The powder scattering was part of Operation Large Area Coverage (LAC), a series of tests the Army says were designed to assess the threat of biological attacks by simulating the airborne dispersion of germs. The experiments exposed large swathes of the United States, and parts of Mexico and Canada, to flurries of a synthesized chemical called zinc cadmium sulfide.

Martino-Taylor, a professor at St. Louis Community College-Meramec, admits she has no direct proof radioactive material was released in St. Louis, but her report on the chemical tests compelled both of Missouri's U.S. senators to send letters to Army Secretary John McHugh demanding information, according to the Associated Press.

 

Her study examines organizational connections between scientists working on the zinc-cadmium-sulfide tests in St. Louis and researchers who, at around the same time, were engaged in human radiation experiments and releases of radioactive material into the environment that have been proven. (Many established human radiation experiments in the United States are detailed in the 1995 report of Bill Clinton's Advisory Committee on Human Radiation Experiments.)