I got blasted in the face when I uncapped a leaking pool filter component that contained a chlorine tablet. It escaped quickly, and besides the awful smell, irritated my nose, eyes, and throat for the rest of the day. So I figured I’d look up a little something about it. I put the cap back on, and took it back off a few minutes later, and didn’t notice the sudden rush of noxious odor that I did the first time. No idea what caused it, but I didn’t like it.