More than 300,000 gallons of partially treated wastewater has spilled from a leaking pipeline at the Sausalito-Marin City Sanitary District wastewater treatment plant into the San Francisco Bay.
The leak continued through Wednesday and spilled 300 gallons per minute, general manager Bob Simmons said.
The tide at the spill site is expected to recede enough to allow repairs to the 2 1/2-inch hole in the 23-year-old pipe, Simmons said.
The leak was reported at about 1 p.m. Tuesday at the plant, just south of Sausalito at Fort Baker, said Simmons.
Rebecca Ng, the Deputy Director of the Marin County Envirnonmental Health Division, said, "We're concerned with the health of people who may want to swim and boat. We would advise people to stay out of the water for at least several days."
They've posted warning signs along the shoreline and have closed the fishing pier at Horshoe Cove.
They are advising folks who want to get in the water to stay at least a mile away. They are asking boaters in the area to have minimum contact with the water. Ng says if the spill is contained by 1 p.m. they're estimating 400,000 gallons of partially treated sewage will have been released into the bay.
The sanitary district notified regulatory agencies and hired a contractor to repair the pipeline. However, the 23-year-old pipeline sits partially in the surf and high tide prevented repairs, Simmons said.
The contractor attempted to perform a temporary repair, using a wooden plug, but determined it could exacerbate the problem.
Simmons said the contractor would attach a saddle clamp to the pipe Wednesday morning.
The pipe was leaking about 12,000 gallons an hour, according to Simmons.
The partially treated wastewater spilling into the bay has not been secondarily treated or disinfected, Simmons said.
The official cause of the leak remains under investigation, but Simmons said the contractor determined it may have been due to a defect when it was originally installed, according to Simmons.
The sanitary district is working closely with Marin County health officials and water samples will be taken over the next few days, Simmons said.
"We've had spills," Simmons said of his time with the sanitary district. "I don't think we've had any spills at the treatment plant of this magnitude," he added.
The sanitary district serves 18,000 customers.