Report Fails to Identify Cause of Oxnard Oil Spill : Environment: Berry Petroleum study also does not address how the accident went unnoticed for three days.

A report issued by Berry Petroleum, the Taft-based oil company responsible for one of the worst pipeline spills in Ventura County history, fails to address what triggered the spill and how it went undetected for three days, state investigators said Wednesday.

The 15-page document, which said the cause of the rupture is still unknown, was submitted to the Regional Water Quality Control Board after the oil company received a two-week extension.

“Obviously, there are a few things that need to be figured out,” said Shirley Birosik, a state water quality investigator. “I will be asking for a supplemental report that would include more information.”

But a Berry Petroleum official on Wednesday said the report represents all of the information about the spill the company has been able to piece together.

More than 84,000 gallons of thick crude leaked from an underground pipeline into ecologically sensitive McGrath Lake and the ocean near Oxnard, after at least six law enforcement agencies failed to follow up early reports of the spill.

The ruptured pipeline spewed heavy crude for at least three days before a federal Minerals Management Service worker spotted offshore oil slicks early Christmas morning.

The Jan. 21 report downplays the effects of the crude oil on the environment, concluding that roughly a quarter-acre of reed and marshland was damaged and that “the effects were limited to transient visual impacts.”

The state released copies of the report Wednesday after consulting its attorneys and investigators. It concludes that there is no apparent or potential ground water contamination attributable to the spill, and that it has caused no known public health risk.

Brent Winn, the Berry Petroleum environmental coordinator who prepared the analysis, listed more than 215 birds and other species that died after the spill.

But, he wrote, “It is important to note that it has not been established that the attached list represents species killed as a result of the (oil) release.” He declined Wednesday to discuss his findings.

The dead birds include two California brown pelicans, which are on the federal government’s list of endangered species. However, one of the two was found badly decomposed and likely died from other causes, Winn reported.

Mark Caywood, the state Department of Fish and Game inspector heading the investigation, also called the report incomplete.

“It lacks some fortitude as far as exact cause and responsibility and not noticing (leakage) for a prolonged period of time,” said Caywood, who by April will recommend to local prosecutors whether criminal charges should be brought against Berry officials.

“However, it’s quite normal to get kind of a wimpy (report),” he said. “They’re not going to put anything in writing as long as there’s a chance of litigation. It’s normal that when anything can be litigated, you keep your mouth shut and let the attorneys do the talking.”

Caywood said he already knows much about why Berry failed to shut down the pipeline for “a period of days,” but declined to discuss the ongoing investigation.

“I’ve got answers, but I can’t say they’re entirely satisfactory,” said Caywood, who said the cleanup may be signed off by next week.

An oil company official said Wednesday he had no idea how workers failed to notice for three days that the oil was not reaching its designated holding tank.

“When we have an answer to that we’ll address it to the agencies and it will become available,” said spokesman Ray Hatch. “All the information that we have is in the letter we sent to the regional water board.”

Investigators first suspected that interference from nearby pipelines equipped with electric safety devices hastened the break because Berry Petroleum never installed one of the units on the ruptured pipeline.

Cathodic protection devices emit small electric currents that help prevent external corrosion, but they are not always required by law.

An official with the state division of oil and gas said earlier this month that the top two likely reasons for the break were structural failure or internal corrosion, symptoms unrelated to electrical interference.

Most of the oil has been cleaned up from the different spill sites. On Wednesday, a crew of workers manned a single boat on the lake surface, apparently gathering samples from the lake bottom.

Heidi Togstad, a fish and game environmental specialist, said cleanup crews now are concentrating their efforts on the creek and upper portion of the tiny, 10-acre lake.

“They are cutting vegetation from the entire perimeter of the lake,” she said. “Entire trees have been taken out of the creek to remove oily debris, sediment and roots.”

Richard Rojas, chief ranger for the Channel Coast District of California State Parks, said experts are now evaluating how best to remove oil that has settled to the bottom of McGrath Lake.

“But we don’t yet know how to do it, whether we should try to dredge it out, suction it out or drain the lake and remove it that way,” he said.

Birosik, the water quality investigator, said she would request a supplemental report from Berry Petroleum early next week.

“I’m eventually going to get the information,” she said.

Times staff writer Joanna M. Miller contributed to this story.