The 2010 HNS Convention: Closing a Major Gap in Maritime Liability and Compensation Introduction For decades, the international maritime liability framework has included established liability and compensation arrangements addressing oil pollution, bunker pollution and wreck removal. One significant gap, however, has remained: damage arising from incidents involving hazardous and noxious substances carried by sea. That gap is now set to close. On 29 November 2027, the International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances by Sea, 1996, as amended by the 2010 Protocol, commonly known as the 2010 HNS Convention, will enter into force. It will introduce the first dedicated international liability and compensation regime for damage arising in connection with the carriage of hazardous and noxious substances (HNS) by sea. Until now, damage arising from hazardous cargo incidents has often been addressed through national laws, contractual arrangements and general maritime liability regimes. The Convention introduces a more structured and uniform framework for qualifying claims, and represents a significant step towards a more complete international liability and compensation framework. Why now? The Convention’s entry into force follows the fulfilment of all treaty conditions in May 2026, triggering an 18‑month implementation period before it enters into force on 29 November 2027. This development closes a long-recognised gap in the international maritime liability framework and comes at a time when increasing volumes of chemicals, liquefied gases and substances also used as alternative fuels are being transported by sea.    Key takeaway From 29 November 2027, the HNS Convention will provide a dedicated international framework for qualifying damage caused by HNS carried as cargo by sea. It combines strict shipowner liability and compulsory financial secu