Gas mask usage dates back to ancient Greece. They used sponges. Since then, various techniques and technologies have been used as inhalation filtration systems.
The first use of poison gas on the Western Front was by the Germans at Ypres on April 22, 1915. The initial response was to give the troops cotton mouth pads to protect their breathing. The primitive masks went through several stages of development before being superseded by the canister gas mask in 1916. The mask is connected to the tin which contains absorbent materials.
By 1944 the US Army Chemical Warfare Service developed a mask made of plastic and rubber which greatly reduced the weight and size of the masks.
Most civilians learned how to use gas masks through the civil defense department, but children received most gas mask education in school drills. Schools enforced the compulsory carrying of gas masks at all times.