Afterdamp

Afterdamp is the toxic mixture of gases left in a mine following an explosion caused by firedamp, which itself can initiate a much larger explosion of coal dust. It consists of carbon dioxide, carbon monoxide and nitrogen. Hydrogen sulfide, another highly toxic gas, may also be present. However, it is the high content of carbon monoxide which kills by depriving victims of oxygen by combining preferentially with haemoglobin in the blood.