After one of its natural gas storage wells blew out and caused the biggest methane leak in United States history, the Southern California Gas Company has agreed to pay $119.5 million to settle city, county, and state claims against it, the Los Angeles Times reports. SoCal Gas has already paid $4 million, and agreed to pay another $8.5 million, in other settlements related to the disaster.
The leak began in October of 2015, in SoCal Gas' Aliso Canyon gas field, near the Porter Ranch neighborhood. It took the company almost four months to stop the outpouring of natural gas, during which time an estimated 109,000 metric tons of methane were released into the atmosphere. The amount was roughly the same as what the entire Los Angeles Basin emits in a year.
The leak caused symptoms such as headaches and nausea, which forced Porter Ranch residents to relocate temporarily and wasted an important energy resource. It also contributed to global warming: Although less prevalent than carbon dioxide, methane is a potent greenhouse gas. As Thomas Ryerson, a chemist with the National Oceanic and Atmospheric Administration, said just weeks after SoCal Gas finally plugged its leak in February of 2016, "One little thing going wrong has just rolled back years of emissions reduction efforts by the state of California."
SoCal Gas has committed to monitoring the Aliso Canyon field more closely as well as funding a health study of Porter Ranch residents and various climate change mitigation projects, the Times reports. Meanwhile, California banned natural gas storage wells that don't have an extra barrier to help contain leaks. But data released earlier this year shows more than 10,000 wells in 32 states have natural gas stored in single-walled, unshored pipes, researcher Drew Michanowicz wrote in the Times—just like the broken well in Aliso Canyon.