SUPPLEMENTARY INFORMATION:

Throughout this proposed rule, the use of “we,” “us,” or “our” is intended to refer to the EPA. We use multiple abbreviations and terms in this proposed rule. While this list may not be exhaustive, for ease of reading and for reference purposes, the EPA defines the following terms and acronyms here:

ADEQ Arizona Department of Environmental Quality

CAA Clean Air Act

CBI confidential business information

EG emission guideline

MCAQD Maricopa County Air Quality Department

MSW municipal solid waste

NSPS New Source Performance Standards

TSD Technical Support Document

Table of Contents

I. Executive Summary

A. What action is the EPA taking?

B. What is the legal authority and what are the requirements?

II. Background

III. Summary of the Plan and EPA Analysis

IV. Proposed Action

V. Incorporation by Reference

VI. Statutory and Executive Order Reviews

I. Executive Summary

A. What action is the EPA taking?

The Environmental Protection Agency (EPA) is proposing to approve a State plan submitted by the Maricopa County Air Quality Department (MCAQD) pursuant to Clean Air Act (CAA) section 111(d). This plan pertains to the regulation of landfill gas and its components from existing municipal solid waste (MSW) landfills. Maricopa's county plan was submitted in response to the EPA's promulgation of Emissions Guidelines and Compliance Times for MSW landfills.^[1]

B. What is the legal authority and what are the requirements?

The EPA is proposing to approve the MCAQD's October 4, 2022 section 111(d) plan submittal for existing MSW landfills submitted pursuant to 40 CFR part 60, subparts B and Cf. Therefore, the EPA is proposing to amend 40 CFR part 62, subpart D, to reflect this action. This approval is based on the rationale discussed below and in further detail in the Technical Support Document (TSD) associated with this action. The scope of the proposed approval of the section 111(d) plan is limited to the provisions of 40 CFR parts 60 and 62 for existing MSW landfills, as referenced in the Emission Guidelines (EGs), subpart Cf.

II. Background

CAA section 111(b)(1)(A) requires the EPA Administrator to promulgate a list of categories of stationary sources that the Administrator, “in his judgment,” finds “causes, or contributes significantly to, air pollution which may reasonably be anticipated to endanger public health or welfare.” The EPA has the authority under this section to define the scope of the source categories; to determine, consistent with the statutory requirements, the pollutants for which standards should be developed; and to distinguish among classes, types, and sizes within categories in establishing the standards.^[2] Once the EPA lists a source category that contributes significantly to dangerous air pollution, the EPA must, under CAA section 111(b)(1)(B), establish “standards of performance” for “new sources” in the source category. These standards are referred to as new source performance standards, or NSPS. The NSPS are national requirements that apply directly to the sources subject to them.

The basis for standards of performance is the “degree of emission limitation” that is “achievable” by sources in the source category by application of the “best system of emission reduction” that the EPA determines is “adequately demonstrated” (BSER). As explained further below in this section, the D.C. Circuit has explained that systems are not “adequately demonstrated” if they are “purely theoretical or experimental.” ^[3] The D.C. Circuit has stated that in determining the “best” adequately demonstrated system for the pollutants at issue, the EPA must also take into account “the amount of air pollution” reduced.^[4] The D.C. Circuit has also stated that the EPA may weigh the various factors identified in the statute and caselaw to determine the “best” system and has emphasized that ( printed page 69762) the EPA has significant discretion in weighing the factors.^[5]

After determining the BSER, the EPA sets an achievable emission limit based on application of the BSER.^[6] For a CAA section 111(b) rule, the EPA determines the standard of performance that reflects the achievable emission limit. For a CAA section 111(d) rule, the States have the obligation of establishing standards of performance for the affected sources that reflect the degree of emission limitation that the EPA has determined and provided to States as part of an emission guideline. In applying these standards to existing sources, States are permitted to take a source's remaining useful life and other factors into account.

On March 12, 1996, the EPA promulgated an NSPS applicable to certain new municipal solid waste (MSW) landfills and EGs for certain existing landfills in 40 CFR part 60, subparts WWW and Cc, respectively. These regulations were intended to control landfill gases such as non-methane organic compounds and odorous compounds.^[7] On June 17, 1997, and June 29, 1999, the Arizona Department of Environmental Quality (ADEQ) submitted a plan adopting 40 CFR 60, subpart Cc. The ADEQ's plan covered the twelve counties under its jurisdiction as well as applicable rules for the remaining three counties with their own jurisdiction over MSW landfills: Pima, Pinal, and Maricopa counties. The EPA approved the plan on September 20, 1999,^[8] and it took effect on November 19, 1999.

On August 29, 2016, the EPA finalized revisions to the MSW landfill NSPS and EGs in 40 CFR part 60, subparts XXX and Cf, respectively.^[9] The 2016 EG revision updated the control requirements and monitoring, reporting, and recordkeeping provisions for existing MSW landfills. The current MSW landfill EGs regulates landfill gas and its components from MSW landfills for which construction, reconstruction, or modification commenced on or before July 17, 2014. The deadline for States to submit a plan to the EPA to implement the EGs was May 30, 2017. On May 21, 2021, the EPA finalized the MSW landfill Federal Plan in 40 CFR part 62, subpart OOO, that applies to States that do not have an EPA-approved State plan to implement the EG. In the absence of an approved State plan, the EPA is responsible for developing, implementing, and enforcing the Federal Plan.

On October 4, 2022, the Maricopa County Air Quality Department (MCAQD) submitted to the EPA a section 111(d) plan for existing MSW landfills. The submitted section 111(d) plan was in response to the August 29, 2016, promulgation of federal NSPS and EG requirements for MSW landfills, 40 CFR part 60, subparts XXX and Cf, respectively. In addition, on July 5, 2023, the MCAQD and the EPA entered into a memorandum of agreement delegating authority to implement and enforce the Federal Plan to the MCAQD.^[10] This delegation remains in effect until the EPA approves the MCAQD's MSW landfill plan. State plan submittals and revisions under CAA section 111(d) must be consistent with the applicable EGs and the requirements of 40 CFR part 60, subpart B. These requirements include general provisions applicable to the adoption and submittal of State plans under CAA section 111(d). Additionally, State plan submittals and revisions are also subject to 40 CFR part 60, subpart A. This subpart establishes the procedural framework by which the EPA will approve or disapprove State plan submittals. Once approved by the EPA, the State plan becomes federally enforceable.

III. Summary of the Plan and EPA Analysis

The EPA has reviewed the October 4, 2022 section 111(d) plan submittal in the context of the requirements of 40 CFR part 60, subparts B and Cf, and part 62, subpart A. In this action, the EPA is proposing to determine that the submitted section 111(d) plan meets the above-cited requirements. The primary mechanism selected by the MCAQD to implement the EGs for existing MSW landfills under State jurisdiction is through incorporation by reference of 40 CFR part 60, subpart Cf, into the Maricopa County Air Pollution Control Regulations (under Regulation III—Control of Air Contaminants, Rule 321, Existing Municipal Solid Waste (MSW) Landfills), on September 28, 2022. While the MCAQD submitted the entire Rule 321, it asked that the EPA only take action on the portion of the rule applicable to the MSW EGs.^[11] A detailed explanation of the rationale behind this proposed approval is available in the TSD.

IV. Proposed Action

The EPA is proposing to approve the MCAQD's October 4, 2022 section 111(d) plan submittal for existing MSW landfills submitted pursuant to 40 CFR part 60, subparts B and Cf. Therefore, the EPA is proposing to amend 40 CFR part 62, subpart D, to reflect this action. This approval is based on the rationale discussed above and in further detail in the TSD associated with this action. The scope of the proposed approval of the section 111(d) plan is limited to the provisions of 40 CFR parts 60 and 62 for existing MSW landfills, as referenced in the EGs, subpart Cf.

V. Incorporation by Reference

In this document, the EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference of the State plan. In accordance with requirements of 1 CFR 51.5, EPA is proposing to incorporate by reference MCAQD rules regarding MSW landfills discussed in section III of this preamble. The EPA has made, and will continue to make, these materials generally available through www.regulations.gov, Docket ID No. EPA-R09-OAR-2026-5710, 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).

VI. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a CAA section 111(d) submission that complies with the provisions of the Act and applicable Federal regulations. 42 U.S.C. 7411(d); 40 CFR part 60, subparts B and Cf; and 40 CFR part 62, subpart A. Thus, in reviewing CAA section 111(d) State plan submissions, EPA's role is to approve State choices, provided that they meet the criteria of the Act and implementing regulations. Accordingly, ( printed page 69763) this 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:

A. Executive Order 12866: Regulatory Planning and Review

This action is not a significant regulatory action as defined in Executive Order 12866 (58 FR 51735, October 4, 1993) and was therefore not subject to a requirement for Executive Order 12866 review.

B. Executive Order 14192: Unleashing Prosperity Through Deregulation

This action is not an Executive Order 14192 regulatory action because this action is not significant under Executive Order 12866.

C. Paperwork Reduction Act (PRA)

This action does not impose an information collection burden under the PRA (44 U.S.C. 3501 et seq.) because it does not contain any information collection activities.

D. Regulatory Flexibility Act (RFA)

This action is certified to not have a significant economic impact on a substantial number of small entities under the RFA (5 U.S.C. 601 et seq.). This action will approve a State plan pursuant to CAA section 111(d) and will therefore have no net regulatory burden for all directly regulated small entities.

E. Unfunded Mandates Reform Act (UMRA)

This action does not contain any unfunded mandate as described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect small governments. This action imposes no enforceable duty on any State, local, or tribal governments or the private sector.

F. Executive Order 13132: Federalism

This action does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999). It will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

G. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

This action will not apply to areas of Indian country within Arizona and therefore does not have tribal implications as specified in E.O. 13175 (65 FR 67249, November 9, 2000). 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 Arizona tribe implements a regulatory program under the CAA and thus does not have applicable or related tribal laws.

H. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks

EPA interprets Executive Order 13045 (62 FR 19885, April 23, 1997) as applying only to those regulatory actions that concern environmental health or safety risks that EPA has reason to believe may disproportionately affect children, per the definitions of “covered regulatory action” in section 2-202 of the Executive Order. Therefore, this action is not subject to Executive Order 13045 because it approves a State program.

I. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution and Use

This action is not subject to Executive Order 13211 (66 FR 28355, May 22, 2001), because it is not a significant regulatory action under Executive Order 12866.

J. National Technology Transfer and Advancement Act

This rulemaking does not involve technical standards. This action 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.

Authority: 42 U.S.C. 7401 et seq.

91 FR 69761