Today is the 99th anniversary of the first massive chemical warfare attack. The agent of choice was chlorine. About 150 tonnes of the chemical was released simultaneously from around 6,000 cylinders over a length of 7 kilometres just north of Ypres. Lutz Haber—son of the German chemical warfare pioneer, Fritz Haber—described the opening scenes in his book The Poisonous Cloud (Clarendon Press, 1986):
The cloud advanced slowly, moving at about 0.5 m/sec (just over 1 mph). It was white at first, owing to the condensation of the moisture in the surrounding air and, as the volume increased, it turned yellow-green. The chlorine rose quickly to a height of 10–30 m because of the ground temperature, and while diffusion weakened the effectiveness by thinning out the gas it enhanced the physical and psychological shock. Within minutes the Franco-Algerian soldiers in the front and support lines were engulfed and choking. Those who were not suffocating from spasms broke and ran, but the gas followed. The front collapsed.
The impact of this gas attack surprised the German Imperial troops too. Their cautious advance behind the chlorine cloud, their hesitation in the confusion about what was happening despite having secured their initial objectives within an hour, and their halt after darkness fell meant that they almost immediately lost the strategic surprise. They would never regain it.
A first generation warfare agent in worldwide industrial application
How ironic it is that today, almost a century later, the latest chemical warfare allegations in the Syrian civil war concern chlorine once again. Everybody knows about the dangers of the chemical element, but nobody really considers it any longer as a militarily useful agent. At least not in standard warfare scenarios.
Chlorine and derived products are in massive industrial production. According to the World Chlorine Council, there are more than 500 chlor-alkali producers at over 650 sites around the globe, with a total annual production capacity of over 55 million tonnes of chlorine. Based on the low threat assessment and its wide relevancy to the chemical industry and trade, the Chemical Weapons Convention (CWC) does not even list it in Schedule 3 of toxic chemicals (Phosgene, another widely used chemical and World War 1 agent, is).
An oversight by the CWC negotiators? Hardly. Books on the toxicology and treatment of chemical warfare agents published between 1992—year of successful conclusion of the negotiations—and 1997—year of entry into force of the CWC—hardly mention chlorine. Chemical Warfare Agents, edited by Satu Somani (Academic Press, 1992), presents a few scattered references, mostly in relation to other agents or public health. Another book featuring the same title, written by Timothy Marrs, Robert Maynard and Frederick Sidell (Wiley, 1996), gives it a four-line acknowledgment in the opening historical section. And the monumental Medical Aspects of Chemical and Biological Warfare, edited by Frederick Sidell, Ernest Takafuji and David Franz (Office of the Surgeon General, US Army, 1997), accords it about two pages out of 721 in a subsection entitled ‘Historical War Gases’.
Back to World War 1
It goes without saying that during and after World War 1 perceptions of chlorine as a combat agent were quite different. Despite having been replaced by much more potent toxic chemicals, belligerents released chlorine gas until the final month of the war. Considering that the first contingents of the American Expeditionary Forces arrived in Europe in June 1917, but saw their first major military engagements in May/June 1918, the US War Department registered and examined 838 ex-service men who had been gassed with chorine (and survived their experience). A closer medical examination of 98 victims to assess the long-term effects of exposure suggests that all US chlorine casualties were affected between July and October 1918. It is interesting to note that Maj. Gen. Harry Gilchrist, Chief of the Chemical Warfare Service, and Philip Matz, Chief of the Medical Research Subdivision of the Veterans’ Administration, devoted half of their medical study, The Residual Effects of Warfare Gases (War Department and US Government Printing Office, 1933), to chlorine, mustard being the other agent of their investigation.
Their description of chlorine remains interesting, because it departs from its utility as a warfare agent, rather than as a public health hazard. The element is almost 2.5 times heavier than air, which means that it will cling to the surface and sink into depressions. At 15° C liquefaction requires 4-5 atmospheres pressure. Upon release at 25° C, one litre of liquid chlorine will yield 434 litres of chlorine gas. Moisture stimulates the element’s chemical action, so the liquid gas must be thoroughly dehydrated for storage in steel cylinders.
Concentration and length of exposure both play a role in the physiological action of chlorine and their effects on humans and animals. The authors noted that ‘a concentration of 1–100,000 of chlorine gas is noticeable, 1–50,000 may cause inconvenience, while a concentration of 1–1,000 may produce death after exposure for five minutes’. (The numbers correspond to 0.01 mg/ml; 0.5 mg/ml and 1mg/ml respectively.) Experimental studies on dogs (carried out to determine the types of lesions various concentrations of chlorine will produce) showed that the animals died within 72 hours from acute effects at concentrations of 2.53 mg/l and higher. These concentrations were labelled as lethal. A small percentage of the animals recovered within a week. A concentration of 1.9–2.53 mg/l increased the recovery rate markedly, whereas dosages below the 1.9 mg/l were rarely fatal. Recovery rates were markedly faster at lower concentrations.
Concentrations required for injury and death are relatively high. For comparison, in the section on mustard (dichlordiethyl sulphide) Gilchrist and Matz deemed this oily compound to be 50 times more toxic than chlorine. It can be deadly in concentrations from 0.006 to 0.2 mg/l, but they considered 0.07 mg/l at an exposure of 30 minutes to be the lethal concentration.
Rewind to March 2013
Syria, just like any other country with a relatively advanced chemical industry, produced chorine in large quantities before the civil war. Readers will recall that early reports of chemical attacks at Khan al-Assal, west of Aleppo, in the middle of March of last year mentioned a strong smell of chlorine. To the east of Aleppo, there was a chlorine production facility (which the Jubhat Al Nusra, a jihadist rebel group ideologically similar to Al Qaeda, reportedly took over in December 2012). However, accounts also mentioned scores of fatalities, which would be inconsistent with a chlorine-filled rocket warhead. I have always been sceptical about those claims, precisely because of the agent’s chemical properties and physiological action. At the time, descriptions did not fit the claimed agents, whichever these might have been.
The need to compress the agent into a liquid has ramifications for delivery: the container must be sufficiently strong to withstand several atmospheres of pressure, and if dropped from an aircraft, sufficiently thin for the skin to break open. It must also be large enough so that a lethal concentration can be built up for a sufficiently long time. Given that humans smell chlorine at very low concentrations, the chances that they will remain at the site of impact are remote. The element is also not colourless; in fact, its name derives from the ancient Greek ‘khloros’, meaning pale green.
The same goes for rocket delivery of the warfare agent. Shells were attempted during World War 1, but this method for chlorine discharge was quickly abandoned in favour of much more potent munition fillings, such as phosgene.
So, it would be good to get more details on the recent incidents and review them in the light of possible chlorine delivery. Please note that I do not deny the possibility of toxic incidents over the past few weeks, but I would just like to see the various facts reconciled with the claimed chain of events. Given that Russian Foreign Minister Sergey Lavrov and French President François Hollande have once again waded into the controversy, politicisation of the ‘truth’ cannot be far away, alas.
Back to where it all started
So, as we reflect on that fateful 22 April in 1915, the sad thought is that chlorine is back, or at least, that people feel that chlorine is back as a possible lethal combat agent.
Allegations fly, but if confirmed, the incidents would be the first acts of chemical warfare committed involving a state party to the CWC. If Syria’s accusation of insurgent use is correct, then the government has every opportunity to demand an investigation from the OPCW and request assistance. If the insurgents’s claim of government use is correct, as non-state actors they cannot request the OPCW anything. However, any state party to the convention can demand an investigation of alleged use by the OPCW, and the Syrian government has no right of refusal (Verification Annex, Part XI). The opposite would be a serious material breach of its treaty obligations and tantamount to an admission of guilt. Or, the states parties can determine that the claims are insufficiently substantiated to warrant an investigation. In which case, it would be nice if they all were to sing the same tune.
So, which way shall the international community have it? The principal long-term casualty of those political games might be the CWC, even though, admittedly, we are still far away from the death knell that 22 April 1915 sounded for the 1899 Hague Declaration (IV, 2) concerning asphyxiating gases.
Several recent reports have suggested that because chlorine or other toxicants, such as riot control agents or incapacitants, are not listed in one of the schedules, they are not covered by the CWC. This is a major error. Any chemical which through its chemical action on life processes can cause death, temporary incapacitation or permanent harm to humans or animals is a chemical weapon, according to Article II of the CWC. This is the default position. There are only four categories of purposes (Art. II, 9), under which a toxic chemical would not be considered a weapon.
A few days ago Robert Serry, the UN Middle East peace envoy, informed the Security Council of increasing reports on chemical weapon (CW) use in the Syrian civil war. He was right of course: in the first four months of 2013 the total number of alleged incidents had already risen by 500% compared to the whole of 2012. Last year there was one claim of CW use with a specific place and time: an attack with an incapacitating agent—sometimes referred to as BZ, other times as (the non-existent) Agent 15 (part of the Iraq invasion lore) near Homs.
Up to 30 April 2013 five such site- and time-specific reports emerged:
- 19 March: The Syrian government accused the insurgents of a chemical attack in Khan al-Assal, Aleppo province. The chlorine (which incredibly turned into sarin over time, and ultimately became bleach) in the rocket killed 16 people according to early reports, a figure that eventually rose to 31. Rebel forces quickly put the blame on the Syrian armed forces. As written in an earlier Arms Control Law contribution, pictures and film footage did not support the allegation.
- 19 March: Rebel allegation of CW attack at Al-Otaybeh, east of Damascus, involving organophosphates. This incident yielded the image of man with foam around the mouth. Foaming is typical of drowning, so the accusation might have had some foundation if the rebels had alleged phosgene use. (Phosgene causes the lungs to be filled with fluid, producing a condition known as ‘dry land drowning’.) However, it is not characteristic of exposure to a nerve agent. A morgue allegedly held six CW fatalities, but not all victims came from Al-Otaybeh.
- 24 March: Rebels allege the use of ‘chemical phosphorus’ bombs at Adra, near Douma. As they did not report burns, the term could have been a misuse for organophosphates. The reports also referred to poisonous gas of some variety producing convulsions, excess saliva, narrow pupils and vomiting.
- 13 April: Two women and two children reportedly died from a chemical agent in a bomb dropped by the Syrian air force in Sheikh Maqsoud, Aleppo District. The death toll, however, varied. Twelve people were also reported to have been injured after contact with the initial victims and responded well to atropine treatment.
- 29 April: Eight people reportedly suffered from vomiting and breathing problems after helicopters had dropped canisters over Saraqeb. One woman later died. One observer presented pictures of canisters similar to one found in Sheikh Maqsoud. While apparently correct, nothing indicates what their contents might have been (some pictures appear to show a bullet exit hole in a canister).
I cannot judge from afar whether these allegations are correct or not. However, I do remain surprised by the lack of visual evidence. In these days of the Internet and when every participant in the Arab uprisings seems to own a camera-equipped smart phone, I cannot find any images or film of victims displaying outward symptoms that correspond with the claimed agent. No images of fatalities; and no images of the areas where the actual attacks took place. Yes, one  picture showed a purported site, but did the scattered animals really die from a CW attack?
More strikingly, the allegations lack density. One would/should expect a multitude of reports with a variety of witnesses recounting a more or less similar incident. One would/should expect them evoke different imageries to express their respective emotions and experiences. These help to reconstruct a testable reality, even from afar. For instance, based on the many television reports in the immediate aftermath of the chemical attacks against Halabja in March 1988—internet and mobile phone prehistory!—I was able to sketch a map of the affected area. The layout later proved to be remarkably similar to the drawing in the report by experts from the Belgian-Dutch Médecins sans frontières who were the first foreigners to reach the town. (As I had no sense of distance, dimensions did differ.) If I read that the US State Department is working behind the scenes to identify medical professionals with proof of CW use and planning to move them out of Syria to meet with UN investigators in Turkey, then I really begin to wonder how scant all other evidence now available to governments must be.
Let’s get serious about chemical weapons in Syria
Based on materials available so far, I continue to find it difficult to give any credence to the CW allegations. The claims do not match reported symptoms. There is no evidence-based back-up of specific allegations from different (including government) sources. Nobody has offered serious refutation of plausible alternative explanations for the described phenomena.
With the passage of time even the narrative has changed: a Midas touch has turned chlorine to sarin, the golden accusation of evil (think Saddam; think Aum Shinrikyo). Indeed, the allegations have mouldered into amorphous compost fertilising calls for humanitarian or military intervention, arming the insurgents and regime change. Particularly, US President Barack Obama’s drawing of a red line with regard to chemical warfare in August 2012 and the questioning of his willingness to follow up on his threat in the light of more recent allegations have distorted discussion of what is actually happening on the ground. More to the point: all these issues have little bearing on whether CW were used or not. If humanitarian law judges 80,000 dead in the civil war as insufficient to justify foreign military intervention, then why would a few scores of fatalities from (supposed) chemical attacks sway the international community, represented by the UN and other regional security and humanitarian institutions? Is it perhaps that ‘eighty thousand’ already represents a ‘statistic’, while politicians today are desperately looking for a ‘tragedy’?
There are serious indications—no proof—that something is amiss in Syria. That something is poisoning the air, literally and metaphorically. For this reason alone, credible and independent investigation of incidents is overdue by long. We surely do not want another Curveball knocking democracy unconscious. Or do we?
On this day, 22 April at 5 p.m. CET the first major chemical attack in modern warfare began 98 years ago, when German Imperial Forces released between 150–168 tonnes of chlorine gas from almost 6000 cylinders along a 700-metre front near the Belgian town of Ieper.
In a study for SIPRI published in 1997, I summarised the opening of the 2nd Battle of Ypres as follows:
Modern chemical warfare is regarded as having begun on 22 April 1915. On that date German troops opened approximately 6000 cylinders along a 7-km line opposite the French position and released 150–168 tonnes (t) of chlorine gas. Tear-gas (T) shells were also fired into the cloud and at the northern flank, the boundary between French and Belgian troops. Between 24 April and 24 May Germany launched eight more chlorine attacks. However, chemical warfare had not been assimilated into military doctrine, and German troops failed to exploit their strategic surprise. Chemical weapon (CW) attacks in following weeks were fundamentally different as they supported local offensives and thus served tactical purposes. In each case the amount of gas released was much smaller than that employed on 22 April, and crude individual protection against gas enabled Allied soldiers to hold the lines.
Prior to the April 1915 use of a chlorine cloud, gas shells filled with T-stoff (xylyl bromide or benzyl bromide) or a mixture of T-stoff and B-stoff (bromoacetone) had been employed. In addition, as early as 14 February 1915 (i.e., approximately the same period as CW trials on the Eastern front) two soldiers of the Belgian 6th Division had reported ill after a T-shell attack. In March 1915 French troops at Nieuwpoort were shelled with a mixture of T- and B-stoff (T-stoff alone had proved unsatisfactory). In response to the British capture of Hill 60 (approximately 5 km south-east of Ypres), German artillery counter-attacked with T-shells on 18 April and the following days. In the hours before the chlorine attack on 22 April the 45th Algerian Division experienced heavy shelling with high explosive (HE) and T-stoff.
Such attacks continued throughout the Second Battle of Ypres. Although Germany overestimated the impact of T-shells, on 24 April their persistent nature appears to have been exploited for the first time for tactical purposes. Near Lizerne (approximately 10 km north of Ypres) German troops fired 1200 rounds in a wall of gas (gaswand) behind Belgian lines to prevent reinforcements from reaching the front. The park of Boezinge Castle, where Allied troops were concentrated, was attacked in a similar manner.
Just a small thought that almost a century later we are still worrying about the possibility of the use of gas in war.