Chemical weapon

  (Redirected from Chemical weapons)

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), "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."[2]

Chemical weapon
Pallets of 155 mm artillery shells containing "HD" (mustard gas) at Pueblo Depot Activity (PUDA) chemical weapons storage facility
Blister agents
Phosgene oxime(CX)
Mustard gas (Yperite)(HD)
Nitrogen mustard(HN)
Nerve agents
Blood agents
Cyanogen chloride(CK)
Hydrogen cyanide(AC)
Choking agents
Soviet chemical weapons canisters from a stockpile in Albania.jpg
Soviet chemical weapons canister from an Albanian stockpile[1]

Chemical weapons are classified as weapons of mass destruction (WMD), 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 chemical weapons.

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) and vesicant (blister) agents, which include 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 World War I, the effects of so-called mustard gas, phosgene gas and others caused lung searing, blindness, death and maiming.

The Nazi Germans during World War II committed genocide (mainly against Jews but including other targeted populations) using a commercial hydrogen cyanide blood agent trade-named Zyklon B. Discharging it in large gas chambers was the preferred method to efficiently murder their victims in a continuing industrial fashion.[3] The Holocaust resulted in the largest death toll to chemical weapons in history.[4]

As of 2016, 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, worldwide ban on the production, stockpiling, and use of chemical weapons and their precursors. Notwithstanding, large stockpiles of chemical weapons continue to exist, usually justified as a precaution against putative use by an aggressor.


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 British gas bomb that was used during World War I.

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.


John Singer Sargent's iconic World War I painting: Gassed, showing blind casualties on a battlefield after a mustard gas attack

Simple chemical weapons were used sporadically throughout antiquity and into the Industrial age.[5] 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 gasses.[6] 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 many cases the gasses used did not kill, but instead horribly maimed, injured, or disfigured casualties. Some 1.3 million gas casualties were recorded, which may have included up to 260,000 civilian casualties.[7][8][9]

The interwar years saw occasional use of chemical weapons, mainly to put down rebellions.[10] In Nazi Germany, much research went into developing new chemical weapons, such as potent nerve agents.[11] 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.[12][13] 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.[14] 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.[15][16][17][18]

The post-war era has seen limited, though devastating, use of chemical weapons. The U.S. program, codenamed Operation Ranch Hand, sprayed more than 20 million gallons of various herbicides over Vietnam, Cambodia and Laos from 1961 to 1971. Agent Orange, which contained the deadly chemical dioxin, was the most commonly used herbicide. Some 400.000 people were killed or maimed as a result of herbicides like Agent Orange. Some 100,000 Iranian troops were casualties of Iraqi chemical weapons during the Iran–Iraq War.[19][20][21] Iraq used mustard gas and nerve agents against its own civilians in the 1988 Halabja chemical attack.[22] The Cuban intervention in Angola saw limited use of organophosphates.[23] The Syrian government has used sarin, chlorine, and mustard gas in the Syrian civil war – generally against civilians.[24][25] Terrorist groups have also used chemical weapons, notably in the Tokyo subway sarin attack and the Matsumoto incident.[26][27] See also chemical terrorism.

International lawEdit

Before the Second World WarEdit

International law has prohibited the use of chemical weapons since 1899, under the Hague Convention: Article 23 of the Regulations Respecting the Laws and Customs of War on Land adopted by the First Hague Conference "especially" prohibited employing "poison and poisoned arms".[28][29] A separate declaration stated that in any war between signatory powers, the parties would abstain from using projectiles "the object of which is the diffusion of asphyxiating or deleterious gases".[30]

The Washington Naval Treaty, signed February 6, 1922, also known as the Five-Power Treaty, aimed at banning chemical warfare but did not succeed because France rejected it. The subsequent failure to include chemical warfare has contributed to the resultant increase in stockpiles.[31]

The Geneva Protocol, officially known as the Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or other Gases, and of Bacteriological Methods of Warfare, is an International treaty prohibiting the use of chemical and biological weapons. It was signed at Geneva June 17, 1925, and entered into force on February 8, 1928. 133 nations are listed as state parties[32] to the treaty. Ukraine is the newest signatory; acceding August 7, 2003.[33]

This treaty states that chemical and biological weapons are "justly condemned by the general opinion of the civilised world". And while the treaty prohibits the use of chemical and biological weapons, it does not address the production, storage, or transfer of these weapons. Treaties that followed the Geneva Protocol did address those omissions and have been enacted.

Modern agreementsEdit

The 1993 Chemical Weapons Convention (CWC) is the most recent arms control agreement with the force of International law. Its full name is the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction. That agreement outlaws the production, stockpiling and use of chemical weapons. It is administered by the Organisation for the Prohibition of Chemical Weapons (OPCW), which is an independent organization based in The Hague.[34]

The OPCW administers the terms of the CWC to 192 signatories, which represents 98% of the global population. As of June 2016, 66,368 of 72,525 metric tonnes, (92% of chemical weapon stockpiles), have been verified as destroyed.[35][36] The OPCW has conducted 6,327 inspections at 235 chemical weapon-related sites and 2,255 industrial sites. These inspections have affected the sovereign territory of 86 States Parties since April 1997. Worldwide, 4,732 industrial facilities are subject to inspection under provisions of the CWC.[36]

Countries with stockpilesEdit

Manner and formEdit

Johnston Atoll Chemical Agent Disposal System prior to demolition.
A Swedish Army soldier wearing a chemical agent protective suit (C-vätskeskydd) and protection mask (skyddsmask 90).

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 and/or explosive components. The next form are aircraft-delivered munitions. This form never has an explosive component.[37] Together they comprise 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 are raw agent housed in one-ton containers. The remaining 61%[37] of the stockpile was in this form.[38] Whereas these chemicals exist in liquid form at normal room temperature,[37][39] the sulfur mustards H, and HD freeze in temperatures below 55 °F (12.8 °C). Mixing lewisite with distilled mustard lowers the freezing point to −13 °F (−25.0 °C).[40]

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.[41] Perhaps more so for the community having much less access to protective equipment and specialized training.[42] The Oak Ridge National Laboratory conducted a study to assess capabilities and costs for protecting civilian populations during related emergencies,[43] and the effectiveness of expedient, in-place shelters.[44]


Stockpile/disposal site locations for the United States' chemical weapons and the sites operating status as of August 28, 2008.

United StatesEdit

The stockpiles, which have been maintained for more than 50 years,[31] are now considered obsolete.[45] Public Law 99-145, contains section 1412, which directs the Department of Defense (DOD) to dispose of the stockpiles. This directive fell upon the DOD with joint cooperation from the Federal Emergency Management Agency (FEMA).[37] The Congressional directive has resulted in the present Chemical Stockpile Disposal Program.

Historically, chemical munitions have been disposed of by land burial, open burning, and ocean dumping (referred to as Operation CHASE).[46] However, in 1969, the National Research Council (NRC) recommended that ocean dumping be discontinued. The Army then began a study of disposal technologies, including the assessment of incineration as well as chemical neutralization methods. In 1982, that study culminated in the selection of incineration technology, which is now incorporated into what is known as the baseline system. Construction of the Johnston Atoll Chemical Agent Disposal System (JACADS) began in 1985.

This was to be a full-scale prototype facility using the baseline system. The prototype was a success but there were still many concerns about CONUS operations. To address growing public concern over incineration, Congress, in 1992, directed the Army to evaluate alternative disposal approaches that might be "significantly safer", more cost effective, and which could be completed within the established time frame. The Army was directed to report to Congress on potential alternative technologies by the end of 1993, and to include in that report: "any recommendations that the National Academy of Sciences makes ..."[38] In June 2007, the disposal program achieved the milestone of reaching 45% destruction of the chemical weapon stockpile.[47] The Chemical Materials Agency (CMA) releases regular updates to the public regarding the status of the disposal program.[48] By October 2010, the program had reached 80% destruction status.[49]


Chemical weapons are said to "make deliberate use of the toxic properties of chemical substances to inflict death".[50] At the start of World War II it was widely reported in newspapers that "entire regions of Europe" would be turned into "lifeless wastelands".[51] 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.[52][53][54]

An Australian observer who has moved into a gas-affected target area to record results, examines an un-exploded shell.

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.[55] Australian service personnel were also exposed as a result of the "Brook Island trials"[56] 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.[57]

Exposure during Operation Iraqi Freedom and Operation New DawnEdit

During Operation Iraqi Freedom and Operation New Dawn, service members who demolished or handled older explosive ordnance may have been exposed to blister agents (mustard agent) or nerve agents (sarin).[58] According to The New York Times, "In all, American troops secretly reported finding roughly 5,000 chemical warheads, shells or aviation bombs, according to interviews with dozens of participants, Iraqi and American officials, and heavily redacted intelligence documents obtained under the Freedom of Information Act."[59] Among these, over 2,400 nerve-agent rockets were found in summer 2006 at Camp Taji, a former Republican Guard compound. "These weapons were not part of an active arsenal"; "they were remnants from an Iraqi program in the 1980s during the Iran-Iraq war".[59]

Unitary versus binary weaponsEdit

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.[60] The majority of the chemical weapon stockpile is unitary and most of it is stored in one-ton bulk containers.[61][62]

See alsoEdit


  1. ^ "Types of Chemical Weapons" (PDF). Federation of American Scientists. Archived from the original (PDF) on March 3, 2016. Retrieved June 27, 2016.
  2. ^ "Brief Description of Chemical Weapons". Organisation for the Prohibition of Chemical Weapons. Organisation for the Prohibition of Chemical Weapons. Retrieved October 21, 2014.
  3. ^ Longerich, Peter (2010). Holocaust: The Nazi Persecution and Murder of the Jews. Oxford; New York: Oxford University Press. ISBN 978-0-19-280436-5.
  4. ^ From Cooperation to Complicity: Degussa in the Third Reich, Peter Hayes, 2004, pp 2, 272, ISBN 0-521-78227-9
  5. ^ Samir S. Patel, “Early Chemical Warfare – Dura-Europos, Syria,” Archaeology, Vol. 63, No. 1, January/February 2010, (accessed October 3, 2014)
  6. ^ Eric Croddy (2002). Chemical and Biological Warfare: A Comprehensive Survey for the Concerned Citizen. Springer. p. 131. ISBN 9780387950761.
  7. ^ D. Hank Ellison (August 24, 2007). Handbook of Chemical and Biological Warfare Agents, Second Edition. CRC Press. pp. 567–570. ISBN 978-0-8493-1434-6.
  8. ^ Max Boot (August 16, 2007). War Made New: Weapons, Warriors, and the Making of the Modern World. Gotham. pp. 245–250. ISBN 978-1-5924-0315-8.
  9. ^ Gross, Daniel A. (Spring 2015). "Chemical Warfare: From the European Battlefield to the American Laboratory". Distillations. 1 (1): 16–23. Retrieved March 20, 2018.
  10. ^ "Chemical Weapons" in Historical Dictionary of Ethiopia, 2d ed. (eds. David H. Shinn & Thomas P. Ofcansky: Scarecrow Press, 2013).
  11. ^ Corum, James S., The Roots of Blitzkrieg, University Press of Kansas, USA, 1992, pp.106-107.
  12. ^ "Paxman and Harris", p132-35.
  13. ^ Callum Borchers, Sean Spicer takes his questionable claims to a new level in Hitler-Assad comparison, The Washington Post (April 11, 2017).
  14. ^ Yuki Tanaka, Poison Gas, the Story Japan Would Like to Forget, Bulletin of the Atomic Scientists, October 1988, p. 16-17
  15. ^ "Nazi Camps". Holocaust Encyclopedia. United States Holocaust Memorial Museum. Retrieved April 19, 2020.
  16. ^ Schwartz, Terese Pencak. "The Holocaust: Non-Jewish Victims". Jewish Virtual Library. Retrieved April 19, 2020.
  17. ^ Patrick Coffey, American Arsenal: A Century of Weapon Technology and Strategy (Oxford University Press, 2014), p. 152-54.
  18. ^ 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.
  19. ^ Fassihi, Farnaz (October 27, 2002), "In Iran, grim reminders of Saddam's arsenal", New Jersey Star Ledger
  20. ^ Paul Hughes (January 21, 2003), "It's like a knife stabbing into me", The Star (South Africa)
  21. ^ Sciolino, Elaine (February 13, 2003), "Iraq Chemical Arms Condemned, but West Once Looked the Other Way", The New York Times, archived from the original on May 27, 2013
  22. ^ On this day: 1988: Thousands die in Halabja gas attack, BBC News (March 16, 1988).
  23. ^ Tokarev, Andrei; Shubin, Gennady, eds. (2011). Bush War: The Road to Cuito Cuanavale: Soviet Soldiers' Accounts of the Angolan War. Auckland Park: Jacana Media (Pty) Ltd. pp. 128–130. ISBN 978-1-4314-0185-7.
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  25. ^ Syria Used Chlorine in Bombs Against Civilians, Report Says, The New York Times, Rick Gladstone, August 24, 2016 retrieved August 25, 2016.
  26. ^ "Japan executes sarin gas attack cult leader Shoko Asahara and six members". The Guardian. Archived from the original on June 22, 2019. Retrieved July 18, 2019.
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  28. ^ Article 23. Retrieved June 27, 2016.
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  33. ^ "High Contracting Parties to the Geneva Protocol". Archived from the original on September 6, 2013. Retrieved September 14, 2013.
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  36. ^ a b "Organisation for the Prohibition of Chemical Weapons (home page)". Retrieved June 27, 2016.
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  39. ^ "Record Version Written Statement by Carmen J. Spencer Deputy Assistant Secretary of the Army" (PDF). June 15, 2010. Archived from the original (PDF) on November 11, 2013. Retrieved November 11, 2013.
  40. ^ "FM 3–9 (field manual)" (PDF). Retrieved August 10, 2010.
  41. ^ Rogers, G. O.; Watson, A. P.; Sorensen, J. H.; Sharp, R. D.; Carnes, S. A. (April 1, 1990). "Evauluating Protective Actions for Chemical Agent Emergencies" (PDF). Archived from the original (PDF) on November 11, 2013. Retrieved November 11, 2013.
  42. ^ "Methods for Assessing and Reducing Injury from Chemical Accidents" (PDF). John Wiley & Sons Ltd. Cite journal requires |journal= (help)
  43. ^ "Technical Options for Protecting Civilians from Toxic Vapors and Gases" (PDF). Oak Ridge National Laboratory. Archived from the original (PDF) on January 13, 2010. Retrieved August 11, 2010. Cite journal requires |journal= (help)
  44. ^ "Effectiveness of expedient sheltering in place in a residents" (PDF). Journal of Hazardous Materials, Archived from the original (PDF) on November 11, 2013. Retrieved November 11, 2013.
  45. ^ John Pike. "Chemical Weapons". Retrieved November 11, 2013.
  46. ^ John Pike. "Operation CHASE (for "Cut Holes and Sink 'Em")". Retrieved August 9, 2010.
  47. ^ "45 Percent CWC Milestone". U.S. Army Chemical Materials Agency. Archived from the original on June 8, 2011. Retrieved August 9, 2010. Cite journal requires |journal= (help)
  48. ^ "Agent Destruction Status". United States Army Chemical Materials Agency. Archived from the original on June 24, 2010. Retrieved June 16, 2010. Cite journal requires |journal= (help)
  49. ^ "CMA Reaches 80% Chemical Weapons Destruction Mark". Archived from the original on November 23, 2010. Retrieved November 7, 2010.
  50. ^ "" (PDF). Archived from the original (PDF) on July 3, 2007. Retrieved August 9, 2010.
  51. ^ "[2.0] A History of Chemical Warfare (2)". Retrieved August 9, 2010.
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  55. ^ "Is Military Research Hazardous to Veterans' Health? Lessons Spanning Half a Century. United States Senate December 8, 1994". Archived from the original on August 13, 2006. Retrieved August 9, 2010.
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  57. ^ "007 Incapacitating Agents". Archived from the original on June 16, 2010. Retrieved August 9, 2010.
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  59. ^ a b C. J. Chivers. The Secret Casualties of Iraq's Abandoned Chemical Weapons. The New York Times. October 14, 2014.
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  62. ^ Institute of Medicine; Committee on the Survey of the Health Effects of Mustard Gas and Lewisite (1993). Veterans at Risk: The Health Effects of Mustard Gas and Lewisite. National Academies Press. p. 49. ISBN 978-0-309-04832-3.

Further readingEdit

  • Glenn Cross, Dirty War: Rhodesia and Chemical Biological Warfare, 1975–1980, Helion & Company, 2017

External linksEdit