Chlorine: the gas of war crimes

On 2 August this year I noticed a small piece on the BBC news website about a gas attack in Syria. Accounts of the appalling situation in Syria and new devastating attacks seem to be almost a daily feature in the news. What I found especially depressing about the short item that made the news that day, was the alleged use of chlorine gas. Allegations of chlorine gas attacks have appeared again in the news on 11 August, this time resulting in the deaths of one woman and two children as well as a formal investigation by the UN.

Chlorine, the 17th element in the periodic table, is an industrially important chemical. Among other applications it is used in the dying industry and forms the basis for many household bleaches. But chlorine is perhaps most well known as an addition to swimming pools where, in small quantities, it reacts with the water to form hypochlorous acid that kills bacteria and prevents the growth of algae, resulting in safe, sanitary conditions for swimming.

Chlorine also has a much darker history in conflicts stretching back to the first world war. Its use at Ypres on 22 April 1915 marked a new era in chemical warfare. The possible threat of gas attacks had resulted in a treaty signed in 1899 prohibiting their use. The treaty did not stop the French from launching shells containing a primitive tear gas on German lines in 1914 but their aim had been disruption. The development of chlorine gas attacks were designed to kill. To avoid breaching the words of the treaty, though not the spirit, the pioneer of chemical warfare, Fritz Haber, planned the release of the gas from canisters – no projectiles would be involved.

The theory went that the pale green or yellow gas would be slowly pushed over no-mans-land towards the French lines by the wind. The heavier than air gas would then sink into the trenches. The hope was that the choking fumes would cause panic and chaos. French troops would simply run away and a gap would be left wide open for German troops, wearing gas masks, to advance and gain huge amounts of ground. Yes, there would be casualties, but reluctant German officials unsure of the technology were persuaded into trying Haber’s innovative plan as he claimed it would shorten the war and thereby save countless lives in the long run.

Canisters of chlorine were amassed along a fifteen mile stretch of German lines. When the wind eventually turned in the Germans’ favour (the prevailing wind was from the French trenches towards the German lines) the plan proceeded exactly as Haber had predicted. One hundred French troops died in the attack – a remarkably small number in a conflict that regularly saw the slaughter of thousands. But the Germans failed to capitalise on the gaping breach in French lines. As German troops tentatively advanced behind the gas, they were attacked by Canadian and British troops stationed alongside the French.

In the following months, the Allies also developed methods of deploying chlorine gas and both sides went on to develop even more toxic and devastating chemical agents to unleash on their enemies. Haber’s hopes for shortening the war were hopelessly off the mark. After the first chlorine attack at Ypres, the war would continue to grind on for another three and a half years, and estimates of over a million people are thought to have died as a result of the use of poison gas.

The horrific results of poison gas in warfare have spurred the drafting of various treaties signed since the end of the first world war. Progressive agreements in this area have resulted in the banning of the use of chemical weapons in warfare as well as the production, transportation and stockpiling of these compounds. Sadly this has not brought an end to their use in conflicts.

The use of any chemical weapon is appalling. The indiscriminate nature of poison gas and the harrowing effects produced in the human body seems especially callous and inhumane. Chlorine can attack the body in a number of ways producing devastating chemical burns. A complex series of chemical reactions is involved as chlorine reacts with fats, proteins and other material of the body. Most of the damage is thought to be caused by the reaction with moisture in the body to produce acids. The human body contains a lot of water (we are all between two thirds and three quarters water). Breathing the gas in through the moist areas of the mouth and nose to reach the throat and lungs damages these areas in particular. The eyes can also be corroded. There is no antidote. Only supportive care and treatment of symptoms – supporting breathing, clearing affected areas – is possible. Death can be relatively quick or agonisingly slow, depending on the extent of the damage.

The most recent gas attacks in Aleppo are said to have come in the form of barrel bombs dropped from a helicopter. Medical workers on the ground claim the victims they have encountered show characteristic symptoms of chlorine poisoning. We will have to wait for the UN report for confirmation of what has happened and if chlorine, a relic of a historic and terrible war, really has made an unwelcome appearance in the current conflict in Syria. If the accounts are true then the perpetrators, whoever they may be, have committed a war crime.