Ultra Low Sulphur Fuel Oil
Abbreviation: ULSFO
Residual marine fuel with ≤ 0.10% sulphur, used to meet Emission Control Area limits.
In practice
Stored in dedicated fuel tanks where possible; mixing high- and low-sulphur fuels in ECA waters risks compliance breach. Mid-passage tank changeover follows the operator's SECA changeover procedure.
Regulatory detail & full definition
Ultra Low Sulphur Fuel Oil — residual marine fuel with sulphur content at or below 0.10% by mass, used to meet Emission Control Area requirements under MARPOL Annex VI Reg. 14. ULSFO emerged as a distinct product after the 2015 ECA tightening because the alternative — switching to MGO (DMA) at the ECA boundary — was costly. ULSFO is typically produced from low-sulphur crudes by hydrotreatment or selective blending. The fuel must still meet ISO 8217 viscosity and stability criteria and is normally listed as RMG 100 or similar.
Authoritative source: MARPOL Annex VI (Air pollution) ↗
Related
Source: MARPOL Annex VI Reg. 14
High confidence
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