Air Quality State Implementation Plans; Approvals and Promulgations: North Carolina; Sulfur Dioxide Emissions from Combustion Sources

Air Plan Approval; North Carolina; Revisions to Regulations for Sulfur Dioxide Emissions From Combustion Sources

SUPPLEMENTARY INFORMATION:

I. This Action

EPA is approving a SIP revision submitted by the NCDEQ, on November 28, 2023, that revises Rule 15A North Carolina Administrative Code (NCAC) 02D .0516, Sulfur Dioxide Emissions from Combustion Sources. Rule 02D .0516 requires sources emitting SO ₂ through combustion and discharging through a vent, stack, or chimney to comply with an emission standard of 2.3 pounds per million British thermal unit (lbs/MMBtu). The Rule also provides criteria for how affected sources should determine compliance with the emission standard. North Carolina's November 28, 2023, SIP revision seeks to modify the Rule 02D .0516 applicability criteria respecting control devices and the provisions for determining compliance with the SO ₂ emission standard. More specifically, the SIP revision seeks to provide clarity and consistency with North Carolina's position that the use of supplemental fuels in combustion units beyond what is needed for proper operation is not a means for compliance with the SO ₂ emission standard at Rule 02D .0516.

II. Background

Through a notice of proposed rulemaking (NPRM) published on August 14, 2025, (90 FR 39142), EPA proposed to approve North Carolina's November 28, 2023, SIP revision, changing Rule 02D .0516 to provide clarity and consistency with the State's position that the use of supplemental fuels in combustion units beyond what is needed for proper operation is not a means for compliance with the 2.3 lbs/MMBtu SO ₂ emission standard at Rule 02D .0516. The details of the North Carolina's submission and the rationale for EPA approving these changes are explained in the August 14, 2025, NPRM. Comments on the August 14, 2025, NPRM were due on or before September 15, 2025. EPA received three comments on the action: two in support and one potentially adverse. The comments are posted to the docket for this rulemaking. EPA summarizes and responds to the potentially adverse comment below.

III. Response to Comments

EPA addresses the potentially adverse comment below.

The commenter poses questions to EPA about EPA's proposed action. First, the commenter asks whether the SIP revision "meaningfully aligns with the latest climate science and the National Climate Assessment's projections for the Southeast, particularly regarding cumulative ozone and particulate matter exposures under increasing heat and wildfire events." This comment is not relevant to this action on the North Carolina SIP. North Carolina's Rule 02D .0516 does not relate to wildfires, and the commenter does not provide any specificity about how their concerns with cumulative ozone and particulate matter in the Southeast relate to this SIP revision. As noted in the August 14, 2025, notice of proposed rulemaking (NPRM), the changes to North Carolina's SIP clarify and add to the existing emission limits and requirements regulating SO ₂ from fuel combustion sources, so there are no increases in emissions as a result of this change.

Next, the commenter asks "[g]iven that environmental justice communities in the region often face disproportionate cumulative pollution burdens," whether EPA will "require quantifiable distributional impact analysis to ensure the SIP does not perpetuate or exacerbate inequities in air quality outcomes." This comment is not relevant to this action on the North Carolina SIP. No emissions will increase as a result of the changes to the SIP, and the commenter does not provide any information to indicate that there are any "inequalities in air quality outcomes" as a result of North Carolina's changes to Rule 02D .0516.

The commenter goes on to ask how "the proposed revision [will] ensure enforceable emissions reductions from both stationary and mobile sources, with provisions to prevent backsliding if industrial activity increases or if economic growth outpaces existing control measures." First, Rule 02D .0516 does not regulate mobile sources. Nor does the commenter provide any information to indicate that the SIP revision does not provide for enforceable emission reductions from stationary sources. As explained in the August 14, 2025, NPRM, the approved SIP regulates SO ₂ emissions from fuel combustion sources, and the SIP revision would help to provide clarity and consistency with the State's position that the use of supplemental fuel beyond what is needed for proper operation of a combustion unit is not a means for determining compliance with the SO ₂ emission limit.

The commenter then asks whether EPA has "considered co-benefits of integrating stricter SIP measures with climate mitigation strategies-such as accelerating electrification of transport and industrial processes-to improve both public health and greenhouse gas reductions." This comment is not relevant to this action on the North Carolina SIP.

Next, the commenter asks "[w]hat mechanisms will be in place to guarantee transparent, publicly accessible monitoring data, particularly in rural and low-income areas where regulatory air quality sensors are sparse, but health vulnerabilities are often high." This comment is not relevant to this action on the North Carolina SIP. Generally, state and local air agencies are required to maintain an ambient air monitoring network consistent with regulations in 40 CFR part 58, and the state and local agencies go through a public participation process in establishing their federally approved monitoring networks.

The commenter then asks whether the SIP revision will "include adaptive management protocols to quickly respond to emerging air pollution sources, such as industrial expansions, port traffic increases, or climate-exacerbated wildfire smoke transport, without requiring multi-year procedural delays." This comment is not relevant to the changes being made to North Carolina's SIP.

Finally, the commenter asks whether "[c]onsidering the economic costs of air pollution-related health impacts" the "cost-benefit analysis incorporated updated public health valuation methods that capture the full societal benefits of stronger controls, especially for children, seniors, and outdoor workers." This comment is not relevant to this action on the North Carolina SIP. There is no such cost-benefit analysis in the August 15, 2025, NPRM, and as noted therein, and above in this action, the changes to Rule 02D .0516 will not result in emissions increases.

IV. Incorporation by Reference

In this document, EPA is finalizing regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, and as discussed in Sections I and II of this preamble, EPA is finalizing the incorporation by reference of North Carolina Rule 15A NCAC 02D .0516, Sulfur Dioxide Emissions from Combustion Sources, state effective June 1, 2023. EPA has made, and will continue to make, these materials generally available through www.regulations.gov and at the EPA Region 4 Office (please contact the person identified in the For Further Information Contact section of this preamble for more information). Therefore, these materials have been approved by EPA for inclusion in the State implementation plan, have been incorporated by reference by EPA into that plan, are fully federally enforceable under sections 110 and 113 of the CAA as of the effective date of the final rulemaking of EPA's approval, and will be incorporated by reference in the next update to the SIP compilation. ⁽¹⁾

V. Final Action

EPA is approving North Carolina's November 28, 2023, SIP revision consisting of changes to Rule 15A NCAC 02D .0516, Sulfur Dioxide Emissions from Combustion Sources, state effective June 1, 2023, for the reasons discussed above.

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. 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 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 CAA.

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).

This action is subject to the Congressional Review Act, and EPA will submit a rule report to each House of the Congress and to the Comptroller General of the United States. This action is not a "major rule" as defined by 5 U.S.C. 804(2).

Under section 307(b)(1) of the CAA, petitions for judicial review of this action must be filed in the United States Court of Appeals for the appropriate circuit by December 1, 2025. Filing a petition for reconsideration by the Administrator of this final rule does not affect the finality of this action for the purposes of judicial review nor does it extend the time within which a petition for judicial review may be filed, and shall not postpone the effectiveness of such rule or action. This action may not be challenged later in proceedings to enforce its requirements. See section 307(b)(2).

For the reasons stated in the preamble, EPA amends 40 CFR part 52 as follows:

PART 52-APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

Subpart II-North Carolina

⁽¹⁾ See 62 FR 27968 (May 22, 1997).