The iPhone Is Apparently Allergic to Helium

Helium. It’s not a gas you probably pay much attention to, unless you work in a handful of very specific industries, enjoy playing with insane overclocking rigs, or have a job filling party balloons. But helium is critical in the cryogenics industry, which means it’s used in hospital MRI scanners to keep the superconducting magnets operating at the necessary temperature. That fact has led to the discovery of a rather odd issue with Apple iPhones — they can shut down when exposed to helium, sometimes for days at a time.

A long Reddit thread by Systems Specialist Erik Woolridge and subsequent iFixit write-up lays out the story. During the installation of a new MRI machine at Morris Hospital near Chicago, calls started coming in to IT reporting that Apple iPhones had stopped working. iPhones above the iPhone 6 and Apple Watches were both impacted (the single iPhone 5 in the building was not). Apple’s official user guide for the iPhone actually mentions this. Apparently, the official Apple fix is as follows:

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.

We say “apparently” because we can’t actually find that statement on any Apple guidance, despite the fact that both the original Reddit post and the iFixit story link to the same page of the Apple guide and quote it. Either this guidance has been removed or is located in a different section of the site (we’ve reached out to the original Reddit author to confirm that the company has changed its site). Unfortunately, the Wayback Machine did not archive the page.

During his investigation of the issue, Wooldridge discovered that a helium leak had indeed occurred inside the hospital and that it seemed to be responsible for the iPhone failures, with more than 40 devices impacted in total. And according to iFixit, the most likely culprit for this problem is the miniaturized clock circuit Apple uses in its devices. Instead of relying on an old-fashioned quartz oscillator, Apple uses a Micro-Electro-Mechanical-System or MEMS silicon solution with a miniaturized clock oscillator instead of a more traditional chip — and iFixit’s investigation confirmed both that iPhones stop responding when exposed to helium and that this is a known issue for MEMS silicon in general.

MEMS devices can be susceptible to helium, a senior marketing director for InvenSense Motion, a MEMS company that builds silicon for the Pixel 3, told iFixit:

Helium can diffuse through the fusion bond oxide and cause the cavity pressure to increase. In our pressure sensors, helium could cause the absolute accuracy to temporarily degrade. In our gyro sensors, helium could cause the offset to drift and could cause the oscillation to temporarily stop. In any [accelerometer] sensors, helium should have very little impact. All our InvenSense parts should recover once removed from any helium environment.

In this case, the helium is obviously interfering with some fundamental function of the clock generator. Obviously, the practical impact of this bug on most people is nil. But it’s an interesting example of how small glitches can expose weaknesses in device design that you’d never even think to look for as a consumer. Trace amounts of helium normally wouldn’t be considered an issue for electronic hardware — but the wrong combination of events can lead to devices shutting off and refusing to work for days or even a week.