winglet21,
There is one accident coming to my mind. I think it happened in 2001, the refuel coupling of a BA B777 had a bad casting and broke off during refueling at Denver.
AFAIK fuel spilled on the still hot engine, and the fueler was badly burned (I think he died subsequently).
Boeing recommended to inspect the couplings asap (which we did), and we added a regular visual check of the couplings to the maintenance programme (all aircraft I have been involved in so far have such a check in one way or another).
On a more general point of view (no examples at hand!), we have been warned to fill up the tail tanks without paying attention to the aircraft balance - danger of tipping when the rest of the aircraft is almost empty... ;-)
Hope this helps,
J.V.