Among animals, making light (outside their body) seems to be an occupation engaged in only by man.  The photo above is of a thorium mantle incandescing  white hot. Wikipedia has more info.

Atom bomb, anyone?  (about a million mantles and you could make one)

Light your cigarette in the invisible heat above the glass chimney?  Lean over the chimney too far and ignite your hair too!

A little radium in your lungs? Where's that little piece of missing "ceramic" weave?

The perception of the homey and comfortable atmosphere surrounding a gas mantle lamp  probably is a miss-perception.  

 But in the big picture there are many "elements" and chemicals coming into contact with us of which we are entirely unaware.