Background

Questioninfo icon

Who carried out the chemical attack in Ghouta on August 21, 2013?

Answerinfo icon

Opposition forces in Syria (

Liwa al-Islam
) carried out the chemical attack.

(96% probability)

Backgroundinfo icon

On August 21, 2013, rockets with chemical payloads landed around the neighborhood of Zamalka, located in Ghouta (an agricultural area outside of Damascus), resulting in hundreds of civilian casualties. A UN team visited the area and confirmed that the rockets carried sarin, a deadly nerve agent used as a chemical weapon.

There was initial skepticism that the Syrian government would have ordered such an attack, risking retaliation by the US. But information published by the US, UN, and Human Rights Watch during the following weeks convinced Western public opinion that the Syrian government was indeed responsible. This information included:

  1. Proof that the volcano rockets found in Zamalka were locally manufactured by the government.
  2. Rocket trajectories reported by the UN that were shown to intersect at a Syrian army base.
  3. Detection of sarin, which was known to be held by the Syrian government.
  4. Reports by the US government that the rockets had been launched from government territory.
  5. Finally, Syria’s agreement to dismantle their chemical weapons program was further seen as an admission of guilt. At that point the issue mostly disappeared from public discourse.

However, over time, some of this evidence has been found to be unreliable, while new evidence has surfaced that seems to better support the hypothesis that opposition forces were behind the attack. These include:

  1. Analysis of the rocket’s range showing that it could not have been launched from the army base initially suspected as the origin.
  2. Errors in the UN trajectory calculations that, together with the new rocket range calculation, point to a launch from opposition territory.
  3. Evidence of multiple instances in which the opposition used sarin or tried to acquire it.
  4. Videos apparently showing an opposition group (Liwa al-Islam) launching chemical rockets, which match the time and location of the attack on Ghouta.

This attack, and others that followed, are the subject of heated international debate, which significantly increased the risk of a US-Russian military conflict on at least three occasions. The world clearly needs an unbiased analysis of this case using advanced inference tools.

Update: In June 2021, the videos of the event were corroborated as authentic. They were matched to a field within opposition controlled territory, and that field has been shown to be in the intersection of seven trajectories calculated from images of the impact sites. See additional evidence.

We now consider this issue closed, and no longer see a need for a probabilistic analysis, as the new discoveries are clear enough to understand using standard human reasoning. We're leaving the analysis here for reference, and recording our original estimate: 87% Opposition, 13% Syrian army.

Note: While we don’t expect anyone to apply at this point, the Rootclaim $100,000 debate challenge is still available for this issue. Read more here.

Hypotheses Consideredinfo icon

Calculated Resultsinfo icon

Calculated Resultsinfo icon

1

96.4%
Opposition:

Opposition forces in Syria (

Liwa al-Islam
) carried out the chemical attack.

96.4%

2

3.6%
Syrian army:

The Syrian army carried out the chemical attack.

3.6%

Starting Pointinfo icon

Initial Probabilities

Name
Initial Likelihoods
info icon
Syrian army
67%
Opposition
33%

The few prior instances of chemical attacks against civilian targets contain factors that make them poor comparisons to the attack in Syria, leaving motivation as the primary factor. An analysis of the motivating factors behind such an attack results in the Syrian army being twice as likely to launch such an attack compared to an Opposition group, i.e. 67%-33%.

Name
Initial Likelihoods
info icon
Syrian army
67%
Opposition
33%

Evidenceinfo icon

Effectinfo icon

Sarin

Name

Effectinfo icon

Updated Likelihoods

Syrian army
×9
95%
Opposition
-
5%

The attack was carried out using a large amount of sarin, which was known to be contained in the Syrian army’s stockpile. There are indications that the sarin contained the chemical hexamine, which was declared by Syria as being part of its chemical weapons program. 

On the other hand, opposition forces were trying to obtain chemicals in order to produce sarin, and they released videos threatening chemical attacks. They could have stolen the sarin from the Syrian army, which would explain why it contained hexamine, or could have manufactured sarin themselves using a similar process. Although no opposition stockpiles of sarin were found, Syrian army soldiers were attacked by sarin multiple times, including in the days following the attack on Ghouta, meaning that opposition forces probably had access to sarin at that time.

Name

Effectinfo icon

Updated Likelihoods

Syrian army
×9
95%
Opposition
-
5%

Volcano rockets

Name

Effectinfo icon

Updated Likelihoods

Syrian army
-
95%
Opposition
×1
5%

The sarin was delivered via

volcano rockets
, which were produced and used by the Syrian army. However, opposition forces could have stolen those rockets from the Syrian army along with other munitions they acquired. Additionally, while the Syrian army carried out previous conventional attacks using
volcano rockets
, they were not declared as part of the Syrian chemical weapons program and are inferior to other rocket options available.

Name

Effectinfo icon

Updated Likelihoods

Syrian army
-
95%
Opposition
×1
5%

Purported video of the event

Name

Effectinfo icon

Updated Likelihoods

Syrian army
-
69%
Opposition
×8
31%

Videos of

Liwa al-Islam
fighters wearing chemical protection gear while firing
volcano rockets
and artillery shells in the Ghouta area were allegedly taped the night of the chemical attack. Multiple aspects of the video are uncharacteristic of a fabrication, such as it containing many irrelevant details, requiring a thorough analysis to understand its contents, and not having any slip-ups.

Name

Effectinfo icon

Updated Likelihoods

Syrian army
-
69%
Opposition
×8
31%

Launch location

Name

Effectinfo icon

Updated Likelihoods

Syrian army
÷3
7%
Opposition
×15
93%

Based on the range of the rockets, the location that they struck, and the impact direction upon landing, the launch location was a small field in Qaboun (33.5325°, 36.3412°), 2 km northwest of the impact sites in Zamalka, in an area that was opposition controlled but still close to positions of the Syrian army. Additionally, the terrain matches the features in the purported video of the rocket launch.

Name

Effectinfo icon

Updated Likelihoods

Syrian army
÷3
7%
Opposition
×15
93%

Lack of intelligence reports

Name

Effectinfo icon

Updated Likelihoods

Syrian army
÷2
3.6%
Opposition
-
96%

Western governments have claimed that the intelligence points to the Syrian army. However, no reliable evidence was shared pointing to either side. This lowers the likelihood that the attacks were carried out by the Syrian army, which was monitored more closely than the many different factions of opposition forces.

Name

Effectinfo icon

Updated Likelihoods

Syrian army
÷2
3.6%
Opposition
-
96%

Moadamiyah

Name

Effectinfo icon

Updated Likelihoods

Syrian army
×1
3.6%
Opposition
×1
96%

The same night as the Ghouta attack, there was a reported chemical attack in Moadamiyah, on the other side of Damascus. This would imply a much larger scale of attack, which is more likely for an army attack. However, there is little evidence to support this claim, and it seems mostly based on confusion. Overall, this does not affect the analysis.

Name

Effectinfo icon

Updated Likelihoods

Syrian army
×1
3.6%
Opposition
×1
96%

Discussioninfo icon

userIcon
user icon
JGH
Jun 21, 2021 at 4:10 PM
Hexamine can also be linked to the rebels. Hexamine is typically used (among some other thing), for the production of explosives like RDX, HMDT and others [1] . The "rebels" (or better terrorists) did produce IDEs and "self-build" mortars in large numbers [2]. The chemical laboratory in rebel possessions found in douma 2018 and examined by the OPCW 2018 had hexamine in stock, among other things [3]. The OPCW comes to the conclusion that explosives and the like were produced there in the laboratory [3]. See the OPCW-Douma Report 2018/19, to cite page 67/68 form the Report [3]: "The chemicals identified and which were present in bulk quantities are precursors thatare consistent with the production of explosives and propellants. ... ... Although large quantities of hexamine, ..." Hexamine may can be used as acid stravanger in binary-sarin reacation (DF+IPA), but known and typical is the use of other amines, like isopropylamine. Isopropylamine ist well solvable in IPA an well know for use in binaray sarin weapons [4] -- Hexamin is solid(maybe powder) and unsolvable in IPA and not know for use as acid stravanger in sarin-production or weapons in literature. Hexamin is unlikely to be used as a acid stravanger in "real" highly developed binary sarin-weapon-systems similar in funktion to the US M687 [4]. But syria was know for having stockpiles of highly developed binary sarin-weapon-systems bevor 2013 [5]. My assessment: None of the syrian military binary sarin-weapon-systems ever has used hexamin. Maybe there was some use of hexamin in the first steps of production of chemical weapons in syria. It is different with the rebels. When the rebels got to DF e.g. from Libya, getting IPA (Isopropyl alcohol) is easy -- but getting Isopropylamine is not. I guess rebels used hexamin in some kind of primitive sarin production becource they have ist. I guess some of Libyas DF - stocks find ther way to syrian terrorists in 2013. Ther was plenty of DF in the libyan desert without any guard [6] [7] [8]. References: [1] https://en.wikipedia.org/wiki/Hexamethylenetetramine [2] https://www.theatlantic.com/photo/2013/02/diy-weapons-of-the-syrian-rebels/100461/ [3] https://www.opcw.org/sites/default/files/documents/2019/03/s-1731-2019%28e%29.pdf [4] https://en.wikipedia.org/wiki/M687 [5] https://besacenter.org/wp-content/uploads/2013/09/perspectives214.pdf [6] https://www.telegraph.co.uk/news/worldnews/europe/spain/9735472/Al-Qaeda-may-have-chemical-weapons-Spains-counter-terror-chief-warns.html [7] https://www.nti.org/gsn/article/libyan-weapons-depot-unguarded-open-to-looters/ [8]https://www.spiegel.de/fotostrecke/libyen-waffenlager-im-wuestensand-fotostrecke-74496.html
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Rootclaim
Oct 7, 2021 at 11:01 AM
It’s interesting that large amounts of hexamine were found in opposition stores, but it could have been for the production of explosives, unrelated to the sarin. On the other hand, hexamine was specifically listed in the Syrian army’s chemical weapons program. As we mentioned in the analysis, even if the Syrian army uses hexamine, the opposition could have copied the process from Syrian sources.
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Not_An_Assad_Apologist
Jul 29, 2021 at 7:52 AM
The key part in [3] - "no other sarin precursors were observed." Just because they have hexamine does not mean they can manufacture sarin. Next conspiracy...
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qs
Jun 20, 2021 at 11:37 PM
It seems like this was a freak accident. Liwa al-Islam was making a rather complex rocket artillery strike with poor intelligence (near total darkness) and training and upon discovering what they had done got other FSA members to pin the blame on Assad.
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Rootclaim
Oct 7, 2021 at 11:59 AM
We focus on an intentional attack, but we have not ruled out a mistake. The reason we give more weight to an intentional attack is two fold: Firstly, this was a very large unprecedented attack on civilians using around 10 rockets. It would be more reasonable to consider it a mistake if there were multiple rocket attacks on the Syrian army and only one that fell on civilians. Secondly, The rockets were spread out, displaying a fanning effect that looks like an attempt to cover a large area, which is more in line with a false flag than a mistake.
user icon
IMABITOBBSESSIVE
Feb 6, 2021 at 3:28 PM
user avatar
mike jones
Jun 23, 2021 at 2:28 AM
here's the background. the syrian government are rational actors and have always been so. the syrian army was close to taking that town by conventional means. obama said chemical weapons were a redline that would presumably trigger the complete obliteration of syrian forces. hundreds of syrian citizens were killed, but there is no evidence any jihadists were. why would a rational actor, on the verge of retaking their territory from jihadists, do something unnecessary that is also the one thing that could trigger a condition that would guarantee their defeat and eventual hanging by death squads or the hague after the u.s. intervened massively. suicidal irrationality? now on the othe rside, why would the jahidis (that were armed by u.s. allies with u.s. weapons fighting a war against an avowed u.s. enemy state) when they started losing the and were getting pushed out of syrian territory gas a town they were occupying when the united states said a chmical attack would result in direct intervention? a analogy would be you have a bank that was robbed. you know one of two men did it. one man is about to have his home and business foreclosed on. the other man is a billionaire. and bellingcat is wholly sponsored by the state department to create propaganda for u.s. wars of agression, which is to say all u.s. wars.
user avatar
Naomi Allen ♀️
Jun 18, 2021 at 7:42 PM
Bellingcat's "report" is full of rhetoric and a lot of irrelevant noise. How can it be taken seriously?