Why does breathing pure oxygen kill you?

Question

Why does breathing pure oxygen kill you?

Answer 1

Any gas is toxic if it provides too much imbalance to the natural air you breathe. Even oxygen (it'll burn your lungs).

If enough natural gas was in the air, the concentration alone might be high enough that your pet was breating in more of that than air and suffocated.

Answer 2

Doesn't what kills us make us stronger.

Answer 3

Oxygen literally burns cells.

Did you know that there's more Nitrogen in the air we breathe, than Oxygen?

Answer 4

Read this.

Answer 5

it is dangerous because your body doesn't only need oxygen but other gases too. and scientists say that oxygen is poisonous but not on earth because we have evolved to neutralize that poison which is oxygen to us which it can be useful. oxygen is poisonous because for example nail a clean unpainted nail when you leave it to oxygen it will rust and when apples is exposed to oxygen it will brown. That is the reason why we buy anti oxidant to remove oxygen too much oxygen only. some say that is th reason cannot live on earth.

Answer 6

It damages cells in the nervous system and in the lungs if at HIGH pressure. A human can survive in pure oxygen for short lengths of time so long as the pressure is low. But ultimately it damages cells with longer exposure.

Answer 7

Some interesting answers. You are correct that breathing pure (or perhaps more accurately higher than normal concentrations of) oxygen can kill you but this is often as an indirect effect of a condition known as oxygen toxicity. For example divers breathing pure oxygen from a tank can lose conciousness and drown as a result of this. It is actually lack of oxygen through drowning that has killed them but the oxygen toxicity that induced the unconsciousness that caused this.

Perhaps some of the confusion that appears to have arisen here is due to the fact that the exact mechanism by which oxygen damages the body's cells is not clearly known. Therefore you may not get a comprehensive answer to your question. Oxygen as you know is a highly reactive gas. It is thought that in the body highly reactive components of oxygen gas known as reactive oxygen species (more of which will be present at higher oxygen concentrations) can react and attack unsaturated fatty acids in cells. Free radicals (a specific type of reactive oxygen species) also harm DNA. Fatty acids form an essential component of the cell membrane and DNA is essential for cell repair and replication. Obviously if the damage is great enough this will eventually result in cell death.

As you can see it is quite hard to explain even the proposed mechanisms of damage without going into quite a lot of detail. A simpler explanation would be to say that at normal concentrations of oxygen the body is equipped to cope with the damage it causes. However at higher concentrations it becomes overwhelmed.

Finally I'd perhaps like to clarify the matter of 'pure' oxygen. Under normal circumstances one breathes in oxygen from the surrounding air at a concentration of just over 20%, the majority of the other 80% being made up of nitrogen.

If I were to wire you up to a cylinder of pure oxygen for a minute or two there would not be any noticeable effects, even though you are breathing 100% oxygen it would take some time, perhaps days, for there to be any harmful effects. If however you were to go diving with a cylinder of pure oxygen at a depth of about 10 meters you would in effect be breathing 200% oxygen (more correctly referred to as a partial pressure of 2 bar) because the pressure at 10 meters is roughly double that of normal atmospheric pressure. At this level it would be more likely that you would experience the effects of Central Nervous System oxygen toxicity such as convulsions and unconsciousness.

Essentially the higher the concentration (or partial pressure) of oxygen you are breathing, the more likely you are to have problems. For all it's bad effects though it is probably a lack of oxygen (for example breathing pure nitrogen) that poses the greater risk for human life.

Answer 8

It doesn't kill you.  Surgeries and recovery for respiratory distress (e.g. drowning) often use pure oxygen (to the best of my knowledge...they definitely did in the past).

However, pure oxygen can be dangerous.

1. It's much easier to cause a fire with pure oxygen; I remember seeing a TV program about how surgical tools would on rare occasions, trigger fires because patients were given pure oxygen

2. Pure oxygen is toxic over long periods of exposure (likewise, lower concentrations are toxic at increased pressures).  This is primarily due to the formation of reactive oxygen species, which can damage DNA, tissues and cells.