IMDG Class 9 is the catch-all hazard class for substances and articles that present a transport hazard but do not meet the criteria for Classes 1 through 8. It covers a heterogeneous group: lithium batteries (the fastest-growing entry by volume), environmentally hazardous substances, asbestos, dry ice, magnetised materials, and elevated-temperature substances. The class has expanded materially since 2015 as lithium-battery shipping has overtaken many traditional Class 9 entries by volume.
What sits inside Class 9
| Sub-grouping | Examples | Notes |
|---|---|---|
| Lithium batteries | UN 3480 (Li-ion alone), UN 3481 (Li-ion in/with equipment), UN 3090 (Li-metal alone), UN 3091 (Li-metal in/with equipment) | Subject to specific testing (UN 38.3) and packaging rules |
| Environmentally hazardous substances | UN 3077 solid, UN 3082 liquid | Substances marine-pollutant or aquatic-toxic but not toxic enough to fit Class 6.1 |
| Elevated-temperature substances | UN 3257 (liquid above 100°C), UN 3258 (solid above 240°C) | Molten sulphur, molten asphalt, molten metal |
| Magnetised materials | UN 2807 | Sufficient magnetic field strength to interfere with aircraft navigation |
| Asbestos | UN 2212 (chrysotile), UN 2590 (other) | Heavily restricted, banned in many destinations |
| Dry ice | UN 1845 | Sublimation generates CO2; ventilation required |
| Polymeric beads, expandable | UN 2211 | Expanded polystyrene precursors |
| Genetically modified microorganisms | UN 3245 | When not toxic or infectious enough for Class 6.2 |
Most Class 9 entries do not have a packing group assignment, the hazard is too varied to slot into the PG framework. A few do (UN 3077 and UN 3082 environmentally hazardous substances are typically PG III).
Lithium batteries, the dominant Class 9 cargo
Since approximately 2018 lithium batteries have been the largest single Class 9 cargo by volume. Four UN numbers cover the routine shipping cases:
- UN 3480. Lithium-ion batteries shipped alone (not in equipment)
- UN 3481. Lithium-ion batteries packed with equipment OR contained in equipment
- UN 3090. Lithium-metal batteries shipped alone
- UN 3091. Lithium-metal batteries packed with equipment OR contained in equipment
Every battery requires UN 38.3 test certification before shipment. The certificate must be available on request. Without it, the carrier will refuse the cargo. The factory typically provides the UN 38.3 test report for the specific cell or battery design at the time of order.
State of charge matters. Lithium-ion batteries shipped under UN 3480 (alone) by sea must be at 30% state of charge or less. Many Chinese factories ship at full SoC by default unless the buyer specifies. The carrier’s pre-load inspection at major ports increasingly checks SoC and will reject over-charged cargo.
Environmentally hazardous substances (UN 3077, UN 3082)
These two UN numbers are the catch-all for substances that are marine-pollutant or aquatic-toxic but do not meet the criteria for Classes 1 through 8. UN 3077 covers solids (e.g. some powdered pesticide formulations, some solid copper compounds, some lead salts). UN 3082 covers liquids (many pesticide formulations, certain oil products, environmentally toxic solvents).
The “fish and tree” marine pollutant marking is mandatory on these cargoes. The marking requirement is independent of the Class 9 placard, both must appear on the package. A buyer importing aquatic-toxic specialty chemicals from China will routinely see the cargo classified as UN 3082 with the marine pollutant flag and the Class 9 placard.
Elevated-temperature substances
UN 3257 (liquid above 100°C, but below the substance’s flash point if flammable) is the routine designation for molten sulphur shipping out of Chinese refineries to fertiliser markets. The cargo is in stainless or low-alloy steel ISO tanks heated to maintain liquid state during the voyage. Heated tank shipping carries a substantial freight premium versus solid sulphur in bulk carriers, typically USD 80 to USD 150 per tonne extra, but for buyers with downstream sulphuric acid plants accepting molten feed, the avoided remelting cost compensates.
Carrier surcharges on Class 9
Class 9 cargo often attracts a hazmat surcharge from the carrier. The surcharge varies by class, route, and carrier, typically USD 100 to USD 800 per container above a baseline freight rate. Lithium-battery cargo specifically attracts higher surcharges and sometimes carrier-specific quotas. Maersk and MSC both periodically restrict lithium-battery booking volumes during peak season.
For a buyer building landed-cost models on Class 9 cargo, the hazmat surcharge is a moving line item. Quote freshness matters, a 4-week-old freight quote on a lithium-battery FCL is likely to be obsolete if there has been a carrier surcharge revision.
Operator note: the lithium-battery export licence
Some Chinese provinces require a specific export-permit for lithium-battery shipments above a quantity threshold. The threshold and the licensing province changes. Shenzhen and Shanghai have at various times added lithium-battery export controls beyond the national MEE rules. Confirm with the freight forwarder at the time of booking that the cargo qualifies for current export-permit conditions. The failure mode is the cargo being held at the export terminal pending permit issue.
Related terms
IMDG umbrella code. UN number. Marine pollutant often co-applied with Class 9. MARPOL Annex II for marine-environment classification overlap.