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.Longerich, Peter (2010). Holocaust: The Nazi Persecution and Murder of the Jews. Oxford; New York: Oxford University Press. . The Holocaust resulted in the largest death toll to chemical weapons in history.From Cooperation to Complicity: Degussa in the Third Reich, Peter Hayes, 2004, pp 2, 272, 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 during the war, but did not use them for fear of Allied retaliation. In the Cold War, many countries stockpiled chemical weapons. The Soviet and United States chemical weapons programs became the first and second largest in world history, focusing on sarin, VX/VR, and mustard, primarily for battlefield use in Europe. Chemical weapons were repeatedly used in the Iran–Iraq War and Syrian civil war.
At the end of the Cold War, the 1993 Chemical Weapons Convention sought a legally binding, worldwide ban on the production, stockpiling, and use of chemical weapons and their precursors. Large-scale stockpile destruction efforts followed, with the US eliminating its arsenal by 2023. the treaty has 193 state parties; Syria and Russia are widely believed to have violated its prohibitions on stockpiling and use while Israel and North Korea remain non-parties. Small research quantities are treaty-permitted as part of CBRN defense.
Use
Chemical warfare involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare and biological warfare, which together make up NBC, the military initialism for Nuclear, Biological, and Chemical (warfare or weapons). None of these fall under the term conventional weapons, which are primarily effective because of their destructive potential. Chemical warfare does not depend upon explosive force to achieve an objective. It depends upon the unique properties of the chemical agent weaponized.
A lethal agent is designed to injure, incapacitate, or kill an opposing force, or deny unhindered use of a particular area of terrain. Defoliants are used to quickly kill vegetation and deny its use for cover and concealment. Chemical warfare can also be used against agriculture and livestock to promote hunger and starvation. Chemical payloads can be delivered by remote controlled container release, aircraft, or rocket. Protection against chemical weapons includes proper equipment, training, and decontamination measures.
Manner and form
There are three basic configurations in which these agents are stored. The first are self-contained munitions like projectiles, cartridges, mines, and rockets; these can contain propellant or explosive components. The next form are aircraft-delivered munitions. Together they constitute the two forms that have been weaponized and are ready for their intended use. The U.S. stockpile consisted of 39% of these weapon ready munitions. The final of the three forms is raw agent housed in bulk containers. The remaining 61% of the US stockpile was stored in this manner. Whereas these chemicals exist in liquid form at normal room temperature, the sulfur mustards H and HD freeze in temperatures below . Mixing lewisite with distilled mustard lowers the freezing point to .
Higher temperatures are a bigger concern because the possibility of an explosion increases as the temperatures rise. A fire at one of these facilities would endanger the surrounding community as well as the personnel at the installations. Perhaps more so for the community having much less access to protective equipment and specialized training. The Oak Ridge National Laboratory conducted a study to assess capabilities and costs for protecting civilian populations during related emergencies, and the effectiveness of expedient, in-place shelters. Unitary versus binary weapons
Binary munitions contain two, unmixed and isolated chemicals that do not react to produce lethal effects until mixed. This usually happens just prior to battlefield use. In contrast, unitary weapons are lethal chemical munitions that produce a toxic result in their existing state. The majority of the chemical weapon stockpile is unitary and most of it is stored in one-ton bulk containers.
Lethality
Chemical weapons are said to "make deliberate use of the toxic properties of chemical substances to inflict death". At the start of World War II it was widely reported in newspapers that "entire regions of Europe" would be turned into "lifeless wastelands". However, chemical weapons were not used to the extent predicted by the press.
An unintended chemical weapon release occurred at the port of Bari. A German attack on the evening of December 2, 1943, damaged U.S. vessels in the harbour and the resultant release from their hulls of mustard gas inflicted a total of 628 casualties.
The U.S. Government was highly criticized for exposing American service members to chemical agents while testing the effects of exposure. These tests were often performed without the consent or prior knowledge of the soldiers affected. Australian service personnel were also exposed as a result of the "Brook Island trials" carried out by the British Government to determine the likely consequences of chemical warfare in tropical conditions; little was known of such possibilities at that time.
Some chemical agents are designed to produce mind-altering changes, rendering the victim unable to perform their assigned mission. These are classified as incapacitating agents, and lethality is not a factor of their effectiveness.
History
Simple chemical weapons were used sporadically throughout antiquity and into the Industrial age.Samir S. Patel, "Early Chemical Warfare – Dura-Europos, Syria," Archaeology, Vol. 63, No. 1, January/February 2010, (accessed October 3, 2014) It was not until the 19th century that the modern conception of chemical warfare emerged, as various scientists and nations proposed the use of asphyxiating or poisonous gases. So alarmed were nations that multiple international treaties, discussed below, were passed banning chemical weapons. This however did not prevent the extensive use of chemical weapons in World War I. The development of chlorine gas, among others, was used by both sides to try to break the stalemate of trench warfare. Though largely ineffective over the long run, it decidedly changed the nature of the war. In most cases the gases used did not kill, but instead horribly maimed, injured, or disfigured casualties. Estimates for military gas casualties range from 500k to 1.3 million, with a few thousand additional civilian casualties as collateral damage or production accidents.
The interwar period saw occasional use of chemical weapons, mainly by multiple European colonial forces to put down rebellions. The Italians also used poison gas during their 1936 invasion of Ethiopia."Chemical Weapons" in Historical Dictionary of Ethiopia, 2d ed. (eds. David H. Shinn & Thomas P. Ofcansky: Scarecrow Press, 2013). In Nazi Germany, much research went into developing new chemical weapons, such as potent nerve agents.Corum, James S., The Roots of Blitzkrieg, University Press of Kansas, USA, 1992, pp.106-107. However, chemical weapons saw little battlefield use in World War II. Both sides were prepared to use such weapons, but the Allied powers never did, and the Axis used them only very sparingly. The reason for the lack of use by the Nazis, despite the considerable efforts that had gone into developing new varieties, might have been a lack of technical ability or fears that the Allies would retaliate with their own chemical weapons. Those fears were not unfounded: the Allies made comprehensive plans for defensive and retaliatory use of chemical weapons, and stockpiled large quantities.Paxman and Harris: Churchill's plans 'to drench Germany with poison gas' and anthrax - Robert Harris and Jeremy Paxman, p132-35.Callum Borchers, Sean Spicer takes his questionable claims to a new level in Hitler-Assad comparison, The Washington Post (April 11, 2017). Japanese forces used them more widely, though only against their Asian enemies, as they also feared that using it on Western powers would result in retaliation. Chemical weapons were frequently used against Kuomintang and Chinese communist troops.Yuki Tanaka, Poison Gas, the Story Japan Would Like to Forget, Bulletin of the Atomic Scientists, October 1988, p. 16-17 However, the Nazis did extensively use poison gas against civilians in the Holocaust. Vast quantities of Zyklon B gas and carbon monoxide were used in the gas chambers of Nazi extermination camps, resulting in the overwhelming majority of some three million deaths. This remains the deadliest use of poison gas in history.Patrick Coffey, American Arsenal: A Century of Weapon Technology and Strategy (Oxford University Press, 2014), p. 152-54.James J. Wirtz, "Weapons of Mass Destruction" in Contemporary Security Studies (4th ed.), ed. Alan Collins, Contemporary Security Studies (Oxford University Press, 2016), p. 302.
The post-war era has seen limited, though devastating, use of chemical weapons. Some 100,000 Iranian troops were casualties of Iraqi chemical weapons during the Iran–Iraq War. Iraq used mustard gas and nerve agents against its own civilians in the 1988 Halabja chemical attack.On this day: 1988: Thousands die in Halabja gas attack, BBC News (March 16, 1988). The Cuban intervention in Angola saw limited use of organophosphates. The Syrian government has used sarin, chlorine, and mustard gas in the Syrian civil war generally against civilians.Syria Used Chlorine in Bombs Against Civilians, Report Says, The New York Times, Rick Gladstone, August 24, 2016 retrieved August 25, 2016. Terrorist groups have also used chemical weapons, notably in the Tokyo subway sarin attack and the Matsumoto incident.Seto, Yasuo. "The Sarin Gas Attack in Japan and the Related Forensic Investigation." The Sarin Gas Attack in Japan and the Related Forensic Investigation. Organisation for the Prohibition of Chemical Weapons, June 1, 2001. Web. February 24, 2017.