Where can I learn more about this more persistant mustard gas? As far as I've been able to find out from online sources there doesn't seem to be a difference between WW1 and WW2 versions, but I'd like to know more.
So, hypothetically if the Germans mustard gas Leningrad, Moscow, and Stalingrad, plus bomb Soviet oil facilities at Baku and other caucasian sources, how long could the Soviets continued to fight?
Depends on how they respond to the first round of attacks. With Soviet industry already moved east of the Urals their productive capacity won't be hurt much by the assault, the real question is will Stalin rush to save the population from the encroaching German onslaught? Either way scorched earth will definitely be the phrase of the day in the USSR.