SAN FRANCISCO, California (CNN) -- Nearly 3 million gallons of sewage spilled into San Francisco Bay when a pump failed at a waste treatment facility, the Marin County Sheriff's Department told CNN on Friday.
Attempts are being made to contain Thursday night's 2.7 million-gallon sewage spill.
The 2.7 million-gallon spill occurred Thursday night.
A pump failed at the South Marin Sanitation District's waste treatment facility in the town of Mill Valley, said Lt. Doug Pittman.
The waste was released into Richardson Bay, an inlet of the large bay on the east shore of Marin County, he said. See the spill from the air »
The sewage and storm water was partially treated, according to Greg Renick of the California Office of Emergency Services.
In addition to the pump failure, he said, an alarm that would have alerted workers at the facility to the spill also failed.
The accidental release occurred between 5:30 and 8:30 p.m. Thursday, according to a statement from Marin County's emergency operations center. But the Sewerage Agency of Southern Marin didn't report it to the state until 11:16 p.m., Renick said. The state Office of Emergency Services notified local offices in the bay area within an hour of receiving the report, he said.
The Marin County Department of Environmental Health was conducting tests Friday to determine how far the contamination had spread, Pittman said. Boaters were being warned to avoid the Richardson Bay area, and residents were told to avoid contact with the water.
The California Department of Fish and Game has had a boat and personnel on the water since early Friday, and has found no sign of sick or distressed wildlife resulting from the spill, agency spokesman Steve Martarano said.
CNN's Chuck Afflerbach contributed to this report