Like the other killing centers, Auschwitz at first used carbon monoxide. But on or about September 3, 1941, its killers began to try out another gas. An SS officer took cans of Zyklon-B from the camp’s supply room and ordered staff to use it against 600 Soviet prisoners of war and 250 or so other prisoners—mostly Poles—who had been selected from the camp’s infirmary. The victims were crammed into basement cells of Building 11 (“The Bunker”), which served as the camp’s punishment block. Soldiers dumped Zyklon into the cells and closed the windows and sealed them with sand to prevent leakage. Then they waited to see what would happen. After the gas had cleared, they discovered that some had survived, so they repeated the procedure. This time they found everyone dead.
The SS had begun to divert large quantities of the insecticide, planning to murder millions of prisoners. Medical imperatives and the involvement of physicians in the “euthanasia” process had been replaced by sheer brutality, trickery, and the treatment of human beings as vermin in an attempt to exterminate masses of people.
The Zyklon-B used in the gas chambers consisted of hydrogen cyanide and a warning agent impregnated into a solid support.12 Instructions for its use, published by one of its German manufacturers, DEGESCH, mentioned three possible solid supports, claiming, “Wood fibre discs (discoids), a reddish brown granular mass (diagriess—Dia gravel) or small blue cubes (Erko) are used as carriers.”13 The most common solid carrier of Zyklon-B used at Auschwitz-Birkenau consisted of the small, chalky, grayish-blue cubes or pellets (Erko).14
In selecting Prussic acid, the Nazis chose one of their own German creations. Hydrocyanic acid had a long history of being used for delousing and fumigation in Germany and around the world, and the German military was already using it to fumigate barracks in the concentration camps, just as American Cyanamid was using it to fumigate American military barracks. The United States Public Health Service had utilized large quantities of Zyklon for pest removal. For fifteen years hydrocyanic acid had also been used throughout America in legal executions, which had been written up in countless journals and apparently widely accepted as causing a quick and painless death.15 But never before had it been used for mass murder.
For years Holocaust researchers wondered about the particular form of Zyklon-B that was used in the death camps, and particularly about what kind of solid support was used. In July 2000 a sample of Zyklon-B pellets from Auschwitz was obtained from Director Jerzy Wróblewski of the Panstwowe Museum Auschwitz-Birkenau in Oświęcim, Poland. Harry W. Mazal of the Holocaust History Project conducted physical and chemical analysis in an effort to identify the substrate employed for Zyklon-B that was designated for murdering prisoners there. The sample Wróblewski provided and samples of two other materials—diatomaceous earth and Drierite (anhydrous calcium sulfate)—were examined using a scanning electron microscope, and they produced dramatic results. The sample containing a Zyklon-B pellet showed a microcrystalline structure with orthorhombic crystals that were approximately 1.5 micrometers wide and 7 to 15 micrometers long. The pore size was several micrometers in diameter.
Further analysis was conducted using an energy dispersive X-ray analysis (EDX) accessory mounted on the scanning electron microscope. This method would permit accurate qualitative and semi-quantitative elemental analysis of inorganic materials in the sample. The Zyklon-B sample showed clear peaks for calcium, oxygen, and sulfur, as well as some very minor traces of barium and aluminum. It was calcium sulfate, but not soluble anhydride.
A comparison between the EDX analysis of the Zyklon-B pellet and a sample of calcium sulfate clearly showed they were identical in composition. The analyst concluded that the Zyklon-B sample was “either the natural form of anhydrous calcium sulfate, also known as the mineral anhydrite, or, equally likely, the insoluble anhydrite resulting from heating gypsum at temperatures above 650 degrees centigrade.”16 Anhydrite is a colorless, white, gray, blue, or lilac mineral of anhydrous calcium sulfate, CaSO4, occurring as layers in gypsum deposits.
It is unclear who manufactured the anhydrite and whether they knew the use to which it was being put in the camps. DEGESCH had licensed two German companies—Tesch und Stabenow (Testa) of Hamburg and Heerdt-Lingler (Heli)—along with American Cyanamid of the United States to manufacture and distribute Zyklon-B. The Zyklon-B crystals that killed prisoners at Auschwitz-Birkenau were allegedly furnished by Tesch und Stabenow and DEGESCH. Tesch und Stabenow supplied two tons of the cyanide crystals a month and DEGESCH provided three quarters of a ton, according to the bills of lading that were presented into evidence at the war crimes trials.
Hydrogen cyanide had been absorbed into the substrate and placed in sealed steel cans. At the time of packaging the substrate and the gas had been combined with a stabilizing chemical that made it considerably more manageable and less volatile than other forms of hydrocyanic acid. Unlike the potassium cyanide used in American gassings, the Zyklon-B did not require immersion in sulfuric acid and water to vaporize. When the Zyklon tins were unsealed and their contents dumped into an enclosed and heated chamber crowded with naked human beings, the pellets simply released deadly hydrocyanic acid gas into the atmosphere, thereby killing those in the gas chamber.
The Nazis’ first use of Zyklon-B at Auschwitz appeared to have worked so well that it became the gas of choice for mass extermination. Systematic gassing of Jews began shortly thereafter.
A former Auschwitz gas chamber officer coldly described how the poison was used. “The disinfectors were at work,” he said. “One of them was SS-Unterscharführer Teuer, decorated with the Cross of War Merit. With a chisel and a hammer they opened a few innocuous-looking tins which bore the inscription ‘Cyclon, to be used against vermin. Attention, poison! to be opened by trained personnel only!’. The tins were filled to the brim with blue granules the size of peas. Immediately after opening the tins, their contents was thrown into the holes which were then quickly covered.”17 Rudolf Höss, SS-Kommandant of Auschwitz, later testified, “The gassing was carried out in the detention cells of Block II. Protected by a gas mask, I watched the killing myself. In the crowded cells, death came instantaneously the moment Zyklon-B was thrown in. A short, almost smothered cry, and it was all over.”18
At another gassing, in autumn 1941, an officer ordered the institution’s registrar of new arrivals (Hans Stark) to pour Zyklon-B into the roof opening because only one medical orderly had shown up. “During a gassing Zyklon-B had to be poured through both openings of the gas-chamber room at the same time.” Stark later recalled:
This gassing was also a transport of 200–250 Jews, once again men, women and children. As the Zyklon-B… was in granular form, it trickled down over the people as it was being poured in. They then started to cry out terribly for they now knew what was happening to them. I did not look through the opening because it had to be closed as soon as the Zyklon-B had been poured in. After a few minutes there was silence. After some time had passed—it may have been ten to fifteen minutes—the gas chamber was opened. The dead lay higgledy-piggledy all over the place. It was a dreadful sight.19