The Science Behind the Holocaust

On the January 27th, it was the International Holocaust Remembrance Day. According to the Secretary-General of the United Nations, Ban Ki-Moon, “The International Day in memory of the victims of the Holocaust is thus a day on which we must reassert our commitment to human rights”.

The historical investigation of tragical events against humanity, such as the Holocaust, the 1994 Genocide in Rwanda, and the atomic bombs of Hiroshima and Nagasaki, can teach us important lessons. One of these lessons is how science can be used to kill thousands, or even millions of people. When I was a child I was told by my mother that “science is supposed to help human lives”. However, in this article, I intend to explain about some scientific innovations that were used against innocent human lives during the World War 2 and the Holocaust. I will focus on the methods of execution including gas chambers and the Nazi medical experiments. The evidence regarding these executions are based on personal essays and reports of the Nuremberg trials.


Gas Chambers

According to the Death Penalty Information Center, “A gas chamber is an apparatus for killing humans or animals with gas, consisting of a sealed chamber into which a poisonous or asphyxiant gas is introduced.” The most commonly used gases are cyanide gas (HCN) and carbon monoxide (CO).

In 1924, a more “humane way” of executing prisoners was introduced in Nevada: the application of cyanide gas (HCN). Gee Jon, a Chinese man sentenced to death, was the first person executed by this mortal gas.


In the gas chamber, the inmate is bound to a seat in a sealed chamber. Under the chair, there is a bucket of sulfuric acid (H2SO4). A long stethoscope is usually attached to the person so that a physician outside the chamber can enunciate the victim’s death. Once all the team members have left the room, the room is sealed. The officer warns the executioner, who releases crystals of sodium cyanide (NaCN) into the bucket.

The chemical reaction that takes place is: H2SO4 + 2 NaCN —> Na2SO4 + 2 HCN, which generates the cyanide gas.

Then, the inmate is informed to breathe intensely to accelerate the killing process. But most of them struggle to hold their breath in order to avoid the inhalation of the gas. Therefore, the prisoner doesn’t lose mindfulness rapidly (Weisberg, 1991).


In order to understand how the gas chambers worked during the Holocaust and also in the 20s, it’s essential to know some of the properties of cyanide gas. Hydrogen cyanide (HCN) is a colorless, extremely poisonous inorganic compound. It is a very volatile liquid, since its boiling temperature is only 25.6 °C, which is slightly above room temperature. This contributes to speed up the victim’s inhalation process. HCN has an imperceptible bitter odor that some people are incapable to detect. Due to its volatility, it has been used as a poison to kill rats, whales, and human beings.

In the human body, cyanide ions (CN-) interfere with iron-containing respiratory enzymes. If the cyanide concentration in the body is too large, its molecules eventually bind to the enzyme’s cytochrome oxidase, which is related to red blood cells. Consequently, there is a deprivation of oxygen to the body’s cells. So death happens due to a lack of oxygen, which is essential for producing energy.

Nazi Human Experimentation

According to the Nuremberg Trials, several experiments were made on human beings. I selected the top 5 experiments that I considered the most interesting, from a scientific viewpoint. The name of each experiment will be followed by the goals that the scientists were willing to achieve (beyond eventually killing the victim).

  • Experiments on twins: to show the similarities and differences in the genetics of twins and to see if the human body can be artificially manipulated;
  • Bone, muscle, and nerve transplantation experiments: to study bone, muscle and nerve regeneration from one individual to other;
  • Freezing experiments: to discover means to prevent and treat hypothermia;
  • Sea water experiments: to study several methods to make sea water drinkable
  • High altitude experiments (using low-pressure chambers): to determine the maximum altitude from which crews of damaged aircraft could parachute to safety.

By looking at these experiments’ goals, one could claim that there were several strategic aims beyond just killing people, since most of their outcomes would facilitate:

  1. The survival of Axis military personnel;
  2. The development and testing of medicines and treatment methods for injuries and illnesses, which German military and occupation personnel had to deal with;
  3. The advance of racial and ideological tenets for the Nazi worldview.

For me, there are several lessons to take from the Holocaust in order to ensure that similar events will never happen again. One of the important things to keep in mind about this period of mass killings is that science can be used for or against human lives. I hope that science will never be used again to kill people in such a systematic, harmful and unfair way based on race, ethnicity, religion, and nationality. I hope that science will be able to improve and save people’s lives as well as make them healthier and happier.


Maybe it’s a utopia, but I will try. Join me! 🙂


Written, with fervor, by Rodrigo Ferreira

Edited by Carlos Sevilla