What evidence do you have for this?
I started reading this -
http://ec.europa.eu/environment/integration/energy/pdf/fracking study.pdf
- the other day.
In summary...
General risk causes
In general, the main causes of risks and impacts from high-volume hydraulic fracturing
identified in the course of this study are as follows:
The use of more significant volumes of water and chemicals compared to
conventional gas extraction
The lower yield of unconventional gas wells compared to conventional gas wells
means that the impacts of HVHF processes can be greater than the impacts of
conventional gas exploration and production processes per unit of gas extracted.
The challenge of ensuring the integrity of wells and other equipment throughout the
development, operational and post-abandonment lifetime of the plant (well pad) so as
to avoid the risk of surface and/or groundwater contamination
The challenge of ensuring that spillages of chemicals and waste waters with potential
environmental consequences are avoided during the development and operational
lifetime of the plant (well pad)
The challenge of ensuring a correct identification and selection of geological sites,
based on a risk assessment of specific geological features and of potential
uncertainties associated with the long-term presence of hydraulic fracturing fluid in
the underground
The potential toxicity of chemical additives and the challenge to develop greener
alternatives
The unavoidable requirement for transportation of equipment, materials and wastes to
and from the site, resulting in traffic impacts that can be mitigated but not entirely
avoided.
The potential for development over a wider area than is typical of conventional gas
fields
The unavoidable requirement for use of plant and equipment during well construction
and hydraulic fracturing, leading to emissions to air and noise impacts.
I am unsure as to its impartiality, i have been meaning to get some background on the author but have had a bout of the CBA's.