The consequences of the toulouse disaster on september 21, 2001, were quite severe : 30 fatalities, estimates of 10 000 physical injuries, 14 000 people suffreing from post-traumatic acute stress, 27 000 housings damaged and 1.5 to 2 billion euros of material damage. The public did not accept the restart of large chemical plants embedded in the city. The historical trends in LUP and vulnerability of populated areas were an important cause for the severity of the consequences. The Toulouse accident initiated a large debate and many thoughts ending up with the proposal of a new regulatory framework to improve the risk management system.