Which DOT Class includes radioactive materials?

• A. DOT Class 5
• B. DOT Class 3
• C. DOT Class 7
• D. DOT Class 8

Answer: (C)

Radioactive materials are assigned to DOT Class 7 because the defining hazard is ionizing radiation, not chemical reactivity or flammability. This classification signals the need for radiological controls, specialized labeling (the radiation trefoil), and specific handling, packaging, and regulatory requirements for transport. Knowing it’s Class 7 tells responders to expect radiation-related risks and to follow appropriate shielding, distance, and time precautions as well as radiological procedures. For context, other classes cover different hazards—for example, flammable liquids are Class 3, oxidizers and organic peroxides are Class 5, and corrosives are Class 8—so identifying a shipment as Class 7 specifically flags radioactive material and the corresponding safety measures.