Chemical weapons have been used since the Stone Age. Sounds crazy, eh? Then, the weapons werein the form of poisoned arrows. These poisons were derived mainly from scorpion or snake venom, and possibly poisonous plants.
Gas warfare can also be traced back to the Spartans. The Mongols used poisonous gas in the 13th century.
Chemical warfare is not a 20th century invention. It merely escalated in usage, and more importantly, amount of causalities The Nazis did it, though they weren’t very successful. Germany also used the deadly Mustard Gas in the first World War.
But during the Cold War, both Soviet and Western governments put enormous resources into the development of chemical and biological weapons. This time period was this tipping point for chemical weapons. They were used on a wide scale, and the world eventually paid attention. The capabilities of these weapons affected many millions during this conflict, and it marked a time when the world would be forced to address the problem.
The problem is, we focus on the deadly chemicals. You know, the ones that kill you. What we miss is, the ones that make you stronger.