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CTBTO -Comprehensive Test-Ban Treaty Organization

The CTBTO aims to prepare for the entry into force of the Comprehensive Test-Ban Treaty (CTBT) of 1996. Under the CTBT, States Parties undertake not to conduct nuclear tests or any other types of nuclear explosions.

A provisional technical secretariat, PTS, is responsible for the establishment of an international monitoring system (using seismic, hydroacoustic, infrared and radionuclide measurements). Denmark hosts an infrared and a seismic station, both located in Greenland.

The Treaty has not yet entered into force, as it has to be ratified by 44 named nuclear technology holder countries. Of these, eight are still missing. Denmark ratified the treaty in 1998, and all EU countries have ratified it, as have an overwhelming majority of other countries.

The CTBTO's verification system has proven its effectiveness with regard to the North Korean nuclear tests. In addition, the system is used for a variety of civil and scientific purposes, e.g. tsunami and earthquake warning.

You can read more about the CTBTO here.