The letters ask for “cooperation in a scientific study,” yet make it clear that legal action will be taken if this is not given.
“EPA is requesting that you provide this information voluntarily; however, to the extent that EPA does not receive sufficient data in response to this letter, EPA will be exploring legal alternatives to compel submission of the needed information.”
The natural gas extraction process was exempted from oversight under the Safe Drinking Water Act in 2004 on the basis of an earlier report. Public concerns have grown since then, and the exemption is being re-examined.