Syria chlorine attack claims: what this chemical is and how it became a weapon

Use as a weapon
Fritz Haber (1868-1934) knew about the toxicity of chlorine when he chose it as his agent of warfare in 1915. He had already come up with the Haber-Bosch process, patented in 1910, for the fixation of nitrogen as ammonia, which won him the 1918 Nobel Prize in chemistry. This made the manufacture of artificial fertilizers possible and the survival of millions of people today depends on it.

But it also enabled the mass production of nitric acid, source of the explosives that Germany used in the First World War. Haber was an intensely patriotic German Jew. He was head of the chemistry section in the Ministry of War, coordinating the production of ammonia needed to fight the war. He was also in charge of chemical warfare, choosing chlorine gas as the agent.

Haber supervised the installation of the first chlorine gas cylinders in the trenches on the Western front, near Ypres. He and the specialist troops waited for the wind to blow from the east towards the Allied trenches and launched the first gas attack on 22 April 1915. As clouds of chlorine drifted towards the Allies, panic set in. It was no good diving into a trench, as the dense chlorine was heavier than air and poured in. Of the 15,000 or more casualties, 5,000 soldiers were killed.

Haber’s story ended tragically in several ways. He returned home to a celebration of the success of the attack on 1 May but that night his wife Clara committed suicide after an argument — possibly over the morality of what he was doing. A few years later he developed a system for getting rid of insect pests, using hydrogen cyanide. It became known as the Zyklon system. A derivative pesticide, Zyklon B, was used to exterminate millions in Nazi concentration camps, where many of Haber’s close relatives died.

Gas masks were developed to protect against chlorine attacks and other chemical warfare agents were developed. But chlorine remains the simplest chemical weapon and reappeared on the battlefield during the Iraq War and allegedly now in Syria. In the Second World War, both sides of the conflict knew that the other side had weaponized chlorine and refrained from using it. Today in Syria, it sadly appears this may not have been the case.

Simon Cotton is Senior Lecturer in Chemistry, University of Birmingham. This article is published courtesy of The Conversation (under Creative Commons-Attribution / No derivative).