Three serious accidents occurred in three dynamite manufacturing plants within three European countries during a relatively short time period triggering the question of effective external learning. The article discusses the lessons for the prevention of accidents learned from retrospective comparative analysis. It advocates for a better process for learning lessons. It attempts to show how a two level approach to accident analysis may help to reveal a common deeper learning hidden under diverse routine lessons. (C) 2016 Elsevier Ltd. All rights reserved.