II. Methodological Considerations

6. In its investigation of the alleged use of chemical weapons in the Ghouta are of Damascus on 21 August 2013, the Mission visited Moadamiyah on 26 August 2013 and Ein Tarma and Zamalka on 28-29 August. During its on-site visits, the UN Mission carried out the following activities:

- Interviews with survivors and other witnesses;
- Documentation of munitions and their sub-components;
- Collection of environmental samples for subsequent analysis;
- Assessment of symptoms of survivors;
- Collection of hair, urine and blood samples for subsequent analysis;

7. Doing so, the Mission adhered to the most stringent protocols available for such an investigation. Key to investigation methods of alleged use of chemical weapons are concepts like traceability, documentation, use of standardized and recognized procedures as well as relevant and up-to-date training of inspectors.

8. Traceability means that all processes and procedures are recorded and continuity is maintained for transparency and to withstand future scrutiny.

9. For example, the chain of custody procedures for sampling involved the following: The retrieval of samples is recorded and witnessed, samples are sealed, detailed documentation is prepared, transported to the preparatory laboratory under supervision of the members of the Mission, seals are confirmed and then broken, and the samples are representatively subdivided. The re-sealed samples are then distributed to the OPCW-designated laboratories with guidance documents, again, under the same supervision. The laboratories conduct their activities using standardized procedures (including quality assurance/quality control checks) for receiving, storing, and analyzing samples. The results are then returned under supervision to the investigation Mission for review. Each transfer of material is accompanied by handover receipts.

10. All information received, be it witness statements, pictures, videos, audios or patient records and other documentation, is recorded and registered for filing and archiving with the United Nations.

11. Methods for interviews, sampling, and documentation follow well established standard operating procedures (SOPs), developed and enforced by the OPCW and the WHO and in accordance with the Guidelines.

12. Mission members are regularly trained and periodically updated on aspects of their respective specializations, including risk assessments, epidemiology, sampling, scene assessment, acquisition and processing of bio-medical samples, the performance of interviews, munition designs, unexploded ordinances, epidemiology as well as safety and security.

13. The selection process used was designed to primarily identify survivors who had severe clinical presentations, since these were also expected to have had significant exposure to the chemical agent. The ability to provide a sound history of the event and identify the alleged impact sites was also considered in selecting survivors.

14. The selection process was guided by a standardized checklist that aimed to identify individuals who either demonstrated moderate to severe symptoms and signs, or were able to provide a clear and detailed history of the event. These survivors were requested to present to the local hospital on the day of the field visit to meet with the investigation Mission. Physicians at Zamalka were also asked to provide a purposive sample of eight medical records of patients with significant symptoms and signs.