Gas mask with metal container, leather, German make, 1915-1918
Poison gas was a new weapon during the First World War and was first used by the German Army in 1915. The British and French Armies soon followed suit. Fortunately, although good protective equipment was initially quite slow to develop, masks like this one eventually reduced poison gas to a major annoyance rather than the terrifying killer of the early attacks.
Among the chemical weapons used was mustard gas, which caused burns to the skin and blindness. Phosgene gas was also used and was particularly dangerous as it is colourless and almost odourless. This gas affected the lungs and breathing and could also cause heart problems.