SafetyPhysics

Liquid Nitrogen Accident
UNSW School of Physics, May 2003




  In May 2003 there was an accident in the School of Physics during decanting of LN2 from the bulk storage tank into a small dewar.

The person received burns to the back of the right hand as shown. The injuries prevented the person from using their right hand for 10 days (writing, holding a book, eating, etc).

Injury

The principal cause of the INJURY was liquid nitrogen caught in the glove from severe splashing. The glove was not inside the sleeve of the coat.

The person remembers that there was no immediate pain to the hand, only a sensation of numbness rather then coldness. An eyewitness estimates the duration of the exposure at 30 seconds only. The injury was then flushed with cold water for 20 minutes.

Accident

The contributing factors to the ACCIDENT included:

  • Crowded work area (another person's large dewar was in the way)
  • Over-stretching to get around large dewar
  • Turning the control valve for LN2 the wrong way
  • Swapping hands for operating valve for LN2

An analysis of this accident suggests all users REMEMBER:

  • Wear gloves inside coat sleeves to prevent LN2 entering gloves.
  • Know which way to turn the control valve to stop the flow of LN2.
  • Have a clear workplace: Remove unnecessary dewars and equipment.
  • Know where the cold-water tap is located inside the LN2 compound.

First Aid

The first step in First Aid is flushing the injury with cold water.

Investigation

The school commenced an OHS investigation into the accident. The report and recommendations are available to the staff and students through the OHS committee.


Further discussion about preventing cryogenic injuries can be arranged through Pat McMillan (x54543), Jon Everett (x56300)