Anthrax spores were weaponized by the U.S. in the 1950s and 1960s before the old U.S. offensive program was terminated. Other countries, including the Soviet Union and Iraq, have weaponized this agent or were suspected of doing so. In the fall of 2001, anthrax spores were delivered in the U.S. mail, resulting in 22 cases of confirmed or suspected anthrax disease. Anthrax bacteria are easy to cultivate and spore production is readily induced. Moreover, the spores are highly resistant to sunlight, heat, and disinfectants - properties which create concerns for environmental persistence after an attack. This agent can be produced in either a wet or dried form, stabilized for weaponization by an adversary, and delivered as an aerosol cloud either from a line source such as an aircraft flying upwind of friendly positions, or as a point source from a spray device. Coverage of a large ground area could also be theoretically facilitated by multiple spray bomblets disseminated from a missile warhead at a predetermined height above the ground.
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