Violates international conventions for chemical weapons, long-term safety data following exposure is sparse but alarming, it’s being used against peaceful people, and this factoid I didn’t know:

“The sale and trade of tear gas worldwide is largely unregulated, and as a result, it's often not clear what chemicals exist in each canister, how toxic these chemicals are, or even whether they've been safety tested beforehand, the researchers explain.”

But in a world where our diabetes drugs are tainted with carcinogens and our ecstasy is mostly meth and caffeine, why did I think there would be any quality control in the chemical weapons industry?