LOS ANGELES — California without gasoline-burning cars? The idea is starting to be floated.

A top regulator came close Thursday, but ultimately backed away from directly raising the notion of giving the boot to exhaust-belching automobiles, a staple of life in the freeway-happy Golden State for more than a century.

Speaking at an air-quality workshop in San Diego, Mary Nichols, chair of the California Air Resources Board, was expected to toss in the idea of killing off gas-powered cars based on her prepared remarks. They called for her to list ways in which the state can get tougher on pollution.

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“That might mean, for example, tougher requirements for low-carbon fuels, looking at tighter health-protective regulations on California refineries, doubling down on our enforcement efforts on mobile and stationary sources — and might lead to an outright ban on internal-combustion engines,” according to the remarks obtained by Bloomberg News.

But when it came to actually delivering the remarks, the direct reference to a gas-engine ban was omitted. In closing the conference, Nichols said if the air can't be cleaned fast enough, tougher measures like "fees, taxes and bans on certain types of vehicles" might be required. She added, "These are things that most of us don't think is the right way to go."

Nichols wasn't proposing a gas-vehicle ban on a whim, said Simon Mui, senior scientist for the Natural Resources Defense Council. Rather, she was reacting to steps that California may have to take to stay in compliance with toughening federal clean-air regulations. If the state, famous for its smoggy air, were to fall short, it would face sanctions.

"The feds have clearly put the states into a bind," Mui said after attending the conference.

In California, a ban on the sale of internal-combustion cars is considered a fanciful idea. In fact, a bill to ban the sale of internal-combustion cars by 2040 was introduced in the California Legislature last year, though it didn't get far.

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“It’s time that we clear the path for emissions-free transportation and take significant steps to achieve our ambitious emissions reduction goals," Assemblyman Phil Ting, a San Francisco Democrat, said in a statement at the time.

The California New Car Dealers Association opposed the measure, saying the state lacked enough public charging stations to keep all those electrics on the road, that the bill didn't take into account the valuable role played by gas-electric hybrid vehicles and that it was too hard to mandate rules on vehicle sales more than 20 years in the future.

Already, California is the nation's leader in the sale of electric cars. The association says more than 500,000 are on the road.

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Some experts agree the timing isn't yet right to talk about a gasoline-free future.

"California has always been a visionary when it comes to 'green' cars," said Ron Cogan, publisher of the Green Car Journal.

"It's not surprising there are elements in government who want to move us away from internal-combustion cars." But "given the high cost of electric cars and that a great majority of entry-level buyers can't afford them, it's too early about talk about taking gas-powered cars off the road," Cogan said.

Given the charging challenge and other issues, "so many things have to happen before that is financially or fundamentally possible," he added