(The Center Square) – California Gov. Gavin Newsom is in the nation’s capital seeking federal waivers for eight of California’s emissions policies. Without the Republican-opposed waivers, California could be unable to enforce its multi-state emissions policies that are more strict than the federal standard.

The United States Clean Air Act authorizes California to set and enforce emissions standards more strict than the federal standard, so long as the Environmental Protection Agency grants the state a waiver for each new standard. The first Trump administration attempted to revoke California’s EPA waivers, a move that was held up in court and never definitively ruled on.

“There is no Clean Air Act process for revoking a waiver – which makes sense because governments and industry rely on waivers for years after they are granted to deliver clean vehicles and develop clean air plans,” argued the California Air Resources Board, the state’s emissions regulator, at the time. “This system works, and there is no ‘off switch.’”

California’s emissions standards have been adopted by states covering nearly half of America’s new light-duty vehicles and over a quarter of new heavy-duty vehicles, meaning the waivers – or their denial – could have a major impact on national transportation.

“California’s zero-emissions truck mandate is a draconian policy that will disrupt supply chains, increase prices, and put our economy at risk,” said Congressman Jay Obernolte, R-California, on X. “The EPA should reject this waiver to protect jobs and ensure practical solutions”

Due to California serving as the main port of entry for sea-borne Pacific trade and as a major thoroughfare for trade between the United States and Mexico, California heavy-duty transportation standards would have a significant effect on the entire American supply chain.

States covering 40% of new light-duty vehicles and 26% of new heavy duty vehicles have voluntarily adopted California’s emission standards. Most of the multi-state standards fall under policies that have not yet been granted an EPA waiver, leaving their futures in jeopardy.

The two main multi-state rules are the Advanced Clean Cars II and Advanced Clean Fleets rules, which each require rapid adoption of zero-emissions vehicles for passenger and heavy duty on-road transportation.

Additional California rules under EPA waiver consideration are a ban on gas-powered yard equipment and a requirement that ships in California ports use emissions filters the Coast Guard said it would not enforce due to their propensity to ignite major fires. Other rules include separate phase-outs of diesel-powered trains, diesel-powered refrigeration in cargo trucks, some diesel-powered agricultural and construction equipment, and new heavy duty vehicle standards.

If the Biden administration approves the waivers, Congress still has the authority to review the waivers within 60 legislative days. With Republicans set to retake the Senate and maintain control of the House, Newsom may have already waited too long to aggressively push for the EPA waivers.