These days leakage incidents of toxic materials cause serious effects on the nearby residents as well as the workers around the accidents accompanying massive material losses and human damages through widening influential areas. The risk measure through adequate quantitative analysis as well as the qualitative analysis of the leakage incidents of toxic materials becomes an urgent issue. The damage of the leakage incident on the surrounding area of the dangerous toxic material facilities was calculated quantitatively by adopting several models in this research. First, the calculations of the leakage velocity from the factories were performed by using source model for the assessment of the influential area, and the damages on the nearly residents were calculated by using the dispersion model and the effort model. The probability of the Incidents was computed based on "The manual for classification and priorization of major incidents" published by IAEA( International Atomic Energy Agency ). Above calculated damage area and incident probability were further adopted in this study to induce the individual and societal risk, quantitatively. The calculated data of the real Incident of the toxic material leakage showed reasonable agreements to the actual damage of the incidents, which showed a validity of this study. The result of this study might be a helpful measure for predicting damages and preparing safety systems for similar kinds of incidents.incidents.