INDUSTRIAL FUMIGATION AGAINST INSECTS 25 



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, since the 

 fumes are so heavy that they tend to concentrate on the lower floor. 

 If the floors cannot be made gastight, a greater concentration should 

 be applied on the upper floors. 



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

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

 the process of vaporization by applying the liquid in the form of a 

 spray or fine mist, or by using a mixture of equal parts of chloro- 

 picrin and carbon tetrachloride or trichloroethylene. At tempera- 

 tures above 70° F., however, satisfactory results can be obtained by 

 merety 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 the chloropicrin directly into the 

 machinery where the heaviest infestation is likely to be found. In 

 such cases the fumigant can be applied with either a sprinkling can 

 or an atomizer. One-pound cylinders of chloropicrin charged with 

 carbon dioxide, to which a short length of hose and a spray nozzle 

 are connected, can also be obtained for treating machinery. The 

 nozzles are inserted into holes bored into elevator legs or other parts 

 of the equipment, and the gas is released by opening a valve on the 

 cylinder. 



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 noninflammable, 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 (fig. 

 26). A cylinder of the mixture will empty itself in about 5 minuter 

 after the valve has been opened wide. 



When the valves are opened Avide. the force of the escaping gas 

 often causes the cylinders to topple over. To avoid this, the cylin- 

 ders can be lashed to the walls of any stationary object, or several 

 cylinders can be lashed together with the discharge vents pointing 

 in opposite directions. 



430°— 35 4 



