A/HRC/36/55 sarin (binary synthesis shortly before use without subsequent purification of the agent for long-term storage). 28. The Commission has independently gathered extensive information which, in the aggregate, strongly supports the claim that the victims were exposed to sarin or a sarin-like substance. Apart from the fact that none of the victims was observed to have wounds or visible injuries, the symptoms reported are consistent with those suffered by persons exposed to an organophosphorus chemical such as sarin. Those include: foaming from the mouth and nose, contracted pupils, respiratory difficulties, coughing, blue lips, pale or yellow skin, loss of consciousness, dizziness, convulsions, vomiting, paralysis, and diminished heartbeat. First-responders and medical staff recalled suffering from headaches, nausea, congested chests, and blurred vision after treating patients. Five weeks after 4 April, at least four interviewees were still experiencing some of these symptoms. 29. Most of the interviewees at the scene when the agent cloud was released or who arrived on location shortly thereafter stated they did not notice any particular smell, which is consistent with the fact that sarin is odourless. Some interviewees, however, reported a “bad smell”. One interviewee described it as similar to drainage or waste water, while another said it resembled a strong insecticide. It should be noted that there is a fair degree of variability in the sensitivity of humans to smell, so such discrepancies are not unusual. It is also apparent from the analytical results of the environmental samples that the agent released into the atmosphere contained a number of impurities (several phosphor-organic compounds, hexamine, fluorinated compounds), which would explain the insecticide-like or otherwise bad smell perceived by some witnesses. VII. Findings 30. The extensive body of information gathered by the Commission indicates that a Syrian Su-22 conducted four airstrikes in Khan Shaykhun at approximately 6.45 a.m. on 4 April. Photographs of remnants taken at the sites along with satellite imagery corroborate eyewitness testimony identifying the impact points of the four aerial bombs. Eyewitnesses and early warning reports identified the aircraft as a Su-22, which only the Syrian air force operates. 31. The Commission identified three of the bombs as likely OFAB-100-120 and one as a chemical bomb. Interviewees consistently stated that this latter bomb produced less noise and less smoke than the other three, and that it released a gas which spread over a distance between 300 and 600 meters. Photographs of remnants provided to the Commission by interviewees further indicate an aerial chemical bomb was employed. Further, weather conditions at 6.45 a.m. on 4 April were ideal for delivering a chemical weapon. The wind speed was just over three kilometres per hour, with no rain and practically no cloud cover. Under such conditions, the agent cloud would have drifted slowly downhill following the terrain features at the location (roads and open spaces), in a southerly and westerly direction. 32. At least 83 persons, including 28 children and 23 women, were killed, and an additional 293 persons including 103 children were injured after being exposed to gas released by the chemical bomb. Based on bio-medical samples obtained during autopsies and from individuals undergoing treatment in a neighbouring country, the OPCW FFM found that these individuals were exposed to sarin or a sarin-like substance. Information gathered by the Commission from victims, eyewitnesses, and medical personnel on the symptoms suffered by victims is also consistent with exposure to sarin. None of the victims had wounds or visible injuries, and all experienced a combination of the following symptoms: foaming from the mouth and nose, contracted pupils, respiratory difficulties, coughing, blue lips, pale or yellow skin, loss of consciousness, dizziness, convulsions, vomiting, paralysis, and diminished heartbeat. November 2013. This EOI listed chemicals from the declared Syrian chemical weapon stockpile and included binary chemical weapons components as well as 80 metric tonnes of hexamine. 28