carbon monoxide

an odourless and colourless gas that is highly dangerous when inhaled, leading to carbon monoxide poisoning. In the BLOOD it has a very great affinity for oxygen and converts HAEMOGLOBIN into carboxyhaemoglobin. The tissues of the body are quickly deprived of oxygen because there is no free haemoglobin left to pick it up in the lungs. Carbon monoxide is present in coal gas fumes and vehicle exhaust emissions. The symptoms of poisoning include giddiness, flushing of the skin (because of carboxyhaemoglobin in the blood, which is bright red), nausea, headache, raised respiratory and pulse rate and eventual coma, respiratory failure and death. An affected person must be taken into the fresh air and given oxygen and artifical respiration if required.