By Edward McAllister
(Reuters) - U.S. regulators said on Thursday they will perform water tests at about 60 homes in the small town of Dimock in Pennsylvania where residents say natural gas drilling has polluted wells.
The Environmental Protection Agency also plans to deliver water to four homes in Dimock where some households have relied on trucked water since drilling by Cabot Oil & Gas began there three years ago, it said in a statement on Thursday.
The tests, which will begin in the coming days, are being carried out "to further assess whether any residents are being exposed to hazardous substances that cause health concerns," the EPA said.
The announcement represents an about turn for the EPA, which six weeks ago declared the water in Dimock safe to drink. It is also the clearest sign yet that regulators are concerned about the effect of drilling on drinking water there.
Dimock has become the center of a national debate over the natural gas extraction technique known as fracking, which involves pumping millions of gallons of chemical-laced water into shale rock deep below the ground.
Fracking has unlocked decades of natural gas supply, but environmentalists say it contaminates water supplies.
As fracking increases in the United States and contributes to an energy boom, the EPA is conducting a national study to determine its impacts.
A recent EPA draft report showed that harmful chemicals from fracking fluids were likely present in a Wyoming aquifer near the town of Pavillion.
Industry denies that fracking, which is being done across the country, poses a threat to drinking water.
(Additional reporting by Timothy Gardner in Washington, D.C.; Editing by Marguerita Choy and Lisa Shumaker)