# Air Plan Approval; Oklahoma; Revisions to Air Pollution Control Rules
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Proposed rule.
**SUMMARY:**
Pursuant to the Clean Air Act (CAA or the Act), the Environmental Protection Agency (EPA) is proposing to approve revisions to the State Implementation Plan (SIP) for Oklahoma submitted by the State of Oklahoma on November 25, 2024. The submittal addresses updates to the Oklahoma SIP, specifically, Oklahoma Administrative Code (OAC) Title 252 Chapter 100 Subchapter 13, Open Burning.
**DATES:**
Written comments must be received on or before August 6, 2025.
**ADDRESSES:**
Submit your comments, identified by Docket No. EPA-R6-OAR-2025-0012, at * https:// www.regulations.gov * or via email to *[email protected].* 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 Mr. Emad Shahin, 214-665-6717, *[email protected].* 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.*
*Docket:* The index to the docket for this action is available electronically at *www.regulations.gov.* While all documents in the docket are listed in the index, some information may not be publicly available due to docket file size restrictions or content ( *e.g.,* CBI).
**FOR FURTHER INFORMATION CONTACT:**
For information on the revisions addressing open burning, please contact Mr. Emad Shahin, EPA Region 6 Office, Infrastructure and Ozone Section, 214-665-6717, *[email protected].* We encourage the public to submit comments via *https://www.regulations.gov.* Please call or email the contact listed above if you need alternative access to material indexed but not provided in the docket.
**SUPPLEMENTARY INFORMATION:**
Throughout this document “we,” “us,” or “our” means the EPA.
**I. Background**
Section 110 of the CAA requires states to develop air pollution regulations and control strategies to ensure that air quality meets the EPA's National Ambient Air Quality Standards (NAAQS). These ambient air quality standards are established under CAA section 109 and currently address six criteria pollutants: carbon monoxide, nitrogen dioxide, ozone, lead, particulate matter (PM), and sulfur dioxide. A SIP is a collection of regulations and documents used by a state, territory, or local air district to implement, maintain, and enforce the NAAQS, and to fulfill other requirements of the CAA. The SIP must be submitted to EPA for approval and any changes a state makes to the approved SIP also must be submitted to the EPA for approval.
In a letter dated November 22, 2024, the Secretary of Energy and Environment for the State of Oklahoma (the State) submitted a revision of the Oklahoma SIP to the EPA on November 25, 2024. In this action, we are proposing to approve into the SIP the updates to OAC Title 252 Chapter 100 Subchapter 13, Open Burning (OAC 252:100-13).
ODEQ promulgated these updates to the Oklahoma open burning regulations in compliance with the Oklahoma Administrative Procedures Act and published them in the *Oklahoma Register,* the official state publication for rulemaking actions. These updated regulations are posted in the docket for this action as part of the State's submittal.
**II. The EPA's Evaluation**
Subchapter 13 imposes requirements for controlling the open burning of refuse and other combustible materials. The changes made to the open burning rules revised the requirement for using an Air Curtain Incinerator (ACI) for certain open burning operations in the Oklahoma City and Tulsa Metropolitan Statistical Areas (MSAs). An ACI is an incineration unit, operating by forcefully projecting a curtain of air across an open integrated combustion chamber or open pit or trench, in which combustion occurs. These regulatory changes clarify the State's open burning rules and comply with Oklahoma Senate Bill 246 (2021) which revised the rules and requirements for the use of ACI for open burn operations. A summary of the updates to the open burning rules follows:
1. OAC 252:100-13-8 requires the use of ACI for land clearing operations and burning of clean wood waste and transported yard brush in non-attainment areas, areas where an ambient air quality monitor has documented a violation of the primary NAAQS, or counties with a population of greater than 500,000. The requirements for using an ACI for land clearing, burning of clean wood, and burning of transported yard brush are now only applicable to Oklahoma and Tulsa counties. Previously, all seven counties in the Oklahoma City MSA and all seven counties in Tulsa MSA were included and required the use of an ACI for open burning operations. If combustible material from land clearing operations, yard brush, clean wood waste, and clean lumber is transported for open burning, OAC 252:100-13-8.1 is modified to clarify that open burning of transported materials shall not be conducted in non-attainment areas, areas where an ambient air quality monitor has documented a violation of the primary NAAQS, or counties with a population of greater than 500,000.
2. OAC 252:100-13-7 modifies the open burning requirements for Land Clearing Operations in OAC 252:100-13-7(4)(B) and the Yard Brush disposal in 100-13-7(7) to reflect that the new requirements are in OAC 252:100-13-8, or if waste is being transported, in OAC:252:100-13-8.1.
3. OAC 252:100-13 adds 13-7(9) to specify the type of material that is allowed to be open burned, namely wood waste, and clean lumber. The type of material allowed to be open burned was previously found within the ACI provisions of 13-8.
4. OAC 252:100-13 moves requirements for the use of ACI in Subchapter 17 and NSPS to Subchapter 13, OAC 252:100-13-8(c).
ODEQ provided an analysis that the SIP revisions are not expected to cause or contribute to nonattainment and reasonable further progress, or interfere with any other applicable requirements of the CAA. ODEQ added that the updates do not change the types of activities that are allowed under the open burning rules and only revise when an ACI is required for land clearing operations and the disposal of clean wood waste and transported yard brush. Oklahoma also determined that the impact of these updated regulations on emissions of PM would be minimal. Oklahoma estimates that prescribed fire in the impacted counties only accounts for 7% of Oklahoma's PM emission because much of those emissions come from land clearing and other types of open burning, such as range management in the Flint Hills grass land. [^1]
[^1] See ODEQ 110(l) Demonstration for the Removal of the Air Curtain Incinerator requirement in land clearing operations in certain counties of the Oklahoma City and Tulsa Metropolitan Statistical Areas in OAC 252:100-13. November 2024, at 14. (Available in docket)
EPA reviewed the SIP submittal and determined that the MSAs for both Tulsa and Oklahoma City are attaining the PM NAAQS. ODEQ maintains an ambient air quality monitoring network that covers both the Oklahoma and Tulsa Counties in addition to the other counties in their broader MSAs. Prior to the updates, areas needed to be designated nonattainment or in a MSA with a population of greater than 900,000 to trigger ACI requirements. With this action, areas with monitors indicating violations of the primary NAAQS or a population greater than 500,000 will trigger ACI requirements.
The revisions to OAC 252:100-13 add clarity and consistency to the State's open burning rules. These revisions do not interfere with continued attainment of the NAAQS or any other applicable CAA requirements. We are proposing to approve these revisions to OAC 252:100-13, Subchapter 13. ODEQ analysis can be found in the docket as part of the state's submittal.
As additional information, EPA has also reviewed monitoring data from 2024 (note this monitoring data hasn't completed all quality assurance for certification) indicating that all monitors in Oklahoma are attaining the standard.
**III. Impact on Areas of Indian Country**
Following the U.S. Supreme Court decision in *McGirt* v. *Oklahoma,* 140 S. Ct. 2452 (2020), the Oklahoma Governor requested approval under Section 10211(a) of the Safe, Accountable, Flexible, Efficient Transportation Equity Act of 2005: A Legacy for Users, Public Law 109-59, 109 Stat. 1144, 1937 (August 10, 2005) (“SAFETEA”), to administer in certain areas of Indian country (as defined at 18 U.S.C. 1151) the State's environmental regulatory programs that were previously approved by the EPA for areas outside of Indian country. The State's request excluded certain areas of Indian country further described below. In addition, the State only sought approval to the extent that such approval is necessary for the State to administer a program in light of *Oklahoma Dept. of Envtl. Quality* v. *EPA,* 740 F.3d 185 (D.C. Cir. 2014). [^2]
[^2] In *ODEQ* v. *EPA,* the D.C. Circuit held that under the CAA, a state has the authority to implement a SIP in non-reservation areas of Indian country in the state, where there has been no demonstration of tribal jurisdiction. Under the D.C. Circuit's decision, the CAA does not provide authority to states to implement SIPs in Indian reservations.
The EPA approved Oklahoma's SAFETEA request to administer all the State's EPA-approved environmental regulatory programs, including the Oklahoma SIP, in the requested areas of Indian country. As requested by Oklahoma, the EPA's approval under SAFETEA does not include Indian country lands, including rights-of-way running through the same, that: (1) qualify as Indian allotments, the Indian titles to which have not been extinguished under 18 U.S.C. 1151(c); (2) are held in trust by the United States on behalf of an individual Indian or Tribe; or (3) are owned in fee by a Tribe, if the Tribe (a) acquired that fee title to such land, or an area that included such land, in accordance with a treaty with the United States to which such Tribe was a party, and (b) never allotted the land to a member or citizen of the Tribe (collectively “excluded Indian country lands”).
The EPA's approval under SAFETEA expressly provided that to the extent EPA's prior approvals of Oklahoma's environmental programs excluded Indian country, any such exclusions are superseded for the geographic areas of Indian country covered by the EPA's approval of Oklahoma's SAFETEA request. [^3] The approval also provided that future revisions or amendments to Oklahoma's approved environmental regulatory programs would extend to the covered areas of Indian country (without any further need for additional requests under SAFETEA).
[^3] EPA's prior approvals relating to Oklahoma's SIP frequently noted that the SIP was not approved to apply in areas of Indian country (except as explained in the D.C. Circuit's decision in *ODEQ* v. *EPA* ) located in the State. *See, e.g.,* 85 FR 20178, 20180 (April 10, 2020). Such prior expressed limitations are superseded by the EPA's approval of Oklahoma's SAFETEA request.
As explained in the following section, the EPA is proposing to approve revisions to the Oklahoma SIP that include revisions to OAC Title 252 Chapter 100 Subchapter 13 (OAC 252:100-13) Sections 7 and 8, which will apply throughout the state of Oklahoma. Consistent with the D.C. Circuit's decision in *ODEQ* v. *EPA* and with EPA's SAFETEA approval, these SIP revisions will apply to areas of Indian country as follows: (1) pursuant to the SAFTEA approval, the SIP revisions will apply to all areas of Indian country in the State of Oklahoma other than the excluded Indian country lands as described above; and (2) pursuant to the D.C. Circuit's decision in *ODEQ* v. *EPA,* the SIP revisions will also apply to any Indian allotments or dependent Indian communities that are located outside of any Indian reservation and over which there has been no demonstration of Tribal authority.
**IV. Proposed Action**
Based on a review and analysis of the submittal, we are proposing to approve the revisions to the Oklahoma SIP, submitted on November 25, 2024. Specifically, we are proposing to approve revisions to OAC 252:100, Subchapter 13. These revisions were made to clarify the State's open burning rules and comply with Oklahoma Senate Bill 246 (2021) which revised the rules and requirements for the use of ACI for open burn operations. We propose to find that the revisions do not change the types of activities that are allowed under the state's current open burning rules and only revise certain provisions pertaining to when an ACI can be required for land clearing operations and the burning of clean wood waste and yard brush. We are thus proposing to approve these revisions in accordance with section 110 of the Act.
**V. Incorporation by Reference**
In this action, we are proposing to include in a final rule regulatory text that includes incorporation by reference. In accordance with the requirements of 1 CFR 51.5, we are proposing to incorporate by reference revisions to the Oklahoma regulations, as described in the Proposed Action section above. We have made, and will continue to make, these documents generally available electronically through *www.regulations.gov* (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 CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 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 CAA. Accordingly, this 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 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 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.
This proposed approval of revisions to the Oklahoma SIP, specifically revisions to Oklahoma Administrative Code (OAC) Title 252 Chapter 100 Subchapter 13, Open Burning, that clarify the State's open burning rules and comply with Oklahoma Senate Bill 246 (2021) will apply, if finalized as proposed, to certain areas of Indian country throughout Oklahoma as discussed in the preamble, and therefore has Tribal implications as specified in E.O. 13175 (65 FR 67249, November 9, 2000). However, this action will neither impose substantial direct compliance costs on federally recognized Tribal governments, nor preempt Tribal law. This action will not impose substantial direct compliance costs on federally recognized Tribal governments because no actions will be required of Tribal governments. This action will also not preempt Tribal law as no Oklahoma tribe implements a regulatory program under the CAA, and thus does not have applicable or related Tribal laws. Consistent with the EPA Policy on Consultation with Indian Tribes (December 7, 2023), the EPA will offer consultation to Tribal governments that may be affected by this action and provide information about this action.
**List of Subjects in 40 CFR Part 52**
Environmental protection, Air pollution control, Incorporation by reference, Intergovernmental relations, Reporting and recordkeeping requirements, Volatile organic compounds.
**Authority:**
42 U.S.C. 7401 *et seq.*
Dated: June 26, 2025.
Walter Mason,
Regional Administrator, Region 6.