In accordance with The Geneva Protocol of 1925, Nazi Germany refrained from the tactical use of chemical and biological weapons in war, possibly due to the personal experiences of Adolf Hitler as a sergeant in the Kaiser's army where he was gassed by British troops in 1918.
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One reported incident indicates the German army eventually used poison gas on survivors of the Battle of Kerch on the Eastern Crimean peninsula. The gas warfare was conducted by the Wehrmacht's Chemical Forces and organized by a special detail of SS troops with the help of a field engineer battalion. Chemical Forces General Ochsner reported to German command in June 1942 that a chemical unit had taken part in the battle. After the battle in mid-May 1942, roughly 3,000 Red Army soldiers and Soviet civilians not evacuated by sea were besieged in a series of caves and tunnels in the nearby Adzhimuskai quarry. After holding out for approximately three months, "poison gas was released into the tunnels, killing all but a few score of the Soviet defenders." Thousands of those killed around Adzhimushk were documented to have been killed by asphyxiation from gas.
In February 1943, German troops stationed in Kuban received a telegram.
...Russians should be eventually cleared out of the mountain range with gas.
The troops also received two wagons of toxin antidotes.