Dangerous goods (DG) are substances and articles that can harm people, property or the environment during transport, grouped into 9 hazard classes under United Nations rules. To ship DG legally you must classify the cargo, declare it with a Material Safety Data Sheet (MSDS), and pack and label it to the rules of the transport mode, which is the IMDG Code for sea and the IATA Dangerous Goods Regulations for air.
For businesses shipping chemicals, paints, aerosols, batteries or cleaning products, DG compliance is where most rejected shipments come from. This guide covers the classes, the MSDS, how sea and air rules differ, and De Hubs’ own DG policy.
The 9 Dangerous Goods Classes
| Class | Hazard | Divisions / notes | Examples |
|---|---|---|---|
| 1 | Explosives | 1.1 mass explosion; 1.2 projection; 1.3 fire or minor blast; 1.4 no significant hazard; 1.5 very insensitive; 1.6 extremely insensitive | Fireworks, ammunition, flares |
| 2 | Gases | 2.1 flammable; 2.2 non-flammable, non-toxic; 2.3 toxic | Propane, butane, nitrogen, oxygen, chlorine, ammonia, aerosols |
| 3 | Flammable liquids | Flash point not more than 60°C | Petrol, acetone, paints, solvents |
| 4 | Flammable solids | 4.1 flammable solids; 4.2 spontaneously combustible; 4.3 dangerous when wet | Matches, sulphur, phosphorus, sodium, calcium carbide |
| 5 | Oxidisers and organic peroxides | 5.1 oxidising substances; 5.2 organic peroxides | Ammonium nitrate, MEK peroxide |
| 6 | Toxic and infectious substances | 6.1 toxic; 6.2 infectious | Cyanides, pesticides, medical specimens |
| 7 | Radioactive material | Above set activity limits | Medical isotopes, gauges |
| 8 | Corrosives | Damage skin, metals and materials | Sulphuric acid, hydrochloric acid, batteries with acid |
| 9 | Miscellaneous | Hazards not covered by Classes 1–8 | Lithium batteries, dry ice, environmentally hazardous substances |
Within many classes, substances are also assigned a packing group: I (high danger), II (medium) or III (low), which sets how strong the
packaging must be.
What Is an MSDS (Material Safety Data Sheet)?
An MSDS, now usually called a Safety Data Sheet (SDS), is the manufacturer’s technical document for a hazardous product. The standard format has 16 sections, including hazard identification, composition, handling and storage, and Section 14: transport information, which gives the UN number, proper shipping name, DG class and packing group. Forwarders read Section 14 to decide whether and how the cargo can be accepted.
In Malaysia, suppliers of hazardous chemicals must provide SDS documents under the Occupational Safety and Health (Classification, Labelling and Safety Data Sheet of Hazardous Chemicals) Regulations 2013.
MSDS checklist before shipping DG
- The product name on the MSDS matches the invoice and packing list
- Section 14 shows the UN number, class and packing group
- The MSDS is current (not an outdated version)
- Quantities per package are within the limits for the transport mode
Shipping DG Cargo by Sea vs Air
| Sea freight | Air freight | |
|---|---|---|
| Governing rules | IMDG Code | IATA Dangerous Goods Regulations |
| Strictness | Strict, with stowage and segregation rules on board | Stricter: many items are forbidden or quantity-limited |
| Approval | Shipping line approval required | Airline approval required |
| Typical issues | Segregation from incompatible cargo; container placards | Lithium batteries, aerosols, perfumes, quantity limits |
As a rule, if a product is borderline for air, sea freight is often the more practical option. See our air vs sea freight comparison.
Air rules are stricter than sea rules for many everyday products. Our guide to what you can and cannot ship by air freight lists the common restricted items, from lithium batteries to perfume.
Hidden Dangerous Goods: Items Shippers Often Forget to Declare
Many rejected shipments are not chemical consignments at all. They are ordinary cargo with a DG item inside. Check for these before you pack:
| Item | Why it is DG | Typical class |
|---|---|---|
| Lithium batteries (loose or inside devices) | Fire risk from thermal runaway | 9 |
| Aerosols (sprays, lubricants, paint cans) | Pressurised flammable gas | 2.1 |
| Perfumes and alcohol-based products | Flammable liquid | 3 |
| Paints, thinners, adhesives | Flammable liquid | 3 |
| Cleaning chemicals and bleach | Corrosive or oxidising | 8 or 5.1 |
| Machinery with fuel residue | Flammable liquid or vapour | 3 |
| Dry ice used for cooling | Asphyxiation and pressure risk | 9 |
Labels, Marks and Limited Quantities
Every DG package carries the UN number, the proper shipping name and the hazard label (the diamond-shaped class symbol). Containers carrying DG by sea also display placards on the outside. Small inner packagings of some products can travel under limited quantity or excepted quantity provisions, with simpler marking but still declared. Whether your product qualifies depends on the UN number and the mode, so confirm with your forwarder rather than assuming.
Storing DG Cargo in a Warehouse
Warehouses must keep incompatible classes apart (for example oxidisers away from flammable liquids), control ignition sources and ventilation, and hold the MSDS for every DG product on site. Not every warehouse accepts every class, so check before you send stock.
De Hubs Dangerous Goods Policy
- Not accepted: DG Class 1 (explosives) and Class 2 (gases).
- Class 3 and below: may be accepted subject to approval, a valid MSDS and carrier acceptance.
- Declaration: all DG must be declared before it is sent to our warehouse.
This applies across our sea freight, air freight and warehousing services. For document requirements, see our customs clearance checklist.
Frequently Asked Questions
What are the 9 classes of dangerous goods?
Class 1 explosives, Class 2 gases, Class 3 flammable liquids, Class 4 flammable solids, Class 5 oxidisers and organic peroxides, Class 6 toxic and infectious substances, Class 7 radioactive material, Class 8 corrosives and Class 9 miscellaneous dangerous goods such as lithium batteries and dry ice.
What is an MSDS?
An MSDS (Material Safety Data Sheet), now usually called an SDS, is a document from the manufacturer describing a product’s hazards, safe handling, storage, emergency measures and transport information, including its UN number and DG class. Forwarders use it to accept and pack DG cargo correctly.
Which dangerous goods does De Hubs accept?
De Hubs does not accept DG Class 1 (explosives) or Class 2 (gases). DG Class 3 and lower-risk cargo may be accepted subject to approval, a valid MSDS and the airline’s or shipping line’s acceptance.
Are lithium batteries dangerous goods?
Yes. Lithium batteries are Class 9 dangerous goods, and they must be declared even when packed inside equipment. Air rules are especially strict on state of charge, packing and quantity per package.
What happens if I don’t declare dangerous goods?
Undeclared DG can be rejected, held or returned, and the shipper can face fines. More importantly, it puts the vessel, aircraft, warehouse and staff at risk. Always declare DG with an MSDS before dispatch.