The state Department of Ecology is investigating the sewage treatment failures at King County’s two largest sewage treatment plants that led to beach closures across Puget Sound and a “no-contact” advisory for the eastern shoreline of Bainbridge Island for three days last week.

Kitsap Public Health District has issued the “no-contact” advisory Friday, July 19, and it ran through the weekend.

Ecology officials said the West Point Wastewater Treatment Plant in Seattle released an estimated 3 million gallons of untreated sewage for approximately 27 minutes early on the morning of July 19.

Backup pumping systems failed during power disruptions at the plant, officials said, and the system diverted incoming wastewater to an emergency outfall near North Beach in Discovery Park.

Earlier, on Thursday, July 18, a different power failure at King County’s Renton Wastewater Treatment Plant led to a “potentially limited disinfection” of treated wastewater, officials said.

The treatment breakdown lasted approximately 50 minutes. The Renton wastewater plant discharges into Puget Sound, about two miles offshore, northwest of Duwamish Head in Seattle.

Ecology is investigating both incidents as unauthorized discharges that would violate the Washington state’s water quality permits for the facilities.

The agency anticipates taking necessary enforcement actions after its full investigation, officials said.

After the second sewage spill last week, Bainbridge residents were advised to avoid contact with the water along island’s east shoreline because modeling performed by King County, and reviewed by the Washington State Department of Health, showed there was potential for sewage to impact the area. Residents in Indianola were warned, as well.