For a variety of reasons, I follow the gas drilling in Pennsylvania pretty closely.  From what I hear, the gas companies vary as far as how careful they are in terms of protecting the environment.  I have specifically  heard that Range Resources is one of the better ones, that they run a very professional operation.   I believe that fracking is probably pretty safe when done in a professional manner and the wastewater is handled proplerly.  But there will always be those who are tempted to cut corners to make a few extra bucks, and so there will inevitably be more spills and so forth than there should be.