An estimated 100 gallons of sodium hypochlorite was released into the environment through a broken pipe around 1 p.m. Wednesday, May 3, at the Sandy Wastewater Treatment Plant, 33400 Jarl Road.
The pipe is buried about 5 to 6 feet below the ground and evidence of the break was not visible from the surface. The sodium hypochlorite missed with groundwater and traveled through a series of perforated pipes, eventually entering the plant's on-site storm drainage system and Tickle Creek.
Liquid sodium hypochlorite is a stronger concentration of household bleach, with 12.5 percent chlorine compared to 5 percent chlorine found in bleach. According to Mike Walker, public works director, the incident was a "minor release."
Upon learning of the release, the treatment plant staff shut off the broken pipe and plugged the storm water outfall to prevent further release of sodium hypochlorite into the creek. All groundwater flow from the storm drain system was diverted to a treatment plant by 4:30 p.m.
The Department of Environmental Quality and the Oregon Emergency Response System were notified and the city and contract operations staff are cooperating with these agencies to assess the impacts to the environment.