17. Both sides used poison gas extensively during the battle
It was the French who first introduced the use of poison gas during World War I, through the use of grenades in battle in 1914. Officially the French denied their use, but not their existence. In 1915 at the battle of Ypres, the Germans used chlorine gas for the first time, and the “civilized” world, including France, howled in outrage. Soon the British and French were responding with gas attacks of their own. Chlorine, phosgene, and mustard gases were the most often used by the combatants, and their use continued throughout the war. Gas shells were used extensively at Verdun when the weather permitted.
The initial assault in February was delayed nine days because, in part, high winds restricted the efficiency of gas shells in the preliminary bombardment. When the attack did begin the French responded with diphosgene shells, and both sides used gas bombardments throughout the battle, though only on one occasion did gas significantly affect the outcome of an engagement. For the most part gas attacks at Verdun killed or significantly injured those caught unawares, but by that stage of the war, all troops were equipped with and trained in the use of their gas masks. Horses at the front to pull artillery and ammunition wagons were also equipped with masks.