Health Complications
During high school, I worked at Walmart. If I had to recall the worst thing that happened during my time there it would be when robbers tried to run out of the store and then the security guards sprayed them with mace, which would flow right back into the store.
There has also been a few elderly people who had to be rushed to the hospital due to respiratory complications. Thanks to the mace, everybody who entered the store would spend their entire time coughing because the mace stayed in the air. The managers were willing to deal with these problems, as long as they did not have to close the store.