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The Poor Man’s Atomic Bomb: Biowarfare in World War 2

By: Prakriti


‘Biological warfare’ is the intentional use of biological agents such as bacteria, viruses, or any other disease-causing pathogen or vector to incapacitate or kill a human as an act of war. In simpler terms, instead of using guns and cannons, the enemy is killed by infecting them with leprosy and cholera. These ‘weapons’ are highly proficient at mass-killing, as only a few infected people are enough to wipe out populations, making them all the more frightening.

Humans have employed infectious organisms for malicious purposes for centuries. Still, in modern times the first time biological warfare was used was in World War I, or as they called it then, the Great War. German agents reportedly infiltrated the United States and shipped anthrax-infected horses across the Atlantic to the Allied powers. They also attempted to spread the plague in St. Petersburg to weaken Russian resistance.


French troops were the first to employ toxic gas in warfare, using tear gas in 1914. The Germans unleashed chlorine gas against the French forces during the second battle of Ypres in 1915, opening up a hole in the Allied line. However, they underestimated its capabilities and failed to capitalise on the advantage it gave their troops.

Soon, it became apparent that chlorine gas as a weapon was less valuable than previously thought, as its colour and odour made it easy to spot, and if the winds changed direction, the gas would carry back to the same people who released it. Germany’s gas warfare program then moved on to phosgene, which was much more effective and deadlier. Approximately 85% of all gas deaths in World War 1 are estimated to have been caused by phosgene or its derivatives.

The most commonly used gas in World War 1 was bis(2-chloroethyl) sulphide, otherwise known as mustard gas. In the form used in battle, it appeared to have a yellowish colour, lending the gas its name. This gas had a relatively low mortality rate of 2-3%, however, it was capable of causing lifelong chemical burns and respiratory problems.

In 1918, a young Adolf Hitler, serving in the Bavarian army, was partially blinded and temporarily lost his voice due to a British mustard gas attack. In his 1925 autobiography, Mein Kampf, he described this attack: “Towards morning,” Hitler wrote, “I also began to feel pain. It increased every quarter of an hour, and at about seven o’clock; my eyes were scorching.… A few hours later, my eyes were glowing coals, and all was darkness around me.” According to speculation by historians and psychologists, this experience might have been what stopped Hitler, years later, from employing biological warfare with the use of sarin gas in battle.

The horrors of the Great War led to the Geneva Protocol, or the Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or Other Gases, and of Bacteriological Methods of Warfare - a treaty signed to prevent the use of chemical and Biological weapons in international armed conflicts. This treaty covered only the production, storage or transfer of chemical and biological weapons, a loophole used by multiple countries in the following years until treaties signed in 1972 and 1993 covered these aspects.


During the Second World War, multiple countries were found to be violating the Geneva Protocol, most notably Germany, upon which the restrictions imposed by the Treaty of Versailles were also binding. A group of scientists, including Nobel prizewinner Fritz Haber was also discovered to be secretly developing chemical and biological weaponry, including Zyklon A and Zyklon B - the latter used to kill millions of people during the Holocaust.

A German pharmaceutical company, Bayer, was developing a more effective pesticide against beetles. The head of the team, Gerhard Schrader, spent months trying to get the exact formulation for the pesticide, and the idea of adding cyanide, whose previously unknown effects, struck him. However, what resulted was not a bug-killing chemical but was, in fact, a chemical that could kill a person within 20 minutes. When the German military analysed this chemical, they called it ‘Tabun’, inspired by the German word for taboo.

As the army worked on weaponising Tabun, Schrader returned to the drawing board to formulate his pesticide. This time, he ended up with a chemical ten times as toxic as Tabun. He called this compound sarin.

Sarin is a nerve agent and is one of the most toxic chemical warfare agents. It affects the normal functioning of the nervous system by potent and irreversible inhibition of cholinesterase. 1-10 ml of the substance, which is colourless, odourless, and tasteless on the skin, can be fatal.

Once the German military comprehended the full potential of this chemical, they authorised the construction of a factory for its production. High-ranking military officials urged German dictator Adolf Hitler to use it against the enemy.

But Hitler declined.

It would be tough to justify his declination by claiming humanitarian principles since the Nazi concentration camps employed (albeit much less deadly) chemical agents like Zyklon B to exterminate millions of people in the gas chambers. The more logical explanation is that he feared retaliation. On signing the Geneva Protocol, most major powers explicitly reserved the right to use the prohibited bioweapons for retaliatory purposes. This ‘balance of terror’ probably prevented the Nazis from using these deadly weapons.

Another possible explanation could be tactical. A widespread and, thus far, successful German military strategy was the Blitzkrieg, which involved sudden attacks by tanks and bombers followed by swift invading soldiers on foot. If the bombers used sarin gas, the soldiers rushing into the bombed area would have to march through the same contaminated area.

Towards the end of the Second World War, Heinrich Himmler, the leader of the Schutzstaffel, ordered the creation of the Dachau Entomological Institute. Officially, this institute was meant to research protection methods against insect-borne diseases; however, they also secretly pursued research into biological weaponry.

In this institute, scientists studied different types of mosquitoes to determine if they could stay alive during a transportation process from a breeding lab to a drop-off point. Although this research did not amount to much, the Nazis did attempt to attack Italy with a malaria epidemic.

More chilling is the story of Dr Klaus Schilling, a physician at Dachau. Heinrich Himmler gave him a special malaria research station at Dachau’s concentration camp. Schilling was convinced that malaria research on human subjects was entirely safe, so prisoners at Dachau were exposed to infected mosquitoes in cages strapped to their extremities to ensure infection. 300 to 400 of the 1000 prisoners infected were killed during these experiments.


Meanwhile, towards the East, Japan set up a clandestine biological warfare unit called Unit 731, led by physician General Shiro Ishii. He defended his research methodologies by citing the existence of the Geneva Protocol - if these weapons weren’t massively dangerous and practical, they would not have been banned. Ishii also tried justifying himself by noticing that the United States was reluctant to sign the protocol - meaning that they must have been researching biological weapons and were preparing to employ them in war.

Unit 731 was situated in a province in China where Ishii would carry out gruesome human experiments on prisoners of war and civilians. These experiments involved administering pathogens that could cause terrible diseases such as anthrax, botulism, gangrene and the plague to Chinese and Allied prisoners of war. Before these diseases could be weaponised, the Japanese tested the virulence of these pathogens by deliberately infecting and subsequently vivisecting human subjects. Although the process was inhumane, the Japanese could get explicit knowledge about disease progression in the human body by experimenting on live humans. This information helped fortify their biological weapons program both from an offensive and a defensive point of view.

Through these experiments, Ishii determined that the plague bacterium was a more efficient weapon in terms of casualties in proportion to the number of bacteria disseminated. He created a type of clay bomb that could be dropped from aircraft 200-300 metres aboveground and explode without a trace. Each bomb contained 30,000 fleas (Pulex irritans) that were vectors for the Yersinia pestis (plague) bacterium. Apart from these plague bombs, wheat and rice particles covered in Y. pestis were dropped from planes to infect and destroy food supplies in Chinese villages.

The Japanese experiments in China lasted 13 years, ending in 1945 with the end of the Second World War. Since most of the data was destroyed, only an approximate number of victims can be obtained - estimated to be 3,000 to 2,50,000. The plague epidemics caused by the Japanese bombings took another estimated 20,000 Chinese lives.


The Biological Weapons Convention, the first multilateral disarmament treaty banning an entire category of weapons of mass destruction, prohibits the development, acquisition, production, transfer and storage of biological and toxin weapons. These international treaties protect humanity from the dangers of biological war. The human experiments during the Second World War led to the articulation of the Nuremberg Code, a set of ethical principles for human experimentation created during the Nuremberg Trials held after WW2.

In 1988, Hashemi Rafsanjani, the speaker of the Iranian parliament, called chemical and biological weapons the ‘poor man’s atomic bomb’. This description perfectly sums up the danger biological warfare poses to humanity.

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