The United Nations Environment Programme (UNEP) work on depleted uranium (DU) started in the summer of 1999 when UNEP carried out an assessment of the impacts of the Kosovo conflict on the environment and human settlements. As part of that review, UNEP conducted a desk assessment study of the potential effects of the possible use of DU during the conflict. In 2000, the North Atlantic Treaty Organization (NATO) provided UNEP with new information concerning the use of DU during the Kosovo conflict. This information included maps, the amount of DU ammunition used, and coordinates of the targeted areas. It enabled UNEP to carry out the first-ever international assessment on the environmental behavior of DU, following its use in a real-conflict situation.