Gas mask, PH 'Tube' gas helmet, canvas with metal fittings and glass eyepieces, British, 1915

The flannel mask could be worn over a helmet and tucked into a uniform. The mask has glass eyepieces so the soldier can still see. The mask is known as the PH British anti-gas hood. PH stands for phenate hexamine, a solution used to provide protection during a phosgene or chlorine gas attack. Phosgene gas was particularly dangerous as it is colourless and almost impossible to smell. The gas affects the lungs and can cause heart problems. Symptoms appeared within 24 hours.