How does carbon monoxide cause soda cans to explode?

[DBBPhysics]

I just read an article about the hazards of the keyless feature on new cars (https://www.nytimes.com/2018/05/13/...less-cars-and-their-carbon-monoxide-toll.html). Apparently, it can be easy to not know a car is still running in the garage even though one might think that the car must be not running because the key fob is on the person after going into the house. Therefore, there have been deaths due to carbon monoxide poisoning. One thing noted in that article was that soda cans can explode in the presence of carbon monoxide. I don't understand what physics are at hand that would cause that to occur. For the cans to explode, the pressure inside must be larger than the pressure outside the cans. If the pressure outside the cans is lower than normal, would not the garage implode before the cans explode or at least cause air to infiltrate the garage instead of imploding? Can anyone explain it to me?

Thanks

 

[Drakkith]

Hmmm. I've never heard of this before, and a quick google search turned up nothing. I'd remain skeptical for now.

 

[russ_watters]

I would think it was the heat, not the carbon monoxide. Having a car idling in your garage is the equivalent of about 10 electric space heaters.

 

[CWatters]

I note that was attributed to a victims son.

I can't think of a reason why C0 would cause soda cans to explore. Heat perhaps?

 

[sophiecentaur]

I would think it was the heat, not the carbon monoxide. Having a car idling in your garage is the equivalent of about 10 electric space heaters.

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.

 

[Herman Trivilino]

If the pressure outside the cans is lower than normal, would not the garage implode before the cans explode or at least cause air to infiltrate the garage instead of imploding?

Air would infiltrate, enough to prevent an implosion.

Look at the photograph of the exploded cans of Pepsi. They all failed at the seam around the lid. Moreover, the Pepsi cans are staked atop other cans that appear to be identical except they contain some other kind of beverage. I can't tell from the little bit of can that shows in the photo, but they appear to cans of soda also. Perhaps Mountain Dew? Can anyone tell?

I believe Mountain Dew and Pepsi are made by the same company.

My first guess is that there's a seal around the lid of the Pepsi cans that fails in the presence of carbon monoxide.

Anyway, everyone should have a CO detector in their home. I have two, one is a dedicated CO detector and the other is part of a smoke detector. I am now seriously thinking about putting one in my garage, too.

 

[DBBPhysics]

I note that was attributed to a victims son.

Yes, maybe that is the answer: the son made the comment that the cans exploded because of the carbon monoxide rather than an expert making that claim and the writer for the NYT did not check it out his statement (I'm shocked!...).

 

[russ_watters]

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.

Must be an urban legend. I can't imagine why - or even how - a car would be programmed to do that.
[edit]
I'm wondering though if it is a myth that it is CO that kills you in the common suicide scenario. CO2 seems more likely to me.

 

[russ_watters]

Look at the photograph of the exploded cans of Pepsi. They all failed at the seam around the lid...

My first guess is that there's a seal around the lid of the Pepsi cans that fails in the presence of carbon monoxide.

Well:
1. Google tells me CO is not corrosive at low concentrations and atmospheric pressure.
2. As far as I know, the seal is mechanical: it is crimped.
3. You can see the kids are bulged from being under excessive pressure.

Anyway, everyone should have a CO detector in their home.

Agreed.

 

[Drakkith]

2. As far as I know, the seal is mechanical: it is crimped.

There is a sealing compound added to the crimped seal to keep it airtight, but I can't imagine it would cause a can to explode if degraded.

 

[Danny Sleator]

I read the article, then came here because I googled that same question. I have a solution to the mystery of the exploded cans.

A father was living in the house. He was the one who was killed by the CO. The son inspected the house after the incident. He found the exploded soda cans.

My theory is that those cans had exploded before the CO incident. Perhaps the father had left them in a hot car and they exploded. He just took them and put them in the garage. Later (perhaps years later) the father was killed by CO. So there is no connection between the exploded pepsi cans and CO. Mystery solved.

 

[russ_watters]

I have a solution to the mystery of the exploded cans.

A father was living in the house. He was the one who was killed by the CO. The son inspected the house after the incident. He found the exploded soda cans.

My theory is that those cans had exploded before the CO incident. Perhaps the father had left them in a hot car and they exploded. He just took them and put them in the garage. Later (perhaps years later) the father was killed by CO. So there is no connection between the exploded pepsi cans and CO. Mystery solved.

Seems unnecessarily convoluted compared to my simpler explanation, to me.

 

[Herman Trivilino]

There is a sealing compound added to the crimped seal to keep it airtight, but I can't imagine it would cause a can to explode if degraded.

I wouldn't call what I saw in that photo an explosion. If anything, it looks like a safety mechanism was activated to prevent an explosion.

 

[Herman Trivilino]

I would think it was the heat, not the carbon monoxide.

Is what we see in that photo consistent with that explanation? Only the Pepsi cans failed, and all the Pepsi cans failed. And all at the same place, the seam around the lid.

 

[CWatters]

Perhaps the cans froze over winter and ice pushed out the tops?

 

[nonphysicist]

Not a physicist, but it looks like the cans below Pepsi are YooHoo, not carbonated. In the NYT picture, there looks like Pepsi residue on the lids of the cans below- especially on the right (but not as much as one would expect) and little bits of spatter on the package of what looks like paper towels to the left, and plastic sheeting on the right. Heat would make sense, think of all of the heat energy in a gallon of gas, let alone however many were burned while the car was idling. Truly sad, however.

 

[Drakkith]

Is what we see in that photo consistent with that explanation? Only the Pepsi cans failed, and all the Pepsi cans failed. And all at the same place, the seam around the lid.

Am I missing a photo? I don't see a picture that includes soda cans anywhere in the article.

 

[russ_watters]

Is what we see in that photo consistent with that explanation? Only the Pepsi cans failed, and all the Pepsi cans failed. And all at the same place, the seam around the lid.

The Pepsi cans are higher up than the other cans, and stratification is pretty substantial in a situation like this. And there are other potential factors: they may not be identically constructed, the liquids may not be identical and the ones on the bottom may be sitting on something that could conduct heat away.

Also, if you look closely at the pictures you can see the tops themselves are bent outward, indicating they were substantially pressurized before the crimp let go.

...although the article appears to have been edited to remove the photo.

 

[Woolman]

Am I missing a photo? I don't see a picture that includes soda cans anywhere in the article.

The article has been revised to remove the bits about the cans. See https://imgur.com/a/d9w7XWa

 

[russ_watters]

Am I missing a photo? I don't see a picture that includes soda cans anywhere in the article.

It appears to have been removed -- possibly they realized the error in the explanation. I'll see if I can find a copy in my cache or on my cell phone to upload.

 

[russ_watters]

The article has been revised to remove the bits about the cans. See https://imgur.com/a/d9w7XWa

Thanks!

 

[russ_watters]

To me, the key that says elevated internal pressure is the fact that all the tops that failed popped from concave to convex, indicating higher than normal internal pressure before the seal/crimp joint gave way...plus several cans that didn't open up still have their tops popped convex.

Unfortunately, I've experimented with this myself...

 

[Woolman]

Perhaps it was the heat of the engine running in an enclosed garage that did it. But... if the cans opened from heat while in the location shown in the picture there should be quite a sticky mess.

There are actually two kinds of Pepsi in the picture. I am going to guess the guy wanted to do a taste test and impatiently put them in a freezer to chill. They blew up then he took them out. Later on he died.

 

[DBBPhysics]

I read the article, then came here because I googled that same question. I have a solution to the mystery of the exploded cans.

A father was living in the house. He was the one who was killed by the CO. The son inspected the house after the incident. He found the exploded soda cans.

My theory is that those cans had exploded before the CO incident. Perhaps the father had left them in a hot car and they exploded. He just took them and put them in the garage. Later (perhaps years later) the father was killed by CO. So there is no connection between the exploded pepsi cans and CO. Mystery solved.

In light of the fact that all references to the soda cans were deleted now in the article, I agree with this theory.

 

[nonphysicist]

Am I missing a photo? I don't see a picture that includes soda cans anywhere in the article.

Copied the photo from the NYT article, I will post it.

 

[Drakkith]

Copied the photo from the NYT article, I will post it.

Thank you! That picture was nowhere to be found when I looked at the article.
Perhaps the cans exploded because of the heat?

 

[russ_watters]

In light of the fact that all references to the soda cans were deleted now in the article, I agree with this theory.

The problem with this theory is that it requires an entire back-story including several assumed actions that don't make sense. It's possible, but Occam and I prefer simpler explanations.

 

[James Demers]

Perhaps the cans froze over winter and ice pushed out the tops?

In Boca Raton? Not likely!

The culprit was undoubtedly heat. Check out a can of Coke left in a car in the hot sun:
http://www.philly.com/philly/news/y...nough_to_explode_a_Coke_can_inside_a_car.html

Look familar? The heat drives the CO2 out of solution, cramming the gas into the small dead space above the liquid. When the lid blows off, the gas escapes, and the liquid is left sitting there largely undisturbed.
(The drink in the yellow cans is Yoo-Hoo, which is not carbonated and is therefore immune to this problem.)

Possibly related to the heat from a running engine, in a closed garage, in Florida, but it has nothing to do with the carbon monoxide.

 

[gary350]

Any cold liquid that contains water will adsorb carbon dioxide. Some people claim hot beer & Hot soda is bad because all the carbon dioxide is released at about 85 degrees. Carbon dioxide is still inside the un opened can but no longer adsorbed in the liquid, pressure will be higher in a hot car or in the hot sun. If you put un opened containers of hot beer & soda in the refrigerator for 1 week in cold temperature carbon dioxide is adsorbed back into the liquid. If you throw a cold soft drink into the air nothing much happens when it hits the ground. If you throw a hot soft drink into the air when it hits the ground it explodes. That is the physics of carbon dioxide not sure how that applies to carbon monoxide unless HOT car engine exhaust causes soft drinks to explode.

 

[darth boozer]

At the bottom of the article:

"Correction: May 14, 2018
An earlier version of this article included a quotation from a family member of a carbon-monoxide poisoning victim that referred incorrectly to the cause of an explosion of Pepsi cans in the victim’s garage at the time of the fatal episode. (The error was repeated in a caption.) The explosion of the soda cans was most likely caused by heat; a carbon-monoxide buildup would not cause such an explosion."

 

[rootone]

Excessive CO2 will kill you, excessive CO kills you quicker,

 

[trainman2001]

In modern cars with effective catalytic converters, the amount of CO is very, very low. Cars are no longer an effective source of CO. Bad furnaces can produce a lot of CO as can a fireplace with a closed damper. CO2 will kill you, but again, how much CO2 would have to be loaded into a home from a garage to become lethal? There are places where CO2 can be lethal quickly. When fermenting any biologic that's going to make distilled spirits, the gas given off by the yeast is CO2 (they're living things eating sugar). I'm familiar with a modern distillery here in Louisville that has eight 24,000 gallon fermenters and they produce copious amounts of CO2. It is heavier than air and can collect in the lower reaches of the plant. There is an extraction system so it is constantly moved out, but if that fails, there are alarms to prevent humans from going into those spaces without an air pack. In high concentration, CO2 will kill you very fast and rather painlessly.

 

[russ_watters]

Excessive CO2 will kill you, excessive CO kills you quicker,

It of course depends on how much.

In a previous post, I mentioned the suicide by car tactic, where you use a garden hose to pipe exhaust into the car cabin. With this tactic, there should be almost no carbon monoxide in the car cabin (per previous post about how little CO cars actually produce*), but after just a few minutes pretty much all of the air will be replaced by CO2 and water vapor. Thus it is my belief that it would be CO2, not CO, that would kill you.

*Short version: in order to produce a significant amount of CO you need to significantly choke-off the oxygen supply to the combustion and the car ECM has to be unable to compensate. In other words, in order for the engine to produce a significant amount of CO it first has to replace a significant amount of air in the garage with CO2. If you pipe your exhaust into the cabin of the car, the engine is getting normal, fresh air for a while, so it should be producing almost no CO.

 

[russ_watters]

In high concentration, CO2 will kill you very fast and rather painlessly.

And for that reason, it is used to euthanize animals.

 

[A.T.]

It of course depends on how much.

You need much less CO than CO2.

https://en.wikipedia.org/wiki/Carbon_monoxide_poisoning#Signs_and_symptoms
https://en.wikipedia.org/wiki/Hypercapnia#Tolerance

Thus it is my belief that it would be CO2, not CO, that would kill you.

In some scenarios maybe. But here the victim was found in the house, not in the garage. Reaching lethal levels of CO2 in the entire house seems unlikely. The article names CO as the cause of death, and states that the levels in the house were "at least 30 times the level that humans can tolerate". This cannot refer to CO2.

 

[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.