Mustard Gas…first widespread use was in WWI, which was like a Worlds Fair of new ways to fuck people up. You literally cough up chunks of your own lungs. This shit was/is so atrocious even the Nazis wouldn’t use it decades later (although that may have been more due to its unreliability than it’s horrible effects.)
Protip: anytime ammonia’s mentioned, be alert for mention of chlorine (prime ingredient of bleach.)
Probably ain’t true, but coulda been…