> HC is a highly regulated toxin, labeled as a “likely carcinogen” and skin irritant by the Environmental Protection Agency. Eye masks and gloves are recommended for people who handle the chemical. Defense Technologies, an imprint of Pennsylvania-based security equipment manufacturer Safariland, markets the HC canisters as “military-style” smokers, even though the U.S. military actually stopped using HC in grenades in the 1990s due to its extreme toxicity.