Extrapolation of the evidence on teratogenicity of chemicals between humans and experimental animals: chemicals other than drugs.

Epidemiologic literature regarding the possible association between malformations and 23 exposures or occupations other than pharmaceutical products, was analysed. The qualitative level of scientific evidence was classified into four categories: high (ethanol, methylmercury, PCBs, laboratory work), limited (anesthetic gases, carbon monoxide), low (hexachlorophene, LSD, nitrous oxide, smelter work, tobacco), and inadequate (all other exposures). Human data for exposures belonging to categories "high" and "limited" were quantitatively compared to results of animal teratogenicity tests of the relevant chemicals. Ethanol, methylmercury, and PCBs have caused malformations in experimental animals, and the effective doses have ranged from 0.2 to 8.0 times the effective human doses. Ethanol and PCBs caused similar types of lesions in some animal species as have been observed in humans.