Most environmentally damaging Chemical Weapon that be used in WWI?

The only one that comes to mind for me is Lewisite, which was first synthesized before the war but not used in combat. It's like mustard gas, but somewhat more dangerous. It's not nearly as deadly as the nerve agents, but no nerve agents were developed until the 1930s and I don't think 1910s chemistry was up to the task of making nerve agents.

Although not formally a chemical weapon, PCBs cause significant environmental damage and some PCBs were known in 1914-1918. The environmental impact wasn't known then, but it is conceivable that it could have been. PCBs wouldn't be a true chemical weapon capable of killing or seriously injuring soldiers, but they could be deliberately released at the front in a scorched-earth context, to damage the ecosystems there for a very long time. Compounds of mercury or arsenic compounds such as Paris Green could also have been deliberately spread in large amounts to cause environmental damage.
 
I wouldn't underestimate rather than an individual weapon the aggregate effect of so many artillery shells (of all types) being concentrated in the Cordone Rouge, where I've seen estimates that suggest it would take 900 years to make those 60-odd square miles habitable again. That's rivaling salted nuclear weapons, but in a deeply embedded sort of way.
 
I'd say it was about it was as bad as it gets as it was. There are areas in France (Zone Rouge) that 100 years after the war they still don't allow people to enter. The soil that's been tested is about as toxic as any soil you will find on earth. What's scary is that there are projections that the soil contamination will actually get worse due to the huge number of gas shells that have not yet deteriorated enough to allow their contents to leak into the soil. The fact that there are so many shells that will continue to leak into the soil is why they estimate it will yet be centuries before the area can be truly cleaned up. The contamination here is actually worse than in Chernobyl.

Here's an article on Zone Rouge:

https://www.warhistoryonline.com/wo...years-after-wwi-it-is-still-a-no-go-area.html
 
Top