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Student Sustains Cold Burns When Retrieving vial from Liquid Nitrogen

What Happened?

A principal investigator (PI) was instructing an undergraduate student working in his lab on how to transfer cryovials from a liquid nitrogen dewar to a -80 freezer. During the procedure, a cryovial dislodged from the rack containing the cryovials into the liquid nitrogen. The PI placed the rest of the cryovials into the -80 freezer and asked the student to recover the dislodged cryovial floating in the liquid nitrogen. The student, who was wearing cryogenic gloves over nitrile gloves at the time, grabbed the vial directly out of the liquid nitrogen. The student indicated to the PI that he felt a burning sensation but did not see any visible cold burns. A few hours later, the student noticed blistering on his fingers and sought medical attention. The student reported the incident to his PI, who send the student to report to the Occupational Health Facility for further evaluation.

What Was The Cause?

The cryogenic gloves worn by the researcher appeared to be intact. Cryogenic gloves are meant to handle cold items and protect to temperatures as low as -162°C (-260°F). However, they are not meant to be submerged into liquid nitrogen which has a temperature of −196 °C ( −321 °F). In addition, if the gloves were used for other purposes where they get wet, the problem can be compounded. Not all cryogenic gloves are water-resistant.

What Corrective Actions Were Taken?

  • The correct use of cryogenic gloves was reviewed with all lab members
  • A standard operating procedure (SOP) was developed for handling liquid nitrogen 
  • All lab members were briefed on the new SOP 
  • Forceps were made available to retrieve items from liquid nitrogen

How Can Incidents Like This Be Prevented?

  • Use forceps or tongs to remove items from liquid nitrogen; never touch liquid nitrogen directly 
  • Be aware of the limitations of cryogenic gloves

Resources

 

QUICK ACTION TIPS 

Contact with cryogenic materials can rapidly freeze and destroy skin tissues. If exposed:

  1. Remove all clothing that may restrict circulation to the frozen area
  2. Flush affected area with tepid, not hot, water. The water temperature should be barely above body temperature; do not use dry heat
  3. Do not rub frozen body parts, before or after warming
  4. Cover thawed body part with dry sterile gauze and large, bulky protective clothing
  5. Contact medical attention
  6. Report the incident to your supervisor

 

Liquid Nitrogen

  • Liquid nitrogen cold vapors can cause cryogenic burns and tissue damage to the eye
  • Liquid-to-gas expansion ratio of nitrogen is ~700:1 at 20 °C (68 °F), which can generate great force
  • Might act as an asphyxiant in confined spaces