SILVERTON, Ore. (AP) -- A Silverton, Ore., fire official says three men collapsed from carbon monoxide poisoning at a dairy after using a gasoline-powered pressure washer inside a large, closed cooler.

Fire Capt. Ed Grambusch says firefighters and medics responded to Mallorie's Dairy on Monday to find one man unconscious and two others able to talk. The three had collapsed just outside the building where they had been working.

Two men, including one in his 20s and one in his 60s, were taken to Silverton Hospital. A third man, in his 50s, was taken to Salem Hospital. All were reported in serious condition.

The fire spokesman says firefighters measured the carbon monoxide level inside the storage cooler at 232 parts per million. Levels higher than 100 parts per million are considered dangerous.

Silverton is northeast of Salem in Marion County.

Mallorie's announced earlier this month that it was was shutting. The dairy has sold its 3,000 cows -- including 1,600 milkers -- to a Texas dairy and will shut down by the end of the month.

Copyright 2011 The AP.