From WikiPedia: at Aliso Canyon gas leak
The Aliso Canyon gas leak (also called Porter Ranch gas leak and Porter Ranch gas blowout) was a massive natural gas leak that was discovered by SoCalGas employees on October 23, 2015. Gas was escaping from a well within the Aliso Canyon's underground storage facility in the Santa Susana Mountains near Porter Ranch, Los Angeles. This second-largest gas storage facility of its kind in the United States belongs to the Southern California Gas Company, a subsidiary of Sempra Energy. On January 6, 2016, Governor Jerry Brown issued a state of emergency. The Aliso gas leak's carbon footprint is said to be larger than the Deepwater Horizon leak in the Gulf of Mexico. On February 11, 2016, the gas company reported that it had the leak under control. On February 18, 2016, state officials announced that the leak was permanently plugged.
An estimated 97,100 tonnes (95,600 long tons; 107,000 short tons) (0.000097 Gt) of methane and 7,300 tonnes (7,200 long tons; 8,000 short tons) of ethane were released into the atmosphere, 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. By comparison, the entire rest of the South Coast Air Basin combined emits approximately 413,000 tonnes of methane and 23,000 tonnes of ethane annually.
porter ranch gas leak LA Times has A huge list of articles on the subject.
Methane detected near shuttered Porter Ranch gas well Methane was detected Saturday seeping out of the soil near the plugged natural gas well at Aliso Canyon responsible for the largest natural gas leak in the nation, Southern California Gas officials reported.
SoCal Gas To Pay $4M Fine For Aliso Canyon Gas Leak Los Angeles County District Attorney Jackie Lacey announced today a $4 million settlement with Southern California Gas Co. that will require the utility to pay the maximum fine authorized by law and to adopt safety measures beyond those required by federal and state laws at its Aliso Canyon Natural Gas Storage Facility.
Lawsuits, costs continue to mount in gas leakTwo years after a natural gas well blew open near Porter Ranch, the cost of the nation’s largest-ever accidental gas leak continues to mount. So do the number of lawsuits it's triggered, according to Southern California Gas Company's third quarter report, released this week.The cost of the Aliso Canyon gas leak is up to $841 million as of Sept. 30. That’s up $9 million dollars over the last three months, the report said. One of the expenses stemming from the leak is an independent study to pinpoint why the well failed.
October 14, 2017 - Daily News - Porter Ranch residents exposed to Aliso Canyon gas leak have uranium, lithium and other chemicals in their bodies, health study shows While the leak was deemed unprecedented, no one can point to past studies or research on the health effects of such an exposure to answer residents’ lingering health questions.
Nordella said different patients were exposed to different levels for different times, and it won’t be clear how people are affected unless researchers follow them for at least three to five years.
Jan 5, 2017 - Los Angeles Daily News - SoCalGas warns of natural gas shortage to meet surging demand, as Aliso Canyon wells remain closedMore than a year and a half after the Aliso Canyon natural gas storage facility caused more than 100,000 tons of methane to leak into the atmosphere – amounting to be our nation’s largest-ever gas leak, California regulators continue to labor away at improving the rules that could prevent another gas storage disaster.
July 7, 2017- EDF Blog - The Secret Sauce For Preventing Another Aliso Canyon-Sized Gas Leak In California “A smart and successful natural gas storage program must include proper risk management and emergency response planning. That’s a lot of the secret sauce right there. These plans should outline the risks each facility faces, the practices and procedures for reducing those risks, and the playbook for dealing with problems. ”