Chemical and Biological Weapons
The history, science, and international law surrounding chemical and biological weapons, from World War I trenches to modern arms control challenges.
A History of Horror
Chemical weapons entered modern warfare on April 22, 1915, when German forces released 168 tons of chlorine gas at Ypres, Belgium. The gas cloud drifted across Allied trenches, causing panic and thousands of casualties. Both sides quickly escalated, deploying phosgene, mustard gas, and other agents. By the war's end, chemical weapons had caused roughly 1.3 million casualties, including 90,000 deaths. The horror of gas warfare led to the 1925 Geneva Protocol, which prohibited the use (but not production or stockpiling) of chemical and biological weapons.
Biological weapons have a longer but less extensive combat history. Japan's Unit 731 conducted grotesque biological experiments and attacks in China during World War II. During the Cold War, both the US and Soviet Union maintained massive biological weapons programs. The US unilaterally renounced its program in 1969, but the Soviet Union secretly continued its Biopreparat program, employing tens of thousands of scientists to weaponize anthrax, smallpox, and plague, a violation of the 1972 Biological Weapons Convention.