This report responds to your subcommittee's request that we examine Department of Defense (DOD) policies and practices regarding cleanup of environmental contamination at government owned, contractor operated (GOCO) plants, as a follow up to our previous reports that showed inconsistent policies and practices on cost sharing. We reviewed nine higher-cost case studies at the Defense Logistics Agency (DLA) and the military services (1) to assess the consistency of cost-sharing practices across DOD and (2) to compare the service cleanup estimates against DOD'S. Specifically, we identified the actions taken and the types of arrangements for sharing cleanup costs between the government and other responsible parties, and examined site-specific cleanup cost data.