After the German chemist Fritz Haber carried out the first attack using chlorine gas in April 1915, reach into gasses that could be used on the battlefield continued at the Kaiser Wilhelm Institut in Berlin.
In the autumn of 1916 two chemists, Wilhelm Lommel and Wilhelm Steinkopf, developed a gas that they named LOST, which was a combination of the first two letters of one of their surnames and the last two letters of the other.
LOST was in fact not a gas, but rather a liquid that vaporises at temperature of 217C°.
Due to it yellow-brown colour that resembles that of a mustard plant, it was soon given the name mustard gas.
By 1917 grenades had already been used in gas attacks for some time, as they were able to neutralise the enemy more efficiently and more quickly than discharging clouds of gas from large cylinders when the wind was blowing in the right direction.
Grenades containing mustard gas were colour coded by the Germans with a yellow cross. This earned it the nick-name “Gelbkreuz”. As it was first used in battle, near to the West Flemish town of Ieper it is also known as Yperite.
A few days before the first mustard gas attack, the Germans used another new gas Blaukreuz that contained arsenic, chlorine and a dose of mustard gas on the battlefield near to Nieuwpoort.
Blaukreuz caused heavy sneezing and coughing fits making it impossible for the soldiers to keep their gas-masks on.
As soon as they had taken after their gas masks they fell victim to the pphosgene (also known as Grünkreuz) grenades that were fired soon after the Blaukreuz grenades had been launched.