Whitedamp

A toxic mixture of gases formed by coal burning slowly in a confined space, whose dangerous constituent is carbon monoxide — colourless, odourless and tasteless, and lethal even at very low concentration.

Historical usage

The word is recorded in English from around the 1810s-1820s, as Britain's coal boom and a run of serious colliery disasters brought early parliamentary safety inquiries; by the 1830s it appears regularly in official colliery-safety reports, as one of the named 'damp' family alongside firedamp, blackdamp/chokedamp and afterdamp (all covered on this site's own term pages).

How it worked

Coal exposed to air in a mine can begin to smoulder and burn slowly, especially where old workings or a fire are starved of enough oxygen for full combustion; this incomplete burning produces carbon monoxide rather than the harmless carbon dioxide full combustion would give. As little as 0.1% carbon monoxide in the air can kill a person within minutes.

Why it was used

Because whitedamp gives no warning to human senses at all, miners relied on canaries, far more sensitive to carbon monoxide than people, carried into suspect workings as a living early-warning system — a bird overcome or falling from its perch told miners to withdraw immediately, well before the gas became dangerous to them.

Risks & limitations

Whitedamp's total undetectability by taste, smell or sight made it one of the most insidious mine gases, since a miner could be overcome with no warning whatsoever beyond an animal detector's reaction.

Regional variation

Whitedamp is closely related to, and often overlaps with, afterdamp — the gas mixture left behind after a mine fire or explosion — since carbon monoxide is a major component of both.

Sources

1. (primary) Definition of white damp — Mindat
2. (secondary) The Most Dangerous Gases In Mining — Chart Industries
3. (secondary) Whitedamp — Wikipedia

Record created: 21 August 2026 · Last researched: 21 August 2026