Unocal May Be Charged in Petroleum Spill : Environment: More than 591,000 gallons of thinner have leaked from aging oil field pipelines along coast, state says. Firm admits breaks, but denies any cover-up.

Unocal Corp. could face criminal charges for spilling more than 591,000 gallons of petroleum thinner along the Central California coast near Guadalupe in a series of pipeline breaks the company failed to report, authorities said.

The onshore spills occurred between 1986 and 1990 at the company’s aging oil field near the Santa Barbara-San Luis Obispo County line, contaminating the ocean, beaches, wildlife, soil and underground water, according to an investigation by the state’s new Office of Oil Spill Prevention and Response.

The investigative report was forwarded last week to San Luis Obispo County Dist. Atty. Barry La Barbera, who will determine if criminal or civil charges will be filed against Unocal or its officials.

The company acknowledges spilling a large quantity of diluent--a clear, diesel-like liquid--into the ocean but denies that it engaged in a cover-up of the spills.

Janet McClintock, a Unocal spokeswoman, said the company notified the state of the problem in 1989 when tests concluded that an oily sheen found on the ocean and beaches was diluent from the oil field.

“To my knowledge, there wasn’t some incident that would be called an oil spill,” she said. “We don’t know where it came from, other than it’s something from that whole system of pipelines.”

State investigators who raided Unocal offices this summer and seized boxes of documents and computer records have attempted to reconstruct how much diluent leaked from the pipelines by examining pressure gauge readings.

Authorities said they expect that the amount is far greater than the 591,000 gallons recovered by Unocal since 1990, when the company built an elaborate 1,000-foot underground barrier at the beach to halt the flow of thinner into the Pacific.

But investigators may never know how much diluent reached the ocean before the barrier was built.

“The potential is there for significant amounts to have gone out prior to that time and for significant amounts still to be traveling to that wall,” said Bill Gengler, a spokesman for the state agency.

By comparison, the infamous Huntington Beach oil spill in 1990 totaled 399,000 gallons of crude oil that flowed into the ocean and onto Orange County beaches from a British Petroleum tanker.

Animal rescue workers have complained for years of an oily sheen found on sea mammals along the Central Coast. They contend that diluent spills from the Unocal oil field have killed dozens of sea lions, seals and other animals.

“We kept picking up seals and the problems were never addressed,” said Kathy Johanes, director of the North County Wildlife and Marine Mammal Rehabilitation Center in Paso Robles. “In 1988, we had 65 animals suffering seizures over 3 1/2 months. Nobody would even take a look at the fact that Unocal might be to blame.”

Because the crude oil beneath the Guadalupe field is very thick, diluent has long been used as a thinner to help pump the oil out of the wells and through pipelines.

Diluent, which is a petroleum product, costs more per barrel than most unrefined crude oil, McClintock said. “It was never to our economic advantage to lose track of it,” she said.

The diluent is pumped through a network of underground pipes, which can make it difficult to determine where leaks have occurred.

Once it became clear that diluent was flowing underground and into the ocean, Unocal built the barrier on the beach 18 feet deep, McClintock said. More than 20 small wells were dug to pump the diluent out of the ground. Nearby, at the mouth of the Santa Maria River, Unocal removed more than 900 cubic yards of contaminated soil.

Despite these efforts, an affidavit for a search warrant filed by the Office of Oil Spill Prevention and Response contends that diluent was still leaking onto the beach and into the ocean in 1991 and this year. The affidavit also cites evidence that diluent has been flowing from the oil field into the ocean for the last 20 years.

Furthermore, state investigators have received evidence that Unocal has been attempting to cover up diluent leaks at the Guadalupe field since 1978, the affidavit said.

Investigators contend that many breaks in the pipes were not reported to the state as required by law. Possible charges against Unocal employees, according to the affidavit, include pollution of state waters by a petroleum product.

The district attorney’s office said La Barbera would have no comment on the investigation until he reviewed the report.

But McClintock said the state was properly notified of the problem at Guadalupe and that the Department of Fish and Game approved the plan for building the beach barrier and pumping out the diluent. The problem of contamination, she said, has been stopped.