- Propane is a byproduct of petroleum or natural gas refining. Although it is a gas in its natural state, propane is typically delivered to consumers in a compressed liquid form.
- Propane combusts in a fashion similar to other petroleum products. When there is plenty of oxygen, it burns and leaves behind carbon dioxide and water as waste products. When there is too little oxygen for complete combustion, propane will still burn but will form water and carbon monoxide as waste products. Unlike natural gas, propane is actually heavier than air; when released into the atmosphere, it readily sinks to the ground.
- The application of propane that most people are familiar with is as a fuel for gas cooking. An outmoded refrigerator design that is still sometimes encountered called a gas absorption refrigerator uses propane as a coolant, and it is being looked at in modern times as an environmentally friendly cooling substance. It is also used by industries that require portable heat sources or those who operate furnaces, such as brick kilns. There are also an increasing number of vehicles on the roads that run on propane, called "autogas" when used in that way.
