The U.S. Supreme Court announced today that it will not review challenges to California’s core statutory authority to enforce its own pollution limits for new cars and passenger trucks. In a short, unsigned order, the Court declined to consider oil and gas interests’ challenge to the lawfulness of EPA’s decision granting California a waiver from Clean Air Act preemption for its clean vehicle standards.

The Court’s order does grant review on the narrow, threshold question concerning whether Petitioners had standing to bring their claims. Today’s order does not address the separate petition filed by state challengers raising the unprecedented constitutional claim that section 209 of the Clean Air Act violated the “equal sovereignty” doctrine.

“California’s clean car standards have successfully helped reduce the dangerous soot, smog, and climate pollution that put all people at risk, while also turbocharging job creation and a strong economy,” said Alice Henderson, Director and Lead Counsel for Transportation and Air for Environmental Defense Fund. “EPA’s decision to grant California this preemption waiver is based on a rock-solid legal foundation and decades of precedent, and it ensures vital clean air protections for millions of people.”

California's emissions standards have played a central role in many life-saving advancements in vehicle emission technology, from catalytic converters to zero-emission vehicles. Congress has long recognized California’s leadership in addressing the harmful pollution from new vehicles and adopted Clean Air Act provisions specifically excluding California’s standards from preemption.

Since 1967, the Clean Air Act has contained a preemption waiver for California’s emission standards for new motor vehicles, so long as those standards are at least as protective as national standards. In that time EPA has granted California more than 75 waivers. The California clean cars program at issue in this case has been adopted by 17 other states across the country.

In 2023, the oil and gas industry as well as the Attorneys General of Ohio and other states challenged this most recent waiver. The state challengers were not seeking their own right to set standards – they just wanted to disrupt California’s clean cars program by challenging the waiver guaranteed by federal law.

In April 2024, a unanimous panel of judges on the U.S. Court of Appeals for the D.C. ruled against the challengers and upheld EPA’s decision to grant the waiver to California. EDF was part of a coalition of environmental and health groups that helped defend the California waiver as parties in that case. California, joined by 18 other states and the District of Columbia, and a group of major auto manufacturers including Ford and Honda, also intervened to defend EPA's decision.

The challengers then filed petitions with the Supreme Court asking it to review the D.C. Circuit's decision. Today, the Court denied the oil and gas interests’ petition seeking review of the lawfulness of EPA’s decision to grant California the waiver. The Court did grant review limited to the narrow question about challengers standing to bring their claims.

“EDF is committed to continuing to help defend California’s Clean Air Act authority and the life-saving clean car standards under attack in these challenges,” said Henderson.