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The cans or other receptacles containing the cyanid of potash 
should be plainly labeled ‘Poison!’ and each operator should 
become thoroughly familiar with the dangers which may attend a 
failure to carry out directions explicitly. 
POSSIBLE DANGERS IN USE. 
As soon as the bag containing the cyanid is dropped into the 
generator the operator passes quickly to the next generator, and so 
on. It is not safe to linger under any circumstances or to return in 
case of any omission. Any deviation from the set rules may mean 
the loss of life. 
The residue in the fumigating generator after the operation is 
completed consists of sulphate of potash, sulphuric acid, and water. 
Sometimes if the chemicals are not of the proper strength or are not 
properly combined a certain amount of cyanid of potash remains and 
hydrocyanic-acid gas is given off. This residue is an element of 
danger and should not be left in the generators after use, but promptly 
poured or thrown into a sewer trap or buried. The generator should 
then be thoroughly cleaned in running water. 
A question often asked by persons contemplating the employment 
of the hydrocyanic-acid gas method. of treating buildings is as to 
whether it is dangerous to the contents. It is apt to tarnish, though 
not permanently, polished brass and nickel when exposed to its action. 
Where such fittings can be conveniently removed it will save trouble, 
otherwise they may be treated after fumigation as if tarnished 
through any other cause. Liquid or moist food materials, such as 
milk or meats, are apt to absorb the gas and should therefore be 
removed. 
It is not positively known that fires are an element of danger, but 
persons experienced with this process are united in the opinion that 
to avoid the possibility of risks all fires, gas jets, and the like should 
be turned off.. There is a possibility of explosion when a gas is gen- 
erated in a tight inclosure, hence the precaution. 
GENERAL CAUTIONS. 
After what has been said of the deadly nature of hydrocyanic-acid 
gas it should be added that there is really no danger if the directions 
given in this publication are carefully carried out. to the letter and | 
the vapor is not inhaled. Even to taste the salt might have fatal 
results, and it is dangerous to inhale much gas, as this might cause 
of Agriculture, have successfully used this gas for fumigating rooms and buildings. 
It is in general use as a greenhouse fumigant and for nursery stock and the names of a 
hundred persons could be mentioned who have had practical experience with it. 
[Cir. 112] 
