Chemical weapons in World War I in Palestine during the Second Battle of Gaza. Russia began manufacturing chlorine gas in 1916, with phosgene being produced later in the year. Most of the manufactured gas was never used. The British Army first used mustard gas in November 1917 at Cambrai, after their armies had captured a stockpile of German mustard gas shells. It took the British more than a year to develop their own mustard gas weapon, with production of the chemicals centred on Avonmouth Docks. (The only option available to the British was the Despretz–Niemann–Guthrie process). This was used first in September 1918 during the breaking
Action of 22 October 1917 Action of 22 October 1917 The Action of 22 October 1917 was an attack during the Third Battle of Ypres in the First World War by the British Fifth Army and the French First Army against the German 4th Army. British attacks had been repulsed at Passchendaele by the 4th Army at the Battle of Poelcappelle (9 October) and the First Battle of Passchendaele (12 October). While the British waited for another dry spell and the completion of plank roads up to the new front line, the Canadian Corps and fresh British divisions were transferred to Flanders by the British