Under the Defense Environmental Restoration Program (DERP), the Department of Defense (DOD) has charged the Army Corps of Engineers (the Corps) with cleaning up 4,700 formerly used defense sites (FUDS) and active sites that were under its jurisdiction when they were initially contaminated. The 661-acre Spring Valley site in Washington, D.C is one such site. Like many other FUDS, the U.S. Army used the Spring Valley site during World War I for research and testing of chemical agents, equipment, and munitions. Most of the site is now privately owned and includes private residences, a hospital, and several commercial properties. The primary threats at the site are buried munitions, elevated arsenic in site soils, and laboratory waste; perchlorate was also found onsite. This testimony discusses GAO's past work relating to remediation efforts at FUDS and military munitions sites to provide context for issues at Spring Valley. Specifically, it addresses: (1) the impact that shortcomings in information and guidance can have on decision-making; (2) the impact that incomplete data can have on cost estimates and schedules; (3) how funding for a particular site may be influenced by overall program goals; and (4) how better coordination can increase public confidence in cleanups and facilitate effective decision-making. GAO has made several prior recommendations that address these issues, with which, in most cases, the agency concurred.