"Top officials of the U.S. Environmental Protection Agency last year made critical changes at the eleventh hour to a highly anticipated, five-year scientific study of hydraulic fracturing’s effect on the nation’s drinking water. The changes, later criticized by scientists for lacking evidence, played down the risk of pollution that can result from the well-drilling technique known as fracking.

Documents obtained by APM Reports and Marketplace show that in the six weeks before the study’s public release, officials inserted a key phrase into the executive summary that said researchers did not find evidence of “widespread systemic impacts” of fracking by the oil and gas industry on the nation’s drinking water.

Earlier draft versions emphasized more directly that fracking has contaminated drinking water in some places."

Scott Tong and Tom Scheck report for Marketplace and APM Reports November 30, 2016. [2]