The poisonus gas you are referring to is Mustard Gas and was discovered in World War 1 NOT World War 2. It was a highly deadly gas that could kill you the minute you breathed it. It blinded thousands, caused neurological damage to the nervous system and destroyed the upper respiratory system.
Poisonous Gas
HCN gas
tear gas
Chlorine, which was used as a poisonous gas in World War I.
Mustard gas was a poisonous gas used.
Mustard Gas
Chlorine gas and mustard gas were two poisonous gases commonly used during World War I. Chlorine gas caused choking and respiratory issues, while mustard gas caused severe blistering of the skin and mucous membranes. Both gases were devastating weapons that caused widespread casualties and long-lasting health effects.
New stuff? well, the idea of using poisonous gas as a weapon is new during that period
To kill the enemies
The use of poisonous gas was only banned after ww1
Poison gas was used to kill, cripple, blind, and disable enemy soldiers during the 1st World War. It was typically fired from artillery shells; but early gas projectors relied on the wind to carry the gas to its targets.
Mustard Gas Chlorine