The carriers' intra-European and Transatlantic customers will be left with the biggest bill of all when the tightened requirements for ships' sulphur emissions are implemented on January 1st 2015, says analysts Drewry, pointing out that a larger percentage of these ships' transit time will be spent in the so-called Sulphur Emission Control Areas (SECA) zones, which include the Baltic Sea, the North Sea, and within a 24 nautical mile coastal zone off California on the US West Coast, off Canada's East and West coasts, and parts of the Caribbean.