The Rules Just Changed: IMO's HNS Convention Enters into Force in 2027

A New International Maritime Law Enters Into Force in 2027

The International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances by Sea — the HNS Convention — will enter into force in 2027. If your vessel carries chemicals, liquefied gases, bulk solids with hazardous properties, or packaged dangerous goods, this convention creates new liabilities, new compensation mechanisms, and new obligations that will touch your operations from the moment it enters into force.

What Is Classified as HNS?

Hazardous and Noxious Substances covers a wide range of cargo: oil (not already covered by CLC), chemicals carried in bulk, liquefied gases, liquid substances carried in bulk with a flashpoint not exceeding 60°C, solid bulk materials with hazardous properties, and certain packaged goods. The convention establishes a two-tier compensation system — shipowner liability in the first tier, and a separate HNS Fund (financed by receivers of HNS cargo) in the second tier. It provides for compensation for death, injury, property damage, economic loss, and environmental remediation in the event of an HNS incident.

Why It Matters Operationally

Mandatory Insurance

Ships carrying HNS will be required to maintain insurance or other financial security covering the owner’s HNS liability. Certificates of insurance will be required on board and subject to port state verification. Vessels without valid HNS insurance certificates will face port entry restrictions.

Emergency Response Planning

The heightened liability framework under HNS creates a stronger commercial and legal imperative for effective emergency response planning for cargo incidents. A chemical spill or explosion involving HNS cargo on a vessel with inadequate emergency plans and untrained crew will now fall within a formal compensation framework — and the shipowner’s liability exposure is directly connected to the quality of the vessel’s safety and response arrangements.

Cargo Information Accuracy

The convention relies on accurate declaration of HNS cargo to function. Misdeclared or undeclared HNS cargo is not just an IMDG Code violation: under the new convention, it becomes a liability issue that could affect compensation claims. Masters and cargo officers need to be more attentive than ever to the accuracy and completeness of dangerous goods declarations.

Crew Awareness at Sea

When an HNS incident occurs, the response in the first minutes determines both human survival and the scale of environmental damage. Crew who understand the properties of the hazardous substances they are carrying, know where the safety data sheets are, and have rehearsed emergency response for a cargo release are incomparably better placed than those who do not.

The 18 months between now and entry into force is not a long runway for compliance preparation, crew training updates, and insurance arrangement reviews. Identify the hazardous cargoes on your current voyage or vessel schedule. Pull the Safety Data Sheets. Read the emergency response section. Then ask your cargo officer: if this cargo released right now, what do we do?

Related Reading

• Stolt-Nielsen Crew Review — what working on chemical tankers actually looks like
• Lithium-Ion Batteries — batteries shipped in bulk may fall within HNS definitions
• UK ETS — HNS and ETS are the two most significant regulatory changes this decade
• Decarbonisation Careers — the converging regulatory framework and what it means for your career
• Seafarer Rights MLC 2006 — your rights when carrying dangerous goods and something goes wrong