Facts and fallacies involved in the epidemiology of isocyanate asthma.

Personal experience and analysis of the medical literature on isocyanate asthma shows, that the reported incidence of this disease varies between 0 and 25%. Reasons for differences in observed incidence are intensity of isocyanate exposure, criteria for diagnosis, mode of calculation, sensitizing capacity of different isocyanates, individual predisposition and confounding factors (adjuvants). There is no geographical or ethnical prevalence. Work places at risk are those with isocyanate concentrations above 20 ppb (ceiling).