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Last Updated: June, 2015

Iran is one of the few countries in the world that has encountered chemical warfare (CW) on the battlefield since 1918.

Iranian troops and civilians suffered tens of thousands of casualties from Iraqi chemical weapons during the Iran-Iraq War of 1980 to 1988. As a result, Iran has strongly opposed the use and possession of chemical weapons. Iran ratified the Chemical Weapons Convention (CWC) in 1997. Nevertheless, several Western governments have accused Iran of developing and maintaining its own arsenal of chemical weapons. Although U.S. intelligence agencies between 1997 and 2003 accused Iran of maintaining a stockpile of chemical weapons, these assessments largely changed after 2003. No effort has been made to take advantage of the challenge inspection mechanisms provided by the CWC to investigate purported Iranian chemical facilities. Moreover, none of the allegations made regarding the stockpiling of CW agents can be verified using information available in the unclassified domain.

Assessing Iran's CW capabilities is difficult—although there is an apparent wealth of information, very little of it constitutes original material. The greater part of published information on Iran's CW programs consists of repackaged information from a limited number of sources. The tendency to fit new information into a pre-existing framework that presumes the existence of a covert offensive CW program introduces additional problems. Ultimately, all public assessments of Iran's alleged CW program depend heavily upon information gathered from Iranian opposition groups and Western intelligence agencies. Doubts about the validity of information publicly released by Western intelligence agencies have increased since 2003 due to investigations that revealed selective reporting, the use of unreliable or biased sources, an unwillingness to emphasize uncertainty, and a failure to properly assess the veracity or reliability of available information.[1] Nonetheless, revelations since 2003 regarding the extent of Iran's previously concealed civilian nuclear program do raise the question of whether Iran might indeed be hiding a CW program. To piece together an objective overview of allegations surrounding Iran and its CW capabilities, the following profile mines open source literature while taking into consideration the above-mentioned problems and limitations.


Iran has a sophisticated base for the development of a chemical warfare (CW) program that dates back to the Iran-Iraq War (1980 to 1988) - a conflict that gave Iran strong incentives for developing a robust chemical defense capability. Several unclassified allegations and reports from the 1990s until approximately 2003 suggested that Iran had developed an offensive CW program. Many of these claims described specific military capabilities related to agent stockpiles, delivery systems, and deployments that cannot be independently verified in open sources. [2]

Instead, open source reports of Iranian transactions involving various dual-use materials have been interpreted as supporting claims for the existence of an offensive CW program. Iran has imported chemicals such as thiodyglycol and thionyl chloride that can be applied towards legitimate purposes such as dyes, textiles, and pesticides or could be diverted towards an illicit CW program. [3] In the mid-1990s, Iran also imported several tons of phosphorus pentasulfide, which is on the Australia Groups watch list for controlled chemical precursors, but not on the Chemical Weapons Convention (CWC) Schedule lists. [4] Although this compound has several legitimate uses, including pesticide production (most notably malathion), and as an additive for lubricant oil, it is also a starting point for the production of V-group nerve agents. [5] [6] Notably, U.S. intelligence estimates and State Department compliance reports between 2003 and 2010 do not list any specific CW agents possessed by Iran, and have removed all previous references to agent stockpiles or delivery systems. [7] These recent reports suggest that the U.S. intelligence community is either uncertain about or unwilling to publicly disclose the specifics of any Iranian offensive CW program.


1980 to 1988: Chemical weapons and the Iran-Iraq War

The Iran-Iraq War of 1980 to 1988 prompted Iran's involvement with chemical weapons. Beginning in 1983, Iran suffered the effects of increasingly effective Iraqi CW attacks, which initially involved blister agents (e.g. mustard gas), but later included nerve agents such as tabun and possibly sarin. [8] Estimates of the number of Iranian casualties from Iraqi CW use are not definitive, but the Iranian estimate is 60,000 casualties. [9]

The weak international response, particularly by the United Nations, to Iraqi use of chemical weapons against Iranian forces left Iran increasingly bitter about what it perceived to be a double standard in the enforcement of international agreements. Many Iranian officials concluded that their country had to develop the ability to retaliate in kind to deter chemical weapons use. In a 1987 interview, the Iranian representative to the United Nations (UN) stated that "...if the Iraqi regime does not take any steps in putting an end to the crimes of the Iraqi regime, we will retaliate in kind, and in that case, we will certainly announce it." [10] Some reports suggest that during the 1980s war with Iraq, Iran might have employed CW agents on a small scale between 1984 and 1988; however, an intensive review of the open literature (including UN reports based on field investigations from that era), has failed to support these allegations. [11]

While several Iranian leaders felt that developing a CW program would counteract the Iraqi threat and prove to be a strong deterrent, others within the clerical Islamic regime publicly condemned any use of chemical weapons on moral grounds, calling them un-Islamic. [12] However, there has been official confirmation that Iran pursued an offensive CW capability, at lease historically. In November 1998, Iranian Ambassador Mohammad R. Alborzi, director general of the Iranian Foreign Ministry, delivered a statement to the Conference of the States Parties (CSP) to the CWC in The Hague, Netherlands. In his statement, he admitted for the first time that Iran had once possessed CW, in the waning years of the Iran-Iraq War. But he claimed that, "...following the establishment of [the] cease fire, the decision to develop chemical weapons capabilities was reversed and the process was terminated." [13] In its initial declaration to the OPCW Iran declared a single chemical weapons production facility. The facility itself was reported as having been closed and demolished prior to the entry into force of the CWC for Iran, and OPCW  inspectors confirmed that the facility had been disabled. In addition to its offensive CW program, Iran appears to have maintained a robust defensive CW capability as an urgent military requirement.

1988 to 2003: Building a chemical warfare capability

Although Iran has admitted to pursuing an offensive CW capability, it has not provided any public accounting of the details of that program. As a result most evidence regarding Iran's initial pursuit of a CW capability must be extrapolated from instances when Iran imported bulk quantities of precursors for chemical warfare agents. According to Jane's, during the 1980s Germany allegedly exported dual-use chemical materials and technology to Iran. [14] The mustard gas precursor thiodiglycol was of particular interest to the Iranians. In 1989, U.S. authorities clamped down on the chemical company Alcolac International Inc., of Baltimore, Maryland, which illegally shipped almost 120 tons of thiodiglycol to Iran. [15]

India is also heavily implicated in exports of CW materials to Iran. The State Trading Corporation of India conceded in 1989 that it had sold over 60 tons of the nerve agent precursor thionyl chloride to Iran, and a shipment of an additional 257 tons was planned. [16] A decade later, the press reported chemical warfare implications in a 1997 multi-million dollar deal that India cut with Iran to construct an advanced chemical plant near Tehran, at Qazvim. [17] India was also purportedly involved in a botched sale to Iran of phosphorous pentasulfide, a chemical that could be utilized in pesticides or in the nerve agent VX. In 1998, reports indicated that China successfully concluded a similar arrangement with Iran for the sale of 500 tons of phosphorus pentasulfide. [18]

In the past, Jane's and other sources alleged that Chinese companies were involved in sales of CW technology to Iran; as a result, several Chinese companies and individuals have faced U.S. sanctions. In 1995, the U.S. State Department announced sanctions against Asian-Ways, Ltd., World Co (Hong Kong) Ltd., and Mainway International Ltd. for supplying Iran with "nerve gas technology." [19] According to U.S. press accounts citing a top secret CIA report dated 2 October 1996, China sold Iran nearly 400 metric tons of carbon disulfide, a precursor to riot control and nerve agents. [20] Despite these sales, there is no clear evidence that Iran has produced tear gas or other riot control agents. In 1997, the U.S. State Department sanctioned two additional Chinese companies for selling Iran CW-related precursors and equipment. [21]

In 2000, the U.S. government passed the Iran Nonproliferation Act, followed in 2005 by extended guidelines that led to the renaming of the measure to the Iran and Syria Nonproliferation Act. Pursuant to this act, the United States has sanctioned numerous entities and individuals in several countries, particularly India and China, for the export of dual-use materials to Iran.

In 2000, the CIA estimated that Iran "[possessed] a stockpile of at least several thousand metric tons of weaponized and bulk agent." [22] In 2002, a CIA unclassified report claimed that Iran's stockpile of CW agents reportedly included blister, blood, and choking agents, and possibly nerve agents. [23] According to several observers, Iran allegedly developed this capability with aid from Western individuals and companies, as well as from other nations, such as India and China. [24]

2003 to the Present: Changing Assessments

While Iran's history of possible CW-related imports suggests a possible offensive chemical weapons program, since 2003 U.S. intelligence assessments have refrained from definitive conclusions. Prior to that date, intelligence estimates included specific assessments of Iran's CW program, including the agents Iran allegedly stockpiled. The last of these more detailed reports, issued in 2003, stated that Iran "may have already stockpiled blister, blood, choking, and possibly nerve agents-and the bombs and artillery shells to deliver them-which it previously had manufactured." [25]

In 2004, however, the Director of National Intelligence stated that "Iran is a party to the CWC. Nevertheless, during the reporting period it continued to seek production technology, training, and expertise from foreign entities that could further Tehran's efforts to achieve an indigenous capability to produce nerve agents." [26] In 2007, the U.S. intelligence community stated that: "Iran maintains the capability to produce CW agent in times of need and conducts research that may have offensive applications." [27] Gone was the specificity that had been the hallmark of past U.S. intelligence assessments, suggesting at a minimum that the threat level was being reconsidered. [28] Subsequent reports have followed this general pattern. A 2011 CIA report of a similar nature assessed that "Tehran continues to seek dual-use technologies that could advance its capability to produce CW agents." [29] It furthermore judged that "Iran is capable of weaponizing CW agents in a variety of delivery systems," but gave not indication that Iran had done so. [30]

Iran has also apparently sought materials for a chemical weapons defense capability, which the CWC allows. In 1997 China sold Iran 40,000 barrels of calcium-hypochlorite, a chemical and biological decontaminating agent. [31] Iran also reportedly purchased respirators from Spain, protective gear from South Korea, and atropine auto-injectors from the Netherlands. [32]

Whether or not Iran has a stockpile of poison gas, Iran has extensive weaponry that could be adapted to deliver CW agents. In 1996, Jane's cited various reports that Iran had "developed 155mm artillery shells, mortar rounds, aerial bombs for chemical fill, and possibly chemical warheads for Scuds." [33] Jane's and other news outlets circulated reports that Iran utilized mines as delivery systems for chemical agents. [34] Iran's Shahab missile is also believed to be capable of carrying chemical warheads. [35] In 2002, Iran tested a new version of its Muajar-4 (Mohajer), an unmanned aerial vehicle, which some experts claim could be used for delivery of chemical or biological agents.

Iran also reportedly possesses a number of cruise missiles such as the Kh-55 Granat, which are well-suited to deliver chemical or biological warheads. Received from Ukraine in approximately 2001, these cruise missiles could conceivably be configured for the delivery of CW agents if Iran has attained the technological ability to fit the cruise missiles with chemical warheads, but experts debate whether Iran has the means to launch the actual missiles. [36] The September 2007 claims from Jane's and other international news sources that a CW-related explosion occurred at a Syrian military facility when Iranian and Syrian engineers attempted to fit a chemical warhead onto a Scud missile have been disputed. [37]

Current Status

Officially, Iran has consistently denied possession of chemical weapons. After the adoption of UN Security Council Resolution 1540 in April 2004, Iran continued to maintain that it did not possess such weapons. In a note to the UN Security Council in 2006 regarding its implementation of Resolution 1540, Iran's representatives stated that "the Islamic Republic of Iran, as a State party to all international legal instruments banning WMD, does not possess WMD and considers these kinds of weapons as inhumane, immoral, illegal, and against its very basic principles." [38] Within the framework of the CWC and under the auspices of the Organization for the Prohibition of Chemical Weapons, Iran has hosted training sessions on the medical aspects of chemical warfare. [39] In the international arena, Iran consistently points to its adherence to the CWC and denies any secret CW program.

Iran has continued to import potential CW agent precursors; however, since these chemical have legitimate civilian applications, such imports are by no means conclusive evidence that Iran is developing or maintaining a CW program. As of 2014, U.S. sanctions were still in effect against the Chinese firm Zibo Chemet Equipment Company. [40] Though the specific reason for the sanctions against Zibo Chemet is unclear, the company is "a major manufacturer of gas-lined chemical equipment." [41] Glass-lined, corrosion-resistant equipment was often employed in the production of CW agents, and at one time its use in the chemical industry was uncommon. Now, it is an increasingly important component in facilities for the production of pesticides and fertilizers using modern processes.

Despite a lack of evidence suggesting CW-related activities, many Western capitals view ongoing efforts to increase the size and sophistication of the Iranian chemical industry with suspicion. Past accusations, however, should be balanced against the dearth of reliable open source information, more recent and less definitive intelligence assessments, and the fact that CWC inspections of Iranian facilities have not revealed any evidence of an illicit Iranian CW program.

[1] The Commission on the Intelligence Capabilities of the United States Regarding Weapons of Mass Destruction: Report to the President of the United States (Washington, DC: U.S. Government Printing Office, March 31, 2005).
[2] See, for example, Office of the Secretary of Defense, Proliferation: Threat and Response (Washington, DC: Government Printing Office, 1995); and Russian Federation Foreign Intelligence Service, A New Challenge After the Cold War: Proliferation of Weapons of Mass Destruction, January 28, 1993.
[3] Sanjoy Hazarika, "India Says It Sold Iran a Chemical Used in Poison Gas," The New York Times, July 1, 1989, p. 1.
[4] Jane's, "Features: Iran's Chem-Bio Programmes," and Con Coughlin, "China Helps Iran to Make Nerve Gas," London Daily Telegraph, May 24, 1998, p. 1.
[5] U.S. Congress, Office of Technology Assessment, Technologies Underlying Weapons of Mass Destruction, OTA-BP-ISC-115 (Washington, DC: U.S. Government Printing Office, December 1993).
[6] Gerhard Bettermann, Werner Krause, Gerhard Riess, Thomas Hoffman, "Phosphorous Compounds, Inorganic," in Ulmann's Encyclopedia of Industrial Chemistry (Weinheim: Wiley-VCH, 2000).
[7] See, for example: U.S. Department of State, Bureau of Verification, Compliance, and Implementation, Adherence to and Compliance with Arms Control, Nonproliferation, and disarmament Agreements and Commitments, July 2014; and Deputy Director of National Intelligence for Analysis, "Unclassified Report to Congress on the Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions Covering January 1 to December 31, 2010," accessed June 30, 2011,
[8] Briefly, on chemical weapons use during the 1980s Iran-Iran War, Victor A. Utgoff, The Challenge of Chemical Weapons: An American Perspective (New York: St. Martin's Press, 1991), 80-86. At length on Iraqi use of chemical weapons during this conflict, Gordon M. Burke and Charles C. Flowerree, International Handbook on Chemical Weapons Proliferation (New York: Greenwood Press, 1991), 31-151.
[9] Javed Ali, "Chemical Weapons and the Iran-Iraq War: A Case Study in Noncompliance," The Nonproliferation Review, Spring 2001,
[10] Iranian diplomat was Rajai'e Korassani, as quoted in "Envoy to UN interviewed on Chemical Weapons Issues," Tehran Domestic Service in Persian, 22 April 1987, translated in FBIS-SAS-87-078, April 23, 1987, p. 11.
[11] U.S. Department of Defense, Proliferation: Threat and Response, November 25, 1997,
[12] Ali, "Chemical Weapons and the Iran-Iraq War: A Case Study in Noncompliance," Dilip Hiro, The Longest War: The Iran-Iraq Military Conflict (USA: Routledge, Chapman and Hall, Inc., 1991) and Peter Lavoy, et. al., Planning the Unthinkable: How New Powers Will Use Nuclear, Biological, and Chemical Weapons (New York: Cornell University Press, 2000).
[13] Itamar Eichner, "Iran Admits to Possessing Chemical Weapons," Yedi'ot Aharonot, November 20, 1998; FBIS Document FTS19981120000618, 20 November 1998; "Iran Pledges No Chemical Weapons Production," Agence France Presse, November 17, 1998; Mohammad R. Alborzi, "Statement to the Third Session of the Conference of the States Parties of the Chemical Weapons Convention," November 16-20, 2000.
[14] "Features: Iran's Chem-Bio Programmes," Jane's Chem-Bio Web, September 20, 2005,
[15] Jonathan B. Tucker, "Trafficking Networks for Chemical Weapons Precursors: Lessons from the Iran-Iraq War of the 1980s," Center for Nonproliferation Studies, November 2008, 10-22.
[16] Sanjoy Hazarika, "India Says It Sold Iran a Chemical Used in Poison Gas," The New York Times, July 1, 1989, p. 1.
[17] Con Coughlin Chief, "Iran in Secret Chemical Weapons Deal With India," Sunday Telegraph, June 24, 1996.
[18] Jane's, "Features: Iran's Chem-Bio Programmes," and Con Coughlin, "China Helps Iran to Make Nerve Gas," London Daily Telegraph, May 24, 1998, p. 1.
[19] Nicholas Ionides, Untitled, South China Morning Post (Hong Kong), April 27, 1995, p. 2.
[20] Bill Gertz, "China Sold Iran Missile Technology," Washington Times, November 21, 1996, p. 1.
[21] "U.S. Imposes CW Sanctions Against Chinese Entities, Statement by State Department Spokesman Nicholas Burns,", May 22, 1997,
[22] "Lauder Statement to Senate Committee on Foreign Relations," Central Intelligence Agency, October 5, 2000,
[23] "Unclassified Report to Congress on the Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions, January 1 through June 30, 2002," Central Intelligence Agency,
[24] Jonathan B. Tucker, "Trafficking Networks for Chemical Weapons Precursors: Lessons from the Iran-Iraq War of the 1980s," Center for Nonproliferation Studies, November 2008,; Sharon Squassoni, "India and Iran: WMD Proliferation Activities," CRS Report for Congress, November 8, 2006,; "Iran Denies Getting Help From China on Weapons," New York Times, May 25, 1997,
[25] "Unclassified Report to Congress on the Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions, July 1 - December 31, 2003," Central Intelligence Agency,
[26] "Unclassified Report to Congress on the Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions, January 1 - December 31, 2004," Director of National Intelligence, See also, "Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions, January 1 - December 31, 2005," Director of National Intelligence,
[27] "Unclassified Report to Congress on the Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions, Covering January 1 - December 31, 2007," Director of National Intelligence,
[28] Also see Markus Binder, "Iran's First-Generation Chemical Weapons Evaporate, as Certainty Declines in U.S. Intelligence Reports," WMD Insights, February 2008,
[29] "Unclassified Report to Congress on the Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions, January 1 - December 31, 2011," Director of National Intelligence,
[30] "Unclassified Report to Congress on the Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions, January 1 - December 31, 2011," Director of National Intelligence,
[31] Robert Karniol, "China Supplied Iran with Decontamination Agent," Jane's Defence Weekly, Vol 27, No. 17, p. 17.
[32] Robert Karniol, "China Supplied Iran with Decontamination Agent," Jane's Defence Weekly, Vol 27, No. 17, p. 17.
[33] Barbara Starr, "Iran Has Vast Stockpiles of CW Agents, Says CIA," Jane's Defence Weekly, August 14, 1996, 3.
[34] Bill Gertz, "China Aided Iran Chemical Arms," Washington Times, October 30, 1997, p. 1; Andrew Rathmell, "Iran's Weapons of Mass Destruction," Jane's Intelligence Review - Special Report No. 6, June 1995, p. 17.
[35] Bill Gertz, "Iran Tests Medium-Range Missile," Washington Times, July 23, 1998, p. 1; Bill Gertz, "Teheran Increases Range on Missiles," Washington Times, September 22, 1999.
[36] Paul Kerr, "Ukraine Admits Missile Transfers," Arms Control Today, Vol 35 (5), May 2005, 41, Anthony H. Cordesman and Adam C. Seitz, "Iranian Weapons of Mass Destruction: The Birth of a Regional Nuclear Arms Race?" (Santa Barbara: Praeger Security International, 2009) 131-132.
[37] James Hider and Michael Evans, "Blast at Secret Syrian Missile Site Kills Dozens," Times Online, September 20, 2007,
[38] United Nations Security Council, "Note Verbale Dated 14 February 2006 from the Permanent Mission of the Islamic Republic of Iran to the United Nations Addressed to the Chairman of the Committee," February 18, 2006,
[39] Claus-Peter Polster, "Ninth International Course on Medical Defence Against Chemical Weapons," Organization for the Prohibition of Chemical Weapons," November 9, 2008,
[40] Kenneth Katzman, "Iran Sanctions," Congressional Research Service, August 18, 2009,
[41] Zibo Chemet Equipment Company, "About,"; Charles R. Smith, "Chinese Firms Sanctioned," Newsmax, January 8, 2007,

Get the Facts on Iran
  • Negotiated a final Joint Comprehensive Plan of Action for its nuclear program w/ the P5+1 on July 14, 2015
  • Possesses complete uranium fuel cycle capabilities
  • Possesses short- and medium-range ballistic missiles

This material is produced independently for NTI by the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies at Monterey and does not necessarily reflect the opinions of and has not been independently verified by NTI or its directors, officers, employees, or agents. Copyright 2017.