California Clean Air Act Preemption Waivers
Current understanding
Under Clean Air Act §209, California may seek EPA waivers of federal preemption to set its own motor vehicle emission standards, which other states may then adopt under §177. Congress in 2025 used the Congressional Review Act to nullify EPA waiver decisions for California’s heavy-duty vehicle emission warranty rules, Advanced Clean Trucks (ACT), zero-emission airport shuttle, and zero-emission powertrain certification programs (Public Law 119-15), reasserting federal preemption over those standards. Legal debate continues over whether individual waiver decisions constitute ‘rules’ subject to CRA review; practical effect is to block enforcement of the covered California heavy-duty ZEV mandates and the §177 adoption pathway for other states.
Evidence log
- 2025-01-13 — Preserving Choice in Vehicle Purchases Act: 2025 — Preserving Choice in Vehicle Purchases Act (introduced) would statutorily prohibit EPA from granting Clean Air Act preemption waivers for any state standards restricting sales or use of new ICE vehicles and require revocation of such waivers granted since Jan 1, 2022; unenacted but would foreclose the waiver pathway used for California’s ACC II and Advanced Clean Trucks. (novelty: 3)
- 2026-07-30 — Clean Air Act Operating Permit Program Revisions; California; Amador County Air Pollution Control District, Calaveras County Air Pollution Control District, Great Basin Unified Air Pollution Control District, Northern Sierra Air Quality Management District: cross-connection with title-v-emergency-affirmative-defense: California air-district Title V program revisions removing emergency affirmative defense provisions are a distinct California CAA action stream from the ARB motor vehicle preemption waiver disputes; both involve EPA action on California CAA program elements. (novelty: 2)
- 2026-07-23 — Providing congressional disapproval under chapter 8 of title 5, United States Code, of the rule submitted by the Environmental Protection Agency relating to “California State Motor Vehicle Pollution Control Standards; Notice of Decision Granting a Waiver of Clean Air Act Preemption for California’s Advanced Clean Car Program and a Within the Scope Confirmation for California’s Zero Emission Vehicle Amendments for 2017 and Earlier Model Years”.: cross-connection with emissions-standards: H.J.Res. 205 is another CRA disapproval targeting a specific California Clean Air Act preemption waiver (Advanced Clean Car / ZEV pre-2017), directly linking the general emissions-standards page with the California waivers sub-topic. (novelty: 2)
- 2026-07-18 — Providing congressional disapproval under chapter 8 of title 5, United States Code, of the rule submitted by the Environmental Protection Agency relating to “California State Motor Vehicle Pollution Control Standards; Notice of Decision Granting a Waiver of Clean Air Act Preemption for California’s 2009 and Subsequent Model Year Greenhouse Gas Emission Standards for New Motor Vehicles”.: 2025 — CRA joint resolution introduced targeting EPA’s waiver for California’s 2009 and subsequent model-year GHG emission standards for new motor vehicles, extending the CRA-based rollback pattern (previously applied to the heavy-duty ACT/warranty waivers under P.L. 119-15) to the light-duty GHG waiver. (novelty: 2)
- 2025-06-12 — Providing congressional disapproval under chapter 8 of title 5, United States Code, of the rule submitted by the Environmental Protection Agency relating to “California State Motor Vehicle and Engine Pollution Control Standards; Heavy-Duty Vehicle and Engine Emission Warranty and Maintenance Provisions; Advanced Clean Trucks; Zero Emission Airport Shuttle; Zero-Emission Power Train Certification; Waiver of Preemption; Notice of Decision”.: cross-connection with emissions-standards: California §209 waivers function as a parallel track to federal EPA emission standards, letting a state set stricter vehicle rules that other states may adopt; CRA disapproval of the waivers removes that pathway for the covered heavy-duty and ZEV programs. (novelty: 3)