Nerve gases biological weapons

The interplay between the chemical and biological properties of the threat agent, on the one hand, and the specific attack scenario, on the other, can influence the lethality of the attack. Table 2-2 shows the relative respiratory toxicities (expressed as the lethal concentration of toxin at which 50 percent of test animals are killed, or LCT50, in milligrams per minute per cubic meter) of a variety of toxic gases compared with chlorine gas, which was used as a chemical weapon in World War I. According to Table 2-2, the nerve agent sarin (GB) has a respiratory toxicity approximately 100 times that of chlorine, while sulfur mustard (HD) is about 7 times more toxic. However, the lethality of an attack... 

University of Pennsylvania, for example, some forty civilian scientists employed by the Institute for Co-operative Research were working exclusively on chemical and biological warfare.61 Whereas the British were devoting most of their energies to the development of new gas masks and protective suits, in the United States much of the work concentrated on the development of new weapons, particularly on problems of how to spread nerve agent more effectively.62... 

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