Why exactly are you trying to compare mustard gas to Tor? I'm kind of lost here. But anyway, to answer your question: mustard gas is not one thing, it's a clas

Why exactly are you trying to compare mustard gas to Tor? I'm kind of lost here. But anyway, to answer your question: mustard gas is not one thing, it's a class of chemicals. But one of them became the first ever chemotherapy drugs, Mustine: https://en.m.wikipedia.org/wiki/Chlormethine https://en.m.wikipedia.org/wiki/Chlormethine