[RaceBannon]

I might be wrong on the amounts, but not the intended point: While Soldiers died by the hundreds by gassing, they were concentrated in one area, they were attacked by hundreds of shells, and had a climate condition that was favorable to the weapon dispersal.

A City is not. It would take about 300 to 400 Pounds of Hydrogen cyanide to poisona building and kill everyone inside it, (Skyscraper like WTC or similar) just using a charcoal briquette bag wont do it. (But that would kill over a hundred!)

[Poohbah]

The French used hydrogen cyanide because it was unquestionably lethal.

Unfortunately, HCN is so light that it just floats from the dispersal point, instead of staying low and getting into people's lungs.