Special Hazards and Other Regulated Materials
Beyond the nine classes, certain materials carry special rules. Radioactive materials (Class 7) require special packaging, labeling, and routing; drivers must know that exclusive use shipments have different rules. Infectious substances (Class 6.2) require careful handling and separation from food. Explosives (Class 1) have compatibility groups and require special placarding and routing. Cryogenic liquids (Class 2.2, MC-338) are extremely cold and can cause frostbite and oxygen displacement-never enter a confined space where they have vented. Oxidizers (Class 5.1) can intensify fire; keep them away from flammables. Organic peroxides (5.2) can decompose and explode if heated. Corrosives (Class 8) destroy skin and metal. Traps: questions confuse oxidizers with flammables, or claim cryogenics are harmless because they are nonflammable (they can still displace oxygen and cause frostbite). Also know hazardous waste rules and marine pollutants. Rule of thumb: read the label and the ERG; special hazards often mean special handling and separation. Worked example: A load of liquid oxygen (Class 2.2, oxidizer) must be kept away from oil, grease, and flammable cargo-oxygen supports combustion even though it is not itself flammable.