Abstract

The findings of a diagnostic blood test for the presence of hexachloro-epoxy-octahydro-dimethanonaphthalene (H.E.O.D.) performed on whole blood obtained from operatives of plants manufacturing two chlorinated hydrocarbon insecticides, aldrin and dieldrin, and formulating products containing them and from dogs experimentally exposed to dieldrin have been reported. When clinical signs of poisoning were present, the concentration of H.E.O.D. in the blood was more than 16·0-17·0 μg./100 g. blood. In the absence of clinical signs of intoxication the concentration of H.E.O.D. found in the blood was less than these values. However, the concentration of H.E.O.D. found in several operatives and in two dogs who were without signs of intoxication was above these values. It is suggested that there is a concentration of H.E.O.D. in the blood of man and dog which is a threshold for intoxication. The value for the threshold concentration may be near 15·0-20·0 μg./100 g. blood. An individual man or dog with a concentration of H.E.O.D. in the blood greater than the threshold is in a critical condition requiring some factor or factors not yet determined to precipitate intoxication. The use of this blood test will assess the severity of occupational exposure and support the diagnosis in suspected intoxication.