You might have used expanding foam for a household project, but the chemical used in it can actually be pretty dangerous. The reaction created by combining the chemical is exothermic, which means that it creates a lot of heat. Not to mention, the foam is incredibly flammable, so you definitely don’t want to use it next to a flame. For reasons unbeknownst to us, a crew of firefighters filled a house with explosive foam and then lit it on fire. This short video details the resulting effects from that terrible decision.