A report issued in May from the US-based Natural Resources Defence Council investigated fracking water disposal processes in Pennsylvania.
It found that the five main ways of dealing with fracking wastewater posed a significant risk to human health.
It said "significant concern has been raised" regarding the nature of some fracking activities, with 29 identified as of particular concern for human health and 13 identified as probable or known human carcinogens.
Among the most notable are 2-butoxyethanol, naphthalene, benzene, and polyacrylamide.
Contaminated wastewater has long been one of the biggest concerns about fracking, and this report confirms that current practices put both the environment and public health at risk.
Further studies from the University of Texas and Cornell have found a direct link between fracking and significant environmental contamination.
Opening Britain up to fracking would require the construction of a whole new set of pipelines to transport shale gas.
These pipelines bring up a whole new set of problems when they blow up, as demonstrated by the Deepwater Horizon disaster a couple of years ago.
Shale gas quite simply cannot be extracted without significant environmental impact. To allow it to go ahead would be a polluter's charter.