Marking, Labelling, Placarding and Documentation
Labels and marks
Each package must carry the UN number and the proper shipping name, plus hazard labels for the primary and subsidiary risks. Labels are diamond-shaped; the class number appears at the bottom. Special marks include the environmentally hazardous substance mark and, for some goods, orientation arrows. Traps: confusing labels (on packages) with placards (on vehicles), and forgetting that subsidiary labels are mandatory when a subsidiary risk is listed.
Placards and the vehicle
Vehicles carrying dangerous goods above the exemption thresholds must display orange plates at front and rear, and hazard placards on both sides. The orange plate shows the hazard identification number (top) and the UN number (bottom). A common trap is reversing the two numbers, or forgetting the placards when the load exceeds the threshold.
Documentation
The transport document must state the UN number, proper shipping name, class, packing group, number and description of packages, total quantity, consignor and consignee, and any special provisions. The driver must also carry the instructions in writing (the four-page emergency card) in the language of the crew. Traps: missing packing group, missing subsidiary risk, and a transport document that does not match the placards.
Worked rule of thumb
Read the orange plate top-to-bottom: hazard identification number first, then UN number. Cross-check both against the transport document. If the document and the plate disagree, the load is not ready to move.