I do find it scary that Apple has somewhat of a history of making stuff that catches fire...
I'm not sure about a history of fire, but there have been a series of battery problems, one of which is overheating. THIS however is not a battery problem from what I can see.
Ever since the iBook years ago, people have had super-heated battery complains. All events were not universal, but some people got badly made batteries or had charging problems that would heat up the device. Not sure if any have actually caught fire in those heat events.