Porter Ranch residents informed of brief surge in methane levels at Aliso Canyon gas storage facility

Southern California Gas Company’s Aliso Canyon methane gas storage facility near Porter Ranch neighborhood in the San Fernando Valley in January.
(Jae C. Hong/Associated Press)

Methane levels briefly surged Friday night at the Aliso Canyon gas storage facility in the San Fernando Valley, prompting Southern California Gas Co. to notify nearby residents in Porter Ranch.

The company sent out the notice late Friday night, saying that increased levels of methane had been found earlier that evening on two fence-line monitors along the facility border.

“The brief elevated methane levels lasted about 20 minutes and do not present a health or safety risk to the community,” the SoCalGas notice said. “These elevated readings are related to planned venting associated with maintenance work being conducted at the facility.”

The company said the work was being done as “part of the final stages of a project to upgrade the compressors at the facility” and that it had notified state and local agencies about the methane levels.


The notifications failed to reassure Matt Pakucko, president and co-founder of the activist group Save Porter Ranch. “If they knew ahead of time … why didn’t they tell us ahead of. time?” Pakucko said, casting doubt on the company’s explanation.

SoCalGas spokesman Chris Gilbride said in an email that “while the maintenance was planned last night, the elevated readings at the fence-line were not anticipated.’'

Methane levels, which normally hover around 2 parts per million in the Aliso Canyon area, temporarily reached 56 parts per million at one of the two monitoring points, according to readings shared online.

“Importantly the brief increase in readings did not present a hazard to the community,” Gilbride said.


Two years ago, the biggest methane gas leak in U.S. history happened at the Aliso Canyon facility, spurring the evacuation of thousands of people from surrounding neighborhoods. Many residents complained of nosebleeds, headaches and nausea.

SoCalGas spent hundreds of millions of dollars to relocate residents and handle other costs related to the leak. Earlier this year, it agreed to pay $8.5 million to settle a lawsuit from the South Coast Air Quality Management District and had earlier committed $4 million to settle criminal charges from the district attorney.

The company resumed gas injections at the controversial site this summer after an appeals court lifted a temporary ban on operations. Los Angeles County had sued the company to try to stop it from restarting those injections.

Environmental and neighborhood activists like Pakucko have continued to call for the facility to be permanently closed.

Twitter: @AlpertReyes

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