Warehouse already went boom. Nothing left to burn.

I also know that most explosives can be safely burned, I grew up in a mining town. Most explosives require an actual explosion to set off, thus the use of blasting caps and detonation charges (Or, my personal favorite, DETCORD!). But most folks wouldn't know that.
I remember an old trick I learned about from WWII vets that were in Africa was that they shaved explosives to make a fire when wood was scarce in the area they were around, and they were allowed to have a fire in the first place.