BP Exploration (Alaska) Inc. on Tuesday raised the estimated of spilled crude from three gallons to as much as 100 gallons. In all, about 300 to 700 gallons of oil, corrosion inhibitor and produced water spilled, according to Tuesday's DEC report on the spill.
DEC officials acknowledged that it's difficult to accurately assess volumes when varying substances spill but also say that DEC officials at the scene saw much more spilled oil than what BP initially reported.
The spill happened after a 6-inch line carrying a mixture of crude, produced water and natural gas broke where it left the well house. The reason for the break is still under investigation.
Before the spill, the oil well was shut down for 58 hours while 135 gallons of corrosion inhibitor was injected into the well head. All of that probably spilled, as well as crude oil and oily water pumped up from the well, according to the new report. About 6 acres of snow-covered tundra as well as the gravel pad were contaminated.
BP operates Prudhoe Bay, North America's largest oil field.
Last month, one of the North Slope's biggest spills -- 46,000 gallons of oil and water -- occurred when an 18-inch flow line at the Lisburne field split open. Officials say ice plugs had formed in the line and caused pressure to build up. That spill remains under investigation.
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