Forget the dust collector the drill press is the villain here. To day while
drilling a 8" deep 1" hole with a spade bit at high speed in oak, I had an
explosion. I was about 3 1/2" deep into the hole when with a loud bang and
what appeared to be a flash, dust went all over the shop. Blinded by a layer
of sawdust covering my glasses and with the taste of burned oak (maybe from
oak dust landing in my pipe) I groped for the off switch to the drill press.
In shock I looked at my wood, which was hanging from the drill bit and it
looked fine with out my glasses on, looked fine after I cleaned my glasses
and set down for a minute too. Found some ash and smell of "smoke" in the
hole I was drilling so it must have been a real dust explosion. So dust
explosions do happen but maybe not in dust collectors.