Updated

California regulators on Thursday were considering a 90 percent cut in the number of battery-powered and hydrogen vehicles that automakers must produce by 2014, a move that would weaken tough auto emissions rules that 12 other states have adopted.

Auto manufacturers say they can't meet the deadline, but the proposal before the California Air Resources Board has drawn criticism from environmentalists, health advocates and some leading political figures. They question whether the state can afford to relax the rules on automakers in the era of global warming.

"Our goal here today is to emerge with a whole new direction that will get this program on track," air board chairwoman Mary Nichols said. "Our goal is to have California's vehicle program to be the testbed and California be the state where manufacturers first bring their best, cleanest technology."

California has modified its zero-emission vehicle mandate four times since introducing it in 1990. The rule originally required that by 2003, 10 percent of new cars sold in the state by six major auto manufacturers be completely nonpolluting.

The deadline has since been set back and the mandate significantly scaled back. The current rules call for at least 25,000 zero-emission vehicles — ones powered by hydrogen fuel cells or batteries — in California by 2014.

Automakers are also required to produce lower-emission vehicles such as hybrids and cleaner-burning gasoline vehicles.

The recommendation before the Air Resources Board on Thursday would require only 2,500 such vehicles by that year from General Motors Corp., Toyota Motor Corp., Ford Motor Co., Honda Motor Co., Chrysler LLC and Nissan Motor Co. Nichols, however, said the board may not adopt it.

"I think that rollback is more extreme than what the board would go for," Nichols said in an interview before the meeting. She described the previous board's action in 2003 as a mistake.

The air board also will be asked to decide whether automakers should be given more time to deploy battery-powered and hydrogen cars in the 12 states that have adopted California's rules: Connecticut, Maine, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont and Washington.

California, with its long history of air pollution, is the only state allowed to go beyond federal law in setting such environmental standards, but other states can follow its lead.

To offset a lower mandate on zero-emission vehicles, the air board's staff proposes that automakers instead put 75,000 gas-electric hybrids on the road between 2012 and 2014. It also would require automakers to continue making more fuel-efficient gasoline vehicles.

That shift would satisfy the air quality goals of the program and save auto manufacturers $1.3 billion a year while they explore new technology, according to a report by the Air Resources Board staff.

Critics of rolling back the regulations include former Secretary of State George Shultz and former CIA Director James Woolsey.

"(The air board) is on the verge of doing a great disservice to our national security, increasing our dependence on oil, to putting off the day when we can drive on something other than oil in the very, very distant future," Woolsey said Wednesday during a capital news conference.

Though lower-emission vehicles — especially hybrids — have begun making an impression in the marketplace, the main automakers still do not have a commercial zero-emission vehicle.

General Motors spokesman Dave Barthmuss said automakers are spending hundreds of thousands of dollars to build one fuel-cell vehicle or battery-powered car. Such a vehicle would cost far more than the average American can afford, he said.

GM also has spent about $10 million on hydrogen fueling stations because not enough of them have been built to support the vehicles regulators are demanding.