A fireman from the London Fire Brigade, wearing a smoke helmet. (Photo by Topical Press Agency/Getty Images). Circa 1908

A German soldier banging on a suspended frying pan to warn of a gas attack. (Photo by General Photographic Agency/Getty Images). 1917

An American nurse wearing her gas mask while working in the trenches near the front. (Photo by Russell/Getty Images). 1918

German artillery, wearing gas masks, with a quick-firing anti-aircraft gun used mainly against low-flying aeroplanes. (Photo by General Photographic Agency/Getty Images). 1916

A soldier with a primitive gas mask brandishes a cane as a gun while on guard outside a hospital, Harrogate, Yorkshire, July 1915. (Photo by Topical Press Agency/Getty Images)

An American soldier standing guard during a German gas attack in France. (Photo by Hulton Archive/Getty Images). Circa 1918

A French soldier at the Battle of Verdun, wearing a gas mask. (Photo by Keystone/Getty Images). 1916

A German resupply team. Horses and rider are equipped with gas masks. (Photo by Hulton Archive/Getty Images). 1918

A Russian soldier advances, equipped with full breathing apparatus. (Photo by Hulton Archive/Getty Images). 1918

French soldiers loading artillery shells. They are wearing masks against gas attack. (Photo by Hulton Archive/Getty Images). August 1915

US soldiers wearing different styles of gas masks used by Allied and German forces during the First World War. (Photo by Hulton Archive/Getty Images). Circa 1917

A soldier wearing a gas mask in the trenches during WWI. (Photo by Topical Press Agency/Getty Images). August 1915

A German naval gun crew, wearing anti-flash masks, tunics and gloves designed protect against cordite burns and poisonous fumes. (Photo by Hulton Archive/Getty Images). 1916

A French officer wearing a new anti-gas mask. (Photo by Hulton Archive/Getty Images). 17th August 1916

Austrian soldiers in the trenches demonstrating their gas masks. (Photo by Hulton Archive/Getty Images). June 1916

Russian officers release gas during gas attack training at Newmarket. (Photo by Topical Press Agency/Getty Images). October 1910

German artillery men wearing gas masks as they operate a heavy gun. (Photo by Hulton Archive/Getty Images). Circa 1915

French troops wearing an early form of gas mask in the trenches during the 2nd Battle of Ypres. (Photo by Hulton Archive/Getty Images). Circa 1915

An American soldier dressed for a gas attack during World War I, circa 1916. (Photo by Hulton Archive/Getty Images)

People pass the time playing cards, whilst in a wine cellar sheltering from a Gotha bombing raid. (Photo by Hulton Archive/Getty Images). 1st February 1918

German naval crew wearing breathing apparatus to be worn during gas attacks. (Photo by Hulton Archive/Getty Images). Circa 1911

Gas masked mine rescue workers at Wheatley near Doncaster in Yorkshire, practise artificial respiration and resuscitation techniques for an asphyxiated colleague. (Photo by Fox Photos/Getty Images). 1925

A very simple 'gas' mask used during WWI by the allies in the campaign in France. (Photo by Hulton Archive/Getty Images). Circa 1915