SACRAMENTO — California’s ambitious law to curb global warming took aim at the computer chip industry Thursday, as regulators adopted rules to force semiconductor makers to cut greenhouse gas emissions by more than half by 2012.

The vote by the California Air Resources Board is among early steps state officials are taking to comply with AB 32, the 2006 law championed by Gov. Arnold Schwarzenegger to lower total greenhouse gas emissions in California to 1990 levels by 2020.

The regulations target the use of fluorinated gases in processing blank wafers into finished chips that are installed in computers, cell phones and cars. The state has 85 semiconductor plants, most in the Bay Area.

Fluorinated gases such as sulfur hexafluoride and nitrogen trifluoride are among the most potent contributors to global warming. The gases covered by the regulations approved Thursday trap heat in the atmosphere at 6,500 to 23,900 times the rate of carbon dioxide, the primary greenhouse gas, according to the air board.

Regulators say other, less harmful gases can be used instead, at a small cost to semiconductor firms. The air board estimates the annual cost of compliance with the new rules at $37 million over 10 years; the brunt of that total would fall on 13 semiconductor companies that operate 16 plants currently not in compliance with the new emissions target. Among them: Universal Semiconductor, Linear Technology Corp. and Intel’s Mission Campus.

But one representative of the chip industry said swapping chemicals used to make semiconductors is not as easy or inexpensive as regulators claim.

“To have them, in effect, substitute their experts for those involved in semiconductor manufacturing — I just have to say I’m skeptical,” said John Greenagel of the Semiconductor Industry Association. “Is this really a good time to be making it more difficult to be in the semiconductor business in California?”

Such disputes with California businesses are expected to intensify in the coming months and years, as regulators implement Schwarzenegger’s sweeping greenhouse gas law. The semiconductor regulations approved Thursday are considered much less contentious than upcoming rules that will target power plants, automakers and cement manufacturers, among others.

“This is the traditional low-hanging fruit,” said Leo Kay, a spokesman for the air board.

The regulations affecting the semiconductor industry would curb the equivalent carbon dioxide emissions of 36,000 cars for a year. A related regulation targeting non-semiconductor operations that emit fluorinated gases — they are used in medical devices and to make tennis balls, for example — would head off the emissions of another 20,000 cars, regulators said.

The new rule is intended to lower greenhouse gas emissions in the chip industry by 56 percent. It takes effect in January 2012, although companies that plan to upgrade their equipment would be given until 2014 to comply.

Carl Guardino, president of the Silicon Valley Leadership Group, said his organization, which represents many high-tech firms, supports the greenhouse gas law. But he urged regulators to be cognizant of the industry’s struggles.

“We don’t have the attitude that ‘this is important, but go burden someone else,’ ” Guardino said. At the same time, he added, “We have to be sensitive to do what’s best for the environment and the economy, and that is the tightrope this economic climate has put us all on.”