The mechanical failure of a pump in a King County pump station along the Black River in Renton resulted in the release of an estimated five to 10 gallons of motor oil into the river early Saturday, April 20.

The pump failure occurred at the County’s Black River Pump Station late at night on April 19 or early in the morning of April 20. Motor oil spilled from the damaged pump into the Black River.

King County contacted the Washington Department of Ecology (DOE) and a spill-response contractor, which installed oil containment booms upstream and downstream of the pump station on the Black River on Saturday morning.

King County, DOE and the spill-response contractor all took water samples from the Black and Green rivers, including downstream of the confluence of the Black and Green rivers at Fort Dent Park Tukwila.

The samples will be tested as soon as possible, with results expected in two to three days. Additional water samples will be collected early next week.

The Black River Pump Station regulates flow of water from the Black River drainage basin into the Green River, and serves to block high flows on the Green River from flooding up into the Black River and Springbrook Creek watersheds.