Carcinogenesis in Rats of Combined Ethylene Dibromide and Disulfiram

Abstract

To the Editor.— A study of the toxicity of inhaled ethylene dibromide (EDB; 1,2-dibromoethane), a widely used industrial chemical, is currently being performed for the National Institute for Occupational Safety and Health by the Midwest Research Institute (MRI), Kansas City, Mo. Male and female Sprague-Dawley rats are being exposed to EDB at the current US Occupational Standard of 20 ppm or to filtered air (controls) for seven hours a day, five days a week. There are four groups of animals in the study, each group containing 48 male and 48 female rats. The group designations are as follows: (1) control/control—filtered air exposed, standard rat diet; (2) control/disulfiram—filtered air exposed, diet containing 0.05% disulfiram by weight; (3) EDB/control—20 ppm EDB, standard rat diet; and (4) EDB/disulfiram—20 ppm EDB, diet containing 0.05% disulfiram by weight. Disulfiram was chosen as a potential modifier of toxicity because of its known effect as an enzyme