sections 22a-174-24 and 22a-174-44 (p. 14-16).
Connecticut's adhesives and sealants rule, RCSA section 22a-174-44, has been previously approved into the Connecticut SIP on June 9, 2014 ( *See* 79 FR 32873). RCSA section 22a-174-44 is based on the OTC Model Rule for Adhesives and Sealants and includes the calculation methods available for adhesive and sealant products from the OTC Model Rule. EPA has reviewed Connecticut's revisions to its adhesives and sealants rule and has determined they are consistent with the revised April 2, 2024, OTC Model Rule for Adhesives and Sealants. EPA is proposing to approve Connecticut's revised rule into the Connecticut SIP.
**III. Proposed Action**
EPA is proposing to approve Connecticut's April 30, 2025 SIP revision to their RCSA 22a-174-24 and 22a-174-44, and incorporate each into the Connecticut SIP. 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* .
**IV. 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 changes to Connecticut RCSA sections 22a-174-24 and 22a-174-44 as adopted on April 2, 2025, and described in section II. of this preamble. The changes primarily update the AAQS to match the primary and secondary NAAQS for ozone and clarifies VOC calculation methods for adhesive and sealant products. 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).
**V. Statutory and Executive Order Reviews**
Under the Clean Air Act, the Administrator is required to approve a SIP submission that complies with the provisions of the Clean Air Act and applicable Federal regulations. *See* 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 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);
• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review 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 (Public Law 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 SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the rule does not have tribal implications and will not impose substantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
**List of Subjects in 40 CFR Part 52**
Environmental protection, Air pollution control, Incorporation by reference, Ozone, Reporting and recordkeeping requirements, Volatile organic compounds.
**Authority:**
42 U.S.C. 7401 *et seq.*
Dated: October 1, 2025.
Mark Sanborn,
Regional Administrator, EPA Region 1.