A surprising fraction of routine marine supplies are technically classified as hazardous - paints with flammable solvents, certain cleaning chemicals, lithium batteries, refrigerant gases, oxygen cylinders, calcium carbide for acetylene generators on some vessels. These items move through a dedicated logistical and regulatory framework that is meaningfully different from general cargo handling. For chandlers supplying vessels at Chennai Port, getting the handling right is part of the operational competence the rest of the supply depends on.
The IMDG Code as the framework
The International Maritime Dangerous Goods Code classifies hazardous materials into nine classes - explosives, gases, flammable liquids, flammable solids, oxidising substances, toxic substances, radioactive materials, corrosives, and miscellaneous dangerous goods. Each class has subdivisions, packing instructions, labelling requirements, segregation rules, and documentation requirements.
An item's IMDG classification determines how it can be transported, how it must be packaged, how it should be labelled, and how it can be stowed on the vessel. The classification is found in the safety data sheet (SDS) for each chemical and in the regulatory listings for each defined hazardous good.
Documentation: the dangerous goods declaration
Every shipment of hazardous goods to a vessel requires a Dangerous Goods Declaration (DGD) signed by the shipper. The declaration specifies the proper shipping name, IMDG class, UN number, packing group, quantity, packing details, and emergency response information. The DGD travels with the goods and is presented to the vessel at handover.
Shortcuts on the DGD - missing information, wrong classification, incomplete emergency response data - are not just paperwork issues. They expose the chandler, the carrier, and the receiving vessel to significant regulatory liability if anything goes wrong. The declaration discipline is fundamental.
Packaging and labelling
Hazardous materials must be packaged in UN-approved packaging suitable for the specific class. The packaging carries the UN approval mark indicating the test category passed. Labelling shows the IMDG class diamond, the UN number, the proper shipping name, and any required handling labels (orientation arrows, fragile markings).
For chandlers, this means hazardous materials cannot be casually repackaged into general transport containers. The original packaging must be maintained or replaced with equivalent UN-approved packaging.
Segregation rules
Different hazardous classes cannot be transported or stored together because of incompatibility risks. Acids and oxidisers must be segregated from each other, and both must be segregated from flammables. The segregation matrix in the IMDG Code specifies which combinations require physical separation, which can be in the same compartment but separated, and which can be stowed together.
For chandler warehouse operations, this means dedicated segregated storage areas for different hazard classes - not a single hazardous-materials room with everything mixed together.
Transport to the vessel
Vehicles carrying hazardous materials require specific licensing, driver qualifications, and emergency equipment. The route from warehouse to port may have specific restrictions on hazardous transport. Port gate procedures for hazardous materials are typically more demanding than for general supplies - additional escorts, specific entry routes, dedicated staging areas.
None of this is impossible to handle, but it requires planning rather than treating the hazardous shipment as one more line item on a routine supply run.
On-board handling at handover
The vessel's chief officer or designated cargo officer is responsible for accepting hazardous materials onto the vessel and stowing them in the appropriate hazardous-materials locker. The handover should include verification of the DGD, inspection of packaging integrity, confirmation of labelling, and signed acknowledgement. Items with damaged packaging or missing documentation should be refused, not accepted with a note for later resolution.
Emerging categories: lithium batteries
Lithium batteries deserve specific mention. Damaged or substandard lithium cells can fire violently and have caused incidents in maritime, aviation, and ground transport. The regulatory framework around lithium battery transport has tightened significantly. Specific UN numbers, packing instructions, and quantity limits apply. For vessels equipped with battery-powered tools, emergency power packs, or lithium-based UPS systems, lithium battery supply has become a meaningful logistics category in its own right.
The competence question
Hazardous materials handling is not a casual capability. Personnel involved should be trained against the IMDG Code, periodic refresher training should be documented, and the operational procedures should be auditable. Chandlers handling hazardous materials as a routine part of supply should be able to demonstrate this training depth on request.
Done well, hazardous materials supply is invisible. Done badly, it becomes the incident report nobody wanted.
For IMDG-compliant hazardous materials supply at Chennai Port, see our ship chandler at Chennai Port compliance scope.