For years, California has exercised enormous influence over what aftermarket automotive parts could legally be sold across much of the country.
The Environmental Protection Agency is now signaling that the balance of power may be shifting.
In an advisory opinion released July 1, the EPA announced that manufacturers can demonstrate compliance with the federal Clean Air Act through the Specialty Equipment Market Association’s (SEMA) Certified-Emissions program instead of first obtaining approval through the California Air Resources Board (CARB).
The change creates a new federal pathway for companies seeking to sell emissions-related aftermarket parts in the other 49 states, reducing their reliance on California’s certification process.
“Americans should not be forced to solely rely on California to certify aftermarket products,” EPA Administrator Lee Zeldin said in announcing the decision. “Starting today, Americans can trust that products certified by SEMA meet federal requirements and can be used to repair vehicles.”
The aftermarket industry has long argued that California’s approval process can be expensive, time-consuming, and effectively allows one state to shape products sold throughout the country.
Under the EPA’s guidance, manufacturers can instead rely on SEMA’s certification program, provided they can demonstrate that their products do not adversely affect vehicle emissions and satisfy the agency’s compliance requirements under the Clean Air Act.
In a July 1 letter to SEMA President and CEO Mike Spagnola, EPA Assistant Administrator Jeffrey Hall explained that the agency’s longstanding Tampering Policy already provides a framework for proving emissions compliance.
“The Tampering Policy explains how a person may demonstrate that an aftermarket product does not adversely affect automotive emissions by documenting that an appropriate vehicle equipped with the product will pass the same emissions tests used by the original equipment manufacturer to certify the vehicle under the Clean Air Act,” Hall wrote.
SEMA says its Certified-Emissions program follows testing procedures comparable to those required by CARB when issuing Executive Orders approving aftermarket emissions products.
The announcement is also another example of the Trump administration’s broader effort to reduce California’s influence over national vehicle policy.
“President Trump’s commitment to reviving the American auto industry has been unwavering and has already yielded hundreds of billions in new investments, supported American jobs and expanded consumer choice,” Zeldin said. “With the aftermarket sector being a key piece of the industry, EPA is proud to deliver on the president’s agenda for the small businesses producing aftermarket parts and on behalf of the Americans who purchase those parts.”
Industry leaders welcomed the decision almost immediately.
Holley, a major manufacturer of performance automotive equipment, called the move an important step toward providing manufacturers with greater regulatory certainty.
“Holley is grateful for the work the EPA has done to support the automotive aftermarket and help create clearer pathways for compliant products,” said Aaron Stewart, the company’s vice president of engineering. “The acceptance of SEMA Certified-Emissions is an important step forward for the industry and helps manufacturers continue developing clean, compliant products that consumers can use to repair, modify, and enjoy their vehicles.”
Brian Herron, CEO of Opus Intelligent Vehicle Support, echoed that view, describing the EPA’s action as both practical and long overdue.
“As a lifelong enthusiast, a right to repair and right to modify advocate, and someone who has spent decades in vehicle diagnostics and the automotive aftermarket, I believe EPA’s recognition of SEMA Certified-Emissions is an important and practical step forward,” Herron said. “This action gives responsible companies a clear, nationally recognized path to demonstrate compliance while continuing to innovate and serve consumers.”
The decision also follows a series of legal and regulatory developments involving California’s emissions authority. In June 2025, the Supreme Court ruled in Diamond Alternative Energy v. EPA that fuel producers had standing to challenge California’s EPA-approved vehicle emissions rules, removing a procedural obstacle that had previously limited such lawsuits.
Meanwhile, EPA officials have continued criticizing California’s broader regulatory approach.
Last September, Assistant Administrator for Air and Radiation Aaron Szabo argued that the state’s emissions policies were restricting consumer choice rather than expanding it.
“CARB’s proposal appears to be nothing more than scare tactics to coerce car companies into limiting consumer choice and selling unaffordable and impractical electric vehicles that Americans do not want to buy,” Szabo said. “California appears dead set on wasting hard-earned taxpayer dollars and forcing their rejected standards on the rest of the country.”
