Regulation of occupational carcinogens under OSHA's Air Contaminants Standard

We compare the information used by the Occupational Safety and Health Administration (OSHA) to regulate carcinogens under its 1989 Air Contaminants Standard to publicly available information on substances with potential carcinogenic activity. Carcinogenicity evaluations were obtained from the National Institute for Occupational Safety and Health (NIOSH), the American Conference of Governmental Industrial Hygienists (ACGIH), the National Toxicology Program (NTP), the Environmental Protection Agency (EPA), and the International Agency for Research on Cancer (IARC). We focus on three sets of substances: those which were regulated as carcinogens by OSHA in the Standard, those which were included in the Standard but whose exposure limits are based on noncarcinogenic effects, and those substances designated as potential carcinogens by NIOSH, ACGIH, and/or NTP but which were excluded from the Standard. The data indicate that OSHA relied almost exclusively upon the recommendations of the nongovernmental ACGIH to the exclusion of IARC and the three governmental bodies. Given their statutory authority to evaluate chemical carcinogenicity for regulatory agencies such as OSHA, the exclusion of NIOSH and NTP is particularly striking.