In the early 1950s, the U.S. Army Chemical Corps prepared a series of biological weapons tests in multiple cities across the United States and Canada. These experiments were executed in the mid-1950s through the late 1960s—not before a law was passed to shield private military contractors from all liability for public injury.
As Professor Lisa Martino-Taylor writes, this, in effect: “created a sanction-free military human test zone across North America and blocked legal recourse for victims.”
In short, the Army was ostensibly concerned that the Russians would expose American and Canadian civilians to dangerous agents, so the Army did it themselves in the name of mitigation.
As a part of the tests, the U.S. Army Chemical Corps released zinc cadmium sulfide “from airplanes, rooftops, and moving vehicles in 33 locations, mostly cities and towns, in the United States and Canada.” These cities included St. Louis, MO, Minneapolis, MN, Corpus Christi, TX, Fort Wayne, IN, Biltmore Beach, FL, and Winnepig, MB. The cities were chosen because of their similarity to cities in the USSR.
In St. Louis, the Army’s dispersion methods were insidious. “The Army used motorized blowers atop a low-income housing high-rise, at schools and from the backs of station wagons” to disperse the chemical agent. Local officials were told that the “government was testing a smoke screen that could shield St. Louis from aerial observation in case the Russians attacked.”
Zinc cadmium sulfide itself is a fine powder “that is formed by heating zinc sulfide and cadmium sulfide together under very high temperature so that they fuse…Zinc cadmium sulfide is not a biologic weapon; it was a tracer used by the Army to imitate or simulate the dispersion of biologic weapons.” At the time, the compound was not believed to be dangerous to humans.