The groups, including the Sierra Club, the Natural Resources Defence Council, and Food and Water Watch,echoed concerns previously voiced by the agency's Science Advisory Board (SAB) about the report's conclusion, which did not find any evidence that fracking had led to "widespread, systemic" contamination of drinking water.
The EPA did not clearly define what it meant by "widespread" and "systemic" impacts, the groups argued in a letter sent Monday to the agency.
