Chemical Agents of Opportunity for Terrorism: TICs & TIMs

Chemical Agents of Opportunity for Terrorism
Training Support Package
Participant Guide
Module Six Summary
Unlike the general concept of chemicals poisoning, in which the onset is rapid and the source
identifiable, some toxins may have a delayed onset of symptoms. This could be beneficial to its
use as a covert weapon from the perspective of a terrorist. Allowing time for victims to leave
may seem like a “bad thing” to a terrorist, but in reality this complicates the epidemiology
(figuring out the cause of the problem and source) and makes clinical management more
difficult. More exposures may occur because there are no warning properties of exposure. In
acute onset toxins, most people will escape when those around them start to get sick. But if
nobody gets sick….nobody realizes they are being poisoned….and nobody escapes.
Chemical agents with a delayed toxicity onset can be organized and separated based on
route/scenario of exposure. Some are airborne (phosgene), food and waterborne (thallium,
organomercurials, radionuclides/radioactive metals), and environmental/ biopersistent agents
(dioxins, PCBs and PBBs).
Choice of a toxin with delayed onset not only allows time for the perpetrator to escape and
complicates diagnosis and response, but creates the potential for a large number of victims
which may result in overwhelming the health care system with large numbers of patients with
“medically unexplainable symptoms” presenting in dispersed fashion. This will contribute to
creating chaos and social terror. The delayed onset of these agents may mimic some biological
agents (anthrax, smallpox).
Thallium has many qualities that allow it to be used as a terrorist weapon and has a long history
of use as a homicidal toxin. The “classic triad” of gastrointestinal symptoms, paresthesias, and
alopecia is obvious only if you know about it. Most physicians are not aware of this syndrome
and will likely go looking in the wrong direction…..many other things cause painful neuropathy
(e.g., diabetes, HIV) but none are as acute in onset as that from thallium (days).
Organomercurials are examples of an agent used to raise fear and concern. It is widely believed
to be extremely toxic, although the majority of us are exposed to small doses on a daily basis. It
provides the opportunity to highlight the importance of physical state and chemical form in
determining toxicity. While elemental mercury is of minimal toxicity in is liquid form, when
inhaled following volatilization it can produce both irritant lung syndrome and neurotoxicity.
Although low level exposure to a vapor over a long period can produce neurotoxicity without
pulmonary abnormalities, this would not be a very effective terrorist weapon. Organic mercury
compounds (those in which Hg is bound to a carbon backbone) are widely used in industry and
science, and vary in toxicity from virtually none (as in organic mercury present in vaccines) to
devastating, as is the case with dimethylmercury. Depending on the specific organic mercury
compound, they can be absorbed by virtually every route, including dermal.
Even less toxic compounds which are biopersistent and whose detection is delayed (such as
the dioxins and other halogenated hydrocarbons) have enormous potential to cause fear and
overwhelm health care resources
Highly toxic substances whose onset of toxicity is delayed are currently readily available; these
delayed effects can be used to affect large numbers of people before an event is discovered.
The delay in onset of toxicity aids a would-be terrorist in avoidance of detection and escape
while serving the purpose of creating uncertainty and panic. Due to the dramatic increase in
terrorist activities both in internal strife and in international settings and a new willingness by
terrorists in the 21st Century to use previously unthinkable means to meet their ends, we must
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