Strong evidence that Syrian government used chemicals in attacks on three cities

According to doctors who treated the victims and subsequently spoke to Human Rights Watch, these attacks killed at least eleven people and resulted in symptoms consistent with exposure to chlorine in nearly 500 other people. The attacks documented by Human Rights Watch are:

• On Keferzita, a town northwest of the city of Hama in the Hama governorate, on 11 and 18 April which killed two people and affected an estimated 200 people, five of them seriously, according to a local doctor;
• On al-Teman’a, a small town north of the city of Hama in Idlib governorate on 13 and 18 April that killed at least six and affected approximately 150 people, according to a member of the medical team in the field hospital and a second witness; and
• On Telmans, a town southeast of the city of Idlib in Idlib governorate, on 21 April that killed three people and affected an estimated 133, according to a volunteer at the local field hospital.

Telmans is three kilometers east of the government-controlled military base at Wadi al-Deif and eleven kilometers from al-Hamid, areas that witnesses described as the nearest front lines.

Al-Teman’a is seven kilometers from Khan Sheikhoun, which witnesses said is the nearest front line; Keferzita is ten kilometers from Khan Sheikhoun. In an attack on Keferzita on 11 April, a witness stated that fighters from an armed non-state armed group occupied a position 500 meters outside of town.

Video evidence and information published by local activists also suggest that barrel bombs with chlorine were used in Keferzita on 12 April. Human Rights Watch says it was not able to corroborate these reports with witness accounts.

Seven of ten people interviewed by Human Rights Watch reported smelling a distinct odor in the area targeted by the barrel bombs. They remarked that this odor was familiar and similar to that of common household cleaners. The witnesses are likely referring to bleach-containing cleaners, which comprise several chlorine-containing compounds, mainly hypochlorous acid. When chlorine gas dissolves in water, including water vapor in the air and water in the mucous membranes in the nose, hypochlorous acid is formed in large amounts. The report of an odor similar to that of household cleaners is consistent with the presence of chlorine gas.

Several interviewees reported that the odor lingered for several hours. Although chlorine gas itself is not persistent, these accounts are consistent with the persistence in the environment of hypochlorite compounds formed from the chlorine gas when it mixes with vapor in the air and mucous membranes in the nose.

Half of the people interviewed by Human Rights Watch reported that the explosion of the barrel bombs produced “yellow smoke” or “dark yellowish smoke” in addition to the usual smoke from bomb explosions. A video shot on the western edge of Keferzita and uploaded to YouTube on 11 April shows the near vertical descent and detonation of an unidentified munition fully consistent with a barrel bomb dropped by helicopter. Several seconds after the explosion, a distinct yellow patch forms at the base of a large cloud of dust and debris drifting to the east. Pure chlorine is a pale yellowish green in color. Such reports of an unusual “yellow smoke” at the attack site are consistent with the release of chlorine gas from the rupture of industrial compressed gas cylinders.