In the field of risk prevention, research is often divided or partial. Research work -achieved or in progress - focuses on topics like technical risk assessment, organisation management or human factor : ergonomics, sociology, etc. But little work is dedicated to an integration of all these disciplines into a same methodology. It is yet obvious that an effective control of major accident risks depends on the ability of an organisation to consider and integrate every aspect of prevention. A separate control of either human factor, or safety technical barriers, or safety management is of course necessary, but does not guarantee a sufficient prevention level on its own. Effective prevention requires the control of every means available. From this statement, INERIS has started developing an original integrated method to control major accident risks of hazardous establishments under the scope of Seveso II directive. The method is currently tested with voluntary French SEVESO II establishments.