[en] Evaluation of radiological risk of uranium milling is based on identification and quantification of sources of release and consideration of dynamic coupling among the meteorological, physiographical, hydrological environments and the affected individuals. Dispersion pathways of radionuclides are through air, soil, and water, each demanding locally tailored procedures for estimation of the rate of release of radioactivity and the pattern of biological uptake and exposure. The Uranium Dispersion and Dosimetry Code (UDAD), a comprehensive method for estimating the concentrations of the released radionuclides, dose rates, doses, and radiological health effects, is described. Predicted concentrations and exposure rates are compared with experimental data obtained from field research at active mills and abandoned tailings