The state that made smog famous is losing its half-century-old authority to set air pollution rules.
President Donald Trump announced Wednesday on Twitter that the Environmental Protection Agency was withdrawing California's authority to issue stricter vehicle efficiency rules than the federal government.
The move was the latest in the administration's efforts to loosen regulations aimed at reducing greenhouse gas emissions.
Thirteen states and the District of Columbia follow California's standards. Together, they account for a third of auto sales in the United States.
California has pledged to fight the decision.
"It's a move that could have devastating consequences for our kids' health and the air we breathe if California were to roll over," California Gov. Gavin Newsom, a Democrat, said in a statement. "But we will fight this latest attempt and defend our clean car standards."
Trump tweeted that the administration was revoking California's air pollution prerogative "in order to produce far less expensive cars for the consumer, while at the same time making the cars substantially SAFER."
Opponents said the action was illegal and unwise.
"It slams the brakes on technological advancement and throws a wrench into states' ability to deal with air pollution and confront the growing risk of climate change," Ken Kimmell, president of the Union of Concerned Scientists, said in a statement. "It's yet another way the administration is defying science, the law and democratic norms to enable increased pollution."
Led the way
California has set its own air pollution rules since the late 1960s. Responding to eye-watering smog in Los Angeles, the state issued the nation's first vehicle air pollution rules in 1966. When the 1970 Clean Air Act was passed, the state was allowed to request waivers to issue stricter standards than the federal government's.
The EPA has approved more than 100 such waivers, according to the California Air Resources Board. None has been revoked. It's not clear if the EPA has the authority to take back a waiver once it has been issued, according to Richard Revesz, director of New York University School of Law's Institute for Policy Integrity.
"This attempt to revoke California's authority has no legal basis, and it is an affront to the well-established rights of California and more than a dozen other states," he said in a statement.
Revoking California's waiver is the first salvo in an attempt to lower vehicle efficiency standards nationwide.
During the Obama administration, the EPA required auto manufacturers' fleets to average 54.5 miles per gallon by 2025. The Trump administration plans to lower the standard to 37 mpg for model years 2021 to 2026.
Automakers initially came to the administration asking for relief from the Obama administration's vehicle efficiency standards. But several major manufacturers have switched sides. Ford, Volkswagen of America, Honda and BMW signed an agreement with California to follow the state's efficiency rules.
Other regulations targeted
The Trump administration is working to undo climate regulations across the board. The EPA has loosened rules for carbon dioxide emissions from power plants and weakened emissions restrictions from oil and gas drilling of methane. The Department of Energy is relaxing efficiency rules for light bulbs. These rollbacks and others face court challenges.
The Trump administration is rescinding permission California received in 2013 for programs that lower vehicle greenhouse gas emissions and mandate zero-emissions vehicles.
The EPA says California does not need the waiver because these rules "address environmental problems that are not particular or unique to California."
Lower costs predicted
The administration says revoking California's waiver will lower costs for consumers and make newer, safer cars more affordable.
EPA Administrator Andrew Wheeler told the National Automobile Dealers Association on Tuesday that automakers have to sell more electric vehicles in order to meet the higher efficiency standards. EVs cost more to manufacture but are less popular than conventional vehicles, he said.
"One way for automakers to meet the standards is to lower the price of electric vehicles and raise the price of other, more popular vehicles, such as SUVs and trucks," Wheeler said. "In other words, American families are paying more for SUVs and trucks so automakers can sell EVs at a cheaper price."
Environmental and consumer groups note that drivers spend less on gas under California's standards.
"The existing standards will save drivers money at the pump, cut hazardous air pollution and help us address climate change," Luke Tonachel, director for clean vehicles and fuels at the Natural Resources Defense Council, said in a statement. "Cleaner, more efficient cars are cheaper to own because the fuel savings dwarf any initial expense."
The administration also says lowering vehicle costs will save hundreds of lives per year because it will be easier for people to buy newer, safer cars, a claim opponents question.
"Pretending that automakers cannot make cars that are both safe and efficient is ridiculous," Tonachel said.