The German army used chlorine as a poison gas for the first time against Allied troops at the Second Battle of Ypres on 22 April 1915.[1] As an immediate response, the British began issuing cotton wool wrapped in muslin to its troops by 3 May.Шаблон:Sfn This was followed by the Black Veil Respirator, invented by John Scott Haldane. The Black Veil was a cotton pad soaked in an absorbent solution which was secured over the mouth using black cotton veiling.Шаблон:Sfn The mask was treated in a solution of sodium hyposulphate, sodium carbonate, glycerine and water.Шаблон:Sfn The solution retained sufficient moisture so that it was unnecessary to dip the mask in a solution prior to use, so long as it was stored in its purpose-built waterproof satchel. The veiling could be drawn up to cover the eyes, providing some protection against lachrymatory agents; however, the mask itself still only provided limited protection against chlorine gas.Шаблон:Sfn
First issued on 20 May 1915, the Black Veil had a pouch for the pad to sit in and a string to hold the mask in to the face, and was thus an improvement to the hand-held cloth. However, it was of fragile construction, required training to use effectively, and largely immobilized its wearers because they were concerned about the mask coming loose.Шаблон:Sfn The Black Veil Respirator was soon replaced by the British Smoke Hood, an over the head canvas hood treated with chlorine-absorbing chemicals, invented by Cluny MacPherson.[2][3] Following the introduction of the British Smoke Hood, the Black Veil was relegated to an emergency backup.
