Secretary-General’s Mechanism for Investigation of Alleged Use of Chemical and Biological Weapons (UNSGM)


With resolution A/42/37 C (1987) the UN General Assembly established, and the Security Council reaffirmed with resolution 620 (1988), the Secretary-General’s Mechanism (UNSGM) to carry out prompt investigations in response to allegations of the possible use of chemical and bacteriological (biological) and toxin weapons that may constitute a violation of the 1925 Geneva Protocol or other relevant rules of customary international law. If any Member State provides the Secretary-General with a report of such allegations, the Secretary-General is authorized to launch an investigation to ascertain in an objective and scientific manner the facts of the matter, including dispatching a fact-finding team to the site(s) of the alleged incident(s), and to report the results of the investigation to all Member States. The UNSGM is not a standing investigative body. Instead, Member States nominate expert consultants, qualified experts and analytical laboratories which are then listed in a roster and may be called upon to support a UNSGM investigation and in accordance with the Guidelines and Procedures endorsed by the General Assembly in resolution A/45/57C (1990).

The Office for Disarmament Affairs (UNODA) organized, in 2007, a group of experts to discuss an update of the 1989 Guidelines and Procedures. Recognizing that a broad review process would necessarily entail the direct involvement of Member States, the group prepared updates to the Appendices associated with the guidelines and procedures, in particular taking into account the developments in the biological area. The updated Appendices focus on relevant technical biological aspects of investigation of alleged use.

With respect to chemical weapons, the Organisation for the Prohibition of Chemical Weapons (OPCW) was established in 1997 to implement the Chemical Weapons Convention (CWC). Since then, the OPCW is responsible for investigations of alleged use of chemical weapons, except for investigations related to countries that are not a party to the Convention. In such cases, the Secretary-General should cooperate with the organs provided for in the CWC in carrying out investigations in accordance with the Guidelines and Procedures for the UNSGM (A/44/561) and the relevant provisions of the CWC.

For the Biological Weapons Convention (BWC), there is no equivalent implementing agency, and thus the UNSGM, which is distinct and independent from the BWC, is the only international mechanism to investigate the alleged use of biological weapons. As such, UNODA’s efforts in recent years to strengthen the readiness of the UNSGM have focused on biological weapons events.

In 2018, the Secretary-General released his Disarmament Agenda, “Securing Our Common Future.” Under the guiding statement “Ensuring Respect for Norms Against Chemical and Biological Weapons,” Action 10 of the Agenda addresses the readiness of the United Nations to investigate alleged use of biological weapons through the UNSGM.


As custodian of the UNSGM, UNODA is tasked with ensuring the operational readiness to carry out a mission in response to reports from Member States. To this effect, UNODA maintains the rosters of experts and analytical laboratories, coordinates on training activities with partners, including Member States, laboratories and international organizations and conducts outreach activities.

UNODA also coordinates with the UN Internal Task Force (UNITF), which is composed of points of contacts to the UNSGM from various departments in the UN Secretariat and other UN entities that will be critical for the successful implementation of a mission in response to a request from Member States.

Nominated Experts and Laboratories

In accordance with the Guidelines and Procedures, experts and laboratories nominated by Member States would be requested to provide assistance and service at a short notice when the UNSGM is activated.

UNODA regularly sends a Note Verbale to all Member States (via the Mission in New York) to request the nomination of experts and laboratories for the UNSGM roster. However, Member States can submit nominations at any time. The most recent Note Verbale can be found here.

The current status of nominations of qualified experts, expert consultants, and analytical laboratories is provided below.

Qualified ExpertsExpert ConsultantsAnalytical Laboratories
Qualified experts may be called upon to actively participate in any investigation team to conduct investigations into the alleged use of CBT weapons as requested by the Secretary-General. Their roles are outlined in the Guidelines and Procedures (A/44/561), paragraphs 64-75.Expert consultants may be requested to advise and assist in the overall conduct and operation of the UNSGM, from planning and deployment to operation and reporting. Their roles are outlined in the Guidelines and Procedures (A/44/561), paragraphs 57-63.Analytical laboratories may be requested to test for the presence of CBT agents. The role of designated analytical laboratories is outlined in the Guidelines and Procedures (A/44/561), paragraphs 76-80.

Nominations of Qualified Experts, Expert Consultants, and Analytical Laboratories (as of May 2024)

To contact the UNODA team in support of the UNSGM, please email: