Officials say the spill is 99% contained after a pipe broke and released partially treated waste into the body of water

This article is more than 11 years old

This article is more than 11 years old

A broken pipe gushed at least 500,000 gallons of partially treated sewage into San Francisco bay by Wednesday afternoon as Sausalito, California sanitary plant officials continued to try to contain the spill more than 24 hours after it was spotted.

Bob Simmons, general manager of the Sausalito-Marin city sanitary district, said shortly after 2pm that the spill was 99% contained.

Workers in wetsuits were trying to seal up a metal ''saddle'' placed around the 24-inch-wide pressure pipeline resting along the shore below the Fort Baker treatment plant to redirect wastewater back into the plant.

The spill was first spotted at about 1pm on Tuesday at the district's treatment plant in the Golden Gate national recreational area.

After several hours of unsuccessful attempts to plug the 2-inch hole before the pipe was submerged in tide water, the leak was allowed to continue until work could continue on Wednesday morning.

''This situation is unfortunate,'' said Simmons, noting the district's largest previous spill was 63,000 gallons in January 2008.

Simmons said the hole likely was due to corrosion of the 23-year-old pipe constantly exposed to tide water.

He said officials didn't have the option to shut off flow to the broken pipe because all pipes in the small plant on the steep hill just south of downtown Sausalito were interconnected and under pressure.

''This treatment plant has some challenges that most plants don't have,'' Simmons said.

Warning signs indicating sewage contamination remain posted along nearby shoreline including Sweet's Beach, Horseshoe Cove, Schoonmaker Point Marina and Rodeo Beach. City officials in Sausalito, Tiburon and Belvedere have also posted signs along their shores.

Becky Ng, interim deputy director of the Marin county environmental health services, recommended people stay out of the water in the surrounding area.

Officials expected test results of initial water samples to be available today.

The district was one of nine southern Marin sewage agencies ordered to submit improvement plans to the environmental protection agency last year in response to the federal agency's orders in April to fix chronic problems including spills, sewer maintenance and a network of aging pipes.

The orders followed federal inspections of the districts in August and October 2007.