The National Institute for Occupational Safety and Health (NIOSH) received a request for a health hazard evaluation (HHE) at U.S. Magnesium in Rowley, Utah from the management, United Steel Workers of America, and the Environmental Protection Agency (EPA). The requestors wanted to find out the extent of exposure to carbon tetrachloride, chlorine, and chlorinated hydrocarbons, including debenzo-p-dioxins, chlorinated dibenzofurans, polychlorinated biphenyls, and hexachlorobenzene during the processing of magnesium.