CONSEQUENCES OF EXPOSURE TO TOXIC GASES FOLLOWING INDUSTRIAL DISASTERS

Acute toxicity data are important in risk analysis. In this paper, recent developments in consequence modelling, reported in the so-called Green Book (published by the Dutch Ministry of Housing, 1990), are presented. The Green Book offers a simplified approach to determine probit functions for man, based on a relatively limited set of toxicity data. The determination process consists of two steps: (1) estimating a human LC50 from animal data, taking into account interspecies differences and the amount of information available; (2) calculating the probit parameters, based on a value of 1 for the slope of the probit function, which is a conservative assumption with respect to the variation in vulnerability of a human population exposed in emergency circumstances. The probit functions thus derived are a step towards more reliable vulnerability models. The extrapolation of animal data to human data contributes substantially to the uncertainly in risk analysis results. To improve this situation, research into the mechanisms of behaviour of the chemicals in the body is required.