PITTSBURGH – A landmark federal study on hydraulic fracturing, or fracking, shows no evidence that chemicals from the natural gas drilling process moved up to contaminate drinking water aquifers at a western Pennsylvania drilling site, the Department of Energy told the Associated Press.
After a year of monitoring, the researchers found that the chemical-laced fluids used to free gas trapped deep below the surface stayed thousands of feet below the shallower areas that supply drinking water, geologist Richard Hammack said.
The ongoing study is the first independent look at whether the potentially toxic chemicals pose a threat to people during normal drilling operations. But DOE researchers view the study as just one part of ongoing efforts to examine the impacts of a recent boom in oil and gas exploration, not a final word about the risks.
Drilling fluids tagged with unique markers were injected more than 8,000 feet below the surface at the gas well bore but weren’t detected in a monitoring zone at a depth of 5,000 feet. The researchers also tracked the maximum extent of the man-made fractures, and all were at least at depths of 6,000 feet.
That means the potentially dangerous substances stayed about a mile away from surface drinking water supplies, which are usually at depths of less than 500 feet.
Many of the tens of thousands of new gas wells are in the Marcellus Shale formation that lies under parts of Pennsylvania, New York, Ohio and West Virginia.
The study was done by the National Energy Technology Laboratory in Pittsburgh.