I am a police officer and at work we recently were told of a potential problem. It came down to us through official channels from the state. When I heard it it seemed like an Urban Legend and I wasn’t the only one who thought so. The email stated that in some police department officers entered a doctors office that contained a MRI. Somehow the MRI magnetized their guns and rendered them inoperable without them knowing it. It sounded like BS to me. I couldn’t find anything about it on Snopes. I am not an expert on the manufacture of guns but from what I do know it seems unlikely. We have Glocks. The lower receiver is plastic so interference with the slide is not an issue. Can the firing pin be magnetized so it won’t move? Can the slide become so magnetized by a MRI that it won’t move? Would it become magnetized at all? I would love to be able to post a cite on our bulletin board with the truth about this. Please try to keep the “I don’t think so” posts to a minimum, thats were I am now. Facts please (unless your post is otherwise interesting, then fire away).
Apparently, it actually happened, on at least one occassion. In this case:
Degaussing would be simple enough, since the sort of steels used are fairly low coercivity–that is, it doesn’t take a very strong field to magnetize or demagnetize them. In the above case, a videotape degausser was used, but a TV/monitor degaussing coil would also work quite well.
Beaten on preview, but there is also this incident
An MRI site (also from Rochester) makes an additional comment:
My skepti-sense is tingling on the latter “cites”. Think about it-if the magnetic pull were sufficient to take the weapon out of the officer’s grasp, what became of the other metallic objects on his person? Ballpoint pen, uniform and personal jewelry, baton lazy ring, belt buckle, spare clip(s), portable radio, flashlight, etc. Uniformed officers drag a lot of stuff around, and from the sound of those quotes, an MRI would pull him across the room. No offense meant Exapno Mapcase, but I’m feeling :dubious:
Well, first, not all metal items are attracted by magnets. MagLite flashlights have aluminum cases; ammunition is brass and lead; none of these metals are attracted to magnets. Jewelery that’s attracted by magnets would have to be really cheap stuff.
Second, not all the items you mention would necessarily be metal. Most ballpoint pens are plastic nowadays.
Third, even if 20 metal items on your person are pulled into an MRI, if one of them is a gun, you’re going to be a damn sight more worried about the one gun than the 19 other items, and they may not make it into your report on the matter.
I’m not skeptical about this report, as you can guess. I’ve known people who worked with research MRIs, and read case reports of what can happen with the medical ones. I’ve heard of a janitor taking a floor buffer into an MRI room and seeing it fly across the room and slam into the machine hard enough to dent it badly. I’ve read of a patient hit in the head by an infusion pump that flew off the gurney into the MRI machine. Incidents of the latter sort are common enough that MRI-compatible pumps and other machinery have been designed since the machines became popular. Those magnets are ferocious.
People have been pulled off their feet and into the “donut hole” in an MRI by the magnetics acting on items they are wearing. One of the nastiest cases I heard about was a firefighter who’s air bottle got “grabbed” by an MRI and both it and he were pulled into the machine. He was so doubled over and compressed by being jammed in there that there was concern he’d suffocate. They eventually had to turn off the machine, demagnitize it, and partially disassemble it to get him out. The man suffered back and torso injuries as a result.
MRIs can be quite dangerous.
Here are the original stories from the Rochester Democrat & Chronicle, although the full stories are blocked behind a payment wall.
Seems legit to me.
Observe: DANGER! Flying Objects!
Wow! I didn’t know tigers were magnetic! 
I had to setup some computer systems around an MRI lab once and needless to say the presence of such a magnet had us all a bit concerned (not that we thought we’d be close enough to have the machines fly across the room but that the field would be strong enough to wreak havoc on the computers). I do not know if all hospitals do this but in our case they had a map (looked kind of like a topographical map) that showed the magnetic strength at various distances from the machine. One line was marked as the point of no return for your credit cards (which they actually marked on the floor with a painted line).
Thank you for further info, all.
Having worked for a company tha serviced these magnets by supplying them with liquid helium, I can say that these sorts of events do happen from time to time. Oxygen tanks needed for patients in an MRI need to be aluminum, not the ordinary steel E cylinders. Occasionally a mistake is made, resulting in a steel oxygen tank being pulled into the magnet, often causing significant damage to the unit.
Thanks for the cites. The only thing that rings false with me is the report of the gun being yanked out of the holster. Weapons retention holsters are the norm. There is usually a manual release or two that need to be manipulated in order to get the gun out of the holster. I could see it being pulled out of someones hand but not the holster.
Funny, but this exact phenomenon was a plot point in a recent CSI episode. It seemed a little far-fetched to me, but my knowledge of MRIs is limited to what they do and a bit of how they do it, so I didn’t know enough to determine the effects of just walking by one in operation.
I didn’t realize the magnetic field on those things was that strong – but the I guess given their size, there’s a reason the examiners are sheilded in another room during the process.
My brother repairs MRIs, and he’s told me some stories. Even some things that contain no iron are affected. He showed me an aluminum sign, then he stood it upright inside the magnet. When he let go, it very slowly fell to horizontal.
He said, even though he knew better, he has forgotten and killed a few watches and credit cards.
This is due to the motion inducing eddy currents in the conductive metal that in turn generate fields that oppose the motion. It’s called magnetic damping. If you take a small cylindrical rare-earth magnet, and drop it through a copper tube, the effect will be very obvious.
In the case of the gun being pulled from the holster, it is not inconcievable that the officer had his hand on the gun, and deactivated the retention device, as the cite stated he was investigating a burgaler alarm. I have certainly observed this in routine traffic stops…gun not drawn, but hand on gun with thumb strap unsnapped.
At one company where I worked, a couple of cow-orkers had “liberated” one of those St.Pauly Girl life-sized cutouts you see in bars and it became the department mascot. One night somebody left the front door unlocked, the wind set of the alarm, and cops showed up. The next day one came by and suggested that we either be more careful about locking up or get rid of “that F’ing girl”, as it had scared the hell out of him, and he said he definatly did draw on it.
Although you can still get holsters with just a strap that is not what I mean by a weapons retention holster. Though it is not impossible for a police officer to have such a simple holster it is not likely. I’ve had holsters that you have to push back and out on the gun while releasing the strap at the same time. I have had holsters that you had to push down and forward on the strap while pushing down on a button on the side before removing the gun. It’s supposed to keep someone else from removing it while you are rolling around on the ground with them. It should keep a MRI from doing the same.
Just here to say that yes, I work in a radiology clinic with an MRI, and my administrator told me it will pull steel oxygen tanks across the room. We have a sign up prohibiting them, but ambulance crews don’t always remember. Our MRI has been damaged twice as a result of steel oxy tanks.
I wonder why MRI rooms don’t have ferromagnetic metal detectors at the entrance? Seems like this kind of thing happens with surprising regularity, and given that an MRI machine costs more than my house it seems only prudent to have minimal technology in place to prevent this kind of accident.
And I wonder how those detectors would be influenced by the MRI. I suppose you could put it far enough away, but that might take up a largish amount of space around the magnetized area. Probably not always practical.
Most areas where an MRI is located are posted to prohibit bringing any metallic object into the proximity of the MRI machine. It uses a very intense magnetic field (don’t recall the intensity) which could rip the gun out of it’s holster or your hand, make lethal projectiles out of O2 tanks, and other assorted disasters. It could possibly magnetize gun components to make it’s operation erratic or to malfunction.
IOW Beware of the MRI!