Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other gases such as propane. It sometimes contains a small percentage of non hydrocarbon gases such as carbon dioxide, nitrogen, hydrogen sulfide, or helium. It is formed when decomposing organic matter is exposed to intense heat and pressure under the surface of the Earth over millions of years.
Natural gas is often burned as a fuel for heating and generating electricity and are among the cleanest and least destructive energy sources to the planet. However, the gas systems and its distribution networks can be unreliable and potentially dangerous during catastrophes and disasters.