The most dangerous aspect of
hydraulic fracking is the possibility to induce
earthquakes - directly, as fracking is intended to crack up underground hard shales, and indirectly, because through these cracks, water can enter into surrounding layers of
anhydrite, and cause the material to swell. The risk is systematic, as anhydrite is a typical component of
salt domes, which are the formations where you typically find oil and gas deposits (
shallow seas->organic material sinks down->evaporation covers the material with layers of salt->pressure converts the organic material into oil/gas->salt-dome cover prevents oil diffusion->exploitable oil/gas concentration).
It's pretty difficult and/or expensive, however, to prove a direct relation between fracking and earthquakes, which means, should your house be damaged by an earthquake, you might run into problems claiming compensation from the nearby fracking operator.
Alternatively to hydraulic fracking, pressurised COČ may be used (to my knowledge, it is already being used on some oilfields in Western Texas). Pressurised COČ leaves the risk of directly-induced seismic activity, but eliminates the indirect risk of water-induced swelling of covering layers. The COČ increases oil viscosity, thereby reducing or even eliminating the need for additional solvents that may potentially contaminate underground water. Furthermore, most of the COČ remains underground, so the technology is (at least temporarily) reducing atmospheric COČ concentration.
For the a/m reasons, I am against hydraulic fracking, while COČ fracking should be researched further, eventually even be encouraged.
