The analysis of major accidents, the so-called case histories was, and still is, a subject that draws much interest. Analysing
the often, complex cause consequence relationships which make hazardous materials get released or start to react, stimulate the thinking. Unravelling the intricate chemical and physical phenomena is sharpening the mind. Much can be
learned. However, it proved not so easy to keep the knowledge living, since at the time there were no data banks and few
concepts and methods to condense experience into. Already at the first international symposium in Delft, the Netherlands in 1974 (Buschmann, 1974) the merits of ‘risk analysis’ were put forward and a discussion group tried to create some order in the flood of new terms. The day after this symposium, the vapour cloud explosion of the Nypro plant in Flixborough, UK, which over the years became one of the most extensively investigated accidents, proved once again how urgent the study of safety issues was at the time (Figure 1). The Working Party has, in the first years, spent quite some effort discussing the accident statistics, since it appeared that the incident rates (based on the frequency an employee was injured such that work time was lost) in the American industry were an order of magnitude lower than in Europe. Beside doubt whether the statistical basis was equal, there was the question of what are we doing wrong. The issue of the comparability was more or less cleared when rates could be compared of a same company with subsidiaries in Europe and the US. Differences seemed to be real. To improve safety, work had to be done on many fronts. More systematic studies were initiated. The Working Party under took study groups on risk analysis and human factors. The hazard and risk analysis methodology was described, the terms defined, and the directions for further development of methods and data collections determined. In the early 1980s the Commission of the European Community started to sponsor industrial safety research (Figure 2). The vapour cloud explosion phenomenon and the transportation of volatile, flammable materials along waterways where at
certain locations nuclear power plants were built, triggered this. Together with national funding the research developed
rapidly and various national research organizations started to co-operate on gas dispersion, vapour cloud explosion and
reactor run away.