Chemical Weapons

As well as burning the skin, mustard gas could cause internal bleeding. It also attacked the lungs, causing a slow and agonising death

Chlorine gas dissolves in water so damp cloths helped to lessen the damage it caused. In the absence of water, men used cloths soaked in urine

Although only 7% of those affected by gas died as a direct result of their injuries, many more died years later due to the latent effects of gases and so they are not included in the figures. Many men were blinded and others suffered ill health for the rest of their lives. Cancer was also much more likely to occur in those who had been subjected to gas attacks

The Germans called mustard gas 'yellow cross' as it came in yellow marked shells. The French called it 'Yperite' after Ypres where it was first used

Tear gas did not contravene the rules of the Hague convention as it was an irritant rather than a poison

Matters were made worse when German shells hit the British gas cylinders which released their gases on the British lines

In the cold January weather the pressurised gas could not maintain itself as a vapour. This was, in fact, fortunate for the Germans as before it froze, the gas was being blown back towards them by the wind!

The poisonous gases were heavier than air and so they gathered at the bottom of trenches. Any physical exertion made the effects of the gas worse so the best thing to do was to stand still as high up in the trench as possible

Asphyxiation, due to lung damage, caused most chlorine gas deaths. The eyes were also vulnerable and many men were blinded

A British general said of poison gas, “It is a cowardly form of warfare (but) ... We cannot win this war unless we kill or incapacitate more of our enemies than they do of us, and if this can only be done by our copying the enemy in his choice of weapons, we must not refuse to do so”