CARB Drops Request for EPA Waiver

California has abandoned its multi-year effort to phase out diesel truck engines.

In a Jan. 13 letter, the California Air Resource Board (CARB) announced it was withdrawing its request for required waivers from the Environmental Protection Agency (EPA).

The waivers were necessary to implement key aspects of the Advanced Clean Fleets rule that exceeded federal emissions standards. The EPA responded the next day that it would take no further action on the request and “considers this matter closed.”

CARB Chairwoman Liane Randolph said the withdrawal was in response to “the uncertainty presented by the incoming [presidential] administration that previously attacked California’s programs to protect public health and the climate and has said will continue to oppose those programs.”

The Advanced Clean Fleets rule has been tied up in litigation for months, including a suit filed in May by 16 states.

The EPA held a hearing in August on two waivers tied to the Advanced Clean Fleets rule. It had previously granted a waiver in 2023 for other aspects of the proposed diesel phase out.