EPA on Tuesday limited California’s Clean Truck Check to vehicles registered in the state, blocking a broader rule that would have required emissions inspections for out‑of‑state heavy trucks. The agency said extending inspections to trucks from other states or countries would improperly shift compliance costs and raise constitutional and Clean Air Act problems. CARB disputes the decision, arguing out‑of‑state trucks are a major contributor to NOx pollution in California. The final rule was signed by acting EPA Region 9 Administrator Michael Martucci and will appear soon in the Federal Register.
EPA Blocks California From Requiring Emissions Inspections For Out‑Of‑State Heavy Trucks
The U.S. Environmental Protection Agency on Tuesday refused to allow California to extend its heavy‑duty vehicle inspection and maintenance program to trucks registered in other U.S. states, Mexico or Canada. The agency approved California’s Clean Truck Check only as applied to vehicles registered in the state, saying inspections of out‑of‑state vehicles would improperly shift the costs of compliance beyond California’s borders.
Background
In 2021, the California Air Resources Board (CARB) adopted the Clean Truck Check rule, strengthening inspection and maintenance requirements for heavy‑duty trucks to reduce nitrogen oxides (NOx), a key smog precursor. California’s major ports and cross‑border freight flows mean a large share of heavy‑duty traffic in the state is driven by vehicles registered elsewhere. CARB estimated that out‑of‑state trucks contribute as much as 30% of the state’s heavy‑duty NOx emissions.
EPA Decision And Rationale
EPA’s final decision approves the Clean Truck Check only for trucks registered in California. Agency officials concluded that applying the rule to vehicles registered in other states or in Mexico and Canada would amount to outsourcing California’s attainment obligations and would impose costs on parties outside the state—raising constitutional and Clean Air Act concerns.
"The Trump EPA will never back down from holding California accountable and stopping them from imposing unnecessary regulations on the entire nation," Administrator Lee Zeldin said in a statement accompanying the decision.
In its written decision, EPA said critics were misreading the agency’s earlier press release and defended the legal and factual basis for narrowing approval. CARB had argued the agency’s press‑release language was "gratuitous and prejudicial" and that California had addressed the constitutional concerns. EPA rejected CARB’s claim that the agency’s motives were pretextual.
CARB Response
CARB pushed back on the limited approval, saying California’s heavy‑duty pollution problem is driven in part by out‑of‑state traffic and that inspections of visiting vehicles are necessary to protect local air quality. The state also contended it had remedied the constitutional issues EPA raised, but the agency maintained that the statute and constitutional principles restrict California from compelling compliance by vehicles registered in other jurisdictions.
What Happens Next
The final rule was signed by acting EPA Region 9 Administrator Michael Martucci and will be published soon in the Federal Register. Publication will finalize the agency’s decision and put its legal reasoning on the public record; California officials may consider administrative or legal options in response.
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