food and water supply networks (the latter two are discussed in more detail later in this chapter). The anthrax attacks in the fall of 2001 demonstrated the effectiveness of using such systems both to harm people and disrupt an important service. A concerted attack from multiple locations could have resulted in widespread contamination of many of the automated centers where mail is sorted and distributed, resulting in large numbers of infected mail workers and recipients—and possibly even shutting down the U.S. Postal Service. Countless businesses could also have been contaminated. Other mass-distribution systems—currency, newspapers, and junk mail, for example—might also be used to expose large numbers of people to the effects of infectious or toxic substances or to interfere with the functioning of society.

A wide variety of chemicals—including many in common use—could be used as weapons. There are three major classes of such chemicals:

  1. Chemical weapons (CW), developed by states for military use; 2

  2. Toxic industrial chemicals that are produced, transported, and stored in large quantities in the civil economy; and

  3. Explosives and highly combustible materials.

These three classes of chemicals are discussed below.

Military Chemical Weapons

Chemical weapons were first used in World War I and drew on existing industrial chemicals (chlorine, phosgene). In the period after World War II, a number of countries (especially the United States and the Soviet Union) continued to develop chemicals specifically designed as weapons: The most important of these are the so-called nerve agents and blister agents (e.g., sarin and mustard gases). A number of such chemicals have been produced, and they can be delivered in a variety of ways, including sprays, rockets, mortar shells, mines, and other explosive devices. Several of these chemicals were designed to have very high toxicities (Table 4.1).

Chemical weapons were not used in World War II, and the United States discontinued its CW programs in the 1960s, at least partly on the grounds that CW were not militarily effective. The Soviet Union reached a different conclusion and continued, up to the 1990s, to develop chemical weapons for military use. In fact, chemical weapons appeared to be a standard part of Soviet operational doctrine, with special utility in slowing and blunting offensive operations,


Some biological and radioactive agents are occasionally considered in this chapter along with chemical agents because the responses to attacks with them would be similar. Such biological agents include botulinum toxin, staph enterotoxin, and ricin. Radioactive agents, in this context, mean dispersible radioactive materials (as distinct from nuclear weapons); they are discussed in Chapter 2.

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