Missouri’s Republican senator is asking the secretary of the Army to investigate reports that the military may have conducted secret Cold War-experiments on his unsuspecting constituents.

A St. Louis TV station reported this week that zinc cadmium sulfide was sprayed on thousands of residents, with the greatest concentration on a low-income housing complex, but the reporters were not able to substantiate whether the Army added a radioactive element to the compound.

“I am deeply troubled in light of recent reports that the U.S. Army may have been involved in exposing thousands of unsuspecting Missourians to a chemical called zinc cadmium sulfide during the Cold War. I’m particularly concerned by allegations that these tests of zinc cadmium sulfide throughout the 1950s and 1960s might have contained a radioactive component that went undisclosed in initial reports,” Sen. Roy Blunt (R-Mo.) wrote to Army Secretary John McHugh today.

“The idea that thousands of Missourians were unwillingly exposed to harmful materials in order to determine their health effects is absolutely shocking. It should come as no surprise that these individuals and their families are demanding answers of government officials.”

Blunt asked McHugh to dig back decades into the records and turn over answers regarding which areas were subjected to the spraying and about the health effects of exposure.