02/03/2026
The U.S. Environmental Protection Agency has issued a final disapproval of a California heavy-duty vehicle emissions inspection rule as it applies to trucks registered outside the state, saying the rule would violate federal law and the U.S. Constitution’s Commerce Clause. 
Under the decision, California’s Heavy-Duty Inspection and Maintenance (HD I/M) regulation, also known as the Clean Truck Check, will remain enforceable only for vehicles registered in the state, but won’t be applied to out-of-state or out-of-country trucks passing through California. 
EPA Administrator Lee Zeldin emphasized that while California may enforce emissions requirements for in-state vehicles, the federal government will not allow the state to impose unnecessary regulations on the entire nation. He warned that extending such rules to out-of-state trucks could drive up costs for truckers and businesses and interfere with interstate commerce. 
The move marks a significant clash between federal regulators and California’s environmental policies, which have historically set aggressive emissions standards. California officials have indicated they may continue enforcement at the state level despite the EPA’s disapproval. 
Source: EPA Press Office / Federal Register action (via EPA.gov)
Website of the U.S. Environmental Protection Agency (EPA). EPA's mission is to protect human health and the environment.
