It has been reported* by the Governments Air Accidents Investigation Branch (AAIB) that the cabin of the plane carrying Emiliano Sala and David Ibbotson was exposed to high levels of carbon monoxide, prior to the fatal plane crash in the English Channel in January 2019.
Dr Chris Morris, Medical Toxicology Centre, Newcastle University, said:
What in a small plane could be a source of carbon monoxide?
“The engine is very likely to be the main source of carbon monoxide (CO) since burning of the fuel will generate CO, particularly if an engine is inefficient as this can produce high levels of CO. How carbon monoxide would get into a cabin though is unclear.
What are the symptoms of carbon monoxide poisoning and how quickly do they tend to come on?
“Typically symptoms are very difficult to spot. They can be very general and non-specific and initially headache and feeling tired and often flu-like symptoms with nausea and tummy upsets. As exposure increases breathing can become difficult. Often these symptoms are overlooked because they are very general and so repeated exposure can occur. This is often the case when faulty heating or cooking appliances in homes are the source of CO.
“How quickly symptoms occur depends on how high the CO levels are in the air and how long the person is exposed. Symptoms can be seen at relatively low, 5-10% carboxy-haemoglobin (HbCO) levels, particularly if the person is a non-smoker (sometimes people who are heavy smokers can have levels of HbCO of 5-10% just because of the cigarettes). Some people, perhaps with heart conditions or existing breathing problems, can show symptoms at lower levels of blood CO where it can increase the problems they already have. Drowsiness can then set in as levels of CO rise and exposure increases. If levels are high enough, often carboxy-haemoglobin above 20%, the chances of damage to the heart and brain due to lack of oxygen are high – CO pushes oxygen off the haemoglobin molecule in blood. At levels of over 30-40% then coma occurs with death due to cardiac arrest. Over 200ppm CO in air would lead to relatively fast symptom onset, within perhaps 15-20 minutes and with prolonged exposure an increasing likelihood of more severe symptoms. Obviously higher levels in the air will lead to quicker onset of symptoms and greater chances of someone having a severe and potentially fatal outcome.
How is carbon monoxide tested for during an autopsy?
“Typically this would be blood carboxy-haemoglobin (HbCO) and looking for levels of over 5-10% that would indicate exposure.”
Dr Chris Morris: “I have been funded by the Gas Safety Trust (www.gassafetytrust.org) which funds education and research projects around carbon monoxide poisoning.”