WWI military training camps:

The training camps during World War I were in very poor condition. They had barely enough huts for all the men. Many of the recruits would sleep in tents because that’s all they had. The conditions during the winter were horrible and there were several cases of soldiers going on strike.

Mustard gas:
Mustard gas was the most lethal of all the poisonous chemicals used during the war. Thousands of people died from this deadly chemical agent. The gas would be put into explosives and once it was in the soil, it remained active for several weeks. The skin of victims of mustard gas blistered and their eyes became very sore and they began to vomit. Mustard gas caused internal and external bleeding and attacked the bronchial tubes, stripping off the mucous membrane. This was extremely painful and most soldiers had to be strapped to their beds. It usually took a person four or five weeks to die of mustard gas poisoning.

Comparison:
In the book, "All Quiet on the Western Front", Erich Remarque was very accurate in his description on the trenches conditions and the deadly mustard gas. He, in great detail, describes everything the young men have to do in the training camps and what life is like during war.