California Officials Delay Plans to Mitigate Massive Gas Leak

Southern California air quality officials on Saturday delayed plans to capture and burn off natural gas leaking from an underground well near an affluent Los Angeles neighborhood, citing the possible risk of a fire.

The move came at a public hearing where Porter Ranch residents, many of whom have been displaced or sickened by the methane leaking from the underground storage well, expressed frustration over the failure of the state or the utility, Southern California Gas Co, to stop the leak.

The leak was first detected on Oct. 23 at an underground natural gas field in Porter Ranch, which is home to more than 30,000 people. Thousands of residents had to move over the holidays, with the company underwriting their temporary housing.

Officials from Southern California Gas, a division of Sempra Energy (SRE), said they expected to stop the leak in late February or March.

State officials have said the leak accounted at its peak for a fourth of California's 20 million metric tons a year in greenhouse gas emissions from methane.

The cause of the leak is believed to be a broken injection-well pipe several hundred feet beneath the surface of the 3,600-acre (1,457-hectare) field.

Nearby residents have complained of such ailments as headaches, nausea and respiratory irritation from mercaptans, the odorants added to natural gas, according to Los Angeles County health officials. The officials have said past studies found no long-term health effects from mercaptans.

The South Coast Air Quality Management District was expected at Saturday's hearing to sign off on an order instructing Southern California Gas to come up with a plan to capture and treat the escaped gas in the interim.

The order originally required the utility to dispose of the gas by burning it, but district officials said at the hearing that safety concerns from local and state agencies required them to put that plan on hold.

"They have expressed concern about not being familiar with this type of gas collection and capture," said Mohsen Nazemi, a deputy executive director for the regulator. "It's a very unusual circumstance."

Such a process risked "additional fire" if the gas is blown downwind to nearby incinerators, Nazemi added.

Residents who attended the hearing said they were angry that a decision had been delayed since they had been forced to leave home for months.

(Reporting by Phoenix Tso; Editing by Dan Whitcomb and Lisa Von Ahn)