Los Angeles-area methane leak declared permanently sealed
http://www.reuters.com/article/us-california-methane-idUSKCN0VR2HN
An underground natural gas pipeline rupture that caused the largest-ever methane leak in California has been permanently capped, paving the way for thousands of displaced Los Angeles residents to return home, state regulators said on Thursday.
The leak, which began in October and accounted for a fourth of all daily methane emissions statewide at its height, was confirmed by a series of independent laboratory tests to have been successfully sealed as of Wednesday night, officials said.
The leak originated from a broken injection-well pipe deep beneath the surface of the 3,600-acre (1,457-hectare) Aliso Canyon natural gas storage field, owned by Southern California Gas Co.
State officials said the uncontrolled release of 80,000 tons of methane, the main component of natural gas and a far more potent greenhouse agent than carbon dioxide, ranked as the largest such discharge on record in California.