Most people have no idea how many dust explosions happen in the world. Grain dust in grain silos and elevators. Google the Diamond Sugar plant explosion. And, there is a reason they say not to throw flour on a kitchen fire. If it contains carbon, is finely ground and dry, a high concentration floating in air containing a normal oxygen content can be ignited with a spark as easily as coal dust. Sulfide rock dust is also highly flammable. But, that goes without saying. 

Wet 'er down!!!