INDUSTRIAL FUMIGATION AGAINST INSECTS 25 



man, and has an extremely irritating effect upon the eyes and respira- 

 tory passages of man. This last characteristic insures against the 

 possibility of anyone accidentally entering a building filled with gas. 

 A gas mask equipped with a canister especially designed for the pur- 

 pose must be worn when fumigating with chloropicrin. 



There are several methods of applying chloropicrin as a general 

 mill or warehouse fumigant. The simplest of them is to draw the 

 required quantity of liquid from the cylinder in which it is mar- 

 keted into a sprinkling can and sprinkle it over the floor or commod- 

 ity or into the machinery. It should not be applied directly on 

 painted or varnished surfaces. Where there are several stories to a 

 building, each floor should be sealed off from the others. 



Owing to the rather high boiling point of chloropicrin and conse- 

 quent slow rate of evaporation, it is sometimes desirable to hasten 

 the process by applying the liquid in the form of a spra}^ or fine 

 mist, or by using a mixture of equal parts of chloropicrin and carbon 

 tetrachloride or trichloroethylene. At temperatures above 70° F., 

 however, satisfactory results can be obtained by merely applying the 

 straight chloropicrin with a sprinkling can. 



In mills that are equipped with machinery for handling food- 

 stuffs, it may be desirable to apply a portion of the chloropicrin 

 directly into the machinery where the heaviest infestation is likely 

 to be found. In such cases the fumigant can be applied with a com- 

 bination of sprinkling cans, sprinkler bottles, sprayers, ladles, or tin 

 measuring cups. 



One-pound "automatic" cylinders of chloropicrin charged with 

 carbon dioxide are sometimes used for treating machinery. They 

 are supplied with a short length of hose ending with a spray nozzle. 

 The nozzles are inserted into holes bored into the machinery, and 

 the gas is released by opening a valve on the cylinder. The pres- 

 sure of the carbon dioxide expels the chloropicrin in a fine mist. 



An objectionable feature of chloropicrin is that considerable time 

 is required to ventilate a building after a fumigation. Because it 

 does not evaporate rapidly, it clings to fumigated commodities with 

 great tenacity. 



FUMIGATION WITH ETHYLENE OXIDE-CARBON DIOXIDE MIXTURE 



Warehouses and storage rooms that are of modern tight construc- 

 tion can be successfully fumigated with a mixture of ethylene oxide 

 and carbon dioxide. This mixture is put up in cylinders in the pro- 

 portion of 1 part by weight of ethylene oxide to 9 parts of carbon 

 dioxide. It is nonin flammable, and is not sufficiently toxic to human 

 beings to make its application unpleasant or dangerous. It leaves 

 no obnoxious odor or poisonous residue on the commodity fumi- 

 gated. The mixture is sold in 30- and 60-pound cylinders at prices 

 ranging from 14.5 to 16 cents per pound, f. o. b. the factory. 



The application of the ethylene oxide-carbon dioxide mixture is 

 exceedingly simple. The requisite number of cylinders are placed 

 in the room to be fumigated and the valves opened. The pressure 

 of the carbon dioxide automatically discharges the contents of the 

 cylinders in the form of a very fine mist, which vaporizes at once 



4964°— 37 1 



