The head of the Health Canada scientific team studying the safety of bisphenol A has been abruptly reassigned, while the department investigates claims he is too biased in favour of the chemical to objectively analyze it.
Speaking at a medical conference in the U.S. in March, Mark Richardson, manager of Health Canada's contaminated-sites division, endorsed the use of bisphenol A after he had been selected to undertake a review of the health impacts of the chemical.
He indicated at the conference that he personally didn't think bisphenol A presented a danger, extolled the virtues of its use in dentistry and dismissed possible health threats posed by exposures to the substance, comparing it to eating tofu.
The Globe and Mail raised questions about Dr. Richardson's objectivity yesterday morning with Health Canada. Shortly afterward, Health Minister Tony Clement's office asked for an investigation into Dr. Richardson's remarks and suitability to work on the review. The investigation will be conducted by the department's chief scientist, Wendy Sexsmith.
"We are aware of the concern that has been communicated to the department," Paul Glover, director-general of the department's consumer safety branch, said in explaining the action.
Bisphenol A is one of the most controversial chemicals in widespread use because it has been found to mimic the female hormone estrogen. Almost all Canadians have involuntary exposure to it because it is used in such items as hard plastic baby bottles, resins lining food cans and dental composite materials used in white-coloured fillings.
Traces of bisphenol A leach from consumer products into people. There is a growing body of scientific research using animal experiments that link exposures to health problems, such as abnormal breast tissue growth and enlarged prostates.
At the conference, Dr. Richardson dismissed these concerns, saying "yes, bisphenol A is estrogenic, it interacts with estrogen receptors, but a myriad of other things do as well, including proteins in tofu," which he said is recommended by some as a treatment for menopause. He also said bisphenol A exposures are "so low as to be totally inconsequential, in my view."
However, there have been more than a dozen studies in laboratory animals since 1999 finding adverse effects from bisphenol A at levels below Canada's current standard. One study, done in 2005, found the chemical able to change breast tissue in ways that predispose it to cancer - at a dose 1,000 times lower than Canada's limit.
Tofu, and many products from plants, contain estrogen-like chemicals and there is scientific uncertainty about their possible health effects.
The federal government is reviewing the safety of 200 potentially dangerous synthetic chemicals - including bisphenol A - that were used in the 1980s but were grandfathered from detailed safety assessments when Canada adopted its first comprehensive pollution legislation.
Bisphenol A is one of the largest volume chemicals made in the world, and any decision by Ottawa to restrict it would have major economic impacts if other countries follow. Last month, four major bisphenol A manufacturers, Dow Chemical Co., GE Plastics, Bayer MaterialScience, and Sunoco Chemicals, hired Tactix Government Consulting, a well-placed Ottawa-based lobbying firm, to help them respond to the review.
The industry disputes assertions that bisphenol A is dangerous.
Dr. Richardson is an expert on the dangers of amalgam fillings, or those containing mercury. He was a guest speaker at the conference, held in Tucson and organized by the International Academy of Oral Medicine and Toxicology, a Florida-based medical group concerned about dental material safety.
In his talk, Dr. Richardson conveyed the thinking within Health Canada on the grandfathered chemicals, saying they weren't acutely toxic because "we've been using them for a few decades and we don't seem to have a trail of dead bodies around."
However, he added that the chemicals weren't studied in depth. "I hate to say it but we're a big pool of guinea pigs with a lot of these things."
Dr. Richardson said he is convinced that dental composites using bisphenol A are safer than amalgam. He personally felt so strongly about this that he had his 15 amalgam fillings replaced with composites.
