2/5. In the summer of 1988, the people of the small Cornish town of Camelford discovered their drinking water had gone sticky. It burned their lips, curdled their tea and turned their hair blue. The water authority told people not to worry, but took a fortnight to come clean and admit that the supply had been contaminated with 20 tons of aluminium sulphate that had been accidentally dumped in the wrong tank. Eighteen years on, evidence is still emerging of possible long-term poisoning. Liz Carney pieces together the story.