Any truth to Air Companies wanting to ease your final moment?

The idea that breathing pure O2 will make you dizzy, high, euphoric is utter and complete bullshit.

During my years as an E.M.T., I administered O2 dozens and dozens of times. Both my small portable tank in the car, the larger tank we pulled in on calls and the huge tanks in the rigs were filled with 100 % pure oxygen.

I cannot recall a single instance where any patient of any age suffered any level of behavior changes as a result of breathing in O2. Some of them, during long distance transport, had O2 masks affixed to their faces for more than an hour. ( These are non-rebreather masks. Nasal cannulae of course allow for a controlled small flow of O2 that mixes in with room air breathed normally. )

Granted, these all took place at sea level- 1 atmosphere.

I don’t think the altitude would in of itself create euphoria while breathing O2. It just sounds like urban legend crap.


Just don’t breathe 100% oxygen when diving below 30 feet or so or any place where the pressure is above 2 atmospheres. Under those conditions, oxygen quickly becomes unfriendly…

In the context of an aircraft passenger, yes it is bullshit. But if you breath high partial pressures of oxygen for a long time, you can get oxygen toxicity.

You can attain high partial pressures of oxygen by either breathing a mixture of gasses including oxygen (e.g., air) at higher than standard atmospheric pressure, or by breathing a high concentration (50% or more) of oxygen at standard atmospheric pressure.

It’s been stated before, but it’s the LACK of oxygen which would make you euphoric and calm.

As they used to tell us over and over agian when I did my Private Pilot’s Ground School class: “If everything is going perfectly fine, check your oxygen.”

TD is full of IT!
TD is either ignorant or stupid or …

-sigh- Allow me to reiterate. When delivering 15 lpm of 100 % 02 at ground level ( standard atmosphere 1 ), I never witnessed anything akin to oxygen toxicity.

Not ever. Nor, as I peruse my Emergency Medical Technician’s class manual, is there mention of endangering a patient by affixing onto their face a non-rebreather mask delivering 15 lpm of 100% O2.

So, no offense, but a cite proving that at ( nominal ) ground level, you will induce oxygen toxicity by allowing a patient to breathe 100% O2?

I gave a cite. You probably haven’t seen it because you have to breath oxygen for a long time to get it. 16 hours at 0.5 bar according to the cite I gave.

Guys, get on the same page. .5 bar is 1.5 atmospheric and is like diving to 16 feet with 100% oxygen, takes a while but is bad. 100% oxygen at seal level = 1 atmosphere, 0 bar is okay unless the mask is sealed so that additional pressure can be maintained. You are both right, just talking about different things.

At 3 atmospheres or about 99 feet deep, 100% oxygen gets lethal real fast.

If you go so high or into such a low ( - ) bar situation, like 45,000 feet up, you don’t have the partial pressure for you lungs to work properly and you would need a pressure system to get the partial pressure up enough to survive.

100% oxygen environment is most certainly survivable long term if the pressure is ½ normal atmosphere absolute.


I have no idea whether oxygen makes you calm and euphoric or not. But speaking personally, if I’m on a plane that’s spinning into terra firma at terminal velocity, I’d appreciate something that will make my final moments calm and euphoric rather than horrible and terror-stricken. Dang, they should make the drinks free too.

Standard atmosphere is 1013.2 mbar, or 1.0132 bar. Which makes 0.5 bar about 17,000’ up, not 16’ down, or do divers use a different interpretation of a bar?

There are two ways to measure pressure. You can use sea level as zero, and go up from there, or you can measure pressure over a vacuum.
I don’t have a dog in this hunt, but I do run into specifications written both ways.

I know several balloon pilots who have hung at that altitude and higher while on 100% Oxygen for more than 36 hours, they must have just been lucky.

You need to notify the FAA and the Air Force because they don’t seem to have the same info.

I still feel we are not communicating well. Something is being left out. Not sure what it is.

In certain conditions ( below 33 feet in water) or chambers where the pressure is more than ‘normal’ 100% oxygen can be lethal. At one atmosphere, sea level, I have never heard of 100% Oxygen being harmful. At less than one atmosphere, I really doubt it is harmful.

So what conditions are you using oxygen at altitude to make it harmful? Forcing it into the lungs and over inflating them? Creating an artificial condition in the lungs of more than one atmosphere?

I don’t think we are on the same page yet. At least not where 16 hours is the dividing line.

The lungs work adequately from about 10 feet under water to 35,000 feet above sea level, however you want to measure it. In that range, the ‘partial pressure’ is in the range that lungs can do the lung thing. Out side of that range, we have to help in various ways and the oxygen can be in the wrong concentration.

Within the ‘partial pressure’ range described, I have not heard of a oxygen problem due to time of such short duration.

What were the actual conditions and what was the subject doing when this harm occurred?

There’s not even any reason for the airlines to go out of their way to make last moments more comfortable, unless they advertise the fact to get more business.

“Honey, which airline should we use to book our trip to Europe?”
“USAir! If the plane starts going down they get you high! By the time you hit the ground, you’re so fucked up you don’t care! Those bastards at Delta don’t even let you light up a cigarette before you die.”

Voiceover: “USAir. We get you fucked up before we kill you.”

Our inflight movie will be “The Freak”. It will fuck you up for life. What little you have left, anyway.

If they were higher then they can breath 100% for as long as they like.

At any rate, various websites quote different levels of oxygen as being harmful. There are a lot that say more than 16 hours at a partial pressure of 0.5 bar. They also say that it varies greatly between individuals and the effects are greater with increased time. It seems to me that 16 hours at 0.5 is conservative. I’m not sure just how conservative or why/how this dividing line is quoted.

I don’t know what the military use, but airliners are fitted with a pressure/demand mask that, when in demand mode, increase oxygen up to 100% at about 34,000’ which is well outside any cited range for toxicity. Even if 16 hours at 0.5 bar is accurate, it seems highly unlikely that any pilot would be tooling around at 17000’ or lower for that long on 100% oxygen. You’d think they’d use a demand mask to conserve their O2 supply, or be flying a whole lot higher.

My point never was that 100% oxygen is harmful at altitude. My point was that 100% oxygen at sea level can be harmful and was in response to Cartooniverse saying he’d never seen any harmful effects from 100% O2. The 0.5 bar was just part of the cite I used, but wasn’t the point of the post. It wasn’t even meant to refute what he said, it was meant more as additional information.

It is clear that he wouldn’t have seen any effects because he would never have delivered 100% O2 for long enough. It only seems to be a problem for intensive care patients, and sometimes divers, though CNS O2 toxicity is the primary threat to them.

There are two types of oxygen toxicity, pulmonary, and CNS (central nervous system.) Pulmonary oxygen toxicity is the one that occurs after a long time breathing relatively high partial pressures of O2. CNS oxygen toxicity requires higher than atmospheric pressures and also occurs in a relatively short time. It cause convulsions, blurred vision, and nausea and is the primary concern of divers.

From, referring to pulmonary oxygen toxicity,

I don’t know enough about it to be able to judge whether the 16 hours at 0.5 bar is accurate or not. A lot of places quote it, but as I said, there are some with more generous limitations, including one written by a PhD who said that 100% oxygen continuously at sealevel is fine. That directly contradicts everything else I’ve read about it though. You’d probably be best to google “oxygen toxicity” and make your own judgement.

IT may also be that they are talking about 0.5 bar relative to atmospheric, not as an absolute pressure. They don’t specify.

It is clear though, that long exposure to 100% O2 at sealevel is harmful.

Okay, long enough and far enough from normal air will eventually get ya. I agree.

I must add though that in the grand scheme of things, * A long exposure to a 100% lack O2 at sea level. * is a more serious threat.

Is there a published caution for back to back transoceanic flights and the possibility of oxygen poisoning for flight crews of big iron?

Is there a published caution for back to back transoceanic flights and the possibility of oxygen poisoning for flight crews of big iron?

No. Mainly because big iron flight crews don’t breath 100% oxygen. And if they did, it would be at pressures far below 1 bar or even 0.5 bar. So it is not a threat for flight crews (and I wasn’t saying it was.)