Nicholas Ashford, Professor of Technology and Policy at Massachusetts Institute of Technology, says he thinks chemicals are the most serious environmental problem facing industrialised countries today. The theory suggests people can become sensitised by exposure to one form of contamination so that they are then liable to be affected by a whole range of other pollutants, including detergents, traffic fumes and tobacco smoke. It may sound a far-fetched theory. But the experience of many British sheep farmers gives it credence. The symptoms range from the fairly mild sneezing and runny eyes of 'dipping 'flu' to muscle spasms, insomnia and overpowering fatigue.
Some farmers say they have been driven to the brink of suicide.
OPs are highly toxic, derived from the same group of chemicals that the Nazis used in World War Two to manufacture nerve gases. Crucially, many farmers report that after exposure to OPs, they find that their symptoms can then be triggered off by exposure to a range of other chemicals. Patients become sensitised OPs are not used exclusively in sheep dips. They are also used for fumigating public transport vehicles, in shampoos, and in flea collars. So they are widely available.