SECA, Sulphur Emission Control Area

A SECA (Sulphur Emission Control Area), formally an ECA under MARPOL Annex VI Reg.14, caps fuel sulfur at 0.10% m/m inside its boundary against the 0.50% global cap. The designated areas are the Baltic Sea, the North Sea, the North American area, the US Caribbean, and the Mediterranean Sea from 1 May 2025. Inside a SECA a ship burns compliant low-sulfur fuel or runs an approved scrubber; the changeover time and tank are logged. NECAs add a NOx Tier III limit in the same or overlapping areas.