Methane

Colorless, odorless, highly flammable gas, the simplest alkane. Methane occurs in natural gas, as firedamp in coal mines, and is produced by decaying vegetation and in the guts of ruminants. Methane is used as a fuel, and as a starting material in manufacture of chemicals. Methane carried into the stratosphere by rising air acts as a greenhouse gas and degrades the ozone layer.