Transporting dangerous goods by road, rail, air or sea carries significant risks to people, property and the environment. To manage these risks effectively, one of the most important tools used worldwide is the UN Number system. This standardised system helps ensure the safe movement of hazardous materials and supports compliance with both international guidelines and Australian regulations.
In this article, we take a closer look at what UN Numbers are, why they matter and how they are applied across international and Australian frameworks.
What is a UN Number?
A UN Number is a four digit code assigned by the United Nations to identify specific dangerous goods. These numbers provide a consistent way to classify hazardous substances based on their chemical and physical characteristics, such as flammability, toxicity or corrosiveness.
The system helps anyone involved in the handling, transport or emergency response of dangerous goods quickly understand the risks and act accordingly.
For example:
UN 1203 is the UN Number for petrol, a flammable liquid.
UN 2814 is assigned to infectious substances dangerous to humans.
How the UN Number System Works
The UN Number system organises dangerous goods into nine hazard classes, each with its own handling and safety requirements. These classes include:
- Class 1: Explosives
- Class 2: Gases
- Class 3: Flammable Liquids
- Class 4: Flammable Solids
- Class 5: Oxidising Substances and Organic Peroxides
- Class 6: Toxic and Infectious Substances
- Class 7: Radioactive Materials
- Class 8: Corrosive Substances
- Class 9: Miscellaneous Dangerous Goods
Each hazardous material is assigned a UN Number within one of these classes. This number appears on labels, documentation and placards to help ensure safe handling and emergency readiness.
International Use of the UN Number System
The UN Number system is a key component of several global regulations that govern the safe transport of dangerous goods across borders and between modes of transport.
The UN Recommendations on the Transport of Dangerous Goods
Often referred to as the Orange Book, these recommendations are issued by the United Nations Economic and Social Council. They form the basis for many international and national laws and are designed to harmonise how dangerous goods are classified, labelled and packaged.
The recommendations outline requirements for:
- Classification: Grouping goods into hazard classes and assigning UN Numbers
- Packaging: Setting packaging standards to prevent spills, leaks or contamination
- Documentation: Ensuring that UN Numbers appear clearly on all shipping papers
- Labelling and Placarding: Displaying the correct UN Number on hazard labels and transport vehicles
These guidelines influence major regulatory frameworks such as the International Maritime Dangerous Goods (IMDG) Code, the ICAO Technical Instructions and the European ADR agreement.
The IMDG Code for Sea Freight
The IMDG Code, managed by the International Maritime Organization, provides detailed rules for the shipment of dangerous goods by sea. It uses the UN Number system to identify and regulate how hazardous materials are packed, labelled and documented for marine transport.
ICAO and IATA Regulations for Air Transport
Air transport of dangerous goods is governed by the International Civil Aviation Organization (ICAO) and enforced commercially through the International Air Transport Association (IATA). Both rely on UN Numbers for identifying risks and ensuring that goods are transported safely and in line with international aviation standards.
Application in Australian Dangerous Goods Law
Australia follows the international UN Number system through its national laws and standards. These requirements are enforced under multiple frameworks, depending on the mode of transport.
The Australian Code for the Transport of Dangerous Goods by Road and Rail (ADG Code)
The ADG Code sets the rules for transporting dangerous goods within Australia by land. It adopts the UN classification system, including UN Numbers, to ensure dangerous goods are handled and transported safely.
The code outlines:
- Classification: Assigning the correct hazard class and UN Number
- Packaging: Following prescribed packaging methods for each class of goods
- Documentation and Labelling: Including UN Numbers on all declarations, shipping papers and container labels
Work Health and Safety Regulations
In addition to transport legislation, dangerous goods are also regulated under workplace health and safety laws. The Model Work Health and Safety Regulations include requirements for hazardous substances in the workplace, which align with the Globally Harmonised System (GHS).
This means employers must ensure:
- All dangerous goods are correctly labelled with their UN Numbers
- Safety data sheets (SDS) are available and up to date
- Substances are stored, handled and disposed of according to the risk they present
Compliance and Safety
Compliance with the UN Number system is critical for safety and legal protection. In Australia, enforcement is carried out by agencies such as the Civil Aviation Safety Authority (CASA), Maritime Safety Authorities, state road transport agencies and WorkSafe regulators.
Penalties for breaching dangerous goods regulations can be serious. Incorrect classification, labelling or documentation can result in fines, prosecution or significant harm to people, property and the environment.
The UN Number system plays an essential role in the safe management and movement of dangerous goods across industries. It helps classify substances based on their hazards and ensures clear, standard identification throughout the supply chain.
For Australian businesses, following the UN Number system is not just about compliance — it is about protecting workers, customers, communities and the environment.
If your business is involved in the handling or transport of dangerous goods in Australia, understanding and correctly applying UN Numbers is vital. For expert support and peace of mind, contact DG Solutions Australia. We are here to help you stay compliant and safe every step of the way.