The evening of 20 August 2013 was warm. As the night wore on into the early hours of the 21st the air was cooling. A lowering nighttime temperature provided the ideal atmospheric conditions for a chemical weapons attack, as the air was not being heated from the ground-up (and thus, rising), but rather was cooling from above (driving the air downward). This meant that the air pushed the dispersed chemical agent downward; into basements and cellars, places where people would take shelter from bombings. Cooler air also holds gas near the ground, making escape next to impossible.

Courtesy Wunderground.com

Exactly one year prior, on 21 August 2012, American President Barack Obama gave a press conference concerning the escalating violence in Syria. His stance was unmistakable: “We have been very clear to the Assad regime — but also to other players on the ground — that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized. That would change my calculus; that would change my equation”.

With Eastern Ghouta lying near the strategic Mezzah Air Base and the Air Force Intelligence barracks, and as opposition forces took more territory near Damascus, the Assad regime needed a way to rapidly push back at opposition forces. Chemical weapons had been used in the Syrian war prior to the attack on 21 August 2013, but these attacks typically utilised chlorine gas, save for a few incidents (including the Khan al-Asal attack). But by August of 2013, the Assad regime was in retreat, and desperate to stem the tide of its losses.

Eight to twelve modified 122mm Grad-style rockets, which were most likely fired from regime-held territory, landed in Eastern Ghouta. The rockets exploded with a small explosive charge, dispersing their contents in a fine mist. The effect on human and animal life in the impacted zone was immediate, and in the language of the United Nations investigation into the attack (A/67/997–S/2013/553):

“Survivors reported an attack with shelling, followed by the onset of a common range of symptoms, including shortness of breath, disorientation, rhinorrhea (runny nose), eye irritation, blurred vision, nausea, vomiting, general weakness, and eventual loss of consciousness. Those who went to assist other community members described seeing a large number of individuals lying on the ground, many of whom were deceased or unconscious. These individuals reported observing labored breathing and excessive salivation among a large proportion of the survivors. Several of these “first responders” also became ill, with one describing the onset of blurred vision, generalized weakness, shaking, a sensation of impending doom, followed by fainting.”

Immediately after the chemical attack, the Assad regime’s Syrian Arab Army (SAA) and allies launched an offensive into Eastern Ghouta, along with a sustained artillery and airstrike campaign designed to cover up evidence of a chemical attack. Additionally, large fires were lit, which caused the air in the impacted area to be drawn up into the atmosphere and thus further remove evidence of a chemical attack.

OPCW investigators in Eastern Ghouta

While around 4,000 people began displaying symptoms of sarin exposure, videos circulated online of the attack and shocked the world. The United Nations Security Council (UNSC) met in an emergency session. A resolution was drafted calling for an immediate investigation into the attack. At the insistence of Russia, however, the wording of strongly worded draft resolution was watered down to meekly say that the Council was “seeking clarity” on the attacks. Investigators were also not granted the ability to name the party responsible for the attack, once more due to Russia and China threatening with a veto.

Five days later, when experts finally arrived in Eastern Ghouta, much of the evidence had been erased and/or compromised although investigators were still able to discern that sarin had been used, carried by surface-to-surface rockets. This was able to be determined through examining samples of soil,debris (including with rocket fragments) and medical samples from patients at local hospitals.

The Syrian government has never admitted to losing any stockpiles of chemical weapons, nor did they admit to losing control of large quantities of sarin precursor chemicals. In fact, prior to their declaration to the OPCW Fact-Finding Mission in 2013 following the East Ghouta attack, the Syrian government had refused to admit they even possessed chemical weapons. The first instance of sarin use in the Syrian war, an incident at Khan al-Asal near Aleppo on 19 March 2013, was also investigated by the United Nations team. While they were unable to visit the site, they were able to collect samples from various authorities (including the Syrian government) that proved sarin had been used.

OPCW/UN Mission to East Ghouta Sample Results

The UN collected samples in Eastern Ghouta starting on 26 August 2013. Analysis showed sarin contamination, as well as traces of hexamine. According to chemical weapons expert Dan Kaszeta, hexamine had no real history in chemical weapons use prior to the Syrian conflict, but it can be used in sarin for the purpose of neutralizing or reducing the impact of acid buildup. Binary sarin is produced by combining two non-weapon chemicals to form a chemical weapon. In this difficult synthesis process, which tends to be done only in highly-controlled environments, large quantities of acidic byproduct is created, presenting a corrosion problem for metal containers and canisters.

In the US chemical weapons program, isopropylamine was often added to reduce the impact (called “acid scavenging”) of the acid byproduct. In the case of Syria’s state-run chemical weapons program, it is suspected that hexamine was used for this purpose instead. This is corroborated by the very large (80 metric tons) stockpile of hexamine disclosed to the Organization for the Prohibition of Chemical Weapons (OPCW) in 2013.

Thus, the relative high amounts of hexamine found at the site of the attack strongly implies that hexamine was used in the chemical agent itself, and that the sarin in question was produced in a lab with access to large quantities of hexamine. And without an advanced industrial base and the means to import large quantities of industrial chemicals, there is no conceivable way in which the Syrian opposition, barring access to Assad regime inventories, utilized sarin (containing large amounts of hexamine) against their own people in Eastern Ghouta.

Further evidence for regime culpability in the Eastern Ghouta attack can be drawn from other similar attacks throughout the conflict. Another well-known attack is the 4 April 2017 sarin attack in the town of Khan Shaykhun. That attack, investigated by a different body aligned with the UN, the OPCW, did have the authority to declare guilt in the use of sarin. While the investigation was halted via a Russian veto at the UNSC, the investigators were able to gather enough information to come to the following conclusions:

“The sarin identified in the samples taken from Khan Shaykhun was found to have most likely been made with a precursor (DF) from the original stockpile of the Syrian Arab Republic… On the basis of the foregoing, the Leadership Panel is confident that the Syrian Arab Republic is responsible for the release of sarin at Khan Shaykhun on 4 April 2017.”

Sarin is not the only toxin used by the Assad regime;the Syrian government has utilized chlorine on numerous occasions as a weapon against its own people. The UN has also commented on the use of chlorine in Syria:

“However, sufficient facts were collected to conclude that incidents in the Syrian Arab Republic likely involved the use of one or more toxic chemicals— probably containing the element chlorine—as a weapon.” [LINK]



“There is sufficient information for the Panel to conclude that the incident at impact location No. 2 was caused by a Syrian Arab Armed Forces helicopter dropping a device that hit the house and was followed by the release of a toxic substance, matching the characteristics of chlorine, that was fatal to all six occupants. The remnants of the device are consistent with the construction of a barrel bomb.” [LINK]



“The Leadership Panel also determined, in the third report and in section III above, that the Syrian Arab Armed Forces had been involved in the use of toxic chemicals as weapons in three cases: Talmenes (21 April 2014), Qmenas (16 March 2015) and Sarmin (16 March 2015). Their helicopters were used to drop barrel bombs in those three cases.”[LINK]

Thus, there is no real question as to who is responsible for the use of chemical weapons on a wide scale in Syria. Further, much of the information in the UN reports can be discerned by the general public by looking through the Syrian Archive’s chemical weapons violation database. Without the infrastructure required to produce sarin, and without access to large quantities of industrial chemicals, the Syrian opposition was simply not in a position to manufacture or utilize sarin gas in August of 2013. As has been mentioned above, not only has the United Nations declared that the sarin used on 21 August 2013 was from Syrian government stockpiles, but they have even named the government as the guilty party for the 4 April 2017 attack.