International Convention for the Prevention of Pollution from Ships

IMO has categorized noxious liquid substances in different categories with corresponding discharge limits. A complete list of noxious liquid substances is listed in the International Bulk Chemical Code (IBC) book, which classifies various liquids in terms of what level of hazard they pose to marine life and people if discharged into the sea. Check the MARPOL rules before discharging anything into the water.

Standards exist for packing, labeling, documenting, stowing and limiting quantity of harmful substances. A list of substances that are classified as marine pollutants can be found in the International Maritime Dangerous Goods (IMDG) code. Accidental loss overboard of containers, especially those which are known to contain marine pollutants, must be always reported to shore authorities.

The regulations in Annex IV of MARPOL allow the discharge of sewage into the sea when the sewage has been treated by an approved sewage treatment plant (STP). Such plants collect the sewage and treat it (either chemically or biologically) so it can be discharged either at sea or in an onshore facility. Untreated sewage can only be discharged when certain conditions are met, including a certain distance from the nearest land.

It is illegal to discharge any solid materials other than certain types of food and animal waste anywhere at sea. Solid waste, including plastics, should be taken to a reception facility while the ship is in port. Review the MARPOL regulations, the vessel’s Garbage Management Plan or the placard in the garbage storage area of your ship for specific instructions.

In the last decades, IMO has been actively working at regulating the emission of polluting air substances by ships. The international air pollution requirements establish limits on nitrogen oxides (NOx) emissions and require the use of fuel with lower sulfur content or the use of scrubbers. More stringent requirements apply to vessels operating in Emission Control Areas (ECAs) such as the North American ECA that includes U.S. waters as well as ships operating within 200 nautical miles of the coast of North America. The IMO has developed a package of measures for reducing shipping’s CO2 emissions and aims to cut carbon dioxide emissions in half (compared to 2008) by 2050. 

The ‘International Convention on the Control of Harmful Anti-Fouling Systems on Ships’ prohibits the use of harmful organotin (organic compounds containing tin) in anti-fouling paints used on ships and creates a possibility to prevent the potential future use of other harmful substances in anti-fouling systems. 

The regulations for management of ships’ ballast water are described in the International Convention for the Control and Management of Ships’ Ballast Water and Sediments. The Convention requires all ships to carry out ballast water management procedures to avoid the transfer of invasive species. Procedures include ballast water exchange (a temporary measure) and ballast water treatment.

The IMO Convention on Safe and Environmentally Sound Ship Recycling contains guidelines for human and environmentally friendly recycling of ships. It was agreed upon in Hong Kong in May 2009 but has not entered into force yet. When in force, every ship must have a list of all materials present on board that may be hazardous to man and nature, including materials present in the ship’s structure, systems and equipment. Ship owners are responsible for maintaining and updating this IHM (Inventory of Hazardous Materials) throughout the life of the ship. 

Seafarers are especially entrusted with stewardship of the oceans. For regulations to be effective, the people working in the shipping are very important. Compliance with MARPOL regulations, when combined with accurate documentation, thorough training, and proper contingency planning will help marine organizations stay proactive in environmental preservation. The environmental performance of the shipping industry always depends on the professionalism and competence of its people, on ships and on shore.