The EPA Draft Report of Groundwater Contamination Near Pavillion, Wyoming: Main Findings and Stakeholder Responses

Peter Folger
Specialist in Energy and Natural Resources Policy

Mary Tiemann
Specialist in Environmental Policy

David M. Bearden
Specialist in Environmental Policy

On December 8, 2011, the U.S. Environmental Protection Agency (EPA) issued a draft report on its investigation of groundwater contamination near the town of Pavillion, Wyoming. Under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), residents of Pavillion petitioned EPA, asking the agency to investigate whether groundwater contamination exists, its extent, and possible sources. Following the petition, EPA began its investigation three years ago. Although the final report may contain revised or more specific conclusions, the draft report indicated that EPA had identified certain constituents in groundwater above the production zone of the Pavillion natural gas wells that are consistent with some of the constituents used in natural gas well operations, including the process of hydraulic fracturing. In its report, EPA claimed that its approach to the investigation best supports the explanation that inorganic and organic compounds associated with hydraulic fracturing have contaminated the aquifer at or below the depths used for domestic water supply in the Pavillion area. EPA also stated that its approach indicates that gas production activities have likely enhanced the migration of natural gas in the aquifer and the migration of gas to domestic wells in the area. EPA did not appear to conclude that there was a definitive link to a release from the production wells, nor to the constituents found in domestic wells in shallower parts of the aquifer.

Because the draft report linked groundwater contamination in the deeper portions of the Wind River Formation aquifer to activities related to hydraulic fracturing during natural gas production in the area, it raised concerns about hydraulic fracturing practices in general. Organizations representing portions of the natural gas industry and other stakeholders took issue with some of the findings in the draft report, and questioned the scientific validity of EPA’s contention that “the explanation best fitting the data for the deep monitoring wells is that constituents associated with hydraulic fracturing have been released into the Wind River drinking water aquifer at depths above the current production zone.”


Date of Report: January 25, 2012
Number of Pages: 24
Order Number: R42327
Price: $29.95

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