Introduction There has been a rapid proliferation in the development of new chemical compounds and their extensive use. Over 11 million chemical substances are known and some 60,000 to 70,000 chemicals are in regular use. Of those, approximately 3,000 account for 90 per cent of total commercial and other uses. On average, three new chemicals are licensed for commercial use each day. Only a fraction of chemicals in use have adequate toxicological data.Large amounts of different types of dangerous substances, materials and articles (dangerous goods - DG) are present in communities around the world. They are also present in transit via highways, railways, waterways, air and pipelines. Dangerous goods/cargoes are carried by water in bulk (e.g. oil, oil products, liquefied gases and some chemicals) and packaged form (hereinafter packaged dangerous goods - PDG). Ships with large quantities of many different types of PDG penetrate estuaries, harbours and narrow channels to take them through or into large centers of population. Between 10-15 per cent of cargoes carried by water are PDG. Dangerous goods are also carried in ‘limited quantities’, for example in the form of passengers’ personal effects, on board passenger (cruise) and ferry ships. The principal international rules for the carriage of PDG by sea are set in the International Maritime Dangerous Goods (IMDG) Code, which has been harmonized with the ‘United Nations Recommendations on the Transport of Dangerous Goods’ and other modal regulations.A large proportion of accidents involving dangerous goods, in many cases with fatal consequences and severe damage to the environment, happen during transportation. The review of many accident case histories has shown that ships carrying PDG are, in many cases, involved in serious and very serious marine accidents in which many people have been killed, injured and suffered ill health. Many ships have been totally lost with dangerous cargoes on board in coastal and sensitive areas. On average, 230 ships with a gross registered tonnage of 1.1 million are lost worldwide every year. In addition, every year many PDG are lost overboard. Miles of beaches have been sealed for many days and thousands of people have been engaged in costly recovery or cleaning up operations.