Keep your iPhone away from helium.
Óscar Gutiérrez/CNET
If you're one of those people who actually reads the iPhone user guide, you know there are certain things you should keep your device away from. That apparently includes helium.
"Exposing iPhone to environments having high concentrations of industrial chemicals, including near evaporating liquified gasses such as helium, may damage or impair iPhone functionality," the user guide says.
But for many people, including Reddit user harritaco, this came as a surprise. The Redditor shared earlier this month that after an MRI machine was being installed and tested at his or her workplace, around 40 people's iPhones and Apple Watches stopped working. (Liquid helium is used to cool magnets in MRI machines.) Only iOS devices were impacted. Android users didn't experience any long-term issues, harritaco said.
"It doesn't surprise me that a massive, powerful, super-conducting electromagnet is capable of doing this," the Redditor wrote. "What surprises me is that it is only affecting Apple products."
Another Reddit user, captaincool, wrote that the helium caused the issue because of its impact on microelectromechanical system, or MEMS, oscillators. These are the tiny devices that drive the phone's clock. For the device to work properly, the mechanical resonator has to be kept inside a hermetically sealed chamber, the Redditor explained, but the seals can still be permeable to gasses like helium.
In a Tuesday follow-up to the original post, harritaco said he or she could confirm the cause of the iPhone malfunction was indeed helium. Harritaco conducted some tests, which involved placing an iPhone in a sealed bag with helium. The phone locked up after about eight minutes. This, along with the iPhone user guide and information from the MRI vendor, confirmed the theory on helium being the culprit, harritaco said.
Apple didn't immediately respond to a request for comment.
