液氮
Nitrogen itself is relatively non-toxic, but in high concentrations it can displace oxygen, creating a suffocation hazard. Liquid nitrogen (−195.8 °C) presents a significant risk of frostbite or cold burn if mishandled. Proper protective clothing, such as long sleeves and gloves, should always be worn when handling these products. Liquid nitrogen is stored in compressed cylinders, and therefore presents all the hazards attendant to materials under pressure and should be handled accordingly.