Natural gas is colorless, and odorless. In its purest form (such as the natural gas that is delivered to your home), natural gas is almost pure methane. Natural gas can also contain ethane, propane, butane, and pentane.

Methane is a molecule made up of one carbon atom and four hydrogen atoms, and is referred to as CH4. Natural gas is considered “dry” when it is almost pure methane, having had most of the other commonly associated hydrocarbons removed. When other hydrocarbons are present, the natural gas is considered “wet.”