An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

EPA's Study of Hydraulic Fracturing and Its Potential Impact on Drinking Water Resources

Retrospective Case Study in Killdeer, North Dakota

Case Study Background

EPA conducted a retrospective case study in Killdeer, North Dakota to investigate potential impacts to drinking water after a reported blowout of a well during the hydraulic fracturing. The findings help shed light on the vulnerabilities to drinking water resources from well blowouts during hydraulic fracturing and the potential ways to help prevent impacts to drinking water resources.

Key Findings

  • The domestic wells sampled did not show the presence of chemicals or brine associated with the blowout. However two monitoring wells screened in the Killdeer aquifer showed the presence of brine and tert-butyl alcohol (TBA). Based on the data analysis performed, the only potential source consistent with the TBA and brine at the two monitoring wells was the blowout during hydraulic fracturing that occurred in Killdeer, ND.  

State Activities at the Case Study Location

North Dakota responded to the blowout and the site remediation is complete. No further actions are required for this site.

Sampling Activities

EPA completed three rounds of water sampling from July 2011 to October 2012. Ground water samples from the Killdeer Aquifer were collected from domestic wells, monitoring wells, one state well, one municipal well, and water supply wells.

Data Reports

Map of Dunn County, North Dakota
Location of sampling sites in Dunn County, North Dakota. Click image to view larger image.