by Chris Mulick
A mechanical failure at the Little Goose Dam on Sunday spilled at least 35 gallons of oil into the Snake River.
Cleanup activities wrapped up Monday, and the dam resumed normal operation.
Joe Saxon, a spokesman for the Army Corps of Engineers, said as many as 125 gallons could have leaked into the river but "we don't think that much oil was spilled."
"Theoretically, it could have been up to that," he said.
Little Goose Dam, a run-of-river dam almost 30 miles north of Dayton, is operated by the Army Corps of Engineers and the 135-megawatt turbine generator that leaked will turn 30 next year.
Each of the six turbine generators in the powerhouse contains about 10,000 gallons of recycled oil, said Michael McCain, a spill responder for the state Department of Ecology who is familiar with their operation.
Sunday's failure during normal operations at Generator 6 occurred about 7 a.m. and was immediately detected.
"It was pretty obvious," Saxon said.
Several hundred gallons of oil had spilled onto the powerhouse floor before the leak was stopped. An absorbent material was spread to soak up the oil and the generator commenced operations Monday.
Outside, 35 gallons of oil were retrieved from the river. That includes 10 gallons that had drifted downstream to the Lyons Ferry area, Saxon said. An initial report to Ecology indicated a barge operator reported seeing a sheen a half-mile long.
Other coves and shorelines were inspected before cleanup activities were called off Monday.
The state Department of Ecology was notified, but the spill, based on an initial report, did not warrant sending a response team, McCain said.
He said it doesn't take much oil to make even a small spill look large.
"A quart of motor oil will cover a whole lake with a sheen," he said.
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