Mar. 30--More than half of the state's gas stations will miss a Wednesday deadline for scrubbing toxic vapors from their pumps, setting them up for hefty fines or eventually even closure, officials say.

An estimated 2,000 of the 3,900 service stations in Southern California have not yet installed next-generation vapor-trapping systems, although they've known for years about the April 1 deadline, according to local air quality regulators.

Realizing the scope of the problem, lawmakers have proposed two bills seeking a delay. Independent gas station owners also want a year's extension, predicting a wave of closures if they're penalized for noncompliance.

"You're going to see gas stations shut down. You're going to see massive unemployment. You're going to see (gas) prices creep up. You're going to see blight in urban areas," said Tom Kise of the Responsible Clean Air Coalition, a group of independent oil marketers advocating an extension. "It's going to have a devastating effect across California."

Local gas station owners blame a combination of bureaucratic bungling, the tight credit market and dire equipment shortages for their inability to install the vapor filters.

"It's extortion, is what it is," said Chatsworth businessman Andre van der Valk, who faces thousands of dollars in fines for not yet installing the equipment at his three independent gas stations.

At issue is the so-called enhanced vapor recovery system, ordered by the California Air Resources Board to remove smog-producing vapors emitted at gas stations.

Regulators say the EVR equipment will filter 10 tons of harmful hydrocarbons -- the equivalent of 450,000 cars -- emitted when motorists fill up at the pump. In Southern California, the systems will remove about 1.4 tons per day.

Research has found that the volatile organic compounds can exacerbate heart and breathing problems. One compound, benzene, can cause cancer.

But the health measures come at a price.

The nozzles and other EVR equipment cost about $11,000 a pump, or roughly $75,000 a station -- costs expected to be passed on to motorists with a 1cent-per-gallon increase.

State air regulators say the EVR mandate was set in 2000. Equipment to retrofit most pumps has been available since 2005, officials say, with the state extending credit to help station owners make the purchase.

Critics, however, vehemently disagree. They said the 2005 EVR system worked on only 10 percent of station pumps. They also dispute that the state offered financial help to the station owners.