A broken pipeline spewed oil onto Pyramid Lake, spreading black liquid across an estimated eight acres of the water surface on a major reservoir that supplies Southern California.
Los Angeles County Fire Department crews first by hand and then with bulldozers created a dike to stop the crude oil that flowed out of the broken 14-inch line east of Interstate 5, then into a culvert beneath the highway toward the lake.
"As a precaution, we stopped the flows from Pyramid to Castaic (Lake)," Rich Sanchez, chief of State Water Project operations, said after the oil spill was discovered. "Pyramid Lake is one of our holding reservoirs. There's plenty of water (in reserves). There won't be any interruption to water service."
It was not clear what caused the 14-inch Pacific Energy Co. pipeline to rupture sometime after 1 p.m. Wednesday.
The pipeline is one of three -- another also carries oil and a third carries natural gas -- that parallel Interstate 5 through hillsides that suffered extensive damage during February's heavy rains.
Large mudslides left sections of the underground pipelines damaged and exposed, forcing Pacific earlier to cap a section of its damaged line and temporarily reroute it. Pyramid Lake's visitors center has been closed by landslides that state officials say continue to move.
It was not clear how much oil found its way into the water.
Pacific Energy Co. officials confirmed that the pipeline broke and said about 42,000 gallons of oil were lost, according to county Fire Inspector John Mancha. Sheriff's officials said they were told the oil slick covered about eight acres of the 1,297-acre lake.
Created by damming Piru Creek with a 400-foot-tall dam completed in 1973, the reservoir is filled with Northern California water brought south by the west branch of the California Aqueduct. Anglers fish its water for bass, trout, bluegill and other fish.
Pyramid and Castaic Lake downstream are owned by the California Department of Water Resources. The water goes to Santa Clarita and other Southern California communities. Los Angeles has its own aqueduct system that brings water from the eastern Sierra Nevada.
Fire officials said firefighters were on the scene by 2 p.m. Crews worked to create a dam on the hillside above the highway until bulldozers arrived.
Representatives from the state's departments of Fish and Game and Water Resources and the U.S. Forest Service were on scene to assess the damage and plan clean-up efforts.