13 ms·
I feel like the buried lede is that the MRI operators vented large quantities of helium into the hospital's HVAC and didn't think to tell anyone.
by gok 8y ago
I feel like the buried lede is that the MRI operators vented large quantities of helium into the hospital's HVAC and didn't think to tell anyone.
- jedberg 8y agoThey thought they were venting outside. It only went inside because of an undetected leak.
- deleted 8y ago[deleted]
- GhostVII 8y agoYea, that sounds incredibly dangerous considering how easily you can suffocate inhaling helium
- knodi123 8y agohow easy is it? It floats, so it only fills a room from the top down... and if you fall over unconscious, you're automatically moving to a part of the room with more oxygen. it would have to displace all of the air in a room in order to suffocate someone, no?
- JumpCrisscross 8y agoMulti-story building. The floor could be, given enough gas, under.
- sebazzz 8y agoIf helium is small enough to get in a watertight phone, it is certainly small enough to dissipate in a probably not so watertight building.
- JumpCrisscross 8y agoQuenching MRI magnets can suffocate people in the room they quench, and potentially the entire floor. I don’t know about a whole building, but just because something can dissipate doesn’t mean it can’t do damage in the meantime.
- warrenm 8y agoNot true - the whole point of burst discs etc in MRIs is so that if a quench happens, the patients and any technicians in the room survive Venting even a full MRI's worth of LHe (~1500l) as most will make you a little lightheaded for a few minutes The risk of death from quench events is effectively non-existent
- dx87 8y agoIf you fall over unconscious from helium then you'll probably die without immediate help. Your natural breathing reflex is triggered by the presence of CO2, not the lack of oxygen. If you inhale a lot of helium and pass out, your body doesn't start breathing again because there is no CO2, so you just suffocate instead of inhaling oxygen.
- ddalex 8y agoyou don't breathe because there is CO2 in the air, you breathe because there is CO2 in your blood
- mrob 8y agoYou're continuously producing CO2 whenever you're alive. If you fall down and land in a normal atmosphere then your normal breathing reflex will save you. Low oxygen atmospheres don't stop you from breathing; they're dangerous because you continue breathing as normal. The CO2 is carried away from your lungs with each breath, so there's no feeling of suffocation.
- godelski 8y agoWell helium rises. So falling down is a good thing, as most vents are above you. If you go to a lab with heavy gases you'll notice vents on the floor for exactly this reason.
- outworlder 8y ago> If you inhale a lot of helium and pass out, your body doesn't start breathing again because there is no CO2, so you just suffocate instead of inhaling oxygen. Other posters have pointed out that this is false(you will continue producing CO2 while unconscious just fine, chemoreceptors will notice). I would like to add that I have personally witnessed people falling unconscious from helium. They recovered just fine. Really, the greatest danger is the fall.
- bodas 8y agoIf that were true then divers would have to bring canisters of CO2 down with them.
- GhostVII 8y agoI meant more that you don't feel like you are suffocating when you are inhaling helium, so it can be hard to realize something is going wrong until it is too late. Definitely easier to suffocate with heavier-than-air gasses though.
- godelski 8y agoIt's fairly difficult, but definitely possible. It's hard to recognize because what is killing you is the lack of oxygen. People generally don't notice they are becoming hypoxic. But there are plenty of things to help you out here. First is that helium is very light. So if you pass out and fall down you will be in a lower concentration of helium (assuming you are not in a sealed room). (Labs with heavy gases have vents on the floor) If the room is reasonable ventilated you should be fine. It dissipates fairly quickly. Helium permeates through most things, but this is a slow process so probably won't save you.
- varenc 8y agoOxygen monitors are standard practice when you have MRI machines and Helium cooling. I would like to assume that this monitoring was in place and it never raised any flags? https://www.pureairemonitoring.com/helium-mri-rooms-around-world/ https://www.pureairemonitoring.com/helium-mri-rooms-around-w... The air’s usual O2 concentration is ~20.5% and it looks like safety monitors trigger at 19.5% and 18%: https://www.pureairemonitoring.com/all-categories-gas-monitorsair-check-o2-oxygen-deficiency-monitor-for-co2-n2-storage-areas/ https://www.pureairemonitoring.com/all-categories-gas-monito... Helium makes up less than 0.0005% of air naturally. I’m guessing that increasing He concentration 1000 times to 0.5%, for example, is enough to cause problems for iPhones, but not enough to trigger the alarm or pose any danger to people.
- deleted 8y ago[deleted]
- Novashi 8y agoOr the O2 alarms just don't work and the hospital was negligent.
- na85 8y agoOccam's razor.
- gotocake 8y agoNot enough to directly endanger people, but a hospital is full of electronics that plenty of people need to live, and it sounds like they could potentially share the iPhone’s vulnerability.
- rpcastagna 8y agoIf it makes you feel better: Hospitals of reasonable size typically have an on-site clinical engineering team that handles those kinds of situations. Important (that is, capital expense category) hospital equipment will typically emit all kinds of warnings and alarms way before anything's actually a problem, because everyone would rather rely on the on-site engineering spending a little extra time silencing false positives then leave anything to chance.
- kens 8y agoAnother scary practice is venting natural gas indoors. Most of the time it's fine, but sometimes you get a catastrophic explosion: https://www.youtube.com/watch?v=rjxBtwl8-Tc https://www.youtube.com/watch?v=rjxBtwl8-Tc (The US Chemical Safety Board has a bunch of interesting videos.)
- adetrest 8y agoThis is nuts! Why would you even vent flammable gases indoors on a construction site?!
- MertsA 8y agoBecause when you initially pressurize a newly installed portion of pipe, it's not filled with natural gas, it's filled with air. Air doesn't burn, something like a natural gas burner with a pilot light is going to detect that the pilot light went out and shut off the gas flow to prevent an explosion. That leads to a sort of catch 22, you can't purge the line without the burner going and the burner won't turn on until the line is purged. Ideally you would pressure test and purge new work with nitrogen as well in order to prevent a potentially combustible mixture from forming inside the pipe while the air is being purged from it. As to the safety of purging natural gas directly indoors, obviously that carries some risk but it's not as dangerous as you might assume. Below a certain concentration (5% by volume) natural gas mixed with air actually won't burn freely. Also above 15% natural gas by volume won't burn freely. The risk of an explosion is only present in that 10% range. If you're putting in a new gas stove in your kitchen and you crack open the valve with the hose off of the stove until you smell gas, that's not a ton of natural gas that you've let out into a room with a relatively huge volume. The pressure of a natural gas pipe in a house is actually very low, only around 0.25 psi. It's coming out slow enough that you've got plenty of time to turn off the gas before you come anywhere close to hitting that lower explosion limit where things get extremely dangerous.
- CodeWriter23 8y agoWouldn't this affect people's voices?
- outworlder 8y agoEventually. But I would expect that by the time the effect is noticeable, the concentrations will be too high to support consciousness and will have been for some time.
- teraflop 8y agoI'm not sure that's true. If you displace 30% of the atmosphere with helium, the O2 concentration drops from 21% to 15%. That's low enough that you'll probably start to see mild cognitive impairment, but it's still plenty capable of supporting life. However, a 30/70 mixture of helium and air is about 67% as dense as normal air, which means voices would be pitched more than half an octave higher.
- lurquer 8y agoIndeed. I had to reread that paragraph. That's a LOT of helium (by volume). "So, i noticed some of the workers' iwatch's weren't registering the users' heart-rates. At first, I thought it was because they had all died from suffocation from the massive gas leak. But, then I discovered something interesting... it was actually the helium molecules worming their way into the internal clock chip! Amazing day."
- therein 8y agoWhat a relief that must have been.
- SilasX 8y agoYeah, but at the same time, it wasn't enough to set off the alarms for low oxygen content, which is at least a little disturbing, right?
- pjscott 8y agoAs long as there is enough oxygen in the air, what's disturbing about it? People breathe helium/nitrogen/oxygen mixtures all the time. https://en.wikipedia.org/wiki/Trimix_(breathing_gas) https://en.wikipedia.org/wiki/Trimix_(breathing_gas)
- SilasX 8y agoI didn't mean that the air would be dangerous to breathe. I meant that it's disturbing that the amount of He needed to disable the iPhone is low enough that the standard sensors around He (which measure 02 levels) don't regard it as a major leak for He to be at that level.
- jakevn 8y agoWhy would that be disturbing? Electronics and organisms do not have identical environmental tolerances/intolerances. Presumably, the sensors exist to protect humans, not electronics.
- nvahalik 8y agoAs long as he helium doesn’t displace the oxygen it is fine. Saturation diving has people living in “heliox” environments where the atmosphere is helium and oxygen.
- kabacha 8y agoExcept that Helium is not dangerous whatsoever and to actually displace oxygen you would need much much more than that.
- nradov 8y agoConsidering the current helium shortage it's a shame they just wasted it.
- Arn_Thor 8y agoRight! It's not like an "allergy" to helium is going to be a problem for any user at any time unless, you know, there's a big helium leak, at which point the phone is the least of your problems
- dirkt 8y agoThere are more details in the original thread https://www.reddit.com/r/sysadmin/comments/9mk2o7/mri_disabled_every_ios_device_in_facility/ https://www.reddit.com/r/sysadmin/comments/9mk2o7/mri_disabl... on reddit: I discovered that the helium leakage occurred while the new magnet was being ramped. Approximately 120 liters of liquid He were vented over the course of 5 hours. There was a vent in place that was functioning, but there must have been a leak. The MRI room is not on an isolated HVAC loop, so it shares air with most or all of the facility. We do not know how much of the 120 liters ended up going outdoors and how much ended up inside.
- warrenm 8y agoVenting 120l of liquid helium (or about 84,000l of gaseous helium) really isn't that much of a health concern I've seen multiple vents of ~1500l of liquid helium (~1,050,000l of gaseous) in a single day from a couple bad MRI units when I worked at a company that makes them Only "dangerous" place to be was in the fragmentation path of the burst disc (which was enclosed in the top of the unit (at the time)), or directly in the path of the nearly-liquid (ie extremely cold) helium as it vented It dissipates extremely rapidly