A plugged sewer line caused raw sewage to flow into Ballona Creek in West Los Angeles and on into the Pacific Ocean Thursday, prompting officials to close beaches to swimming, Bureau of Sanitation officials said.
City workers temporarily cleared the line Thursday evening, but the blockage reappeared and sewage began flowing into the creek again shortly after 7 p.m., bureau spokeswoman Anna Sklar said.
Officials said a sewer plate had been removed from a pipeline, but they could not determine whether that was the work of vandals who might have dumped something into the pipeline. Sklar said pressure within the line could have blown the cover plate.
Preliminary water samples taken Thursday indicated extensive contamination in the creek itself, as well as in the ocean just south of Marina del Rey, Sklar said.
"We're talking minimally hundreds of thousands of gallons, possibly even millions," she said.
4Los Angeles County health officials were notified of the contamination and posted signs warning of the contamination on beaches from the Venice Pier to Grand Avenue in El Segundo, she said.
"We really don't know what plugged the 45-inch line," Sklar said.
Biologists from the Hyperion treatment plant laboratory took samples at the discharge near the intersection of Cadillac and Burchard avenues as soon as the sewage overflow was discovered, Sklar said. They will continue monitoring the contamination for the next several days, she said.