Oil drilling has used explosives to break up subsoil rock for more than a century , this has caused polluting accidents now and then for this same period.
Hydraulic fracturing is the latest thing , but is just a development on older technology, done right it is not especially dangerous and can be less polluting than drilling new wells.
Earthquake danger ought to be studied as an important possibility , there might be some places that are prone to earthquake or possibly triggered by fracking , but this has happened with water drilling too,