Azerbaijan National Academy of Science

Over the past three months, more than 87,000 metric tons of methane, a potent greenhouse gas, have spewed into the atmosphere from a leak in a failed natural gas well in Southern Calif­ornia. Southern Calif­ornia Gas Co., the well’s owner, announced Jan. 18 that it hopes to stop emissions from the Aliso Canyon Storage Facility in northern Los Angeles by late February.

But the leak, one of the largest of its kind in U.S. history, will have a lasting environmental impact on local, state, and perhaps federal levels.

More than 2,500 households in the Porter Ranch neighborhood near the facility have been forced to relocate because of noxious odors from pollutants such as mercaptan, which is added to odorless natural gas for safety purposes. Some recent reports have also suggested that SoCalGas may have underestimated the amount of benzene, a carcinogen, which has been released during the leak. Timothy O’Connor, director of the Calif­ornia oil and gas program at the Environmental Defense Fund (EDF), an environmental advocacy group, says it may be difficult to know how much benzene exposure has occurred because of a variable emissions rate and a lack of extensive testing when the leak first started. Although both benzene and mercaptan are harmful in high doses, little is known about the health effects of long-term, low-dose exposures.

On Jan. 6, Calif­ornia Gov. Jerry Brown (D) declared a state of emergency and ordered increased regulations and inspections on gas facilities in the state. The leak could thwart Calif­ornia’s ambitious goals to cut greenhouse emissions statewide.

In addition to footing the bill for relocating people and addressing the leak, SoCalGas faces lawsuits from the city and local residents claiming that the company failed to properly maintain its facility.

Starting in mid-November, SoCalGas tried to plug the well but failed. So the gas company began drilling a relief well on Dec. 4, expecting to reach its target, 2,600 meters below the surface, in February. The company also scuttled a risky proposal to divert and incinerate some of the methane.

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