Liquid Nitrogen Safety
Research Safety
Liquid nitrogen safe handling and use
Liquid nitrogen is commonly used in laboratories for cryogenic storage, cooling and specialized experimental applications. It is a colorless, odorless, inert and non-toxic cryogenic liquid, with a boiling point of -320°F (-196°C).
Asphyxiation Hazard
Liquid nitrogen expands approximately 700 times in volume when vaporizing. This rapid phase change can displace oxygen in occupied spaces, creating an oxygen-deficient atmosphere. Oxygen levels below 19.5% are considered hazardous and can result in loss of consciousness or fatality.
Cryogenic Hazard
At 320°F, liquid nitrogen can cause immediate freezing of tissue upon contact. Injuries may resemble thermal burns and can result in permanent damage. Liquid nitrogen may cause material embrittlement and fracture, potentially leading to an explosion of a sealed container.
Personal Protective Equipment
Always appropriate PPE for handling cryogenic liquids:
- Cryogenic-safe gloves
- Face shield and safety goggles
- Long sleeves
- Garment and fully enclosed shoes covering all skin beneath the waist
Safe Handling Procedures
- Use and store cryogenic liquids in well-ventilated areas only.
- Cryogenic liquids will vent (boil off) under normal conditions. Containers are vacuum‑jacketed to minimize heat loss. Excessive venting or isolated ice build-up may indicate vessel failure. Remove any suspect container from service and relocate it to a safe, well‑ventilated area.
- Piping, valves and fittings must be rated for cryogenic temperatures.
- Transfer operations involving open cryogenic containers must be done slowly, while wearing all required PPE. Care must be taken not to contact non-insulated pipes and system components.
- Open transfers will be allowed only in well-ventilated areas.
- Use tongs or other similar devices to immerse and remove objects from cryogenic liquids; never immerse any part of your body into a cryogenic liquid.
Contact
Environmental Health and Safety
researchsafety@purdue.edu
765-494-6371