A simplified method for the estimation of individual risk

A simplified method for estimating individual risk is presented. The method described is a development of other semi-quantitative approaches such as the risk matrix or Layer of Protection Analysis (CCPS, 2001). The method provides a simplified means of obtaining a conservative estimate of the individual risk to members of defined population groups. It can also be used to identify those event outcomes contributing most to the risk for each of the population groups specified, and may be used as a screening tool to identify areas for further analysis. The method may be implemented within a spreadsheet. However, the effort involved in using the method increases rapidly as the numbers of event outcomes, population groups and hazardous material locations are increased. It is recommended that use of the method be considered when: the number of event outcomes of interest is modest (50-100); the hazardous materials on site are found at a few discrete locations (1-3); and the number of population groups of interest is small (five or less). This paper and the work it describes were funded by the UK Health and Safety Executive. Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect ERM or HSE policy.