WASHINGTON - U.S. Environmental Protection Agency (EPA) is proposing to disapprove of California's Heavy-Duty (HD) Inspection and Maintenance (I/M) Requirements as it applies to out-of-state and out-of-country vehicles. The HD I/M requirement in the State Implementation Plan (SIP) submitted by California establishes an I/M program for any heavy-duty vehicle driven in the state -- regardless of registration. EPA is proposing to deny these actions due to concerns that this requirement violates the U.S. Constitution's Commerce Clause and this inconsistency with Federal law also violates Section 110 of the Clean Air Act.

"California was not, and has never been, duly elected by the American people to run our great country," said EPA Administrator Lee Zeldin. "The state's power grab knows no bounds. EPA will not allow California to violate federal law, and we will not sit idly by while, in the name of climate change, they raise the cost of living on all Americans who rely on truck drivers and the products they deliver across the country."

Furthermore, by seeking to apply California's HD I/M requirement to foreign vehicles, California's SIP appears to ignore the fundamental principal that powers related to foreign affairs are solely vested by the Federal government.

EPA will not allow California to violate federal law in a manner that foists yet another attack on truck drivers and engine manufacturers who provide the food and products we need to survive. California's approach appears to be part of a larger strategy to drive out affordable trucks and products based on an extreme climate ideology.

EPA's proposed partial disapproval and partial approval will be open for public comment for 30 days after publication in the Federal Register, and EPA will consider all comments submitted before taking final action on the proposal.

Background

This proposed disapproval comes on the heels of two complaints filed by the U.S. Department of Justice in federal courts against the California Air Resources Board (CARB) regarding the State's enforcement of preempted emissions standards through its so-called "Clean Truck Partnership" with heavy-duty truck and engine manufacturers.

In February, Administrator Zeldin announced alongside President Trump and the newly created National Energy Dominance Council, that EPA would transmit to Congress three waiver rules granted by the Biden EPA - California's Advanced Clean Cars II, Advanced Clean Trucks, and Heavy-Duty Engine Omnibus NOx in order to comply with the agency's duties under the Congressional Review Act (CRA). In June 2025, the three CRA resolutions disapproving California's vehicle emission waivers were signed into law following passage in the U.S. House of Representatives and U.S. Senate.

These waivers would have raised costs, restricted consumer choice, and strained the electric grid. By passing the CRA resolutions of disapproval, Congress rejected these mandates and reaffirmed the importance of maintaining a consistent national approach to vehicle standards rather than allowing a single state to impose its radical agenda on the rest of the country.

EPA Takes Action to Deny California's Latest Illegal Power Grab on Heavy-Duty Vehicles | US EPA