Ammonium calcium carbonate (ACC) is a white, odorless, non-toxic powder that is insoluble in water. It is a common household item and is used in various cleaning agents, fertilizers, and as a food additive. The chemical formula for ACC is NH4CaCO3. It is also known as Composting Baking Soda. It is also called “fireproof sand” because it does not burn or explode easily in a fire.