Methane

Methane (CH₄), colorless, odorless gas; the simplest alkane. It is produced by decomposing organic matter in sewage and in marshes (hence the name marsh gas), and is the “firedamp” of coal mines. Nontoxic but highly flammable, methane when mixed with air, oxygen, or chlorine is explosive. It is the chief constituent of natural gas, occurs in coal gas and water gas, and is produced in petroleum refining. Methane is used as a fuel, for making carbon-black, and for chemical synthesis.