Chemical Agents of Opportunity for Terrorism: TICs & TIMs

Chemical Agents of Opportunity for Terrorism
Training Support Package
Participant Guide
Slide 26
Chemical Agents of Opportunity for Terrorism:
TICs & TIMs
Worst-Case Scenario:
Likelihood of Occurrence
• WCS are considered unlikely because:
– assume a very large release occurring during worst -case
atmospheric conditions
– does not include active release mitigation such as water
deluge systems and automatic shutoff valves
• passive mitigation efforts included, such as containment dikes a
building enclosures
• However, with terrorist attack, more than one
process likely to be affected
nd
Module One – Toxic Warfare: Looking Beyond Conventional Chemical Weapons
26
The EPA’s regulations require that Risk Management Plan (RMPs) be developed by all
companies with large quantities of toxic chemicals on site. They should specify a worst
case scenario (WCS). The modeling features of WCS include calm wind conditions
(allowing uniform spread of agent in all directions from a release), and release of all the
substance involved in a single process or storage site without including any active
mitigation steps (attempts to control spread).
These conditions are all unlikely to occur, but as we will discuss later, the models are
designed for accidental releases. A terrorist release may involve multiple processes or
targets.
The use of a worst-case scenario is standard practice in modeling hazardous material
release responses and performing risk assessment. It allows an understanding of the
potential for an event, with a realistic endpoint for response preparedness. In the
situation of a real event, the response can be scaled as needed.
December 2008 Version 2.0 Page 31