Within the FASSET project, a review of existing programmes for the assessment of environmental risks from radioactive or hazardous substances was carried out in order to identify appropriate aspects that could be incorporated into the FASSET framework. The review revealed a number of different approaches, arising from the need to balance the information value of the assessment against the availability of data and the need to keep the assessment manageable. Most of the existing assessment programmes fit into a three-phase approach to environmental risk assessment: problem formulation, assessment and risk characterisation. However, the emphasis on particular assessment phases varies between programmes. The main differences between the different programmes are: the degree of specificity to a particular site, the level of detail of the assessment, the point at which a comparison is made between a criterion intended to represent 'what is acceptable' and a measured or predicted quantity, the choice of end-point for the assessment and the relationship between measurement end-points and assessment end-points. The existing assessment programmes are based on a similar general structure, which is suitable for use as a basis for the FASSET framework. However, certain aspects of the assessment of exposure and effects of ionising contaminants, e.g. dosimetry, require further development before incorporation into such a framework.