In the wake of Trump’s waiver rollback, top truck manufacturers are suing to dismantle California’s strict emissions standards—and risking a showdown over clean-air authority.

A group of truck manufacturers have filed a lawsuit against California regulators, contending that the Golden State lacks the authority to enforce its heavy-duty vehicle emissions standards, which are stricter than federal standards.

The complaint, submitted on Monday to the U.S. District Court for the Eastern District of California, maintained that truck makers should not have to comply with the state’s emissions rules, after the federal government rendered them “unlawful” in June.

Filed by Daimler Truck North America, International Motors, Paccar and Volvo Group North America, the lawsuit requested a declaratory judgement against Gov. Gavin Newsom (D) and the California Air Resources Board as well as injunctive relief.

The complainants argued that recent federal government resolutions “statutorily preempted California’s emissions standards governing heavy-duty vehicles and engines.”

“Notwithstanding that new legislation, California continues to demand compliance with its heavy-duty emissions standards,” the case stated.

The legislation, signed by President Trump in June, included three congressional resolutions that upended California’s rules on gas-fueled vehicle phaseouts.

One of the three resolutions targeted the Advanced Clean Trucks rule — a regulation aimed at  accelerating the state’s transition to less-polluting trucks that would have required 7.5 percent of these vehicles to be emissions-free by 2035.

A second was the state’s Omnibus Regulation, which aimed to slash heavy-duty nitrogen oxide emissions by 90 percent, update engine testing protocols and further extend engine warranties.