Syrian Arab News Agency
The first report came from the government-owned Syrian Arab News Agency (SANA), which reported that "terrorists" had fired a rocket "containing chemical materials" into the Khan al-Assal area, which landed 300 meters from a Syrian army position. The news agency displayed photographs of what it said were the victims, the impact point and remains of the rocket used. Later on the day, the Syrian government wrote an official letter to the United Nations stating that opposition forces had fired a chemical rocket, "from the Kafr Da'il area towards Khan al-Asal in Aleppo governorate, some 5 km away. The missile fell in a civilian-populated area, some 300 meters from a Syrian Arab army position". The UK Channel 4 reporter Alexander Thomson reported on 23 March that an anonymous Syrian military source had briefed him that artillery reports from the Syrian Army suggested that a small home-made rocket was fired from the vicinity of Al-Bab towards a military checkpoint at the entrance of Khan al-Asal. This rocket was said to contain "a form of chlorine known as CL17, easily available as a swimming pool cleaner", in the form of "gas, dissolved in saline solution." As others pointed out, this would amount to ordinary household bleach which is prepared by dissolving chlorine in sodium hydroxide solution.