Results on estimation of modern radioecological situation at nuclear explosion «Chagan» based on large-scale cartographic studies (1:25 000) of a test area (4 km2) are presented. Maximum γ-irradiation doses were observed at bulk of ground surrounded a crater and at radioactive fall-outs extended to the North-East and to the South-West from the crater. Based on data on artificial radionuclide specific activity most part of soil samples were attributed to radioactive wastes according to IAEA and OSPORB. Natural decrease of soil radioactivity up to safety level due to 60Co, l37Cs, 90Sr, 152Eu, 154Eu radioactive decay and 241Am accumulation-decay will not take place in close 60 years at the area studied.