year, while a frequency of 10-11 or less is considered negligible.
A frequency in between these values is considered to warrant investigation of options to reduce the frequency. This large 'grey' area represents a margin between acceptability and unacceptability, to allow for the uncertainties associated with risk assessments, to allow for the consequences of cumulative exposure and to allow the two levels to be distinguished properly. This is in accordance with the overall approach taken towards setting risk limits in The Netherlands the negligible risk level is considered to be 1 per cent of the maximum permissible level.
Figure 30.1 - Societal risk limits adopted by The Netherlands
Source: VROM, 1990