It's been a few weeks since our little incident discussed in my [original post](https://www.reddit.com/r/sysadmin/comments/9mk2o7/mri_disabled_every_ios_device_in_facility/).

If you didn't see the original one or don't feel like reading through the massive wall of text, I'll summarize:A new MRI was being installed in one of our multi-practice facilities, during the installation everybody's iphones and apple watches stopped working. The issue only impacted iOS devices. We have plenty of other sensitive equipment out there including desktops, laptops, general healthcare equipment, and a datacenter. None of these devices were effected in any way (as of the writing of this post). There were also a lot of Android phones in the facility at the time, none of which were impacted. Models of iPhones and Apple watches afflicted were iPhone 6 and higher, and Apple Watch series 0 and higher. There was only one iPhone 5 in the building that we know of and it was not impacted in any way. The question at the time was: What occurred that would only cause Apple devices to stop working? There were well over 100 patients in and out of the building during this time, and luckily none of them have reported any issues with their devices.

In this post I'd like to outline a bit of what we learned since we now know the root cause of the problem.I'll start off by saying that it was not some sort of EMP emitted by the MRI. There was a lot of speculation focused around an EMP burst, but nothing of the sort occurred. Based on testing that I did, documentation in Apple's user guide, and a word from the vendor we know that the cause was indeed the Helium. There were a few bright minds in my OP that had mentioned it was most likely the helium and it's interaction with different microelectronics inside of the device. These were not unsubstantiated claims as they had plenty of data to back the claims. I don't know what specific component in the device caused a lock-up, but we know for sure it was the helium. I reached out to Apple and one of the employees in executive relations sent this to me, which is quoted directly from the iPhone and Apple Watch user guide:

>***Explosive and other atmospheric conditions:*** *Charging or using iPhone in any area with a potentially explosive atmosphere, such as areas where the air contains high levels of flammable chemicals, vapors, or particles (such as grain, dust, or metal powders), may be hazardous. Exposing iPhone to environments having high concentrations of industrial chemicals, including near evaporating liquified gasses such as* ***helium***\*, may damage or impair iPhone functionality. Obey all signs and instructions.\*

Source: [Official iPhone User Guide](https://help.apple.com/iphone/12/#/iph301fc905) (Ctril + F, look for "helium")They also go on to mention this:

>*If your device has been affected and shows signs of not powering on, the device can typically be recovered.  Leave the unit unconnected from a charging cable and let it air out for approximately one week.  The helium must fully dissipate from the device, and the device battery should fully discharge in the process.  After a week, plug your device directly into a power adapter and let it charge for up to one hour.  Then the device can be turned on again.*

I'm not incredibly familiar with MRI technology, but I can summarize what transpired leading up to the event. This all happened during the ramping process for the magnet, in which tens of liters of liquid helium are boiled off during the cooling of the super-conducting magnet. It seems that during this process some of the boiled off helium leaked through the venting system and in to the MRI room, which was then circulated throughout the building by the HVAC system. The ramping process took around 5 hours, and near the end of that time was when reports started coming in of dead iphones.

If this wasn't enough, I also decided to conduct a little test. I placed an iPhone 8+ in a sealed bag and filled it with helium. This wasn't incredibly realistic as the original iphones would have been exposed to a much lower concentration, but it still supports the idea that helium can temporarily (or permanently?) disable the device. In the video I leave the display on and running a stopwatch for the duration of the test. Around 8 minutes and 20 seconds in the phone locks up. Nothing crazy really happens. The clock just stops, and nothing else. The display did stay on though. I did learn one thing during this test: The phones that were disabled were probably "on" the entire time, just completely frozen up. The phone I tested remained "on" with the timestamp stuck on the screen. I was off work for the next few days so I wasn't able to periodically check in on it after a few hours, but when I left work the screen was still on and the phone was still locked up. It would not respond to a charge or a hard reset. When I came back to work on Monday the phone battery had died, and I was able to plug it back in and turn it on. The phone nearly had a full charge and recovered much quicker than the other devices. This is because the display was stuck on, so the battery drained much quicker than it would have for the other device. I'm guessing that the users must have had their phones in their pockets or purses when they were disabled, so they appeared to be dead to everybody. You can watch the video [Here](https://youtu.be/5Cvdyt-KZHk)

We did have a few abnormal devices. One iphone had severe service issues after the incident, and some of the apple watches remained on, but the touch screens weren't working (even after several days).

I found the whole situation to be pretty interesting, and I'm glad I was able to find some closure in the end. The helium thing seemed pretty far fetched to me, but it's clear now that it was indeed the culprit. If you have any questions I'd be happy to answer them to the best of my ability. Thank you to everybody to took part in the discussion. I learned a lot throughout this whole ordeal.

​

**Update:** I tested the same iPhone again using much less helium. I inflated the bag mostly with air, and then put a tiny spurt of helium in it. It locked up after about 12 minutes (compared to 8.5 minutes before). I was able to power it off this time, but I could not get it to turn back on.