PORTER RANCH (CNS) — Officials with the Southern California Gas Co. said
two measurements taken Wednesday, Dec. 28, confirmed that the latest leak of methane from an underground gas storage facility at Aliso Canyon amounted to less than one cubic foot of gas — not enough to pose a threat to public health or the environment.
SoCalGas spokesman Chris Gilbride said the recent rains triggered a very slight release of methane previously trapped beneath the soil following a four-month methane leak in late 2015 and early 2016 that emitted 109,000 metric tons of methane and displaced at least 7,000 Porter Ranch area residents for months.
That leak at the 3,600-acre underground storage facility was not capped until early February. Scientists said it was the largest methane leak in U.S. history.
The latest leak turned up Saturday morning, Dec. 24, when SoCalGas inspectors, using infra-red camera technology, found “a very slight and intermittent observation of methane” at the SS-25 wellhead of the Aliso Canyon Storage Facility, spokesman Sergio Jimenez told City News Service.
“No anomalies have been detected through other monitoring techniques, including the fenceline monitoring system and visual inspections, and there is no discernible odor at the site,” Jimenez added.
For context, Gilbride said that a standard home pilot light on a water heater consumes about 12 cubic feet per day, more than 10 times the amount released over the past four days. He said monitoring indicates that the slight methane releases are contained to the well site, and that levels in the community remain normal.
“SoCalGas promptly notified the appropriate agencies, including the Division of Oil, Gas and Geothermal Resources, California Public Utilities Commission, and the California Office of Emergency Service, and continues to work with regulators to monitor the condition,” Gilbride said.
He added that officials with the Division of Oil, Gas and Geothermal Resources had warned of possible residual leaks when the original leak was sealed in February.
SoCalGas has requested state approval to resume natural gas injections at the site while neighbors and environmental activists want it shut down permanently.