Philips is recalling hundreds of MRI machines around the globe over concerns the medical imaging equipment could explode during normal operation — something a US Food and Drug Administration (FDA) bulletin states has already happened once before.

The “class one” recall — the most serious type — was published by the FDA online this week, and warns owners of Philips Panorama 1.0T HFO magnetic resonance imagers to discontinue use of the machines until a service technician is able to make corrective repairs.

Sold between 2001 and 2016, the machines are employed broadly by medical facilities around the world to image the inside of patients’ bodies. Today, 150 Panorama 1.0T HFO machines are operating in the United States, and there are reportedly 340 globally.

The recall was issued after it was determined that during a “quench” — when the magnet coils are no longer at near-absolute zero and lose their superconductivity – the helium gas that’s supposed to super-cool the coils evaporates and could cause the device to rupture.