California fire: Thousands evacuate as blaze threatens underground natural gas pipeline

Officials have evacuated 4,000 people and close an elementary school after a grass fire threatened an underground natural gas pipeline in the San Francisco Bay Area.

The fire started on Wednesday in Bay Point, and was reportedly started after a power line fell, according to Chevron Pipe Line Company. That company operates the pipeline that was threatened by the fire.

The company said that it cut supply to the gas line, and was working with firefighters to help evacuate the area in case something went wrong.

"Venting of the Bay Point gas line is resulting in a loud, shrieking noise that has been described as a jet-engine-like sound emanating from the Chevron Pipeline Facility," the Contra Costa County Fire Protection District said in a tweet. "This is a normal part of the risk-mitigation process. Please do not call 911".

Fire officials said that Willow Cove Elementary School in Pittsburg would be closed on Thursday just in case something went wrong between the fire and the gas line.

About 1,400 homes were evacuated in the area.

Officials said that evacuation centres were being set up at the Bay Point Bay Area Rapid Transit station, and at a church.

Chevron indicated that the fire had come close to a valve junction for the line, and officials said that anyone having trouble evacuating should call emergency services.

The gas line company was originally contacted on Wednesday evening, and reportedly immediately shut down the gas line while sending a team to investigate the potential hazards.

The first evacuations were issued Wednesday evening at around 11pm, affecting a half mile radius around the fire.

In order to ensure that evacuation orders were received, the sheriff department sent officers to homes in the area to tell people about the danger. Residents were told to prepare to stay away form their homes overnight.