What you need to know:
- EPA partially approves California's HD I/M program for in-state trucks only.
- Out-of-state and foreign vehicles excluded due to Clean Air Act and Commerce Clause concerns.
- Clean Truck Check requires emissions testing and maintenance for heavy-duty trucks.
- CARB continues state enforcement for all trucks operating in California.
The EPA issued a split decision last week on California's Heavy-Duty Inspection and Maintenance (HD I/M) program, allowing enforcement for California-registered trucks while blocking its application to vehicles registered elsewhere.
In a final rule issued on January 27, the EPA concluded that the Golden State could not legally apply its heavy-duty inspection program to trucks solely passing through the state, restricting federal approval to vehicles registered in California.
[Related: US retreats from CAFE rules in big fuel economy policy shift]
"The Trump EPA will never back down from holding California accountable and stopping them from imposing unnecessary regulations on the entire nation. If California had its way, prices would skyrocket for truckers and businesses across America. Affordable trucks are vital for keeping food and goods moving and prices low for families," said EPA Administrator Lee Zeldin. "Americans didn't vote for California's policies to be imposed nationwide. They voted for President Trump's policies that put working families first."
The decision follows California's submission of a revised State Implementation Plan seeking to extend inspection and maintenance requirements to all non-gasoline heavy-duty vehicles over 14,000 pounds operating in the state.
The EPA determined that applying the rule to out-of-state and foreign-registered vehicles raised legal issues, including potential conflicts with the Commerce Clause and federal authority over foreign affairs, and concluded that California failed to provide the required assurances under the Clean Air Act. As a result, the agency partially disapproved the SIP revision for those vehicles.
[Related: EPA won't delay 2027 NOx rule, but plans 'major changes']
At issue is California's Clean Truck Check program, a heavy-duty inspection and maintenance regulation adopted under state law to ensure proper operation of emissions controls on large trucks. Senate Bill 210 required CARB to establish the program and phase in its implementation beginning in 2023.
Clean Truck Check uses testing and emissions monitoring to find trucks that need repairs and make sure they get fixed. The program applies to large diesel and alternative-fuel vehicles driving on California roads, even if they’re registered in another state. The EPA's partial approval makes only the in-state portion of the rule federally enforceable under the Clean Air Act. The agency added that no federal sanctions will apply because the SIP submission was voluntary.
[Related: OEMs win first round of CARB's Clean Truck lawsuit]
California wasted no time criticizing the EPA's decision.
"Today's announcement is a whole lot of bluster about bean counting," CARB spokesperson Lindsay Buckley said in a statement to the media. "EPA has no authority over this program, and we will continue to enforce the law to ensure that all trucks coming into and operating in California abide by the same rules—even if EPA doesn't want to give us credit."
