Marking, Labeling, and Placarding
Marking, labeling, and placarding communicate hazard information at three levels: the package, the vehicle, and the paperwork. Markings are printed on packages (proper shipping name, UN number, orientation arrows, RQ for reportable quantities). Labels are the diamond-shaped hazard labels applied to non-bulk packages and correspond to the hazard class. Placards are the larger diamonds placed on vehicles and bulk packages.
Candidates must know the 1,001-pound rule: placards are required when the aggregate gross weight of a class of hazardous material in non-bulk packages reaches 1,001 pounds or more. Bulk packages and certain high-hazard materials (such as Division 1.1, 1.2, 1.3, 2.3, 6.1 PG I, and 7) require placards regardless of quantity. A common trap is applying the 1,001-pound threshold to bulk packages or to materials that require placarding at any amount. Another trap: confusing label colors and symbols, or assuming a placard satisfies the package-labeling requirement.
Rule of thumb: bulk or high-hazard equals placard always; non-bulk equals count to 1,001 pounds per class.
Worked example: A truck carries 600 lb of Class 3 flammable liquid and 500 lb of Class 8 corrosive, both non-bulk. Neither class reaches 1,001 lb, so no placards are required for those classes, though each package still carries its label.