EPA to revoke California waiver on fuel economy standards. In what would be a dramatic escalation in the standoff between the Trump administration and California over national fuel economy standards, the EPA is preparing to revoke the waiver granted to California that allows the state to set stricter fuel economy standards than the federal government. On a separate track, the EPA is in the midst of trying to water-down federal requirements for automakers. Just weeks ago, major automakers announced a plan to align their operations with the California standards, a blow to the Trump administration. “Going for preemption is the nuclear option,” said Jody Freeman, a Harvard environmental law professor.