The purpose of the present analysis is to explore systematic ways to address the problem of how many accidents involving hazardous materials actually occur in Europe, and to make a realistic estimate. A framework for predicting the total number of accidents was therefore developed and applied. The analysis is based on 535 unique accident descriptions (of which 107 were fatal accidents) from seven accident databases covering the nine-year period from 1984 to 1992. The majority (70%) of the accident descriptions identified were found in one source only. This indicates that, at best, about 30% of all accidents described may be found in a single database. Two models were developed: the first model was based on ideas similar to ＇chemical reaction kinetics＇; the second was more related to ＇estimations of an animal population＇. The models predict an average of 87 accidents per year in contrast to the observed average of 59 accidents per year. For fatal accidents, the models predict an average of 14 accidents per year, and the observed average is 12.