As of last Thursday (6/28/2007) all that is being 'said' is:
Guy was able to speak at Burn Unit, wife was at his side. 30-40% 2nd & 3rd degree burns on face, neck and upper body areas. No info on anything other than burns.
As to the cause...nothing official available.
Speculation and opinions (unofficial) is that the switch was in the 'ON' position as the fuses where being installed, and 'something' went to ground on the dead front.
The above paragraph is the 'buzz' going around from various unofficial sources, there is NO official comment on this accident.
Stay safe.
John