AGRICULTURAL CHEMICALS IN RELATION TO HUMAN HEALTH’ 
Wayland J. Hayes, Jr.’ 
(Abstract) 
Pesticides promote health directly through the control of vector-borne diseases and 
indirectly through increased and improved agricultural production. On the contrary, the 
extensive use of any biologically active chemical implies a potential hazard which has 
to be evaluated. Production and use of these materials have increased greatly since 
World War II. In the United States alone, the annual production of synthetic organic 
pesticides, which were essentially unknown before DDT, reached a level of 569,927,000 
pounds in 1956. While this production of these synthetic materials has increased from 
essentially zero in 1942, production of the older, largely inorganic, pesticides has shown 
only a partial decline. Although something less than 200 basic chemicals are really 
important as pesticides, the situation is complicated for the practicing physician by 
the fact that thousands of different formulations of them may be labeled and soldina 
single country. The situation is further complicated by the fact that pesticides are now 
applied in ways which were either unknown or uncommon a few years ago. An example 
is the extensive use of aircraft for spraying operations. 
The way in which a compound is used may contribute more to its danger than its 
inherent toxicity contributes. Extensive experience has shown that pesticides may be 
used with very few accidents provided scrupulous attention is paid to their labeling and 
use. The death rate from poisoning caused by all pesticides in the United States is 
slightly less than 0.09 per hundred thousand population. Strangely enough, most of the 
fatal accidents in this country still involve the older pesticides. For example, in 1956, 
there were a total of 152 accidental deaths caused by all pesticides. Of these, 104 were 
caused by compounds older than DDT, including 54 caused by arsenicals alone. Over 
half of the cases occur in children. Thus in 1956, 94 of the 152 cases were in children 
under 10 years of age and 78 were in children under 3. Both the kinds of compounds 
involved and the predominance of cases in children indicate the possibility of real 
improvement if people can be educated to use these materials with even greater care. 
The safety record in some other countries is not so favorable, especially in connection 
with the newer compounds. It appears likely that improved labeling and improved regula- 
tion of use in those countries would help to remedy the situation. 
Information on morbidity is far less precise than that on mortality. In one study in 
which only serious cases were counted, the ratio of fatal to nonfatal cases associated with 
poisons was 1:13. In another study in which every report of trouble was counted as a 
case, the ratio was 1:750. The ratio is commonly estimated as 1:100 and this comes 
as close to the truth as is possible at this time. One gets the impression that the newer 
pesticides cause more nonfatal accidents than the older compounds cause. This is what 
one would expect from the amount ofthe various compounds used. However, the conclusion 
must be taken with reservation because reports of fatal poisoning by pesticides in the lay 
and technical press are chiefly concerned with the newer compounds and yet the official 
statistics show that in this country the majority of cases are caused by the older com- 
pounds. 
1From the Technical Development Laboratories, Technology Branch, Communicable Disease Center, Bureau of State Services, 
Publication Health Service, U, S, Department of Health, Education, and Welfare, Savannah, Ga, 
A review by the speaker entitled '’Pesticides in Relation to Public Health,'" Ann, Rev, Entom, 5: 379-404, 1960, Annual 
Reviews, Inc., Palo Alto, Calif. A review by J, M. Barnes entitled ‘Toxicity of Pesticides,'' Bul. Hygiene 34: 1205-1219. 
December 1959, 
, 2Medical Director and Chief, Toxicologist, Communicable Disease Center, Public Health Service, U. S, Department of 
Health, Education, and Welfare, Savannah, Ga, 
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