We came across this bread burning (a pre-Passover ritual) on 9th Avenue and 45th Street. At first we smelled some plastic burning, but then when we saw what was going on we figured it was just the accelerant used to start the fire. As we watched, however, we noticed several people putting bread wrapped in plastic on the burning pile. Hmmmm. The smell dissipated after a moment, so hopefully those standing close-by weren't too affected.
A very helpful gentleman (who was surprised I knew what matzoh was) explained the ritual as Chametz, the time to clean the house of all leavened bread items. Burning ensures the bread items are truly gone. This Crown Heights website has a very useful explanation as well. A member of Cheveirem was on hand to oversee the safety of this burn, but I don't know, it didn't look too controlled to me. I prefer the burns that are within a container or oven. That said, it seemed to go off without a hitch, and those watching were satisfied that their leavened items were gone for Passover.
I think I'll cook up some matzoh brie.