Flammable liquids and oil-based substances are inherently dangerous, so it’s hardly surprising they’re among the most heavily regulated areas of international freight. There are many risks to getting it wrong; the immediate safety risks are obviously a top concern, but infractions can also lead to other consequences, like legal liability or extensive, costly delays at customs. Crucially, those consequences apply whether or not the business itself is aware of the rules.
This is where our experts can help here at Tuplin. We have more than 40 years of experience in helping customers to ship all kinds of goods across the globe, up to and including flammable and hazardous substances. With that in mind, we’ve outlined the key regulations, classification requirements and packing obligations you need to be aware of.
Are flammable liquids and oils classified as dangerous goods?
Yes. International transport regulations classify flammable liquids as Class 3 dangerous goods because they can release vapours that ignite during storage, handling or transit. This category covers a wide range of substances frequently exported by various businesses, including:
- mineral oils
- lubricants
- hydraulic fluids
- fuel oils
- solvents
- paints
- adhesives
- cleaning fluids
The classification applies regardless of the volume being shipped – small consignments can still create a significant hazard if the product leaks, or comes into contact with an ignition source, or reacts with another substance. The goods therefore need to be classified, handled and documented correctly before they enter the freight network. The quantity being shipped is still relevant though, as it may change which exemptions or reduced requirements apply – so exporters still need to identify every hazard associated with the product before arranging transport.
Some oil-based substances may also be categorised into subsidiary hazard classes if they present additional risks, such as toxicity or corrosivity. These extra classifications can affect the packaging, labelling, segregation and handling requirements for the shipment, which is one of the main reasons why it’s so crucial that exporters check the full transport classification for each product.
Which regulations apply? ADR, IATA and IMDG
Every dangerous goods shipment must be assessed against the rules for each transport mode that will be used during its journey. A multimodal shipment may need to comply with several sets of rules as it moves by road, air or sea, so exporters will need to account for these at every stage of the journey.
ADR
ADR is the European Agreement Concerning the International Carriage of Dangerous Goods by Road. True to its name, it governs dangerous goods shipments travelling by road across the UK and Europe. Its requirements cover classification, packaging, labelling and transport documentation, alongside the operation of the vehicles carrying the goods. The current ADR 2025 edition essentially provides the basis for many domestic road transport rules.
IATA
The International Air Transport Association Dangerous Goods Regulations apply to all dangerous goods shipments travelling by air, and detail the technical requirements issued by the International Civil Aviation Organization. Air freight places particularly strict controls on flammable liquids, with tight quantity limits and complete prohibitions for some substances. The regulations specify how the goods must be classified, packed, marked, and declared before an airline can accept the shipment. It’s worth noting that some airlines may also impose additional restrictions, so it’s always wise to check the carrier’s requirements during the booking process.
IMDG
The International Maritime Dangerous Goods Code applies to dangerous goods carried by sea in packaged form. Sea freight often allows larger quantities of flammable liquids, though they’re still subject to strict packaging, stowage and segregation requirements. The Code also contains detailed rules for container loading, with specific provisions for separating substances that could react dangerously during transit. Amendment 42-24 became mandatory on 1 January 2026, so sea freight shipments must now follow the updated 2024 edition of the Code.
All three frameworks draw on the UN Model Regulations, which provide a common basis for the international transport of dangerous goods. Each framework then applies its own detailed rules for packaging, labelling, documentation and quantity limits according to the transport mode involved. Exporters therefore need to review the complete journey before preparing the consignment. For example, a shipment that travels by road to a port before continuing by sea must comply with ADR during the road leg, and IMDG during the sea leg of the trip.
How flammable liquids are classified – UN numbers and packing groups
As part of the classification process, each dangerous item is assigned a four-digit UN number that identifies the substance or the relevant category of goods, and links it to the requirements that apply.
Common UN numbers associated with oils and flammable liquids include:
- UN 1268 – petroleum distillates, not otherwise specified
- UN 1993 – flammable liquid, not otherwise specified
- UN 3082 – environmentally hazardous substance, liquid, not otherwise specified
UN 3082 applies to certain oils that present an environmental hazard and may fall within Class 9, so exporters must use the classification that reflects the product’s actual properties. The Safety Data Sheet will often provide the relevant transport information, though the consignor retains responsibility for assigning the correct classification.
The hazardous cargo packing group indicates the degree of danger presented by the substance. Packing Group I covers substances that present a great danger, Packing Group II covers a medium danger, and Packing Group III covers a low danger. Flammable liquids often fall within Packing Groups II or III, depending on properties like their flash point and initial boiling point.
The packing group also helps to determine which packaging specification is most suitable for the shipment. If certified packaging is required, the packaging needs to have UN approval; it must have passed the relevant performance tests and must be used in accordance with its approval documents. It’s worth noting that a UN mark alone doesn’t confirm that the packaging is suitable for every substance, so the exporter will need to check the certificate and test information for the particular contents.
These classification details carry through into every stage of the shipment, which means that any error can affect the way that the goods are prepared and accepted for transport. An incorrect UN number or packing group can lead to unsuitable packaging, inaccurate documentation, and invalid hazard markings. That means, for example, that the carrier may refuse the shipment, or it may be held by customs or enforcement authorities. Incidents like that could expose the exporter to legal costs, or even an uninsured liability.
What are the packaging requirements for flammable liquids?
Once the exporter has established the correct UN number and packing group, they must then ensure that the packaging meets the requirements that apply to the substance and its transport route. Each component needs to contain the liquid securely and protect the shipment throughout handling and transit.
Use UN-approved packaging
As discussed above, all packaging used for fully regulated shipments must be UN-approved and tested for the relevant packing group. The UN certification code marked on the packaging will identify the packaging type, its construction material, its performance level, and the conditions that apply to its use. The code must correspond with the permitted maximum mass or specific gravity for the contents.
Check material compatibility
The inner and outer packaging must be compatible with the substance being shipped. Some flammable liquids can react with particular sealants or linings, which can weaken the packaging and increase the risk of a leak. So, a key prerequisite for the packaging is that it must be durable enough to last for the entire journey.
Some of the most common formats include closed-head drums, jerrycans and composite packaging. The most appropriate option will depend on a variety of different factors, such as the shipment volume or transport mode.
Include absorbent materials
Liquid shipments must include enough absorbent material to contain the contents if a leak occurs. The material must be chemically compatible with the substance and positioned so that it can absorb any liquid that may be released from the inner packaging.
Prevent movement and impact damage
Any outer cases or crates must prevent the containers from moving during transit and protect them against impacts. Internal restraints, cushioning and bracing must keep the contents secure throughout loading, handling and onward transport. (At Tuplin, we manufacture bespoke timber cases to meet these requirements, as well as accounting for the dimensions, weight and transport conditions of each shipment.)
Apply the correct labels and markings
Every package must clearly display the required dangerous goods information. This includes the Class 3 hazard diamond, the UN number, the proper shipping name, the packing group indicator and any subsidiary hazard labels that apply to the substance. Depending on the circumstances, some additional marks may also be required, such as orientation arrows and specific environmentally hazardous substance marks.
What are the documentation requirements?
Dangerous Goods Note
For road and sea freight, exporters can use a Dangerous Goods Note to provide the required transport details. This should include:
- the proper shipping name
- UN number
- hazard class
- packing group
- total quantity
- number of packages
- required emergency contact details
These details must correspond with the information shown on the packaging and labels. The exporter must also check that the description follows the required sequence and terminology, as carriers use the document to identify the goods and the controls that apply during transport.
A Dangerous Goods Note can be used across several transport modes, but excluding air freight, which normally requires an IATA Shipper’s Declaration.
Air freight documentation
Air freight requires an IATA Shipper’s Declaration for Dangerous Goods, accompanied by an Air Waybill. Both documents must accurately reflect the shipment’s classification, quantity and packaging details. The declaration confirms that all transport arrangements conform to the IATA Dangerous Goods Regulations, while the Air Waybill links that declaration to the consignment. Any discrepancy between the documents can lead the airline to reject the shipment before loading.
Sea freight documentation
Sea freight requires an IMDG-compliant dangerous goods transport document. The relevant declaration can appear within the Bill of Lading, or be provided as a separate document. In either case, it gives the shipping line and port operators the information that they need to plan the handling, stowage and segregation of the goods.
Safety Data Sheet
The Safety Data Sheet should remain available throughout the transport chain. It gives each carrier the information that they need about the substance’s hazards, handling requirements and emergency measures. Section 14 normally contains the transport classification, including the UN number, proper shipping name, hazard class and packing group. The information on the Safety Data Sheet must correspond with the dangerous goods declaration and the package markings, as any inconsistency can prompt the carrier to request clarification or revised paperwork.
Export licences and destination requirements
Certain chemical substances may also require an export licence or additional destination-specific paperwork. At Tuplin, we can advise exporters on the requirements that apply to their destination and can prepare the dangerous goods documentation as part of our hazardous cargo packing service.
How do we manage dangerous goods shipments at Tuplin?
Exporting flammable liquids and oil-based substances is a notably more involved process than other types of cargo, but it’s relatively straightforward as long as the shipment has been classified accurately, packed correctly, and accompanied by complete documentation before it leaves the site. The regulatory framework is highly specific, and its requirements can vary according to the transport mode, destination, country and carrier. That’s where our experience at Tuplin can help.
Our trained team manages hazardous goods shipments under ADR, IATA and IMDG across road, air and sea freight. We can assess each substance, confirm its classification, choose the appropriate UN-approved packaging, and handle the case design and manufacture. We can also prepare the required dangerous goods documentation for the journey. What’s more, we carry certified 4G cartons and work with suitable container types for liquid dangerous goods. Our team can advise on airline requirements and carrier-specific restrictions, which is especially important because the rules for flammable liquids can vary significantly between countries and airlines.
Our export packing can be completed at your facility or at any Tuplin location, so you can count on us to help you prepare your goods for international transport – we can also arrange for freight forwarding if necessary. Contact our team today to discuss your shipment.
