iPhones Have a Helium Allergy: The Strange Case of Apple Devices Failing Near MRI Machines

This is not a story you hear every day. Eric Wooldridge, a complex systems specialist at Morris Hospital near Chicago, was installing a new MRI machine from GE Healthcare when he started receiving complaints about non-functioning phones. Soon after, people also reported issues with their Apple Watches.

“My first thought was that the MRI was emitting some kind of electromagnetic radiation that could cause all sorts of problems,” Eric said. But if it were an EM pulse, it would have also knocked out the hospital’s medical equipment—yet everything else was working perfectly! Investigating further, he discovered that every affected device was made by Apple, while his own Android phone worked just fine. The incident was widespread, impacting about 40 different devices. What was going on?

Eric had seen plenty of strange glitches in his career, but nothing like this. “The devices were acting weird. Most were completely dead. I’d plug them in, but there was no sign of charging. Others would turn on, but had issues with cellular signal. WiFi worked fine, but cell service was spotty.”

He posted about the problem on Reddit, and other system admins speculated that the culprit could be liquid helium used to cool the MRI. Eric investigated and found a helium leak that had spread throughout the building.

How Helium Leaks Can Affect Electronics

“I found that the helium leak happened while the new magnet was being cooled. About 120 liters of liquid helium escaped over five hours. The machine’s valve was working, but probably leaking. The MRI room wasn’t isolated from the building’s ventilation, so the air mixed with the rest of the hospital. We don’t know how much helium escaped outside versus inside. As helium turns from liquid to gas, it expands 750 times, so we ended up with a huge amount of helium (about 90,000 liters) in the building.” Eric joked, “I bet the nurses’ voices were higher that day!”

After the initial incident, devices slowly started to recover, but not completely. “Some devices were still acting up. One phone had serious repair issues, and some smartwatches kept having touchscreen problems even days later.”

Eric sorted the devices by type. “iPhones version 6 and up, and Apple Watches version 0 and up were affected. We know there was one iPhone 5 in the building that day, and it was fine. So what happened that only Apple devices broke?”

Why Only Apple Devices?

This piqued my interest, so I reached out to friends in the microelectromechanical systems (MEMS) industry. These are some of the smallest mechanical devices in the world. Every phone has gyroscopes and accelerometers with components just micrometers thick. My first theory (which matched a Reddit user’s) was that helium molecules, being so small, got inside these chips and interfered with their mechanical parts.

But there are two problems with this idea: First, Apple isn’t the only company using MEMS gyroscopes—they’re in many phones. Why weren’t Android phones affected? Maybe there’s a bug in iOS that causes a system failure when it gets bad data from the gyroscope? But the issue also affected Apple Watches, which run their own OS, WatchOS. Plus, iPhones older than version 6 weren’t affected. It’s unlikely this was a new software bug affecting both iOS and WatchOS at the same time.

The Real Culprit: MEMS Oscillators

At the heart of every electronic device is a clock, usually a quartz oscillator—a crystal vibrating at a predictable frequency, typically 32 kHz. When first invented, these allowed for the creation of quartz watches. Now, these frequency generators are in every electronic device. Without a clock, the system freezes. The CPU won’t work. The clock is the heartbeat of modern devices.

But quartz oscillators have issues: they don’t keep time well at extreme temperatures and are relatively large (about 1×3 mm). In the quest for smaller devices, Apple recently started using MEMS oscillators from SiTime to replace quartz components.

Specifically, they use the SiT512, “the world’s smallest and lowest-power 32 kHz oscillator.” If any MEMS device is vulnerable to helium, this could be the culprit!

Testing the Theory: Helium Stops the Clock

The symptoms of a failed oscillator matched what Eric described, and he was able to reproduce the issue in an experiment. “I put an iPhone 8 Plus in a sealed bag and filled it with helium. This wasn’t exactly the same as the hospital incident, since those iPhones were exposed to lower concentrations, but the experiment still supports the idea that helium can disable a device. I left the display on and started a timer. After 8 minutes and 20 seconds, the phone froze. Nothing dramatic happened—the clock just stopped, and that was it. The screen stayed on.”

I was able to repeat the experiment in our lab. My iPhone 8 lasted about 4 minutes in a helium atmosphere before shutting down completely.

Apple’s Official Warning

Apple’s user manual for iPhones and Watches mentions a similar problem:

Do not expose your iPhone to environments containing high concentrations of industrial chemicals, including evaporating liquefied gases like helium—this can damage or impair your phone’s operation. If your device has been exposed and shows these symptoms or won’t turn on, it can usually be recovered. Leave it unplugged and let it air out for a week. The helium should fully dissipate, and the battery should completely discharge. After a week, plug the device directly into a charger and let it charge for an hour. Then you can turn it on again.

Why Helium Is So Hard to Contain

Hydrogen and helium are extremely difficult to contain because their molecules are so small. SiTime has been working on this issue for a while. In their FAQ, I found:

How effective is the hermetic seal of MEMS oscillators? Previous generations of EpiSeal resonators could be affected by high concentrations of small-molecule gases. Newer EpiSeal generations are impervious to all small-molecule gases. Contact SiTime if you plan to use our device near high concentrations of small-molecule gases so we can recommend the right part.

I wondered if helium would affect other types of MEMS devices, so I contacted InvenSense Motion, which makes the image stabilization chip for the Pixel 3. David Almoslino, Senior Director of Corporate Marketing, confirmed the issue. He told me their products “can be somewhat susceptible to helium. Helium can seep through fused substrates and increase pressure in cavities. Helium can temporarily degrade the absolute accuracy of our pressure sensors. In gyroscopes, helium can cause imbalance, temporarily stopping oscillations. In accelerometers, helium doesn’t do much harm. But all our products should recover after being removed from a helium-rich environment.”

Of course, you’ve probably never heard of this before because such situations are extremely rare. But silicon chip manufacturers are well aware of the problem and do everything they can to minimize it. David told me, “Helium leak testing is a standard MEMS test that most companies use to check for hermeticity.”

The Bottom Line

That’s the story! Helium molecules, like incredibly tiny grains of sand, can get inside your device, stop its clock, and temporarily turn your phone into a paperweight.