Chemical weapon

A chemical weapon (CW) is a specialized munition that uses chemicals formulated to inflict death or harm on humans. According to the Organisation for the Prohibition of Chemical Weapons (OPCW), this can be any chemical compound intended as a weapon "or its precursor that can cause death, injury, temporary incapacitation or sensory irritation through its chemical action. Munitions or other delivery devices designed to deliver chemical weapons, whether filled or unfilled, are also considered weapons themselves." Lethal chemical weapons include nerve agents (tabun, sarin, soman, VX/VR, and Novichok) and blister agents (primarily mustard gas). Non-lethal chemical weapons include tear gases like CS gas and pepper spray and incapacitating agents like 3-Q/BZ. Chemical weapons are typically highly volatile, while some like VX are persistent. They may be unitary or binary, combining from precursors in situ. Toxin weapons, as complex biologically produced chemicals, blur the line with biological weapons. Lethal chemical weapons are considered weapons of mass destruction, alongside biological weapons, radiological weapons, and nuclear weapons. Under the OPCW definition, toxic agents are not chemical weapons when used for another of their properties e.g. the herbicide Agent Orange or the incendiary white phosphorus. The history of chemical warfare dates from antiquity. Chemical weapons were first used on a large scale by most major powers in World War I, employing mustard gas, the choking agents phosgene gas and chlorine, and others, causing lung scarring, blindness, and death. During World War II, Nazi Germany used a commercial hydrogen cyanide blood agent trade-named Zyklon B to commit industrialised genocide against Jews and other populations in gas chambers. The Holocaust resulted in the largest death toll to chemical weapons in history. The Empire of Japan also used chemical warfare in China during the Second Sino-Japanese War, including mustard gas and lewisite. Nazi Germany discovered nerve agents...