US Congress votes to revoke EPA waivers for California heavy-duty vehicle regulations
1 May 2025
The US House of Representatives voted to revoke the waivers granted by the Environmental Protection Agency (EPA) for two California emission regulations for heavy-duty engines and vehicles:
- A waiver that permitted the California Air Resources Board (CARB) to implement the Heavy-Duty Low NOx Omnibus Regulation (House vote 225-196). The Omnibus rule requires a further 90% reduction of NOx emissions from heavy-duty onroad engines, to be phased-in over 2024-2031, and introduces a number of other requirements such as a new low load test cycle and extended emission durability periods.
- A waiver that permitted CARB to implement the Advanced Clean Trucks (ACT) rule (House vote 231-191). The ACT rule introduces a mandatory schedule for the sales of zero-emission vehicles (ZEV), which would require that 55% of new Class 2b-3 vehicles, 75% of new Class 4-8 vehicles, and 40% of new Class 7-8 tractors sold in California be ZEVs by 2035.
The two EPA waiver decisions are being repealed under the Congressional Review Act (CRA). The measures must be still passed by a simple majority in the US Senate.
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.
If the Senate votes to approve the repeal of the waivers, it will likely trigger a legal standoff between California and the federal government.
Source: US Congress