initiatives that could lead to new counterterrorism technology. It is divided into five sections: how chemicals can be used as weapons; the general capabilities that are needed to help mitigate vulnerabilities; possible approaches to protecting some key systems (such as food distribution); and responding to terrorist attacks, both for first responders and the medical system. Finally, the value of a dual-use strategy for developing counterterrorism technologies that are also economically viable is briefly discussed.


Chemicals continue to be weapons of choice for terrorist attacks. They are readily available and have the potential to inflict significant casualties (from a few to perhaps many thousands in technically possible, if improbable, high-end attacks). And they have characteristics that make them attractive for deployment against an open society: easily concealed, undetectable at a distance, and visually indistinguishable from materials in everyday use. Moreover, the potential for their use causes anxiety. While chemical agents may not have the potential to produce the widespread casualties and destruction that could be caused by epidemic biological agents or nuclear weapons, they are more readily available and can cause significant deaths and injuries and disruption in a local area. Historically, problems of delivery were considered a serious barrier to the use of chemical weapons in warfare, and this has been assumed to be a significant constraint on their use by terrorists. But improvements in the technology for disbursing the agents, the willingness of terrorists to commit suicide, and their focus on killing as many people as possible rather than on targeting a specific person or persons, make the danger of attacks with chemical agents a serious threat.

The most plausible use of chemicals as weapons is in attacking aggregations of people in enclosed spaces (e.g., in subways, airports, and financial centers) in ways that would cause disruption to crucial infrastructure services or render them unusable (closing down transportation or financial systems, for example) and potentially causing widespread loss of confidence in the government’s ability to protect its citizens. Small quantities of chemicals would usually be all that would be needed (for nerve agents, a few hundreds of grams would suffice). Use of a chemical agent in a nonenclosed space, however, is perhaps of less concern, because a toxic cloud would be subject to the vagaries of wind direction and thermal currents, thereby requiring large amounts (many kilograms) of the agent to cause numerous casualties.

Other ways to use chemicals as weapons include attacking people indirectly by contaminating facilities. Nonvolatile chemicals can be very persistent and thus able to taint their targets—and interfere with critical services—for long periods of time.

Harmful agents could also be delivered through existing systems already designed for rapid and widespread distribution, such as the postal system or the

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