Damp (mining)

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:

* After damp, a mixture of gases (carbon monoxide, carbon dioxide, nitrogen and others) produced following explosions of firedamp or coal dust
* Black damp, stythe or choke damp, a suffocating mixture of nitrogen and carbon dioxide
* Fire damp, any mixture of flammable gases, principally methane
* Stink damp, usually hydrogen sulfide; toxic and explosive, but easily detectable by the smell
* White damp, carbon monoxide, highly dangerous due to being both toxic and explosive

The term damp also gives rise to damp sheet, a heavy curtain used to direct air currents and prevent the buildup of dangerous gases.

From http://en.wikipedia.org/