One of the most sensitive issues in shipping today is the carriage of dangerous cargoes and potentially polluting cargoes. For many years the major maritime nations have required specific action by all those concerned with the movement of dangerous goods both on land and afloat. The International Maritime Organisation (IMO) is the arm of the United Nations which is responsible for formulating International Maritime Law especially in the areas of safety, pollution, environmental protection and exploitation. Its headquarters are in London. The international carriage of dangerous and maritime polluting goods is governed by the IMO International Maritime Dangerous Goods Code (IMDG Code). These rules supplement any local national rules that apply, to the extent that they represent the minimum standards that must be adopted. In some countries there are national regulations (or local port rules) that have more stringent requirements and the ship manager must be fully aware of any variations applying to cargoes in transit as well as being loaded or discharged at ports in the vessels itinerary. Most countries also apply similar laws on shore to the producer who is required to label anything containing dangerous goods, and to complete documentation which specifies the nature and hazards of the goods when they are on the move by any form of transport. The stowage of these dangerous goods requires special consideration, as will be explained below. The I.M.O. INTERNATIONAL MARITIME DANGEROUS GOODS CODE (‘THE BLUE BOOK’ or IMDG Code) has been published, in loose-leaf form, in five volumes; this publication is updated as and when required. This is usually when a hazard occurs which has not happened before, or a new substance comes onto the market. Local additions or modifications to the Maritime Rules are often made by individual governments and published as Notices to Mariners.