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Facility Agreements

What is a facility agreement?

A facility agreement is a legal arrangement between the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) and each Member State that hosts an International Monitoring System (IMS) facility. The IMS is a global network of facilities  established by the CTBTO to monitor underground, the oceans and the atmosphere for evidence of a nuclear explosion. 

A nuclear explosion emits different signals and radionuclides that can be detected from a distance.

Why are they important?

Facility agreements help to address the entire bandwidth of issues regarding IMS facilities between the hosting Member States and the CTBTO:

Political aspects: By representing the formal commitment of a Member State to host the facility and cooperate with the CTBTO during the preparatory phase, the facility agreement helps to secure the collaboration of all relevant institutions at the national level for the installation and operation of the stations. By signing facility agreements, Member States agree to cooperate with the CTBTO in establishing, testing, operating, upgrading and maintaining IMS facilities, even before the Comprehensive Nuclear-Test-Ban Treaty (CTBT) has entered into force.

Legal aspects: The CTBT stipulates that while IMS stations are owned and operated by the hosting State, they are under the authority of the CTBTO (meaning that they must adhere to regulations laid out in the CTBT and developed further by the CTBTO). Issues such as ownership transfer, the conclusion of subsidiary arrangements with local operators, and granting the necessary privileges and immunities to the CTBTO and its officials are provided for in facility agreements.

Technological aspects: In order for the IMS to operate reliably, all facilities have to work in accordance with the requirements and procedures agreed on by the Treaty negotiators for the respective verification technologies (seismology, infrasound, hydroacoustics and radionuclide monitoring). Under facility agreements, the host State undertakes to test, operate and maintain the facility, as well as to provide utilities and transmit monitoring data to the International Data Centre (IDC) at the CTBTO’s headquarters in Vienna, in accordance with requirements and procedures.

Operational aspects: Facility agreements help ensure coordination between the CTBTO and countries hosting IMS facilities with regard to technical visits by CTBTO staff, access to the station, the cooperation of local entities, assistance with imports and exports, notification and solving of problems, and the physical security of the facility.

How many facility agreements need to be signed?

According to the CTBT, a facility agreement needs to be concluded with each of the 89 States hosting IMS facilities. As of 2025, facility agreements with 41 Member States (jointly hosting around 50% of all IMS facilities) have entered into force, while 8 more (another 8% of IMS facilities) have already been signed. Forty Member States (representing 44% of all IMS facilities) have yet to sign a facility agreement. 

Status of Facility Agreements

Host StateSignatureEntry into force
Argentina09-DEC-199902-MAR-2004
Armenia07-SEPT-201607-MAR-2017
Australia13-MAR-200017-AUG-2000
Austria17-SEP-201317-SEP-2013
Bangladesh  
Bolivia  
Botswana  
Brazil  
Cameroon16-NOV-2006 
Canada19-OCT-199819-OCT-1998
Cabo Verde23-NOV-2006 
Central African Republic23-DEC-201031-DEC-2010
Chile21-FEB-2014 
China  
Colombia  
Cook Islands14-APR-200014-APR-2000
Costa Rica  
Côte d’Ivoire  
Czech Republic13-NOV-200229-JAN-2004
Denmark  
Djibouti  
Ecuador24-FEB-2015 
Egypt  
Ethiopia  
Fiji  
Finland12-MAY-200006-JUN-2000
France13-JUL-200101-MAY-2004
Gabon  
Germany  
Greece  
Guatemala26-NOV-200202-JUN-2005
Iceland13-OCT-200526-JAN-2006
Indonesia  
Iran  
Israel23-SEP-200420-FEB-2014
Italy29-MAR-2006 
Japan  
Jordan11-NOV-199911-NOV-1999
Kazakhstan09-SEP-200405-DEC-2008
Kenya29-OCT-199929-OCT-1999
Kiribati  
Kuwait17-SEP-201315-NOV-2016
Kyrgyzstan  
Libya  
Madagascar  
Malaysia  
Mali  
Mauritania17-SEP-200317-SEP-2003
Mexico20-OCT-201120-OCT-2011
Mongolia05-JUN-200025-MAY-2001
Morocco  
Namibia01-APR-200901-APR-2009
Nepal  
New Zealand13-NOV-199819-DEC-2000
Niger24-NOV-200024-NOV-2000
Norway10-JUN-200210-JUN-2002
Oman19-MAY-2004 
Pakistan  
Palau29-APR-200229-APR-2002
Panama26-NOV-200326-NOV-2003
Papua New Guinea  
Paraguay4-APR-200327-JAN-2006
Peru14-MAR-200108-JUL-2002
Philippines14-APR-200308-JAN-2004
Portugal17-FEB-2011 
Republic of Korea  
Romania13-JUN-200313-OCT-2004
Russian Federation22-MAR-200527-DEC-2006
Samoa  
Saudi Arabia  
Senegal22-MAY-200124-MAR-2006
Solomon Islands  
South Africa20-MAY-199920-MAY-1999
Spain14-SEP-200012-DEC-2003
Sri Lanka14-JUN-2000 
Sweden  
Switzerland  
Thailand  
Tunisia11-NOV-201114-FEB-2014
Türkiye  
Turkmenistan12-DEC-201528-DEC-2015
Uganda15-JUN-201215-JUN-2012
Ukraine27-SEP-199920-APR-2001
United Kingdom12-NOV-199916-JUN-2004
United Republic of Tanzania10-DEC-200710-DEC-2007
United States of America  
Venezuela  
Zambia20-OCT-200120-OCT-2001
Zimbabwe