In the context of the environmental evaluation of the projects, the risk analysis of major technological accidents allows to integrate the aspect of the safety into the governmental decision-making as for the acceptability of the subdued projects. The risk analysis of major technological accidents joins in a wider progress of management of the risks. its realization allows to know the potential accidents associated with the setting-up or the presence of an installation. The knowledge of the consequences and the risks for the populations, the environment and the surrounding territories contributes to a better management of these by their reduction, the implementation of security measures and enfeeblement, the setting up of a planning of urgent measures and a program of management of risks adapted to the nature of the identified major potential accidents. The proposed approach in this thesis, combines the analysis of the risk, the process and the numerical simulation; by studying and assessing the fire consequences on the environment, throughout the life cycle of an installation, in normal and accidental situation ( emergency phase) and beyond (phase post-accident). This combination is realized by tools of analysis, evaluation of the environmental impacts and the dispersion of pollutants, by leaning on the complementarities between these analyses. First, it allows integrating the qualitative results of the risk analysis by AEE- Accidental Aspect into the studies of the product life cycle by the LCA- Fire. She allows, then, to use the quantitative data stemming from the ILC as entries of a Dispersion Numerical Model. This crossing of knowledge helps to supply to the decision-makers of elements allowing to understand and to estimate the stakes, to identify the solutions and to discuss criteria to be considered for a better management of a fire in opened environment and in an industrial territory.
