The Environmental Protection Agency released a report which it says is based on science. It examines the relationship between hydraulic fracturing and drinking water. The report Hydraulic Fracturing Drinking Water Assessment says yes, fracking does pose a threat to drinking water.
The EPA identified 1600 chemicals which are used in the fracking process. It concludes that 11% of these chemicals pose a threat to human health. And while chemicals used in fracking have been closely guarded industry secrets, the EPA says next month they will publish a data base listing these chemicals. However when we asked they did not provide insight into the relationship between clusters of health problems in areas with large numbers of fracked wells.
While the EPA says their report is based on science, it may have bowed to political pressure. Back in 2015 they issued a preliminary report. It said fracking poses "widespread systemic impacts." Now the report concludes that fracking can impact drinking water resources "under some circumstances." You can read the EPA’s report here.
Meanwhile Donald Trump is trying to line the EPA with fracking enthusiasts and climate deniers.