Abstract niet beschikbaarIn the framework of BNS (policy notice regarding the regulation of ionizing radiation) the maximum permissible lethal risk of 10 -6 a -1 for a single source of ionizing radiation is exceeded in the Dutch population for exposures due to discharges of a thermal phosphorus plant, the phosphate fertilizer industry and due to a consumerproduct (gasmantles for lighting). Two kinds of "critical" groups are considered, one because of geographical factors and an other because of special behaviour (diet etc.). Both have a maximum risk for all sources of ionizing radiation of 5 to 6 x 10 -6. A combination of both factors could result in a maximum risk of 8 x 10 -6. For about 98% of the Dutch population however the range in risk estimate due to exposures to sources of radiation as considered in BNS is from 0.3 to 1.5 x 10 -6 a -1.DGM/