I rolled up on a fight involving about 6 guys one night. I disengaged the slide safety on my OC, but then in the ensuing mayhem, never used it. I forgot to reset it.
At the end-of-shift, I stashed my duty belt in the trunk of my car because my wife and I were going to the range the next day. On the way there, an ammo box shifted and depressed the OC button and the entire cannister discharged.
My wife started coughing and gagging and her eyes started burning. I was driving along, saying, "I recognize that smell" but I couldn't place it. Finally, it clicked and I stopped. When I opened the trunk, everything was coated with OC. It took her hours to feel better. Anytime it comes up, she gets upset all over again. I cleaned out the trunk later that day, but depending on the weather, I would still get a whiff of it from time to time for a few years later.
I've been sprayed so many times as an OC instructor, it doesn't bother me all that much. My eyes still close, I still cough, my skin still burns, but I can fight through it fairly well. For a while, I was testing new brands we were considering using at the PD. I probably took about 15 to 20 hits. I was so glad when I finally just decided on a particular brand.