State confirms enormity of natural gas mega-leak in Southern California

Public health and climate impacts are focus of new data

November 23, 2015
Julie Dixon (916) 446-1058,
Timothy O’Connor, (916) 549-8423,

Los Angeles – The California Air Resources Board released the first official estimate  of the extent of the nearly month-long Aliso Canyon natural gas leak, showing that the rupture has discharged methane with an estimated warming impact over the next 20 years equivalent to carbon dioxide emissions of 2.6 to 2.9 million metric tons.   

While the gigantic leak is ongoing, the environmental impact based on preliminary data shows it is pumping out climate pollution with a larger 20-year warming impact than all of California’s petroleum refineries combined, or six large coal fired power plants, or roughly seven million passenger vehicles. Over the last month, the total amount of methane that has escaped has a 20-year warming impact comparable to the amount of climate pollution caused by burning more than 300 million gallons of gas, or the household energy use from over 3 million homes during this time.

“Methane may be hidden to the naked eye, but the impact of this ongoing accident on both the climate and the community is all too real,” said Fred Krupp, EDF President. “If we used technology to make this plume visible, we’d all see a giant cloud over Los Angeles County — along with a media frenzy, public outcry, and urgent government action.

Methane, the primary component in natural gas, is a potent greenhouse gas that contributes to smog formation and climate change, packing 84 times the warming power of carbon dioxide in the first 20 years it is in the atmosphere. Air sampling in the area has shown methane amounts greater than 2000 times normal, as well as recorded the presence of cancer-causing agents like benzene leaking along with the methane.                                                                                             

“Leaks on the order of Aliso Canyon are rare, but day in and day out the oil and gas industry emits tens of thousands of tons of harmful methane emissions. Yet, cutting oil and gas methane emissions is possible with some of the most inexpensive pollution controls available anywhere, for any industry. We can’t afford to ignore this issue any longer. Strong national methane policy is critical to ensure that oil and gas companies manage and monitor their facilities for methane leaks more closely,” added Krupp.

Aliso Canyon is the largest natural gas storage site in the western United States, and operates under intense pressures that can force greater volumes of gas to pump out faster. The state estimate shows between 1.67 to 1.9 billion standard cubic feet of natural gas has already been lost to the atmosphere, approximately 2% of what is stored at this facility.

“The ongoing crisis in Aliso Canyon shows how much is at risk as California’s natural gas infrastructure ages,” according to Tim O’Connor, EDF Senior Attorney & Director of California Climate. “It is also a call to action that California needs to get serious about improving oversight and regulatory measures to ensure methane emissions from the oil and gas sector stays in the pipes where it belongs.” 

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