The regulation of hazards is one of the most dramatic.forins of intervention in occupational safety and heulth (OSH). Despite their high degree of potential social arid econotnic impact, relatively little research has been conducted to specifically evalutrte the eflectiwness of OSH standards with regard to preventing occupational diseases arid injuries. This paper reviews the basic scient(fic approaches that may be used to evaluate the efSicacy of OSH standards. These approaches encompass the following research areas: ( I ) exposure surveillance, (2) disease surveillance, and ( 3 ) prospective studies ,fi)llowing the introduction of the stundard. Research on asbestos and asbestosis, respirable crystalline silica (quartz) and silicosis, and respirable cool mine dust and coal workers' pneutnoconiosis (C WP) are used to illustrate these approaches and the type of it formation that ic currently available. The e-rumples (quartz, coal dust, asbestos) reveal substantial limitations in the types of information currently available for rvaluuting the efsicucy of these OSH standards. Ideally, plans .for evaluating the eflicacy of OSH standards should be developed,for existirig and.future standards. These plans should include programs for the surveillance of exposures and adverse health effects and, when possible, for prospective studies designed to evaluate how the risk of disease (or injury) is modifed by the introduction of the standurd. 0 I996 WiIr>-Liss. 1nc.