Gas facility closes wells:

The largest gas storage facility in the West halted using a third of the wells pumping methane underground at high pressure just weeks after it resumed operations following a major blowout, Southern California Gas Co. said.

LOS ANGELES - The largest gas storage facility in the West halted using a third of the wells pumping methane underground at high pressure just weeks after it resumed operations following a blowout that crippled it for nearly two years.

Southern California Gas Co. said Monday it notified state regulators last month that 13 of 39 injection wells at Aliso Canyon were shut down after detecting a pressure buildup.

State regulators and the company said there were no risks to public health or safety and no release of gas into the atmosphere, but the revelation raises questions about how such a problem could crop up so soon after SoCalGas upgraded equipment, passed rigorous tests and began operating under stricter rules at the aging facility.

The state Division of Oil, Gas and Geothermal Resources said the realtime pressure readings that were required after the October 2015 blowout had led to a prompt response by SoCalGas that showed new safety requirements worked.

But Anneliese Anderle, a former inspector and supervisor at the state oil and gas division, called it an incredible failure that indicated a systemic problem.

“It’s a very high failure rate when you wouldn’t expect any,” said Anderle, who has consulted for a law firm suing the gas company. “It’s really an incredible number. Each of the 39 wells had gone through a lot of study and remediation. These were the 39 out of 114 that were their best. … It’s not good.”

SoCalGas resumed pumping gas July 31 into deep underground caverns that once contained oil in the Aliso Canyon field that sits atop a mountain overlooking the San Fernando Valley on the outskirts of Los Angeles.

The field was knocked out of commission when a blowout lasting nearly four months released the largest-known amount of methane in the nation’s history and drove thousands of families from their homes.

Many residents complained of ailments ranging from headaches and rashes to nosebleeds and nausea.

The cause of the blowout has not been determined, though a state engineer said it happened 895 feet below ground in a well more than 60 years old.