In General Resolution A/42/37C (1987), the UN General Assembly established the UN Secretary General’s Mechanism (UNSGM) to carry out investigations in response to allegations of possible chemical, biological and toxin weapons that may constitute a violation of the 1925 Geneva Protocol or other international law. The Guidelines and Procedures for the usage of such a mechanism were established in 1989 by the UN General Assembly document A/44/561. In 2007, the Office for Disarmament Affairs (UNODA) organized a group of experts to discuss and suggest updates to the 1989 guidelines and procedures for the UNSGM. The expert group prepared a set of updated appendices that focus on the relevant guidelines, procedures, and technical aspects of an investigation into the alleged use of a chemical, biological, or toxin weapon. The appendices cover, inter alia, the type of information to be provided by a Member State in the reporting of a possible chemical, biological, or toxin (CBT) weapon attack to UN Secretary General; the type of information to be provided when the Member States propose experts to assist the UN Secretary General; a list of areas of expertise; a list of equipment and supplies needed for an investigation; and the information that Member States need to provide when when proposing laboratories that may analyze samples. The appendices also include guidelines for interviewing witnesses/victims of a potential CBT weapon attack, pre-mission planning, protecting the confidentiality of the investigation, and reporting of investigation activities.