Chemistry Reference
In-Depth Information
leak if this can be done safely. Remove the cylinder to a fumehood or remote area if
it cannot be shut off. In the event of a spill of a phosgene solution, soak up the
solution with a spill pillow or absorbent material, place in an appropriate container,
and dispose of properly. Full respiratory protection and protective clothing will be
necessary in the event of a spill or release in a confined area.
Excess phosgene and waste material containing this substance should be imme-
diately deactivated in the hood by treatment with ethanol or ethanolic ammonia.
Aqueous solutions of phosgene should be treated in the fume cupboard with an excess
of 10% aqueous ammonia (or 15% sodium hydroxide solution), and allowed to
stand until all the phosgene has been neutralized before running to drain. Solu-
tions of phosgene in water-immiscible solvents should be destroyed with ethanolic
ammonia. Decontamination of rubber tubing should be carried out by immersion
in aqueous ammonia prior to disposal in sealed plastic bags. An e
cient way to
destroy phosgene gas is to catalyze the hydrolysis reaction on a bed of charcoal over
which an excess of water is passing.
To ensure accurate compliance with regulations concerning the laboratory han-
dling of phosgene and the corresponding safety procedures, it is obligatory to con-
sult the national legislations on this matter, such as the recent Toxic Substances
Control Act (TSCA) of the United States, and the various National Laws based on
the EEC Sixth Amendment (Dangerous Substances). The legislation and codes of
practices affecting compressed gases in general (for the United Kingdom) have
been described by the British Compressed Gases Association [1].
8.1.2
Handling and Monitoring of Phosgene in Large-Scale Chemical Processing Plants
Comprehensive safety precautions are essential in facilities in which phosgene is
manufactured, stored, or processed in any way. Techniques to control occupational
exposure to phosgene must be assessed, and major accidents should be prevented,
literally, at all costs. These requirements are enforced by legislation in most in-
dustrial nations. Although the recommended practices are, in part and of necessity,
of a general nature for working with toxic gases, it is imperative that these, or
similar, practices are followed when working with phosgene. Personnel should be
protected from liquid phosgene by protective clothing that is impervious to phos-
gene, and exposure to the gas in concentrations above the recommended limits
should be prevented by the use of suitable gas masks or air respirators.
Owing to the poor warning properties of the gas to the human senses, automatic
continuous monitors equipped with alarm systems are recommended. Skin and
eye contact with phosgene should be avoided, but contaminated clothing should
be removed immediately and decontamination effected by washing. Emergency
showers should be provided in any facility in which phosgene is stored, used, or
manufactured [9]. Personnel engaged in the handling of phosgene should be
trained to recognize its odor and instructed in the application of protective mea-
sures and first aid and emergency procedures [10, 11]. In particular, personnel
