[radiohead]

Finally, at the "death zone", 8,000 m and higher, no human body can acclimatize. Staying longer than necessary will result in deterioration of body functions, loss of consciousness and ultimately, death.

Does this mean that even with oxygen, climbers are going to have problems?

What I'm grappling with is, if they have bottled oxygen, what is the problem? If they can't bring enough, I guess that's one thing, but it seems that bottled oxygen should solve, or at least reduce the problem, unless even bottled oxygen at that altitude isn't very helpful.

[hattend]

If you are breathing oxygen through a cannula or simple oxygen mask (you breath it in on your own) then you can never get enough oxygen to provide you what you need while in the death zone. No matter how much oxygen you have, you can't stay there.

Above 8000 meters, you need a pressurized oxygen mask that blows oxygen into your lungs (you make the effort to expel your breath which is opposite of what is normal). Much higher than that and you need a pressure suit or a pressurized cockpit to stay alive

[hattend]

If you can find the book "The Long Lonely Leap" (Capt Kittenger), give it a read.

It pretty much explains the whole oxygen at altitude thing. He went to 100K feet just to jump out...very interesting read.