Risk Assessment for Carcinogens: A Comparison of Approaches of the ACGIH and the EPA

Abstract The relative carcinogenic potency of 16 chemicals evaluated by both the U.S. Environmental Protection Agency (EPA) and the Chemical Substances Threshold Limit Values (CS-TLV) Committee of the American Conference of Governmental Industrial Hygienists (ACGIH) were compared. The estimated cancer risk resulting from occupational exposure to the threshold limit values (TLVs) were also computed using dose-response curves developed as a part of EPA quantitative risk assessments. Substantial agreement between the EPA and the CS-TLV Committee was found when the relative potency of these carcinogens was compared. Use of EPA's risk model to estimate lifetime cancer risk from occupational exposure at the TLV levels often resulted in high cancer risk estimates. The approaches used to assess cancer risk by both groups is described and a suggestion is made for incorporating existing quantitative risk assessments into the TLV evaluation procedure.