A gas, which is usually rich in methane (CH4), produced when coal is heated in the absence of air.

gaseous mixture produced by distillation of bituminous coal and used for heating and lighting

Flammable gas derived from coal either naturally in place, or by induced methods of industrial plants and underground gasification.

The fuel gas produced from a high-volatile bituminous coal. Its average composition, by volume, is 50% hydrogen, 30% methane, 8% carbon monoxide, 4% other hydrocarbons, and 8% carbon dioxide, nitrogen and oxygen

Coal gas is a fuel produced by heating coal. It will contain much higher levels of carbon monoxide than would be seen in natural or liquefied petroleum gas.