The company that operates the trans-Alaska pipeline is working on building a bypass line so the flow of North Slope oil can be restarted despite a leak.
The pipeline, which transports crude from the nation's largest oil field to the Valdez tanker terminal, was shut down Saturday after the leak was discovered in an underground pipe near a pump station.
Alyeska Pipeline Service Co., which operates the 800-mile pipeline from Prudhoe Bay, had welders working around the clock on the bypass line to circumvent the leak and restore the flow of oil.
Meanwhile, oil production on the North Slope was cut by 95 percent.
The trans-Alaska pipeline normally carries 620,000 barrels of crude oil daily worth more than $50 million. The pipeline is owned by BP PLC and four other companies.
The shutdown helped push oil prices above $90 a barrel Tuesday.
"We are really focused on getting the pipeline restarted," said Katie Pesznecker, a spokeswoman for a joint information center of Alyeska, federal and state officials set up in Fairbanks. "It is critical that we get it moving again as soon as possible."
Shutdowns in winter are concerning because of the potential for ice buildup in the line that can damage machinery during a restart.
Pesznecker said workers were placing temperature sensors on the pipeline and oil was being circulated at various pump stations to keep it warm and moving.
Alyeska engineers were designing a 170-foot-long, 24-inch-diameter bypass pipe to get oil to the main line. It wasn't known when the pipeline might be restarted.
More than 200 people in Anchorage and the North Slope were working on the problem.
The leak was discovered Saturday morning by a crew that found oil in the basement of Pump Station 1. The pump station is the last stop before oil is sent into the main line and to the marine terminal in Valdez for West Coast delivery.
Dennis McLerran, regional administrator for the Environmental Protection Agency, said in a statement late Monday that the leak remained contained to the pump station.
Vacuum trucks over the weekend sucked up between 378 and 420 gallons of oil from the pump station basement. Tom DeRuyter, the on-scene coordinator for the Alaska Department of Environmental Conservation, said Monday there was still a small amount of oil trickling into the building.
The leak occurred in a particularly complex area of piping. The suspect pipe is one of several encased in concrete.
It isn't known whether oil has been released into the ground.
The most recent lengthy shutdown was last May after a storage tank overflowed at one of the pump stations. That shutdown lasted for 79 hours and 40 minutes, and there were no problems restarting the line.
Alaska's oil fields account for about 13 percent of domestic production.
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