US EPA sends four California waivers to Congress for potential repeal
15 June 2026
The US Environmental Protection Agency (EPA) transmitted four California waiver rules to Congress for review and potential reversal. The waivers have given the state the authority to enact its own emission standards, which are more stringent than the federal emission regulations.
The EPA is arguing that each of the four waivers for the California Air Resources Board’s (CARB) emission regulations—approved under prior Democratic administrations—should have been sent to Congress under the Congressional Review Act (CRA). Because previous administrations have not sent the rules to lawmakers, “Congress has not been provided with its statutorily required opportunity to review these rules.”
The four rules have prospective, national effects, giving California and the states that adopted the waivers under Clean Air Act section 177 the force of federal law, supplanting EPA authority, the agency said in a press release.
The waiver rules transmitted to Congress include:
- Motor Vehicle Evaporative Emissions and Greenhouse Gas (Advanced Clean Cars I, ACC I)—This rule imposes vehicle emission requirements stricter than federal standards, which has resulted in a push towards electric vehicles across the nation.
- Reinstatement of ACC I—Following the Trump administration revoking ACC I, the Biden EPA reinstated it in 2022, allowing CARB once again to impose vehicle emission requirements higher than federal standards.
- Small Offroad Engine (SORE) Amendments—This rule imposes emission requirements for lawn and garden equipment that have resulted in the push towards electrification of these tools.
- Greenhouse Gas Emission Standards – 2009 and Subsequent Model Years—This rule allows California to enforce strict GHG standards, forcing automakers to make a vehicle fit California’s standards instead of the federal standards, while “consumers pay for this through higher vehicle costs.”
The EPA action follows a reversal by Congress of three California waivers last year. In April and May 2025, Congress voted to repeal the waivers under the Congressional Review Act. The three waivers included:
- A waiver that permitted CARB to implement the Advanced Clean Cars II (ACC II) regulation that included the zero-emission vehicle (ZEV) requirements for model year 2026 and later (which mandated that 100% of new light-duty vehicles sold in California from 2035 be ZEVs), as well as LEV IV emission standards for criteria pollutants.
- A waiver that permitted CARB to implement the Advanced Clean Trucks (ACT) rule that introduced a mandatory schedule for the sales of zero-emission trucks in California.
- A waiver that permitted CARB to implement the Heavy-Duty Low NOx Omnibus Regulation. The Omnibus rule required a further 90% reduction of NOx emissions from heavy-duty onroad engines, to be phased-in over 2024-2031.
In January 2025, CARB voluntarily withdrew two requests for EPA waivers, including waivers for the Advanced Clean Fleets (ACF) rule and the In-Use Locomotive Regulation.
Source: US EPA