Leave the NMR room immediately in the incident of a magnet quench.
If the magnet should quench (sudden appearance of gasses from the top of the Dewar), leave the area immediately. Sudden release of helium or nitrogen gases can rapidly displace oxygen in an enclosed space creating a possibility of asphyxiation. Helium will displace air from the top of a room and cold nitrogen can displace air from the lower levels of a room.
Do not exceed the boiling or freezing point of a sample during variable temperature experiments.
A sample tube subjected to a change in temperature can build up excessive pressure, which can break the sample tube glass and cause injury by flying glass and toxic materials. To avoid this hazard, establish the freezing and boiling point of a sample before doing a variable temperature experiment.
Do not locate your hands on the magnet
The magnet Dewar has a high center of gravity and supported with the antivibration legs bolted to the floor. And the magnet can be easily tip over if you locate your hands on it while inserting sample into magnet.
Keep magnetic media, ATM and credit cards, and watches outside the 5-gauss perimeter from the centerline of the magnet.
The strong magnetic field surrounding a superconducting magnet can erase magnetic media such as floppy disks and tapes. The field can also damage the strip of magnetic media found on credit cards, automatic teller machine (ATM) cards, and similar plastic cards. Many wrist and pocket watches are also susceptible to damage from intense magnetism.