Bruising and Bleeding. Bruising or bleeding after an injury is normal. However, some people have disorders that cause them to bruise or bleed too easily. Sometimes people bleed without any obvious triggering event or injury.
The skin of victims of mustard gas blistered, the 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.
The History of the 51st (Highland) Division 1914-1918 Frederick William Bewsher. The gas used by the enemy is generally a mixture of chlorine and phosgene, both of which are strongly asphyxiating. Military Instructors Manual James P. Cole and Oliver Schoonmaker. England received 900 tons of our chlorpicrin and 368 tons of American phosgene.