It's carbon dioxide (can cause suffocation)

Fires kill very few people caught in house fires. Yes, sure, fire is bad but it's the smoke that kills. Between the smoke and the raging fire DEVOURING all of the oxygen in the air, you have a recipe for disaster.

That kid's stunt for even 20 or 30 seconds could have ended up with him in serious risk.

CO2 is very dangerous, and not JUST for the asphyxiation risks. It changes the PH Balance in your blood. It can lead to Nerve Damage, Hypercapnia, Stroke, Brain Damage not to mention the hell it reaks on all of your organs until your blood has filtered out all of the acid.

Low surges of CO2 are perfectly fine, but 2 Deep breaths of that air could have easily sent him into a downward spiral he may have never returned from.

Always be safe when working with any dangerous materials, dry ice included.

www.blm.gov/style/medialib/blm/wy/information/NEPA/cfodocs/howell.Par.2800.File.dat/25apxC.pdf

Yeah, No. At just 5% CO2 levels, you're already effecting the heart. At 30%, Coma, Convulsions and Death begin to show at around 5 minutes. That cloud he's laying in? At least 30%.

CO2 is NOT non-toxic. It's the very definition of Toxic. Exposure to CO2 at a high enough %(Like flooding your floor with it and lying in it) can, and will, kill you.

Low dosages can cause headaches, dizziness and vomiting. High dosages can cause respiratory failure, coma, brain damage, breathlessness, increased heart rate & blood pressure, distortions, migraines, impaired hearing, loss of consciousness, convulsions and death. Not due to asphyxiation - due to acidosis.

CO2 is carbon dioxide, not carbon monoxide (which is CO)

Your body triggers a panic reflex when you have to much CO2 in your blood. Suffocating that way is extremely painful, so if he did start to suffocate by laying down, he'd immediately scramble to get up into a more oxygen rich environment.

Carbon monoxide on the other hand is an industrial waste gas (also comes from car exhaust). It displaces oxygen in your blood, but doesn't trigger the panic reflex. It's a painless way to go, which is why CO detectors are a thing (and important to have if your house has any natural gas appliances like a gas furnace).

There is no such thing as CO2 poisoning so goolge assumed it was a typo. CO2 is non toxic, but it displaces the air so it will suffocate you if you breathe only it, CO is a poison that binds to the hemoglobin in your blood meaning your blood can;t carry oxygen and you die

CO2 poisoning is called Hypercapnia or CO2 Retention. At just 6 minutes, 7% CO2 in the air can cause mental confusion and dyspnea, potentially keeping you from escaping your scenario. This can onset much faster at higher %s. The fumes he's inhaling is probably around 60%.

CO2 is, by definition, a toxin to your system. It's one your system lives with, but at a cellular level it is toxic.( - www.ncbi.nlm.nih.gov/pubmed/16499405 ) Once you break 10%, long term exposure can lead to severe negative responses from your body. At 30%, at only about 5 minutes, it can send you into a coma and if not treated, even take your life. The cause of death is due to a PH balance issue in your blood stream and your kidney/s basically doing its job.

Just some readings, if you care enough:

inspectapedia.com/hazmat/Carbon_Dioxide_Hazards.php
www.blm.gov/style/medialib/blm/wy/information/NEPA/cfodocs/howell.Par.2800.File.dat/25apxC.pdf

CO2 is not a safe material. Always be careful with any material you work with.

I wasn't trying to be a dick, just trying to get you on the right track. No need to get all defensive.

Carbon monoxide is pretty ugly too! It's 200 times easier for the lungs to absorb and you dont feel that you are running out of air like you do with CO2. Also it absorbes oxygen that is already in the blood.

Well... Then I just learned something new!

He wouldn't have passed out. Too much CO2 is extremely painful.

It's frozen carbon dioxide.
At atmospheric pressure it sublimates to form the gas state when it heats up.
Since it's heavier than air it tends to sink down (especially in confined spaces with low air circulation) and when you inhale it, it replaces the oxygen in your lungs.
So just lay down, take a deep breath and relax. Forever.

Him laying down in carbon dioxide is the equivalent of placing a plastic bag on your head. Stupid, but not abruptly deadly. Typically, humans have a strong reflex to get fresh air. Plus carbon dioxide doesn't take the place of oxygen. It can't. Carbon monoxide, on the other hand...

It doesn't replace it in the hemoglobin (in the bloodstream) but you'd still be breathing a gas that contains no oxygen.
Yes, the body has some reserves but and an increased CO2 in the bloodstream s0hould trigger a strong urge to breathe. If you're smart you'll get up then - if you don't get it and keep down you might get into trouble.
With the plastic bag at first you still have normal air and the only CO2 is the one you produce over time. When you take a deep breath of almost pure CO2 the effect is more instant and much stronger. Not abruptly deadly but at the point you loose consciousnes and are alone (which he gladly isn't) you might be done for

ive held dry ice before, in my chemistry class... you can hold it for a few seconds as long as you keep it moving, thanks to the leidenfrost effect

Actually, though it is dangerous, because of suffocation. Its not exactly harmful, because all it does is take the physical space of much needed oxygen... The problem is 2 fold, firstly from a laying position, going unconscious means you are unable to stand up, and get out of the fog. and secondly the oxygen in a single breath of air, can actually last quite a while.. so by replacing that oxygen, your actually causing yourself to suffocate faster than your instincts believe possible (so instead of that feeling you get when you cant hold your breath, you simply pass out) But once it has left your lungs.. there is no lasting damage..

Carbon Monoxide on the other hand, binds directly to the oxygen receptors in your lungs.. so even if you successfully get to fresh air, you could still potentially die from lack of oxygen... (basically you'll just feel really tired.. and may or may not wake up)