I worked at a quarry that mined cement grade limestone and had a "baking plant: adjoining in order to make anhydrous lime and cement grade lime. They would bake all the water out of it and crush it until it was like confectioners sugar. Then they would "Pipe it" into trucks that were covered and pretty much water tight. (This was in W Virginia where they would get horrible summer showers of 2 to 4" rain in a half hour.
Once, apparently some wags had washed their anyhrdous lime rig and left some water in the water tight bays (the trucks had 4 bays).
The plant loaded them up as a last load until they would quit because of a storm warning. WELL. the water in the one bay reacted with the anhydrous lime and the thing just blew up. It blew the tops off the rig and (they are held on loosely so they would just break off in case of this happening). When the top blew off, it was rainin g and the rain got hold and reacted the other three bays of lime and we had a huge hot steam fire that was mostly the water
We had a drill crew going in the area of the plant to where the quarry was going to be extended . They ducked under the drill table to keep from getting rained on by debris and burning chunks
It sounded like a muffled thunder storm with smoke, steam, and chunks of truck flying and tires rolling about. Fortunately noone was hurt. There is enough time of hissing and smoke going till it goes critical.
Ill bet george ob has some tales to tell about fluid bed incinerators that can "go critical" and start burning from just water on the limestone beds.