Which cargo is typically carried by MC331 high-pressure tanks?

• A. Propane, butane, chlorine, anhydrous ammonia
• B. Liquid oxygen, hydrogen, carbon dioxide
• C. Ammonium nitrate fertilizer, cement, plastic pellets, caustic soda powder
• D. Petroleum

Answer: (A)

MC331 high-pressure tanks are built for compressed gases that stay in the gas phase at normal temperatures and are stored under high pressure. This design suits gases like propane and other liquefied petroleum gases, plus chlorine and anhydrous ammonia, which are routinely hauled under high pressure to keep them contained and manageable on the road. The other cargos listed don’t fit this tank type: cryogenic liquids such as liquid oxygen, hydrogen, and carbon dioxide require very low temperatures and different insulation/containment; powders and solids like fertilizer or cement use bulk dry or bulk liquid systems, not high‑pressure gas tanks; and petroleum products are typically carried in non‑pressure liquid cargo tanks designed for liquids rather than compressed gases.