Handling Cryogenic Liquids

Most cryogenic liquids are odorless, colorless, and tasteless when vaporized. When cryogenic liquids are exposed to the atmosphere, the cold boil-off gases condense the moisture in the air, creating a highly visible fog.

• Cryogenic liquids MUST be used in a well ventilated area. All cryogenic liquids produce large volumes of gas when they vaporize. For example, one liter of liquid nitrogen displaces 694 liters of air when it vaporizes.
• When used in sealed containers, this vaporization can produce enormous pressures.
• Always wear proper PPE.
• Always use proper containers designed for the transport and use of cryogenic liquids.
• Examine containers and pressure relief valves for signs of defect. Never use a container which has defects.
• Always handle these liquids carefully to avoid skin burns and frostbite. Exposure that may be too brief to affect the skin of the face or hands may damage delicate tissues, such as the eyes.
• Boiling and splashing always occur when charging or filling a warm container with cryogenic liquid or when inserting objects into these liquids. Perform these tasks slowly to minimize boiling and splashing. Use tongs to withdraw objects immersed in a cryogenic liquid.
• Never touch uninsulated pipes or vessels containing cryogenic liquids. Flesh will stick to extremely cold materials. Even nonmetallic materials are dangerous to touch at low temperatures.
• Use wooden or rubber tongs to remove small items from cryogenic liquid baths. Cryogenic gloves are for indirect or splash protection only, they are not designed to protect against immersion into cryogenic liquids.
• When transferring into a secondary container, do not fill the secondary container to more than 80% of capacity.
• Check cold baths frequently to ensure they are not plugged with frozen material.