Dangerous goods (DG) shipping is one of those topics that freight forwarders either handle expertly or avoid entirely. If your cargo includes lithium batteries, flammable liquids, compressed gases, aerosols, certain paints or adhesives, or any chemical with a Safety Data Sheet (SDS), you're in DG territory — and the rules are strict.
Every year, ships catch fire and planes divert because someone decided their lithium battery shipment was "basically fine" and skipped the paperwork. The consequences range from cargo rejection and detention to international incidents and criminal charges. So let's go through how DG shipping actually works.
What Makes Something a Dangerous Good?
Dangerous goods are materials that pose a risk to health, safety, property, or the environment during transport. The classification isn't based on what you call the product — it's based on the physical and chemical properties of the substance.
The two main international frameworks:
- IMDG Code (International Maritime Dangerous Goods Code) — governs sea freight
- IATA DGR (IATA Dangerous Goods Regulations) — governs air freight
Both are based on the UN Model Regulations and use the same nine hazard classes, but the specific packing, labeling, and declaration requirements differ between modes.
The Nine Hazard Classes
| Class | Category | Common Examples |
|-------|----------|-----------------|
| Class 1 | Explosives | Fireworks, flares, airbag inflators |
| Class 2 | Gases | Propane, aerosols, oxygen cylinders |
| Class 3 | Flammable Liquids | Paints, adhesives, perfumes, acetone |
| Class 4 | Flammable Solids | Matches, magnesium powder |
| Class 5 | Oxidizers & Organic Peroxides | Hydrogen peroxide, bleach |
| Class 6 | Toxic & Infectious Substances | Pesticides, certain medical samples |
| Class 7 | Radioactive Material | Medical isotopes, X-ray equipment |
| Class 8 | Corrosives | Battery acid, drain cleaners |
| Class 9 | Miscellaneous | Lithium batteries, dry ice, magnetized material |
Lithium batteries are Class 9 — often considered "the easy one." They're not. Lithium battery fires are among the most difficult to extinguish, and airlines and shipping lines have strict rules about state of charge, packaging, and quantity per package. A poorly packaged battery pallet has caused multiple cargo aircraft losses.
What Is an MSDS / SDS and Why Does It Drive Everything?
A Material Safety Data Sheet (MSDS) — now standardized internationally as a Safety Data Sheet (SDS) under GHS (Globally Harmonized System) — is the foundational document for any hazardous product. It describes the substance's properties, hazards, safe handling procedures, and emergency response information.
The SDS has 16 standardized sections. For DG shipping purposes, the critical sections are:
- Section 2 — Hazard identification (GHS classification, signal words)
- Section 9 — Physical and chemical properties (flash point, vapor pressure, boiling point — these determine DG classification)
- Section 14 — Transport information: UN number, proper shipping name, hazard class, packing group, environmental hazards
If a product's SDS Section 14 shows a UN number, it's regulated as dangerous goods in transport. Full stop. No exceptions because it's in a small quantity or because your competitor ships it without paperwork.
Your Chinese supplier should provide SDS documents for any chemical, battery, or hazardous product. If they can't produce one, that's a serious supply chain risk — both regulatory and physical.
Key Documents for a DG Shipment from China
1. Dangerous Goods Declaration (DGD)
For sea freight under IMDG, this is a shipper-signed declaration certifying that the goods are classified, packaged, marked, and labeled in compliance with the IMDG Code. For air freight, it's the IATA Shipper's Declaration for Dangerous Goods — a specific multi-part form with very precise formatting requirements.
Only a trained and certified person can sign a DG declaration. In China, this is typically the exporter's DG-certified staff. The certification is not optional — a declaration signed by an uncertified person is invalid and can result in criminal liability.
2. Packing Certificate
For IMDG, a Container/Vehicle Packing Certificate confirms that the container was packed in accordance with IMDG requirements — correct placement, stowage away from incompatible goods, etc.
3. Compliance with UN-approved Packaging
DG shipments require UN-certified packaging — boxes, drums, or jerricans tested to UN performance standards. You'll see markings like "UN 4G/Y30/S" on compliant cartons. Standard commercial packaging is not acceptable for most DG classes.
4. Labels and Marks
Each package must display:
- The hazard class diamond label in correct size and color
- UN number
- Proper shipping name
- Net quantity
- Shipper and consignee details
For IMDG: a marine pollutant mark if applicable, and a placard on the container exterior.
Why Most Forwarders Are Cautious About DG
Standard freight forwarders handle DG occasionally but aren't always specialists. For a forwarder, accepting a DG shipment with incomplete documentation creates serious liability — cargo claims, shipping line fines (which can run $10,000+ per incident), potential port detention, and in extreme cases, association with incidents at sea or in the air.
Many forwarders simply decline DG cargo that isn't clean — correctly classified, properly documented, and packaged in UN-spec packaging — because the downside risk isn't worth the margin on one shipment.
The practical result: if your goods are DG, you need to either work with a forwarder that has dedicated DG expertise, or invest in getting your product documentation in order before you approach the market.
What This Means for Your China Sourcing
Before your first order of anything chemical, battery-powered, aerosol, or otherwise potentially hazardous:
- Request and review the SDS from your supplier
- Identify the UN number and hazard class from SDS Section 14
- Confirm the shipping mode (sea vs. air — lithium battery rules differ significantly)
- Check quantity thresholds — some DG classes have "limited quantity" or "excepted quantity" provisions that simplify requirements for small amounts
- Verify your forwarder has DG-certified staff and accepts your specific class
The ChinaLogisticHub customs clearance guide covers what happens after your DG shipment arrives at destination — including inspection protocols that apply specifically to regulated cargo.
If you have an upcoming DG shipment from China, reach out via the freight inquiry page with your SDS and we can advise on routing, documentation requirements, and which carriers will accept your cargo class.