California and 15 other states filed a lawsuit on Wednesday against the federal government for denying them the right to apply stricter car emissions standard for fighting global warming.
The lawsuit challenges the decision of the Environmental Protection Agency (EPA) last month to deny California a waiver to pass its own tailpipe rules, which is permitted under the 1970 Clean Air Act.
The Clean Air Act allows other states to follow California rules or federal rules on the air pollution issue, so long as the federal government grants California a waiver.
The federal agency has approved about 50 waivers in the last three decades, but in the latest case, EPA officials contended that energy legislation passed recently by Congress increases vehicle fuel efficiency so much as to render the waiver unnecessary.
California Governor Arnold Schwarzenegger, in a statement issued Wednesday, called the EPA decision "unconscionable."
"They are ignoring the will of millions of people who want their government to take action in the fight against global warming," the governor said.
Jerry Brown, California's attorney general, called the EPA's denial letter "shocking in its incoherence and utter failure to provide legal justification for the administrator's unprecedented action." He said the EPA has done nothing at the national level to curb greenhouse gases.
It is estimated that cars generate about 20 percent of carbon dioxide emissions in the United States, but in California, which has banned coal-fired power plants, the proportion is about 30 percent.
The 15 states joining California in the lawsuit include Massachusetts, Arizona, Connecticut, Delaware, Illinois, Maine, Maryland, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont and Washington.