The Cleanup of Severely Contaminated Groundwater Sites May … EP Magazine The Cleanup of Severely Contaminated Groundwater Sites May Have to Wait. According to a report from the National Research Council, there are at least … The Cleanup of Severely Contaminated Groundwater Sites May Have to Wait According to a report from the National Research Council, there are at least 126,000 contaminated groundwater sites across the U.S. that requires remediation. Of these, 10 perfect are considered “complex”, which means that restoration is unlikely to happen in the next 50 to 100 years because of technical limitations. Nov 09, 2012 Several national and state groundwater cleanup programs developed over the last three decades under various federal and state agencies aim to mitigate the human health and ecological risks posed by underground contamination. These programs include cleanup at Superfund sites, facilities that treat, store, and dispose of hazardous wastes, leaking underground storage tanks, and federal facilities. The U.S. Department of Defense has already spent approximately $30 billion in hazardous waste remediation to address past legacies of its industrial operations. DOD sites represent approximately 3.4 percent of the total active remediation sites, but many of these sites present the greatest technical challenges to restoration with very high costs. Therefore, the agency asked the National Research Council to examine the future of groundwater remediation efforts and the challenges facing the U.S. Army and other responsible agencies as they pursue site closures. The estimated range of remediation costs do not account for technical barriers to complete cleanup at complex sites or the costs of cleanup at future sites where groundwater may become contaminated. A substantial portion of the costs will come from public sources as some of complex sites are "orphan" sites and many other complex sites are the responsibility of federal or state agencies .