GE is recalling almost 13,000 MRI units, as the FDA has deemed them potentially deadly.

Some 25 different models, including Signa and Discovery, are affected in the Class I recall.

At certain sites, the magnet rundown unit, or MRU—which is used to squelch the magnetic field in an emergency—“may not be connected to the magnet,” FDA stated in its recall notice. “In emergency situations, a disconnected MRU could delay removal of a ferrous object from the magnet, potentially resulting in life-threatening injuries. The MRU must be connected to the magnet at all times.”

The notice faults not a manufacturing defect or product malfunction but, rather, improper use due to poor training or employee error. It follows a voluntary field corrective action GE issued earlier this month for all its MR systems manufactured with superconducting magnets since 1985.

In a news release announcing the corrective action, GE said it had found that “some MR systems in India have been modified by service personnel or by equipment users to disable the Magnet Rundown Unit.”

The FDA notice shows that more than 7,000 of the affected MRIs are in use outside the U.S.

GE said it is following up with all customers and will correct affected systems at no charge.

FDA’s notice has identifying details on the affected units, along with the how-to’s of a four-part test GE has urged its customers to perform to make sure the MRU is properly connected to the magnet.