The power of nuclear, chemical and biological weapons—all considered weapons of mass destruction (WMD)—does not necessarily rest solely in their destructiveness, but rather in the anxiety and fear that they create. WMDs can range from extremely complex weapons systems, where a high level of expertise is needed, to relatively unsophisticated munitions where only a minimal amount of scientific knowledge is required to create and employ them.
The Organization for the Prohibition of Chemical Weapons (OPCW), which works with the United Nations, was established in The Hague, Netherlands, in 1997 to ensure that chemical weapon (CW) stockpiles are destroyed and that CW precursors are tracked and monitored to prevent the rogue development of CWs. Although there are currently 189 member-states in the OPCW, Syria is not one of them. Syria deliberately chose not to join the OPCW and has not been held accountable for its CW arsenal in the past 16 years. As a result, the international community can only estimate the state and quantities of Syria’s CW stockpiles.
The U.S. government and other Western states have accused the Bashar al-Assad regime of using CWs against rebel forces and civilians in multiple incidents during the past six months, with the deadliest attack occurring in August 2013. The Syrian government, however, has denied these allegations. Russia, a Syrian ally, has claimed that Syrian rebels are to blame for the August CW attack. These disputes raise questions about the security of CW stockpiles, and there is concern that non-state actors could acquire CWs in Syria.
This article explores the CW dynamic of the Syrian civil war and the potential for non-state actors to acquire or employ these weapons. It finds that there is a risk, albeit an unlikely one, that non-state actors could gain control over a limited number of CWs in Syria. Yet the successful employment of CWs would prove difficult for a small terrorist organization.
Syria’s Porous Borders
The massive exodus of 1.5 million refugees from Syria during the course of the past two years is not only a humanitarian crisis but an illustration of Syria’s porous, uncontrolled borders. According to sources cited in the New York Times, U.S. counterterrorism officials estimate that there are more than 6,000 foreign fighters in rebel groups in Syria. Foreign fighters from countries such as the United Kingdom, Sweden, Jordan and Pakistan have moved across Syria’s weak borders to join jihadist rebel groups, some of which are associated with al-Qa`ida. Clearly, Syria has become a popular training ground for jihadist militants.
Abu Omar, a commander for al-Qa`ida’s Islamic State of Iraq and the Levant (ISIL), highlighted in an interview that the goals of his movement extend beyond Syria’s borders. He threatened Russia, and he talked of the broad-based fight against Shi`a Iran and its strategy to dominate the region. According to Omar, Sunnis from around the world are justified in traveling to Syria to fight with the rebels because the Syrian regime is deploying Shi`a fighters from Lebanon and Iraq. Other groups such as Jabhat al-Nusra, which also has ties to al-Qa`ida, have been identified as fighting alongside mainstream fighters who identify themselves with the Free Syrian Army (FSA).
Abu Omar’s comments reveal the paradox of the Syrian civil war and the role of foreign fighters. The al-Assad government is bolstered by Lebanese Hizb Allah while the ranks of the FSA include some fighters whose allegiance is solely to Sunni Muslims, rather than to nationalist or democratic ideals. For those like the ISIL’s Abu Omar, the civil war in Syria is a sectarian war pitting Sunni Muslims against regime Alawites and their Shi`a Muslim backers in Iran and Hizb Allah.
This illustrates why Syria’s porous borders represent a threat to the region. The Syrian border is regularly crossed by fleeing refugees, rebel fighters and pro-Assad non-state actors. Shi`a Hizb Allah, for example, has crossed into Syria from Lebanon and has fought for the al-Assad regime, particularly in the town of Qusayr in Homs Province. Westerners and other Sunni foreign fighters have entered Syria—probably from Turkey—to fight with jihadist groups such as Jabhat al-Nusra, the ISIL or Jund al-Sham.
Weak border security also raises the concern that CWs—if acquired by non-state actors—could be smuggled out of Syria and employed against regional targets or Western interests.
There are three potential ways that non-state actors could acquire CWs: military success, proliferation by the Syrian regime, or regime defectors.
The most transparent means for non-state actors to gain control over CWs is military success. The rebels have launched large, coordinated attacks against al-Assad’s military facilities, and it is possible that they could overtake a CW storage site. Yet these attacks are frequently covered by international media who are embedded within the units, and they are certainly monitored by various international intelligence agencies. If rebels were to attack a facility known to store CWs, it would likely be discovered by concerned entities—such as the U.S. intelligence community—who might be able to enact contingency operations to prevent the spread of CWs. Nevertheless, recent reporting by the Wall Street Journal and other media outlets indicates that the al-Assad regime has not been storing the CWs in centralized locations, but instead “moving the stocks around for months to help avoid detection.” Dispersion of the CW stockpiles would make it difficult for the international community to know precisely where the weapons are located. The CW stockpiles, however, are also al-Assad’s bargaining chip in staving off foreign intervention, so it is unlikely that he would compromise the security of such weapons.
The second possible way for non-state actors to gain access to CWs is if the Syrian regime provides the weapons to a group such as Hizb Allah. This concept of “indebtedness” suggests that the al-Assad regime could hypothetically give Hizb Allah CWs to maintain their current or future support, or in an effort to hide CWs from international inspectors. In September 2013, U.S. Secretary of Defense Chuck Hagel warned that “if Assad is prepared to use chemical weapons against his own people, we have to be concerned that terrorist groups like Hezbollah, which has forces in Syria supporting the Assad regime, could acquire and would use them.”
The third possibility, which is perhaps the least likely, is for defectors within the Syrian military and government to alter the balance of the war by providing weapons such as CWs to rebel groups. Yet significant acquisition challenges would remain. The Syrian regime has likely established accountability redundancies, and more than one person would be required to oversee the movement of a CW. General security procedures, for example, would prevent a soldier at a military storage site from moving a handful of CW rounds to his vehicle and driving off.
Chemical weapons can be disseminated in multiple forms including gases, liquids, and solids. These poisons are designed to be lethal and highly toxic. To affect large populations in open areas, however, CW agents must be delivered in large doses. Weather conditions—such as wind direction, temperature, and population density—affect the delivery of chemical agents. A vehicle-borne improvised explosive device laden with a chemical agent consequently would have limited success, whereas delivery of an agent in a confined space, such as in an arena or office building, could affect thousands.
The delivery concepts of CWs are relatively basic. The Aum Shinrikyo Sarin attack on the Tokyo subway in 1995 highlighted the intensity and amount of casualties expected by a CW attack employed by a small terrorist group in an enclosed space, as opposed to the massive amounts used against soldiers on World War One French battlefields. The Tokyo subway attack, which killed 13 and injured more than 5,000, also showed how dissemination does not require complex delivery systems, as would be required for biological weapons. CWs are designed to have a high boiling point so that an exploding shell does not destroy the chemical agent, although there are complex processes required when using a binary CW agent. Some binary agents need to be mixed in advance of being loaded into a delivery system, such as a shell, while others are self-mixing where the detonation of the shell automatically mixes the precursors stored within it.
To maintain potency, CWs require unique handling and storage. CW agents are corrosive and degrade their own storage containers over time. A shell containing Sarin removed from its controlled storage environment would immediately begin degrading the seals of the container in the shell. The vapor pressure in the container would also drastically increase as well as the acidity of the CW with increasing temperature. Since it is unlikely that a terrorist organization would have access to aircraft, it would be limited to using trucks or cars along hot, dusty roads to leave Syria. A terrorist organization, without proper protective equipment, would be restricted in the range it could transport a CW as the agent could potentially kill those moving it. A terrorist group would be constrained to targeting regional actors unless provided sophisticated storage and transport capabilities.
Hizb Allah and Al-Qa`ida
Two groups that might be interested in acquiring CWs include Hizb Allah and al-Qa`ida.
Although Hizb Allah is a non-state actor, the group plays a major role in Lebanese politics and operates openly in southern Lebanon. Consequently, Hizb Allah might determine that such weapons are best used as deterrence against a repeat of Israel’s invasion of Lebanon in 2006, rather than in an offensive capacity which might invite a strong international response. Nevertheless, Israel’s security doctrine suggests it would take immediate military action to prevent Hizb Allah from acquiring CWs.
Al-Qa`ida, on the other hand, operates clandestinely and is not based in any one state. It has shown a prior interest in CWs, and U.S. security officials operate under the assumption that al-Qa`ida would use CWs if it acquired them. There is evidence that al-Qa`ida experimented with crude chemical weapons in the past, and the group even had a chemical and biological weapons expert, Abu Khabab al-Masri, who was killed by a U.S. drone in 2009. Moreover, al-Qa`ida in Iraq used the chemical chlorine in more than a dozen bombs in 2007. Director of National Intelligence James Clapper told Congress in January 2012 that the U.S. intelligence community worries “about a limited CBR [chemical, biological and radiological] attack in the United States or against our interests overseas in the next year because of the interest expressed in such a capability by some foreign groups, such as al-Qa`ida in the Arabian Peninsula (AQAP).”
Yet due to the restrictions in transporting CWs, al-Qa`ida would most likely be limited to a target in the immediate Middle East region. Regardless of the target, a successful CW attack could further destabilize a region already struggling to define itself in the wake of the Arab Spring uprisings. A CW attack on Western interests—such as an embassy—within any country in the region might increase the legitimacy of a terrorist group among its supporters, and force Western governments to reevaluate the threat picture.
In a positive development, the Syrian government provided “an initial declaration” of its chemical weapons program on September 20, the first step in a U.S.-Russian deal for Syria to relinquish its CW stockpiles. Yet until it becomes clear that the Syrian regime is committed to the agreement—especially in light of recent reports that it is continuously moving around its CW stockpiles—the risk for proliferation remains.
Captain Stephen Hummel is a FA52 officer currently studying Chemical and Physical Biology at Vanderbilt University as part of the Army’s Advance Civil Schooling Program. CPT Hummel previously served in both Iraq and Afghanistan as well as served as the USAREUR CBRN plans officer. Upon graduation at Vanderbilt, he will teach in the Chemistry and Life Science Department at the U.S. Military Academy, West Point. The viewpoints expressed in this article do not necessarily reflect those of the U.S. Army or the Department of Defense.
 Dana Hughes, Z. Byron Wolf, and Mary Bruce, “US Confirms Syrian Government Used Chemical Weapons,” ABC News, June 13, 2013; Ben Hubbard, “Signs of Chemical Attack Detailed by Aid Group,” New York Times, August 24, 2013.
 “UN Chemical Weapons Inspectors to Visit Syrian Sites,” BBC, July 31, 2013.
 In September 2013, U.S. Secretary of Defense Chuck Hagel warned, “The Syrian regime’s use of chemical weapons poses grave risks to our friends and partners along Syria’s borders including Israel, Jordan, Turkey, Lebanon and Iraq. If Assad is prepared to use chemical weapons against his own people, we have to be concerned that terrorist groups like Hezbollah, which has forces in Syria supporting the Assad regime, could acquire and would use them. That risk of chemical weapons proliferation poses a direct threat to our friends and partners, and to U.S. personnel in the region. We cannot afford for Hezbollah or any terrorist group determined to strike the United States to have incentives to acquire or use chemical weapons.” For his full statement, see Chuck Hagel, “Statement on Syria Before the Senate Foreign Relations Committee,” U.S. Department of Defense, September 3, 2013. In March 2013, Director of National Intelligence James Clapper testified before Congress that the intelligence community is concerned that “nongovernmental groups or individuals in Syria could also gain access to such materials [chemical weapons].” For Clapper’s full statement, see James R. Clapper, “Worldwide Threat Assessment to the Senate Select Committee on Intelligence,” Office of the Director of National Intelligence, March 12, 2013. Also see a report by senior British lawmakers in which they warned that “there has to be a significant risk that some of the country’s chemical weapons stockpile could fall into the hands of those with links to terrorism, in Syria or elsewhere in the region—if this happens, the consequences could be catastrophic.” For details, see “Risk of Chemical Catastrophe if Syria’s Assad Goes: UK Lawmakers,” Reuters, July 10, 2013.
 “Syria Regional Refugee Response,” United Nations High Commissioner for Refugees, August 19, 2013.
 Anne Barnard and Eric Schmitt, “As Foreign Fighters Flood Syria, Fears of a New Extremist Haven,” New York Times, August 8, 2013.
 Ibid.; “Risk of Chemical Catastrophe if Syria’s Assad Goes: UK Lawmakers.”
 Barnard et al.
 Bill Roggio, “Al Nasrah Front Launches Joint Assaults with Numerous Syrian Rebel Groups,” The Long War Journal, July 31, 2013; Josh Wood, “Jihadi Group Says it Stands with Other Syrian Rebels,” New York Times, January 9, 2013.
 The 17-day battle for Qusayr between Syrian government and Hizb Allah forces against the opposition forced the rebels to abandon the town and marked a major victory for the al-Assad regime. For details, see Nicholas Blanford, “The Battle for Qusayr: How the Syrian Regime and Hizb Allah Tipped the Balance,” CTC Sentinel 6:8 (2013).
 For a list of a few alleged foreign fighters, see Elias Groll, “PSA To Prospective Jihadists: The FBI Will Prosecute You if You Join Jabhat al-Nusra,” Foreign Policy, May 31, 2013. New York Times journalist Jeffrey Gettleman reported in July 2012 that “it seems the Antakya area [in Turkey] is becoming a magnet for foreign jihadis, who are flocking into Turkey to fight a holy war in Syria.” See Jeffrey Gettleman, “Fighters Replace Tourists Crossing Over From Syria to an Idyllic Turkish Town,” New York Times, July 28, 2012. For evidence of Swedish foreign fighters, see Per Gudmundson, “The Swedish Foreign Fighter Contingent in Syria,” CTC Sentinel 6:9 (2013); Misbah al-Ali and Antoine Amrieh, “Lebanese Suicide Bomber’s Family Celebrates Death of Kin in Syria,” Daily Star, August 5, 2013. Also see Barnard et al.
 Adam Entous, Julian Barnes, and Nour Malas, “Elite Syrian Unit Scatters Chemical Arms Stockpile,” Wall Street Journal, September 12, 2013.
 Jay Solomon, “Disarmament Talks Begin on Shaky Ground,” Wall Street Journal, September 13, 2013.
 Yaara Shalom, “Report: Syria is Transferring Chemical Weapons to Hezbollah to Avoid International Inspection,” Jerusalem Post, September 16, 2013.
 Hagel. On September 16, 2013, a Lebanese member of parliament even went so far as to claim—albeit without presenting any evidence—that the al-Assad regime had already given Hizb Allah CWs to be stored in Hizb Allah-controlled mountain areas of Lebanon, where it would be difficult to find or monitor them. His claim is likely unsubstantiated rhetoric, but it shows the heightened concerns about Syria’s CWs. For details, see ibid.
 A number of Syrian officials have already defected to the rebels, the most prominent of whom is former Syrian Air Force Colonel Riad al-Asaad, who formed the FSA. A report in the Daily Beast told the story of Obeidah al-Mustafa, a former Syrian Army lieutenant who defected in 2012 and now leads the Liwa al-Fathin rebel brigade in Damascus. Al-Mustafa said that he is trying to facilitate more defections. See Mike Giglio, “Fearful of a U.S. Strike, Defectors Flee the Syrian Army,” Daily Beast, September 5, 2013. Moreover, according to a Reuters report, which cited former Syrian soldiers, “military sites in Syria are packed with soldiers who have been effectively imprisoned by their superiors due to doubts about their loyalty…Most of the commanding officers are from Assad’s Alawite sect, an off-shoot of Shi’ite Islam, and fear their subordinates will defect, flee their posts or coordinate with rebel units…” See Oliver Holmes and Khaled Yacoub Oweis, “Exclusive: Syria Army Defectors Say U.S. Strikes Could Kill Assad Opponents,” Reuters, August 30, 2013.
 Chemical weapons in a solid state will, depending on environmental conditions such as temperature and humidity, “off-gas” as their state changes from either solid to liquid or directly solid to gas.
 In the case of a car bomb, the deadly gas from a CW would be disseminated by both the explosion and the wind, but it would need to be of high quantities to be effective.
 Melissa Locker, “Tokyo Sarin Gas Attack Suspect Arrested, 17 Years Later,” Time, June 4, 2012.
 Biological weapons (BW) are living organisms. Therefore, they require more complex delivery systems that are capable of dispersing the agent over a widespread area without destroying the agent. BW are not capable of withstanding the heat and pressure caused by an exploding ordinance like CWs.
 Most containers are not 100% steel. There needs to be a rubber plug or epoxy to create a complete seal. These seals are quickly degraded once a gas such as Sarin is removed from its storage unit. There are other factors at play as well, not mentioned in this article.
 Blue Grass Army Depot in Kentucky has spent years cleaning up and repairing CW munitions that had spent their lifetime in controlled, secure environments so that they can simply transport the weapons to a neutralizing facility for destruction. See “Chemical Weapon Meltdown,” PEEReview, 2007; “Meeting Summary,” Kentucky Chemical Destruction Community Advisory Board, October 4, 2004.
 For a profile of Hizb Allah and its role in Lebanese politics, see Jonathan Masters, “Hezbollah,” Council on Foreign Relations, July 22, 2013.
 Yuval Steinitz, Israel’s international relations, intelligence and strategic affairs minister, said that Israel “has drawn a red line over the transfer of chemical weapons to terrorist organizations, including Hezbollah.” See Yaakov Lappin, “Steinitz: Israel Can See if Assad is Moving Syria’s Chemical Weapons,” Jerusalem Post, September 15, 2013. For more details on Israel’s security doctrine, see Arie Perliger, “Israel’s Response to the Crisis in Syria,” CTC Sentinel 6:8 (2013).
 An argument can be made that there is not enough evidence to prove that al-Qa`ida would employ CWs if it acquired that capability. According to this reasoning, al-Qa`ida (or an affiliated group) would refrain from using CWs due to concerns that such use would cause a
loss of support. Regardless, the U.S. intelligence community and law enforcement clearly consider this outcome a possibility and prepare accordingly.
 Barton Gellman, “Al Qaeda Nears Biological, Chemical Arms Production,” Washington Post, March 23, 2003.
 Farhan Bokhari, “Officials: Al Qaeda’s Mad Scientist Killed,” CBS News, September 10, 2009.
 There should be a distinction, however, between chlorine bombs and CWs such as the one used by Aum Shinrikyo on the Tokyo subway in 1995. Chlorine is a toxic industrial chemical and not a true CW. For details, see “‘Chlorine Bomb’ Hits Iraq Village,” BBC, May 16, 2007; Peter Bergen, “Reevaluating Al-Qa`ida’s Weapons of Mass Destruction Capabilities,” CTC Sentinel 3:9 (2010).
 James R. Clapper, “Unclassified Statement for the Record on the Worldwide Threat Assessment of the US Intelligence Community for the Senate Select Committee on Intelligence,” Office of the Director of National Intelligence, January 31, 2012. Also see a recent report that three men charged with being members of al-Shabab, an al-Qa`ida affiliate, “had substantial knowledge regarding an al-Shabaab research and development department that was developing chemical weapons.” See “Court Document References Al Qaeda-linked Chemical Weapons Program in Somalia,” CBS, September 19, 2013.
 Michael R. Gordon and Nick Cumming-Bruce, “Syria Meets its First Test of Accord on Weapons,” New York Times, September 20, 2013.
 On September 23, 2013, al-Assad said that inspectors might have a difficult time accessing CW sites because “militants might want to stop the experts’ arrival.” See “Assad: Syria Will Allow Access to Chemical Sites,” Associated Press, September 23, 2013; Entous et al.