When I was working my way through school I worked at a paper mill night shift. I was doing fill in for a person un jamming a hog fuel stump and junk wood grinder that they used to fuel a boiler. I stood above it just to the side of the wood feeding into it and used a long pole to un jamb the wood when it got hung up. After about a week I asked when the guy was coming back from vacation. The boss shook his head "no". I asked where he went and the guy pointed down into the grinder. No safety harnesses or anything in those days. Same as when I worked bridge construction, walking the steel beams with no safety what so ever.