State of emergency declared in California over three-month methane gas leak

The Southern California Gas Company says that may take until late March to resolve the problem

The leak from a well in the Porter Ranch neighbourhood, pictured above, is not expected to be fixed until February or March (AFP)

The Governor of California has declared a state of emergency over a gas leak from an underground methane facility in greater Los Angeles, which environmentalists say is generating daily emissions equivalent to six coal-fired power stations.

Jerry Brown called for “all necessary and viable actions” to be taken to plug the leak, which was first detected on 23 October at a vast underground gas storage system close to the community of Porter Ranch, around 30 miles from the centre of LA.

The Southern California Gas Company (SoCalGas) says more than 2,000 nearby households have taken up its offer to fund their temporary relocation, after residents experienced headaches, nausea, dizziness and shortness of breath.

The leak is both a local public health hazard and an environmental crisis of massive proportions, expelling an estimated 110,000lb of gas into the atmosphere per hour: about a quarter of the state’s daily methane emissions. Methane is a significantly more potent greenhouse gas than CO2.

Tim O’Connor, California director for the Environmental Defence Fund’s oil and gas programme, told The Independent: “In terms of aggregate greenhouse gas emissions, it is greater by far than the BP Deepwater Horizon disaster.”

Methane is non-toxic and odourless, but is injected with trace amounts of other chemicals, known as mercaptans, to make it detectable by smell. In spite of residents’ health complaints, experts insist that in their current quantities, mercaptans pose few long-term medical risks.

The leak stems from a broken pipe approximately 500ft underground, but after several failed attempts to plug it from the surface, SoCalGas is drilling a relief well to the natural gas reservoir some 8,500ft below the surface, from which the leaking well can be sealed at source with heavy fluids, mud and concrete. The company says that may take until late March.

Governor Brown has ordered new safety and inspection regulations for all of California’s natural gas storage facilities.