Trump administration seeks to block California air quality rules
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- Trump administration seeks to join industry suit to block California truck rules
- Lawsuit challenges California’s Clean Truck Partnership and 2045 EV mandate
- Federal motion claims state standards violate preemption under federal law
The Trump administration has intensified its efforts to limit California’s ability to impose clean air standards, filing a motion in federal court to join a trucking industry lawsuit that seeks to end the state’s Clean Truck Partnership, which includes a plan to switch to battery operated heavy trucks by 2045.
The motion, which would make the federal government a plaintiff in the industry lawsuit filed Monday in federal court in Sacramento, is the latest in several actions taken by the administration to weaken California’s air quality regulations, many of which are more stringent than those imposed by the federal law and the Environmental Protection Agency.
It targets a decision by the California Air Resources Board to continue enforcing the state’s standards even after President Donald Trump signed a congressional resolution aimed at invalidating them. A similar motion was filed in a lawsuit in Illinois, and another that takes aim at regulations regarding light-duty vehicles such as automobiles was filed this week in the 9th Circuit Court of Appeals.
“In a stunning act of defiance, the State of California is attempting to use its own vehicle and engine emissions standards through a so-called ‘Clean Truck Partnership’ to ban internal-combustion engines in heavy-duty trucks, notwithstanding duly enacted federal statutes specifically providing that those regulatory standards are preempted,” the administration said in its motion.
Trump signed a congressional resolution in June revoking California’s ability to impose its own standards, which had been previously allowed under a waiver of federal rules what would otherwise have banned such state-level regulations.
However, the state continued to insist that an agreement it had reached with the trucking industry two years ago that required a reduction in emissions and a shift to electric trucks by 2045 was still enforceable. California is also challenging the congressional resolution in federal court.
The industry’s top manufacturers sued on Aug. 11, and on Thursday the Trump administration filed its motion to join the lawsuit.
The move highlights the administration’s determination to end what it sees as regulatory overreach by California and other Democratic-led states, and marks the latest in a series of lawsuits that have targeted California’s policies on immigration, rights for transgender people, environmental protection and even the price of eggs.
The motion was filed on the same day that California Governor Gavin Newsom announced a proposal to begin to redraw the state’s congressional districts to favor more Democrats in response to actions by the state of Texas to draw more Republican seats as requested by Trump. It names the Air Resources Board, the board’s executive director Steven Cliff and Newsom as defendants.
“Agreement, contract, partnership, mandate — whatever California wants to call it, this unlawful action attempts to undermine federal law,” Acting Assistant Attorney General Adam Gustafson said in a statement Friday.
In their initial lawsuit, truck manufacturers Daimler Truck North America, International Motors, Paccar, Inc., and Volvo Group North America said that they were “caught in the crossfire” between the federal government and the state of California.
California, they said, continues to insist on compliance with its stricter rules and has threatened sanctions against the companies if they do not do so. But at the same time, their lawsuit says, the U.S. Department of Justice has sent the manufacturers cease-and-desist letters ordering them to stop complying with California’s demands.
“California demands that (manufacturers) follow preempted laws; the United States maintains such laws are illegal and orders (manufacturers) to disregard them,” the lawsuit says. “This situation is not tenable.”
In its motion, the federal government laid out the timeline for its decision to join the lawsuit. On Aug. 11, the day the trucking companies filed their complaint, a congressional committee sent a letter to the Air Resources Board demanding that it comply with federal regulations, the motions says.
The next day, the U.S. Department of Justice requested consent from the trucking companies to join their lawsuit. Government lawyers met via a video conference to discuss the matter on Aug. 14 and filed their motion the same day, documents in federal court show.
CARB spokeswoman Lynda Lambert said the agency continues to believe that the federal government’s actions limiting the state’s ability to enforce its environmental regulations were illegal.
“On June 12, 2025, President Trump signed unconstitutional and illegal resolutions purporting to overturn three of U.S EPA’s decisions to grant California waivers, including its Advanced Clean Cars II, Advanced Clean Trucks, and Heavy-Duty Engine and Vehicle Omnibus regulations,” Lambert said. “CARB disputes the legality and effect of these resolutions, and they are being challenged in court.”
CARB chair Liane Randolph declined to comment on the lawsuit itself.
But she has harshly criticized the administration’s efforts to weaken California’s environmental rules.
“Despite the President’s signature, this remains an unconstitutional, illegal, and foolish attempt to undermine California’s clean air protections,” she said after Trump signed the resolution in June. The action, she said, was the latest in a series of “vindictive” moves aimed at trapping consumers into using fossil fuels.
“CARB will use every tool at its disposal to continue our critical work to clean the air and address the climate crisis,” she continued at that time. “The health and well-being of all Californians depends on it.”
A hearing on whether to allow the federal government to join the lawsuit has been set for Sept. 19 in federal court in Sacramento.
This story was originally published August 15, 2025 at 2:07 PM with the headline "Trump administration seeks to block California air quality rules."
