The only area where incinerator cannot operate is ports, harbours, and estuaries. An estuary is the wide part of the river that nears the sea.

The incinerator can be operated in SECA also but only outside the port limits.

There is no regulation that prohibits the ship to burn residues generated from HSFO in SECA.

As per MARPOL Annex VI, Regulation 16, the incineration is prohibited for

• residues of cargoes subject to Annex I, II or III or related contaminated packing materials;
• polychlorinated biphenyls (PCBs);
• garbage, as defined by Annex V, containing more than traces of heavy metals;
• refined petroleum products containing halogen compounds;
• sewage sludge and sludge oil either of which is not generated on board the ship; and
• exhaust gas cleaning system residues. 

Dont forget also that exist a prohibitation due to Elsinki Convention regarding the 

Incineration in Baltic Sea Area(SECA1-territorial waters)