Arrie... Arrie... your friend shouldn't play with fire if he doesn't know what he's doing (I assume it's a he).
He knows what he is doing, but hypothetically he might want to make a big batch of 50/50 to make smoke grenades, in order to re-live his childhood when he and his friends went down to the grocery store and bought saltpeter and sugar and mixed it and then filled an empty bottle, lit it and watched in awe the giant cloud of smoke. Again, hypothetically, that big batch might accidentally catch fire and engulf two/three blocks in thick smoke. If that where to happen, how would you stop it?
Never mind.
