Chemical warfare agents are among the easiest WMD to produce. The toxicity of chemical agents falls generally between that of the more deadly biological agents and that of conventional weapons. The earliest chemical agents, first used in World War I, were far less sophisticated and far less lethal than those developed in subsequent decades. Proliferating nations have tended to first produce blister agents and, as their technologies advance, to develop the more lethal nerve agents.
Many CW agents, particularly choking, blood, and blister agents, are relatively easy to produce. Some of their technologies are more than 80 years old, making them accessible by virtually any Third World country and many terrorist groups. Newer agents, particularly nerve agents, are somewhat more difficult to produce. However, much of the technology to produce these agents is widely available in the public domain and, as demonstrated by the Aum Shinrikyo in Japan, these agents can be produced by a determined terrorist group.
Production of CW agents is similar to that of legitimate commercial compounds. Both involve use of standard chemical process equipment. Some of the more sophisticated equipment is distinctive enough to warrant special consideration, and some of this equipment is controlled by the Australia Group. In particular, equipment that is exceptionally resistant to corrosion has important applications for CW because of the highly corrosive compounds encountered in CW agent production.
Development of a dispersal device is somewhat more technologically complex than the production of chemical agents. Many conventional munitions, such as bombs, artillery shells, grenades, and mines, can be modified to deliver chemical agents. A spray tank, commercially available for dissemination of agricultural chemicals from aircraft, can be used to disseminate chemical agents. Similarly, ground-based aerosol generators used to disseminate pesticides can be used for CW purposes.
Chemical warfare (CW) can be considered the military use of toxic substances such that the chemical effects of these substances on exposed personnel result in incapacitation or death. It is the impact of chemical effects instead of physical effects (such as blast and heat) that distinguishes chemical weapons from conventional weapons, even though both contain chemicals. In many cases in the Third World, there can be considerable confusion as to what is a chemical weapon and what is not. Some countries consider smoke, flame, incendiary, or riot control weapons to be chemical weapons and label them as such. In addition, conventional weapons can inflict casualties resembling those caused by chemical weapons.