Fourth Chemical Volcano Rocket Used On August 21st Geolocated

Following on from yesterday's post on a third possible impact location of the chemical rockets used on August 21st I've been investigating more of the GPS co-ordinates provided to me by the local who filmed the video used in this ITN report

I now believe there is enough information to locate the position of the rocket I've dubbed Volcano 4 (playlist here).  One set of GPS co-ordinates pointed to this location


After reviewing video footage collected for the 8-9 Volcano rockets recorded after the attack, I believe this is almost certainly the location of Volcano 4.  The below clip shows a view to the west followed by a view to the east from two different videos.

Firstly, the location itself.  We can see to the north there's a brick wall which appears to have been pierced by the rocket, and in this image from Google Earth's historical satellite imagery we can see it's casting a shadow

In the satellite imagery it appears the building just west of the wall, on the north side, juts out to the south

In the video we can actually see it's only the top floor that juts out, while the ground floor is level with the wall

It's also noticeable that the building to the south is not parallel to the street, which can be seen on the satellite map

In the view east, we have a clear shot down the road

Satellite imagery shows a large multistorey building to the east, as visible in the above still

Although somewhat obscured in the video by greenery, the historical satellite imagery appears to show that the design of the building matches what we see in the video

Combined with the GPS data, I think this proves a strong match to Volcano 4.  What's also very interesting about this video is it appears the munition passed through the wall to the north, landing just south-east of the hole in the wall.

It's worth keeping in mind that just northwest of this position is a building that appears to be at least two storeys tall, so it's possible the munition could have deflected off the building.  However, it does seem likely the rocket would have come from the northwest.  I've created the following map showing the distance from the impact site, with the red line being 2km, yellow being 2.25km, and green being 2.5km.

It's worth noting the area south of the motorway running from the north to the west of the picture was the scene of Operaton al-Kabune, a government operation to secure a strip of land between Jobar and Qaboun, with the aim to encircle Jobar and Qaboun along the motorway running north to south in the above image.  That operation commenced on August 20th 2013 as part of Operation Capital Shield.

A big thank you to Chris Kabusk for help finding the impact locations of this rocket.

Responses To The Final UN Report Into The Use Of Chemical Weapons In Syria - Part 3

In part three of my review of the final UN report into the use of chemical weapons in Syria, Dan Kaszeta of Strongpoint Security takes a look at the chemical evidence in the report, and details what could be some key evidence.

Fluoride reactivation / regeneration techniques

Many observers, myself included, were worried about whether too much time had elapsed between exposure of alleged victims and the collection of biomedical samples.  I was also discouraged by the fact that the UN’s earlier report did not go into any great detail on the technical methods used for analysis of the samples.  Much of the technical discussion at the time involved techniques that were used in the aftermath of the 1994 and 1995 Japanese incidents, which have shortcomings. Acetylcholinesterase counting is non-specific and can’t tie the sample to an exact causative agent.  Measurement of direct Sarin, IMPA and MPA levels is rather time limited, due to hydrolysis of Sarin and the body’s gradual elimination of IMPA and MPA.  With regard to the incidents in Syria, the time elapsed between alleged exposure and the collection of biomedical samples meant that, at best, these older techniques would have been at the outside edge of their usefulness, if not useless entirely.

The final UN report provides some additional details about the technical methodology that I find reassuring.  Plasma and whole blood samples were prepared for definitive analysis by using a technique known variously as fluoride regeneration or fluoride reactivation. Fluoride reactivation is a technique has been explored since at least the early 2000s.  This technique obviates some of the deficiencies of older procedures.  Sarin not only reacts with the water in the blood plasma through hydrolysis (forming so-called ‘free metabolites’), but also reacts with various proteins to form ‘protein adducts’.  These protein adducts are not so easily removed from the body, and remain for a longer period of time than the free metabolites.  One clear advantage of this process is that the period, post-exposure, for determination of Sarin exposure is much longer, possibly 5 to 8 weeks according to at least one study. (Polhuijs M. et. al)

The fluoride reactivation process adds fluoride (often by use of a sodium fluoride solution) to the protein adducts to re-create the original Sarin, which can be measured by a number of conventional techniques.  As there are no other reasons why Sarin would be generated by fluoridation of protein adducts in a given blood sample, this technique is a very good indication that the person had been exposed to Sarin.  Also, as the fluoride reactivation specifically creates Sarin molecules, this technique discriminates between the various organophosphates.  In other words, this technique has good specificity –  it rules out exposure to other nerve agents or organophosphate pesticides as the causative agent.  Based on my review of the available literature and discussion with several scientists in this area, I believe that this technique is the best available for this sort of analysis.  I have no reasons to doubt the test results.

A more lengthy technical explanation of some of the earlier work in this area from 2003 and 2004 is contained in an article by E.M. Jakubowski, et. al., which is available online here.

Detection technologies used in laboratory analysis

The combination of gas chromatography and mass spectrometry is widely considered as highly definitive for identification of specific chemical compounds.  Numerous variants of this technique are routinely used around the world for chemical identification. The final report shows the following techniques were used by the OPCW laboratories:

• Gas chromatography–High resolution mass spectrometry 
• Gas chromatography–Tandem mass spectrometry
• Liquid chromatography–Tandem mass spectrometry
• Gas chromatography–Flame photometric detection

This list of techniques is consistent with my expectations.  As long as proper procedures were used, these methods are more than adequate for the chemical identification task.

Analysis of Appendix 5 of the Final Report

The final report, as expected, provides a greater amount  of information about the environmental samples collected at Moadamiyah and Zamalka.   There are numerous small differences between the original interim report’s Appendix 7 and the new Appendix 5.  I will summarize the differences I have discovered:

1. Appendix 5 (i.e. the new report) contains more detailed descriptions of the how and what was sampled.
2. Diisopropyl Methylphosphonate (DIMP) has been recategorized from “degradation and/or byproducts” to “other interesting chemicals.”  There’s no explanation for this re-categorization.  
3. Several of the detections of actual Sarin (GB) are further annotated to indicate either trace or high concentrations.  These terms are not defined.  Only laboratory 2 makes this distinction. 
4. There are some instances of minor discrepancies between the earlier report and the final report. In sample 1, lab 1 shows hexamine, where none was shown in the earlier report.  There can be many reasons why this is the case, including reexamination of samples after the interim report was issued, but that is only speculation.  As a general summary, more chemicals are shown in the final report. 

Specific examples in Appendix 5 that I feel are revelatory:

Sample 25.  The fact that a “high concentration” was found on this metal bolt, combined with paint and rust, is exactly where I would suspect the highest concentration to be found in the remnants of a weapon system.  Experience, not widely published or circulated, from both Iraq and the US chemical demilitarization effort have indicated that screw threads can trap nerve agents for a long time and that paints and coatings can trap Sarin between the paint and the metal, greatly increasing its persistence. 

Sample 28.  The rubber window gasket is another place where a high concentration of Sarin was found. Many rubber and plastic substances can be quite good at absorbing Sarin liquid and vapor, and only slowly desorbing the agent. 

I think that these two samples are very important.  Of all the samples, these would be the two where I would expect the highest concentration to be.  But that assessment is only based on many years of work in this field. I also think that someone deliberately planting evidence to fake this incident is not likely to have known what I know about field behavior of Sarin.  Very few people would have known to put the Sarin on the screw threads if it wasn’t there already from leakage from the munition.  Likewise, who would have put it into the window gasket? 

Hexamine may be the smoking gun

Hexamine was discovered in a wide variety of the environmental samples.  Hexamine also appears in the declared inventory of significant chemicals reported by the OPCW after disclosure and inspections subsequent to Syria’s accession to the Chemical Weapons Convention. It would have been informative if the UN and OPCW had explained why they considered hexamethylenetetramine (‘hexamine’) to be considered as a chemical of significance to this investigation.  I do not think that hexamine’s normal uses as a heating fuel and component of some conventional explosives do not merit its inclusion as a chemical of concern by the OPCW, nor would it merit inclusion in the declared stockpile (here) that needs to be destroyed.

However, based on numerous sources of information I have deduced the chemical warfare significance of hexamine, both in the numerous environmental samples and in the declared chemical inventory.  Hexamine is apparently being used by the Syrian government as an additive to binary Sarin.  The inspections subsequent to the UN/OPCW investigation covered by this report reveal that the Syrian concept of operations was to employ binary chemical weapons. (here)

Binary Sarin weapon systems combine methylphosphonic difluoride, also known as DF, with isopropyl alcohol to form Sarin.  The resulting mixture has a lot of residual acid in it, in the form of hydrogen fluoride (HF), which is highly destructive, possibly to the point of ruining the weapon system.  The US Army’s cold war era Sarin program used isopropylamine to reduce this excess HF.  Several chemists and engineers knowledgeable in the matter have confirmed to me that hexamine is useful as a Sarin additive for the same reason.  One hexamine molecule can bind to as many as four HF molecules. This would explain the declared Syrian stockpile of 80 tons of hexamine.  Interestingly, the same stockpile contains 40 tons of isopropylamine as well.   

I consider the presence of hexamine both in the field samples and in the official stockpile of the Syrian government to be very damning evidence of government culpability in the Ghouta attacks.  7 weeks of research on this subject reveal no public domain evidence of hexamine being used in this way in other Sarin programs.   The likelihood of both a Syrian government research and development program AND a non-state actor both coming up with the same innovation seems negligible to me.  It seems improbable that some other actor wanting to plant evidence would know to freely spread hexamine around the target areas.  

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More responses to the UN report can be found in part 1 and part 2 of this series.

Syria CW Stockpile on the Move – Russian Help?

A guest post by Olly Morton and Hamish de Bretton-Gordon of SecureBio.

Introduction

The Syria Chemical Weapons (CW) saga in 2013 has bought weapons of mass destruction to the forefront of the world’s media however, the threat is no longer constrained to just Syria and its neighbours.  As the OPCW and UN begin to oversee the movement of Syria’s CW stockpile out of Syria and destruction on the high seas, proliferation is the major threat to this process and perhaps the Geneva 2 peace talks 22 Jan 14.  Russia has come in at the last minute and though this option may be viable will certainly delay things beyond Geneva 2.  The international Community is currently being held hostage by Syria’s CW.  With the growing threat of extremist organisations drawn to the conflict and the porous land borders has dramatically increased the risk of chemical, biological and radiological proliferation by non-state actors.  At the same moment 6400 barrels of radioactive Yellow Cake is discovered unguarded in the deserts of Libya which could be used as part of a Radiological Dispersion Device (RDD), Cobalt 60 is stolen in Mexico, but it looks like Iran will be hindered in its bid to weaponise its enriched Uranium and Plutonium.  Proliferation poses a significant threat to regional stability and increases the threat of a “spectacular” terrorist attack against the western world and never before has the terrorist use of WMD been more likely. 

Figure 1 - Prominent Syrian CBR production facilities

Ambitious Beginnings

Unlike Iraq, Syria sought to develop an offensive chemical weapons (CW) capability from the outset; the programme began in 1971, fuelled by growing concerns about regional stability and the immediate threat posed by Israel.  Initial development and implementation was supported by Egypt however, with the signing of an agreement with the Soviet Union and the development of the Tartus naval base, expertise from the USSR was provided and Syria began a programme of CW self-sufficiency.  

In addition to its chemical weapons programme, Syria also developed an extensive biological and pharmaceutical programme however, unlike the CW programme, there is little evidence to support its use as a stand-alone offensive capability but the possibility of dual-use is extremely high.  Prior to the civil war, Syria had one of the largest pharmaceutical industries in the region, with a number of the research and production facilities capable of rapidly converting from pharmaceutical research and manufacturing, in particular vaccine work, to producing biological warfare agents; these facilities are known as dual-use.

Prior to the development of its chemical weapons programme, Syria had signed the nuclear non-proliferation treaty in 1968 and went on to ratify it in 1969, enabling them to pursue peaceful civil nuclear power.  By the mid-1980’s Syria had engaged with Argentina, China and Russia in the search for nuclear technologies and expertise, construction began in 1991 on the Chinese Der Al-Hadjar reactor, which became operational in 1996 however, despite the peaceful persona, in 2007 Israel bombed another reactor at Al-Kibar.  Al-Kibar was assessed, by the CIA, to be a plutonium production reactor; the facility was developed in secrecy and had been strictly off limits to international nuclear inspectors, consequently very little was known about it.  Following the 2007 air strike and a series of worrying discoveries by the International Atomic Energy Agency (IAEA), relationships began to breakdown and in June 2011 the IAEA passed a resolution that found Syria to be non-compliant with the nuclear Safeguards Agreement – this has all gone quite at the moment but no doubt with IAEA focus on Iran, the next stage of Syria WMD verification will no doubt look at this programme.

Civil War

In the past 12 months, UK Government has estimated that there have been approximately 14 chemical attacks, supported by positive sample analysis from at least 3 of these attack locations.  Of concern, is that these repeated attacks do not follow a standard modus-operandi but utilise a variety of delivery means, agents and target locations, with the most horrific attack occurring on 21 Aug 2013 in the Damascus suburb of Al Ghouta.    Due to the variety and nature of the attacks, attributing blame and conducting accurate threat assessments is challenging until Al Ghouta. 

Figure 2 - Chemical attacks since Dec 2012

This number of attacks and the scale of the atrocity on 21 August has led to increased media coverage, which coupled with the break down of security, policing and border controls has fuelled international speculation and concern about the threat of CBRN proliferation from Syria.

The base at Safira has changed hands on numerous occasions, but what remains unclear is where the stockpiled chemical weapons and their precursors are?

Proliferation

For historical security and internal stability reasons the regime dispersed its CBRN programmes across the country, ensuring that research, production, storage and delivery means remained separated.  The on-going civil war has caused a breakdown of physical security at a number of CBRN production, storage and research facilities and Syria’s growing extremist threat (both regime and opposition aligned), has enabled non-state actors to have access to Syrian WMD, their associated toxic pre-cursor chemicals and other toxic industrial materials.  Recently even the more moderate opposition activists, view the possession of CBRN weapons as critical to the long-term survival of Syria and the perceived threat posed by Israel.

Open source reporting has suggested that many chemical weapons, precursors and CBRN hazards have already left the country, utilising the worrying combination of porous borders and lack of security; additional reporting has indicated a growing confidence to attack manned government controlled border posts. 

Of significance has been two high prolife arrests made in May and June of this year, the first was the capture of Al Nusrah members in Turkey, on 31 May 13, who were found to be in possession of 2kgs of Sarin.  The second set of arrests were made in Iraq, resulting in the capture of an Al Qaeda (AQ) cell in Baghdad, who were found to be in possession of Sarin pre-cursor chemicals and a complex plan of attack using remote controlled aircraft. 

More recently, a Lebanese paper (Al-Mustaqbal) reported that 20 trucks, carrying CW manufacturing equipment and materials, crossed into Iraq.  Where did they go?  There are many who believe that the Regime has not declared all their CW to the OPCW and that not all of Assad’s CW are currently being centralised and moved to Latakia for disposal.

Syria CW Movement & Destruction – Proliferation

However, the greatest ‘opportunity for proliferation is going to come over the next 3 weeks when Syria’s CW stockpile is moved to the Port of Latakia.  This is about a 300Km journey through at least 2 Opposition held areas.  Military planning yardsticks would suggest this journey if planned and executed by, say by a NATO force or Russian (if available immediately), would expect to take around 3 weeks.  Therefore, to arrive at Latakia in time to be loaded onto a Danish ship and be out of Syria by 31 Dec 13, this operation must start TODAY.  SecureBio have already written on the dynamics of this operation here.  Probably the biggest threat to the convoy will be powerful roadside bombs, which can be big enough to blow 60 tonnes tanks several metres in the air.  A powerful explosion like this would undoubtedly destroy all the mustard gas in the targeted vehicle but the confusion, mayhem and slaughter would undoubtedly provide the opportunity to take some of the other trucks carrying CW material.  This element is covered in more detail on Syria Deeply.  The regime’s request last week for military capability to protect this convoy is either a delaying tactic or they know it is going to fail and are looking for reasons to justify this failure.

Once the CW is on the ‘High Seas’ the Danish vessel which has collected them will have to steam around the Mediterranean until at least the end of Jan 14 when the MV Cape Ray turns up to destroy the 30 tonnes of Mustard Gas and 600 tonnes of Priority One toxic precursor chemicals.  There is a suggestion that this transfer of CW make take place at sea which could be a highly risk operation and the thought of 30 tonnes of mustard gas being lost in the Eastern Mediterranean is probably something which can ‘not’ be allowed to happen.

Mitigation

The size of the Syrian border, its porous nature, lack of security and willingness for activists to challenge border security (where it exists) presents a significant risk to regional stability and potentially even global travel through the proliferation of CBRN agents from Syrian facilities.  

Many of the CBRN agents appear benign and are readily transportable in sealed containers; Sarin is a clear liquid marginally thicker than water.   The benign appearance, combined with current security screening at international borders, which have been developed to counter the trafficking of narcotics, explosives and radioactive isotopes, facilitates the transportation of small amounts of chemical and biological with relative ease.  Due to this security black hole, once chemical biological warfare (CBW) agents have been proliferated out of Syria, their onward movement is all but impossible to track and interdict.

The associated difficulties of identifying, tracking and interdicting these CBW agents, once proliferated from Syria, makes mitigation within current security regimes extremely challenging. 

The OPCW receives the Nobel Peace Prize on Tues 10 Dec 13, let’s hope this is not tarnished by what happens in the next 3 weeks and 6 months, and the previous 16 years of outstanding service keep the Chemical Warfare Convention ‘Flame Alive’. 

The Russians have come in at the last minute to potentially offer protection to the convoy, this is a big call given their experiences in Afghanistan and the Chechnya.  But probably the only viable option at the moment.

Industrial And Economic Aspects Of Sarin : Why Poor Quality Is Not An Indicator Of Non-state Manufacture

A guest post by Dan Kaszeta.

Introduction: 

To use Sarin in any reasonable quantity, an industrial operation is needed.  The Syrian incident in August of this year is of a size and scale that a large production effort was needed to accomplish it.  But even a large-scale effort can produce an inferior quality product.  The alleged poor quality of the Sarin used in Ghouta should not be taken as evidence that the Syrian government did not make it. 

A number of blogs and articles have been advancing, either explicitly or implicitly, a thesis that I would term the “Sarin Quality argument.”  Roughly stated, the argument goes as follows: “The Sarin used in Damascus was obviously low quality.  Therefore it must not have been made by a national level production program.”  The implication, therefore, is that the Sarin in use on 21 August 2013 must not have been made by the Assad regime.   The purpose of this paper is to refute that argument. First, I will make a few general observations.   Second, I will address in detail several points made by various bloggers and activists that are advanced in support of the “Quality” argument.  Third, I will advance my own argument, which I would describe as a “Sarin Quantity and Economics Argument”.

General Observations on Sarin Production and Quality Control

Production of Sarin is actually very difficult, particularly if you want to get more than a few spoonfuls.   Various commentators have commented on the chemistry of Sarin production, but merely listing the chemical reactions required does not fully address the chemical engineering requirements.   None of the observers other than myself seems to seriously address the Sarin production issue from an industrial perspective.  A reasonable publicly available document produced by the now defunct US Office of Technology Assessment describes many of the engineering hurdles required for production of Sarin.  Sarin is not a substance that easily lends itself to home-brew or clandestine “drug-lab” type manufacture, principally due to the requirements to handle highly dangerous corrosive gases at high temperature.  I address some of these issues in summary form in my Bloomberg View op-ed column, but there is a deep well of information available if you are willing to research the history of the German nerve agent production facilities and the history and US production efforts at Rocky Mountain Arsenal, the facility in Colorado where the USA’s “unitary” Sarin was produced between 1953 an 1957.

One principle problem faced by anyone producing Sarin is that the last step of the Sarin process actually leaves you with a cocktail of Sarin and acids.  You get one mol of HF (hydrogen fluoride) or HCl (hydrogen chloride) for each mol of Sarin you produce.  Most of the production pathways will end with HF in the Sarin.  The US worked out a so-called di-di process (very hard to pull off, I may add) that ends up with HCl. Worked out in weight equivalents, if you make 1 kg of Sarin, it is going to be mixed with 140 g of HF.  This residual HF is nasty stuff, to say the least.   The residual acid, regardless of whether it is HF or HCl, is going to cause a number of problems.  First, the product will be corrosive to whatever container or munition that it is in, degrading the shelf life of the container or munition and eventually posing safety and handling problems from leakage.   Second, acidity causes degradation of the Sarin.   Third, HF vapor can defeat many types of protective clothing and equipment.  The acidic nature of the mix reduces the effective shelf life of the Sarin from decades to months.

The US, the Soviet Union, and to the best of my knowledge, the UK and Tito-era Yugoslavia had developed the ability to refine the residual acid out of Sarin as a final refining step.  I am not sure if anyone else was.  My initial research has not been able to indicate whether the original German Nazi-era production facility surmounted this problem.  Even the very large US production facility at Rocky Mountain Arsenal devoted many PhDs and millions of dollars to this effort and did not perfect the distillation process until well after production started.  Earlier batches were re-distilled once the distillation method was perfected.  The distillation of the residual acid was, and continues to be, a deeply protected dark art.  Some of the general information about the process, but not the details, is described in the engineering history of Rocky Mountain Arsenal.   It is my belief that the UK mastered this process at their facility in Nancekuke, Cornwall and that the USSR did so similarly in its production facilities.  The existence of long shelf-life Sarin in the Soviet-era stockpile is de facto evidence of this. I have spoken to several people involved in Tito-era Yugoslavian chemical weapons and they have indicated to me that Yugoslavia was able to remove the acid.  Saddam Hussein’s Iraq did not perfect the acid removal step of the process.  Chinese, Swedish, North Korean, and French Sarin efforts remain an enigma to me.

If you are planning to store your Sarin for a long time, you need to remove the residual acid.  However, this is not a terrible barrier if one is planning to use the Sarin quickly.  The Iraqi military used a “just in time” approach to Sarin production and made every effort during the Iran-Iraq war to use the Sarin that they produced quickly.  The Iraq Sarin production efforts are indicative that a nation state can produce the industrial infrastructure for Sarin but not have the acid removal step, either because they couldn’t do it or because it was too expensive to do.

The best way I can summarize the production issues in brief form is as follows:

• A bench-top or home-style setup is very dangerous.  Some lab scale production facilities using modern technology and techniques can create teaspoon-type quantities.  
• To get any reasonable quantity of Sarin you need a factory-type setup. Even a very expensive factory gets you only a moderate grade of Sarin.  The US OTA study estimated that you needed at least $10 million in 1993 USD to get a basic setup going, not accounting for effectively dealing with waste or safety issues or the refining process. 
• To get a high quality, acid-free, long-shelf life product, you need a lot more money and effort than just a base-level production facility.  Iraq wasn’t able to pull it off.  But if you don’t need shelf life, you needn’t bother with acid removal.  
• The Iraq experience shows that a large, multimillion dollar chemical weapons production effort can still produce a mediocre product.  

Salient points of the “Quality Argument”

In the various blogs and documents I have seen, the crux of the “Quality Argument” can be distilled down to four points. 

Point 1:  The UN report found multiple chemical impurities, indicating a deficient Sarin production.  This obviously means that it wasn’t produced by a state-level manufacturing program.

The Iraqi example shows us that a large and sophisticated chemical weapons production infrastructure can produce Sarin with significant impurities in it.  The presence of impurities is testament to how hard it is to remove them, not any kind of evidence of non-state manufacture.  

Point 2: Numerous odors were reported.  High quality Sarin is odorless

Indeed.  But this argument serves no great point one way or the other to tell who made it.  Pure Sarin is odorless.  But lower quality Sarin, which can be produced by a large state-run operation, will have impurities and decomposition products.  The residual acids will react to whatever the impure Sarin has been stored in.  If a binary device was used (see below), much of what may be smelled is precursors or byproducts rather than the Sarin itself.  Yes, there are many reasons why lower quality Sarin can smell funny.  But none of those reasons can be any kind of evidence to state that the Assad regime didn’t manufacture it. 

Point 3: No “stabilizers” were found in the Sarin residue.  Serious military grade Sarin has stabilizers

The purpose of so-called “stabilizers” in Sarin is to prevent corrosion during long-term storage.   In the US Sarin program in the 1950s, the additives were tributylamine and a chemical called N,N’-Diisopropylcarbodimide.  These chemicals were added to prevent corrosion of steel and aluminum.   If you don’t care about long term storage, you don’t need to add speciality additives.  If your Sarin is produced from binary components (see below), there is not any absolute requirement to add additives, particularly as shelf life is patently not a concern after mixing the two components. 

Point 4: Syria has admitted to a serious CW production program.  Such a program can’t make deficient Sarin.

This is simply not true.  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, largely due to the lack of an acid distillation step in the process.  I think that taking Syria’s admission of a nerve agent production facility as some sort of evidence that someone else made the Sarin in question is a truly epic feat of Orwellian doublethink. 

A quick tutorial on Binary Sarin

Many of the issues surrounding the continuing mysteries of the Ghouta attacks can possibly resolved if the Sarin used in the attacks was binary in nature.  I am increasingly of the belief that 8/21 involved a binary chemical warfare agent.  Chemical agents can be made in binary form – by combining two or more non-warfare agent precursor chemicals to create the warfare agent.  This is done for many reasons, to include safety and security.  To date, it appears that at least four different nerve agents (GB, GD, GF, and VX) can be made in a binary fashion.i  Iraq experimented with binary Mustard but could not make it into a tactically and economically viable weapon due to the low concentration of Mustard in the mix that was produced.

In the case of Sarin, a chemical known as DF (methylphosphonic difluoride) is mixed with isopropyl alcohol.  This chemical reaction results in Sarin and hydrogen fluoride (HF).  It is my understanding that this reaction is a bit violent, and the resulting HF in vapor form is in itself a highly toxic and corrosive substance.  For this reason, US binary Sarin weapons included a quantity of isopropylamine to react with the surplus acid.  

It would appear, both from the OPCW and various media activity that the Syrian CW program’s nerve agents are actually binary in nature, wherein Syria stores the binary components of Sarin and VX.  The OPCW states that Syria declared approximately 1230 unfilled munitions.  This fact implies that the mode of employment is to fill munitions prior to use, rather than manufacture and store filled munitions.  

In my experience, there are three theoretical ways to effectively field binary Sarin:

1. In-flight mixing.  One could put the separate components into the weapon system and have the mixing occur in flight on the way to the enemy.  This is much harder to do in practice than in theory.  The US spent a lot of time and money into getting the mixing in flight correct.  Even so, the project was plagued with errors and I am not convinced that the US ever fully resolved the in-flight mixing issues before the programs were cancelled. Iraq used binary Sarin.  
2. Mixing at the launch point.  Theoretically, the products can be mixed immediately prior to pouring into the munition.   This is an abysmally bad idea with Sarin.  This is very dangerous for the handler who has to do it and the reaction produced by combining the components is a very dangerous one. While it can be safely handled in a reactor vessel or inside a steel artillery shell,  doing this in a bucket on the side of the road may kill the handler and damage vital equipment due to the corrosive nature of the HF.  This may be a more viable approach with VX, though, as that reaction creates fewer acute problems.  
3. Mixing in the factory prior to shipping.  One viable concept of operations is to do the mixing in a factory setting with proper engineering controls to contain the reaction and the concomitant HF.  The munitions could be filled in the factory and sent straight to the field for use.  The OPCW’s reference to mixing and filling equipment could be taken as evidence that this is the approach in use in Syria. 

The proper employment of binary Sarin requires effective mixing and cannot be done without creating excess HF vapor.  A poorly executed binary mix will result in a cocktail of chemicals: some Sarin, some unmixed precursors, some byproducts – including HF. This could go a long way towards explaining the mix of casualties and odors during the 8/21 attack.  The precursors and byproducts are more in the category of general irritants than specific neurological poisons (as Sarin is) and are more likely to have strong odors. 

The Sarin Quantity Argument

The amount of Sarin that appears to have been used is a strong indicator of a national-level production program.

People often make assumptions about the efficiency of Sarin as a battlefield weapon.  There is a wide gulf between theoretical toxicity of Sarin in the laboratory environment and actual practical toxicity on the battlefield.   To make a very long story short, a lot more Sarin is needed to create death and injury than the layman usually thinks.   Even though Sarin is very toxic, a large number of casualties over a wide area will require a lot of chemical agent.  

In my recent article in CBRNe World magazinei, I use old military chemical target analysis methods to attempt to figure out how much Sarin may have been used.   These methods are too lengthy and obtuse to recite here.  Indeed, I had to summarize for the CBRNe World article due to a 2000 word article limit.   Basically, as a thought exercise, I pretended that I was Assad’s chemical officer and using old US charts and tables.  I had to make many assumptions and guesses, as some raw data was simply unavailable to me.   I came up with an order of magnitude estimate that the amount of Sarin for an attack of this nature would have been somewhere in the range of 370 kg to 4400 kg.  As is often the case, I believe that there are strong reasons why neither the bottom end or the top end of the range of estimates is likely to be the case.  My own instinct tells me we are looking at something roughly around a metric ton of Sarin.

A metric ton (-ish) of Sarin is not something that anyone is going to cook up without a factory.  Who is more likely to have done this?  An unnamed non-state actor or the state who has admitted to having the factory?  As previously stated, a significant amount of engineering is required to produce Sarin, even in small quantities.   It should be noted that the Aum Shinrikyo production facility, the only significant example of non-state Sarin manufacture, is an interesting comparison point. It cost a lot of money, was a large and custom-built three story building, was staffed by engineers and chemists, and used a front company to buy chemicals legally.   Despite this level of effort, the Aum Shinrikyo facility was only able to manage a modest production level of single batches of 2 gallons of Sarin. 

To make ton-level quantities of Sarin an industrial-scale factory is needed.  The level of difficult and the scale of the operation simply don’t permit it to be done in less than a factory setting.  Based on the German experience at their factory in Dyhernfurth, a ton of Sarin required about 8 tons of precursor raw materials.  Due to principles of conservation of mass, about 7 tons of waste material, much of it very dangerous, would be produced.  

The scale of the operation required to produce tons of Sarin, or indeed tons of DF (the critical precursor binary component) raises an interesting issue of economics.   Given the industrial difficulties, Sarin is extremely expensive in comparison to conventional alternatives, unless you run your Sarin plant for years and amortize the cost over the course of thousands of tons of product.  The expense, in terms of equipment and skilled labor, of such an effort means that one has to seriously question whether this is time, labor, and money well spent in pursuance of tactical military objectives.  One has to seriously question whether a cash-strapped insurgency is going to squander their resources on such an endeavor when that amount of money, tens of millions of dollars at a minimum, could be used for a lot of other purposes to greater effect.  Thirty million dollars buys a lot of conventional equipment that is much more immediately useful than a few tons of Sarin.  So, from an industrial and economic standpoint, the culprit looks to be the regime more than anyone else. 

Notes and Disclaimers:

1. This paper represents my personal opinion and does not represent any position or opinion of any previous employer.
2. I’ve used US spelling conventions and a US paper size instead of UK conventions.  I had to pick one or the other.  Criticisms on this point will be ignored. 
3. Information current as of 6 November 2013 was used for this paper. I have done rather a lot of research on chemical warfare agents over the years.   Some of the documents I have consulted are not generally available online.  They are in these quaint things called libraries.  Others are government documents that you might have to go to a special reading room to find or to request by Freedom of Information means.   If you can’t find a document I cite online, please don’t blame me.  The internet has a lot, but it doesn’t have everything. 
4. I firmly believe that Sarin, as a product trade name, should be capitalized.  I often lose this argument, but I continue to insist on this point. 

About the author: Dan Kaszeta is the author of “CBRN and Hazmat Incidents at Major Public Events: Planning and Response” (Wiley, 2012) as well as a number of magazine articles and conference papers.  He has 22 years of experience in CBRN, having served as an officer in the US Army Chemical Corps, as CBRN advisor for the White House Military Office, and as a specialist in the US Secret Service. He now runs Strongpoint Security, a London-based CBRN and antiterrorism consultancy and is also a Senior Research Fellow with the International Institute of Nonproliferation Studies.

A Detailed Examination Of The Range Of Munitions Used In The August 21st Sarin Attack

Thanks to John Minthorne, who has put together this detailed analysis of the range of one munition type used in the August 21st Sarin attack.  John Minthorne is a professional mechanical engineer with around seven years relevant experience.  His relevant experience includes process system design, project management, feasibility and conceptual studies, and computational fluid flow modelling.  The original report and associated files can be found here.

UMLACA Maximum Range Analysis

Abstract

This report attempts to establish, with a minimal level of rigor, the maximum range that can be assigned to the 330mm-class chemical rocket (the "unidentified munition linked to alleged chemical attacks [UMLACA]) used in the August 21, 2013 attacks on Ghouta, Syria. The report is based on public information including United Nations reports, NGO publications, amateur video & photography of the remains of the weapons, public weather data. In particular, this goal of this report is to determine whether this model of rocket could have been launched from the Syrian Army Republican Guard "base 104", approximately 9.5 km west of the impact sites.

Background

In the early morning of August 21, 2013, the Ghouta residential suburb of Damascus, Syria was struck by a rocket attack that killed hundreds. Representatives of the Syrian Army and rebel forces were quick to blame one another for the attack, and international observer countries including France, the United Kingdom, Russia, and the United States made official but predictable statements  blaming the "opposite side".

In mid-September, Human Rights Watch (HRW) and the United Nations (Sellström) released reports that confirmed the August 21st attack did make use of Sarin. Consistent with the UN Mission's charter, the Sellström report did not assign blame for the attacks. The report did, however, note the azimuth of the ballistic trajectories of two of the munitions used, including a UMLACA that impacted Ein Tarma. The Human Rights Watch, along with several news organizations, noted the the trajectory azimuths intersect deep in Syrian government-held territory, specifically the Republican Guard 104th Brigade military base.

However, this information is only meaningfully damning to the Syrian government if the UMLACA is capable of being fired approximately 9.5 km from the Republican Guard base to the impact site. Much of the flight path less than 8 km from the impact site is identified by Human Rights Watch as "contested" at the time of the launch (Lyons).

Whoghouta.blogspot analysis

One organization to estimate the maximum range of the UMLACA is whoghouta.blogspot.com (sasa wawa). This analysis reported in a maximum plausible range of 3.5 km and concluded that the rockets could not have been launched from the Republican Guard base. This analysis was qualitatively reviewed, and in the opinion of this author the analysis contains a number important flaws. Some of the more significant errors include:

• Assuming very short burn times (and wrongly stating that such an assumption is conservative). Drag increases as a function of more than the square of the velocity, and as a result the thrust of the rocket motor over time is a crucial consideration.
• Using hobby rocketry engines as the basis of design. By extension, underestimating the propellant mass and specific impulse.
• Miscalculating the center of drag, severely underestimating the rocket's stability.
• Failure to consider wind direction, elevation above sea level, or air temperature.

Summary of available information

Information for this report was gleaned from publicly available information:

• Published photographs and diagrams based on those photographs, by Human Rights Watch.
• Field measurements and photographs taken by the United Nations Mission.

Assumptions

• Secondary sources of ballistic error such as Coriolis forces are ignored.
• Additional assumptions are listed in the relevant sections of this study.

UMLACA Physical Properties

Propellant Mass

The total impulse of the UMLACA rocket motor is limited by the propellant selected and the volume of propellant used. Since the purpose of this study is to evaluate whether a 9.5 km travel distance can be ruled out, each physical assumption is listed as a range between which the actual values for the UMLACA likely fall.

The total length of the UMLACA is about 2200 mm. Some portion of the nose section is filled with a bursting charge and detonator, so the maximum length of the solid fuel volume is assumed to be 2000 mm. The UN report implies that the motor section may be as short as 1340 mm, so a more pessimistic assumption incorporating a void space inside the weapon's warhead would be a fueled length of 1300 mm.

The external diameter of the UMLACA is 120 mm. Assuming a robust, wall thickness consistent with standard weight pipe, an internal diameter of 110 mm is used. This results in a volume range of between 0.0124 and 0.0190 m3.

The density of high-performance solid propellants varies between 1.6 and 1.86 kg/L (Zandbergen). Applying this value range to the fuel volume range, the rocket's propellant mass is found to be between 19.8 and 35.34 kg.

Specific and Total Impulse

The specific impulse of a rocket motor will have a profound effect on its performance. As a motor becomes more efficient, it can increase the final velocity of a rocket exponentially higher. This effect is more muted in a subsonic or transonic rocket than in an orbital or sounding launch vehicle, however. Military propellants have specific impulses in the range of 210 to 260 s (2060 – 2550 N*s/kg) (Zandbergen). Multiplying this range by the propellant mass gives us a total impulse for the UMLACA of 40800 to 90100 N*s.

Maximum Thrust

Gases escape a rocket nozzle in a predicable fashion. The fluid flow velocity through the nozzle throat is Mach 1, such that the total thrust generated by a rocket motor varies roughly proportionally to both the chamber pressure and throat area (Platzek). Unfortunately, no information appears to be publicly available documenting the precise the throat area of the rocket motor. The Human Rights Watch report contains one photograph of the rear of the motor and a tape measure, allowing estimation of the nozzle throat to be very roughly 50 mm. Assuming a chamber pressure of 7 MPa, this would equate with a maximum thrust of around 22 kN. Given the very large amount of uncertainty on this number, no conclusions can be drawn from this. It is simply noted that the estimated maximum possible thrust is within an order of magnitude of the thrust a designer would desire for this weapon.

Thrust Characteristics

A solid-fuel rocket has a practical maximum burn time – the regression rate of propellant is lowest in a solid grain geometry, but is still non-zero. Regression rates for typical high-performance propellants vary from 5 to 25 mm/s (Zandbergen), corresponding to a theoretical maximum burn time of 80 s to 400 s for a 2 meter, solid grain rocket motor. The longest total burn time considered in this study was 45 s, well within the realm of feasible achievability.

The amount of thrust a solid-fuel rocket provides over the course of its burn broadly customizable by changing the chemistry and structure of the rocket grain. For a rocket with no lift and poor drag characteristics such as the UMLACA, maximum range will be achieved with a short, high thrust initial impulse followed by a long, low thrust burn to sustain velocity at low transonic speed (~0.7M or 240 m/s). A thrust/time profile of this shape is both achievable and commonly found in military rockets (Platzek).

Environmental Considerations

Wind

A rocket spends a significant amount of time in flight. In evaluating the maximum distance a rocket may travel, the velocity of the wind encountered must be considered. At 2:00 AM on the morning of the attack, the wind at Damascus International Airport was blowing from the WSW (about 248°) at a sustained speed of 6.9 miles per hour (3.1 m/s) and increasing (Weather Underground). Wind speed is typically higher a significant distance above the ground; for the purposes of this analysis the wind velocity is assumed to be an average of 4 m/s from 248° (37° from a pure tailwind from the rocket trajectory of 285°. Correspondingly, a rocket azimuth of 143° relative to a 4 m/s wind was used in the OpenRocket software trajectory models. For ~60 s long flights, this adds a few hundred meters to the range. If meteorological information shows that higher-altitude tailwinds were present, this could increase the maximum range by a high single-digit percentage.

Atmospheric density

Aerodynamic drag is proportional to the density of the fluid through which the projectile travels. The temperature in Damascus at 2:00 AM on the morning of the attack was about 73°F (22.7°C) – if a standard atmospheric temperature of 15° is assumed, drag will be overstated by about 2.8%. The elevation of the targeted area in Ghouta is about 760 meters above sea level – if sea level elevation is assumed, drag will be overstated by about 9.5%. Since the temperature profile of the atmosphere above Damascus is not known, trajectory models assumed a standard atmospheric temperature and a launch elevation of 760 m above sea level.

Relative elevations

A projectile on a nominally parabolic trajectory will travel a greater distance if its impact location is of lower elevation than if it flies over a flat plain. The topography of northern Damascus is dominated by Mount Qasioun, a 1151 meter high peak. The areas of Ghouta targeted are lower, around 760 meters above sea level. Since the rocket attack was obviously not launched from the peak of Qasioun, the actual difference in elevation was less than 400 meters. This difference in elevation is not considered in these range calculations, since the actual launch elevation is not precisely alleged. This means that the maximum ranges shown are conservative by a small degree (probably 0.1-0.2 km) due to the relative elevations of the launch and impact sites.

Maximum Range Calculation

Physical Rocket Model

A model of the UMLACA and derivative UMLACA with a more aerodynamic nose cone were created in the Open Rocket program. Both models were modified from a model downloaded from the whoghouta.blogspot web site. The models are described in the two tables below; dimensions are in mm, roughnesses are in um, and masses are in kg (unless noted otherwise).

Drag Modifications

Any designer tasked with extending the range of the UMLACA would immediately consider improvements to the rocket's drag. With a Cd of about 1.0, the rocket's drag is several times the value to which it could be reduced with relatively superficial modifications. The nearly blunt front of the rocket generates about 80% of the subsonic total drag.

The UN and HRW reports both sketch the UMLACA with a completely blunt end, but the least is known about the front portion of the rocket because it is damaged upon use by the bursting charge and subsequent impact with the ground. The front plate includes six threaded holes which could be used to attach a light-weight aerodynamic nose cone. As such, the possibility that rockets fitted with nose cones were used on August 21 cannot be ruled out. Since addition of an aerodynamic nose dramatically changes the maximum range of the UMLACA, maximum ranges were established both with and without the aerodynamic nose cone.

Rocket Motor Design

Six hypothetical rocket motors were evaluated, three per drag condition of the UMLACA. All utilized an initial boost phase to accelerate the rocket to about 0.7M (240 m/s), followed by a lower sustainer thrust to maintain flight speed. Two used total impulses of 40800 N*s, the lower end of the estimated motor impulse. The remaining motors used the higher end of the estimated impulse, about 90100 N*s. The full .eng data for each motor can be found here.

Software Limitations

For convenience, this study matched the "whoghouta" blog's selection of Open Rocket as the software to simulate the UMLACA trajectory. The UMLACA is several times larger than a typical large single-stage hobby rocket, and its characteristic geometry likely challenges the software in ways that were not the focus of its development.

Simplification of Fin Layout

The Open Rocket software does not support modelling of a circumferential band around the perimeter of the tail fins. This band is parallel to the air stream, generating significant drag as well as contributing to the stability of the rocket. To model the ring's contribution to drag and efficiency, the fin height was increased from the actual dimension of 95 mm to 135.6 mm, replicating the total fin material area of 0.179 m2.

In addition, the enclosed nature of the air stream through the fin assembly may create directional flow effects more pronounced than a more simple fin arrangement. Study of the airflow through this fin assembly is an excellent candidate for further study of the UMLACA's aerodynamics.

Transonic and Supersonic Drag Performance

The UMLACA is likely but not certainly an exclusively subsonic weapon. The coefficient of drag of an object in a fluid flow stream is not constant; it changes with velocity. At about M0.8 the Cd beins to increase, peaking locally at M1.0 and dropping to an intermediate value for low supersonic values (Heinrich). The Open Rocket software attempts to model these changes in Cd, but for a rocket with such an unusual shape as the UMLACA it is likely that the modelled transonic behaviour is not fully accurate.

Results

For the UMLACA without drag-reducing features, the maximum distance travelled was about 6.5 km, for the UMLACA4 motor curve at a launch angle of 43° from vertical. Maximum distance travelled using a 41 kN*s motor was about 3.3 km.

If the UMLACA weapons used in the August 21st attacked had aerodynamic nose cones, their maximum range could be in excess of 15 km. With a range of 15 km, the UMLACA5 motor curve did not produce the greatest travel distance but its lower average thrust kept the more streamlined rocket at transonic speed (increasing confidence that the simulation is accurate).

Conclusions

• The rocket with a blunt nose has mediocre drag characteristics. A designer seeking to maximize the weapon's range could add a nose cone to the weapon, which would greatly reduce the drag coefficient and increase the range. The presence of threaded holes on the front plate of the rocket could be an indication that this was, in fact, done.
• The rocket is aerodynamically stable and unlikely to tumble or excessively oscillate in flight.
• The publicly available information on the UMLACA (particularly the chemical variant) leaves a large margin of doubt as to the rocket's range and flight characteristics.
• On the basis of the publicly available information referenced in this report, an attack from the Republican Guard 104th Brigade base cannot be ruled out as implausible.
• The maximum range of the UMLACA is probably between 3.3 km and 6.5 km, increasing to 15 km if a nose cone were installed.

A Chemical Weapon Specialist's Thoughts On The UN Visit To Syria

With the arrival of a UN team in Syria searching for evidence of chemical weapon use in Syria I asked Dan Kaszeta, a chemical weapons specialist, some questions about the investigation.

In general terms, what do you think the UN investigation will involve?

I have no direct experience of UN investigations.  Indeed, this sort of investigative expedition is a rare event with relatively few precedents  What I can do, is speculate as to what I would do  if I were in charge of the investigation.

The UN is scheduled to visit Khan al-Assal, the scene of an alleged chemical weapon attack some months ago, with Russia claiming sarin was the agent used. What is the likelihood of the UN team being able to detect sarin at the scene of the attack?

If sarin had been used at Khan al-Assal, the likelihood of sarin actually being found in some form some 5 months after the alleged event is extremely small.  Sarin evaporates quickly.  It is classified as a non-persistent agent for this reason.  The vapour pressure of sarin is similar to water.  It evaporates at about the same rate as water on a very dry day.   Syria is a warm, dry climate.  Even if Sarin had been used, which, based on various information I have seen is unlikely, it would be long gone.  This is the scientific equivalent of pouring a bottle of vodka in your garden and going back over a month later trying to find the vodka still there.  It isn't a rational expectation and it isn't supported by basic science.

There is also the concept of “scene integrity” to be considered.  The Khan al-Assal site is an alleged crime scene that has been unsecured for five months.  People and objects have come and gone.  There is ample opportunity for things that were at the crime scene to be removed and there is ample opportunity for things that weren't at the crime scene.

There are some relatively rare circumstances wherein a sample of sarin might still be available after this time:

• An unexploded, sealed munition that did not function as intended. 
• A shell or rocket fragment collected within a few hours of the incident and sealed in a jar or sealed plastic bag.
• A shell or rocket fragment containing sarin liquid embedded in some other matter in a way that would prevent evaporation or hydrolysis (reaction with ambient moisture).   

However, given the extreme concerns about the scene integrity, chain of custody, and the time elapsed, the validity of such evidence would be suspect.

There were some reports at the time of a strong smell of chlorine at the scene of the attack, would that be detectable at the scene of the attack?

There are far too many chemical compounds that could potentially cause a “chlorine smell” to make any definitive conclusions.  It should be noted that a chlorine smell is not at all associated with any category of nerve agents.   Also, odours are base on gases, vapours, and aerosols.  There’s no rational expectation that a gas, vapour, or aerosol could be present after the passage of this much time.  In addition, the “scene integrity” concerns above still apply. 

Would it be possible to detect the use of sarin in the blood, hair, urine, or tissue of victims, both the dead and the survivors?

There’s lots of scientific work that has been in this area, as I noted in a previous paper on this subject.  The issue is elapsed time.  There’s little scientific/academic work that addresses the issue of forensic analysis after such a lengthy period of time.  Again, one must view “survivors” and dead bodies as evidence.  Where have they been for this period of time?  There’s no chain of custody or scene integrity. 

Several months after the attack, would victims of the attack still present any symptoms?

It seems highly unlikely.  There is some evidence of miosis (pinpoint pupils) being visible for weeks after exposure, but we are talking about many months in this situation.  

The Russians have claimed a very specific type of rocket was used.  Assuming the remains of the rocket were available to be examined, would the UN team have any chance of being able to confirm it was used to deliver a chemical agent, and would they be able to detect sarin on it?

I think that it is much more likely to be able to evaluate the shape and construction of the rocket to see if it is consistent with a chemical weapon, or if it is more consistent with a conventional explosive rocket. 

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More details posts on chemical weapons in Syria can be found here, including more from Dan Kaszeta on sarin.

You can contact the author on Twitter @brown_moses or by email at brownmoses@gmail.com

Chemical Weapon Specialists Talk Sarin, Saraqeb, and Khan Al-Assal - Part 2

Here's the second set of answers from two more chemical weapons specialists on the use of chemical weapons in Syria.  Part one can be found here.

Dan Kaszeta, a US Army Chemical Corps veteran, provides some very detailed answers on sarin.

What form does sarin take?  

Sarin (also know as GB) is a liquid at normal temperatures.  It has the appearance and general consistency of water. The term “sarin gas” is misleading.  It is not a gas at normal temperatures. (For example, chlorine is a gas at room temperature.)  It is liquid between the temperatures of -56º C and approximately +150º C, although it evaporates in proportion to the temperature.

Sarin has a viscosity (how thick the liquid is) slightly higher than water, although my own experience is that you can’t tell with the naked eye.  

Vapour pressure. Sarin has a vapour pressure.  In other words, it has a tendency to evaporate into a vapour state from liquid state, just like many liquids.  Water, alcohol, petrol, acetone, etc. all have vapour pressure.   Sarin has a slightly lower vapour pressure than water.  This means (all other factors being equal) that a drop of Sarin at 25º C should evaporate slightly slower than a drop of water.  In practice, it often evaporates quicker than water.  I’ve seen a drop of water next to a drop of Sarin on the side of a rifle in a test chamber. This is because there is already water vapour in the air (i.e. humidity).  So, the rule of thumb that I learned is that Sarin evaporates like water in the desert.  

It should be noted that at high temperatures, Sarin evaporates very quickly.  This makes it a “non-persistent” nerve agent.   At room temperature or higher, terrain, clothing, equipment, etc. will not remain contaminated for long periods of time as any liquid droplets will evaporate.  This is in contrast to so-called “persistent agents” (e.g. GD, VX) which have lower vapour pressures and evaporate much slower. 

Sarin vapour is heavier than air.  

Can it be liquid, gas, powder, etc? 

The best way to describe Sarin is that it is a liquid that gives off vapours.  It should be noted that many ways of dispensing Sarin (see weaponisation below) cause the formation of an aerosol – a finely divided cloud of droplets.  Aerosols behave much like gases and vapours.   

“Dusty agents”/ Powder: There’s no way that I know of to dispense Sarin as a solid or powder, although I can’t completely rule out the possibility that someone has developed a “dusty agent” form of Sarin.  There is some literature out there on the possibility of “dusty” chemical warfare agents.  As far as I know, this was only ever a possibility with really low vapour pressure agents, not fast evaporating agents like Sarin. The only benefit I can think of for making a “dusty sarin” (in reality, not Sarin as a powder, but small particles impregnated with sarin) would be to slow down the evaporation time of the Sarin… i.e. increase its persistency.   But doing so would decrease the rate at which the agent is dispensed in vapour form, thus reducing its immediate lethality somewhat.  And immediate lethality is the point and purpose of Sarin.   It would seem to have little utility and an awfully difficult way of engineering some persistency into Sarin.  It would be far easier to use a more persistent nerve agent instead.  Or it may be possible to thicken Sarin with an additive. The US government applied for a patent to do so in 1969.

Does it have a particular smell or colour?

It is colourless.  Pure sarin has no odour.  Even if it did have an odour, it would be difficult to tell as a concentration detectable by a human nose is probably a lethal exposure.  

How is sarin typically weaponised?

By “weaponised” we generally mean “how is this chemical put into a device or munition in order to function effectively on the battlefield. In order to answer this question we must apply the characteristics of the liquid Sarin to the battlefield environment.  Because of its physical and toxicological characteristics, the most useful methods of employment for Sarin or any other non-persistent nerve agent are means and devices that rapidly disperse droplets or aerosols in a concentration high enough to cause immediate casualties. Dispersing a payload of Sarin in one load of liquid all in one place (like dumping a bucket) causes a great hazard in one spot, but not wide effects.  A device that did this would be less useful than a conventional explosive device of similar size.  Likewise, dividing it too finely over a large area will cause it to disperse quickly and not have a concentration adequate to cause incapacitation or death.  Again, such a device would have little or no value in comparison to a conventional device of similar size, weight, or shape.   

The overall guiding principle for weapon design with Sarin was that is was meant to rapidly cause casualties, and as such, weapons/munitions were designed to detonate/disperse at ground level.  (As opposed to persistent agents, which are designed to contaminate terrain and equipment, which generally burst/dispense/detonate some meters above ground level in order to spread a radius of droplets.) During the Cold War, the various superpowers devoted a lot of time, expertise, and money to studying and testing various weapon designs to see how effective different munitions and configurations might be.  Rather a lot of this information is now out in the public domain, either directly in form of declassified documents or indirectly, e.g. we can see the types of weapons that were the result of testing and optimisation and draw our own conclusions as to what types of weapons work and which ones don’t.  Drawing on US and Soviet experience, the following are the classic weapons for dispensing Sarin on the battlefield, all fuzed to detonate at surface:

• Artillery shells 
• Mortar shells 
• Air dropped bombs 
• Cluster bombs
• Missile warhead
• Rocket warhead
• Land mine

It should be noted that some types of weapons that aren’t so good for Sarin:

• Hand grenade – Very small payload possible.  Possibiity of leakage killing soldier handling it.  Soldier likely to have to be in protective gear the whole time.  Soldiers throwing grenades in protective gear are probably going to be less accurate and achieve less distance.
• Grenade launcher round – same liabilities as hand grenade.  And very low payload.
• Aerial spray devices – Unless the helicopter or aircraft is almost at ground level (highly unlikely), the Sarin would be too dispersed to have much effect.  Aerial spray devices are better for more viscous persistent agents (like Mustard or VX)
• Anything fuzed for aerial burst.  Likely to spread the droplets 
• Any explosive dissemination device with too little or  much explosive.  I won’t specify what it is (for obvious reasons) but there is an optimum ratio of charge to agent.  Too little leaves a puddle, too much spreads it too thin.

Some notes about types of “agent fills”.  An “agent fill” is a term that describes exactly how the chemical warfare agent is configured inside.  There’s three basic kinds of agent fills:

• Unitary: This means the agent is in the weapon in one big pool.  
• Binary:  Binary fills mean that two separate components are mixed to created the chemical agent.  Generally, this is done for the purposes of safely handling the munitions and to avoid having to store chemical weapons or filled munitions.  Sarin could be mixed on-site and poured into empty shells/rounds or munitions could be designed to mix two different components in flight.  To my knowledge, this was done with GB and VX.  A well-made binary weapon would have little or no difference from a unitary fill.  A poorly made one would have a high dud rate and would be generally less effective.
• Submuntions: A highly effective way of dissemination would be a munition that scattered bomblets or submunitions at some height, with the submunitions designed for ground impact detonation.  Other factors being equal (…but they often aren’t), submunitions are generally considered a more efficient method of dispensing Sarin.  

A note about “dud rates.”  Any class of munition has a dud rate, i.e. the percentage of shells/rockets/etc. that fail to function as intended.  Anecdotal evidence is that some older chemical weapons may have quite high dud rates. Even many modern conventional artillery rounds have non-trivial dud ratesv there’s no physical mechanism to explain why chemical rounds would have a radically lower dud rate.  This means that if any significant use of chemical warfare happens, there’s going to be an unexploded shell out there somewhere, which will be of great intelligence value if it can be safely retrieved.  (A task not for amateurs!)

Have you ever heard of sarin being used in a diluted form, or mixed with other chemical substances to make it less lethal?

There seems to be little point in trying to dilute Sarin to have some kind of non-lethal effect and I have no knowledge of this ever happening.  The sub-acute, low-level signs and symptoms of nerve agent poisoning are annoying but not terribly debilitating.  Giving a bunch of people a runny noses and pin-point pupils has far less tactical usefulness than using conventional riot control agents or the generally non-lethal vomiting agent adamsite. Such agents can easily cause debilitating effects, whereas with nerve agents, there’s a fine razor’s edge, not easily (or at all) controllable between incapacitating dosage and lethal dosage.  Why risk the opprobrium of the international community and the possibility of triggering international intervention by using just a wee bit of Sarin?  There seems no point. 

Sarin is designed to injure and kill.  There’s not much leeway between the incapacitating doses and lethal doses with Sarin (1000 mg and 1700 mg respectively as the ED50 and LD50) and the concentration that would lead to a person absorbing 1000mg Sarin would quickly lead to absorption of a lethal dose of 1700mg. 

A number of reports have claimed to have proven the use of sarin through tests on hair, clothing, blood, tissue, and urine samples.

I will address each of these types of samples in turn:

Blood: 

Sarin can be directly and indirectly detected in blood samples.  Several methods have been studied for detection of sarin in blood. Several studies have been described in the academic literature. There are also indirect methods that detect decomposition products of sarin or the physiological effects of sarin. 

Experience from the Tokyo subway incident in 1995, documented by the OPCW shows that one of the decomposition products of Sarin is a chemical known as IMPA is detectable in blood.   

Sarin’s method of action is to inhibit a substance called acetylcholinesterase, which is used by the human nervous system.  At least one study shows that the presence of a nerve agent could be deduced by examining post-mortem blood samples for presence or lack of acetylcholinesterase, up to a week after death.  A person who has died from Sarin exposure would have little or no acetylcholinesterase present.  It should be noted that this would only indicate the presence of a nerve agent and would not specifically indicate Sarin versus any other nerve agent (or even organophosphate pesticide intoxication) nor would it conclusively indicate nerve agent as a cause of death, as other factors may have killed the victim, such as conventional trauma. 

Urine

One of the decomposition products of Sarin in the human body is methylphosphonic acid.  A study shows that this substance is detectable in urine by use of mass spectrometry.   This particular substance is not specific to Sarin.  (The journal article says it is a decomposition product of cyclosarin, Soman and one type of VX as well.)  It should be noted that it can take some time for chemicals absorbed in the human body to end up in urine.  An immediate post-exposure sample may not have any evidence of exposure.

Tissue

A study from 2004 using guinea pigs indicates that plasma, heart, liver, kidney, and lung samples can indicate the presence of either Sarin or Soman using gas chromatography and mass spectrometry.  

Clothing, Skin, or Hair

Clothing, skin, or hair could get contaminated by droplets of Sarin.  I cannot find any literature on the absorption of Sarin into human hair, but common sense would dictate that any water-like liquid could be trapped in hair.  Because of the rapid speed at which Sarin evaporates, a sample would need to be collected quickly and kept in a sealed container.  A lowered temperature would help.  In such a case, the Sarin might actually be most easily identified in vapour form in the headspace of the container, having desorbed from the sample itself. 

How would these samples be tested for the presence of sarin?

First of all, my expertise is not very strong in the laboratory techniques used for such analysis.  My expertise is strongest in field detection techniques.  To the best of my knowledge, the generally accepted gold-standard analytical technique is the combination of gas chromatography and mass spectrometry (GC/MS) which is widely used by chemists to identify molecules.  GC/MS is a sophisticated technique requiring training and expensive equipment mostly found in labs.  There are some portable GC/MS devices, but they are generally used in vehicles or mobile labs and aren’t handheld devices.  

The following are field technologies which also have relevance in laboratory settings, given the appropriate equipment. All have pros and cons.

• FTIR:  Fourier transform infrared – Used to analyze a gas, vapour, liquid, or solid sample.  Not real time. An identifier, not a surveillance or detection tool.
• Raman: Laser-based identification technique that can identify liquids or solids. Not real time. An identifier, not a surveillance or detection tool.
• Ion Mobility Spectrometry (IMS):  Fast acting analysis of gas and vapour. IMS is the backbone of military field electronic nerve agent detectors. Works very quickly and is very sensitive.  Some problems with false positives, varying from model to model.  Some units will only detect, others will identify as well (i.e. discriminate VX from Sarin), while others provide a qualitative (“Hi, Med, Low”) or quantitative (“25 mg/m3”) measurement.
• Flame ionization: Used by a family of French chemical warfare detectors.  Broadly similar to IMS in application
• Photoionization: Commonly used in civilian HAZMAT detectors.  Generically detects toxic gases, but cannot identify chemicals.  Would not be able to tell difference between, say, ammonia, acetone, and Sarin.  I only mention this because it is so prevalent in civilian fire departments. 
• Wet chemistry: A variety of manual chemistry techniques ranging from very sophisticated to very simple.  Too many different kits and tools to generalize, other than to state that the cheap tools are easy to use but not very specific, whereas the expensive tools can be good but hard to use.  There are some specific nerve agent detection techniques in this category, but they generally have difficulty discriminating between types of nerve agent.  

If sarin was detected in hair and urine wouldn't that suggest small, non-lethal quantities, being ingested over a period of time?  

Sarin detected in hair might theoretically be a small droplet that was in the hair as a direct result of a Sarin attack.  However, the sample would have to have been collected quickly and sealed up.  (See above)  I don’t know of a biological mechanism that would result in Sarin or byproducts ending up inside human hair through hair growth.  I checked the literature and found nothing in this regard.  

As far as urine is concerned, I can’t find direct literature in my cursory search about how quickly Sarin or decomposition products end up in urine.  However, Sarin acts on the bladder and kidneys rather quickly, so this cannot be ruled out.  One Japanese Sarin victim of the lesser-publicized Matsumoto incident (previous to the infamous Tokyo incident) had measurable Sarin decomposition products in his urine. 

If sarin was on clothing how hazardous would it be to handle that clothing without correct protection?

Very hazardous.  Depending on the amount of contamination, possibly lethal. Full head-to-toe protection would be needed.  The fastest acting hazard would be vapour from the clothing.  

Is it possible other substances could produce false positives for sarin?

Yes.  Generally, the more sophisticated and expensive the detection technique, the less scope for false positives.   The false positives depend entirely on the detection method.  IMS is often fooled by chemicals of the same molecular weight as sarin.  Organophosphate-based pesticides are very similar chemicals to nerve agent chemical weapons, so they may pose a false positive. 

After a suspected sarin attack how should the victims be processed, and what precautions should be taken?

An effort should be made to triage the victims and deal with the most severely affected ones first.  Triage guidelines are available in various resources. The general acronym ABCDD can be used to describe the field medical interventions required for nerve agent exposure.  This stands for Airway, Breathing, Circulation, Drugs, and Decontamination.  A general broad guideline for dealing with a serious sarin casualty is as follows:

• Move casualty out of danger.  If possible remove contaminated clothing
• Establish and maintain airway, through intubation if necessary
• Control secretions through suction
• Ventilate with oxygen if available, using bag-valve mask if necessary.  Regular air is better than nothing if oxygen is not available. 
• Monitor pulse, commence compressions if pulse stops
• Administer atropine, pralidoxmine (or other oxime, in accordance with local protocols), and diazepam via intramuscular injection.  
• Decontaminate any possible skin exposure.  Soap and water are fine, if specialty decontaminants are not available. Even plain water will work in a pinch. Flush eyes with water. 
• Establish IV access to allow further antidote administration
• Administer additional antidotes as required
• Move to definitive care
• Constantly reassess airway, breathing, and circulation en route. 

If these precautions are not taken what is likely to happen to the people coming in contact with the victims?

If the victim was only exposed to Sarin in vapour form, which is quite possible, then there’s no particular hazard.  If a victim has been exposed to droplets or liquid, then persons coming into contact with the victim are likely to be affected if they are unprotected.  Due to the rapid rate at which Sarin evaporates, the principle hazard will be respiratory hazard, although contact hazard risk cannot be eliminated.  Droplets on skin, hair, and clothing are likely to evaporate and pose a respiratory hazard both to the victim and bystanders/helpers.  

How long would it take sarin to become harmless, or dissipate?  In general terms are we talking minutes, hours, weeks? 

Minutes to hours, depending on wind and air temperature and the volume of liquid sarin.  Sarin liquid evaporates quickly.  Vapour will disperse quickly in the open, but could last a very long time in a combined space. 

Steve Johnson is Lead for Explosive and Hazardous Forensics at Cranfield university

Sarin

How is sarin typically weaponised?

Militaries have used a wide range of techniques. Artillery shells, missiles and rockets are probably the most commone, although drop/spray tanks and even jet engines (Russia) have been tried. In Tokyo it had been intended initially to aerosolise but ended up being stabbed bags left to evaporate (which is pretty good due to the speed at which it evaporates).

What form does sarin take?  Can it be liquid, gas, powder, etc? Does it have a particular smell or colour?

Its normal state is liquid, although it steadily evaporates at a similar rate to water. Its Boiling point is 158 degrees C, Freezing point is -56.

It’s unlikely to be a gas although it may be produced as an aerosol from a mechanism. It would not be a powder unless it was absorbed on to a powder or solid in order to produce one.

Have you ever heard of sarin being used in a diluted form, or mixed with other chemical substances to make it less lethal?

Not to make it less lethal – Binary production of sarin from separate less lethal and often more stable chemicals is practical and has been done in the past. The Tokyo attacks often refer to dilute sarin but that was unlikely to have been to make it less lethal.

A number of reports have claimed to have proven the use of sarin through tests on hair, clothing, blood, tissue, and urine samples.  How would these be tested for the presence of sarin?

The metabolic uptake of Sarin and its behaviour within the body is relatively well studied. For tissue samples there are a number of markers that investigators can look for and there efficacy is dependent on the time after exposure and the route of introduction (inhalation will get it in to blood fast, presence in urine is often many hours after exposure). Markers that can be looked for are:

• Sarin – unreacted pure sarin.
• Acetylcholinesterase(AChE and Acetylcholine – This only gives an indication that the nervouse system has been disrupted , potentially, but not exclusively by a nerve agent or substance behaving like one.
• isopropyl methtylphosphonic acid (IMPA) – a breaking down of Sarin, sometimes called the hydrolysis product. Pretty good and a number of studies have looked at its detection in blood and urine of Tokyo victims. Fairly hard to think of reasons for it to be in blood other than exposure to sarin.
• methyl phosphonic acid. A further breakdown product but with more potential causes.
• Macro molecules from other Sarin/protein interactions (Phosphylated tyrosine). Not impossible and potentially good for investigation longer after the exposure point.
• Butyrylcholinesterase.  While AChE is found more in the red blood cells BuChE is found more in the serum of blood. It is less affected by Sarin, but in the event of a high exposure you would expect to see it affected as well and this can be a good ratio to examine when trying to assess exposure history with samples that have a poor patient history (much like we currently have).

Different markers fall away at different times after exposure. IMPA tend tobreakdown to MPA. Ache levels return to normal after about 30 days.  BuChE around 50 days.

If sarin was detected in hair and urine wouldn't that suggest small, non-lethal quantities, being ingested over a period of time?  

Potentially. Or a small single dose. Again working up a full spectrum of the biomarkers should be able to help understand that.

If sarin was on clothing how hazardous would it be to handle that clothing without correct protection?

It’d be pretty stupid but if it were pure(ish) sarin then it evaporates at about the same speed as water. So in many cases the levels left could be very low.  Some countries are fairly casual about contamination of items that have been in the vicinity of sarin because they don’t believe the vapour condenses on surfaces easily – i.e. being near some sarin won’t contaminate you or clothing  unless you touch it. That’s not necessarily a universally accepted fact though.

Is it possible other substances could produce false positives for sarin?

In the medical tests – yes as discussed a little above. IMPA and Phosphorylated tyrosine are pretty good though. In any event though they would still be indicating a significant chemical injury to the person from a pesticide perhaps. That’s why it is so important to have a context and medical history of the person from whom the samples are taken in order to make a diagnosis. It is a fact of modern medicine that a large amount of diagnosis is based on symptoms and context/case history – which is one of the reasons people are so twisted about these samples. They need context no matter how good the test.

After a suspected sarin attack how should the victims be processed, and what precautions should be taken?

I actually think PHR have a very good fact sheet on this.

If these precautions are not taken what is likely to happen to the people coming in contact with the victims?

It really depends on the amounts of agent and how the people were exposed. You could treat sarin victims with no protection and be ok, perversely those exposed to CS will (and there is a lot of evidence of this in civil cases) present a very high hazard to medical staff due the the difficulty in decontaminating riot control agents.

How long would it take sarin to become harmless, or dissipate?  In general terms are we talking minutes, hours, weeks?

Minutes in Syria during the day.

Saraqeb

The Saraqeb attack is probably one of the mostly well documented alleged chemical weapon attacks of the conflict.  Canisters inside containers filled with white-grey powder were reportedly dropped from a helicopter, landing in two locations, one near a road, where no victims were reported, and the other in the courtyard of a family home.  It was reported that immediately after impact, one of the residents entered the courtyard, and collapsed shortly afterwards, later dying.
Shortly after the first victim entered the courtyard more members of the family entered, and also fell ill, as did people responding to the attack.  Between 11 to 13 people were reportedly effected, with only one death reported.  Video from the road-side location filmed some time after the attack would show children playing near to the remaining white-grey powder with no ill effects reported. (A more detailed breakdown can be found here)

Would the above scenario match what you'd expect to see if Sarin has been used in the attack?

Not really. The powder is unusual and the death rate is very low. It’s certainly not what one would normally expect.

In common with many alleged chemical attacks in Syria the medical staff appears to have no protective gear.  If this was a sarin attack, how likely would it be that the medical staff would be effected, and how long would it take for the medical staff to become effected?

This depends on if the patients are externally contaminated. They may just have inhaled it. Speed of action on medical staff if they were contaminated would depend on the level. If very low there may be no real noticeable effects given the general alarum in a casualty receiving post. If significant then within minutes. In fairness though the fact there is a patient and not a corpse would suggest that the level of contamination is low or the agent is non-lethal. As death from Sarin is pretty rapid.

One video shows a car pulling up with at least one victim inside.  If this was a sarin attack, how likely would it be that the inside of the vehicle would be contaminated by sarin?  If the victim inside the vehicle had been exposed to sarin is it likely other passengers in the vehicle would fall ill?

Syrian vehicles are far from airtight. If the victim had inhaled then there is no real reason for the car to become very contaminated. Potentially the victim migh exhale some contamination (this certainly happens with cyanide suicide).

Some people have proposed a scenario where a diluted mixture of sarin and other substances was used in the attack.  If that was the case, would your answers to the above questions change significantly?

Not really other than it might be possible to create a powder with another substance.

The canisters recovered from the scene of the attacks matched canisters also recovered from an attack reported in Sheikh Maqsoud in Aleppo, where there were again claims of them being dropped from a helicopter, with photographs showing the canister remains covered in white-grey powder.  

The same design of canister has also been filmed in a cache of weapons reportedly captured by the Syrian opposition from the Syrian military, and a journalist in Syria has shown the image of the canister to various armed group, many of which have claimed to have seen them in the possession of opposition fighters, claiming to have captured them from the Syrian army.

Another type of grenade, using an identical fuze, was also photographed in Syria, with the photographer being told it was a normal smoke grenade.

There's video footage from the Saraqeb attack showing what's claimed to be the canisters falling through the sky, appearing to produce smoke or a white gas, as well as producing light. The canisters appeared to show signs of heat damage around holes along the body of the canister.  

Considering the various information gathered about these grenades is it likely they would have contained Sarin?

Not really – sounds like WP or CS

Is it possible the could have contained another substance that could have caused symptoms seen in the victims of the attack?

In the grenades? Seems far fetched and the mixing of liquid sarin and a riot control agent dissolved in to solution would be a beast to get stable as it could affect agent stability.

Could one of those possibly substances produced a false positive for sarin?

Not as far as causing death and not on the basis of the medical test results.

Is it reasonable that the contents of this grenade could have been emptied and replaced by sarin?

Possibly.

Khan al-Assal

The Russian government has claimed the Syrian opposition was responsible for the Khan al-Assal attack, with a DIY rocket delivering a payload of Sarin.  

What do you think would be involved in putting together a DIY chemical warhead for a DIY rocket?

Crude devices are not that hard. Removal of explosives or whatever payload had been carried, followed by introducing the agent. You would need protective gear and it wouldn’t be very safe doing the filling.

Accuracy would be lost (if a missile) and performance of rockets could be affected by different weight distribution. I don’t really want to go in to too much detail about the how, lest I give ideas or advice, but early CW munitions were very simple.

If you don’t really care where it goes then its achievable.

Considering the Russian government's claim that a DIY rocket was used  in the attack, what would be the most effective dispersal method once the rocket reached it's target?  

Air burst or base ejection were used by military munitions but require more complex fuses. If aimed at hard targets then you’d get a level of dispersal by simple impact, but if it hit the earth then the payload could just get driven in to the earth.

As with the other alleged chemical attacks in Syria the staff treating the wounded appear not to be using any protective clothing.  Would this have resulted in medical staff and responders being contaminated if this was a sarin attack?

Not necessarily, see above.