n. A noxious substance contained in some form of delivery system such as a shell or missile.
n. chemical substances that can be delivered using munitions and dispersal devices to cause death or severe harm to people and animals and plants
A chemical weapon (CW) is a specialized munition that uses chemicals formulated to inflict death or harm on human beings. The Organization for the Prohibition of Chemical Weapons (OPCW) states: "The term chemical weapon may also be applied to any toxic chemical 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."
They are classified as weapons of mass destruction (WMDs), though they are distinct from nuclear weapons, biological weapons, and radiological weapons. All may be used in warfare and are known by the military acronym NBC (for nuclear, biological, and chemical warfare). Weapons of mass destruction are distinct from conventional weapons, which are primarily effective due to their explosive, kinetic, or incendiary potential. Chemical weapons can be widely dispersed in gas, liquid and solid forms, and may easily afflict others than the intended targets. Nerve gas, tear gas and pepper spray are three modern examples of CW.
Lethal, unitary, chemical agents and munitions are extremely volatile and they constitute a class of hazardous chemical weapons that have been stockpiled by many nations. Unitary agents are effective on their own and do not require mixing with other agents. The most dangerous of these are nerve agents, GA, GB, GD, and VX as well as vesicant (blister) agents, which are formulations of sulfur mustard such as H, HT, and HD. They all are liquids at normal room temperature, but become gaseous when released. Widely used during the First World War, the effects of so-called mustard gas, phosgene gas and others caused lung searing, blindness, death and maiming.
, CS gas and pepper spray remain in common use for policing and riot control; while CS is considered a non-lethal weapon, pepper spray is known for its lethal potential. Under the Chemical Weapons Convention (1993), there is a legally binding, world-wide ban on the production, stockpiling, and use of chemical weapons and their precursors. Notwithstanding, large stockpiles of CW continue to exist, usually justified as a precaution against putative use by an aggressor.