ANCHORAGE, AK -- April 23, 1996, 5:00 p.m. -- Alyeska Pipeline Service Company reported today that the source of leaking oil has been discovered at milepost 594. It appears that the oil leaked around a one half-inch threaded steel plug on the bypass line of Check Valve (CV) 92. Repairs are underway and are expected to be complete by 6:00 p.m. today. An additional measure will be taken when the CV 92 excavation is safe for welding. Since the bypass line can be isolated from the mainline while repairs are underway, pipeline throughput will be increased to normal operating levels this afternoon. Alyeska continues to work closely with state and federal agency personnel in responding to and resolving this situation.

No oil or contaminated soil has been found outside of the immediate vicinity of the pipeline. No ground water contamination has been found. All of the contaminated soil has been found 14 to 15 feet below surface level. Approximately 200 gallons of crude oil have been recovered from the bottoms of the two 36" vertical access culverts 60' feet from CV 92. An additional 250 gallons of crude oil have been recovered from the actual CV 92 excavation. Approximately 330 yards of soil contaminated with crude oil has been removed from the CV 92 excavation.

Check valves are 48" valves installed at key points in the pipeline to prevent oil from flowing backwards. There are 80 check valves in the trans-Alaska pipeline. 40 of the check valves are buried, 40 are above ground. Each valve is equipped with an 8-foot long, 6-inch diameter bypass line that is connected to the up- and down-stream ends of the valve. The bypass line can be used to equalize pressure on either side of the valve in the event of valve closure.

As part of its quality program, Alyeska will conduct a thorough analysis of this incident. The results of this analysis will include implications for Alyeska's overall valve inspection and maintenance program.

Tanker loading at the Valdez Marine Terminal has not been affected by the pipeline slowdown.

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