NMR Safety



The hazards of associated with work in the nuclear magnetic resonance (NMR) instrumentation laboratory comes from the high magnetic fields, the handling of cryogens and high electrical voltages/RF sources. Connecticut College uses a Varian Inova 500 NMR, which has a shielded magnet. In general, the NMR hazards can be minimized by limiting access to the NMR facility to only authorized users of the instruments, who have the requisite technical understanding and training.

Electrical Hazards

  • No person may operate the equipment without proper training and authorization from the NMR manager.
  • Extreme caution should be used whenever the instruments are being tuned or otherwise used in a way that makes it necessary to be near the console or magnet.
  • Only authorized and qualified personnel shall access electrical panels or instrument consoles.
  • Report any accumulation of water on the floor of the NMR lab to the NMR manager. Wet areas should be avoided to prevent electrocution.

Cryogenic Liquids (Cryogen Safety page)

  • No person may use cryogenic liquids in the NMR laboratory without first having been trained in the safe handling of such substances.
  • The NMR facility manager must be notified before using cryogenic liquids in the NMR lab.
  • Protective clothing, including lab coats, gloves and eye protection will be worn by all individuals who handle, or are in close proximity when cryogenic liquids are being transferred.
  • In the event of a magnet quench (the sudden evaporation of cryogenic liquids in the magnet), the NMR lab must be immediately evacuated. As the lab is evacuated, the building fire alarm should also be pulled to alert others in the building, especially in basement laboratories.
  • Doors to the laboratory should be left open to aid in the dispersal of helium and nitrogen gases.
  • Any accidental exposure to cryogenic liquids must be reported to the NMR facility manager and the Director of Environmental Health & Safety.

Magnetic Fields and Electromagnetic Radiation

  • Users in the NMR laboratory are subject to exposure to static magnetic fields. Several studies have suggested that long term cumulative exposure to oscillating magnetic fields (60 Hz) may be associated with increased incidence of brain cancer. The cumulative doses for an effect were large, and represented no hazard outside the 5 Gauss line. The radial 5 gauss line for the Varian Inova 500 is 1.3 meters (about 51 inches). All personnel should limit the amount of time spent inside this line.
  • No person may enter the NMR laboratory without authorization from the NMR facility manager.
  • Persons with pacemakers, defibrillators, or metal surgical implants or prosthetics must stay at least 6 feet away from the magnets at all times.
  • Personal articles such as hairpins or jewelry must be kept away from the magnets at all times.
  • Metal tools, carts, and gas cylinders must be kept away from the magnet at all times.

Glass Tubes and Evacuated Storage Dewars

  • NMR Tubes must be handled with extreme caution. They are thin-walled glass and can cause dangerous wounds. Never force an NMR tube into the NMR spinner holder ,and never force the cap on or off an NMR tube.
  • Evacuated storage dewars are present in the probes on all the spectrometers, and are sometimes used externally around spectrometers. These are very dangerous when broken as the vacuum can cause implosion.
  • Always make connections to storage dewars carefully and without force.
  • External storage dewars should always be wrapped in plastic mesh or tape to prevent flying glass if they are broken.
  • Broken glass should be cleaned up and disposed of in approved glass waste containers.
  • All injuries related to broken glass must be reported to the NMR facility manager and the Director of Environmental Health & Safety.

Chemical Hazards

  • NMR Solvents must be handled as specified in the Connecticut College Chemical Hygiene Plan. Because there are no fume hoods in the NMR laboratory, samples requiring a hood for safe handling must be prepared outside of the NMR laboratory.
  • Chemical spills or accidental exposure to NMR solvents must be reported to the NMR facility manager and the Director of Environmental Health & Safety.
  • Material Data Safety Sheets for all chemicals used in Hale Laboratory can be found in the online CEMS Chemical Inventory Management System.

Physical Hazards

  • To prevent falls, stepladders and footstools, must be used with caution.
  • Care must be taken to avoid overturning of the magnets. No person should ever lean on the magnet or pull on the magnet when climbing up or down when tuning the magnet.
  • Cryogenic storage dewars can also be overturned quite easily. They should never be pulled from the top, but rather from the handles provided.
  • All injuries related to physical hazards in the NMR laboratory must be
    reported to the NMR facility manager and the Director of Environmental Health & Safety.