The tests concerned with mammalian toxicity indicate that treatment of 
tobacco warehouses with DDVP at the rate of 10 grams per 1,000 cubic feet 
might constitute a hazard to workers, This judgment is based upon observed 
effects on cholinesterase levels of rats, monkeys, and humans, and upon air 
concentration values, The results of the tests at levels of 1 and 2 grams 
per 1,000 cubic feet were less clear-cut. However, indications are that at 
least the latter concentration might be too high for safety, since an effect 
from the dosage was seen on the cholinesterase level of exposed monkeys, Still, 
it should be noted that these monkeys were not only exposed continuously for 
7 days but also were exposed to the high concentrations of vapor occurring 
during the application of the insecticide and immediately thereafter. In 
contrast, laborers working in treated warehouses would never be exposed to the 
high initial concentration of vapors and they would be exposed for only 8 
hours, or less, in any one day, except under unusual circumstances, 
LITERATURE CITED 
(1) Durham, W. F., Garner, T. Be, McCauley, R. H., Sedlak, V. A., 
Mattson, A. M., and Hayes, W. J., Jre 1957. Studies of 
the toxicity of 0, O-dimethyl, 2, 2-dichlorovinyl phos- 
phate (DDVP). AMA Arch, Industrial Health 15: 30. 
(2) Mattson, A. M., Spillane, J. T., and Pearce, Ge We. 1955. 
Dimethyl 2, 2=dichlorovinyl phosphate (DDVP), an organic 
phosphorus compound highly toxic to insects. Jour. Agr. 
Food Chem, 33 3193 
(3) Nakamura, Ge Re 1955. Microdetermination of phosphorus. 
Anal. Chem. 23: 1830. 
(4) Tracy, Re Le, Gentile, J,, and Wenneis, J. Me 1956, 
Concentration of DDVP insecticide for the cigarette beetle. 
Paper presented at fourth annual meeting of Entomological 
Society of America, New York, N. Y. 
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