# Air Plan Approval; Arizona; Maricopa County Air Quality Department; Volatile Organic Compounds; Architectural Coatings
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Proposed rule.
**SUMMARY:**
The Environmental Protection Agency (EPA) is proposing to approve revisions to the Maricopa County Air Quality Department (MCAQD or “County”) portion of the Arizona State Implementation Plan (SIP). These revisions concern emissions of volatile organic compounds (VOC) from architectural coatings. Architectural coatings include house paints, stains, industrial maintenance coatings, traffic coatings, and other similar products. We are proposing to approve local rules to regulate these emission sources under the Clean Air Act (CAA or “Act”). The revisions would update the Arizona SIP by replacing an outdated rule version with the current version in effect and would lower VOC emissions limits for some architectural coatings if contingency measures are triggered in the future. We are taking comments on this proposal and plan to follow with a final action.
**DATES:**
Comments must be received on or before October 14, 2025.
**ADDRESSES:**
Submit your comments, identified by Docket ID No. EPA-R09-OAR-2025-0317 at *https://www.regulations.gov.* For comments submitted at *Regulations.gov* , follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from *Regulations.gov* . 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.* If you need assistance in a language other than English or if you are a person with a disability who needs a reasonable accommodation at no cost to you, please contact the person identified in the *FOR FURTHER INFORMATION CONTACT* section.
**FOR FURTHER INFORMATION CONTACT:**
Allison Kawasaki, EPA Region IX, 75 Hawthorne St., San Francisco, CA 94105; telephone number: (415) 972-3922; email address: *[email protected].*
**SUPPLEMENTARY INFORMATION:**
Throughout this document, “we,” “us,” and “our” refer to the EPA.
**Table of Contents**
I. The State's Submittal
A. What rules did the State submit?
B. Are there other versions of these rules?
C. What is the purpose of the submitted rule revisions?
II. The EPA's Evaluation and Action
A. How is the EPA evaluating the rules?
B. Do the rules meet the evaluation criteria?
C. The EPA's Recommendations To Further Improve the Rules
D. Proposed Action and Public Comment
III. Incorporation by Reference
IV. Statutory and Executive Order Reviews
**I. The State's Submittal**
**A. What rules did the State submit?**
Table 1 lists the rules addressed by this proposal with the dates that they were adopted by the local air agency and submitted to the EPA by the Arizona Department of Environmental Quality (ADEQ). This proposal addresses two versions of MCAQD Rule 335—Architectural Coatings (“Rule 335”). Because these rules have identical titles and are regulating the same source category they will be differentiated in this proposal by the year in which they were submitted to the EPA. On September 8, 2017, ADEQ submitted a SIP revision requesting that the EPA approve Rule 335, as revised on September 25, 2013, into the Maricopa County portion of the Arizona SIP (“2017 submittal”). On December 23, 2024, ADEQ submitted a SIP revision requesting that the EPA approve Rule 335, as revised on December 11, 2024, into the Maricopa County portion of the Arizona SIP (“2024 submittal”).
| Local | Rule No. | Rule title | Revised | Submitted |
| --- | --- | --- | --- | --- |
| MCAQD | 335 | Architectural Coatings | September 25, 2013 | September 8, 2017. |
| MCAQD | 335 | Architectural Coatings | December 11, 2024 | December 23, 2024. |
On March 13, 2018, the 2017 submittal was deemed by operation of law to be complete. On June 11, 2025, the 2024 submittal was deemed by operation of law to be complete. We have reviewed the submittals to ensure they meet the completeness criteria in 40 CFR part 51, appendix V.
**B. Are there other versions of these rules?**
We approved an earlier version of Rule 335 (adopted on July 13, 1988) into the SIP on January 6, 1992 (57 FR 354). In both the 2017 submittal and 2024 submittal, ADEQ requested that, upon approval of the revised version of Rule 335, the EPA remove the 1988 version of this rule from the SIP. If we finalize this rulemaking as proposed, then both the 2017 submittal and 2024 submittal of Rule 335 will replace the 1988 version of this rule in the SIP. The 2024 submittal of Rule 335 will not become effective until and unless contingency measures are triggered for the 2015 8-hour ozone national ambient air quality standards (NAAQS).
**C. What is the purpose of the submitted rule revisions?**
Rule 335 regulates the emissions of VOC from architectural coatings. Architectural coatings are coatings that are applied to stationary structures and their accessories. They include house paints, stains, industrial maintenance coatings, traffic coatings, and other similar products. VOC is emitted from coatings during application, curing, and from the associated solvents used for thinning and clean-up. Emissions of VOC contribute to the production of ground-level ozone and particulate matter (PM), which harm human health and the environment. Section 110(a) of the CAA requires states to submit regulations that control VOC emissions.
The 2017 submittal of Rule 335 was submitted as part of an ongoing effort by the MCAQD and the EPA to update the Maricopa County portion of the Arizona SIP to reflect the current locally adopted rules. The 2024 submittal of Rule 335 was adopted by MCAQD to meet CAA requirements related to contingency measures. Reductions in VOC emissions from architectural coatings can be achieved by limiting the VOC content of coatings. Under CAA 179(c)(9), states must adopt contingency measures for nonattainment areas that become effective in the event the EPA makes a finding of a failure to attain a NAAQS or a finding of failure to make reasonable further progress. If contingency measures are triggered for the 2015 8-hour ozone NAAQS, lower VOC content limits will apply to coatings in these categories: flat coatings, non-flat coatings, dry fog coatings, industrial maintenance coatings, primers, sealers, undercoaters, roof coatings, specialty primers, stains, traffic marking coatings, and wood preservatives.
The EPA prepared a technical support document (TSD) for each submittal of Rule 335. These TSDs are available in the docket and have more information about these rules.
**II. The EPA's Evaluation and Action**
**A. How is the EPA evaluating the rules?**
Rules in the SIP must be enforceable and must not interfere with applicable requirements concerning attainment and reasonable further progress or other CAA requirements. They also must not modify certain SIP control requirements in nonattainment areas that were in effect before November 15, 1990, without ensuring equivalent or greater emissions reductions. See, respectively, CAA sections 110(a)(2), 110(l), and 193.
Guidance and policy documents that we used to evaluate enforceability, revision/relaxation, and rule stringency requirements for the applicable criteria pollutants include the following:
1.“State Implementation Plans; General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990,” 57 FR 13498 (April 16, 1992); 57 FR 18070 (April 28, 1992).
2.“Issues Relating to VOC Regulation Cutpoints, Deficiencies, and Deviations,” EPA, May 25, 1988 (the Bluebook, revised January 11, 1990).
3. “Guidance Document for Correcting Common VOC & Other Rule Deficiencies,” EPA Region 9, August 21, 2001 (the Little Bluebook).
**B. Do the rules meet the evaluation criteria?**
We evaluated these rules to ensure they meet CAA requirements and are consistent with relevant guidance regarding enforceability and SIP revisions. The version of Rule 335 in the 2024 submittal does not become effective unless the EPA makes one of the findings that triggers contingency measures for the 2015 8-hour ozone NAAQS. As a result, the 2017 submittal of Rule 335 has not been superseded and we are proposing to approve both the 2017 submittal of Rule 335 and the 2024 submittal of Rule 335 to replace the current version in the SIP from 1988. This ensures treatment of the two rule versions in the SIP will be consistent with how they are being implemented locally.
For the 2017 submittal of Rule 335, MCAQD only made minor changes to the rule compared to the SIP-approved version from 1988. The changes were limited to removal of two definitions that are already approved elsewhere into the SIP and are still incorporated into Rule 335. These revisions do not relax any current SIP requirements and are approvable under CAA sections 110(l) and 193.
The 2024 submittal of Rule 335 was evaluated to ensure enforceability under CAA section 110(a)(2)(A) and compliance with the SIP revision requirements in CAA section 110(l) and 193. MCAQD made more substantial revisions to this version, including establishing more stringent VOC emissions limitations if the Phoenix-Mesa ozone nonattainment area triggers contingency measure requirements. MCAQD also made significant revisions to the definitions and categories of coatings covered by the rule. We are proposing that the 2024 submittal of Rule 335 complies with CAA sections 110(a)(2)(A), 110(l), and 193.
In this proposal we are not evaluating whether the 2024 submittal of Rule 335 meets the contingency measure requirements in CAA section 179(c)(9). That evaluation will be addressed in a separate rulemaking. The TSDs for each rule have more information on our evaluation.
**C. The EPA's Recommendations To Further Improve the Rules**
The TSDs include recommendations for the next time the local agency revises the rules.
**D. Proposed Action and Public Comment**
As authorized in section 110(k)(3) of the Act, the EPA proposes to approve the submitted rules because they fulfill all relevant requirements. We are also proposing to rescind the current SIP-approved version of Rule 335 (adopted on July 13, 1988) and replace it with the versions of Rule 335 in the 2017 submittal and 2024 submittal. We will accept comments from the public on this proposal until October 14, 2025. If we take final action to approve the submitted rules, our final action will incorporate these rules into the federally enforceable SIP.
**III. Incorporation by Reference**
In this document, 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 MCAQD Rule 335, Architectural Coatings, revised on September 25, 2013, and MCAQD Rule 335, Architectural Coatings revised on December 11, 2024, which regulate VOC emissions from architectual coatings. The EPA has made, and will continue to make, these materials available through *https://www.regulations.gov* and at the EPA Region IX Office (please contact the person identified in the *FOR FURTHER INFORMATION CONTACT* section of this preamble for more information).
**IV. Statutory and Executive Order Reviews**
Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the Act and applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this proposed action merely proposes to approve 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 Order 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 (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 proposes to approve 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 the 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, Intergovernmental relations, Nitrogen oxides, Ozone, Reporting and recordkeeping requirements, Volatile organic compounds.
Dated: September 3, 2025.
Michael Martucci,
Acting Regional Administrator, Region IX.