Officials are investigating after failures at sewage treatment plants in Seattle have led to the spill of an estimated 3 million gallons of untreated sewage into Puget Sound.

Washington state's Department of Ecology said in a statement that the spill was due in part to power disruptions.

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"The West Point Wastewater Treatment Plant released an estimated 3 million gallons of untreated sewage for approximately 27 minutes, after backup pumping systems failed during power disruptions at the plant," their statement reads.

"The release of sewage into Puget Sound has prompted local health departments to issue several beach closures," the agency said.

Officials say there was also separate power failure on July 18 at the Renton Wastewater Treatment Plant. That incident may have resulted in some wastewater not being entirely disinfected over a nearly hourlong period.

Local officials initially listed nine beaches as closed in response to the spill, but as of 3:30 p.m. local time their list had been updated to just two beaches in Discovery Park.