Nine oily mallard ducks and six dead ducks had been recovered as of Monday after a feedlot tank leaked oil near Sunnyside, according to the Washington State Department of Ecology.
Efforts will continue this week to catch birds contaminated by the spill, including a planned operation to capture a gaggle of contaminated domestic geese living in the wild.
Work should start this week to clean the contaminated birds after they have been given some time in captivity to rest and recover.
About $500,000 has been spent since the spill was discovered March 1, with the response costs continuing to rise, said Ecology spokeswoman Lisa Copeland.
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Over the weekend the oil in a ditch near the spill site was cleaned and work continued to clean the Sulphur Creek Wasteway, which had released oil into the Yakima River. A sheen was seen as far downriver as Prosser.
Work also continued Monday to try to determine the oil’s path from the spilled tank to the irrigation canal. The investigation into the volume of oil spilled and the cause is continuing.