The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) was formed in 1996 to prohibit any and every kind of nuclear weapon testing. As the name suggests, the treaty was formed to bring an end to unchecked nuclear weapons test explosions. The treaty prohibited testing of nuclear weapons or similar nuclear explosions in outer space, atmosphere, or under water.

The treaty allows nuclear tests to be carried underground provided no radioactive debris falls outside borders of the member country carrying out the test. Countries signing and ratifying the treaty should work towards full disarmament, and must end the armaments race and environment contamination courtesy radioactive substances. The treaty was established to promote international security and peace.


Though opened for signature in 1996, the talks relating to the treaty have been on much before. Representatives of Great Britain, the United States and Soviet Union authenticated the Limited Test Ban Treaty on August 5, 1963. China and France were invited to sign the treaty then but they refused. The treaty was the first crucial step towards controlling nuclear weapon development and testing.

Discussions about such a treaty began a decade earlier between the three nations during the 1950s. The inspiration for the treaty came from the rising, dangerous nuclear arms race trend back then and also the opposition from the public for nuclear weapons’ atmospheric testing. The limited treaty would have come into effect in 1960, if not for the American spy plane’s downing above Soviet Union territories in May, 1960.

Entry into Force

CTBTO is headquartered in Vienna, Austria and 183 nations (as of June, 2016) have signed the CTBTO, of which 164 have ratified the treaty. Signing the treaty means being in approval of the treaty’s principles; ratification is adhering to or implementing those principles. The treaty isn’t a law yet and violating member states therefore cannot be prosecuted. Also, members can leave the CTBTO if they believe the extraordinary events relating to the treaty’s subject matter is in conflict with their national interests.

For the treaty to come into force (according to CTBTO’s Article XIV), it would need ratification from the 44 Annex 2 states. These are countries that have nuclear energy or research reactors, and were a part of the formal 1996 Conference on Disarmament session. According to NGOs, it is vital CTBTO enters into force as soon as possible to mitigate nuclear proliferation at the earliest.

The treaty doesn’t have a specific tenure and is expected to last for an indefinite period. Once the treaty enters into force, a review conference can be convened once every decade, to usually consider possibilities of allowing underground nuclear explosions with peaceful objectives. Former U.S. president Bill Clinton was the first global leader to authorize the treaty.

Compliance Measures

To make sure member countries comply with the treaty, CTBTO has a verification regime in place. However, this regime can be implemented only once the treaty enters into force. The regime comprises:

International Monitoring System (IMS)

IMS has 321 monitoring stations along with 16 laboratories across the globe. These are used to monitor Earth for any nuclear explosion sign. For verification, IMS uses the following methods: seismic, hydroacoustic, infrasound and radionuclide. Seismic, hydroacoustic, and infrasound stations take care of monitoring the underground, large oceans and atmosphere, respectively. Radionuclide stations unearth radioactive debris resulting from underwater or underground nuclear explosions, atmospheric explosions. These stations are spread across 89 countries across the globe, with most of them situated in inaccessible and remote regions. The CTBTO foots their establishment and operational expenses.

International Data Centre (IDC)

The IDC supports the IMS by processing and analyzing information recorded at monitoring stations. Located at Vienna, Austria, the IDC makes data bulletins, which are forwarded to CTBTO members for their assessment and judgment. The incoming information is registered, located and analyzed with major focus on nuclear explosion detection.

Global Communications Infrastructure (GCI)

The GCI transmits recorded information to the IDC. The information is received and distributed via a six-satellite network. These satellites direct the transmissions to the three ground-based hubs, and the information is then sent by terrestrial links to the IDC.

Consultation and Clarification

The consultation and clarification aspect entails resolving and clarifying any matter raised by a member state, such as specific information collected containing a nuclear explosion. The questioning member state can interact directly with the state under question or take the matter through the executive council. The member state may also request CTBTO Director-General for information. The state that’s being questioned has 48 hours for clarifying the problem.

On-Site Inspections (OSI)

Member states, if they wish, can request to inspect sites of any other CTBTO member state, irrespective of whether the consultation and clarification was satisfactory or not. Such inspections are considered final verification measures.

Confidence-Building Measures

Member states can voluntarily notify CTBTO if any chemical explosion entailing blasting material (300 tonnes or more) happened on their territories. Such voluntary submissions help resolve data misinterpretation. For example, a huge mining explosion can be misinterpreted for a nuclear explosion.