Ozone Reclassification SIP Requirements
Current understanding
When an ozone nonattainment area is reclassified (“bumped up”) to a higher classification under Clean Air Act Section 181, the area must submit additional SIP elements under CAA Section 182. EPA’s interpretation of which Section 182 obligations apply upon reclassification has shifted: a January 2025 final rule took one approach, and a subsequent proposed rule would limit obligations to those Section 182 requirements specific to the area’s current (post-reclassification) classification, rather than layering on requirements from prior classifications. Practical effect turns on which control measures (e.g., RACT, contingency measures, offsets) states must adopt after a bump-up.
Evidence log
- 2026-05-29 — Designation of Areas for Air Quality Planning Purposes; Michigan; Technical Amendment: cross-connection with ozone-naaqs-area-designations: Detroit’s court-ordered reclassification to Moderate nonattainment triggers the Section 182 SIP obligations addressed by the ozone reclassification SIP requirements rulemaking. (novelty: 2)
- 2026-06-04 — Conditional Approval; Contingency Measure State Implementation Plan for the 2008 Ozone Standards; San Joaquin Valley, California: cross-connection with ozone-naaqs-area-designations: Contingency measure SIP obligations under CAA Section 182 are directly implicated in both nonattainment area planning and the pending reclassification rule that would narrow which classification’s requirements apply. (novelty: 2)
- 2026-06-11 — Attainment Date Extension for the South Coast, California 2012 Annual PM2.5 Fine Particulate Matter Nonattainment Area: cross-connection with pm25-naaqs-nonattainment-areas: Both concern Clean Air Act nonattainment area classifications and the SIP/deadline consequences when statutory attainment dates cannot be met. (novelty: 2)
- 2026-06-12 — Ozone Reclassification State Implementation Plan Rule: cross-connection with ozone-naaqs-area-designations: Reclassification triggers determine which Section 182 SIP obligations attach to a designated nonattainment area. (novelty: 3)