Here’s an NMR imaging blog with details of a recent problem in an Indian facility. Two people ended up stuck to the machine, pinned by an oxygen cylinder (!) that one of them brought into the room. Both sustained injuries.
There are two questions here: one is how anyone is allowed to wheel a ferromagnetic metal cylinder anywhere near an NMR magnet, and the other is how it took so long to quench the magnet once the accident had occurred. That latter point is addressed by the blog link above – the hospital is saying that the emergency quench circuit malfunctioned, and that it took four hours for a GE technician to arrive and get things shut down. I’m no NMR hardware expert, but I wonder about that one myself. As that blog post concludes:
Whether or not GE was really at fault in Mumbai we shall learn eventually, I hope. (I have heard rumors that some sites like to bypass their quench circuit in order to avoid having the cost of recharging the magnet should the quench button get activated. Insert your own exclamations of disbelief here because I’m incredulous.) In the mean time, this sorry saga is an opportunity for all of us to review our own procedures and take the extra moments to ensure that we’ve done everything humanely possible to eliminate risks. There really is no excuse.