The Senate Parliamentarian has told Majority Leader John Thune (R-SD) that waivers issued by EPA under the Clean Air Act are not subject to recission through the Congressional Review Act. If the Senate accepts this opinion, then it would not be able to rescind the waivers issued to CARB. The EPA would have to go through another rulemaking to withdraw the waivers.

Nevertheless, on Friday Senate Republicans introduced resolutions to revoke California's federal permission to set its nation-leading vehicle emissions standards. Sens. Shelley Moore Capito (R-WV), Deb Fischer (R-NE), and Markwayne Mullin( R-OK) introduced a trio of measures to roll back EPA waivers approved under the Biden administration that allow California to enforce zero-emission sales mandates for cars and heavy-duty trucks, along with stricter emissions standards for diesel trucks.

It is unknown at this point whether Speaker Thune will attempt to override the Parliamentarian’s decision.