Methodology often used to estimate the consequences of postulated nuclear reactor accidents was applied in an analysis of the SL-1 reactor accident, which occurred in January 1961. The work focused on use of the CORRAL and CRAC computer codes to predict radionuclide leakage from the accident and resulting downwind environmental contamination levels. Results were compared with findings developed from actual post-accident environmental sampling and analysis. The comparison indicated that the predictive capabilities of the two reactor accident consequence codes can be quite dependent on the input specifications for the analysis. In particular, the results show that the amount and the state of the initial source term is of considerable importance in determining the magnitude of the environmental contamination.