SEATTLE -- The Washington Department of Ecology says the amount of sewage overflow that forced the beach to close at Golden Gardens Park is about 165,000 gallons.
Seattle Public Utilities says the overflow was caused by a blockage in the sewer system north of the park.
"The blockage was caused by tree roots and materials like wipes which, despite what might be on their labels, are not 'flushable,'" SPU said.
Signs have been posted at public access points, and the public is advised to avoid contact with the water in the affected area.
Swimming in the contaminated water can cause gastroenteritis, skin rashes, upper respiratory infections, and other illnesses, according to health officials. Children and the elderly may be more vulnerable to waterborne illnesses.
The overflow has been stopped, but water samples showed high levels of bacteria.
The water will be closed to swimming and fishing until further notice.