Dr. Gonzo
Stuck in my cabana, livin on bananas and blow.
I believe the point is that there were plenty of opportunities up until as recent as 2005 to regulate hydraulic fracturing within the scope of the safe drinking water act. For instance they could have added that hydraulic fracturing constitutes a serious impairment to safe drinking water and thus would be regulated under the following terms X,Y, and Z. As to the question of why it wasnt specifically regulated well thats a different argument entirely.
Mac, just so you know, the Energy Policy Act of 2005 specifically exempts fracking from the SDWA. Normally the SDWA regulates any "underground injection" in order to protect against contamination of underground drinking water sources such as aquifers.
The Energy Policy Act amends the definitions section of the SDWA so that the term "underground injection" does not include anything related to oil and gas exploration. So the issue is not that Congress decided not to bring the process under the Act's regulations but rather that Congress opted to take it out from under the regulatory scheme.