A recent study by the Department of Energy’s National Energy Technology Laboratory (NETL) indicates that chemical-laced fluids used in hydraulic fracturing, or fracking, have not contaminated the drinking water at a test drill site in western Pennsylvania. Fracking, a technique used to extract natural gas trapped deep underground, has resulted in the boom in new gas wells being drilled in recent years, many in the Marcellus Shale formation that lies under parts of Pennsylvania, New York, Ohio and West Virginia. Opponents of fracking have claimed that the chemicals used in the drilling process could spread to drinking water supplies.

Throughout the year-long study, NETL researchers seismically monitored eight new horizontal wells in the Marcellus Shale formation situated underneath Pennsylvania, as well as several older wells located approximately 3,000 feet above the Marcellus Shale. NETL researchers also injected artificial “tracers” into drilling fluids, which were subsequently injected more than 8,000 feet below the surface, so they could monitor the fracking fluid injected into a natural gas well and see where it traveled. None of the tracers were subsequently detected in the monitoring zone 3,000 feet higher. The NETL report concluded that potentially toxic chemicals were at l east a mile removed from potential drinking water supplies, which typically are no more than 500 feet underground.