Comparison of different methodologies to estimate the evacuation radius in the case of a toxic release

A comparison of different methodologies used to estimate the evacuation radius, is presented. The evaluation is accomplished doing some modifications in the way of computing indoor concentration (taking into account the profile of outdoor concentration and the possible sorption into indoor surfaces) and toxic load. The casualties' probability estimation is made using the probit analysis, but a parallel analysis to assess the effectiveness of shelter in place, based on the AEGL-3, is also made with the aim of comparison and to confirm the results obtained with the probit analysis. Five substances of different toxicity (chlorine, methyl isocyanate, acroleine, hydrogen fluoride and mustard gas) are used to study the performance of one or another methodology, finding that for cumulative substances there is an overestimation with the method used by Catalonian government. Concerning meteorological conditions, larger distances were obtained when increasing the atmospheric stability.