Senate Republicans have voted 51 to 44 to overturn a waiver that allowed California to set stricter air pollution standards for vehicles. The state has received waivers more than 100 times since federal laws granted the right some 50 years ago.

Sixteen other states and the District of Columbia follow California’s emissions standards, and most of them have implemented fossil fuel vehicle phase outs. Other Senate votes today repealed waivers for that allowed California to set stricter emissions standards for medium- and heavy-duty vehicles.

California’s so-called EV mandate is actually a zero-emissions standard. Beginning in 2026, the state was to begin requiring increasing sales of zero-emissions cars and passenger trucks until 2035, when automakers would have to sell only zero-emissions vehicles. 

Currently, two technologies qualify: hydrogen fuel cells and battery electric vehicles. Given the growing pains that fuel cells and hydrogen filling networks have been experiencing, EVs quickly became the de facto approach to meeting California’s 2035 deadline.

Last year, 25.3% of new light-duty vehicles in California qualified as zero emissions, and nearly all of them were EVs. The state’s mandate required 35% of new sales to be ZEV in 2026, something automakers have said would be “impossible.” 

ZEV sales growth in California was flat in 2024, though previous years were different, with share rising from 7.8% in 2020 to 25% in 2023.

The vote on Thursday bucked precedence by going against the advice of the Senate parliamentarian and the Government Accountability Office, which both had ruled that the waiver could not be revoked under the Congressional Review Act. The CRA allows a simple majority vote on a resolution to overturn a regulation, allowing a Senate vote to proceed without threat of filibuster.

Previously, California’s attorney general Rob Bonta was “prepared for” Republican efforts to repeal the emissions waiver via the CRA. “We don’t think it’s an appropriate use of the Congressional Review Act, and we’re prepared to defend ourselves if it’s wrongfully weaponized,” he told Politico in early March.