Otto Hahn quotes:

First we attacked the Russian soldiers with our gases, and then when we saw the poor fellows lying there, dying slowly, we tried to make breathing easier for them by using our own life-saving devices on them.

At first the English were very surprised by our disregarding the Hague Convention. But from 1916 onward they used at least as much poison as we did.

I knew that the Hague Convention prohibited the use of poison in war. I didn't know the details of the terms of the Convention, but I did know of that prohibition.

I felt profoundly ashamed, I was very much upset.

As a result of continuous work with these highly toxic substances, our minds were so numbed that we no longer had any scruples about the whole thing. Anyway, our enemies had by now adopted our methods and as they became increasingly successful in this mode of warfare we were no longer exclusively the aggressors, but found ourselves more and more at the receiving end.