(1) A four-category system of categorisation for NLSs (categories X, Y, Z and Other Substances) replaces the old five-category system (categories A, B, C, D and Appendix III).
For ships built on or after 1 January 2007 the maximum permitted residue in a tank and its associated piping left after discharge is set at a maximum of 75 litres for products in categories X, Y and Z (whereas under the old Annex II it was 100 or 300 litres, depending on the category). (2) No special areas are designated by the revised Annex II, whereas the old Annex II designated three (the Baltic Sea area, the Black Sea area and the Antarctic area). Discharges of NLSs in the Antarctic area (i. e. the sea area south of 60° south) are prohibited under regulation 13.
