86 CIRCULAR 97 7, V. S. DEPARTMENT OF AGRICULTURE 



LINDANE 



Lindane is the name given to the practically pure gamma isomer 

 (99 percent) of benzene hexachloride. For the control of some insects 

 it may be used in smaller amounts than DDT, chlordane, and some of 

 the other chlorinated hydrocarbons. It does not have the objection- 

 able musty odor of technical BHC. 



Lindane is less toxic chronically than BHC. However, its acute 

 toxicity to man and animals, either orally or dermally. is higher than 

 that oi technical BHC or DDT. The median lethal oral dose for 

 laboratory animals averages about 125 mg. per kilogram of body 

 weight. Dermal applications are many times as toxic as those of 

 DDT. Emulsion or wettable-powder sprays containing as little as 

 0.05 percent of lindane may cause toxic symptoms in calves. Older 

 cattle may tolerate much higher concentrations. The physical condi- 

 tion of the animal affects its susceptibility to lindane. For example, 

 sheep in good condition may tolerate sprays containing 0.25 percent 

 of lindane, whereas extremely emaciated sheep may become poisoned 

 by concentrations as low as 0.03 percent. 



The Food and Drug Administration regards the chronic oral 

 toxicity of lindane to be about one-fourth that of DDT. Because it 

 is usually employed in low concentrations, food contamination from 

 sprays and dusts is less likely than from those containing DDT. 

 However, lindane vapors may be formed and recondensed on objects 

 and food, and thus offset this advantage. 



Lindane appears in milk of dairy cows that have been sprayed with 

 or have consumed the chemical in the diet. However, it does not 

 readily accumulate in the system and is eliminated from the body in 

 a much shorter tune than is DDT. 



The vapors of lindane are highly effective against insects. This 

 property is utilized to control flies, mosquitoes, and other pests by 

 volatizing lindane inside of buildings. However, the vapors on long 

 exposure or in high concentrations may also be toxic to people. 



Special Precautions in Using Lindane 



Avoid excessive dermal exposure, especially to oil solutions. 



In using lindane vaporizers in homes, do not expose people continuously 

 to the vapors for long periods. 



Restrict residual applications to spot treatments in living quarters for con- 

 trolling roaches, ants, and flies. In some parts of the world the treatment of 

 living quarters with lindane is required for controlling malaria or other insect- 

 borne diseases. However, it should be applied by experienced operators 

 under the supervision of responsible agencies. 



CHLORDANE 



The chronic toxicity of chlordane appears to be higher than that 

 of DDT although available data are not in agreement on this point. 

 The differences may be due to variations in the composition of the 

 manufactured product. 



The acute median lethal oral dose for laboratory animals is about 

 457 nig. per kilogram of body weight, which is higher than that of 

 DDT. When fed in the diet of laboratory animals 2.5 p. p. m. is 



