Documents from Doll's Wellcome Foundation library archive reveal that he'd signed a contract with Monsanto -- then a chemical company but now a leader in GM crops -- in 1979 agreeing to a daily consultancy fee. When the contract was extended in the mid-1980s, Doll's consulting fee was $1,500 per day.
During the time the late Doll was acting as a consultant for Monsanto, he wrote to an Australian commission that was conducting an investigation to determine possible links between Monsanto-manufactured Agent Orange -- a toxic herbicide used during the Vietnam War to defoliate forests -- claiming there was no evidence that the chemical caused cancer.
The Guardian also revealed that the Chemical Manufacturers Association (CMA), Dow Chemicals and ICI -- a major chemical company -- paid Doll 15,000 pounds to review the possible cancer-causing properties of vinyl chloride, used to make plastics. Doll's review found the chemical was not linked to most cancers, except for liver cancer. The World Health Organization disagreed with Doll's findings, though the CMA used his review to defend its use of the chemical for more than a decade.
Doll's colleagues said he had always been open about his financial ties to the chemical industry, and that all his consulting fees were donated to the postgraduate institute he founded at Oxford, Green College.
"Richard Doll's lifelong service to public health has saved millions of lives," said Professor John Toy, medical director of Cancer Research UK. "His pioneering work demonstrated the link between smoking and lung cancer and paved the way towards current efforts to reduce tobacco's death toll. In the days he was publishing, it was not automatic for potential conflicts of interest to be declared in scientific papers."
However, Professor Lennart Hardell of University Hospital, Orebro in Sweden said he believes some of Doll's work caused the role of chemicals in cancer to be underestimated.
"It's okay for any scientist to be a consultant to anybody, but then this should be reported in the papers that you publish," he said.