82 CIRCULAR 9 7 7. U. S. DEPARTMENT OF AGRICULTURE 



The Fish and Wildlife Service, the Public Health Service, the 

 Tennessee Valley Authority, and the Department of Agriculture have 

 conducted investigations to determine the effects of insecticides on 

 wildlife, fish and other aquatic life, and on beneficial insects. 



NATURE OF HAZARDS 



Some of the materials described in this circular must be applied 

 directly to the body. Other materials, not intended for direct applica- 

 tion to the body, must be handled in highly concentrated form and are 

 dangerous if accidentally spilled on the body. To destroy certain 

 disease vectors or pests, the treatment of living quarters is necessary. 

 The use of insecticides and repellents for controlling insects of medical 

 importance, therefore, results in unavoidable exposure of man to 

 chemicals used in this manner. 



Other treatments are made over extensive areas where man or 

 animals might be exposed to the chemicals by contact, inhalation, or 

 ingestion. In such varied uses consideration must be given not only 

 to acute but to chronic poisoning. 



The most important factors to be considered in appraising the 

 hazard of a given chemical treatment are (1) its acute toxicity, 

 (2) accumulative or chronic toxicity, (3) composition of the formu- 

 lated material, (4) concentration of toxicants handled in mixing or 

 applying the treatment, (5) amount of a given chemical that must be 

 applied to achieve insect control, (6) frequency of application, (7) 

 conditions under which the chemical is applied and degree of exposure 

 to the residues, and (8) physical and chemical properties of the 

 material. 



The inherent acute toxicity of a material is obviously the most 

 important criterion for estimating its hazard in handling, because 

 most of the items used by the military are, for logistical reasons, 

 packaged in highly concentrated form. If safe handling procedures 

 are developed and practiced, the relative hazard of the material is then 

 governed largely by the other factors. 



Sometimes the more toxic chemicals are used in such low con- 

 centrations and applied in such small amounts that the risk involved 

 in their use is less than that of other less toxic chemicals that must be 

 applied in larger amounts. 



Those responsible for recommending or supervising the use of insecti- 

 cides and repellents should make every effort to obtain information 

 on then toxicity and to encourage their proper and safe use. 



GENERAL PRECAUTIONS 



It is a sound safety measure to regard all insecticides as hazardous 

 to man and animals. The fact that they kill insects suggests that 

 they are likely to be harmful to man and animals under excessive 

 exposure. Kerosene, xylene, methylated naphthalenes, and other 

 solvents used in preparing many insecticide formulations are them- 

 selves sufficiently toxic to cause illness or even death if there is careless 

 exposure to them. Improper use of insecticides may also be harmful 

 to animals, fish, and other beneficial organisms. Insecticides or 

 solvents may injure plants if improperly used. 



