Why chemical weapons provoke outrage
Even coming amid Syria's bloody conflict, the 21 August attack shocked many
The Kurdish town of Halabja became a byword for the brutality of Saddam Hussein's regime
The experience of poison gas use in WWI helped form the taboo on their use
By Frank Gardne-
It has been just over three weeks since the world woke up in horror to what appears to have been a mass chemical attack on residential areas in the suburbs of Damascus on 21 August.
