Chris Hogg wrote:

I can see armies of the ignorant believing
that fracking uses carcinogenic material and we're all going to die of
cancer if fracking is allowed.

The armies of the ignorant probably don't realise fracking has been used
in hundreds of UK onshore oil/gas sites for decades.

http://www.bbc.co.uk/news/uk-england-23756320
https://en.wikipedia.org/wiki/East_Midlands_Oil_Province#Geography

The difference is that for shale you need higher pressures and volumes
than limestones and sandstones.