A later analysis concluded that some of the depleted uranium used during the war contained traces of plutonium and uranium 236¿neither of which occur naturally, but are created during nuclear fission. This discovery made the origins of the DU a hot political issue and raised additional health concerns because both materials are far more radioactive than regular DU. As it turned out, though, the traces of U236 were so small that they did not change the radioactivity of the depleted uranium; so too, the plutonium content varied from a negligible 0.8 to 12.87 becquerel per kilogram.
Although depleted uranium may not pose an immediate threat, because it is both radioactive and toxic, some action is warranted. Klaus Toepfer, executive director of the UNEP, sums up the recommendations made by the Balkans Task Force in 1999: "Highest priority should be given to finding pieces of depleted uranium and heavily contaminated surfaces. Measures should be taken for the secure storage of any contaminated material recovered.