CAA Section 110(l) Demonstration for Adoption of NC NOx SIP Call Rules into and Removal of Clean Air Interstate Rules (CAIR) from the NC SIP

Supplement - October 26, 2026

On October 26, 2026, the Division of Air Quality (DAQ) submitted to EPA a supplement to provide correction to the April 23, 2025, Clean Air Act (CAA) Section 110(l) Noninterference Demonstration for Adoption of revisions to 15A NCAC 02D .1400 NOx Rules into, and Removal of 15A NCAC 02D .2400 CAIR from, the North Carolina State Implementation Plan (SIP) for electricity generating Units (EGUs) and Large Non-EGUs. Specifically, the correction provides the emissions from two EGUs that should have been included in the inventory of EGUs subject to the NOx SIP Call, in Table 4-2 and Figure 4-2 of the demonstration. The revised table and figure show that the inclusion of the two combustion turbines has not caused the State to exceed the statewide NOx SIP Call ozone season budget of 31,212 tons for EGUs, and even with the inclusion of the two additional EGUs, the State's 2025 ozone season NOx emissions from the EGUs were only 36% of the statewide budget. The inclusion of these two combustion turbine units does not interfere with the State’s ongoing attainment or maintenance of the NAAQS, and this error correction does not substantively alter the remainder of the 110(l) noninterference discussion submitted on April 23, 2025, including the conclusions therein. The error correction supplement can be found at: Supplement to Provide Correction to NOx SIP Call 110(l).

Final – April 23, 2025

On April 23, 2025, the Division of Air Quality (DAQ) submitted the final Clean Air Act (CAA) Section 110(l) Noninterference Demonstration for Adoption of revisions to 15A NCAC 02D .1400 NOx Rules into, and Removal of 15A NCAC 02D .2400 CAIR from, the North Carolina State Implementation Plan (SIP) for electricity generating Units (EGUs) and Large Non-EGUs, for approval by the U.S. Environmental Protection Agency (EPA).

The DAQ is proposing to revise its CAA Section 110 SIP for EGUs and large non-EGUs to (1) incorporate ground-level ozone season (May 1 – September 30) NOx SIP Call statewide budgets and reporting requirements, and (2) remove the CAIR because they no longer apply in North Carolina. Specifically, the DAQ is requesting that the U.S. EPA review and approve the following:

• Adopt revisions to two existing rules (Title 15A of the North Carolina Administrative Code (15A NCAC) 02D .1401, Definitions, and 15A NCAC 02D .1402, Applicability) in the SIP to define the EGUs and large non-EGUs subject to 15A NCAC 02D .1424 and 15A NCAC 02D .1425.
• Adopt new rule 15A NCAC 02D .1425, NOx SIP Call Budget, into the SIP to (1) incorporate the statewide ozone season NOx emission budgets for EGUs and large non-EGUs, which originate from the Section 126 Rule promulgated by EPA in parallel with the NOx SIP Call; and (2) specify reporting requirements to evaluate compliance with the statewide ozone season budgets.
• Adopt new rule 15A NCAC 02D .1424, Large Non-Electric Generating Units, into the SIP to provide an option for large non-EGUs subject to the NOx SIP Call and former CAIR to use monitoring procedures other than continuous emissions monitoring systems (CEMS) to measure NOx emissions.
• Remove 15A NCAC 02D .2400, CAIR from the SIP.

Link to the final complete DEQ Submittal: CAA Section 110(l) Noninterference Demonstration for Adoption of NOx SIP Call Rules into, and Removal of CAIR from, the North Carolina SIP for EGUs

The complete submittal contains the following:

• Transmittal Letter
• Enclosure 1:  CAA Section 110(l) noninterference demonstration.
• Enclosure 2:  A clean copy and markup copy of revisions to North Carolina’s 15A NCAC 02D .1400 NOx SIP Call Rules and supporting hearing record.
• Enclosure 3:  A strikeout copy of the CAIR (15A NCAC 02D .2401 through .2413) in the North Carolina SIP.