Zyklon B (US: /ˈzaɪklɒn ˈbiː/ ( listen); German:
[tsykloːn ˈbeː] ( listen); translated Cyclone B) was the
trade name of a cyanide-based pesticide invented in Germany in the
early 1920s. It consisted of hydrogen cyanide (prussic acid), as well
as a cautionary eye irritant and one of several adsorbents such as
diatomaceous earth. The product is infamous for its use by Nazi
Germany during the Holocaust to murder approximately one million
people in gas chambers installed at Auschwitz-Birkenau, Majdanek, and
other extermination camps.
Hydrogen cyanide, a poisonous gas that interferes with cellular
respiration, was first used as a pesticide in
California in the 1880s.
Degesch of Germany led to the development of Zyklon (later
known as Zyklon A), a pesticide which released hydrogen cyanide upon
exposure to water and heat. It was banned after a similar product was
used by Germany as a chemical weapon in World War I. In 1922, Degesch
was purchased by Degussa, where a team of chemists that included
Walter Heerdt (de) and
Bruno Tesch developed a method of
packaging hydrogen cyanide in sealed canisters along with a cautionary
eye irritant and one of several adsorbents such as diatomaceous earth.
The new product was also named Zyklon, but it became known as Zyklon B
to distinguish it from the earlier version. Uses included delousing
clothing and disinfesting ships, warehouses, and trains.
In early 1942,
Zyklon B emerged as the preferred killing tool of Nazi
Germany for use in extermination camps during the Holocaust. Around a
million people were killed using this method, mostly at Auschwitz.
Tesch was executed in 1946 for knowingly selling the product to the SS
for use on humans.
Hydrogen cyanide is now rarely used as a pesticide,
but still has industrial applications. Firms in several countries
continue to produce
Zyklon B under alternative brand names, including
Detia-Degesch, the successor to Degesch, who renamed the product
Cyanosil in 1974.
1 Mechanism of action
3 Corporate structure and marketing
4 Use in the Holocaust
6 See also
7.1 Explanatory notes
8 Further reading
9 External links
Mechanism of action
Hydrogen cyanide is a poisonous gas that interferes with cellular
Cyanide prevents the cell from producing adenosine
triphosphate (ATP) by binding to one of the proteins involved in the
electron transport chain. This protein, cytochrome c oxidase,
contains several subunits and has ligands containing iron groups. The
cyanide component of
Zyklon B can bind at one of these iron groups,
heme a3, forming a more stabilized compound through metal-to-ligand pi
bonding. As a result of the formation of this new iron-cyanide
complex, the electrons that would situate themselves on the heme a3
group can no longer do so. Instead, these electrons destabilize the
compound; thus, the heme group no longer accept them. Consequently,
electron transport is halted, and cells can no longer produce the
energy needed to synthesize ATP. In a human weighing 68 kilograms
(150 lb), death occurs within two minutes of inhaling 70 mg
of hydrogen cyanide.
A fumigation team in New Orleans, 1939. Zyklon canisters are visible.
Hydrogen cyanide, discovered in the late 18th century, was used in the
1880s for the fumigation of citrus trees in California. Its use spread
to other countries for the fumigation of silos, goods wagons, ships,
and mills. Its light weight and rapid dispersal meant its application
had to take place under tents or in enclosed areas. Research by
Fritz Haber of the Kaiser Wilhelm Institute for Physical Chemistry and
Electrochemistry led to the founding in 1919 of Deutsche Gesellschaft
für Schädlingsbekämpfung mbH (Degesch), a state-controlled
consortium formed to investigate military use of the chemical.
Degesch added a cautionary eye irritant to a less volatile
cyanide compound which reacted with water in the presence of heat to
become hydrogen cyanide. The new product was marketed as the pesticide
Zyklon (cyclone). As a similar formula had been used as a weapon by
the Germans during World War I, Zyklon was soon banned.
Deutsche Gold- und Silber-Scheideanstalt (German Gold and Silver
Refinery; Degussa) became sole owners of
Degesch in 1922. There,
beginning in 1922, Walter Heerdt (de), Bruno Tesch, and others
worked on packaging hydrogen cyanide in sealed canisters along with a
cautionary eye irritant[a] and adsorbent stabilizers such as
diatomaceous earth. The new product was also labelled as Zyklon, but
it became known as
Zyklon B to distinguish it from the earlier
version. Heerdt was named the inventor of
Zyklon B in the Degesch
patent application (number DE 438818) dated 20 June 1922. The German
Patent Office awarded the patent on 27 December 1926. Beginning in
Zyklon B was used at U.S. Customs facilities along the
Mexican border to disinfect the clothing of border crossers.
Corporate structure and marketing
A can of
Zyklon B with adsorbent granules and original signed
documents detailing ordering of
Zyklon B as "materials for Jewish
resettlement" (on display at
Auschwitz concentration camp
Auschwitz concentration camp museum)
Degussa ceded 42.5 percent ownership of
Degesch to IG Farben
and 15 percent to Th. Goldschmidt AG, in exchange for the right to
market pesticide products of those two companies through Degesch.
Degussa retained managerial control.
Degesch owned the rights to the brand name Zyklon and the patent
on the packaging system, the chemical formula was owned by
Degussa. Schlempe GmbH, which was 52 percent owned by Degussa,
owned the rights to a process to extract hydrogen cyanide from waste
products of sugar beet processing. This process was performed under
license by two companies, Dessauer Werke and Kaliwerke Kolin, who also
combined the resulting hydrogen cyanide with stabilizer from IG Farben
and a cautionary agent from
Schering AG to form the final product,
which was packaged using equipment, labels, and canisters provided by
Degesch. The finished goods were sent to Degesch, who
forwarded the product to two companies that acted as distributors:
Heerdt-Linger GmbH (Heli) of
Frankfurt and Tesch & Stabenow
(Testa) of Hamburg. Their territory was split along the
with Heli handling clients to the west and south, and Testa those to
Degesch owned 51 percent of the shares of Heli, and
until 1942 owned 55 percent of Testa.
Prior to World War II
Degesch derived most of its
Zyklon B profits
from overseas sales, particularly in the United States, where it was
produced under license by Roessler & Hasslacher prior to 1931 and
American Cyanamid from 1931 to 1943. From 1929, the United
States Public Health Service used
Zyklon B to disinfest freight trains
and clothes of Mexican immigrants entering the United States. Uses
in Germany included delousing clothing (often using a portable sealed
chamber invented by
Degesch in the 1930s) and disinfesting ships,
warehouses, and trains. By 1943, sales of
Zyklon B accounted for
65 percent of Degesch's sales revenue and 70 percent of its gross
Use in the Holocaust
See also: The Holocaust
Empty poison gas canisters found by the Allies at the end of World War
In early 1942,
Zyklon B emerged as the preferred killing tool of Nazi
Germany for use in extermination camps during the Holocaust. The
chemical was used to kill roughly one million people in gas chambers
installed in extermination camps at Auschwitz-Birkenau, Majdanek, and
elsewhere. Most of the victims were Jews, and by far the majority
killed using this method died at Auschwitz.[b]
Zyklon B was
supplied to concentration camps at Mauthausen, Dachau, and Buchenwald
by the distributor Heli, and to Auschwitz and
Majdanek by Testa. Camps
also occasionally bought
Zyklon B directly from the manufacturers.
Of the 729 metric tons of
Zyklon B sold in Germany in 1942–44, 56
metric tons (about 8 percent of domestic sales) were sold to
concentration camps. Auschwitz received 23.8 tons, of which 6 tons
were used for fumigation. The remainder was used in the gas chambers
or lost to spoilage (the product had a stated shelf life of only three
months). Testa conducted fumigations for the
supplied them with Zyklon B. They also offered courses to the SS in
the safe handling and use of the material for fumigation purposes.
In April 1941, the German agriculture and interior ministries
designated the SS as an authorized applier of the chemical, and thus
they were able to use it without any further training or governmental
Rudolf Höss, commandant of Auschwitz, said that the use of Zyklon-B
to kill prisoners came about on the initiative of one of his
Hauptsturmführer (captain) Karl Fritzsch, who used
the substance to kill some Russian POWs in late August 1941 in the
Block 11 in the main camp. The experiment was repeated on
more Russian POWs, with Höss watching, in September. Block 11
proved unsuitable for mass killings, as the basement was difficult to
air out afterwards and the crematorium (Crematorium I, which operated
until July 1942) was some distance away. The site of the killings
was moved to Crematorium I, where more than 700 victims could be
killed at once. By the middle of 1942, the operation was moved to
Auschwitz II–Birkenau, a nearby satellite camp which had been under
construction since October 1941.
The first gas chamber at Auschwitz II–Birkenau was the "red house"
(called Bunker 1 by SS staff), a brick cottage converted to a gassing
facility by tearing out the inside and bricking up the windows. It was
operational by March 1942. A second brick cottage, the "white house"
or Bunker 2, was converted some weeks later. According to
Höss, Bunker 1 held 800 victims and Bunker 2 held 1,200 victims.
These structures were in use for mass killings until early 1943.
At that point, the Nazis decided to greatly increase the gassing
capacity of Birkenau. Crematorium II, originally designed as a
mortuary, with morgues in the basement and ground-level incinerators,
was converted into a killing factory by installing gas-tight doors,
vents for the
Zyklon B to be dropped into the chamber, and ventilation
equipment to remove the gas afterwards.[c] Crematorium III was
built using the same design. Crematoria IV and V, designed from the
start as gassing centers, were also constructed that spring. By June
1943, all four crematoria were operational. Most of the victims were
killed using these four structures.
The Nazis began shipping large numbers of
Jews from all over Europe to
Auschwitz in the middle of 1942. Those who were not selected for work
crews were immediately gassed. The group selected to die, about
three-quarters of the total,[d] included almost all children, women
with small children, all the elderly, and all those who appeared on
brief and superficial inspection by an SS doctor not to be completely
fit. The victims were told they were to undergo delousing and a
shower. They were stripped of their belongings and herded into the gas
Zyklon B was delivered by ambulance to the crematoria by a special
SS bureau known as the Hygienic Institute. The actual delivery of
the gas to the victims was always handled by the SS, on the order of
the supervising SS doctor. After the doors were shut, SS men
dumped in the
Zyklon B pellets through vents in the roof or holes in
the side of the chamber. The victims were dead within 20 minutes.
Johann Kremer, an SS doctor who oversaw gassings, testified that the
"shouting and screaming of the victims could be heard through the
opening and it was clear that they fought for their lives".
Sonderkommandos (special work crews forced to work at the gas
chambers) wearing gas masks then dragged the bodies from the chamber.
The victims' glasses, artificial limbs, jewelry, and hair were
removed, and any dental work was extracted so the gold could be melted
down. If the gas chamber was crowded, which they typically were,
the corpses were found half-squatting, their skin discolored pink with
red and green spots, with some found foaming at their mouths, or
bleeding from their ears. The corpses were burned in the nearby
incinerators, and the ashes were buried, thrown in the river, or used
as fertilizer. With the Soviet
Red Army approaching through
Poland, the last mass gassing at Auschwitz took place on 30 October
1944. In November 1944,
Reichsführer-SS Heinrich Himmler, head of
the SS, ordered gassing operations to cease across the Reich.
Majdanek gas chamber, showing
Prussian blue residue
After World War II ended in 1945,
Bruno Tesch and
Karl Weinbacher of
Tesch & Stabenow were tried in a British military court and
executed for knowingly providing
Zyklon B to the SS for use on
humans. Gerhard Peters, who served as principal operating officer
Degesch and Heli and also held posts in the Nazi government, served
two years eight months in prison as an accessory before being released
due to amendments to the penal code.
Use of hydrogen cyanide as a pesticide or cleaner has been banned or
restricted in some countries. Most hydrogen cyanide is used in
industrial processes, made by companies in Germany, Japan, the
Netherlands and the US.
Degesch resumed production of Zyklon B
after the war. The product was sold as Cyanosil in Germany and Zyklon
in other countries. It was still produced as of 2000.
Degesch to Detia-Freyberg GmbH in 1986. The company is now called
Detia-Degesch. A fumigation product similar to
Zyklon B is also in
production by Lučební závody Draslovka of the Czech Republic, under
the trade name Uragan D2. Uragan means "hurricane" or "cyclone" in
Subsequent use of the word "Zyklon" in trade names has prompted angry
reactions in English-speaking countries. The name "Zyklon" on portable
roller coasters made since 1965 by
Pinfari provoked protests among
Jewish groups in the U.S. in 1993, and 1999. In 2002, British
sportswear and football equipment supplier
Umbro issued an apology and
stopped using the name "Zyklon", which had appeared since 1999 on the
box for one of its trainers, after receiving complaints from the Simon
Wiesenthal Center and the Beth Shalom Holocaust Centre. Also in
Siemens withdrew its application for an American trademark of
the word "Zyklon", which their subsidiary BSH Bosch und Siemens
Hausgeräte had proposed to use for a new line of home appliances in
the United States. (The firm was already using the name in Germany for
one of their vacuum cleaners.) Protests were lodged by the Simon
Wiesenthal Center after the trademark application was reported to BBC
News Online by one of their readers. French company IPC's product
names used "Cyclone" for degreasers and suffix "B" for biodegradable:
"Cyclone B" was renamed "Cyclone Cap Vert" ("green cap") in 2013 after
protests from Jewish groups. A rabbi said the name was
"horrible ignorance at best, and a Guinness record in evil and
cynicism if the company did know the history of the name of its
Holocaust deniers claim that
Zyklon B gas was not used in the gas
chambers, relying for evidence on the discredited research of Fred A.
Leuchter, who found low levels of
Prussian blue in samples of the gas
chamber walls and ceilings. Leuchter attributed its presence to
general delousing of the buildings. Leuchter's negative control, a
sample of gasket material taken from a different camp building, had no
cyanide residue. In 1999, James Roth, the chemist who had analyzed
Leuchter's samples, stated that the test was flawed because the
material that was sent for testing included large chunks, and the
chemical would only be within 10 microns of the surface. The surface
that had been exposed to the chemical was not identified, and the
large size of the specimens meant that any chemical present was
diluted by an undeterminable amount. In 1994, the Institute for
Forensic Research in
Kraków re-examined Leuchter's claim, stating
that formation of
Prussian blue by exposure of bricks to cyanide is
not a highly probable reaction. Using microdiffusion techniques,
they tested 22 samples from the gas chambers and delousing chambers
(as positive controls) and living quarters (as negative controls).
They found cyanide residue in both the delousing chambers and the gas
chambers but none in the living quarters.
^ Cautionary eye irritants used included chloropicrin and cyanogen
^ Soviet officials initially stated that over 4 million people were
Zyklon B at Auschwitz, but this figure was later proven
to be greatly exaggerated.
^ The gas chamber also had to be heated, as the
Zyklon B pellets would
not vaporize into hydrogen cyanide unless the temperature was
27 °C (81 °F) or above.
^ Of the Hungarian
Jews who arrived in the middle of 1944, 85 percent
were killed immediately.
^ a b Nelson & Cox 2000, pp. 668, 670–71, 676.
Cyanide Management Institute.
^ a b Hayes 2004, p. 273.
^ Hayes 2004, pp. 273–274.
^ Hayes 2004, p. 274.
^ Christianson 2010, p. 95.
^ Hayes 2004, pp. 274–275.
^ Heerdt 1926.
^ Burnett 2006.
^ Hayes 2004, pp. 278–279.
^ Hayes 2004, p. 280.
^ Hayes 2004, p. 275.
^ Hayes 2004, pp. 275–276.
^ Christianson 2010, p. 165.
^ Christianson 2010, p. 166.
^ Hayes 2004, Chart, p.357.
^ Christianson 2010, pp. 10, 92, 98.
^ Christianson 2010, p. 92.
^ a b Hayes 2004, p. 281.
^ Longerich 2010, pp. 281–282.
^ Hayes 2004, pp. 2, 272.
^ a b c Piper 1994, p. 161.
^ Hayes 2004, p. 272.
^ Steinbacher 2005, pp. 132–133.
^ Hayes 2004, pp. 288–289.
^ Hayes 2004, p. 296.
^ Hayes 2004, pp. 294–297, chpt.
Degesch and Zyklon
B. »The SS learned in 1944 that the expiration dates on the
Zyklon tins were not hard and fast. All in all, it seems reasonable to
assume that the SS over- rather than underdosed...« (Peter
^ Hayes 2004, p. 283.
^ Hayes 2004, p. 284.
^ Browning 2004, pp. 526–527.
^ a b c Pressac & Pelt 1994, p. 209.
^ Piper 1994, pp. 158–159.
^ Rees 2005, pp. 96–97, 101.
^ a b c Piper 1994, p. 162.
^ Steinbacher 2005, p. 98.
^ Steinbacher 2005, pp. 100–101.
^ Rees 2005, pp. 168–169.
^ Pressac & Pelt 1994, p. 214.
^ Steinbacher 2005, p. 109.
^ Levy 2006, pp. 235–237.
^ a b c Piper 1994, p. 170.
^ Piper 1994, p. 163.
^ a b Piper 1994, p. 171.
^ Piper 1994, p. 174.
^ Steinbacher 2005, pp. 123–124.
^ Shirer 1960, p. 972.
^ Hayes 2004, pp. 297–298.
^ United Nations 2002, pp. 545, 171, 438.
^ Dzombak et al. 2005, p. 42.
^ United Nations 2002, p. 545.
^ BFR 2000.
^ Hayes 2004, p. 300.
^ Lučební závody Draslovka.
^ New York Times 1993.
^ Katz 1999.
^ BBC News & August 2002.
^ BBC News & September 2002.
^ Piérot 2013.
The Jewish Press
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^ Harmon & Stein 1994.
^ Mr. Death: Transcript 1999.
^ Bailer-Gallanda 1991.
^ Markiewicz, Gubala & Labedz 1994.
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