ANCHORAGE (AP) -- The source of several recent small spills of old crude oil in Cook Inlet has been narrowed to one of two underwater pipelines servicing Unocal's Dillon production platform.
A survey flight with response workers and government regulators early Tuesday morning pinpointed an oil patch surfacing about 200 yards off East Forelands near Nikiski in the same corridor as two 8-inch lines, according to Unocal and the state Department of Environmental Conservation.
The company suspected that the leak was coming from an abandoned oil pipeline that had been capped since last fall -- and not from an active natural gas pipeline currently undergoing maintenance and testing.
''We hate to rule out anything at this point,'' said Unocal spokeswoman Roxanne Sinz. ''We're still investigating everything.''
In an attempt to identify the broken line, Unocal and response teams planned to pressurize the gas line, then fly over the scene and look for bubbles. What happens depends on what the teams find out, said Leslie Pearson, the state's spill coordinator for the area.
Four sheens have been spotted in the vicinity since Friday night, amounting to an estimated 170 to 180 gallons of weathered crude oil, Pearson said. The oil had an old silvery appearance and did not produce the rainbow sheen associated with fresh oil.
''There's always some kind of environmental concern when you have releases like this,'' she said. ''But there haven't been any kind of wildlife impacts that have been observed.''
That oil pipeline had been shut down since failing in November 1999, when it spilled about 460 gallons of crude oil. Last fall, the company removed a 20-foot section containing the break and capped the ends, Sinz said.
The condition of Cook Inlet's aging offshore pipeline system, much of it laid in the 1960s, has been an increasing source of concern to environmental regulators as well as industry.
In February, a quarter-inch diameter hole in a pipeline from Unocal's Dolly Varden platform spilled two to 20 gallons. Since then, the company has launched an internal project to analyze the integrity of its pipelines in Cook Inlet, Sinz said.
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