Tracking the Aliso Canyon gas leak by air

For 119 days gas spewed from a leaking well in the hills above the community of Porter Ranch. The well was permanently sealed on Feb. 18, according to the California Division of Oil, Gas and Geothermal Resources. More than 90,000 metric tons of methane, a powerful greenhouse gas, is thought to have leaked from the well, and chemicals in the gas led many local residents to temporarily abandon their homes. Reporter George Lavender talked in late January with Steve Conley, a scientist-pilot, who described the grueling work necessary to survey the plume from the air: