The Environmental Protection Agency granted permission to California to proceed with plans for gradually phasing out diesel trucks in favor of zero-emissions heavy vehicles, a requirement that will have major effects on the nation’s transportation system.

The EPA granted waivers to California under the Clean Air Act allowing the state to proceed with regulations for emissions from heavy vehicles.

“Under the Clean Air Act, California has long-standing authority to address pollution from cars and trucks,” EPA Administrator Michael Regan said in a press release. “Today’s announcement allows the state to take additional steps in reducing their transportation emissions through these new regulatory actions.”

The rules apply to box trucks, semitrucks, and even large pickups and will mandate that zero-emissions vehicles make up 40% to 75% of sales by 2035, depending on the class.

“We’re leading the charge to get dirty trucks and buses — the most polluting vehicles — off our streets, and other states and countries are lining up to follow our lead around the world,” Gov. Gavin Newsom (D-CA) said in a statement.

The EPA sets tailpipe emissions standards for the country, but California has the right to apply for waivers to set stricter standards under the Clean Air Act.

Other states also follow the California standards, altogether making up more than a fifth of the national market. New York, New Jersey, Washington, Oregon, Massachusetts, and Vermont have all adopted California's electric truck standards.

“With six states adopting California’s first electric trucks regulation since it was passed in 2020, some 75 million Americans are already lined up to breathe cleaner air under the Advanced Clean Trucks rule,” said Paul Cort, director of Earthjustice’s Right to Zero campaign. “Other states should take notice of today’s news and adopt this lifesaving regulation to clean up truck tailpipe pollution.”

The industry has said only a minuscule fraction of the fleet meets the rules as of now and that the infrastructure is not in place to serve massive growth of EV trucks — and that the rules will entail huge costs and disruption.

The Advanced Clean Trucks regulation from the California Air Resources Board follows a 2020 executive order from Newsom requiring 100% zero-emissions heavy-duty vehicles in California wherever feasible by 2045.

The board has already approved regulations requiring 100% of new car sales in California to be zero-emission vehicles by 2035.