What is the primary hazard class associated with Cryogenic Liquid Tank Cars?

Cryogenic Liquid Tank Cars primarily fall under Hazard Class 2, which encompasses gases. This classification is specifically applicable to materials that are in a gaseous state at normal temperature and pressure, but can be stored as liquids at very low temperatures.

Cryogenic liquids, such as liquefied natural gas (LNG) or liquid oxygen, present unique hazards mainly due to their extremely low temperatures. The risks include severe frostbite or cold burns upon contact with skin, and the potential for rapid release of gas, which can create explosive atmospheres or suffocation hazards in confined spaces.

This distinction as a hazardous material is critical for emergency responders and technicians. Understanding the nature of these materials ensures that appropriate safety measures are taken during transport, storage, and emergency response operations. The other hazard classes mentioned do not apply to cryogenic liquids: class 1 deals with explosives, class 5 involves oxidizers, and class 6 relates to toxic substances—none of which accurately categorizes the primary hazards associated with cryogenic tank cars.