’Catastrophes are not accidents.’All complex organizations can take steps to prevent catastrophe by enlisting the new scientific study of danger. The author is a member of the Scientific Committee of 1′Institut Européen de Cindyniques and Directeur général adjoint of L'Union des Assurances de Paris. This article is part of a presentation made to the 1992 Paris Conference of the European Business Ethics Network, of which the author is a Council member. The subject of the Conference was the role of business in the shaping of cities, but the author's reflections on learning from risks are of considerably wider application