EPA Links Fracking in Wyoming to Groundwater Contamination

On December 8, the EPA issued a draft report which indicated that gas production activities, including hydraulic fracturing, are the likely causes of groundwater contamination identified in Pavillion, Wyoming. The report was lauded by environmentalists who believe it provides evidence that fracking causes groundwater contamination, a contention they have long held. The Pavillion investigation was conducted under the authority of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and is separate from the broader study EPA is conducting on the potential impacts of hydraulic fracturing on drinking water. However, the results will undoubtedly be incorporated into that study.

EPA conducted groundwater sampling in Pavillion over a two-year period from 2009 to 2011, sampling domestic and municipal wells, as well as shallow and deep monitoring wells in four sampling events. The data revealed concentrations of benzene and methane, as well as synthetic chemicals associated with hydraulic fracturing fluids such as glycols and alcohols.  EPA concluded that the potential source of shallow groundwater contamination was the pits used for disposal of drilling cuttings, flowback, and produced water. EPA acknowledged the increased complexity of identifying the source of contaminants detected in deep groundwater, but concluded the best explanation for the data was that “constituents associated with hydraulic fracturing have been released into the Wind River drinking water aquifer at depths above the current production zone.”

On December 12, Encana Oil and Gas (USA) Inc., the owner of the gas field, issued a strong statement refuting the study. Encana claimed the high methane and benzene levels are naturally occurring because the deep monitoring wells are located in a natural gas reservoir.  Encana also criticized the EPA’s study methodology because many of the synthetic chemicals detected in the deep wells were found in quality control samples and had never been detected in other wells. Encana also pointed out that EPA’s sampling of the domestic water wells did not reveal oil and gas contaminants above federal or state drinking water standards.

EPA will accept public comments on the study for 45 days beginning December 14, 2011.  Following the public comment period, the report will be peer-reviewed by a panel of independent scientists.