Casualities resulting from flooding of industrial sites

Aim of this study was to get insight into the number of possible casualties that could be expected as a consequence of flooding of industrial sites. First a literature study was carried out using a database containing more than 17000 industrial accidents. From the literature study it could be concluded that only high-energy floods (i.e. high flow velocities) (were reported to) cause calamities (like fire and explosions) with casualties. Floating of tanks was observed n certain cases, and in addition to (storage) tanks, pipelines were vulnerable objects. No effects of toxic substances released and subsequently dispersed as a result from floods are reported. Secondly, a calculation of the expected number casualties was carried out for a simulated flooding event near the city of Krimpen aan de Lek in the Netherlands, using generally recognized principles and models applied during quantitative (safety) risk assessment studies (software program EFFECTS version 5). Only one site, where sufficient amounts of dangerous substances were stored, was found to be located such that a significant release could be expected. This was a location where 86 tons of ammonia (NH3) was present. Under unfavourable atmospheric conditions release of this volume could result in over 2000 deaths, and many more people needing medical attention. More realistic conditions, under which a dyke breach could be expected could result in about 55 casualties. Although flood conditions might be such that a release could occur, local safety) measures taken significantly reduce the probability of occurrence of such a scenario