Well this was back when I was surveying, we were doing a topographic survey on a make-up factory and need to climb down into the sewers to get inverts on the pipes leading in and out. It is never pleasant to have to go down in the sewers for obvious reasons. but it turns out this place was dumping chemical into the sewers as well. Well we pull the manhole cover off and immediately get hit with these fumes. we both threw up and refused to continue the day because we were so nauseous. There was this pink fluid with "floaters" going by in the sewer. Anyways we refused to get the measurements siting health and safety reasons. I cannot describe the odour it was so strong it made your eyes water and stomach turn. I find it hard to believe it was legal for them to be dumping chemicals like that but never looked into it.