ETHANE is a mnemonic indicating a protocol used by emergency services to report situations which they may be faced with, especially as it relates to major incidents, where it may be used as part of their emergency action principles. An alternative mnemonic METHANE adds an additional prompt "Major Incident Declared?" to ensure consideration is given to if the response may challenge the available resources and so necessitate initiating contingency plan measures.

Ethane ( or ) is an organic chemical compound with chemical formula C₂H₆. At standard temperature and pressure, ethane is a colorless, odorless gas. Ethane is isolated on an industrial scale from natural gas, and as a byproduct of petroleum refining. Its chief use is as petrochemical feedstock for ethylene production.

Methane ( or ) is a chemical compound with the chemical formula  (one atom of carbon and four atoms of hydrogen). It is the simplest alkane and the main component of natural gas. The relative abundance of methane on Earth makes it an attractive fuel, though capturing and storing it poses challenges due to its gaseous state found at standard conditions for temperature and pressure.