Dangerous goods freight: classified cargo under modal rules

Classification is the foundation

Every regulated substance is assigned an identification number, a hazard class and division, a packing group reflecting the degree of danger, and a proper shipping name that is used on documents in preference to a trade name. That set of attributes is what every subsequent requirement keys off. Classification is the consignor's responsibility, drawn from the safety data sheet and the applicable regulations, and a substance misclassified at this point will be wrongly packed and wrongly declared all the way down the chain.

One substance, several rulebooks

Sea carriage follows the international maritime dangerous goods code issued by the maritime regulator. Air follows the technical instructions of the international civil aviation body, applied in practice through the airline industry's dangerous goods regulations. Road, rail and inland waterway in Europe follow their own agreements administered under the United Nations economic commission, and the Commission transport directorate publishes how they apply within the Union. All descend from the same United Nations model recommendations, which is why they resemble each other, yet air is markedly stricter because an aircraft cannot pull over.

Packaging, marks, labels and placards

Regulated goods travel in packaging built and tested to a specified performance standard, identified by a certification marking on the package itself. Onto that go the hazard labels, the identification number, the proper shipping name, orientation arrows where required, and any handling marks. Where packages are combined into an overpack or loaded into a unit, the outer level carries its own marking, and vehicles and containers display placards so that responders arriving at an incident can identify what they are dealing with without opening anything.

The declaration and the documents in transit

A dangerous goods declaration accompanies the consignment, stating the classification details, the number and type of packages and the quantity in each. Air shipments use the format prescribed for that mode, and container shipments add a packing certificate confirming the unit was loaded correctly. Drivers and crews also carry instructions describing the hazards and the immediate actions to take, so information is available at the scene rather than in an office.

Segregation, stowage and quantity thresholds

Incompatible substances must be kept apart, and the rules specify how far, expressed as separation within a hold, a compartment or a vehicle. Some materials may only travel on deck; some are forbidden on passenger aircraft; some are prohibited outright. Reduced provisions exist for small quantities packed in limited or excepted arrangements, which is how many consumer goods containing regulated components move at all. Establishing which threshold applies is part of classification rather than an afterthought.

Trained people, not just correct paperwork

Everyone who classifies, packs, marks, documents or accepts these consignments must be trained and, for several modes, formally certified, with records kept and refreshed periodically. Larger operations appoint a safety adviser responsible for the regime. Carriers refuse consignments tendered by untrained shippers because the risk lands on them, and an incorrectly declared shipment discovered in transit stops the whole conveyance.

Frequently asked questions

Why are air rules stricter than sea rules for the same substance?

Because the consequences and the options differ. An aircraft cannot isolate a compartment, land immediately anywhere or fight a hold fire the way a ship's crew can, so quantities are smaller, packaging expectations higher and some materials are excluded from passenger aircraft altogether.

What does the marking on approved packaging mean?

That the package design passed the drop, stack, pressure and leakproofness tests required for the goods and packing group concerned. The code identifies the type, the materials, the performance level and the approving authority, which is what allows a carrier to accept it on sight.