The Convention was called for by the United Nations Conference on the Human Environment (June 1972, Stockholm), the treaty was drafted at the Intergovernmental Conference on the Convention on the Dumping of Wastes at Sea (13 November 1972, London) and it was opened for signature on 29 December 1972. It entered into force on 30 August 1975 when 15 nations ratified. As of 1 October 2001, there were 78 Contracting Parties to the Convention. International Administration of the Convention functions through Consultative Meetings held at International Maritime Organization (IMO) headquarters in London.