Lloyd’s Register has warned of a marked deterioration in marine fuel quality during the second half of 2025, with December recording the highest number of off-specification cases for the year.

The organisation’s Fuel Oil Bunker Analysis and Advisory Service (FOBAS) report covering July to December 2025 highlights a concentration of repeated fuel quality failures across major bunkering hubs, including Singapore, Rotterdam, Antwerp, Hong Kong and Port Klang.

According to the analysis, the surge in December was driven by recurring problems such as elevated sulphur content, extreme catalytic fines, high sediment levels and excessive water contamination.

Distillate fuels also continued to present risks. The report recorded repeated flash point failures in ports including Civitavecchia, Lisbon, Palermo and Lianyungang, with several samples measuring between 47°C and 55°C, below the SOLAS minimum requirement of 60°C. Some cases were linked to land-grade diesel entering the marine supply chain.

Murray Kirkwood, fuel specialist consultant at Lloyd’s Register, said: “The clustering of off-specification events towards the end of 2025 demonstrates the ongoing volatility of the global marine fuel supply chain. While many fuels continue to meet specification, the scale and severity of late-year incidents leave little margin for error and reinforce the need for conservative fuel handling, robust testing regimes and proactive onboard management.”

The H2 2025 report builds on Lloyd’s Register’s earlier first-half analysis, providing updated data and new case studies showing how fuel quality trends are evolving amid tighter environmental regulation and changing fuel formulations, including full enforcement of the Mediterranean Sulphur Emission Control Area.

Looking ahead to 2026, the organisation warned that operators will face a more complex fuel landscape as the EU Emissions Trading System expands and FuelEU Maritime requirements take effect. With increasing use of new feedstocks, biofuel blends and alternative fuels, Lloyd’s Register said consistent sampling, testing and onboard fuel management will become even more critical.

The FOBAS H2 2025 Fuel Quality Report is available from Lloyd’s Register.