Chipmaking companies burdened by seeping problems.

Add this to the list of reasons why it's better to send chip production overseas: It's dirty.

Well, at least it can be.

Chip factories, called fabrication plants or "labs," long have been courted as clean manufacturing. And they are, compared with the smokestack industries of the old economy.

But leaks of chemicals used to make chips can take years--sometimes decades--to clean up. Costs can run into the millions of dollars.

Just ask Irvine-based Microsemi Corp. and Newport Beach-based Conexant Systems Inc., two of the area's larger chipmakers.

The companies, which once employed hundreds in specialized chip plants in Orange County, still are dealing with cleanup from pollution incidents that happened more than a decade ago.

Back in 1988, Conexant, then the chip arm of what was Rockwell International Corp., found a leak in a tank used to store production chemicals at its Newport Beach plant.

The chemicals, used to clean silicon wafers, were stored in massive underground tanks. They leaked into the ground, spreading as far as 300 feet and tainting groundwater around the facility, according to a Conexant spokeswoman.

Since then, Conexant has finished its cleanup and is "just waiting to be re-inspected," said Conexant spokeswoman Gwen Carlson.

The Newport Beach plant now belongs to Jazz Semiconductor Inc., which spun off from Conexant in 2002.

In another Conexant case, the groundwater near a plant in Parker Ford, Pa., also dating back to the Rockwell era, was so contaminated that the Environmental Protection Agency listed it as a "superfund" site. That's a designation for sites that are so costly to clean up that they require government spending.

According to the most recent update on the EPA Web site, a "groundwater pump and treat system has been operating since 1998, cleaning the groundwater."

While both cases are more than a decade old, they also underline a risk for chipmakers. It can take years and millions of dollars to clean a spill.

In 2004 alone, Conexant's management "estimates the aggregate remaining costs for the (Newport Beach and Parker Ford) remediations to be approximately $3 million," the company said in its most recent quarterly filing with the Securities and Exchange Commission.

A particular concern is a chemical used for industrial cleaning, trichloroethylene, or TCE, which is suspected of causing cancer.

Silicon Valley is perhaps the most TCE-tainted area in the country, with some 23 superfund sites. "All the superfund sites in Silicon Valley had contaminated groundwater," said Paula Bruin, a public affairs officer for the EPA.

Orange County has only two superfund sites, neither related to chipmaking: the former Marine base at El Toro and the McColl dumpsite in Fullerton.

If a chipmaker is lucky, polluted ground can be dug out. Or the chemical can be sucked out of the dirt. Things get trickier if the chemical leaks into groundwater. Then a chipmaker has to pay to draw the groundwater out, filter it and put it back in.

"These chemicals are definitely hazardous," said Paul Bibeau, general manager of Microsemi's integrated products group in Garden Grove, where the company has a chip plant. "We have to use tremendous care in how we handle and dispose of them."

The government has "established a certain amount of cradle-to-grave liability and a high degree of chemical accounting," said Rob Norwood, a plant manager at Microsemi's Garden Grove facility.

But leaks happen. A holding tank at Microsemi's Garden Grove plant sprung a small leak, seeping chemicals into the ground, Norwood said.

Lucky for Microsemi, they didn't reach the groundwater and were easily cleaned up, he said. "We had that actively remediated," Norwood said.

The cost wasn't enough for Microsemi to make mention of it in its SEC filings. Its plant in Broomfield, Colo. did make it into the company's federal filings.

There, a local business owner next to the plant claimed chemicals contaminated his property. "We vigorously contest any assertion that the subsidiary caused the contamination," Microsemi said in a filing.