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Southern California Gas Co. says it has sealed the leak at its Aliso Canyon facility.

It took four months of complicated work, including drilling a relief well and clogging the bottom of the leaking well, which lies about 500 feet underground, with cement, but California’s methane nightmare seems to be over. Initially detected on October 23, the leak has caused over 80,000 metric tons of methane to leach into the air surrounding SoCal’s natural gas storage facility in Los Angeles County, increasing the state’s output of that greenhouse gas by 25 percent each day the leak continued. 

Action from the utility and state and local regulatory bodies has been slow: Governor Jerry Brown declared a state of emergency on January 6, the regional air quality board sued SoCal Gas for negligence 20 days later, and the county filed criminal charges against the utility company only last week. In that time, thousands of residents in the nearby community of Porter Ranch were relocated or have applied to be relocated, complaining of nosebleeds, headaches, and other ailments caused by the leak. 

Initially, SoCal Gas and the city agreed residents would return to their homes 48 hours after the leak is plugged (the utility is paying for alternative housing). That number has now been increased to eight days. On Tuesday a county official plans to introduce a motion to extend that time to 30 days.