A draft assessment compiled by the US Environmental Protection Agency (EPA) on the potential threat to drinking water supplies presented by shale gas exploration has found “no evidence of any widespread, systemic impacts.”
Additionally, EPA said, its studies of fracking under very different conditions in the states of Florida and Colorado have shown that the practice does not generally lead to a water imbalance.
The agency called its research, conducted at the behest of the US Congress, “the most complete compilation of scientific data to date,” although opponents of fracking pointed out that not all of the 950 internal and external documents it surveyed examined the effects of the process on drinking water directly.
Components of the process looked at included chemical mixing at the well pad site, well injection of fracking fluids and collection of wastewater, including flowback and the “produced” water that moves back with the wellhead with the gas.
In a nutshell, EPA said that while it believed fracking is being carried out responsibly in most cases, there are vulnerabilities that should be considered. It saw challenges in water withdrawal in areas of low availability, fracking directly into shale formations containing drinking water resources, inadequately cased or cemented wells resulting in below-ground migration of gases and liquids and the discharge of inadequately treated wastewater.
In any case, the environmental authority said, factors such as water user demands, water management practices and geologic conditions must be thoroughly understood to assess potential local impacts of fracking locally.
EPA’s final conclusion will have no consequences for US shale gas exploitation as state authorities, rather than the federal government, largely control the regulatory process.
The agency’s hands have been tied by legislative moves, such as removing its authority from the Clean Water Act and the Safe Drinking Water acts. Moves are also afoot on the part of US political conservatives and the fracking industry to keep the federal government out of regulation altogether.