The months-long natural gas leak that forced thousands of Los Angeles residents from their homes ranks as the largest known accidental methane release in US history, equal to the annual greenhouse gas emissions of nearly 600,000 cars, scientists reported on Thursday. At its peak, 60 tons per hour of natural gas was spewing from a ruptured underground pipeline at the Aliso Canyon storage field, effectively doubling the methane emissions of the entire Los Angeles metropolitan area, Reuters reported. Published in the journal Science, the study represents the first comprehensive effort to quantify a gas leak that made scores of people ill and prompted the temporary relocation of more than 6,600 households from the northern Los Angeles community of Porter Ranch at the edge of the gas field. The damaged injection well discharged a total of 97,100 tons of methane into the environment from the time it was first detected on October 23 until it was plugged earlier this month. Methane, the chief component of natural gas and a far more potent greenhouse agent than carbon dioxide, persists in the atmosphere for 10 years.
