A terrible explosion of ammonium nitrate, killing 30 people, occurred on 21st September 2001, in Toulouse, in AZF plant belonging to Grande Paroisse Company, TotalFinaElf Group. The manufactured chemicals in the plant were mainly ammonium nitrate, ammonium nitrate-based fertilisers and other chemicals including chlorinated compounds. The origins of the accident haven't found yet an agreement among investigators (company, justice). The aim of this paper is to provide abroad an overview of some lessons learnt on that accident, from many perspectives, following the national debates and parliamentary enquiry as well as the various technical accident investigations. (C) 2004 Elsevier B.V. All rights reserved.