Cryogenic hazard class for nitrogen?

Cryogenic hazard class for nitrogen?

• A. 2.1
• B. 3
• C. 4
• D. 2.2

Answer: (D)

Cryogenic liquids are treated as non-flammable, non-toxic gases under the hazmat classification system. Nitrogen at cryogenic temperatures is extremely cold and exists as a liquid/gas mixture that can displace oxygen in confined spaces, but it does not burn and it isn’t toxic. That combination places it in Class 2 (Gases), specifically Division 2.2, which covers non-flammable, non-toxic gases and cryogenic liquids. The other options describe hazards that don’t apply to liquid nitrogen: a flammable gas class (2.1) would be for gases that ignite easily, toxic gases (3) for substances with harmful respiratory effects, and flammable solids (4) for solids that ignite. So the correct classification is 2.2.

Cryogenic liquids are treated as non-flammable, non-toxic gases under the hazmat classification system. Nitrogen at cryogenic temperatures is extremely cold and exists as a liquid/gas mixture that can displace oxygen in confined spaces, but it does not burn and it isn’t toxic. That combination places it in Class 2 (Gases), specifically Division 2.2, which covers non-flammable, non-toxic gases and cryogenic liquids. The other options describe hazards that don’t apply to liquid nitrogen: a flammable gas class (2.1) would be for gases that ignite easily, toxic gases (3) for substances with harmful respiratory effects, and flammable solids (4) for solids that ignite. So the correct classification is 2.2.