# Would you get sick breathing Carboniferous air? (V. high O2 content) **URL:** \ **Category:** Factual Questions\ **Created:** [March 3, 2020, 3:58pm UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875 "2020-03-03T15:58:06Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [March 6, 2020, 3:46am UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/21 "2020-03-06T03:46:53Z")
Of course there were fire-breathing dragons! They ate limestone and exhaled hydrogen which they ignited with an electrical organ in their throat. Watch the documentary film The Flight Of Dragons. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [March 6, 2020, 4:14am UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/22 "2020-03-06T04:14:47Z")
> [@racer72](#): > > Anything over 23.5 percent will make your body do weird things. [More info here.](https://sciencing.com/minimum-oxygen-concentration-human-breathing-15546.html) All that sez is "_Too Much Oxygen: Side Effects Higher-than-normal oxygen levels aren’t as harmful to life, but there is an increased change of fire or explosion risk. With extremely high concentrations of oxygen in the air, humans can experience harmful side effects. Very high levels of oxygen cause oxidizing free radicals to form. These free radicals attack the tissues and cells of the body and cause muscle twitching. The effects from short exposure can most likely be reversed, but lengthy exposure can cause death._ I dont think 35% is “extremely high concentrations of oxygen”. ---
**Author:** ![Paul\_in\_Qatar](https://avatars.discourse-cdn.com/v4/letter/p/ccd318/32.png) [@Paul\_in\_Qatar](https://boards.straightdope.com/u/Paul_in_Qatar)\ **Post date:** [March 6, 2020, 4:22am UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/23 "2020-03-06T04:22:46Z")
> [@DocCathode](#): > > Watch the documentary film The Flight Of Dragons. When they died the acid in their guts solved all the bones. The fact there is no proof is in itself evidence. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [March 6, 2020, 1:07pm UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/24 "2020-03-06T13:07:21Z")
I recall that way back when (60’s? 50’s?) for a while pure oxygen had been part of the treatment for premature babies whose lungs were not fully developed - until they realized it cause blindness - I think due to uncontrolled growth of blood vessels in the retina. A side effect of oxygen partial pressure I recall reading was that the level was self-regulating because too high a partial pressure made flora easier to burn\> That high level should have resulted in massive forest fires - not sure why this was not so, unless those giant forests were particularly damp. Also one of Asimov’s non-SF novels revolved around a murder attempt in academia where someone smeared petroleum gel on an oxygen fitting. The claim was when used with extremely compressed oxygen, it would explode. There was some question whether the pure oxygen (albeit, 5psi) was responsible for the Apollo fire that killed 3 astronauts during capsule testing, helping everything burn. Because internal pressure was much lower than outside, they could not open the hatch (outward). 100 feet down is 4 atmospheres (the regular one plus an extra 3) so oxygen partial pressure would be the same as about 80% oxygen at sea level. I knew an old lady once, many moons ago, whose first husband was a sniper in WWI (!) and spend years in a veterans hospital in an oxygen tent missing a lot of his lungs. The big problem in those days was monitoring those guys to make sure they did not try to smoke. (Yikes!) I suppose high O2 partial pressure was compensated for by poor lung performance. ---
**Author:** ![brossa](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/brossa/32/3040_2.png) [@brossa](https://boards.straightdope.com/u/brossa)\ **Post date:** [March 6, 2020, 1:30pm UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/25 "2020-03-06T13:30:04Z")
The Apollo test was run with pure O2 at 2 psi above ambient air pressure, not at 5 psi. The door could not be opened because it was a plug design, and the pressure inside the capsule was higher than sea level - initially because of the intentional overpressure, but also due to cabin air pressure increase due to heating (the fire). ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 6, 2020, 2:16pm UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/26 "2020-03-06T14:16:08Z")
> [@md2000](#): > > There was some question whether the pure oxygen (albeit, 5psi) was responsible for the Apollo fire that killed 3 astronauts during capsule testing, helping everything burn. Because internal pressure was much lower than outside, they could not open the hatch (outward). There is no question. As **brossa** points out, the capsule pressure was 2 psi above ambient - meaning the capsule was filled with pure O2 to an _absolute_ pressure of 16.7 psi. This was the factor that transformed many of the items in the capsule from “marginally combustible” in an ordinary atmosphere to “violently flammable;” all it took was one ignition source to get it going. > **[Apollo 1 | Pure oxygen atmosphere](https://en.wikipedia.org/wiki/Apollo_1#Pure_oxygen_atmosphere)** > > The plugs-out test had been run to simulate the launch procedure, with the cabin pressurized with pure oxygen at the nominal launch level of 16.7 psi (115 kPa), 2 psi (14 kPa) above standard sea level atmospheric pressure. This is more than five times the 3 psi (21 kPa) partial pressure of oxygen in the atmosphere, and provides an environment in which materials not normally considered flammable will be highly flammable and burst into flame. > The high-pressure oxygen atmosphere was similar to that... > [@Wikipedia](#): > > The plugs-out test had been run to simulate the launch procedure, with the cabin pressurized with pure oxygen at the nominal launch level of 16.7 psi (115 kPa), 2 psi (14 kPa) above standard sea level atmospheric pressure. This is more than five times the 3 psi (21 kPa) partial pressure of oxygen in the atmosphere, and provides an environment in which materials not normally considered flammable will be highly flammable and burst into flame. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [March 6, 2020, 7:08pm UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/27 "2020-03-06T19:08:53Z")
Interesting - I had always thought the hatch opened outward and pressure kept it closed when they wanted to open it. ---
**Author:** ![Atamasama](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/atamasama/32/12961_2.png) [@Atamasama](https://boards.straightdope.com/u/Atamasama)\ **Post date:** [March 6, 2020, 8:41pm UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/28 "2020-03-06T20:41:11Z")
> [@Paul\_in\_Qatar](#): > > When they died the acid in their guts solved all the bones. The fact there is no proof is in itself evidence. If the acid was that strong you’d think it would dissolve their bones while they were alive. Science sure is funny! ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [March 7, 2020, 2:07am UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/29 "2020-03-07T02:07:59Z")
> [@md2000](#): > > . . . There was some question whether the pure oxygen (albeit, 5psi) was responsible for the Apollo fire that killed 3 astronauts during capsule testing, helping everything burn. Because internal pressure was much lower than outside, they could not open the hatch (outward). If the American space effort had known in 1967 what happened in the Soviet program in 1961, things might have been designed differently to make such a disaster less likely and/or more survivable. In 1961, Soviet cosmonaut-in-training Valentin Bondarenko got incinerated alive in a similar training accident. Burnt to a near-crisp from head to his ankles, he lived for 8 hours before he died. As with Apollo, they had a hard time opening the hatch to get him out quickly. The Soviets kept such things secret for a long time. The Bondarenko story came out in 1986. The story is told in gruesome detail here (starting about 18 paragraphs down the page): [Uncovering Soviet Disasters: Chapter 10: Dead Cosmonauts](http://www.jamesoberg.com/usd10.html) by James Oberg, 1988. > [@](#): > > Bondarenko had been undergoing routine training in a pressure chamber, which was part of a ten-day isolation exercise. At the very end of the exercise he made a trivial but fatal mistake. “After medical tests,” explained Golovanov’s article, "Bondarenko removed the sensors attached to him, cleaned the spots where they had been attached with cotton wool soaked in alcohol, and without looking threw away the cotton wool-- which landed on the ring of an electric hot plate. In the oxygen-charged atmosphere the flames immediately filled the small space of the chamber. > > Under such a condition of high oxygen concentration, normally nonflammable substances can burn vigorously. The cosmonaut’s training suit caught fire. Unaccustomed to the vigor of high-oxygen fires, Bondarenko would only have spread the flames further by attempting to smother them. > > When the doctor on duty noticed the conflagration through a porthole, he rushed to the hatch, which he could not open because the internal pressure kept it sealed. Releasing the pressure through bleed valves took at least several minutes. And for ail that time Bondarenko was engulfed in flames. Farther down the page, the story continues with the grisly detail of what happened with Bondarenko after they got him out, until he died. Warning: Extreme TMI! ---
**Author:** ![Paul\_in\_Qatar](https://avatars.discourse-cdn.com/v4/letter/p/ccd318/32.png) [@Paul\_in\_Qatar](https://boards.straightdope.com/u/Paul_in_Qatar)\ **Post date:** [March 7, 2020, 2:27am UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/30 "2020-03-07T02:27:12Z")
> [@Atamasama](#): > > If the acid was that strong you’d think it would dissolve their bones while they were alive. Science sure is funny! When an arrow pierced the protective lining of the stomach the acid/hydrogen mixture escaped rapidly and sometimes explosively. This is recounted in all the standard histories. A natural death was less exciting. The acid dissolved the body in a limestone cave leaving only the gold and other noble metals the dragon used in his crop. Again, this is just basic biology. ---
**Author:** ![Paul\_in\_Qatar](https://avatars.discourse-cdn.com/v4/letter/p/ccd318/32.png) [@Paul\_in\_Qatar](https://boards.straightdope.com/u/Paul_in_Qatar)\ **Post date:** [March 7, 2020, 2:37am UTC](https://boards.straightdope.com/t/would-you-get-sick-breathing-carboniferous-air-v-high-o2-content/848875/31 "2020-03-07T02:37:30Z")
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