Are all hazardous waste sites equally threatening to the public’s health? How does one differentiate between sites on the basis of human health hazard? This chapter describes the public health assessment of uncontrolled hazardous waste sites. It details the steps in a public health assessment and presents salient findings from assessments of CERCLA sites. The 30 hazardous substances found most often in completed exposure pathways are identified, and the national level of public health hazard of NPL sites is described.