Always scope for more, but as a starting point there are some useful answers in [the Chemical Weapons section of the FAQ] (https://www.reddit.com/r/AskHistorians/wiki/faq/militaryhistory/wwii/therest#wiki_chemical_weapons), particularly /u/kojin on [Why didn't Germany use chemical weapons during WW2?] (https://www.reddit.com/r/AskHistorians/comments/42nqi1/why_didnt_germany_use_chemical_weapons_during_ww2/czcf61i/)