I've refused to do many things in the past in my jobs. I once refused to go from being exposed to an air temp of 40 celcius to one of -23 celcius because I didn't fancy ending up ill. I've refused customers service for being very rude to me. When I worked in a restaurant I did have to clean up someone's vomit however if they don't provide the proper resources then I'd refuse it no matter what. Faeces however are out of my durestiction.