I was shoveling out some of the wood chips that have been in a pile for, oh, about three years or thereabouts, and smoke came out from the black stuff about a foot deep into the four foot high pile.
I touched it with my hand and it was only warm. Not hot. Where did the smoke come from?
It was consistent. I'd shovel off a foot or two until I get to the black stuff and I'd see smoke. It wasn't dust as it was wet and gunky a foot under.
Then I'd touch the wet black gunk with my hand, and it was only warm. Not hot.
Ever see smoke in compost but it's not hot to the touch?