Most of the adverse impacts on man and/or the environment result from routine human activities such as the process industry, electricity generation and use, transport and agriculture (hazards, i.e. sources of risk). Apart from such essentially technological hazards, possibly resulting in "accidents", human health and the environment can also be affected by natural hazards, possibly resulting in "disasters", such as earthquakes or floods. This paper examines current trends in the risk sources and occurrences of four classes of such types of undesired events, entailing largely involuntary risk (e.g. neither car-driving nor smoking): major accidents at fixed installations in the process industry, incidents/accidents at nuclear installations, marine transport and offshore installation accidents, disasters caused by natural hazards and their potential exacerbation by human activities. It aims to provide an integrated overview of such events in Europe ( equivalent to 15 EU Member States, 4 EFTA, 13 PHARE, 7 TACIS and 5 other South and South Eastern European countries) during the last decade, estimating and interpreting trends in the number of risk sources and accidental events. For each type of event, specific "accident" definitions are given, illustrating the differences in the perception of the respective risk.