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Massive gas leak from California underground storage reservoir causes 1,800 families to relocate

18 December 2015

The Aliso Canyon Storage Field near Los Angeles has been leaking 65 metric tonnes of gas an hour for nearly two months, and the leak is not expected to be fixed for at least another three months. The California Air Resources Board says this is a quarter of the state’s total emissions of methane, a greenhouse gas 70 times more potent than carbon dioxide.

Infrared image of the methane leak from Aliso Canyon - Image: EDF
Infrared image of the methane leak from Aliso Canyon - Image: EDF

The Federal Aviation Administration recently banned low-flying planes from flying over the site since their engines could ignite the gas.

Over 1,800 households had been temporarily relocated by December 16, and many of those affected are signing up to class action suits against reservoir operator Southern California Gas Company (SoCalGas) alleging health problems from the gas, according to local media. The strong smell of the mercaptan added to the natural gas is ubiquitous in the affected area and doctors say many are complaining of breathing difficulties and general ill-health. 

Aliso Canyon is an abandoned oil field, one of a dozen used for gas storage in California, with a capacity of around 2.5 billion cubic metres of gas.

On October 23, workers noticed the leak at a 40-year-old well, which did not respond to the usual methods to block the leak. As a result, SoCalGas began drilling a relief well on December 4 to intercept the steel pipe of the original well thousands of feet below ground, eventually allowing crews to pour in cement to seal it off permanently. “Relief wells are a proven approach to shutting down oil and gas wells,” SoCalGas said in a statement.

The presence of explosive natural gas adds an extra layer of complication. Any spark could cause an explosion so work is restricted to daylight to avoid the use of artificial lighting at night.

Meanwhile SocalGas has opened a new community centre in Porter Ranch to offer guidance on securing temporary accommodations, how to file a claim, and how to get free home air filtration, according to a company statement.

“We know that this situation has been frustrating and confusing for many families in the Porter Ranch community, and we apologize. Our new Community Resource Center will provide another way for them (area residents) to get the information they need,” said Gillian Wright, vice president of customer services for SoCalGas.

“We share everyone’s concerns about this leak’s ongoing impact on the community and the environment, and we are working as quickly and as safely as possible to stop it.”

The gas company also has created a website,, to provide updates on the relief well progress, air quality monitoring, community resources and other relevant information.

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