Toxic hazards in aerial application.

An analysis of the hazards acompanying the aerial application of toxic pest-control chemicals is presented. The nature of the chemicals, the symptoms of toxicity, recommended treatment, and suggestions for safe-handling, are discussed. The introduction of the chlorinated, cyclic hydrocarbons for large-scale use as agricultural insecticides somewhat less than two decades ago, marked the beginning of a new era in agricultural pest control. In the intervening years, new chemicals, many of them engineered for specific agricultural purposes, have appeared in rapid succession. The large number and wide variety of these compounds, and their new and unfamiliar chemical and toxicological properties, have brought a host of medical problems. The insecticides which were the farmer's first line of defense prior to the 1940's, presented no great toxicological threat. The compounds of arsenic, for instance, are dangerously toxic only when inhaled or taken by mouth, and these are routes of entry into the body which are relatively easy to protect. Mixtures of sulfur and lime are comparatively innocuous. Nicotine, derris, the pyrethrins and mercurials were never used for large-scale agricultural purposes as we now understand the term. There were no effective defoliants or weed-control chemicals. Therefore, when the chlorinated compounds appeared in the 1940's and the organophosphates shortly thereafter in the 1950's, neither farmers nor pest control operators were prepared for the higher intrinsic toxicity of these substances. Nor were they prepared for the appearance of symptoms without warning, due to a strange new hazard, absorption of the toxic agent through the skin. It is not surprising therefore, that a familiar pattern has emerged. Many poisonings have occurred in the first months or years following the introduction of the more potent pesticides into a region where they were previously unknown. This is the pattern which enabled two Japanese scientists to accumulate the histories of 6000 cases of parathion poisoning within the first 5 years following the introduction of this chemical into Japan for use in the rice fields (1). Ultimately, instruction, training, and experience reduce the incidence of such