LOS ANGELES (AP) - California officials are suing the U.S. Environmental Protection Agency in hopes of reversing a decision requiring vehicles in the state to use the gasoline additive ethanol.

The lawsuit, filed Friday afternoon in the 9th U.S. Circuit Court of Appeals in San Francisco, calls on the agency to waive rules requiring ethanol to be added to most of the state's gasoline. Ethanol adds oxygen to gasoline to make it burn cleaner.

Gov. Gray Davis has ordered that MTBE - the only oxygenate available besides ethanol - be phased out by 2003 because it pollutes ground water. State officials argue that California can meet federal air-quality goals with non-oxygenated, reformulated gasoline.

The EPA's oxygenate requirement is "a straitjacket mandate that will drive up gas prices while increasing air pollution," Davis said in a statement. "The potential for harm to Californians, both economically and environmentally, leaves me no choice but to fight back with guns blazing."

California produces 5 million to 7 million gallons of ethanol a year, a far cry from the estimated 600 million to 900 million gallons it would need to comply with the rules. Officials say the ethanol requirements would make the state dependent on the Midwest, which grows the corn used to make most ethanol.

Winston Hickox, secretary of the California Environmental Protection Agency, said California's ethanol needs could create supply problems and send prices skyrocketing.

Representatives of two environmental groups, the Natural Resources Defense Council and the Clean Air Trust, also said at the news conference that requiring ethanol could do more harm than good to California's air.

Studies have shown that while ethanol blends reduce carbon monoxide levels, they increase levels of oxides of nitrogen.

EPA officials in Washington, D.C., and San Francisco did not return several calls seeking comment Sunday.

The EPA has contended that under the Clean Air Act, it lacks the authority to grant the state's request. Federal officials have said the state hasn't proven that complying with the oxygenate requirement would increase air pollution.