Emission standards for hazardous air pollutants are set forth in the Section 112 of the Clean Air Act of 1970 and the National Ambient Air Quality Standard. Section 112 directed the Environmental Protection Agency (EPA) to issue a list of hazardous pollutants that were to be regulated. However, the provisions of the 1970 Clean Air Act that were designed to regulate hazardous pollutants proved to be ineffective. Although more than 300 toxic substances are known to be emitted into the air, between 1970 and 1990 emission standards were established for only eight substances: asbestos, benzene, beryllium, coke oven emissions, inorganic arsenic, mercury, radionuclides, and vinyl chloride. Although the EPA had epidemiologic and laboratory data that linked more than sixty other airborne toxins with cancer, birth defects, or neurological disease, they remained unregulated. The regulatory process specified by Section 112 was expensive and conservative. It...