The only thing I have seen like this is when I wrked (briefly) building waterbed frames from wood. The small paint booth we used was full of 2x12 boards, frshly stained and cleared with lacquer. The painter was standing outside the door, lit a cigarette, we hear a whoosh, looked inside where the boards were laid out, they had a flame hovering above the boards. We used the extinguisher and made a mess, powder type, got a real good butt chewing, but with the booth made of wood, it could have been much worse.
"When I was younger, I could remember anything, whether it had happened or not." - Mark Twain