40 CIRCULAR 3 6 9, U. S. DEPARTMENT OF AGRICULTURE 



Avood borers are involved, when the exposure should be at least 48 

 hours. If any of the other fumigants are used, the following dosages 

 should be applied per 1,000 cubic feet of space: Ethylene oxide, 2 

 pounds; ethylene oxide-carbon dioxide mixture, 20 pounds; carbon 

 disulphide, 5 pounds ; chloropicrin, 1 pound ; or carbon tetrachloride, 

 80 pounds. 



FURS AND GARMENTS 



The protection of furs and fur garments in storage by fumigation 

 instead of cold storage is becoming more and more common. The 

 method consists merely in storing fur garments in tight rooms (fig. 

 35) that are so arranged that they can be fumigated regularly. The 

 fur garments are fumigated in a small fumigation vault (figs. 2 and 

 28) before being placed in the storage rooms (fig. 36). 



CONSTRUCTION OF STORAGE ROOMS 



The large storage rooms may be of any type of construction that 

 is sufficiently tight for fumigation purposes. Usually they are of 

 concrete or of hollow tile covered with Keen's cement. The surface 

 should be finished with 2 or 3 coats of gas-resistant paint. Large, 

 shallow evaporating pans are fastened along the walls near the ceil- 

 ing. These pans are connected by pipes to the storage tank (fig. 

 37) containing the fumigant. If ethylene dichloride-carbon tetra- 

 chloride mixture is used as the fumigant, it can be run into the 

 evaporating pans by gravity or by the use of a small compressor. 

 If ethylene oxide-carbon dioxide or methyl formate-carbon diox- 

 ide mixture is to be used, the evaporating pans are unnecessary, and 

 a piping system with one or several spray nozzles or cones should be 

 used instead. The cylinders containing one of these mixtures with 

 carbon dioxide are connected to the piping system outside of the 

 room (fig. 27), and the fumigant is applied by merely opening the 

 valve on the cylinders and allowing the required poundage to be 

 discharged. 



The door of the storage room is usually of the safe or refrigerator 

 type, AA-ell gasketed so that it will be airtight. An adequate venti- 

 lating system must be installed, so that the gas can be quickly re- 

 moved after the fumigation. As in the case of small fumigation 

 vaults, the ventilating stack should extend well outside the building. 



In cold climates there should be some means of heating the storage 

 room to at least 70° F. during the fumigation. 



If it is necessary to enter the storage room while it is under fumi- 

 gation, the operator should wear a gas mask equipped with a canister 

 designed for protection against the particular gas that is being used 

 and should remain in the room only long enough to obtain the 

 garment needed. 



DOSAGES 



For the fumigation of the large storage sections a dosage of 14 

 pounds of the ethylene dichloride-carbon tetrachloride mixture, 20 

 pounds of ethylene oxide-carbon dioxide mixture, or 28 pounds of 

 a methyl formate -carbon dioxide mixture, per 1,000 cubic feet of 

 space and an exposure of at least 48 hours should be used. 



