The limitations on the sulphur content of certain petroleum-derived liquid fuels as laid down in this Directive shall not, however, apply to:
(a) - petroleum derived liquid fuels used by seagoing ships, except those fuels falling within the definition in Article 2(3),
- marine gas oil used by ships crossing a frontier between a third country and a Member State;
(b) fuels intended for processing prior to final combustion;
(c) fuels to be processed in the refining industry.