WASHINGTON _ The Trump administration sent California a stern warning Friday that its agreement with four major automakers to reduce car pollution appears to violate federal law.
The letter from the Environmental Protection Agency and the Department of Transportation is the latest sign of President Donald Trump's anger at California and the car manufacturers that have bucked at his plans to roll back regulations put in place to combat climate change. Ford, Honda, Volkswagen and BMW have all agreed to voluntarily increase fuel efficiency and reduce emissions, essentially ignoring the Trump administration's plans to roll back car pollution standards.
The letter threatened "legal consequences" if California does not abandon the agreement, but did not say how the administration would respond. It reiterated the administration's long-held belief that only the federal government has the authority to set fuel economy and greenhouse gas emissions standards for cars.
"Congress has squarely vested the authority to set fuel economy standards for new motor vehicles, and nationwide standards for GHG vehicle emissions, with the Federal government, not with California or any other State," the letter said.
The administration sent the letter at the same time Trump is considering revoking a decades-old rule that has allowed California to set car pollution standards that are tougher than the federal government's _ putting the state and the EPA on a path to years of fighting in court.
Since the administration's earliest days, officials have threatened to try to revoke that authority. California officials have denounced the idea.
Further escalating tensions between the state and the Trump administration, the Department of Justice has launched an investigation into whether the automakers violated federal antitrust laws by reaching the agreement with California to reduce emissions. A Justice Department spokesman declined to comment on the inquiry, news of which was first reported by The Wall Street Journal.
"The Trump administration has been attempting and failing to bully car companies for months now," Gov. Gavin Newsom said in response to news of the inquiry. "We remain undeterred. California stands up to bullies and will keep fighting for stronger clean-car protections that protect the health and safety of our children and families."
California's special authority to regulate car pollution dates back to the 1960s, when Los Angeles was enveloped in a thick layer of smog that state officials came to see as a public health crisis. By the time the 1970 Clean Air Act took effect, the state had already enacted its own tailpipe emission controls.
Concerned that each state would pass different regulations, Congress decided that the EPA would set car pollution standards for the nation. But it carved out an exception for California requiring the EPA to grant the state a waiver to set its own rules, provided they were at least as stringent as the federal ones.
Other states could choose to follow either California's regulations or those set by the federal government.
The proposal to revoke the waiver that allows California to set its own regulations is only one step in the administration's plans to weaken car pollution standards.
Current rules require automakers to build increasingly efficient vehicles so that by 2025 the nation's cars and trucks would average more than 50 miles per gallon. The EPA and the National Highway Traffic Safety Administration have proposed freezing mileage targets at about 37 miles per gallon for cars after 2020.
While acknowledging the plan would increase oil consumption and greenhouse gas emissions, the federal agencies have argued that the current standards endanger drivers by making new, safer cars unaffordable.
However, the announcement of this rollback has been repeatedly delayed, and it remains unclear whether the administration will be able to complete its plan.
Independent scientists have poked holes in the agencies' data, senior political officials tasked with working on the rollback have left the administration, and automakers have revolted in opposition to the president's proposal, which they say will hurt their bottom line.
