Most of us who have been in the military have either heard of or used firefighting foam. It is commonly known as either Aqueous Film Forming Foam (AFFF) or perfluoroalkyl and polyfluoroalkyl substances (PFAS). While you may remember the odor of AFFF and know that it will put out burning jet fuel, you may not know how hazardous it is in its own right. In fact, it's so bad that more than 180 countries have banned its production and use except in emergencies. Read more on Military.com.