A team of U.N. inspectors has found “clear and convincing evidence” that a chemical weapons attack using the nerve agent sarin killed a large number of civilians near Damascus on 21 August. Although the team’s report  does not discuss who was responsible for the attack, it includes information on the rockets used to deliver the sarin that some countries say implicates the Syrian government.
U.N. Secretary-General Ban Ki-moon, who received the report yesterday from team leader and Swedish scientist Åke Sellström, said today at a press conference: “The findings are beyond doubt and beyond the pale. This is a war crime. … It is the most significant confirmed use of chemical weapons against civilians since Saddam Hussein used them in Halabja in 1988,” an attack that killed at least 3200 Kurds. (U.S. officials say 1400 people died in the recent Syrian attack.) But Ban stopped short of assigning blame, saying that was not the mission of the U.N. team.
The group, which included experts  from the Organisation for the Prohibition of Chemical Weapons (OPCW) in The Hague, visited the Ghouta suburb of Damascus between 26 August and 29 August. Their 38-page report (including appendices) contains sections on environmental samples such as soil and swipes from rockets; interviews with more than 50 survivors and with medical staff members; and blood, urine, and hair samples from survivors. Chemical testing on the biological and environmental samples was done by four OPCW-designated labs in Finland, Germany, Sweden, and Switzerland.
The survivors’ symptoms, sometimes still evident up to a week after the attack, included those typical of exposure to organophosphates such as sarin: loss of consciousness, shortness of breath, and blurred vision, for example. Tests of biological samples from survivors showed “definitive evidence of exposure to sarin” for most. And the majority of environmental samples, including rocket fragments, tested positive for sarin or its degradation products.
The team’s conclusion: "Chemical weapons have been used in the ongoing conflict between the parties in the Syrian Arab Republic, also against civilians, including children, on a relatively large scale. In particular, the environmental, chemical and medical samples we have collected, provide clear and convincing evidence that surface-to-surface rockets containing the nerve agent sarin were used … in the Ghouta area of Damascus. This result leaves us with the deepest concern.”
The report’s appendices include drawings and photos of rockets used to deliver the sarin. At the press conference, ambassadors to the United Nations from the United Kingdom, the United States, and France said that these details, and others described by Sellström in a briefing to the U.N. Security Council this morning, reinforce their previous assertions that only the Syrian regime could have launched the attack. For example, a single warhead could hold 56 liters of nerve agent, a large amount; the quality of the sarin was higher than Saddam Hussein’s sarin; and the rocket type had apparently been used in the past by the regime but not by the Syrian rebels.
Ralf Trapp, an arms control expert in Chessenaz, France, says that he finds the combination of weapons evidence convincing, too, as well as the fact—noted in the U.N. inspector’s report—that the rockets were launched early on a morning when the air was moving toward the ground, which meant the gas sank to the bottom of buildings and had greater effect. “That all points to a weapon that came from a military program, used by units that understand and have training in chemical warfare operations,” Trapp says. “On balance,” he adds, a scenario involving Syrian government use of the weapons “is the more likely.”
Russia and the United States agreed over the weekend  to a plan to allow U.N. inspectors to secure Syria’s chemical weapons and destroy them by the middle of next year, a process that would be overseen by the OPCW.