Carbon Monoxide Poisoning

If we are carbon based how come we can be poisoned by carbon monoxide? Can we be poisoned by carbon dioxide?

A CO poisoning cartoon for you:

Carbon dioxide is harmless.

Lots of carbon compounds are deadly.

Specifically, carbon monoxide is absorbed by the red blood cells instead of oxygen. However, CO can’t be absorbed by the rest of the cells or “unabsorbed” when the red blood cell gets back to the lungs. Essentially, the person asphyxiates since oxygen can’t get distributed to the rest of the body.

Hey beatle - no fair getting in front of me!

Carbon dioxide will not poison you, per se,
but it will asphyxiate you.

Hey, I can play that game: If our bodies are 9X% water, how come we can drown in the stuff?

Ray (Logic for all occasions.)


Just about every naturally occurring poison and venom contains carbon.

What you really need to do is to take a class in chemistry. You will find out that a compound can have drastically different properties not only by changing one element in the molecule, but also by rearranging the elements in the molecule.

Also, you need a class in biology. Pure oxygen will also eventually kill us. You’ll need to learn the body’s chemical reactions to understand why.


“Too much of anything, even love, is not necessarily a good thing, Lieutenant.”

(Or something very close)

Captain James Tiberius Kirk (obviously thinking of the fact that even water in too large an amount causes death)

CO2 can cause more than asphyxiation. Recalling from the movie Apollo 13 (which is confirmed by nasas historical docs on apollo 13) The CO2 levels got dangerously high even though there was adequate oxygen.
Of course this was something like 9% concentation, and CO is considered a health risk at 50ppm or 0.005%.

CO binds to the same receptors on the hemoglobin molecule as O2. Once attached, they have a much greater affinity to the hemoglobin than the O2 does. Eventually, if you get enough CO stuck onto your O2 receptors, you’re a dead duck. The treatment of CO poisoning is hyperbaric O2.

CO2 is a product of you bodies metabolism. It exists in very minute amounts in the atmosphere. Having healthy lungs equates to being able to exhale it as fast as it is produced. Breathing CO2 has the same effect as holding your breath. The pH of your blood lowers and all the chemical reactions that make life possible get screwed up and you die.

You go, Nicky-Boy. Many is the day that I had to suffer while working IN and UNDER the blanket of dry ice…subliming away madly. It doesn’t suffocate, but it is heavier than air, and so…presses the air DOWN and away from average head height.
End result? A terrible headache, dizziness, inability to focus. Sounds like…hypoxia, huh? Damned theatre people…


The ones who told me that CO binds to the hemaglobin and blocks O2 absorption answered my question. I guess in the pursuit of brevity I was too vague. What I was really wondering is why we can’t break down CO to usable components. Is just carbon bad for us?

No, as was remarked, you cannot make any assumptions about CO from either C or O. We can’t handle CO because (from an evolutionary viewpoint) it’s rare in nature, so we never evolved a mechanism to handle it.

John W. Kennedy
“Compact is becoming contract; man only earns and pays.”
– Charles Williams