Occupational Elf

Today I had two hours of welcome-to-your-new-workplace occupational health and safety indoctrination. There was even a film, to illustrate the importance of sitting with the top of my computer screen at a level with my eyebrows. I feel ever so much more healthy and safe as a result of my learnings in occupational health and safety, but I'm wondering where the "occupational" bit fits in. I've barely had a chance to even sniff the grindstone, so busy have I been learning that if my building spontaneously combusts I should go outside. As the OH&S lecture neared the close of its second hour, it became clear that the lecture theatre was full of persons, like me, wondering when they would fit seventeen hours of work into the day. Thus, when our instructor called for questions, and met with a peeved silence, I resisted the urge to ask the question that had been singlehandedly keeping me conscious for the past thirty minutes, viz., who, what, why is an "occupational hygienist"? Every good OH&S department should have one, of course, but what exactly do they do? Are they responsible for the dispersal of campus sewerage? The disinfecting of rubbish bins? Do they advise individual staff on nail brushing and soap use? Will the occupational hygienist take one look behind my ears and declare me a threat to occupational health and safety? Do school children get career counselled into occupational hygienism? I want answers, and there's no way I'm taking my scungy fingernails to OH&S to get them.