How does carbon monoxide cause soda cans to explode?

[russ_watters]

You need much less CO than CO2.

And less is produced.

This was already pointed out. I was reiterating the point that even though CO kills at a much lower concentration, if much more CO2 is produced, it could be CO2 that kills you.

In some scenarios maybe. But here the victim was found in the house, not in the garage.

Right: My conclusion applies to my scenario.

 

[A.T.]

I was reiterating the point that even though CO kills at a much lower concentration, if much more CO2 is produced, it could be CO2 that kills you.

Other difference are (I think):
- For CO2 risk it's the CO2 to O2 ratio in the air that is crucial, rather than the CO2 concentration on its own.
- In case of CO2 you recover quicker, once you get air with high O2 to CO2 ratio. But CO binds to your hemoglobin, and blocks O2 delivery for a while, even when enough O2 is coming into your lungs.

 

[gmalcolm77]

I thought that the emission control would turn the engine off before there was more than a safe level in the garage. Was it just an urban legend that it is now difficult to kill yourself with a tube from the exhaust pipe? Perhaps I am just gullible.
No, I don't think it is that the engine turns off. The catalytic converter is supposed to reduce greenhouse emissions, thus, lower CO2 and co. which are gasses that will kill.

 

[jbriggs444]

The catalytic converter is supposed to reduce greenhouse emissions, thus, lower CO2 and co. which are gasses that will kill.

A catalytic converter does not reduce CO2. It produces CO2 as a result of completing the oxidation of CO and unburned hydrocarbons.

 

[Jehannum]

And for that reason, [CO₂] is used to euthanize animals.

Animals can sense excess CO₂, so this method of euthanasia may not be as painless as one may think. Nitrogen would be better as an asphyxiant since it does not produce the same sensation of suffocation. This lack of sensation causation makes N₂ dangerous (e.g. when working with pressurised nitrogen in confined spaces you may not realize you're being asphyxiated), and is the reason that nitrogen is being considered as a "humane" replacement for lethal injection in the US.

 

[James Demers]

Recent event where dry ice, being transported in a car, killed one of the passengers:
https://www.usatoday.com/story/news...ton-death-dippin-dots-delivery-car/870007002/

CO kills by blocking the ability of hemoglobin to carry oxygen - with the brain deprived of oxygen, you pass out quickly, and then you die, even if there's plenty of oxygen in your lungs. You'll never know what hit you, which is why we have CO detectors.
CO2 is different: your blood normally carries CO2 from the body to your lungs, where it gets exhaled. It's an equilibrium process, and too much CO2 in the air you inhale prevents the exchange, and can even drive the exchange in the wrong direction. Too much CO2 in your blood (hypercapnia) causes all sorts of things to go wrong, and it can be a very unpleasant way to die. https://en.wikipedia.org/wiki/Hypercapnia When CO2 is used for euthanasia, it's not being used as a toxic agent, but as a (relatively) inert gas: the animal passes out from lack of oxygen before hypercapnia can set in. It's 'ideal' from a veterinarian's point of view because it's safe, cheap, and free of regulations and paperwork. (Nitrogen requires high pressure hardware and a mess of workplace safety regulations.)

I've tried breathing pure CO2 in the lab - it's irritating, probably due to being a mild acid when it dissolves, and it triggers a reflexive cough. Continued breathing of pure CO2, I think, would be pretty uncomfortable, for however long it takes to pass out for lack of oxygen.

 

[Danny Sleator]

Recent event where dry ice, being transported in a car, killed one of the passengers:
https://www.usatoday.com/story/news...ton-death-dippin-dots-delivery-car/870007002/

CO kills by blocking the ability of hemoglobin to carry oxygen - with the brain deprived of oxygen, you pass out quickly, and then you die, even if there's plenty of oxygen in your lungs. You'll never know what hit you, which is why we have CO detectors.
CO2 is different: your blood normally carries CO2 from the body to your lungs, where it gets exhaled. It's an equilibrium process, and too much CO2 in the air you inhale prevents the exchange, and can even drive the exchange in the wrong direction. Too much CO2 in your blood (hypercapnia) causes all sorts of things to go wrong, and it can be a very unpleasant way to die. https://en.wikipedia.org/wiki/Hypercapnia When CO2 is used for euthanasia, it's not being used as a toxic agent, but as a (relatively) inert gas: the animal passes out from lack of oxygen before hypercapnia can set in. It's 'ideal' from a veterinarian's point of view because it's safe, cheap, and free of regulations and paperwork. (Nitrogen requires high pressure hardware and a mess of workplace safety regulations.)

I've tried breathing pure CO2 in the lab - it's irritating, probably due to being a mild acid when it dissolves, and it triggers a reflexive cough. Continued breathing of pure CO2, I think, would be pretty uncomfortable, for however long it takes to pass out for lack of oxygen.

You're missing a very very important point. Hold your breath. You'll notice that after a while you will begin to develop a feeling of urgency to breathe. This occurs because your lungs detect the presence of high levels of CO2 inside of them. This is how your body tells your brain "BREATHE! YOU'RE GOING TO DIE! DO IT NOW!" This is the evolutionary mechanism that has developed to keep you breathing.

That's why death by CO2 is so vastly much rarer than death by CO. Because when you're being poisoned by CO2 YOU KNOW IT, and you know you have to find fresh air in order to breathe. It also explains your observation of how unpleasant it is to be breathing CO2.

It is NOT IDEAL for use by veterinarians because the IT'S TORTURE! Its like being waterboarded. And it is not, in general, recommended for euthanasia because of how painful it is to die that way. https://www.ncbi.nlm.nih.gov/pubmed/15901358

 

[A.T.]

...lungs detect the presence of high levels of CO2 inside of them.

What sensory mechanism in the lungs does that? Or did you mean that of high levels of CO2 in the blood trigger that reflex?

 

[James Demers]

Find the outlier:
https://uploads.disquscdn.com/image...86d986540536df786ac7c0136878a8200ff0a030f.jpgLack of O2 knocks the animals out before the CO2 level in the blood can register, which as you note takes a while to kick in. The distress, from my experience, is due to carbonic acid, which is definitely irritating to the lungs. How "torturous" thirty seconds of this would be is a matter of individual judgement, but it seems to be acceptable to the people who do it. (Last I checked, veterinarians tend to care about animals and animal welfare.) It's less than perfect, but they make the tradeoff for simplicity and safety, which is the only point I was making.