Analysis of the Second UN Report

If this is your first time here, I recommend starting from the conclusion page.

This post analyzes the UN's final report on the use of Chemical Weapons in Syria, published on December 12th, 2013.

The report, which covers seven separate attacks, spans 82 pages and contains a mix of evidence collected by the UN, evidence reported by the Syrian government, UN analysis and estimates, and procedural documentation. This post attempts to extract from it new findings, which may be relevant for inferring culpability for the August 21^st attack.

Ghouta, August 21st

Given the multiple omissions and mistakes in the initial report of September 10^th, the final report was widely anticipated to provide more information and clarifications. Particularly interesting issues were (a) whether the wrong trajectories reported would be corrected, (b) any conclusions that could be made from the many chemical by-products found in the scene, and (c) clarifications on the numerous discrepancies in the Moadamiyah site.

In that aspect the final report was a huge disappointment. The writers simply chose to sidestep the issues by stating that the September report “forms an integral part of this final report” and only provided some minor updates to the lab results. This leaves us with two possible explanations:

1. The team had no new information to offer since the September report, despite the large amounts of raw data involved and its short time constraints.
2. The team simply wished to avoid highlighting the many mistakes made in the first report, by pretending the objective of the final report was only to investigate new sites.

Khan Al Assal, March 19th

The fact that a chemical attack occurred was already known, but the report adds two interesting findings:

1. Syrian soldiers were indeed attacked and the site was under Syrian government control at the time. These claims by the Syrian government were not widely accepted prior to the report.
2. The agent was an organophosporous compound. This matches the Russian’s finding of sarin in soil samples, but was also not widely accepted, especially since some eyewitnesses reported a Chlorine smell.

It should be noted that the team did not visit the site to take samples due to security restrictions, so their conclusions were based on numerous interviews, which they felt were strong enough evidence (or as mentioned in the press conference: “the footprints in the society… were so obvious”).

The report does not offer any reliable evidence on the delivery method.

Judging by a map attached to the report, the lethal area seems to be 2 hectares (200x100m), which matches the death toll of 25 people. Based on US DoD models, this translates to 20 kg of sarin used.

Bahariyah, August 22nd

In this event, Syrian Army soldiers were attacked by improvised devices distributing a blue gas with a very bad odour. The symptoms reported by the soldiers are clearly indicative of some irritant and not a nerve agent, and their blood samples were negative for sarin (samples were taken by the hospital on the day of the attack, and by the UN a month later).

Jobar, August 24th

In this event, Syrian Army soldiers were attacked by an IED. The interesting findings:

1. A sample taken by the UN team a month after the attack from one soldier tested positive for sarin exposure.
2. All 4 samples taken on the day of the attack by the hospital were positive. This includes samples from 3 soldiers who tested negative by the UN. This is likely explained by the long time passed.
3. The attack involved at least 4 IEDs of 4 liters each, which is 17.4 kg of sarin.

These findings are ground-breaking, as they show for the first time positive proof of a Syrian Army soldier being attacked by sarin. Combined with the evidence previously collected, it can now be ascertained with high certainty that the Syrian opposition possesses sarin.

Ashrafiya August 25th

In this event, Syrian Army soldiers were attacked by canisters launched by the opposition using catapults. One of them landed near a group of five soldiers and released a foul smelling smoke. They then experienced symptoms consistent with nerve-agent poisoning and were evacuated. The interesting findings:

1. All 5 samples taken by the hospital on the day of the attack were positive for sarin.
2. All 3 samples taken by the UN samples a month later were negative .
3. One sample taken by the UN 5 days after the attack was negative.

Since we have both a government and a UN positive result in Jobar, and a match in the negative results provided by the government in Bahariyah, it is safe to trust the positive samples in this case and attribute the negative samples to the time passed.

However, the last finding raises an obvious question: Why was only one sample taken from the five injured soldiers? The astounding answer is hinted in the report:

"Biomedical sampling was performed on 30 August 2013 on selected patients… Due to technical problems during the sampling, only one blood sample was recovered”. 

The following points may help better understand this statement:

1. The report goes to great lengths to describe the meticulous procedures used by the UN team to protect the integrity and authenticity of samples.
2. The team did not report any procedural failures in the collection of samples from makeshift hospitals in the warzone, but only in this secure military hospital.
3. The UN’s visit to the hospital was reported by the media, but for some reason was not mentioned in the September report - an omission which raised a few eyebrows at the time.

While previously there was some hope that the UN's multiple mistakes were somehow attributable to human error, this mess-up leaves us with the unavoidable distressing conclusion that someone within the UN team has been manipulating evidence. The blunt error in the Zamalka trajectory, the ridiculous analysis of the Moadamiyah “impact site”, and now the loss of blood samples cannot all be honest mistakes, especially when considering all three happen to contribute to the regime-attack theory.

This suspicion must be investigated to ensure this would never happen again. A first good step would be to pressure the UN to expose the full raw data (e.g. the raw GoPro recordings, and quantitative lab results).

Saraqeb 29 April

This case, along with a similar attack two weeks earlier, was extensively analyzed by Brown Moses here, here, and here.

According to the opposition sources quoted in the report a helicopter dropped an improvised weapon built from a cinder block with holes containing grenades whose safety pins were removed. When the block hits the ground and breaks, the levers detach and the grenades detonate. The sources claim the grenades contained tear gas and sarin.

Following the attack 13 victims were evacuated to Turkey, of which a 52 year old woman died, and the rest quickly recovered.

The new findings:

1. Body parts taken from the woman in an autopsy tested positive for sarin exposure.
2. A blood sample taken from the woman had low cholinesterase levels, which is consistent with nerve-agent poisoning, but also other conditions such as a heart attack.

To make this incident even more puzzling, here are a few more details to consider:

1. Turkish doctors previously reported blood samples from all 13 patients tested negative for sarin, while France reported finding sarin in samples from this incident.
2. According to this eyewitness report, other people were affected in the same location as the woman. However, the UN report states no one else exhibited severe symptoms.
3. The grenades allegedly used in the attack are probably tear-gas or smoke grenades.
4. The opposition has acknowledged using these grenades, stating they were seized from Syrian army depots.
5. This was the only case (besides Ghouta) where the government accused the opposition of carrying a false-flag chemical attack (here and here).

So what happened in Saraqeb? The main scenarios to consider are:

1. A government attack using an improvised device containing previously unheard-of sarin grenades. The amounts used were so low that it had lethal effects only when falling in close proximity to a 52 year-old woman, indicating the use of sarin had no military gain.
2. The woman’s body was contaminated with sarin (or IMPA) in the Turkish morgue in an attempt to deceive the UN.
3. The lab results were a false positive.
4. A false-flag by the opposition, as claimed by the government.

None of these scenarios seem very plausible, leaving this incident a complete mystery. If anyone can make sense of it, please share your ideas.

Summary of Evidence

For the sake of clarity, here is the full evidence trail described above that links the opposition to the sarin attacks:

1. In Jobar, a blood sample independently taken by the UN from a soldier tested positive for sarin.
2. In Bahariyah, the only of the four opposition attacks that was not a sarin attack, the samples supplied by the hospital were also negative, indicating the government was not attempting to tamper with evidence.
3. In Ashrafiya, the hospital provided 5 positive blood samples, which were confirmed to be from the attacked soldiers.
4. In Khan Al Assal the UN team was convinced from interviews with the victims and medical personnel that an attack with an ogranophosphorus compound has occurred against soldiers and civilians. This adds to the sarin findings by the Russian investigation team.

Conclusions:

1. The opposition attacked Syrian government soldiers and government-supporting civilians with sarin on three separate occasions.
2. The opposition has access to at least tens of kg of sarin. This significantly increases the plausibility of them being able to obtain the hundreds of kg needed for the Ghouta attack – closing one of the main gaps in our current scenario.
3. Elements within the UN team have likely manipulated evidence in attempt to incriminate the Syrian government.

Review of UN Press Conference

If this is your first time here, I recommend starting from the conclusion page.

Before examining the findings of the full UN report published recently, I thought it would be interesting to review the press conference that accompanied it, which provides some interesting information.

The most interesting findings:

16:00 - While probably not too relevant anymore, Sellstrom makes a very significant statement distancing himself from the "trajectory intersection" theory, saying "The flight paths do not seem to meet as may be indicated in the report", and adds that a range of 2km for the UMLACA is "a fair guess".

9:30 and 17:10 - In these two questions Sellstrom is asked about the sarin's quality, referencing his early statement that hinted at high-quality sarin (which was of course interpreted to imply regime culpability). He seems to avoid the first question (9:30) by addressing only the recent incidents where samples were taken from blood and not from soil. The second question (17:10) is more direct, prompting the interesting and evasive response: “I tried to make some comment on the quality of sarin and I compared it to my experience in Iraq”, which seems like an attempt to downplay the original statement and undo its effect.

41:00 - Probably the most interesting finding. Here the panel is asked whether the munitions reported by Syria to the OPCW were related to those used in Ghouta. The response:

"I could say 'No Comment', but I will give you an answer: Not really, there’s no information that sheds light on what happened in Ghouta”.

To understand the significance of this statement it should be explained that the information provided by Syria to the OPCW is confidential and cannot be shared. Sellstrom therefore cannot answer the question directly, but his response heavily hints that UMLACAs were not reported as a Syrian chemical weapon, which is in line with the analysis that it is a repurposed incendiary rocket. Of course, other explanations are also plausible, such as the government secretly destroying a stockpile of chemical UMLACAs to avoid it being associated with the attack.
Update: This report claims that UMLACAs were indeed not reported to the OPCW, but does not provide direct evidence.

Overall, it is hard to miss the difference in attitude during this press conference compared to the spirit of the interim report. While in September the message was along the lines of "We're not allowed to tell you , but we all know who did it", the team is now much more cautious, clearly stating that the evidence is insufficient to implicate either side (39:00), and there is no "information that will stand in court" (43:30).

Update: This WSJ article about the UN report contains two interesting statements from Sellstrom: 

But Mr. Sellstrom said he believed both sides in the conflict had the "opportunity" and the "capability" to carry out chemical weapons attacks. Mr. Sellstrom had just arrived in Damascus to negotiate a visit to Khan al-Assal when the Aug. 21 attack occurred. He said one of his earliest reactions to the attack was that the Syrian government had to be stupid to pull it off with U.N. inspectors in town.

Did I miss anything? Please share your evidence and analysis and help improve the conclusions.

Hexamine is not the Smoking Gun

If this is your first time here, I recommend starting from the conclusion page.

In his recent analysis, Dan Kaszeta provides some interesting chemical analysis of the recent UN report, and also suggests Hexamine could be the smoking gun of the Ghouta attack, going so far as describing it as "very damning evidence of government culpability".

The reasoning could be summarized as follows:

1. Hexamine was reported by the OPCW as part of the Syrian chemical program. This implies it had a purpose in the program, rather than being used for explosives manufacturing etc.
2. Hexamine can be used to bind the HF generated during the sarin binary process.
3. No one else is known to use Hexamine for this purpose.
4. Hexamine was found in multiple samples taken by the UN in Ghouta (both Zamalka and Moadamiyah).
5. It is unlikely the opposition will choose the same HF binding chemical as the government, implying government culpability.

I believe there is a much more plausible explanation for these findings:

1. As Dan notes, the standard chemical for binding HF in the sarin binary process is isopropylamine. It was used by the US for this purpose, it was declared by the OPCW (in the same report), and it was ordered by Al-Nusra in Turkey. There is no reason to believe Syria decided to replace it with Hexamine.
2. So why was it part of Syria's chemical program? This is easily explained when remembering Syria produced not only sarin, but also mustard gas. Hexamine is a well-known stabilizer for mustard gas, discovered in 1945 and adopted by the US Army's Chemical Warfare Service.
3. Which now requires us to explain the Hexamine findings in the field. These are not surprising given the many uses and high accessibility of Hexamine. Specifically of interest are its uses in explosives (which were used to disperse the sarin) and as heating tablets for camping stoves, which are probably widely used in these neighborhoods under siege.
   This conclusion is further strengthened when considering that (a) Hexamine was reported in several samples that did not contain any indications of sarin, and (b) some samples contained other explosive-related chemicals such as TNT and trinitro triazine.

Update

Dan Kaszeta has referred me to this US Army publication, which states on page II-38 that "a small amount of degradation occurs when stored in steel ton containers for over 50 years". It should be noted this refers to the pure form of mustard gas (HD), which is different than the Levinstein Mustard (H) mentioned in the patent above (70% purity). Dan claims H is an obsolete agent, and since "pure HD is quite stable on its own", Hexamine could not be a mustard gas stabilizer, as previously claimed.

This is an important correction which requires revisiting the analysis.

First, we should confirm that Syria indeed stores HD and not H. There is no direct evidence that this is the case, but given that Iraq's inferior program reached purity levels of 90-95%, it is fair to assume Syria does have HD.

Second, we need to confirm that HD does not require stabilizers. The above US Army publication seems to imply it doesn't, but this one states "The stability of Levinstein mustard which has been purified by various methods is also improved by the addition of 1 per cent hexamine" (p. 42), and this patent discusses methods of stabilizing HD, stating "mustard gas thus purified still corrodes steel containers and the corrosion rate is fairly rapid at temperatures in the range of 110F. to 150F". Additionally, when considering that "pure" HD is actually only 96% pure, it makes sense that while it should degrade slower it might still need some stabilization.

Trying to settle this discrepancy I looked into the sources of the first publication and found the most significant one to be this research, which I could not find in full. However, according to its summary it is based on samples taken from US stockpiles held for 50 years. Obviously, these stocks were intended for long-term storage, which according to the other sources contain stabilizers. 

So apparently, the low degradation findings refer to the actual final product (containing Hexamine), and not the hypothetical chemical. 

While investigating this issue, I also found this interesting quote (here): 

"Regardless of the exact reasons for the instability of Levinstein mustard, the problem is fully recognized and is extremely serious during time of war and national emergency when it becomes necessary to build up a very great strategic reserve of this chemical warfare agent in contemplation of the fact that chemical warfare may, at any time, be resorted to."

This brings up another option: That the Hexamine in Syria's stockpile was intended for emergency production of large amounts of H. Since HD's advantage over H is in storage and not in battlefield use, this is a very plausible scenario.

Finally, Dan's response still fails to explain why Hexamine was found in the sarin-negative samples.

As a more general claim: Hexamine seems to have multiple uses in chemical warfare and multiple reasons to be found in the field samples (see many more here). Correlating the two is impossible before meticulously striking off all the alternative causes.

Conclusion: The Hexamine findings in the impact sites are not indicative of Syrian government culpability as they are not reliably linked to the Hexamine from Syria's chemical stockpiles.

Did I miss anything? Please share your evidence and analysis and help improve the conclusions.

Review of Seymour Hersh's LRB Piece

If this is your first time here, I recommend starting from the conclusion page.

The London Review of Books published today a long piece by Seymour Hersh analyzing the intelligence surrounding the August 21st attack. In this post I'll review the main points raised in the article.

Sensors around chemical weapons sites were not triggered prior to the attack
The article doesn't provide any firm evidence that supports this, but it does provide some circumstantial evidence (when they were triggered in December Obama issued a warning, while no such warning was issued in August), and it's reasonable to assume such an early warning system exists.
Since we already know the sarin was probably not from the government's stockpile, and that the rockets were not standard chemical rockets, this new observation makes perfect sense but does not change the picture significantly. In other words, even if this attack was somehow carried out by the regime, it used non-standard weaponry and should not have triggered the alarm.

The US evidence relating to personnel movements and military orders was cherry picked in hind sight.
This again makes perfect sense. There are probably millions of data points collected every day from Syria, which cannot be analyzed in real time. It's safe to assume that following the attack this data was analyzed in retrospect. The fact that despite this effort, the only evidence presented by the US was very weak and circumstantial, is a strong testimony to cherry-picking. Actually, the fact that nothing incriminating wasn't found in all these sources is strong probabilistic evidence that the regime was not involved. This is analyzed in detail here.

The 330 mm rocket (aka UMLACA) is an improvised munition, implying it is not related to the government.
Here Seymour is of course out of touch with the current research at Brown Moses and WhoGhouta, which clearly indicates that the rocket was developed for the Syrian Army, probably to fit its special needs in short-range urban warfare.
However, this in itself is a weak indication of government involvement, since most of the opposition's heavy weaponry has been looted from Army depots.

The rocket's range is less than 2 km, indicating the NY Times report claiming the attack came from an Army base 9 km away is incorrect.
This was already established here three months ago. However, he does say this range estimate was based on "a thorough study", so unless this refers to the WhoGhouta research, it gives yet more credibility to our range estimate.

US Intelligence estimates the opposition has the capability to acquire and use sarin.
This is in line with our analysis, and while no additional hard evidence is provided, his quotes from intelligence sources seem reliable.

Summary: While Hersh does not provide significant new evidence, his quotes from intelligence sources are in line with many of our findings, and his analysis provides much-needed counterweight to the many erroneous reports in the media.

Response to New Brown Moses Theory

If this is your first time here, I recommend starting from the conclusion page.

In his latest blog post, Brown Moses has updated two key points in his analysis of the August 21st attack:

1. Following the recent UMLACA video, and after consulting with warhead expert Richard Lloyd, he estimates the UMLACA range at 2.5 km, which is consistent with our findings.
   Although Brown Moses has never officially claimed a longer range, his original analysis assumed a range of 6-8 km to army sites (more details here). 
2. He decided to replace his own trajectory analysis (pointing North) with those reported by the UN and Al Jazeera (West to North-West).

These updates are substantial in two aspects:

1. So far the WhoGhouta blog was the only source to claim the 2.5 km range. Having a warhead expert and the leading blogger on Syria issue a similar estimate lends much-needed credibility to this number.
2. This officially refutes the HRW "trajectory intersection" theory (also published in the NY Times), which was probably the main rationale for regime culpability in Western public opinion.

While those of us who know the details, have long ignored this theory, we should remember the mainstream understanding is still heavily based on this kind of discredited evidence. So whether or not Brown Moses' updates indicate opposition culpability (he argues they do not), it is important that HRW and the Times be aware of these developments, and be allowed to correct their reports. If anyone has relevant connections, feel free to use them and let us know their response. Ideally, this would be done by Brown Moses himself.

Just to clarify: Brown Moses has never supported this theory, and based his support of government culpability on his (much more reliable) analysis of the munitions used.

As to the analysis itself, I believe it suffers from two weak points:

Trajectories

Brown Moses decided to replace his own trajectory analysis with those reported by the UN and Al Jazeera, which are both highly unreliable:

1. UN Trajectory - Normally, a UN report would always be the preferable source of information when available, but in this case their error is so obvious and easy to verify that it can't be used. Any theory relying on the UN azimuth must explain why this analysis of impact site 1 is wrong. Such strong evidence cannot be simply ignored.
2. Al Jazeera trajectories - Unlike the UN, Al-Jazeera are not a reliable source for the Syrian conflict. They are owned by the government of Qatar and have shown strong pro-opposition bias. Since they don't provide any evidence on how the azimuths were calculated we cannot use their data.
   An example of their low standards is evident when they claim a 5-10 km range for the UMLACA - a number which they do not explain, we know to be wrong, and seems to have been arbitrarily chosen so it matches army positions.

We have three strong indications of a northern source for the Zamalka attack. There is currently no other reliable evidence to support a different trajectory.

Control of Qaboun

The impression from watching the Qaboun videos is clearly of an area that is not under firm government control. Movements in open areas are done by armored vehicles, with troops mostly operating under cover.

However, an UMLACA launch is a complex operation involving two trucks and multiple people operating in the open. In all UMLACA launches documented so far we see troops comfortably operating around the launcher unprotected. It just doesn't seem to be intended for front-line operation.

More analysis on the status of Qaboun on August 21st is ongoing and will be updated here.

Update: In the comments below Amund Hesbol analyzed news reports from Qaboun to build a map of the front line. It is still work in progress, but seems to indicate the positions suggest by Brown Moses are under rebel control.

Update 2: Charles Wood prepared a map of ranges from the launch location proposed by Brown Moses. It indicates that the farthest impact sites may be beyond UMLACA range. However, it should be noted that except for sites marked UN-1 and UN-2, these were reported to HRW by local activists and were not independently verified.

Update 3: Charles Wood went through numerous videos from this channel, and concluded the following.
"With absolute certainty all Government positions between Fares al Khouri in Jobar and 6th Tishreen South of Qabon were under sustained insurgent attack in the lead-up to August 21 and afterwards. By sustained attack, I include mortaring and sniping from positions overlooking the army base. e.g. sniping"

Last, the new theory doesn't explain why the government chose to use low quality sarin and a low-quality chemical weapon instead of the weapons they acquired and tested over the many years of their chemical program.

Conclusion: While Brown Moses' new theory addresses the UMLACA range problem, it raises other issues which make it an unlikely explanation of the August 21st attack.

Geolocating New UMLACA Video

If this is your first time here, I recommend starting from the conclusion page.

HRI found this video showing another UMLACA launch.

The location seems like a perfect match to Qadam railway station. This image shows the location of the camera and the apparent launch direction - 100 degrees (East). 

The video gives the most accurate evidence so far of the conventional UMLACA's range, being launched here at a distance of 1.9 km (details here).

Following 1.9 km in that azimuth falls between an area marked as "Palestine camp" and the Al Tadamoun neighborhood, both marked here to be under rebel control. Al-Tadamoun is often mentioned as the site of clashes between government and rebel forces.

At 1.9 km and 101.3 degrees there is a large industrial building there, which might have been the target.

Some of you may remember we've already seen an UMLACA launch from Qadam station (this is very likely the larger version of the UMLACA - see discussion in comments):

Overall, an interesting finding, which agrees with our previous estimates. Thanks Mark/HRI!

Update:

Going over all the videos related to the Qadam station indicate it is under government control, and frequently attacked by rebel forces. A major attack occurred on January 27-30th, 2013, which resulted in rebel forces capturing at least part of the station. It is documented in the following videos:

Shows forces carrying the ISIS flag fighting in this area to the south of the station.

More fighting in the same area, and then capturing a few buildings inside the station (probably these).

More fighting inside the station (probably here).

This seems to be deeper inside, not clear where exactly.

This video is said to show regime jet shelling in the exact locations found above.

Update: In a comment below Charles Wood points to another video showing rebels inside the northern part of the station.

This brings up an interesting scenario: We have strong evidence of UMLACAs with incendiary warheads falling in Darayya a few weeks earlier (most likely launched from the nearby Mazzeh airport). Since we already know Qadam station is an UMLACA launch site, it is definitely plausible it too had incendiary UMLACAs and a launcher stationed there during the opposition raid. They could be the ones later repurposed to carry sarin and used on August 21st (as described here).
This is of course mere speculation, but it does provide a plausible example for the "captured UMLACAs" theory.

Response to Dan Kaszeta's Chemical Analysis

If this is your first time here, I recommend starting from the conclusion page.

Brown Moses recently published a detailed response by Dan Kaszeta to this blog’s chemical analysis and estimate of sarin production complexity.

First, thanks for publishing it. The more opinions and evidence we gather, the better our analysis will be.

Summary of Dan's Response

Dan generally agrees that the sarin used in Zamalka was of low quality and lacked stabilizers. However, he believes this is not the result of underground manufacturing, but rather a result of Syria having a chemical program similar to the one Iraq had during the Iraq-Iran war. Specifically:
Sarin's main precursor (Methylphosphonyl difluoride) is produced at low purity and stored without stabilizers. When the need comes, it is mixed with isopropyl to create sarin, poured into the munitions and quickly shipped to the battlefield, before it degrades.

He believes Syria chose this process due to the technical difficulties of producing high purity sarin, which he bases on the following claims:

• "The US and USSR made Sarin in poor to mediocre condition for years before perfecting the process".
• "Iraq devoted a large effort to manufacturing nerve agents and did so in large quantities during the Iran-Iraq war. The size, expense, and scope of the Iraqi industrial program is well documented by UNSCOM and UNMOVIC, and appears to be larger than the Syrian program.  Yet it made an inferior grade of Sarin".

Additionally, he believes the opposition could not have produced the amounts of sarin used in Zamalka (several hundred kg), for the following reasons:

• The last underground attempt to manufacture large amounts of sarin (Aum Shinrikyo) was unsuccessful despite large investments.
• It is a very expensive operation: “The US OTA study estimated that you needed at least $10 million in 1993 USD to get a basic setup going”.
• Using this investment to produce conventional weapons would be much more efficient, or in his words: “Thirty million dollars buys a lot of conventional equipment that is much more immediately useful than a few tons of Sarin”.

All of these claims are incorrect or irrelevant.

Rebuttal of Claims

Claim: The US and USSR took years to reach high purity (implying Syria's product would be of low quality).

Response: Comparing a modern chemical program to ones started over 50 years ago is meaningless. Lab technology is far more advanced and know-how has dissipated. In any case, even back then the US and USSR were able to reach high purity within a few years. Why would the Syrian program not reach this ability after 30 years?

Claim: Iraq’s bigger chemical program never reached high purity (implying Syria's product would be of low quality)

This is a misunderstanding of Iraq’s program. Iraq developed agents to be used immediately in the battlefield. They therefore focused on quantities rather than shelf-life. A few relevant quotes:

“While the purity of nerve agents produced were effective enough for immediate use on the battlefield during the Iran-Iraq war, they were not suitable for long-term storage”.   (Source: UN report on Iraq’s chemical weapons)

"The short shelf life of Iraq's nerve agents was not a problem during the war with Iran, because Iraq's CW manufacturing facilities were able to produce large quantities of agent shortly before it was to be used in battle".   (Source: Declassified CIA report)

“Although the Iraqis could have distilled their sarin to remove the excess HF, they chose not to do so because the batches of agent were intended to be used within a few days”.   (Source:  A U.S. Congress, Office of Technology Assessment report)

"CIA analysts believe that the shelf life problem was only temporary and that the Iraqis can now produce unitary agents of sufficient quality by adding a stabilizer or improving the production process".   (Source: The same CIA report)

Syria, however, has a completely different goal. Their chemical program is intended to counter Israel’s nuclear program. It therefore requires long-term storage and quick deployment of large quantities. A “just in time” mixing operation imposes a significant bottleneck which limits the amount of agent that can be deployed in a short time frame.

Syria would therefore need either a high-purity unitary process (i.e. storage of prepared sarin ready for quick deployment), or have binary weapons that mix the agent in-flight. Recent OPCW reports state Syria’s stockpiles are held in binary form, indicating the latter is more likely.

And indeed, Syria is generally believed to have large stockpiles of operational binary warheads and “a high level of know-how in the chemical weapons technology” (source: French Intelligence Report). As early as 1991 the US estimated that “Syria has an advanced CW program. The program has concentrated on developing sarin in two binary-type munitions: 500-kg aerial bombs and Scud B missile warheads” (source).

The only reason one would be forced to assume that Syria’s program is based on this non-standard “just in time” binary process is to justify why the rockets used in Zamalka don’t have binary warheads (evident by the rockets not having slanted fins or multiple nozzles, which are required to spin the rocket and mix the agents in-flight). When accepting that Zamalka was an opposition attack, these unlikely assumptions are no longer needed.

Last, the claim that Iraq’s program was bigger than Syria’s is not backed by evidence. Syria’s program is active for over 30 years with access to current technology, while Iraq was a 10 year program that ended 20 years ago.

Claim: The last underground attempt to manufacture large amounts of sarin (Aum Shinrikyo) was unsuccessful despite large investments.
Aum Shinrikyo indeed developed only around 100 kg of sarin in a year and half, while the Zamalka attack required several 100 kg’s. However, the Syrian opposition has several advantages over Aum Shinrikyo:

1. Much weaker government supervision. Treating the opposition as a non-state actor would be inaccurate, as they have full control of some areas of Syria, making them the de-facto state there. This is critical: Aum Shinrikyo had stopped their process several times and destroyed products because of police investigations. 
2. Possible access to former Chemical Warfare professionals from Iraq, Libya or Syria.
3. Access to lab technology that is 18 years more advanced. This was specifically addressed in this detailed analysis of Aum’s chemical program, which estimated that current lab equipment would make a similar effort much cheaper. Quotes:
   “Such an effort might be well disguised or established on a smaller scale, however, by taking advantage of the development over the last decade of powerful, low-cost micro-production chemical capabilities”.
   “… the chemical industry has, over the last decade, introduced modular and flexible designs where reactions may occur in a solvent-free environment, at increased concentrations and in much smaller and less expensive facilities”.
4. International allies. This could prove very helpful when trying to obtain regulated chemicals or lab equipment.
5. Internet access, which makes information on sarin production widely available (e.g. details of Aum Shinrikyo’s process). This can significantly accelerate production - Aum Shinrikyo scientists spent much of their time in trial and error.

Furthermore, Aum’s big investment was in a plant intended to produce 2 tons per day. The opposition does not need such a large plant to carry out the attacks documented so far.

Claim: "The US OTA study estimated that you needed at least $10 million in 1993 USD to get a basic setup going"

This quote was taken out of context, without providing a link to the source (source here). The full quote is:

"Arsenal for substantial military capability (hundreds of tons of agent) likely to cost tens of millions of dollars”. 

This capacity is 100 times larger than what the opposition requires, and assumes military-grade quality, which wasn’t the case in Zamalka.

Additionally, this estimate is not only in “1993 USD”, but also in 1993 technology. As described above, lab technology has advanced significantly since then.

Last, it is very possible that the opposition’s plant was not built from scratch but was rather based on a captured chemical plant. Significant work would still need to be done to convert the plant to produce sarin, but it would be much easier and cheaper than building a new one. We know of at least one captured plant.

It’s hard to give an accurate estimate, but when considering all the factors above, it won’t be surprising to find that the whole operation cost less than $1 Million.

Claim: Using this investment to produce conventional weapons would be much more efficient, or in his words: “Thirty million dollars buys a lot of conventional equipment that is much more immediately useful than a few tons of Sarin.”

Besides the cost estimate being greatly exaggerated, this analysis assumes the weapons were intended to be used exclusively against regime forces. When considering the US red line, the value of a well-executed false flag attack becomes obvious: The US could win the conflict for the opposition within weeks, like it did in Libya. This would make a sarin plant the best investment possible.

Additional Evidence

Besides none of the claims holding up to scrutiny, the theory fails to explain why the opposition has been ordering large quantities of chemicals only relevant to sarin production. Were they risking arrest and spending money without having a laboratory that can process them?

Probably the most important aspect that Dan doesn’t address at all is the specific nature of impurities found in Zamalka. These can give us important insights into the production process. Most notable are the following two findings:

1. Ethyl isopropyl methylphosphonate is the most common by-product reported by the UN. It is very telling, because the sarin production process introduces only chemicals with methyl groups. Ethyl groups should not be present in the final product at all.
   This indicates that one of the alcohols used (Methanol in stage 2 and/or Isopropanol in stage 6, see appendix) was in itself impure and contained ethanol. This level of contamination occurs in very low grades of chemicals, and is a strong indication of underground production.
   A military operation would not have any problem getting access to high-purity alcohols and paying the modest difference in price.
   Update: Charles Wood pointed to this OPCW report which indicates Syria's chemical weapon sites contained stocks of Isopropanol. This removes the remote possibility that they had to obtain Isopropanol elsewhere to produce sarin, and reduces the likelihood that government-produced sarin would contain Ethyl groups.
2. Hexafluorophosphate was also found by the UN. It could have come from two places:
   (a) Residual phosphorus trichloride in step 2, which reacts with thionyl chloride in step 4 to produce Phosphorus pentachloride, and then reacts with Hydrogen Fluoride in step 5 (see appendix).
   (b) A by-product of step 1 intended to produce Phosphorus trichloride, but also producing Phosphorus pentachloride, which later reacts with Hydrogen Fluoride in step 5 (see appendix).
   This indicates that the sarin used in Zamalka was produced starting at step 1 or 2 (which is also consistent with the chemicals ordered in Turkey). A Military operation would have no reason to start with such basic chemicals, and could easily acquire large quantities of Dimethyl methylphosphonate of high purity, a common agent in the chemical industry, thus skipping directly to step 4.

Summary

So the scenario proposed by Mr. Kaszeta requires us to believe that:

1. Despite 30 years of development, and in contradiction to intelligence estimates that Syria has binary warheads, they chose to use a “just in time” binary process for its CW program – A process that would make the program an ineffective deterrent against Israel’s WMD program.
2. They chose to develop sarin from basic chemicals and use cheap low-grade alcohols, for no apparent reason, damaging product efficiency and shelf-life.
3. They chose to use a lower-quality locally developed rocket that requires them to go into rebel-held territory, instead of deploying one of the many advanced delivery devices in their disposal.
4. The opposition has been ordering chemicals that can only be used to produce sarin, without having the equipment to process them.

On the other hand, the alternative explanation only requires us to assume that one opposition faction decided to try to meet the US red line and potentially win the war, by making a modest investment.

Analysis of Amount of Sarin used

I will also take this opportunity to respond to another report by Dan Kaszeta, which raised doubts as to whether the number of rockets used in the attack is sufficient to cause the number of casualties reported. The calculations are based on several incorrect assumptions, but most importantly it uses data tables that assume an attack on prepared troops who wear gas masks within 15 seconds ("Based on... 15 second masking time"). This was obviously not the case in Zamalka, where sarin was inhaled by victims for a 50-100 times longer period. The longer exposure time is more than enough to account for the gap in Dan's report, making 5-12 rockets of 60 kg sarin a sufficient explanation for the number of casualties reported.

Some Thoughts

This section contained an off-topic discussion of the public debate. Now that it is no longer being discussed, I removed it.

Appendix - Sarin Production Process

This is a process that starts with the most basic chemicals. It was found to be consistent with the chemicals ordered in Turkey, and the by-products found by the UN. In an advanced program, the first steps could be skipped by starting with more complex chemicals.

1. White Phosphorus + Chlorine = Phosphorus Trichloride
2. Phosphorus Trichloride + Methanol = Trimethyl Phosphite
3. Trimethyl Phosphite + Halo-Methane = Dimethyl Methylphosphonate
4. Dimethyl Methylphosphonate + Thionyl Chloride = Methylphosphonic Dichloride
5. Methylphosphonic Dichloride + Potassium Fluoride or Hydrogen Fluoride or Sodium Fluoride = Methylphosphonyl Difluoride
6. Methylphosphonyl Difluoride + Isopropanol / Isopropyl alcohol (+ Isopropylamine to neutralize Hydrogen Fluoride)  = sarin

Diagram copied from this analysis of Aum Shinrikyo's process (starting from step 2 above):

Thanks to DDTea for his contributions in analyzing the UN’s chemical report.