The Zamboni story makes me think of rink hazards... though I never thought of the Zamboni catching fire as a high-probability hazard! The rink is an enclosed space, and I sometimes wonder how good the ventilation system is. Every session, my clothes and hair will smell fumy, and though the odors are unpleasant, the more worrisome aspect is whether they are health hazards!
Zamboni fumes - the Zamboni here runs on gas, and I often wonder if there is sufficient ventilation to expel all the fumes!
Leaks - once during ice time early in the morning, the entire rink was smelling of gas... it was scary. It turned out to be a gasoline leak, not from the Zamboni, but from another smaller machine that is used to level the ice next to the boards.
Cigarette smoke - in Singapore, smoking is banned in public buildings, and there are signs put up around the rink to that effect. Still, some public skaters can be obnoxious, and smoke in the toilets. Even the staff find it difficult to stop them!
However, I suppose odors are not the only things we should be concerned about - there are other dangers. Carbon monoxide is odorless but can kill; asbestos doesn't smell but causes mesothelioma. I hope there are sufficient checks in place, and anyway, I really don't think there's any asbestos in buildings in Singapore!