[Are pyrethroids harmless? Evaluation of experimental data].

Pyrethroids are synthetic insecticides which world-wide increasingly replace DDT, Lindane, Organophosphate-pesticides etc. in fields like agriculture, hygienics, household, wear- and building industry. Being lipophilic and strongly neurotoxic substances, a considerable health risk has been predicted in regard of pyrethroid applications. On the other hand the published experimental data are often interpreted as proof of a small, calculable and, therefore, controllable risk. The present paper attempts to specify the reasons for these contrary judgements with regard to the pyrethroid effects. Since the arguments of both sides are based on the same experimental data, first the scientifically unquestioned evidence about effects and stability of the pyrethroids is acquired and critically reviewed. The different arguments are in turn discussed in details by means of this evidence. It was demonstrated that the scientific understanding of the pyrethroid effects is incomplete, as far as that the health risk cannot be considered as calculable. Impairments of health caused by pyrethroid effects, particularly known from scientific investigations carried out in China but also occurring with increasing incidence in Germany, can, therefore, not be excluded anymore. As practical consequences, moreover, an obligation to complete publication of pyrethroid intoxications and an extensive health education of the public about the risks associated with pyrethroid applications are demanded.