Evaluates the technical soundness of existing methods for assessing the risks posed by unexploded ordnance at U.S. military installations. This report examines methods for assessing the risks of unexploded ordnance (UXO) on former military training land, particularly sites on closed or transferred bases that will be or have been converted to civilian use. This work is the first to analyze in detail all the approaches the Army has developed to assess the risks of UXO sites, recommending ways for the Army to develop risk assessment protocols acceptable to all parties with an interest in UXO sites.