INDUSTRIAL FUMIGATION AGAINST INSECTS ^\ 



methyl formate with carbon dioxide are applied through a piping 

 system and can be administered by connecting the cylinder to the 

 system (fig. 26) and opening the valve. If the cylinder is placed 

 on a platform scale, it is an easy matter to let in the quantity desired. 



USE OF OTHER FUMIGANTS 



Various other fumigants, not suitable for warehouse fumigation, 

 can also be used successfully for vault fumigation. These are car- 

 bon disulphide, ethylene oxide, ethylene dichloride-carbon tetrachlo- 

 ride, and carbon tetrachloride. 



CARBON DISULPHIDE 



Carbon disulphide is a colorless, volatile liquid, which boils at 

 114.8° F. On exposure to air it evaporates, forming a heavy vapor 

 that is very toxic to insects. 



It is applied by pouring the liquid into the evaporating pan of a 

 vault at the rate of about 5 pounds per 1,000 cubic feet of space. If 

 the vault is not tight or if highly absorbent commodities are being 

 treated, the dosage should be increased proportionately. It is not 

 uncommon to use from 20 to 30 pounds per 1,000 cubic feet. 



The vapors of carbon disulphide, when mixed with air in certain 

 proportions, are highly inflammable and explosive; hence this fumi- 

 gant should be used only where the fumigation vault is isolated 

 from other buildings, and where the fire hazard can be controlled. 



Mixtures of carbon disulphide with other chemicals, such as carbon 

 tetrachloride and sulphur dioxide, for the purpose of reducing the 

 fire hazard are now on the market. Although not absolutely nonin- 

 nammable, they can be used with comparative safety. Their efficacy 

 is directly proportional to the carbon disulphide content, and they 

 should be used accordingly. 



The vapors of carbon disulphide are poisonous to human beings if 

 breathed for an extended period. Exposure to light concentrations 

 may induce a feeling of giddiness, which, however, will quickly pass 

 off on coming out into the fresh air. Small quantities of carbon 

 disulphide can be handled without danger by the ordinary person, 

 although persons having any heart trouble should take little part 

 in its application. 



Carbon disulphide ranges in cost from about 6 cents a pound in 

 500-pound lots to 30 cents a pound in 1-pound lots. 



CARBON TETRACHLORIDE 



Carbon tetrachloride is a colorless, volatile liquid having a boiling 

 point of 170° F. Its vapors are noninflammable, and therefore it 

 is sometimes recommended as a fumigant in place of carbon disul- 

 phide. 



It is not very effective when used alone against insects that infest 

 stored products and should be chosen only when no other fumigant 

 will do. Its chief use is for mixing with more toxic fumigants to 

 reduce the fire hazard. 



To be at all effective, it must be used at a temperature of 75° F. or 

 higher, and at the rate of at least 30 pounds per 1,000 cubic feet of 

 space. It is applied by pouring it into the evaporating pan of the 



