My daughter had a box of foil pack Bromo-seltzer in her medicine cabinet. Last night she heard a loud pop and something falling on the floor. On investigation, she found the exploded box on the floor with two totally exploded foil packs and the remaining 4 packages very puffed up. Looks like all six packs reacted at the same time. No excessive heat or moisture involved. I have a chemistry back-ground and would like to know what caused this reactive chemical incident. Cannot find any reference to similar incidents on the internet. Could this happen with the bottle type packaging? (small bomb?)