Adoption of fracking by commercial energy companies has resulted in larger national energy independence gains than the billions invested by the government in alternative energy. But capitalism doesn't necessarily make the best choices. It is sort of like allowing primary school children plan the school menu.
There is are a couple of unknown environmental risks with fracking. As I have blogged before, we don't know the impact on generating earthquakes. The biggest unknown is the impact on the aquifers we use for drinking water. Once they are contaminated, they are contaminated for eternity.
Fracking 'could put gas and chemicals' in drinking water explains UK water suppliers are warning fracking could pose a treat if not "carefully planned and carried out." The devil is in the details. What does 'carefully planned and carried out' really mean?
Even if geologically the aquifer is perfectly sealed, penetrating the aquifer with a well exposes the aquifer if the well casing were to leak or crack. If the aquifer is not geologically sealed, methane could penetrate porous rock and enter the aquifer. Waste water handling on the surface could permeate to the aquifer - a typical well uses a million gallons of chemicals and water to force the shale oil or gas into horizontal collection channels.
Mmm. Stuff happens - I think it is a safe bet an aquifer will be contaminated.