SIR — Some very strange and unscientific facts are being pronounced by those who opposed the recovery of our valuable reserves of shale gas by the fracking process. They relate to the possible contamination of our water supplies from our natural acquifers within the upper crust. No commercial water company supplying our towns and cities would risk delivering water to our taps without highly stringent processes of purification rendering waters clean, tasteless and odourless. Equally, no company engaged in shale gas recovery would employ dangerous chemicals in the process at the risk of their prosecution. We know from American experience that the principal reason would be methane, which is water soluble and quickly dispersed through ground waters without long-term effect. Much greater risks arise daily from careless release of oil residues from garages and infinitely more from the slurry pits of farms in our countryside. It is to our advantage that water companies also deal with our sewage waste and, indeed, process it along with river waters to produce a large percentage of our portable drinking water. Years ago, a lapse of American carelessness caused the accident at the atomic plant at Five Mile Island. The nuclear industry is never allowed to forget this and the warning is trotted out at all occasions. For fracking, methane flaring from taps, again in America, has acquired a similar notoriety. Subsequent experience has dealt with that risk, be assured. Sometimes I despair of the understanding of science by my generation, but I have greater hopes for our young people thanks to modern schooling and the briefing in current awareness. Eric Robinson, Whitehall, Watchet.