Zyklon B

The Poison Used in the Gas Chambers

Zyklon B gas canisters
Containers of Zyklon B (poison gas pellets) and a gas mask found at Majdanek after the liberation of the camp. (Photo courtesy USHMM)

Beginning in September 1941, Zyklon B, the brand name for hydrogen cyanide (HCN), was the poison used to kill at least a million people in gas chambers at Nazi concentration and death camps such as Auschwitz and Majdanek. Unlike the Nazis' earlier methods of mass murder, Zyklon B, which was originally used as a common disinfectant and insecticide, proved to be an efficient and deadly murder weapon during the Holocaust.

What Was Zyklon B?

Zyklon B was an insecticide used in Germany before and during World War II to disinfect ships, barracks, clothing, warehouses, factories, granaries, and more. 

It was produced in crystal form, creating amethyst-blue pellets. Since these Zyklon B pellets turned into a highly poisonous gas (hydrocyanic or prussic acid) when exposed to air, they were stored and transported in hermetically-sealed, metal canisters.

Early Attempts at Mass Killing

By 1941, the Nazis had already decided and attempted to kill Jews on a mass scale, they just had to find the fastest way to accomplish their goal.

After the Nazi invasion of the Soviet Union, Einsatzgruppen (mobile killing squads) followed behind the army in order to round up and murder large numbers of Jews by mass shootings, such as at Babi Yar. It wasn't long before the Nazis decided that shooting was costly, slow, and took too large a mental toll on the killers.

Gas vans were also tried as part of the Euthanasia Program and at the Chelmno Death Camp. This mode of killing used the carbon-monoxide exhaust fumes from trucks to murder Jews who were crammed into the enclosed back area. Stationary gas chambers were also created and had carbon monoxide piped in. These killings took about an hour to complete.

The First Test

Rudolf Höss, the commandant of Auschwitz, and Adolf Eichmann searched for a faster way to kill. They decided to try Zyklon B.

On September 3, 1941, 600 Soviet prisoners of war and 250 Polish prisoners who were no longer able to work were forced into the basement of Block 11 at Auschwitz I, known as the "death block," and Zyklon B was released inside. All died within minutes.

Just days later, the Nazis transformed the large morgue room at Crematorium I in Auschwitz into a gas chamber and made 900 Soviet prisoners of war go inside for "disinfection." Once the prisoners were crammed inside, Zyklon B pellets were released from a hole in the ceiling. Again, all died quickly. 

Zyklon B had proved to be a very effective, very efficient, and very cheap way to kill large numbers of people.

The Gassing Process

With the construction of Auschwitz II (Birkenau), Auschwitz became one of the largest killing centers of the Third Reich. 

As Jewish and other "undesirables" were brought into the camp via train, they underwent a Selektion on the ramp. Those deemed unfit for work were sent directly to the gas chambers. However, the Nazis kept this a secret and told the unsuspecting victims that they had to undress for a bath.

Led to a well-camouflaged gas chamber with fake shower heads, the prisoners were trapped inside when a large door was sealed behind them. Then, an orderly, who wore a mask, opened a vent on the roof of the gas chamber and poured Zyklon B pellets down the shaft. He then closed the vent to seal the gas chamber. 

The Zyklon B pellets turned immediately into a deadly gas. In a panic and gasping for air, prisoners would push, shove, and climb over each other to reach the door. But there was no way out. Within five to 20 minutes (depending on the weather), all inside were dead from suffocation.

After all were dead, the poisonous air was pumped out, a process that took about 15 minutes. Once it was safe to go inside, the door was opened and a special unit of prisoners, known as the Sonderkommando, hosed down the gas chamber and used hooked poles to pry the dead bodies apart.

 

Rings were removed and gold plucked from teeth. The the bodies were sent to the crematoria, where they would be turned into ash.

Who Made Zyklon B for the Gas Chambers?

Zyklon B was made by two German companies: Tesch and Stabenow of Hamburg and Degesch of Dessau. After the war, many blamed these companies for knowingly creating a poison that was used to murder over a million people. The directors of both companies were brought to trial.

Director Bruno Tesch and executive manager Karl Weinbacher (of Tesch and Stabenow) were found guilty and given the death sentence. Both were hung on May 16, 1946.

Dr. Gerhard Peters, the director of Degesch, however, was found guilty only as an accessory to homicide.and given a sentence of five years in prison. After several appeals, Peters was acquitted in 1955.