A new U.S. Environmental Protection Agency draft assessment confirms what many engineering, construction and oil and gas companies have been saying for years: that hydraulic fracturing, when done properly, does not have a negative impact on drinking-water sources.

The long-awaited, congressionally mandated study, released on June 4, examined the potential impacts that hydraulic fracturing and related activities can have on current drinking-water sources and potential sources, such as groundwater.

The assessment, which EPA says is more a scientific document than a policy report, concludes that U.S. hydraulic fracturing activities have not had “widespread, systemic impacts on drinking-water sources.”

Still, the assessment notes that potential vulnerabilities exist. They include: water withdrawals in arid or dry regions; fracking directly into formations containing drinking-water sources; inadequately cased or cemented wells resulting in below-ground migration of gases and liquids; inadequately treated wastewater discharged into drinking-water sources; and spills of fracking fluids or wastewater.

Supporters of oil and gas development cheered the EPA study’s findings. Senate Energy and Natural Resources Committee Chair Lisa Murkowski (R-Alaska) said in a statement: “States have been effectively regulating hydraulic fracturing for more than 40 years, and this study is evidence of that.”

Environmental groups criticized the report. Madeleine Foote, League of Conservation Voters legislative representative, said in a statement, “EPA’s draft assessment identified a number of threats the entire fracking process poses to drinking-water sources, and these vulnerabilities require further analysis and future regulation.”

Foote added that industry officials are “cherry-picking from this report to defend their specious claims that fracking is safe. This study actually underscores that we should move away from dirty fossil fuels because of the risks they pose to our valuable natural resources, like clean water and air."

Thomas Burke, EPA science advisor and deputy assistant administrator of its office of research and development, told reporters on June 4 that the document drew on more than 950 information souces, including published papers, technical reports, information from stakeholders and peer-reviewed EPA scientific reports, as well as EPA's original research.

EPA’s data review found specific instances where well integrity amd improper fracking-related wastewater management harmed drinking-water resources, but they were a relatively infrequent, given the large numbers of fractured wells across the country, Burke said.

The study document is a draft and will go through a public comment and peer-review process with EPA’s Science Advisory Board before it becomes final.

Burke said, “Once final, this assessment will provide the states, tribes, communities and industry across the country with a critical resource that they can use to identify how they can better protect public health and our drinking water resources.”