In response to the threat to human health and the environment posed by numerous uncontrolled hazardous waste sites across the country, new remedial action technologies are evolving and known technologies are being retrofitted and adapted for use in cleaning up these sites. The report identifies and assesses various types of site response activities which have been implemented, are in progress, or have been proposed to date at Superfund-financed and enforcement action hazardous waste sites in the United States. A nationwide survey was conducted in which 30 uncontrolled hazardous waste sites were identified where either some form of enforcement action was planned or where remedial actions were Superfund-financed. Based on an assessment of the 30 sites, eight sites were selected for which detailed case study investigations have been conducted. The document presents case study reports for each of the eight sites. These reports include extensive discussions of the remedial responses at each of the eight sites with respect to technology, cost, and institutional framework.