How to Ship Hazmat: A Step-by-Step Guide

Shipping hazmat — hazardous materials, also called dangerous goods — is a regulated process, not a packing decision. The same article can be perfectly legal in one box and a reportable violation in another, and the difference is whether you followed the sequence below. This guide walks through how to ship hazardous materials end to end: classify, choose the regulation, pack, mark and label, complete the paperwork, and hand off to someone trained to offer the shipment.

One thing up front: this is educational. Actually offering a dangerous goods shipment for transport requires trained, often certified personnel, and the authoritative answer for any given shipment is the current regulation text — not a blog post. DG Inspector is a young product; where we mention it below, it is as a tool that verifies classification and compliance, not as a substitute for the regulation or for a trained shipper.

Step 1 — Classify the material

Everything downstream depends on getting the classification right. For each item you need four things:

• UN number — the four-digit identifier (e.g. UN3480 for lithium-ion batteries shipped on their own).
• Proper shipping name — the exact name from the dangerous goods list, not a trade or marketing name.
• Hazard class (and any subsidiary risk) — which of the nine classes the material falls into.
• Packing group — I, II or III, the degree of danger that drives the packing instruction.

If you are not sure where to start, our complete guide to UN numbers and hazard classes breaks down the structure, and the UN number lookup walkthrough shows how to go from a material to its entry. This is the step where DG Inspector helps most directly: photograph the package and it proposes the UN number, hazard class and packing group, which you then confirm against the regulation.

Step 2 — Choose the transport mode and regulation

The mode of transport decides the rulebook. The classification is broadly harmonised, but packing, marking, labelling and documentation differ between modes:

• Air → IATA DGR (the airline implementation of the ICAO Technical Instructions). The strictest mode, with the smallest quantity limits.
• Sea → IMDG Code. Used for ocean freight and containerised shipments.
• US road / rail → 49 CFR, the US hazardous materials regulations enforced by PHMSA.
• European road → ADR.

If your shipment touches more than one mode (a common case for forwarders), you generally have to satisfy each mode's rules for its leg. Our breakdown of IATA vs IMDG vs 49 CFR vs ADR explains which one applies and where they diverge.

Step 3 — Pack to specification

Once you have the UN number and packing group, the regulation points you to a packing instruction. It tells you the permitted inner and outer packagings, quantity limits per package, and whether UN-specification (performance-tested) packaging is required. Do not improvise: a packaging that "looks sturdy" is not the same as one that has passed the drop, stack and pressure tests the packing instruction calls for. Lithium batteries in particular have detailed state-of-charge and packaging rules — see the lithium battery shipping guide if that is what you are moving.

Step 4 — Mark and label the package

Marks and labels are how the package communicates its hazard to everyone who handles it. Depending on mode and classification you will typically need:

• The UN number and proper shipping name marking.
• The hazard class diamond label(s), including any subsidiary risk.
• Handling labels and orientation (this-way-up) arrows where required.
• The shipper and consignee details, and any mode-specific marks (e.g. the lithium battery mark, environmentally hazardous substance mark).

Wrong, missing or illegible labels are one of the most common reasons a shipment is rejected or fined — see the hazmat shipping mistakes that draw $25,000+ fines.

Step 5 — Complete the dangerous goods declaration

The declaration (in air, the Shipper's Declaration for Dangerous Goods; on road, the dangerous goods entry on the transport document/shipping paper) is the legal record that the shipment was prepared correctly. The regulation specifies the exact fields and the order in which the classification elements must appear. An otherwise perfect shipment can be rejected for a declaration that transposes two fields. This is the other place DG Inspector helps: it generates the inspection result and the shipping paper / DG declaration / transport document from the verified classification, so the fields and sequence come straight from the rule rather than from memory.

Step 6 — Hand off to a trained, certified shipper

Finally, the shipment has to be offered by trained personnel — in most modes, formally certified personnel — and the carrier or freight forwarder performs an acceptance check before it moves. That acceptance check is your last line of defence: it is far cheaper to catch a misclassification at the counter than in transit or in an audit. If you operate that acceptance counter, see how DG Inspector fits a freight forwarder's acceptance workflow.

What DG Inspector does — and doesn't — do

To be precise about scope: DG Inspector classifies a package from a photo or scan (UN number, hazard class, packing group), checks that classification against IATA DGR, IMDG, 49 CFR and ADR, flags problems, and generates the inspection result, shipping paper, DG declaration and transport document. It is fast — results in seconds — and it is built as a co-pilot for the steps above. It does not book carriers, sell packaging, or replace the trained shipper who offers the consignment. Treat it as the tool that verifies your classification and compliance, with the regulation and a qualified DG specialist as the final authority.