Entirely untrue in the Pacific theatre, with the Japanese doing human experiments both with germ and chemical agents. The largest scale use I remember was where they released infected rats (forget where) in a certain Chinese city to cause a plague.

Well and the Germans did use gas… in the camps…

Per https://en.wikipedia.org/wiki/History_of_chemical_warfare#Wo... this (a) overlooks the widespread use of chemical weapons in the Pacific theater, and (b) ascribes the non-use by Germany to humanitarian reasons, which is largely speculative. Actual quotes from officers discuss far more practical reasons: Germany feared chemical retaliation, and the horses relied upon for logistics could not be outfitted with sufficiently performant gas masks.

> Hitler had been subject to gas attacks as a foot soldier in WW1 and forbade the use of chemical weapons as inhumane.

He didn’t seem to have a problem using them against civilian targets.