I was reminded of the chapter in Bill Bryson's book, A Short History of Nearly Everything, http://www.randomhouse.com/features/billbryson/bb_title/display.pperl?is...
regarding the continual denial of the lead poison by detroit. They had a press conference in 1940's or 1950's where a prominant lead executive put his hands in a vat of lead in front of cameras and said it was entirely safe. I think there was support from the car industry for the addition of lead to petrol as it saved money and kept the engines from knocking. I think the denial of medical evidence of lead poisoning led to the inclusion in all sorts of materials besides petrol, like paint in children's toys.