Superconducting magnets require safety training for both the use of the magnet and cryogen maintenance.
Specific NMR Safety Instructions are linked here: MagnetSafety
Some examples of accidents in magnet facilities are listed below; in many cases these accidents were caused by individuals who were not properly trained or missing safety equipment. In many cases the person who was not trained actually injured or killed someone else.
Caltech, Pasadena CA – traumatic brain injury: screwdriver stuck on magnet; during the attempt to remove the screwdriver, an object became a projectile and impaled another person, rod entered through the nasal cavity and traveled up into frontal lobe of the brain.
Hoag Hospital, Newport Beach, OC – broken leg and foot, multiple fractures: hospital gurney used to transfer patient was magnetic; patient leg was caught in between magnet and gurney; magnet quenched.
Westchester, NY – death by severe head and brain injury: a 6-year old boy was having an MRI performed; a nurse brought a magnetic oxygen tank into the MRI room; tank became a projectile and crushed the boys skull.
Presbyterian Hospital, NY – death by asphyxiation: MRI technician sent into magnet room without oxygen sensor; leaking liquid nitrogen tank displacing all oxygen in room.
There are many other examples of injuries and accidents; most involve MRI’s – but those instruments have the most traffic; both NMRs and MRIs are subject to the same safety precautions.