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"Bisphenol A: A Scientific Evaluation" Concludes That Risk of Bisphenol A to Humans is Very Low

October 4, 2004

A recent paper (1) by Professor Michael A. Kamrin (2)reports the conclusions of his scientific evaluation of the safety of bisphenol A (BPA) in a concise form that is very readable. In his overall conclusion, Professor Kamrin states:

"[I]t is very unlikely that humans, including infants and young children, are at risk from the presence of BPA in consumer products."

To reach his conclusions, Professor Kamrin systematically evaluated the extensive scientific research on BPA from several perspectives, each of which is summarized in his paper:

• What is it and how is it used?
  
• How are children and adults exposed to BPA?
  
• What is the magnitude of BPA exposure?
  
• What is the toxicity of BPA?
  
• What kinds of toxic effects does BPA cause?
  
• What are the risks of BPA in humans?

As reported by Professor Kamrin, BPA is primarily used as a raw material to make polycarbonate plastic and epoxy resins, both of which are used in a variety of consumer products, including some that come into contact with food. Realistic human exposure to BPA, primarily through food, has been estimated to be in the range of about 0.001 to 0.1 micrograms/kilogram body weight/day. The available data suggest that exposures per body weight for adults and young children are similar.

Based on extensive toxicity test data, acceptable exposure levels in the range of 10-50 micrograms/kilogram body weight/day have been established by government agencies worldwide. These acceptable levels are set to be at least 1000 times below the lowest levels at which effects are seen in toxicity tests on laboratory animals, partly under the assumption that humans may be more sensitive than laboratory animals to toxic effects from BPA exposure.

A comparison of the high end of the realistic exposure range with these acceptable exposure levels results in an estimated margin of safety of 100-500. As pointed out by Professor Kamrin, the actual margin of safety is likely to be even higher since metabolism studies have shown that humans are likely to be less sensitive to toxic effects from BPA exposure than laboratory animals, contrary to the assumption used to set the acceptable exposure levels.

Based on his scientific evaluation, Professor Kamrin's paper concludes with the following overall assessment:

"Thus, the evidence that has been collected in recent years coupled with experience from decades of occupational exposures indicates that the risk of BPA to humans of all ages is very low. It is thus very unlikely that humans, including infants, will suffer any adverse consequences, including endocrine-related effects, from current exposures to BPA in food, drink, or other consumer products."

1. "Bisphenol A: A Scientific Evaluation." Medscape General Medicine, 6(3), 2004. Available on the Internet at http://www.medscape.com/mgmhome in the Special Articles section. Free registration is required to access the article.

2. Michael A. Kamrin, PhD, Professor Emeritus, Institute for Environmental Toxicology, Michigan State University, East Lansing, Michigan.