SEATTLE — Officials on Friday upped their estimate of the oil leaked from a corroded pipeline at the northern tip of Alaska to at least 265,000 gallons, making it the largest spill on record in the oil-rich North Slope field — and one of the worst in the 29-year history of the Trans Alaska Pipeline System.
The report by Alaska's Department of Environmental Conservation added grist to the debate over President Bush's push to drill for oil in the nearby Arctic National Wildlife Refuge; industry advocates say the drilling can be done with minimal ecological impact, but environmentalists contend it would threaten the fragile ecosystem.
A second leak was detected Friday in a separate transmission pipeline in the North Slope complex about 300 miles north of the Arctic Circle. The extent or cause of that spill was unknown, but it was not expected to be nearly as large, officials said.
The main spill was discovered March 2 and plugged last weekend. The largest spill along the pipeline occurred shortly after it opened; in 1978, vandals blew up a section of the 800-mile line and spilled 700,000 gallons of oil.
In October 2001, a hunter fired his rifle into the pipeline, causing a 280,000-gallon spill and a cleanup that cost $7 million.
The worst oil spill in Alaska history was in 1989, when the Exxon Valdez tanker ran aground in Prince William Sound, dumping 11 million gallons.
Environmental advocates said Friday that the recent spills were evidence that oil drilling posed a continuing threat.
is a catastrophe for the environment," Natalie Brandon, policy director for the Alaska Wilderness League, said of the main spill. "The fact that the oil spill occurred in a caribou-crossing area in Prudhoe Bay is a painful reminder of the reality of unchecked oil and gas development across Alaska's North Slope.
"Aging infrastructure, corroded pipes and failed leak-detection systems ensure that more big accidents like this are a matter of time," said Brandon, "especially if Congress opens up the refuge."
Industry officials have disputed such warnings, calling the pipeline system one of the safest and most carefully regulated in the world. Spills represent less than one-thousandth of 1% of the volume delivered since the pipeline system opened in 1977, they said.
"If you look at the fact that we've delivered 15 billion barrels of oil down that line since it opened, if you compare any amount of oil spilled, it's a tiny fraction," said Daren Beaudo, a spokesman for BP Exploration (Alaska), the operator of the pipeline stretch. There are 42 gallons to a barrel.
"But of course we're concerned about any spill scenario," Beaudo added.
He said that the spill area had been contained to less than two acres and that berms were preventing the spill from spreading. Cleanup operations were continuing despite subzero temperatures, he said.
It is not clear when the quarter-inch-leak in the pipeline occurred. But Lois Epstein — an engineer and oil and gas analyst with Cook Inlet Keeper, a nonprofit environmental group in Anchorage — said: "This incident appears to show that, especially with an aging pipeline system, you can have situations where you have small leaks that go on for a long time.
"That's not good for anybody," Epstein said. "It's not good for the company, it's not good for the environment, and it's not good for the caribou."
The pipeline system stretches from Prudhoe Bay on the Arctic Ocean across the tundra, over or under hundreds of rivers and streams and through two mountain ranges before it reaches its southern terminus in Valdez, on the Gulf of Alaska. From there, most of the oil is delivered in tankers to West Coast refineries.
© 2006 Los Angeles Times