Alki Beach in West Seattle and other Puget Sound beaches are closed after millions of gallons of sewage flowed into the water.
The Washington state Department of Ecology says early Friday the West Point Wastewater Treatment Plant released an estimated 3 million gallons of untreated sewage over about 27 minutes, after backup pumping systems failed during power disruptions.
On Thursday, officials say a separate power failure at the Renton Wastewater Treatment Plant resulted in potentially limited disinfection of treated wastewater. That plant discharges into Puget Sound northwest of Duwamish Head in Seattle.
Ecology is investigating both incidents as discharges that would violate the state's water quality permits for the facilities.
The other beaches closed include those at: Carkeek Park, Discovery Park, Elliot Bay Marina, Golden Gardens Park, Myrtle Edwards Park, Magnolia Tidelands Park, Port of Seattle Terminal 91 and Seacrest Park.