Estimates of Oil Loss in Pipeline Rupture Soar : Environment: About 84,000 gallons of crude have spilled at McGrath State Beach near Oxnard. Workers continue to remove it from sand and a nearby lake.

Estimates of crude oil lost from a pipeline rupture at McGrath State Beach near Oxnard increased eightfold Monday, to about 84,000 gallons, as authorities revealed that the leak may have occurred many hours--or even days--before it was discovered Christmas morning.

During a third day of cleanup, more than 100 workers continued to shovel crude from a one-mile stretch of soiled beach and suck a thick cap of oil from the surface of a fragile coastal lake so damaged it will take decades to recover, authorities said.

McGrath State Beach remained closed, and officials warned swimmers and surfers to stay out of the ocean along seven miles of beach from Ventura Pier south to Channel Islands Harbor in Oxnard. Black globules and an oily sheen were in the sea along that stretch of coast.

Meanwhile, the count of dead and injured birds rose to 55; one muskrat also smothered in the oil.

Despite escalating estimates of leaked oil and dead animals, state and federal officials said the cleanup was going well. Of the total spill of about 2,000 barrels, about 400 had been recovered from the half-mile-long McGrath Lake, a fresh-water drainage basin just inland from the beach.

Another 50 barrels had been skimmed from the ocean by boats that were withdrawn Monday as officials declared an end to the ocean phase of the cleanup.

“It’s going very well,” said U.S. Coast Guard Cmdr. Jim Rutkovsky. The Coast Guard was involved because the oil flowed into the ocean.

No progress has been made, however, in determining what caused the eight-inch-diameter pipe to break.

A spokesman for Bush Oil Co., which uses the pipeline to transport oil between two storage tanks, said the company is concentrating on an around-the-clock cleanup, not the cause of the break.

“This is a crisis mode,” said Jerry Hoffman, president of Taft-based Berry Petroleum, parent company of Bush Oil.

Neither Hoffman nor company spokesman Raymond L. Hatch would comment on when the pipeline was last checked for stress, although Hatch said previously that it was within the last year.

Hatch also declined comment on the age of the pipeline, its maintenance schedule, when it began to leak or the maximum amount of oil that could have leaked from it. “When we have that information, we’ll release it,” Hatch said.

In a statement, the company said about noon Monday that “at this time it is believed that the total discharge exceeded the original estimates and may be in the range of 1,800 to 2,000 barrels. . . . The company is also investigating reports that the discharge may have started earlier than Christmas Day.”

The rupture was discovered about 7:25 a.m. on Christmas by federal Mineral Management Services employees flying over the beach. Bush Oil, which was notified about two hours later, shut down the line by 10:15 a.m., the company said.

The company estimated Saturday that only 10 barrels had leaked, increased its estimate to 252 barrels on Sunday and reached Monday’s much higher figure at the urging of the Coast Guard, said Rutkovsky.

“The Coast Guard says at least 1,800 barrels (leaked),” Rutkovsky said. “It’s going to go above that, but it won’t be double that.”

Rescue workers vowed Monday to work from “first light to last light” for several weeks if necessary to find dead or injured wildlife.

The dead and injured birds included sandpipers, coots, ruddy ducks, shoveler ducks and other shorebirds, California Department of Fish and Game officials said.

“A lot of the rescued birds won’t live,” said Fish and Game veterinarian David Jessup, who evaluated the birds immediately after they were pulled from the lake in a specially equipped department motor home.

“This oil is particularly nasty stuff.”

None of the dead or injured animals were endangered species, many of which nest or forage at McGrath Lake and the nearby Santa Clara River Estuary. It appeared Monday that the Santa Clara River estuary h ad not been contaminated, officials said.

Wildlife officials are hopeful that no migrating or resident birds will visit the area until the cleanup is complete.

“We’re crossing our fingers that the birds will avoid the lake because of all the activity,” said Heidi Togstad, Fish and Game coordinator for wildlife restoration and rehabilitation for the incident.

Mimi Wood of the International Bird Rescue and Research Center, said some animals, such as the endangered California brown pelican, could have been partially coated with the oil and could now be sitting on nearby ocean breakwaters, becoming dehydrated and hypothermic as they lose their body heat.

Although Bush Oil officials said they could provide no information about previous leaks or spills at its Oxnard field, a state agency that oversees pipeline safety in oil fields said the Bush facility has a good record.

The ruptured pipeline passed a pressure test in March and company officials have told the state that such tests--though not mandatory--are administered annually, said Kenneth P. Henderson, a supervisor in the oil and gas division of the state Department of Conservation.

Henderson said that his department has no record of reported leaks at the field during the 3 1/2 years Bush has owned it or since January, 1986, under a previous owner, Chevron USA.

“So it looks like it’s been operated in a conscientious manner,” he said.

Bush Oil officials said they could not estimate how long the cleanup will take. They said the full costs of the effort will be paid by the company’s insurance.