"A gas extraction method which triggered two earth tremors near Blackpool last year should not cause earthquakes or contaminate water but rules governing it will need tightening, experts say".
They surely will.
"Each well is lined with layers of steel and cement; and if this stays intact, the scientists conclude, gas leakage should not be a problem."
Thats the interesting bit. This is not gauranteed. Notice its says "if".
http://www.bbc.co.uk/news/science-environment-18611647
