Actually, the Minneapolis foggings were part of an ambitious series of experiments meant to find out how clouds of anthrax and other airborne diseases would behave over Russian cities. … Zinc cadmium sulfide dust was the simulant for anthrax, useful because it was fluorescent under ultraviolet light, and Minneapolis was the simulant for Kiev, in Soviet Russia.

Nicholson Baker, Baseless- My Search for Sec…, loc. 268