WEBVTT - From the Vault: Hair on Fire, Part 1 0:00:06.160 --> 0:00:08.440 Hey, you welcome to Stuff to Blow your Mind. My 0:00:08.560 --> 0:00:11.280 name is Robert Lamb. Today is Saturday, so we have 0:00:11.440 --> 0:00:13.480 a vault episode for you. This is going to be 0:00:13.880 --> 0:00:17.320 Hair on Fire, Part one, which originally published seven eighteen, 0:00:17.720 --> 0:00:22.560 twenty twenty four. There's a lot to talk about here, chemistry, mythology. 0:00:22.680 --> 0:00:25.479 It's one of those episodes. So let's dive right in. 0:00:28.920 --> 0:00:32.680 Welcome to Stuff to Blow Your Mind, production of iHeartRadio. 0:00:38.560 --> 0:00:40.720 Hey you welcome to Stuff to Blow your Mind. My 0:00:40.840 --> 0:00:42.120 name is Robert Lamb. 0:00:42.040 --> 0:00:45.400 And I am Joe McCormick. And today on Stuff to 0:00:45.440 --> 0:00:49.360 Blow Your Mind, I wanted to talk about burning hair. 0:00:49.640 --> 0:00:52.920 That might be a kind of unusually niche or weird 0:00:53.320 --> 0:00:55.680 thing to look into. But I was inspired to do 0:00:55.760 --> 0:00:57.840 this a couple of weeks ago, on the fourth of 0:00:57.920 --> 0:01:01.880 July actually, when I was making food for a for 0:01:01.880 --> 0:01:03.680 a big family get together. You know, I was out 0:01:03.680 --> 0:01:07.120 in the backyard grilling, and I did something I have 0:01:07.240 --> 0:01:10.760 done many times before, which is burn all the hair 0:01:10.800 --> 0:01:13.959 off part of my arm. Oh no, yeah, turn and look. 0:01:14.000 --> 0:01:17.600 I mean like I wasn't like badly burned myself, like 0:01:17.640 --> 0:01:19.760 on my skin. But you know, at some point I 0:01:20.080 --> 0:01:21.959 look down and realized, like Oh, what are all these 0:01:21.959 --> 0:01:23.880 weird little kind of pale curls? 0:01:24.200 --> 0:01:28.080 Oh? I see, Okay, do you say you've done this before? 0:01:28.200 --> 0:01:30.360 Do you at least alternate arms or is it just 0:01:30.400 --> 0:01:31.840 always the same arm that it gets? 0:01:32.120 --> 0:01:34.400 It's always my right arm, because that's the arm I'm 0:01:34.480 --> 0:01:37.360 right handed doing that, you know, that's what I'm manipulating 0:01:37.400 --> 0:01:39.880 the food with. You know. Sometimes it's more the hand, 0:01:40.080 --> 0:01:42.840 like the I don't know if it's gross to talk 0:01:42.840 --> 0:01:45.480 about your hand hair, like the hair on my knuckles, 0:01:45.520 --> 0:01:47.200 the hair on my back, the back of my hand 0:01:47.720 --> 0:01:50.040 that gets burned off. This time it was mainly along 0:01:50.120 --> 0:01:52.840 like my forearm and the outside of my wrist. I 0:01:52.920 --> 0:01:56.600 wonder if other grill operators have had similar experiences, because 0:01:56.640 --> 0:02:01.280 I I never burn my hand or arm here when 0:02:01.280 --> 0:02:03.919 I'm grilling a small amount of food, like a couple 0:02:03.960 --> 0:02:06.560 of portions of whatever. It's always when I'm grilling for 0:02:06.640 --> 0:02:09.520 a big crowd. So I guess it has something to 0:02:09.560 --> 0:02:12.320 do with like trying to like fit a bunch of 0:02:12.320 --> 0:02:15.720 different individual items on the grill and then go down 0:02:15.760 --> 0:02:17.959 the line flipping them or moving them one at a time, 0:02:18.040 --> 0:02:21.120 and something about that means like I'm holding my arm 0:02:21.240 --> 0:02:24.000 directly over the hot part of the grill more or something. 0:02:24.639 --> 0:02:26.480 Well that that would make sense, because I was thinking 0:02:26.480 --> 0:02:28.079 about this as like, Okay, I don't know that I've 0:02:28.080 --> 0:02:32.040 ever done this myself, but I think look back on 0:02:32.120 --> 0:02:34.320 all on the grilling I have done over the years, 0:02:34.639 --> 0:02:38.840 and it is generally just grilling for probably just for 0:02:38.919 --> 0:02:40.880 my immediate family, So it's feeling just for like two 0:02:41.000 --> 0:02:43.639 or three people. It's probably just going to be veggies 0:02:43.680 --> 0:02:47.200 that aren't on there very long. And yeah, for I 0:02:47.200 --> 0:02:49.440 guess a variety of reasons, and luck I have not 0:02:49.919 --> 0:02:53.200 like burnt a lot of arm here on the grill, 0:02:53.280 --> 0:02:55.520 but I have to, so I have to ask like 0:02:55.560 --> 0:02:58.360 the follow up questions like what you mentioned what it 0:02:58.400 --> 0:03:01.120 looked like, but that it was was that the primary 0:03:01.160 --> 0:03:03.040 way that you realize something had happened or was there 0:03:03.120 --> 0:03:06.360 also like a skin level sensation And was there a smell? Uh? 0:03:06.440 --> 0:03:09.760 I mean, there's the feeling of heat obviously, which but 0:03:10.000 --> 0:03:12.240 that's just naturally the air, because like I'm reaching over 0:03:12.280 --> 0:03:16.400 a hot fire, I think there is a smell normal. 0:03:16.800 --> 0:03:19.480 In fact, I would say that the smell is probably 0:03:19.560 --> 0:03:24.200 the most characteristic and instantly recognizable sensory part of the 0:03:24.200 --> 0:03:27.640 burning hair experience, right. I mean, almost anybody I think 0:03:28.280 --> 0:03:31.440 can immediately think of the smell of burning hair. It 0:03:31.440 --> 0:03:34.600 seems to stick in people's minds, even if hair burning 0:03:34.680 --> 0:03:37.160 is like not something that happens very often to them. 0:03:37.200 --> 0:03:39.320 It's just sort of I don't know, do you know 0:03:39.360 --> 0:03:41.040 what I mean, Like it just sort of like sticks 0:03:41.080 --> 0:03:42.720 in your memory. What that smells like? 0:03:43.120 --> 0:03:45.800 Yeah, yeah, yeah, we'd be kind of wired, I guess, 0:03:45.840 --> 0:03:47.400 to recognize. 0:03:46.880 --> 0:03:49.960 It specifically in the context of grilling, though. There are 0:03:50.040 --> 0:03:51.920 already a lot of volatiles in the air, there's a 0:03:51.960 --> 0:03:54.720 lot of smoke, a lot of particles and everything. It's 0:03:54.720 --> 0:03:59.200 an intense smell experience already, so I think the smell 0:03:59.200 --> 0:04:01.560 of the burning hair, especially if there's only a little 0:04:01.560 --> 0:04:03.160 bit of it, just kind of blends in more. You 0:04:03.240 --> 0:04:05.880 might not notice that first. In this case, Yeah, I 0:04:05.880 --> 0:04:08.440 remember just like looking down at my arm the part 0:04:08.520 --> 0:04:10.400 that had been hot, and being like, oh, yeah, that 0:04:10.480 --> 0:04:11.040 happened again. 0:04:11.800 --> 0:04:13.360 Okay that yeah, that would make sense. There are a 0:04:13.400 --> 0:04:15.920 lot of competing smells going on there. Yeah. 0:04:15.960 --> 0:04:20.200 But anyway, this experience got me wondering about the science 0:04:20.320 --> 0:04:22.800 of burning hair. I started to wonder, you know, some 0:04:23.160 --> 0:04:26.400 questions about the basic science and chemistry involved here, like 0:04:26.760 --> 0:04:31.000 how flammable is human hair and why does it smell 0:04:31.040 --> 0:04:34.359 that way? And so forth. I was looking around for 0:04:34.720 --> 0:04:38.839 good sources on the question of the sort of the 0:04:39.120 --> 0:04:44.440 underlying chemistry of the smell of burning hair, and basically 0:04:44.640 --> 0:04:48.680 the best sources I found pointed me to the presence 0:04:48.880 --> 0:04:52.800 of sulfur. Of course, hair is mostly made of keratin, 0:04:52.880 --> 0:04:57.560 which is primarily protein, and of course those proteins, when 0:04:57.600 --> 0:05:01.760 they're burned, release their own sort of there are characteristic 0:05:01.800 --> 0:05:05.400 protein burning smells that we might associate with the burning 0:05:05.440 --> 0:05:09.880 of other types of skin and even fingernails and things 0:05:09.920 --> 0:05:13.880 like that. But a big thing is the presence of sulfur. 0:05:13.920 --> 0:05:16.120 According to a paper that I'm going to mention in 0:05:16.160 --> 0:05:22.120 a little bit, human hair is approximately five percent sulfur, 0:05:22.760 --> 0:05:27.360 and that sulfur content is largely responsible for the characteristic smell. 0:05:28.160 --> 0:05:31.600 And this is interesting to me because it explains a similarity, 0:05:31.600 --> 0:05:35.279 at least as far as I can remember. That burning hair, 0:05:35.440 --> 0:05:38.360 to me, smells a little bit like lighting a match. 0:05:39.040 --> 0:05:43.160 Lighting a match produces the distinctive smell of sulfur dioxide 0:05:43.240 --> 0:05:48.520 or generally sulfur compounds, which happened because there is usually 0:05:48.600 --> 0:05:52.080 sulfur content in a match head. It's part of what 0:05:52.200 --> 0:05:55.360 burns to set the match alight. As a side note, 0:05:55.440 --> 0:05:59.920 apparently it is kind of known that you can temporarily 0:06:00.400 --> 0:06:04.440 mask other unpleasant smells. A commonly referenced one is the 0:06:04.480 --> 0:06:07.760 smell of feces by striking a match. Have you ever 0:06:07.800 --> 0:06:08.440 heard this before? 0:06:08.520 --> 0:06:10.600 Rob, Oh, yeah, yeah, of course, you know. I mean 0:06:10.640 --> 0:06:15.719 sometimes you even see that in at least residential bathrooms. 0:06:15.760 --> 0:06:19.520 You know, there will be like some matches out by 0:06:19.560 --> 0:06:21.720 the bathroom facilities, that sort of thing. 0:06:22.240 --> 0:06:24.400 Oh, that's interesting. I don't know if I ever made 0:06:24.440 --> 0:06:26.520 that connection, I would have assumed that if there were 0:06:26.560 --> 0:06:29.080 matches out, they're usually paired with the candle, and the 0:06:29.160 --> 0:06:32.120 idea is that you would use the matches to light 0:06:32.200 --> 0:06:35.120 like a pleasantly scented candle. And I always understood that 0:06:35.160 --> 0:06:38.359 as the ideas you would use a pleasantly scented candle 0:06:38.400 --> 0:06:41.440 to mask the smell of feces in a bathroom or something. 0:06:41.760 --> 0:06:44.680 I guess often but not always, I guess. And then 0:06:44.720 --> 0:06:47.560 there is also like the kind of just a saying 0:06:47.680 --> 0:06:50.040 right like, oh, there's a bad smell that may be 0:06:50.160 --> 0:06:53.640 associated with digestion. Someone will be like, oh, somebody light 0:06:53.720 --> 0:06:54.400 a match, you know. 0:06:55.120 --> 0:06:58.159 Oh okay, well, I may have misunderstood those sayings as well. 0:06:58.200 --> 0:07:01.680 I probably would interpret that as like, I don't know, 0:07:01.720 --> 0:07:04.120 what's the polite way of putting it, lighting afart kind 0:07:04.160 --> 0:07:04.680 of comment. 0:07:05.040 --> 0:07:08.599 Well, I don't Well, I'm not sure that that was 0:07:08.600 --> 0:07:10.760 the level of excitement, Like it's a bad smell in here, 0:07:10.800 --> 0:07:12.960 let's see if it can busts. It's more like there's 0:07:13.000 --> 0:07:15.480 an unpleasant odor. Let us light a match so that 0:07:15.560 --> 0:07:19.840 the smell of that struck match might mask the stink 0:07:19.840 --> 0:07:20.800 that has enveloped us. 0:07:21.040 --> 0:07:23.640 Yeah, okay, Well, so now I'm understanding several things about 0:07:23.640 --> 0:07:27.560 the world differently than I did before this conversation. But anyway, 0:07:27.720 --> 0:07:29.440 so it makes me think about I see like a 0:07:29.480 --> 0:07:31.880 candle in the bathroom and some matches. Maybe I'm thinking 0:07:32.000 --> 0:07:35.640 about the mechanism differently. It's actually the lighting of the 0:07:35.680 --> 0:07:39.000 match more so than the candle that helps, sort of 0:07:39.080 --> 0:07:42.040 like calm your mind about the smells in there. But anyway, 0:07:42.120 --> 0:07:45.560 the idea is that the sulfur compounds released by striking 0:07:45.600 --> 0:07:51.080 a match overpower other smells in our olfactory recognition. I 0:07:51.120 --> 0:07:53.560 have seen it written in a couple of places that 0:07:53.640 --> 0:07:55.640 the idea is when you strike a match, like it 0:07:55.800 --> 0:07:59.480 burns up the bad gases responsible for causing the smell 0:07:59.520 --> 0:08:01.120 in the air. That does not seem to be true. 0:08:01.160 --> 0:08:03.960 It's more kind of like your your nose and your 0:08:04.000 --> 0:08:07.120 brain are primed to just let the smell of the 0:08:07.120 --> 0:08:09.680 struck match. I think this will be primarily the smell 0:08:09.720 --> 0:08:13.640 of sulfur dioxide. It just take over your smell sensing abilities. 0:08:14.520 --> 0:08:16.600 But it makes me wonder if the burning of hair 0:08:16.720 --> 0:08:19.640 also releases these sulfur compounds that are responsible for the 0:08:19.720 --> 0:08:24.720 characteristic smell, if you could likewise cover up the you know, 0:08:24.760 --> 0:08:27.920 these unpleasant body body aromas, fecal smells and stuff by 0:08:27.960 --> 0:08:28.520 burning hair. 0:08:29.520 --> 0:08:35.360 Well we're not advising that, no, no, but but just 0:08:35.760 --> 0:08:48.440 from like a chemical standpoint, okay, perhaps so. 0:08:48.880 --> 0:08:52.079 One of the most surprising and interesting things I discovered 0:08:52.160 --> 0:08:56.199 by looking into these questions about about the science of 0:08:56.240 --> 0:08:58.680 burning hair was that some of the best research I 0:08:58.679 --> 0:09:02.560 could find on this came from studies about hair catching 0:09:02.600 --> 0:09:04.520 on fire in spaceships. 0:09:05.679 --> 0:09:08.200 Yeah yeah, attack ships on fire off the shoulder of. 0:09:08.200 --> 0:09:11.360 Orion, right, yeah. Yeah. So the main paper I was 0:09:11.360 --> 0:09:14.480 looking at is called the Flammability of Human Hair in 0:09:14.559 --> 0:09:17.920 Exploration atmospheres from the year two thousand and nine in 0:09:18.000 --> 0:09:23.480 the SAE Journal International Journal of Aerospace by Sandra L. Olson, 0:09:23.640 --> 0:09:27.080 Devon W. Griffin, David L. Urban, Gary A. Ruff, and 0:09:27.120 --> 0:09:32.920 Elizabeth A. Smith. And so the authors here begin by 0:09:33.000 --> 0:09:35.400 referencing an older study that I'll mention in a second 0:09:35.640 --> 0:09:39.760 that says, the flammability of both skin and hair has 0:09:39.800 --> 0:09:44.120 actually been a subject of major concern since the early 0:09:44.200 --> 0:09:47.760 stages of the US base program. And they refer back 0:09:47.800 --> 0:09:51.679 to an older paper, one from nineteen sixty eight by 0:09:51.760 --> 0:09:55.840 Robert L. Durfey, called the Flammability of Skin and Hair 0:09:55.880 --> 0:10:00.360 in Oxygen Enriched Atmospheres. This was published in in the 0:10:01.000 --> 0:10:05.280 Or as part of a USAF School of Aerospace Medicine 0:10:05.320 --> 0:10:10.080 technical report. This was from December nineteen sixty eight, and 0:10:10.400 --> 0:10:13.839 durfy begins this study from sixty eight by saying, quote, 0:10:13.880 --> 0:10:18.599 observations after recent fires involving human subjects in oxygen atmospheres 0:10:19.080 --> 0:10:22.280 indicate that the humans may have contributed to the spread 0:10:22.280 --> 0:10:26.160 of fires through combustion of their skin and hair. So 0:10:26.320 --> 0:10:29.800 obviously that's quite morbid. But I was wondering what this 0:10:29.880 --> 0:10:33.800 refers to, and I figured that since this was published 0:10:33.800 --> 0:10:36.520 in nineteen sixty eight. I think it almost certainly must 0:10:36.559 --> 0:10:39.240 be referring, at least in part to the tragedy of 0:10:39.280 --> 0:10:42.720 the Apollo one fire, which killed three astronauts on January 0:10:42.720 --> 0:10:46.720 twenty seventh, nineteen sixty seven. Those astronauts were Gus Grissom, 0:10:46.960 --> 0:10:50.080 Ed White and Roger B. Chaffey, and they died during 0:10:50.120 --> 0:10:52.280 a launch test that was less than a month before 0:10:52.320 --> 0:10:54.880 the scheduled mission, so they weren't actually in space. It 0:10:54.920 --> 0:10:58.200 was a ground test on Earth before the launch of 0:10:58.240 --> 0:11:02.680 an orbital mission. And the tragedy was that a flash 0:11:02.720 --> 0:11:06.240 fire broke out inside the cabin of the command module. 0:11:06.720 --> 0:11:10.040 The fire probably started with There could have been several 0:11:10.080 --> 0:11:12.400 ignition points, but it may have been an electrical arc 0:11:12.520 --> 0:11:17.120 from faulty wiring, maybe connected to some kind of chemical present, 0:11:17.440 --> 0:11:21.240 like a volume of anti freeze fluid called glycol. But 0:11:21.320 --> 0:11:25.080 however it started, it spread very rapidly due to the 0:11:25.240 --> 0:11:29.199 enriched oxygen atmosphere pressurized inside the cabin. It was basically 0:11:29.240 --> 0:11:32.440 pure oxygen in there, and due to a variety of 0:11:32.480 --> 0:11:36.240 combustible materials spread throughout the cabin interior. Now, remember, as 0:11:36.280 --> 0:11:38.600 we've talked about on the show before, fire needs three 0:11:38.600 --> 0:11:41.600 things to burn, it needs heat, it needs fuel, and 0:11:41.640 --> 0:11:45.280 it needs oxygen. Obviously, in this scenario there could have 0:11:45.280 --> 0:11:48.199 been an initial heat source, some kind of ignition point. 0:11:48.640 --> 0:11:51.120 There would have been lots of oxygen because it was 0:11:51.160 --> 0:11:55.800 a pure oxygen atmosphere inside the command module. And so 0:11:55.840 --> 0:11:58.520 the question is what was the fuel and what was 0:11:58.559 --> 0:12:02.280 the fuel roll of very substances, including parts of human 0:12:02.280 --> 0:12:06.000 bodies inside the command module. And so this study was 0:12:06.040 --> 0:12:09.160 looking into human hair and skin, and so one thing 0:12:09.200 --> 0:12:12.360 it says that is that taken as a whole, even 0:12:12.640 --> 0:12:18.520 with enriched oxygen around, human skin is not especially flammable 0:12:19.160 --> 0:12:21.120 because it has a lot of water in it, right, 0:12:21.200 --> 0:12:25.079 So there is a major heat sink in human bodies 0:12:25.600 --> 0:12:29.240 where heat has to be continually applied from the outside 0:12:29.280 --> 0:12:31.040 in order for it to burn. There's a lot of water. 0:12:31.120 --> 0:12:33.480 That water must be turned into water vapor, so it 0:12:33.480 --> 0:12:38.240 doesn't catch fire easily. However, there are sort of little 0:12:38.400 --> 0:12:42.320 layers on the outside of skin and also hair, which 0:12:42.400 --> 0:12:46.520 can catch fire in enriched oxygen environments much more easily. 0:12:47.000 --> 0:12:50.240 This study from sixty eight found that a high concentration 0:12:50.360 --> 0:12:53.320 of inert helium in the air in an environment, in 0:12:53.320 --> 0:12:56.640 this case seventy five percent helium would prevent hair from 0:12:56.679 --> 0:13:00.720 burning at regular atmospheric pressure. And the study also tested 0:13:00.760 --> 0:13:03.560 various protective measures such as smearing the skin and hair 0:13:03.640 --> 0:13:07.800 with protective lotions and greases and covering it with flame 0:13:07.840 --> 0:13:08.720 repellent cloth. 0:13:09.400 --> 0:13:12.600 Was just shaving off all the hair just not an option? 0:13:13.360 --> 0:13:15.160 Seems like if I got to choose between the two 0:13:15.280 --> 0:13:17.280 for my space mission, I would just say, well, can 0:13:17.360 --> 0:13:19.040 we just buzz it all off? 0:13:19.400 --> 0:13:21.120 That is an option that is discussed in the two 0:13:21.120 --> 0:13:23.280 thousand and nine paper, which I'll come back to now. 0:13:23.360 --> 0:13:27.360 So yeah, So initially they cite the Durfy study and 0:13:28.120 --> 0:13:32.120 they say, as a general matter, there are several factors 0:13:32.160 --> 0:13:35.280 to consider that could increase the risk of fires within 0:13:35.400 --> 0:13:39.760 spacecraft or space exploration testing environments. And a big one 0:13:39.760 --> 0:13:41.520 they call out is the same thing we were just 0:13:41.520 --> 0:13:46.720 talking about, elevated oxygen levels. So in some cases ambient 0:13:46.760 --> 0:13:50.840 within spacecraft, but also in cases where supplemental oxygen is 0:13:50.880 --> 0:13:54.360 being provided through a mask. Now, when would there be 0:13:54.440 --> 0:13:58.480 supplemental oxygen inside a spacecraft? You could say possibly in 0:13:58.520 --> 0:14:01.480 a medical intervention for ill or injured crew member. They 0:14:01.559 --> 0:14:05.040 might have extra oxygen supplied to them. This is common 0:14:05.240 --> 0:14:09.040 in hospitals on Earth as well, or possibly during emergencies 0:14:09.080 --> 0:14:12.360 such as the leak of toxic chemicals or in fighting 0:14:12.440 --> 0:14:15.840 a pre existing fire. Now, the authors point out something 0:14:15.880 --> 0:14:19.080 interesting about the case of breathing pure oxygen through a mask. 0:14:19.680 --> 0:14:23.640 They say, quote, for every breath of pure oxygen breathed in, 0:14:23.880 --> 0:14:29.280 the exhaled breath still contains ninety five percent of the oxygen. 0:14:29.720 --> 0:14:33.560 This creates an environment of increased oxygen near the head 0:14:33.640 --> 0:14:37.040 and chest. Now, I did not know that, and don't 0:14:37.080 --> 0:14:39.200 think I would have thought about that before, but from 0:14:39.240 --> 0:14:41.880 what I looked up in other sources, yes, this seems right. 0:14:42.000 --> 0:14:45.880 In breathing say normal air on Earth, which is roughly 0:14:46.120 --> 0:14:50.320 twenty one percent oxygen and the rest is mostly nitrogen. 0:14:51.120 --> 0:14:53.560 In rough terms, that air on Earth. You know, if 0:14:53.600 --> 0:14:57.920 you say twenty percent is oxygen, about fifteen percent of 0:14:57.960 --> 0:15:00.960 the air you breathe out is oc oxygen. So what 0:15:01.040 --> 0:15:04.000 happened to that missing five percent of the air? Well, 0:15:04.240 --> 0:15:07.440 about five percent of the air is oxygen that is 0:15:07.480 --> 0:15:10.080 absorbed by the lungs. So when you breathe in, you 0:15:10.120 --> 0:15:13.000 absorb about five percent of the air, about a quarter 0:15:13.080 --> 0:15:15.640 of the total oxygen content of the air. And then 0:15:15.680 --> 0:15:18.800 that oxygen is replaced mostly with carbon dioxide when you 0:15:18.800 --> 0:15:21.920 breathe out, so that leaves you with what the author said, 0:15:21.960 --> 0:15:24.520 if you're breathing pure oxygen, say through a mask, in 0:15:24.560 --> 0:15:27.400 one of these scenarios, what you breathe out would be 0:15:27.520 --> 0:15:30.760 roughly ninety five percent oxygen, So the area around your 0:15:30.800 --> 0:15:32.720 head as you're exhaling is going to have a lot 0:15:32.760 --> 0:15:36.880 more oxygen in it than it normally would. Now note, 0:15:36.920 --> 0:15:41.160 with regard to ambient oxygen, the oxygen levels used in 0:15:41.240 --> 0:15:46.080 like different space exploration and environments have varied. The International 0:15:46.080 --> 0:15:51.120 Space Station actually maintains roughly the Earth's atmosphere mixture of 0:15:51.200 --> 0:15:54.320 gases in the air, so about twenty one percent oxygen. 0:15:54.360 --> 0:15:58.400 The rest is nitrogen, but the nitrogen has to be 0:15:58.960 --> 0:16:02.640 supplied through through like bringing up tanks of nitrogen to 0:16:03.080 --> 0:16:06.720 make up that difference. So that and other considerations have 0:16:08.240 --> 0:16:10.520 led people to plan that in some other cases there 0:16:10.600 --> 0:16:14.320 might be higher levels of oxygen in the atmosphere breathed 0:16:14.400 --> 0:16:18.560 within space exploration contexts in the future. The authors cite 0:16:18.760 --> 0:16:21.440 a few other examples. They cite past examples as well. 0:16:21.480 --> 0:16:24.160 They say the Apollo missions and sky Lab used higher 0:16:24.240 --> 0:16:28.080 oxygen levels, and as of the time of this paper, 0:16:28.120 --> 0:16:30.320 there were plans for other missions that the authors say 0:16:30.360 --> 0:16:34.520 would have used higher oxygen concentrations. They cite the Orion 0:16:34.640 --> 0:16:39.840 Crew exploration vehicle. They cite the Altai Lander, which would 0:16:39.880 --> 0:16:42.400 have been at the time this mission was planned, would 0:16:42.400 --> 0:16:45.560 have been a landing vehicle for a US mission returning 0:16:45.600 --> 0:16:48.240 to the Moon. And they also talk about higher oxygen 0:16:48.320 --> 0:16:52.200 concentrations in possible lunar surface habitats. So there would be 0:16:52.680 --> 0:16:57.360 numerous scenarios where you're in a space exploration context and 0:16:57.400 --> 0:17:00.960 you would have increased oxygen levels. Either there's just ambiently 0:17:01.000 --> 0:17:04.280 increased oxygen in the particular mission or vehicle you're talking about, 0:17:04.720 --> 0:17:07.239 or you might be needing to give somebody oxygen for 0:17:07.280 --> 0:17:09.720 some reason, in which case there would be in much 0:17:09.760 --> 0:17:13.920 increased oxygen around their head and chest. The authors also 0:17:14.000 --> 0:17:19.080 point out that certain medical interventions could provide ignition points, 0:17:19.119 --> 0:17:22.840 such as you could potentially start a fire during defibrillation, 0:17:23.800 --> 0:17:27.040 and this could happen even on Earth, And I was like, really, yes, 0:17:27.160 --> 0:17:29.760 I went and read about this. It seems to put 0:17:29.840 --> 0:17:32.679 some fears at rest. It is very rare. This is 0:17:32.720 --> 0:17:36.240 not something that commonly happens, but there have been reported cases. 0:17:36.880 --> 0:17:39.960 For example, the following study. I was looking at a 0:17:40.000 --> 0:17:42.919 study published in the Journal of the American College of 0:17:42.920 --> 0:17:46.680 Cardiology by Sanchez at All from the year twenty twenty three. 0:17:47.680 --> 0:17:49.760 It talks about a case where a seventy two year 0:17:49.800 --> 0:17:53.200 old male showed up at the emergency room. He was 0:17:53.240 --> 0:17:59.119 suffering atrial fibrillation, an erratic elevated heart rate, and there 0:17:59.119 --> 0:18:02.399 were several interventions, including the use of a defibrillator to 0:18:02.560 --> 0:18:05.879 stabilize the regular heartbeat. So they put the leads on 0:18:05.920 --> 0:18:08.760 your chest and they send a charge to try to 0:18:09.320 --> 0:18:12.719 synchronize the muscles of the heart. The report says, quote, 0:18:13.040 --> 0:18:18.200 the defibrillator pads ignited in flames after the defibrillation button 0:18:18.320 --> 0:18:21.600 was pressed. The betting and oxygen mask also caught fire. 0:18:21.920 --> 0:18:24.600 Now that's something you don't usually think of happening. However, 0:18:24.720 --> 0:18:27.520 the authors stressed that this is extremely rare. They say 0:18:27.520 --> 0:18:30.119 there are only two known cases in the medical literature 0:18:30.240 --> 0:18:33.840 that they could identify. And also fortunately the patient did 0:18:33.840 --> 0:18:38.600 not suffer actually suffer burn injuries. What was burned appeared 0:18:38.600 --> 0:18:41.760 to be the pads and the patient's body hair in 0:18:41.800 --> 0:18:44.360 some parts of the betting. But they say to avoid 0:18:44.359 --> 0:18:47.359 this happening. There are several steps you can do. Of course, 0:18:47.400 --> 0:18:51.640 the increased oxygen from supplemental oxygen probably contributed here. So 0:18:51.680 --> 0:18:56.240 they say you can remove or place oxygen masks or 0:18:56.359 --> 0:18:59.320 nasal canul of further away from the patient's chest when 0:18:59.359 --> 0:19:03.040 you're doing a defibrillation charge. They say that you can 0:19:03.560 --> 0:19:07.280 prepare the pads better, make sure that they have complete 0:19:07.720 --> 0:19:11.440 attachment to the chest wall. They say chest hair should 0:19:11.480 --> 0:19:14.720 be trimmed ideally, that that helps, and they also say 0:19:14.760 --> 0:19:19.240 avoid alcohol products during the preparation for the defib anyway, 0:19:19.359 --> 0:19:22.560 so that was sort of a tangent. But defibrillation is 0:19:22.680 --> 0:19:25.040 one of the scenarios the author is mentioned that could 0:19:25.080 --> 0:19:29.720 possibly provide an ignition point in space. But coming back 0:19:29.720 --> 0:19:32.480 to the burning hair in space study, the authors also 0:19:32.520 --> 0:19:36.960 mentioned cauterization as a medical procedure that could provide increased 0:19:37.080 --> 0:19:41.399 risk of fire in an oxygen enriched environment. So you 0:19:41.480 --> 0:19:45.119 pair the oxygen ch atmosphere in some spacecraft and space 0:19:45.160 --> 0:19:49.280 exploration environments with various ignitionen scenarios and you've got the 0:19:49.280 --> 0:19:52.719 heat and the oxygen. So the third ingredient is fuel. 0:19:53.000 --> 0:19:55.840 And here the authors point to the presence of potentially 0:19:55.880 --> 0:20:00.800 flammable clothing and hair. Now, in addition to the medical 0:20:00.800 --> 0:20:05.240 ignition scenarios mentioned above, like defibrillation and cauterization, the author 0:20:05.280 --> 0:20:09.120 is note the conclusion of previous research, especially regarding Apollo one, 0:20:09.560 --> 0:20:14.679 that it should basically be considered impossible to eliminate all 0:20:14.880 --> 0:20:18.800 ignition sources in a spacecraft environment. You're always going to 0:20:18.920 --> 0:20:23.439 have things that could generate sparks or electrical arcs or 0:20:23.480 --> 0:20:27.480 hot surfaces. So the best way to limit the risk 0:20:27.560 --> 0:20:31.680 of fire is to control access of those ignition sources 0:20:31.720 --> 0:20:36.280 to fuel by removing combustible materials or making them less combustible. 0:20:36.880 --> 0:20:40.480 You know, I've been watching enough alien movies recently to 0:20:41.240 --> 0:20:43.879 of course know that standard issue. If you're going on 0:20:43.920 --> 0:20:46.280 a space mission, you have a flamethrower on board, you 0:20:46.280 --> 0:20:48.520 have or at least a flame or unit. I don't 0:20:48.520 --> 0:20:51.280 think it's it's necessary. It's not nothing that's supposed to 0:20:51.280 --> 0:20:53.600 be like spitting jelly gasoline or anything like that, Like 0:20:53.640 --> 0:20:56.679 not a military flamethrower, but still a unit that shoots 0:20:56.680 --> 0:20:59.040 a big plume of fire at things. 0:21:00.119 --> 0:21:02.520 Do they have that, that's a good question. Is there 0:21:02.520 --> 0:21:05.520 an industrial use or do they make them? Maybe they 0:21:05.560 --> 0:21:06.440 make them now that. 0:21:06.400 --> 0:21:09.200 I I think sometimes that's the case, But I don't 0:21:09.200 --> 0:21:11.960 know the best I could do putting this together, watching 0:21:12.000 --> 0:21:14.080 the films in the back of my mind, always thinking 0:21:14.160 --> 0:21:17.040 like flame is probably not a great idea in an enclosed, 0:21:17.080 --> 0:21:19.880 sealed environment without even factoring in and all the stuff 0:21:19.880 --> 0:21:23.600 we've been talking about here. But I'm guessing you could 0:21:23.680 --> 0:21:26.479 make a case for Okay, if you are dealing with 0:21:26.520 --> 0:21:30.760 some sort of a life form situa biological threat, like 0:21:30.800 --> 0:21:33.280 some sort of a bug, not a full blown xenomorph, 0:21:33.400 --> 0:21:36.800 you know, but just kind of whatever is expected to occur, 0:21:36.920 --> 0:21:38.520 then I guess you can make a case for a 0:21:38.520 --> 0:21:41.920 flame unit. And then on top of that, if you're 0:21:41.960 --> 0:21:45.399 looking at some sort of a potential like boarding scenario, 0:21:45.720 --> 0:21:47.880 like a boarding action, like people coming on your ship. 0:21:47.880 --> 0:21:50.080 They aren't supposed to be there and you want to 0:21:51.480 --> 0:21:55.359 encourage them to leave or to back off. I guess 0:21:55.359 --> 0:21:57.480 a flame unit you could make some sort of a 0:21:57.480 --> 0:21:59.680 case that a flame unit is better than a gun 0:22:00.080 --> 0:22:03.000 could potentially puncture the whole. But I don't know. Okay, 0:22:03.840 --> 0:22:05.840 once you factor all this in, though, is the risk 0:22:05.880 --> 0:22:07.520 of fire greater. I don't know. 0:22:08.040 --> 0:22:10.080 I think we'll have to assume that, like the Nostromo 0:22:10.280 --> 0:22:14.600 and other alien environments just use they're more like the ISS, 0:22:14.680 --> 0:22:18.160 like they supply the nitrogen, they have a more earth 0:22:18.320 --> 0:22:22.440 like atmosphere rather than the oxygen enriched atmospheres that would 0:22:22.480 --> 0:22:24.160 increase the risk of using flames. 0:22:24.320 --> 0:22:26.520 Sure, Plus everything's a little bit wet on the Nostromo, 0:22:26.640 --> 0:22:28.840 so maybe that helps now. 0:22:28.880 --> 0:22:31.840 The authors of this paper note that a lot of 0:22:31.840 --> 0:22:35.879 individual mission durations are short enough that astronauts don't need 0:22:35.920 --> 0:22:38.160 to cut their hair in space, but even that does 0:22:38.240 --> 0:22:41.919