Chemical Agents of Opportunity for Terrorism: TICs & TIMs

Chemical Agents of Opportunity for Terrorism
Training Support Package
Participant Guide
Slide 22
Chemical Agents of Opportunity for Terrorism:
TICs & TIMs
Ammonia: Physical Properties
• Colorless gas with pungent odor
• Low odor threshold; good warning properties
• Highly water soluble
• Boiling point – 33°C
• Vapor density 0.6 (lighter than air)
• Combustible in narrow range
• Highly reactive gas
Module One – Toxic Industrial Gases as Terrorist Threats
22
Anhydrous ammonia at standard atmospheric pressure and temperature is a colorless
gas with an extremely pungent odor. It has high water solubility causing irritation on
contact. This combined with its low odor threshold (5-50 ppm) result in good warning
properties. (NIOSH TWA 25ppm). When anhydrous ammonia escapes from a
pressurized system, it may appear as a white plume. It is combustible at a concentration
of 15-25%; but pressured canisters can easily explode in heat and fires or with impact –
as occurs in railroad crashes. Note that it is lighter than air, but the density of a recently
released pressurized liquid is higher, so it may continue to “hug the ground” near site of
release.
December 2008 Version 2.0 Page 146