In the early morning of July 26, 2007, an explosion occurred at a Syrian military facility on the outskirts of the city of Aleppo (Halab). The explosion killed 15 Syrian military personnel and injured at least 50 others. News of the explosion was quickly reported by Syrian state-controlled media.

Initial unofficial reports described the incident as “[the] explosion of one or more gas cylinders at the time of breakfast.” [1] Presumably these cylinders contained propane or some other flammable gas. The initial reports were soon corrected, and official Syrian descriptions of the event stated that “an explosion took place in an explosive materials warehouse of a military unit in the Aleppo Governorate, due to a reaction of highly explosive sensitive material caused by an excessive rise in temperatures, resulting in the combustion of the stored materials.” [2] The story attracted some initial attention in the Arab media and was picked up by wire services and CNN, but media interest in the event soon faded. [3]

Jane’s Claims Syria Testing Chemical Warhead
In late September 2007, Jane’s Defence Weekly ran a story claiming to reveal new details about the event and its consequences. [4] Rejecting the official Syrian explanations, Jane’s asserts that the explosion resulted from a fire ignited by an accident during weaponization tests of a chemical warhead for Syria’s Scud missile arsenal. When the fire and explosion occurred, the account states, Iranian technicians were reportedly engaged in fitting a warhead filled with distilled mustard (HD) to a Scud-C missile. Quoting “Syrian defense sources,” Jane’s claims that “[t]he explosion occurred when fuel caught alight in the missile production laboratory. The blast dispersed chemical agents (including VX and Sarin nerve agents and mustard blister agent) across the storage facility and outside.” [5] The story also claims that 15 Syrian military personnel and “‘dozens’ of Iranian missile weaponization engineers” were killed in the incident. The report further claims that “other Iranian engineers were seriously injured with chemical burns to exposed body parts not protected by safety overalls.” [6] The site of the events described is presumably the Al-Safir chemical weapon (CW) and missile facility southwest of Aleppo. [7] Iran and Syria signed a mutual defense pact in February 2005, both deploy Scud missiles, and both are suspected of possessing chemical weapons, suggesting that Iranian technicians would have been present at the Syrian site to further a joint project of some type involving these capabilities. [8] (For additional background on Syrian missile capabilities and Iranian involvement in the Syrian missile program, see “Israel Sees Growing Missile Threat from Syria,” WMD Insights, July/August 2007.)

The Jane’s report attracted considerable attention and served as the basis for numerous additional reports. The Israeli news-site YNet News added some new details, claiming that the fire that triggered the explosion began in the missile’s engine. [9] On September 24, Rawstory, a news website, described the incident in terms that were somewhat at variance with those in the Jane’s report. [10] According to Rawstory, “North Korean scientists working with Syrian military and intelligence officials attempted to load a chemical warhead onto one of the North Korean missiles, likely the No-dong 1 model …. The result was an explosion that killed a few of those present and, according to some official reports of the blast, as many as 50 civilians.” The Rawstory report did not mention Iranian personnel; it also asserted that the warhead at the center of the explosion contained Sarin rather than mustard. In early October, a Tokyo Sankei Shimbun article added another new detail: it reported that three North Korean technicians were killed in an explosion resulting from a “combustion test” of a Scud missile. [11] The Sankei Shimbun article added no new information about the role of chemical weapons in the incident; simply repeating the content of the original Jane’s report.

Despite its wide distribution, the Jane’s report did not attract any official confirmations. The report relies solely on “Syrian defense sources” without adding any input from U.S. or Israeli intelligence sources. [12] The only comment on the incident by an official U.S. source was a statement by the press secretary of the U.S. Department of Defense that he had not seen any recent credible evidence that Syria was developing chemical weapons. [13] W. Patrick Lang, a former senior official at the Defense Intelligence Agency (DIA), questioned the veracity of the Jane’s report, saying he thought it was unlikely that a Syrian defense official would reveal information about the country’s chemical weapons program. [14]

The central point of the Jane’s article is that the incident confirms information, previously published in Jane’s Defence Weekly, that “Syria and Iran have been advancing a costly CW project for more than two years as part of the[ir] strategic co-operation accord.” [15] However, the Jane’s story contains a number of points that are not fully persuasive and raise several questions.

Is Jane’s Claim of a CW Accident Accurate?
The Jane’s article states that fuel caught fire in a missile production laboratory where a mustard warhead was being fitted to a Scud-C missile, triggering an explosion that “dispersed chemical agents (including VX and Sarin nerve agents and mustard blister agent) across the [adjacent CW] storage facility and outside.” [16]

This description contains a number of questionable elements that either point to problems with the source information or to severe deficiencies in the management of the Syrian missile and CW programs. It appears that the weaponization test, perhaps a fit test for a new warhead design or a mating exercise using an existing design, was being conducted in the missile production laboratory. However, it not clear why a warhead filled with live CW agent was required for this test, when an inert simulant would have been equally suitable and far safer. Although the Syrians are reported to have engaged in live agent tests in the past, more recent missile tests have involved the use of CW simulants. [17] The article, moreover, clearly implies that many of the personnel injured during the incident were not wearing full chemical protective gear, even though the test supposedly involved the use of live CW agents. It is also unclear why so many personnel would be close enough to a mustard-filled warhead that several dozen might be killed and up to 50 injured. The fact that the explosive burster component of a CW warhead is much less powerful than a conventional high explosive (HE) warhead would tend to reduce, though certainly not eliminate, the potential for death and injury; moreover, exposure to mustard is not usually fatal. Furthermore, it would be normal practice to minimize the number of personnel close to a missile during a hazardous operation such as fitting a warhead.

The Jane’s article clearly states that the ignition of missile fuel was the source of the explosion, without providing any explanation of why highly volatile missile fuel, and presumably an oxidizer needed for the fuel to combust after launch, was present in the laboratory at the time of the warhead fitting or mating test. Carrying out such a test in the presence of fuels or oxidizers that are not specifically required for the test would be unusual for a liquid-fueled missile, since liquid fuels, as opposed to a solid fuels, are usually loaded at the time of launch. [18] This anomaly suggests, if the Jane’s report is accurate, that either the warhead was being mounted on a fueled missile, an unusual situation that would need to be explained, or that there was an accident during the process of fueling or firing the missile after the warhead had been mounted.

Scud missiles use either Unsymmetrical Dimethyl Hydrazine (UMDH) or refined kerosene as a fuel, and Inhibited Red Fuming Nitric Acid (IRFNA) as an oxidizer. UMDH and IRFNA are both extremely dangerous chemicals that are highly corrosive to skin and other tissues. Soviet Scud missiles used UMDH as a fuel and the available evidence suggests that Syria’s Scud-Cs also use UMDH. [19] The fuel/oxidizer combination is hypergolic, meaning that the two chemicals ignite on contact. The medical effects of exposure to IRFNA are similar to those of mustard gas and might be the source for the Jane’s claims that personnel were exposed to mustard. [20] Moreover, any errors or accidents associated with the handling of UMDH and IRFNA could easily result in a serious fire or even an explosion that could kill or injure nearby personnel. The YNet News article reported that the fire “started in the missile’s engine,” while the Tokyo Sankei Shimbun article linked the explosion to a “combustion test.” [21] On the basis of available evidence, it seems reasonable to conclude that a major component of the explosion was missile fuel, some of which might have contaminated the immediate area.

Finally, it is unclear why quantities of mustard, Sarin, and VX would all have been dispersed as a result of an explosion in a missile production laboratory, as Jane’s reports, when, supposedly, only a mustard warhead was being fitted. The article does not suggest that the explosion involved the CW storage facility, only that the installation where the explosion occurred had stored CW agents in dispersed locations on the site. Previously published information on the alleged Syrian missile and CW facility at Aleppo, including satellite imagery, indicates that Syria has constructed a number of separate buried storage bunkers for its CW stockpile. [22] According to Jane’s, the weaponization test involved mustard agent; thus, it would appear that Sarin and VX were being stored inside the laboratory for some other purpose in sufficiently close proximity to each other and to the source of the explosion that both could be dispersed as the result of a single accident. If accurate, Jane’s report suggests a remarkable degree of carelessness on the part of Syrian technicians in handling extremely toxic substances.

Another anomaly worth noting in the Jane’s report is that mustard was being used to fill the Scud warhead, rather than VX, which, like mustard, is a persistent CW agent, but is far more lethal. Since Scuds are inaccurate, it is generally assumed that they would be used against enemy cities, rather than military targets. Presumably a state with stockpiles of both mustard and VX would select the more deadly alternative for denying terrain and inspiring terror. [23]

Moreover, the reference to VX in this incident may not be accurate, as it is unclear whether Syria has actually produced or deployed VX. Various intelligence sources have been quoted as stating on a number of occasions that Syria has begun production of VX or has a deployed arsenal of VX. [24] On the other hand, in publicly released assessments of the Syrian CW program, the Central Intelligence Agency has regularly stated that Syria already has a “stockpile of the nerve agent Sarin, but apparently has tried to develop a more toxic and persistent nerve agent,” generally understood to be VX and clearly implying that this effort had not yet succeeded. [25] Both the Jane’s and Rawstory articles report that the explosion released Sarin. The Jane’s article provides no explanation for this release, whereas the Rawstory article claims that the chemical warhead was filled with Sarin rather than mustard, as stated in the Jane’s story. [26] In neither case, however, is there clear evidence to substantiate the claim of a CW agent release.

Conclusion
The claims made by Jane’s Defence Weekly for the release of chemical warfare agents are difficult to substantiate. The discrepancy between Jane’s and Rawstory as to the CW agent released is interesting and suggests the possible existence of a second anonymous source regarding the event, in addition to the one upon which Jane’s relied, but it does not allow a determination as to the accuracy of either claim. Regardless of the CW agent involved, it is possible that a fire and explosion during the mounting of a filled CW warhead could result in a release of CW agent. However, it is extremely difficult to understand how such an accident would result in the release of three different types of CW agent, as suggested by Jane’s. The lack of official statements from the United States or Israel supporting the claims of CW agent release or of the deaths of large numbers of Iranian technicians also raises questions about the accuracy of the story. It is equally difficult to render any judgment regarding the claims that North Korean personnel were killed in this incident.

Based solely on the information provided in public reports, it is hard to dispute that a large explosion occurred at a Syrian military facility in the vicinity of Aleppo on July 26, 2007. In light of the often conflicting evidence, it seems most likely that the event involved more than admitted in the official Syrian statement that the explosion was the result of an accident associated with the testing of a Scud-C missile. Although the exact details of the event are unclear, it seems likely that there was a problem either with the handling of the missile’s hypergolic fuels or related to the firing of the missile engine, but that CW agents were not involved. This interpretation fits the reports in the Tokyo Sankei Shimbun, YNet News, and Rawstory, all of which refer to problems with the missile itself, and is also consistent with the injuries described in the Jane’s article, which may well have been the result of the accidental release of highly toxic Scud missile fuel or oxidizer.

It is not possible to determine the credibility of allegations that Iranian or North Korean technicians were present at the time of the explosion. With respect to the possible presence of Iranian personnel, Jean Pascal Zanders, a Geneva-based expert, has pointed out in an online commentary that, if Iranians were involved in the process of fitting a chemical warhead to a missile, Iran would be in breach of the Chemical Weapons Convention (CWC), to which it (but not Syria or North Korea) is a party. [27]

Whether the warhead in the event was empty or filled is unimportant, as Article II of the Chemical Weapons Convention defines a CW [chemical weapon] together or separately as (i) the toxic agent, (ii) munitions and devices to be used with such toxic agent, and (iii) any other equipment to be used in relationship to such munitions and devices (which can mean the missile body as well as filling equipment, among many other things). [28]