The Ypres Salient - CWGC

Although the use of poison gas (declared an illegal weapon of war by the 1899 and 1907 Hague Conventions) came as a cruel surprise to the troops in the trenches, intelligence acquired by the French and British High Commands well before 22 April had pointed to the likelihood of its intended use by the Germans at Ypres. The 2nd Argyll and Sutherland Highlanders with first respirators, March-June 1915abundance and blatant nature of this information served merely to induce in the Allies the belief that such intentions were only designed to intimidate and mislead.

When used with a favourable wind, concentrations of chlorine gas (delivered as a ground level 'cloud' by cylinders installed in the parapets of front line trenches) could offer an effective tactical battlefield weapon, allowing for the occupation of enemy positions intact; though in its early days exploitation was limited by the lack of available and practical gas masks. The distress to its victims caused by the burning sensation in the eyes, nose and throat and the choking or drowning sensation that went with its inhalation helps explain the terror displayed by those who experienced at first hand this first mass gas attack and makes even more admirable the strength of character displayed by those troops who, without any specialist protective equipment, ignored its effects and remained in the fighting line.

