My wife manages a mobile home park and one of the tenants had a tripping breaker. When he reset it it "exploded" and he got burns on his hand and face. Old trailer with alum. wire. A reminder to be careful out there. Rod

a link to the artical in the paper. Rod http://www.signonsandiego.com/uniontrib/20050325/news_2m25briefs.html

Livetoride,
It sounds like there must have been a fair sort of a Short-circuit on the breaker to cause it to explode.
Care needs to be taken with resetting any breaker, that has previously tripped.
Finding out what tripped it in the first place, before resetting it, often saves nasty surpises.