This is interesting. I found it completely by accident looking for something else this morning.
OFFICER SAFETY WARNING
Magnetic Resonance Imaging (MRI) Unit Causes
Malfunction of Officer’s Issue Firearm
In July 2001, an officer from the Manheim Township (Lancaster County, Pennsylvania) Police Department had an incident where his issue firearm malfunctioned. The Smith & Wesson, Model 4013, .40 S&W caliber, semi-automatic pistol was found to have a magnetized firing pin, which stuck to the side of the channel within the slide. Upon inspection, it was determined that the entire pistol had become so magnetized that paper clips actually stuck to any metal surface. The department armorer was able to demagnetize the firearm with the use of a high-power, videotape-erasing unit after complete disassembly.
When the malfunction was discovered, the officer had no idea of when or how his pistol had become magnetized. A review of the officer’s activities, revealed that he had investigated a burglar alarm call at a medical office that was equipped with a Magnetic Resonance Imaging (MRI) unit. During the investigation, the officer had walked into the MRI suite that magnetized the pistol. MRI medical personnel have detailed instructions on safety, which include keeping metal objects away from the unit. Upon further inspection, two additional officer’s firearms were also found to have been magnetized.
ALL ISSUE FIREARMS SHOULD BE CHECKED FOR THIS CONDITION
Police department and medical facility security administrative personnel should notify officers of the following:
Investigations within medical facilities could magnetize an issue firearm rendering it inoperable.
The test to determine if a firearm has become magnetized is to place a paper clip next to the firearm.
If the paper clip sticks to the firearm, a supervisor should be notified immediately.
A trained department-designated officer should verify the firearm is magnetized and the firearm should be demagnetized with the use of a high-powered videotape-erasing unit after it has been completely disassembled.
The firearm should be test fired prior to being returned to service.
The fact that there is no outward sign that a firearm may not function as a result of MRI/magnetic exposure makes this problem difficult to detect. Awareness of this situation may prevent serious or deadly consequences.
Source: Sing, Lieutenant Douglas K. Manheim Township (Lancaster County, Pennsylvania) Police Department Revised March 2002.