This chapter defines and describes hazardous wastes and their adverse health effects. Historical evolution of the management and public understanding of waste issues is traced. Other parts of the chapter describe hazardous waste management, including disposal landfills, land farming, incineration, and toxics use reduction. Various regulatory measures are described as well as nonregulatory measures for prevention and control of adverse health effects from hazardous wastes. Approaches to evaluating human health effects at hazardous waste sites are described, emphasizing special challenges and opportunities in environmental epidemiology. Social aspects of community involvement are noted. Steps of the Superfund clean-up process are delineated. Governmental contingency plans for coordination in emergency response situations are reviewed. In addition, a section describes pollution prevention and toxics use reduction.