Industry Issues

Vessel Discharges

Large commercial vessels routinely discharge ballast water, gray and black water, bilge water, and other discharges incidental to normal vessel operations and consistent with international and national standards. Ballast water discharges are a concern due to their potential to transfer aquatic invasive species from one location to another with consequent changes in regional and local ecosystems. Hull fouling, which is another potential vector for the transfer of aquatic invasive species that also reduces the efficiency of the vessel as it moves through the water, is managed through the use of anti-fouling systems. Sewage, gray water and other discharges are regulated to prevent environmental damage while facilitating safe and efficient vessel operation. Accidental spills of oil and fuel can also cause significant damage to the environment and extensive standards have been put in place to prevent such accidents and to respond to such incidents when they do occur. See SPILL PREVENTION & RESPONSE below for more information. Shipboard management of garbage and other wastes generated on board vessels is addressed under Recycling, Reuse, and Waste Management.

Sewage, Gray water, and Other Discharges

Discharges of sewage (also known as black water) and gray water, which is the effluent generated from wash basins and showers on board ships, are regulated under MARPOL Annex IV as well as through specific restrictions established through national and local laws. Learn more

Ballast Water

The Members of the World Shipping Council actively support an effective solution for managing ballast water discharges from vessels so as to minimize the environmental risk they present as a pathway for the transfer of aquatic invasive species. The WSC has long advocated for environmentally protective and economically achievable international standards for the treatment of ship's ballast water. Learn More

Spill Prevention & Response

International regulations for the prevention of oil pollution are set out in Annex I to MARPOL as well as the International Convention on Oil Pollution, Preparedness, Response, and Cooperation (OPRC) and its protocol covering pollution by hazardous and noxious substances (HPRC). To learn more, visit, and select Marine Environment, Prevention of Pollution.

Antifouling Compounds

All ocean-going commercial vessels utilize hull coatings designed to minimize resistance to movement through the water and the attachment of both soft and hard-shell organisms. These coatings are often referred to as "antifouling" coatings and are critical since they play a very important role in minimizing fuel consumption with a consequent reduction in CO2 emissions.

Some compounds employ "foul-release" coatings that are extremely slick and release fouling organisms as a vessel obtains specified operating speeds. Other compounds employ a self-polishing paint matrix that provides for a controlled release of specific biocides devoted to preventing the attachment of specific fouling organisms such as barnacles and slime.

Standards for the manufacture and use of these biocidal products are established through national regulations. In addition, the International Convention for the Control of Harmful Anti-fouling Systems on Ships (often referred to as the AFS Treaty) prohibits the use of organotins as an active antifouling agent and sets forth a structure for international restrictions on other antifouling compounds deemed to be harmful to the marine environment. The AFS Treaty eliminated the use of tributyltin (TBT) on ships in 2008 due its persistence in the marine environment and its effect on non-target species. To learn more, visit and select Marine Environment, Anti-Fouling Systems.