A helicopter carried out a suspected chlorine gas attack on the town of Saraqeb in Idlib province late Aug. 1, medical sources said, BBC reported Aug. 2. The helicopter dropped two barrels of the substance on the town, which is located near where a Russian military helicopter was shot down earlier in the day. A local doctor listed almost 30 confirmed cases of chlorine poisoning, which he said were mostly women and children. It is likely not the first time the town was hit with a chemical attack: Investigations found strong evidence of a previous chlorine gas attack on Saraqeb back in 2013, a charge the Syrian government denied. The Chemical Weapons Convention bans the use of weapons containing chlorine, which can cause sore eyes, irritated skin, trouble breathing and bloody foaming at the mouth. More than five years after the first shots were fired, Syria's war rages on.