Managing air toxics under the new Clean Air Act Amendments

The U.S. Environmental Protection Agency (EPA) has been regulating air toxics (hazardous air pollutants) under Section 112 of the 1970 Clean Air Act Amendments. To date, EPA has established emission standards for seven hazardous air pollutants. They include arsenic, asbestos, benzene, beryllium, mercury, vinyl chloride and radionuclides. EPA had determined that the low risks associated with electric utility fossil fuel power plant radionuclide emissions did not justify regulation under Section 112. The Clean Air Act Amendments of 1990 greatly expand EPA's rulemaking authority over toxic or hazardous air pollutants. The law lists 189 chemicals that would be subject to control. Sources that emit 10 tons/yr or more of any one pollutant, or 25 tons/yr or more of any combination thereof, must apply maximum available control technology (MACT). By definition, MACT is at least as stringent as best available control technology (BACT) for similar sources. However, consideration of the cost and feasibility of control, energy impacts and environmental factors will be given in MACT. Under the new amendments, the EPA will conduct a three-year study of the public health hazards from exposure to toxic emissions from utilities and report to Congress. EPA can regulate such emissions only if the regulations aremore » appropriate based on this study. Two additional studies addressing mercury are also required. The first directs the EPA to conduct a four-year study of mercury emissions from electric utility steam generating units, municipal waste combustion units, and other sources. Included in this paper are evaluations of the rate and mass of such emissions, of health and environmental effects, and of the available control technologies and their costs.« less