Been playing for a while, and this is probably one of the stranger bugs I've seen. Every once in a while a superheated pocket of gas shows up near my coal generator, which I placed in an ice biome. Thankfully, the gas pockets quickly cool down, but if a dupe gets too close they get some nasty burns.
Not entirely sure what causes it, but it has only ever happened near my coal generator in the ice biome; another generator within my base has had no such issues. I also use a liquid cooling system for the generator, though I do not know if that is a factor.