| NEW YORK
NEW YORK Chesapeake Energy will not resume a controversial natural gas production process in Pennsylvania until a well which blew out last week is permanently sealed and inspected, a company spokesman said Monday.
Chesapeake, one of Pennsylvania's biggest shale gas producers, last week suspended hydraulic fracturing, or "fracking", in Pennsylvania after thousands of gallons of drilling fluid used in the process spewed from a well in Bradford County after a blowout.
Fracking involves releasing natural gas trapped in shale formations by blasting a mix of water, sand and chemicals into the rock. Environmentalists say that fracking can contaminate water supplies.
"The suspension will not be lifted until we have secured the well and been able to take a look at it and make some decisions about changes we need to make," spokesman Rory Sweeney said. He declined to give a timetable for when the well will be permanently plugged.
The halt on fracking affects seven Chesapeake well sites, the company said last week.
Chesapeake used a mix of plastic, ground-up tires and heavy mud to temporarily plug the well on Thursday and is now considering its options for a permanent seal.
The blowout has fueled the fierce debate about whether fracking should be allowed to continue unabated in the United States.
Advances in drilling technology such as fracking have revolutionized U.S. energy markets, opening up the potential of vast reserves of natural gas in shale deposits.
Proponents say extracting shale gas through fracking will slash U.S. reliance on foreign oil and cut carbon emissions. President Barack Obama has made natural gas the cornerstone of his energy policy, in part thanks to the huge reserves unlocked by the use of fracking. Shale gas now accounts for 23 percent of U.S. natural gas production, rising from a negligible amount in 2004.
But environmentalists and residents, concerned that fracking can pollute water supplies, have called for increased regulation on natural gas production.
(Editing by Alden Bentley and John Picinich)