"Tim Streater" wrote in message
...
In article ,
"harryagain" wrote:

One also gets the releaase of toxic gases and substance sto the surface
sometimes at least.

Which ones?
http://en.wikipedia.org/wiki/Frackin...nmental_impact

http://en.wikipedia.org/wiki/Environ..._contamination

http://en.wikipedia.org/wiki/Environ..._contamination