The method described in this report provides a framework and suggests a quantitative approach to accomplish the setting of a standard with an adequate margin of safety in order to deal with the uncertainties of standard setting. The kernel of the suggested approach is a systematic assessment of the risks associated with alternative standards in a carefully defined sense. First, the method attempts to define terms precisely so that uncertainty about what a quantity means is not added to the inherent uncertainty about its value. Second, the output of the method clearly displays how a calculable risk varies with the particular choice made from a reasonably comprehensive set of representations of the primary uncertainties which give rise to the risk. In other words, the 'softness' of the risk calculations which results from the secondary uncertainties is dealt with directly in such a way as to give the decision-maker(s) a conception of its degree.