CS is one of two types of tear gas; the other being CN. Nobody was killed with CS, though they might wish they were.
CN irritates your eyes and that’s about all. I found it annoying, nothing more.
CS, on the other hand, irritates all of your mucus membranes including nose, throat and lungs, and all of it hurts.
These things I learned by tear-gassing THOUSANDS as a U.S. Air Force gas mask instructor. And if the students gave me any crap that day, or wore too much brass, then I might have added an extra CS capsule, or three, to the burner. Purely by accident, of course.
Yes CS is very irritating. Just for laughs, there’s a tree right outside the exit of the Fort Leonard Wood gas chamber. I couldn’t get out of that chamber fast enough. I managed not to hit the tree though.