Originally Posted by
PDR1
CO poisoning produces permanent damage to red blood cells - it's a signature which remains and can be identified even in a long-deceased body and it gives fairly precise values of the scale. CO poisoning is not just a matter of lack of oxygen (as happens with CO2) - it is actually a poisonous gas. CO "locks" the haemoglobin in the blood such that it can't take oxygen even when it's present. If you suffer CO poisoning beyond a certain level even getting you away from the CO and giving you 100% oxygen via a mask won't save you - you will die unless you are given a rapid and massive transfusion of red blood cells (which is rarely possible).
So the detection of CO poisoning in "a body that had been under seawater for so many days" is not in any way remarkable or strange.
PDR
Thanks PDR. Some googling on my part comes up with similar explanations. Apparently CO suicides often change their minds, but then find its too late to escape from the stuff.
SND