Increased methane levels reported at SoCalGas’ Aliso Canyon facility near Porter Ranch

Elevated methane levels were observed Friday night, Dec. 1 at the Aliso Canyon natural gas storage facility near Porter Ranch, according to a memo by the Southern California Gas Co.
The gas company sent the notice late Friday to residents who live near Aliso Canyon after SoCalGas Co. operators noted an increase in methane levels on two fence-line monitors along a border with the community.
The elevated methane levels lasted about 20 minutes, according to the memo.
A SoCalGas official said the incident did not create a hazard.
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“These elevated readings are related to planned venting associated with maintenance work being conducted at the facility,” the notice said. “The maintenance is part of the final stages of a project to upgrade the compressors at the facility. SoCalGas has also provided notifications to the relevant state and local agencies.”
It’s been two years since SoCalGas’ Aliso Canyon facility became the site of a massive natural gas leak from 2015 to 2016 that released more than 100,000 metric tons of methane over nearly four months, sickened thousands of residents and forced many of them to relocate from the area.
“While the maintenance was planned last night the elevated readings at the fence-line were not anticipated,” said SoCalGas spokesman Chris Gilbride. “Importantly the brief increase in readings did not present a hazard to the community.”
Methane levels reached 56 parts per million Friday night. Two parts per million is the background level throughout Los Angeles, but a reading higher than that is not necessarily a point of concern; it would depend on how high and how long the level is elevated, Dave Clegern, a spokesman for the California Air Resources Board, previously told the Daily News.
If the monitor reading is “at the fenceline and is high enough and lasts long enough (hours or days), it could be an issue,” he said.
Staff writer Brenda Gazzar contributed to this story. 
 
Source: Oc Register