INDUSTRIAL FUMIGATION AGAINST INSECTS 61 



Ethylene oxide, methyl formate, ethylene dichloride, carbon disulfide, 

 and carbon tetrachloride, either alone or in the combinations usually 

 recommended for fumigation work, are regarded as only slightly toxic 

 to man as he ordinarily comes in contact with their vapors, although 

 gas masks must always be worn if the fumigators must remain 

 exposed for appreciable periods. 



Approved gas masks, or commercial masks and canisters de- 

 signed to protect against the gas being used, are intended only 

 for use around fumigation operations and around equipment 

 used outside the bin or building and in places where light con- 

 centrations only may be encountered. They are not guaranteed 

 to protect the wearer against high concentrations of any fumi- 

 gant. Where it is necessary for human beings to enter places 

 where high concentrations are present, only an air-line mask 

 supplied with air from a safe source will afford complete pro- 

 tection. It is urged that this type of mask be used in all places 

 where concentrations higher than 2 percent may be encountered. 



Gas masks should be cleaned and sterilized after each use, par- 

 ticularly if it is likely that several people may wear them. Each 

 mask must be tested for leaks each time it is put on, by stopping up 

 the canister connection and drawing in the breath. If the facepiece 

 leaks, it should be adjusted to fit so that the normal movement of the 

 head will not cause it to leak. 



Besides wearing a gas mask, a fumigator should protect the 

 entire skin area if it is necessary to remain in the gas for more 

 than 5 minutes. Ordinary clothing affords little protection, as 

 it will absorb the gas. Coveralls made of "slicker" material, with a 

 hood fitting tightly around the gas mask, fastened tightly around the 

 feet and ankles and fitting tightly around the wrists over the wrists 

 of oiled leather gloves, constitute the best light-weight protection so 

 far designed. 



Never assume that a gas mask will protect. Obtain definite 

 assurance that it is equipped with a canister of chemicals pre- 

 pared to neutralize the vapor or vapors to be used. Attach a 

 fresh, unused canister to the mask unless the exact history of 

 the one already attached is known. Do not use a canister longer 

 than the period recommended by the manufacturer or after it 

 show signs of deterioration. Canisters for gas masks cost only about 

 $2 each ; there is no need to take chances. Do not permit familiarity 

 with a dangerous fumigant to lead to criminal carelessness. 



When a fumigator has left a building because of trouble with his 

 mask, the men and their supervisor should seek the cause of the trouble. 

 The gas mask should be cleaned and inspected, and then tested for 

 leaks by putting on the mask, holding the hand tightly over the 

 canister opening, and inhaling. If air is drawn in, the mask leaks 

 and the leak must be found. Adjusting the facepiece should be tried 

 first. If this fails to stop the leak, then the mask should be discarded 

 or sent to the factory for repairs. 



If the mask can be adjusted until it does not leak, a new canister 

 can be attached and the mask will be ready for use. However, if the 

 facepiece shows no leaks, and there is no leak in the canister connec- 

 tions, there are three other possible causes: (1) The canister may have 

 been used too long; (2) the concentration of gas may have been higher 



