A liquid nitrogen burn causes the death of living tissue by extreme cold.
Watch a video about how to fill a hand dewar with liquid nitrogen safely.
Safe Dispensing of Liquid Nitrogen
1. Under no circumstances should you leave the area while filling a dewar.
2. Put on protective clothing.
3. Look for any warning signs or indications that the tank should not be used.
4. Ensure that the tank is more than 20% full. If not, do not fill your dewar.
5. Attach the hose fitting to your dewar or attach the fill-tube (you will need at least one wrench) and place the tube in the dewar.
6. Open the venting valve on your dewar, if applicable.
7. Open the valve on the fill line. (Turn the valve handle counterclockwise.)
8. If filling a wide mouth dewar, keep one hand on the tube and adjust the flow to reduce resonance (whistling).
9. As the dewar is filling, watch and listen for indications that it is nearly full.
10. Close the valve and check the level to avoid overspill.
11. When finished, close the valve (turn the valve handle clockwise) and remove the hose or the fill tube from the dewar.
12. Move your dewar from the filling area back to the lab.