Duration | October 23, 2015 | – February 18, 2016
---|---|
Location | Aliso Canyon Oil Field, Porter Ranch, Los Angeles, California |
Coordinates | 34°18′54″N 118°33′51″W / 34.31500°N 118.56417°W |
Also known as | Porter Ranch gas leak / blowout |
Type | Gas leak / blowout |
The Aliso Canyon gas leak (also called Porter Ranch gas leak[1] and Porter Ranch gas blowout[2]) was a massive methane leak in the Santa Susana Mountains near the neighborhood of Porter Ranch in the city of Los Angeles, California. Discovered on October 23, 2015,[3] gas was escaping from a well within the Aliso Canyon underground storage facility.[4] This second-largest gas storage facility of its kind in the United States belongs to the Southern California Gas Company (SoCal Gas), a subsidiary of Sempra Energy. On January 6, 2016, Governor Jerry Brown issued a state of emergency.[5] On February 11, the gas company reported that it had the leak under control.[6] On February 18, state officials announced that the leak was permanently plugged.
An estimated 97,100 tonnes (95,600 long tons; 107,000 short tons) of methane and 7,300 tonnes (7,200 long tons; 8,000 short tons) of ethane were released into the atmosphere.[7] The initial effect of the release increased the estimated 5.3 Gt of methane in the Earth's atmosphere by about 0.002%, diminishing to half that in 6–8 years.
It was widely reported to have been the worst single natural gas leak in U.S. history in terms of its environmental impact.[8][9][10]
The entire rest of the South Coast Air Basin combined, with a population of about 18 million people, emits approximately 413,000 tonnes of methane and 23,000 tonnes of ethane annually.[11] The Aliso gas leak's carbon footprint could be larger than the Deepwater Horizon oil spill in the Gulf of Mexico.[12]
In comparison, a remote sensing satellite found that the Raspadskaya coal mine is releasing 762,120 metric tons, or 832,200 short tons, of methane every year, with no remediation planned.[13]
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