Chemistry Reference
In-Depth Information
of casualities among workers exposed to phosgene in the past, as well as the occu-
pational hazard assessment of phosgene, have been reported [6-8].
8.1.1
Laboratory and Kilolab Handling and Monitoring of Phosgene
Because of its corrosivity and high acute toxicity, phosgene should be handled
using the ''basic prudent practices'', supplemented by additional precautions for
work with compounds of high toxicity. Laboratory personnel intending to use
phosgene should be fully acquainted with its toxicity and reactivity, and the pro-
tective measures associated with this particular type of chemical. In addition, the
workers' colleagues should be familiar with the hazards and the necessary rescue
and first aid procedures.
Before starting laboratory work with phosgene, it is recommended that the indi-
vidual is equipped with fresh-air breathing apparatus, a bottle of strong ammonia
(or an alternative reagent) for leak testing, and a supply of 10% aqueous ammonia
solution (or 15% sodium hydroxide solution) for decontamination purposes [1].
In particular, laboratory work with phosgene should be conducted in a suitably
effective fume cupboard, and splash goggles and impermeable gloves should be
worn at all times. It is advisable to attach detector tapes (such as filter papers pre-
viously dipped in a solution of 5% 4-(dimethylamino)benzaldehyde and 5% N,N-
diethylaniline in ethanol) to the fume cupboard face. Any emission of phosgene
may then be noted from the characteristic color change (yellow to blue). Notices
should be placed nearby to warn that phosgene is being used. All gas bubblers, or
other vessels, through which phosgene has been passed should be labeled so that
other workers are not exposed to the residual phosgene unwittingly [1]. Flow rates
of phosgene gas and amounts of liquid material should be kept to the minimum
practical amount. Vacuum pumps should be protected by solid sodium hydroxide
traps. In the laboratory, gaseous phosgene can be conveniently metered by cali-
brated flow meters of stainless steel construction; electronic mass flow meters are
commercially available for applications where accurate readings are required. It
has been found that flow meters suitable for use with chlorine may also be used,
after calibration, to meter phosgene [1].
Containers of phosgene solutions should be stored in secondary containers, and
phosgene cylinders should be stored in a cool, well-ventilated area separate from
incompatible materials.
In the event of skin contact, immediately wash with soap and water and remove
contaminated clothing. In the case of eye contact, promptly wash with copious
amounts of water for 15 min (lifting upper and lower lids occasionally) and obtain
medical attention. If phosgene is ingested, obtain medical attention immediately. If
phosgene is inhaled, move the person to fresh air and seek medical attention at
once.
In the case of an accidental release of phosgene gas, such as from a leaking cyl-
inder or associated apparatus, evacuate the area and eliminate the source of the
