You only get fire risks when the things they touch are themselves tiny (like dust), so they're unable to absorb and spread the heat.
A similar thing happens when you bake with tinfoil. The foil will be at like 350 F, but you can still touch it basically immediately if you're willing to gamble that nothing with thermal mass is stuck to it where you can't see. It just doesn't have enough thermal mass on its own to burn you, but if there's a good-sized glob of cheese or water or something on the other side you can really be in for a nasty surprise.
Both because you probably shouldn't breathe that shit in, and also magnesium and titanium dust are very enthusiastic about combusting. Everyone knows about magnesium but nobody knows titanium is almost as surly.
Iron dust too. Make sure to keep it away from your pre-lit candles:
Almost ANY small particle in a light-density air suspension (dust cloud) will ignite. Certainly anything that oxidizes is prone to going WHOOF! around flames.
This includes non-dairy creamers, paint spray, insecticide sprays (canned or pumped), and sawdust tossed over a fire.