Superconducting magnets, such as Nuclear Magnetic Resonance (NMR), pose unique safety concerns. These concerns include cryogen safety, strong magnetic fields and the potential for creation of oxygen deficient atmospheres. The highest potential for the most serious of these hazards exists during magnet start-up, cryogen filling and maintenance activities. Once magnets are operational and magnetic fields have been established, the hazards are minimal as long as operators, maintenance personnel, and/or visitors understand the proximity limits and procedures to follow when working near the magnet.
Additional information on magnetic fields can, also, be found on the NIOSH site for EMF (Electric and Magnetic Fields).