since for forty years every study of lead's effects had been funded exclusively by manufacturers of lead additives. In one such study, a doctor who had no specialized training in chemical pathology17 undertook a five-year programme in which volunteers were asked to breathe in or swallow lead in elevated quantities. Then their urine and faeces were tested. Unfortunately, as the doctor appears not to have known, lead is not excreted as a waste product. Rather, it accumulates in the bones and blood - that's what makes it so dangerous - and neither bone nor blood was tested. In consequence, lead was given a clean bill of health.