This advice, on intervention levels for food following a radiological accident, is given in the context of recommendations from the International Commission on Radiological Protection (ICRP) and the regulations from the Council of the European Communities on intervention levels for food.
The Council regulations restrict radiation doses from food to low levels. Reduction of the Council intervention levels to more restrictive levels is therefore unlikely ever to be justified on the grounds of reducing radiation risk. However, the National Radiological Protection Board (NRPB) advised that, following a very severe accident, it could be justified to relax the Council intervention levels by up to a factor of 10.
For individual foods or radionuclides, where it could be demonstrated that individual doses would be restricted to levels of a few millisieverts, a greater degree of relaxation could be justified.
The regulations do not specify levels for drinking water supplies so UK Action Levels for water are recommended. In circumstances where replacement of supplies is extremely difficult, relaxation of the Action Levels by factors of 2 or 3 may be justified.
Both the Council intervention levels and the Action Levels represent a balance between the harms and benefits likely to arise from intervention; they do not represent a boundary between safe and unsafe levels. Consumption of food or water at concentrations in excess of these levels for short periods need not be a cause for concern.