Chemical weapon

A weapon that uses toxic chemicals to kill, injure, or incapacitate people or animals through their chemical effects. It may disperse a toxic agent or use a toxic chemical itself as the weapon.

Chemical warfare agent: A toxic chemical intended for use in warfare to kill, injure, or incapacitate. This broader category distinguishes toxic agents from the weapons and delivery systems that deploy them.
World War I chemical weapons: Chemical agents used by opposing forces during the First World War. Large-scale battlefield use in 1915 made chemical warfare a defining feature of the conflict.
Halabja chemical attack: A 1988 Iraqi chemical attack on the Kurdish town of Halabja that killed thousands of civilians. The attack became a prominent example of chemical weapons used against a civilian population.
Organisation for the Prohibition of Chemical Weapons: An international organization that implements the Chemical Weapons Convention and verifies its obligations. The OPCW inspects declared facilities and investigates alleged chemical-weapon use.
Nerve agent: A class of organophosphorus chemicals that disrupt nerve signaling by inhibiting acetylcholinesterase. Nerve agents cause rapid poisoning by allowing acetylcholine to accumulate at nerve junctions.
Haber process: An industrial method for synthesizing ammonia from nitrogen and hydrogen. Industrial chemistry and wartime production made large quantities of chemical agents possible.
Tokyo subway sarin attack: A 1995 sarin attack by the Aum Shinrikyo cult on Tokyo's subway system. It demonstrated that a non-state group could conduct a chemical attack in a major city.
Chemical weapon disarmament: The elimination of chemical arsenals, production capacity, and associated weapon programs. Disarmament addresses the stockpiles and infrastructure that make renewed use possible.
Blister agent: A toxic chemical that damages skin, eyes, and airways, often causing blistering. Blister agents injure exposed tissue rather than primarily disrupting nerve signaling.
Fritz Haber: A German chemist who pioneered ammonia synthesis and organized chlorine gas warfare in World War I. Haber helped direct Germany's first large-scale chlorine attack at Ypres in 1915.

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