US Senate votes to repeal EPA waivers for California ACC II, ACT, Omnibus emission regulations
26 May 2025
The US Senate voted on May 22nd to revoke three waivers of preemption issued by the Environmental Protection Agency (EPA) for the California Air Resources Board (CARB):
- A waiver that permitted CARB to implement the Advanced Clean Cars II (ACC II) regulation. The ACC II package includes the zero-emission vehicle (ZEV) requirements for model year 2026 and later—which mandate that 100% of new light-duty vehicles sold in California from 2035 be ZEVs (with a 20% allowance for eligible plug-in hybrids)—as well as the LEV IV emission standards for criteria pollutants.
- A waiver that permitted CARB to implement the Advanced Clean Trucks (ACT) rule, which would introduce a mandatory schedule for the sales of ZEV Class 2b - Class 8 trucks.
- A waiver that permitted CARB to implement the Heavy-Duty Low NOx Omnibus Regulation, which would require a further 90% reduction of NOx emissions from heavy-duty onroad engines.
The three Congressional resolutions were adopted by the House of Representatives on April 30th (the heavy-duty vehicle waivers: H.J.Res.87 and H.J.Res.89) and on May 1st (ACC II waiver, H.J.Res.88). Now, after the Senate vote, the resolutions must be signed by President Trump to become law.
The EPA waiver decisions are being repealed under the Congressional Review Act (CRA). There is, however, a legal uncertainty whether Congress can overrule an EPA waiver. In March, the US Government Accountability Office (GAO) issued an opinion that the EPA waivers are not rules and therefore Congress does not have the power to revoke them under CRA.
CARB rejected the Senate vote as illegal. “California profoundly disagrees with today’s unconstitutional, illegal and foolish vote attempting to undermine critical clean air protections,” said CARB Chair Liane Randolph in a statement. “California will pursue every available remedy to challenge these actions and defend our right to protect the public from dangerous air pollution. Turning the clock back on both cleaner combustion engine requirements and zero-emission technology is an attack on clean air.”
The Senate vote was praised by the auto industry and denounced by environmental groups.
Source: US Senate