Historically, gases (other than breathable air) in coal mines in Britain were collectively known as "damps". This comes from the Middle Low German word dampf (meaning "vapour"), and was in use by 1480.
Damps included:
Afterdamp, a mixture of gases (carbon monoxide, carbon dioxide, nitrogen and others) produced following explosions of firedamp or coal dust
Blackdamp, stythe or choke damp, a suffocating mixture of nitrogen and carbon dioxide
Firedamp, any mixture of flammable gases, principally methane
Stinkdamp, usually hydrogen sulfide; toxic and explosive, but easily detectable by the smell
Whitedamp, carbon monoxide, highly dangerous due to being both toxic and explosive but having no warning smell.
The term damp also gives rise to damp sheet, a heavy curtain used to direct air currents and prevent the buildup of dangerous gases.
