Massive gas leak

A leaking gas wellthat spewed vast quantities of methane into the atmosphereabove a California town has been “permanently sealed”, officials said on Thursday.The leak from the Aliso Canyon facility in Porter Ranch, near Los Angeles, had been called the biggest in America’s history andforced thousands of residents to fleeafter they suffered nausea, headaches and other symptoms."We have good news. The Division of Oil and Gas has confirmed that the leak in the Aliso Canyon storage field is permanently sealed," Jason Marshall, chief deputy director of California’s conservation department told journalists.The announcement came a week after the Southern California Gas Company (SoCalGas) said it had “temporarily” stopped the leak following a delicate operation that involved pouring cement and heavy fluids into the more than 8,400 feet deep well.Residentscomplained of a pungent sulphurous smell akin to rotten eggsafter gas began leaking from the well last October 23.Many were relocated in temporary housingand hotels after complaining of ill health.Methane leak at#PorterRanchsealed, but the damage is donehttps://t.co/abpkzmtG47pic.twitter.com/LMzdf94TBV— Heal the Bay (@HealTheBay)February 18, 2016At its worst, the leak poured 100,000 pounds of methane an hour into the atmosphere and is calculated to have increased California’s annual greenhouse gas emission by 25 per cent.The mounting crisis prompted both Los Angeles county andJerry Brown, California’s governor, to declare states of emergencyafter initial efforts at plugging the leak failed.Los Angeles county’s district attorney office pressed four criminal charges against SoCalGas this week, claiming the company delayed for several days before reporting the release of hazardous materials and air contaminants. The company has pleaded not guilty to the charges.Life can return to normal in Porter Ranch, but the damage to the environment has been done.https://t.co/HLdfV6cidmwith@matthewferner— Lydia O'Connor (@lydiaoconnor)February 18, 2016Residents were notified by text on Thursday that they have eight days to move out of the temporary accommodation which SoCalGas has paid for.More than 6,000 families have vacated their homes, some of them moving to private rental accommodation, others to hotels and motels.However, state air quality officials have urged a longer timetable amid concerns that pollutants - including hydrogen sulphide, mercaptan and benzene, a known cancer agent - may linger in the atmosphere for longer.The leak is expected to prompt aflood of legal actions and compensation claimsfrom residents aggrieved at thedisruption to their lives and the damage to property valuesin an area previously coveted for its clean air. Businesses say trade has been heavily hit.#PorterRanchgas leak is finally sealed for good; those responsible must be held accountable.https://t.co/Fee990vNwx— Adam Schiff (@RepAdamSchiff)February 18, 2016Pressure is building for the storage depot -the largest natural gas facility west of the Mississippi - to be closed, an outcome SoCalGas say would badly disrupt domestic energy supplies in the Los Angeles area.