Dam Owner Guilty in Field Turf Pollution of Washington River

Pieces of rubber from Astroturf used in a retrofit of Electron Hydropower Project are found on the banks of the Puyallup River 14 miles down from the dam. Steve Ringman/The Seattle Times via AP

SEATTLE—A company that operates a century-old hydroelectric dam near Mount Rainier National Park and its chief operating officer each pleaded guilty to a single criminal count Monday in connection with a spill of synthetic field turf and the tiny rubber particles used to make it into the Puyallup River in 2020.

The company, Electron Hydro LLC, also will pay $1 million that mostly will go to projects to restore salmon habitat.