Hazardous Materials: Paperwork, Placards, and Loading
Maryland's Hazardous Materials domain tests shipping papers, placarding, loading, and emergency response. A hazmat endorsement is required to drive a CMV carrying placarded amounts, and the questions often turn on thresholds and paperwork.
Paperwork and placards
Shipping papers must include the proper shipping name, hazard class, identification number, packing group, quantity, and an emergency response telephone number. Keep them within reach while driving. Placards warn others about the hazard class. Most Table 2 materials require placards at 1,001 pounds or more aggregate gross weight; Table 1 materials and certain explosives require placards in any quantity. Placards go on both sides and both ends of the vehicle, and the ID number must match the shipping paper.
Loading and routes
Secure cylinders upright, keep incompatible materials separated, and never smoke near hazmat. Know tunnel and route restrictions. Do not fuel with the engine running. After unloading, remove placards when the vehicle no longer contains the material in a placarded quantity. The Emergency Response Guidebook gives initial isolation and protective-action advice, but the carrier's emergency number is the required contact.
Worked example
A truck carries 700 pounds of a Class 3 flammable liquid and 400 pounds of a Class 8 corrosive. The aggregate is 1,100 pounds, which exceeds 1,001 pounds, so both classes need placards. A driver who placards only the Class 3 material has missed the aggregate rule.
Traps
Placarding by individual package weight instead of aggregate; using a shipping paper without an emergency number; loading incompatible materials together; forgetting that 1,001 pounds applies to Table 2; and assuming a hazmat endorsement permits unrestricted routes.