Chemical Agents of Opportunity for Terrorism: TICs & TIMs

Chemical Agents of Opportunity for Terrorism
Training Support Package
Participant Guide
Slide 42
Chemical Agents of Opportunity for Terrorism:
TICs & TIMs
Phosgene
Odor threshold:
0.5 - 1.5 ppm
10 min AEGL -2:
0.60 ppm
10 min AEGL -3: 3.6
ppm
Module One – Toxic Industrial Gases as Terrorist Threats
42
The colorless gas, phosgene, has the odor of moldy hay or green corn. However,
recognition of odor is reliable only around a concentration of 1.5 ppm, a concentration at
which injury is already occurring.
Severe, but delayed-onset, pulmonary injury can be expected after a relatively short
duration of exposure at levels that may not be appreciated by smell. Additionally,
olfactory fatigue can occur, further impairing odor recognition.
AEGL-2 is the concentration above which exposure would be expected to result in
increasingly severe symptoms as exposure continued, with impairment of self-rescue.
Above AEGL-3 concentrations, life-threatening symptoms are expected.
Olfactory fatigue is a common, normal experience. It is an adaptive response in humans
– to both noxious and non-noxious agents. As an example, the aroma of fresh-baked
bread is more noticeable when first entering a room than several minutes later. With
some chemical agents, it is thought that the cellular toxicity of the compound itself (e.g.
hydrogen sulfide) contributes to the loss of odor recognition.
The posters on the slide were used in World War II military training to increase awareness of
soldiers, medical providers, and the general community of various aspects of chemical warfare.
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