Preliminary results of a comprehensive Department of Energy (DOE) study of hydraulic fracturing found no evidence that chemicals from natural gas drilling operations contaminated drinking water. DOE’s National Energy Technology Laboratory (NETL) in Pittsburgh, Pennsylvania launched a year-long study of Marcellus Shale test sites in Washington and Greene Counties in southwestern Pennsylvania. In an April 2013 update, NETL said the study “will provide an unbiased, science-based source of information which can guide decisions about shale gas development.” The study found that chemicals utilized in hydraulic fracturing at the test sites remained thousands of feet below the shallower aquifers containing drinking water. Utilizing seismic testing and “man-made tracers” injected into the hydraulic fracturing fluids in the Marcellus shale gas wells over 8,000 feet in depth, NETL monitored older, shallower, sandstone wells at 4,000 feet – at least 3,000 feet below drinking water aquifers – to confirm that there was no “communication” between the Marcellus Shale and the sandstone units above. The monitoring project offered the federal government first-of-its-kind access to a company’s drilling operations and, according to NETL, “multiple lines of evidence” in testing for water contamination.  NETL geologist Richard Hammack reportedly characterized the large amount of field data that the studies have yielded to date as “the real deal” and likely to be analyzed “for years to come.”