Many households use natural gas, propane or fuel oil heating.
Each product poses a serious health or fire danger if not used and stored properly. A flammable liquid in its liquid state will not burn. It only will ignite when it vaporizes into a gaseous state. All flammable liquids give off vapors that can ignite and burn when an ignition source such as a lighted cigarette or spark is present. To understand the dangers associated with flammable liquids, it is useful to be familiar with the terms used to describe their chemical properties.