Because merchant shipping is so fundamentally international, the maritime nations have found that a high degree of self-regulation is essential. This is effected by appropriate international bodies reaching agreement as to the content of a proposed convention which is offered for adoption. States who support the convention duly sign it, this is known as ratification. Usually the convention itself provides that a certain minimum number of states must ratify the convention before it can come into force. Once the convention has been ratified by a sufficient number of countries for it to enter into force, individual countries must adopt the convention into their own national laws to give it full force. How this happens will differ from country to country. In England, the relevant convention must be incorporated into a statute, be placed before Parliament and then, duly enacted. In addition to these self-regulating procedures, some international regulation is imposed upon the shipping community. These can be unilateral, as in the case of the Oil Pollution regulations enacted by the United States (OPA90) or international as in the case of the Untied Nations Conference on Trade and Development (UNCTAD) which speaks principally for the less-developed non-maritime nations. The European Union is, of course, in a position to impose regulation both on EU member states and more internationally where appropriate. The IMO is a United Nations agency with its headquarters in London and is one of the most prolific producer of international shipping conventions. It began in 1948 as the Inter-governmental Maritime Consultative Organization and changed to its present name in 1982. Its two principal areas of operation are in Safety and Environment Protection.