Carbon Monoxide Poisoning

Carbon monoxide, with chemical formula CO, is a compound of carbon (C) and oxygen (O₂). It is a colorless, odorless, and tasteless gas that in appropriate amounts is poisonous to human beings and, for that matter, to all warm-blooded animals and many other life forms on Earth. Carbon monoxide is poisonous when, as a result of being inhaled into the lungs, it combines with the blood's hemoglobin, which then prevents the absorption of oxygen into the respiratory system of the body. Carbon monoxide poisoning results when the human body is consistently denied essential oxygen. A person without sufficient oxygen in the blood stream will initially feel dizziness, fatigue, headaches, nausea, and shortness of breath, which will eventually lead to unconsciousness and eventually to asphyxiation and death.

Carbon monoxide is a component of air pollution, both as an intentional or accidental side product, that results from many natural and artificial products, materials, and processes such as gasoline-powered vehicles, furnaces, manufacturing plants, and forest fires. The identification of carbon monoxide poisoning is important to forensic scientists because carbon monoxide can be the primary or secondary cause of such investigations as accidents, homicides, and suicides, or can be used as a deceptive tactic by criminals to hide other causes of crimes. For example, a forensic investigator might examine three unrelated dead bodies inside automobiles within three different closed garages and find (1) one body with carbon monoxide in the blood stream, but without any other suspicious evidence (which indicates a suicide), (2) another body with carbon monoxide in the blood, but with greasy fingers and clothing (which indicates an accidental death), and (3) a third body with blunt injuries to the head and only a small amount of carbon monoxide in the body (which indicates a homicide).

In order to determine the level of carbon monoxide within the blood stream of a deceased person, the accurate measurement of the blood pigment carboxyhemoglobin is required. Carboxyhemoglobin is hemoglobin that is saturated with carbon monoxide. Several detection methods are used for the measurement of carbon monoxide including CO-Oximeter, flame ionization, infrared spectrophotometry, syringe capillary, thermal conductivity, ultraviolet spectrophotometry, and Van Slyke. In ultraviolet spectrophotometry, for example, carbon monoxide is expelled from the blood stream and is then measured when exposed to ultraviolet radiation.