The Antarctic Treaty area includes over 20 million square kilometres of the Southern Ocean, extending from the Antarctic coast to 60 degrees South latitude. On the initiative of the ATCM the International Maritime Organization (IMO) in 1990 designated these waters a “Special Area” (where the adoption of special mandatory methods for the prevention of sea pollution is required) under the International Convention for the Prevention of Pollution from Ships (Marpol 73/78).
Annex IV to the Environment Protocol prohibits discharge of oil, noxious liquid substances and garbage in the Antarctic Treaty area. It also contains rules for the discharge of sewage; and for ship retention capacity; reception facilities; sovereign immunity; preventive measures; and emergency preparedness and response.
In 2005 the 28th ATCM requested the IMO to examine mechanisms for restricting the use of Heavy Fuel Oil in Antarctic waters, acknowledging the potential for fuel spills in the Antarctic Treaty area due to operational risks such as icebergs, sea ice, uncharted waters, and the high potential for environmental impacts should a spill occur. In 2006 the 29th ATCM adopted Practical Guidelines for Ballast Water Exchange in Antarctic waters, which were subsequently adopted by the IMO.