text: zyklon b zyklon b ( german pronunciation : [ ] ; anglicized / / or 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 ) , 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 a 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 . research at 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 and bruno tesch developed a method of packaging hydrogen cyanide in sealed canisters along with a cautionary eye irritant and adsorbent stabilizers . 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 disinfecting 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 to cyanosil in 1974 . mechanism hydrogen cyanide is a poisonous gas that interferes with cellular respiration . 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 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 accepts 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 milligrams ( 0 . 0025 oz ) of hydrogen cyanide . history 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 ( degesch ) , a state - controlled consortium formed to investigate military use of the chemical . chemists at 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 - ( german gold and silver refinery ; degussa ) became sole owners of degesch in 1922 . there , beginning in 1922 , walter heerdt , bruno tesch , and others worked on packaging hydrogen cyanide in sealed canisters along with a cautionary eye irritant 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 ) dated 20 june 1922 . the german patent office awarded the patent on 27 december 1926 . corporate structure and marketing in 1930 , degussa ceded 42 . 5 per cent ownership of degesch to ig farben and 15 per cent to th . goldschmidt ag , in exchange for the right to market pesticide products of those two companies through degesch . degussa retained managerial control . while degesch owned the rights to the brand name zyklon and the patent on the packaging system , the chemical formula was owned by degussa . gmbh , which was 52 per cent 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 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 elbe river , with heli handling clients to the west and south , and testa those to the east . degesch owned 51 per cent of the shares of heli , and until 1942 owned 55 per cent 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 & prior to 1931 and by american cyanamid from 1931 to 1943 . from 1929 , the united states public health service used zyklon b to disinfect 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 disinfecting ships , warehouses , and trains . by 1943 , sales of zyklon b accounted for 65 per cent of degesch 's sales revenue and 70 per cent of its gross profits . use in the holocaust in early 1942 , zyklon b emerged as the preferred killing tool of nazi germany for use in extermination camps during the holocaust . the chemical claimed the lives of 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 . 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 per cent 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 shelf life of only three months ) . testa conducted for the wehrmacht and 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 of the chemical , and thus they were able to use it without any further training or governmental oversight . rudolf höss , commandant of auschwitz , said that the use of zyklon - b to kill prisoners came about on the initiative of one of his subordinates , ss - hauptsturmführer ( captain ) karl fritzsch , who used the substance to kill some russian pows in late august 1941 in the basement of 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 . 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 , 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 chamber . the 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 . legacy 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 of 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 . degussa sold 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 of the czech republic , under the trade name uragan d2 . uragan means " hurricane " or " cyclone " in czech . 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 provoked protests among jewish groups in the u.s. in 1993 , 1999 , and 2011 . 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 2002 , siemens withdrew its application for an american trademark of the word " zyklon " , which their subsidiary bosch und siemens 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 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 product . " holocaust deniers claim that zyklon b gas was not used in the gas chambers , relying for evidence on the 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 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 . explanatory notes