Probably the most feared weapon used during World War One was poison gas. A hit by an artillery shell usually resulted in an instant or quick death. A hit from a machine gun was also usually fatal but quick. Poison gas was so feared because its impact would be over time and death could be days away – possibly even more. Experienced soldiers in the trenches were attuned to gas attacks and quick to put on their respirators. They knew that diving into a shell hole during a gas attack for safety was potentially fatal as poison gas was heavier than air and would drop down into craters. In his book “All Quiet on the Western Front", Erich von Remarque wrote about a new soldier at the front who did just this during a gas attack while the experienced soldiers stayed on the ‘surface’.
H S Clapham, a British soldier on the Western Front, wrote about his experiences of a gas attack.
“At 6.0 p.m. the worst moment of the day came. The Huns started to bombard us with a shell, which was new to us. It sounded like a gigantic firecracker, with two distinct explosions. These shells came over just above the parapet, in a flood, much more quickly than we could count them. After a quarter of an hour of this sort of thing, there was a sudden crash in the trench and ten feet of the parapet, just beyond m, was blown away and everyone around blinded by dust. With my first glance I saw what looked like half a dozen bodies, mingled with sandbags, and then I smelt gas and realised that these were gas shells. I had my respirator on in a hurry and most of our men were as quick. The others were slower and suffered for it. One man was sick all over the sandbags and another was coughing his heart up. We pulled four men out of the debris unharmed. One man was unconscious, and died of gas later. Another was hopelessly smashed up and must have got it full in the chest."