How Do You Stop the Biggest Gas Leak Ever?

Steve Conley got the call early on Nov. 5. A natural gas storage well was leaking methane into the air at Aliso Canyon, near a Los Angeles suburb, and no one knew just how bad it was—could he get a read on it? Conley, an atmospheric scientist and a pilot, rushed to a small airport northeast of Sacramento. He’s flown more than 1,500 hours measuring emissions over oil and gas operations in one of his two single-engine Mooneys. Tubes mounted on each Mooney’s right wing suck air into two chemical analyzers stored in the luggage compartment. Soon Conley was soaring south across California’s Central Valley.

The leak had been spewing for about two weeks. Southern California Gas Co., the subsidiary of Sempra Energy that owns the facility at Aliso Canyon, had tried and failed to kill it. The previous night, homeowners from the nearby neighborhood of Porter Ranch had gathered to rail about the rotten-egg smell taking over their community. Tim O’Connor, a lawyer at the Environmental Defense Fund (EDF), attended the meeting, and feared the leak could be big enough to threaten not only the local community but also the earth’s climate.