Special Hazard Classes: Explosives, Radioactive, Poison Inhalation, and Hazardous Wastes
This domain covers the classes that carry rules beyond ordinary labeling: explosives, radioactive material, poison inhalation hazards, and hazardous waste. These questions reward precision over general knowledge.
Explosives (Class 1)
Divisions 1.1 through 1.6, each with a compatibility group lettered A through S. Placards show both, such as EXPLOSIVES 1.1D. Rules include no smoking, careful securement, segregation of detonators from other explosives except where the table permits, attendance requirements, and route and parking restrictions. Exclusive use means the vehicle carries only that shipment.
Radioactive (Class 7)
Labels are RADIOACTIVE WHITE-I (transport index zero), YELLOW-II (transport index up to 1.0), and YELLOW-III (transport index above 1.0, up to 10 for non-exclusive use). The transport index comes from the highest radiation level measured one meter from the package surface. Packages must be secured, kept away from occupied areas, and many shipments require exclusive use.
Poison inhalation hazards
Division 2.3 gases and Division 6.1 PG I materials with inhalation toxicity are PIH. Hazard Zones A through D run from most to least toxic. Packages carry POISON-INHALATION HAZARD or INHALATION HAZARD markings, they are barred from vehicles carrying food, and the ERG green pages govern isolation.
Hazardous waste
Waste moves on an EPA Uniform Hazardous Waste Manifest with a shipping description that puts Waste before the proper shipping name, for example "Waste Flammable liquid, n.o.s., 3, UN1993, PG II." The shipment must go to a permitted facility, the driver signs and keeps a copy, and a load offered without a manifest is refused.
Worked example
A generator offers a tote of spent solvent with a manifest reading "Flammable liquid, n.o.s., 3, UN1993, PG II." It is missing the word Waste - a paperwork defect the exam will expect you to catch.
Traps
Treating PIH like an ordinary 6.1 poison; assuming Yellow-III packages may ride in any vehicle; forgetting the Waste prefix; signing a manifest you have not checked.