The CODOH Revisionist Forum

Carbon Monoxide (CO) for Delousing/Disinfestation: A Documented Historical Use

Overview

This research compiles primary and secondary sources documenting the historical use of carbon monoxide (CO) for delousing and disinfestation purposes, with particular focus on German-occupied Warsaw in 1940. It also includes the contemporaneous scientific evidence regarding CO's efficacy against insects (lice), and the broader German fumigation context in which CO was employed.


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1. The Warsaw Hygiene Institute's Approval of CO for Delousing (September 1940)

The principal source documenting the use of CO for delousing/disinfestation in Warsaw is historian Paul Weindling's Epidemics and Genocide in Eastern Europe, 1890–1945 (Oxford University Press, 2000), p. 277:

"By September 1940 Warsaw had twenty new delousing stations with a capacity of 7,000 persons per day. The Hygiene Institute (once the centre of Rajchman's internationalist activities but now under German direction) approved the use of various chemicals and gases, including carbon monoxide and sulphur compounds after rooms were sealed. While Wohlrab regarded other gases as suitable for disinfecting dwellings, he recommended hydrocyanic acid gases as most effective when used in special gas chambers with good heating and ventilation facilities — this typified German support for Zyklon delousing. For its part, DEGESCH was delighted at the profits in supplying Zyklon for large-scale gassings in occupied territories."

Weindling's footnotes for this passage:

[43] Hagen, 'Krieg', 117.

[44] Bayer Archiv, IG Fremdfirmen DEGUSSA 6.14 Bd 1, Geschäftsbericht der DEGESCH für das Jahr 1939 (dated 16 Apr. 1940); ibid., 1940 (dated 29 May 1941).

Source identification:

• Footnote 43 refers to: W. Hagen, "Krieg, Hunger und Pestilenz in Warschau 1939–1943," Gesundheitswesen und Desinfektion 65/8 (1973): 115–127; 65/9 (1973): 129–143. Wilhelm Hagen (1893–1982) served as Amtsarzt (public health officer) in German-occupied Warsaw from January 1941. This source documents the 20 delousing stations and their capacity.

• Footnote 44 refers to DEGESCH (Deutsche Gesellschaft für Schädlingsbekämpfung mbH) annual business reports for 1939 and 1940, held in the Bayer Archiv (IG Fremdfirmen DEGUSSA collection). These are the sources for the statement that the Hygiene Institute approved CO and sulphur compounds for sealed-room disinfestation. DEGESCH, as the manufacturer and distributor of Zyklon B, tracked competing fumigation methods for commercial reasons.

Book reference: Paul Weindling, Epidemics and Genocide in Eastern Europe, 1890–1945 (Oxford: Oxford University Press, 2000), p. 277.
URL: https://global.oup.com/academic/product ... 0198206910


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2. Rudolf Wohlrab: Typhus Control Methods in the General Government

Weindling identifies Rudolf Wohlrab as "head of the typhus department of the Warsaw Hygiene Institute" (p. 277). Weindling further describes Wohlrab's multi-pronged approach to typhus control (same page):

"Rudolf Wohlrab, head of the typhus department of the Warsaw Hygiene Institute, supported in May 1940 an elaborate system of medical screening, hygiene squads, registration, isolation, and disinfection of the sick and of their housing. He prescribed warm showers with cuprex and cevadilla seed preparations, petroleum soaps, and prepared chalk for the disinfection of human bodies."

Weindling's footnote:

[42] R. Wohlrab, 'Flecktyphusbekämpfung im Generalgouvernement. Vortrag gehalten vor der Academia Real, Madrid und der Universität Valladolid', MMW 89/22 (29 May 1942), 483–8.

Full citation: Rudolf Wohlrab, "Flecktyphusbekämpfung im Generalgouvernement. Vortrag gehalten vor der Academia Real, Madrid und der Universität Valladolid," Münchener Medizinische Wochenschrift 89, no. 22 (29 May 1942): 483–488.

The structure of Weindling's passage indicates that Wohlrab drew a distinction between:

• Dwelling/room disinfection — using CO, sulphur compounds, and "other gases" in sealed rooms (i.e., fumigating apartments/houses where typhus patients lived)
• Dedicated delousing gas chambers — using HCN/Zyklon B with proper heating and ventilation for clothing delousing

Both fell under the broad umbrella of "delousing" or "disinfestation" in the anti-typhus campaign.


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3. The Nocht-Giemsa Method: CO as an Established German Fumigation Technology

CO was a well-established fumigation agent in German hygiene practice prior to WWII, through the Nocht-Giemsa method, developed before WWI by Professors Bernhard Nocht and Gustav Giemsa. The Holocaust Encyclopedia describes this method:

"Already before World War One, the German medical professors Bernhard Nocht and Gustav Giemsa developed a fumigation method using carbon monoxide produced by a producer-gas generator. This device burned wood, coal or coke with limited amounts of oxygen, thus producing a gas that contained high amounts of carbon monoxide (CO). Since insects are not sensitive to carbon monoxide, this method is only suitable to kill warm-blooded pests, such as mice and rats. Before, during and after World War One, it was a very common method to combat mice and rats in freight ships."

The same source also notes that CO was listed among DEGESCH's approved fumigation methods:

"Among the various methods used were hot steam, hot air, T-Gas, Areginal, Tritox, carbon monoxide produced by producer-gas generators, and Zyklon B."

Source: Holocaust Encyclopedia, "Fumigation Gas Chamber," https://holocaustencyclopedia.com/technology/fumigation-gas-chamber/

See also: Holocaust Encyclopedia, "Producer Gas," https://holocaustencyclopedia.com/technology/producer-gas/


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4. CO Used for Building Disinfection at Auschwitz

A parallel use of CO for disinfestation purposes is documented at Auschwitz. The German newspaper taz describes how CO was initially used for building disinfection before Zyklon B became the preferred agent:

"Zunächst zur Desinfektion der Gebäude, zur ‚Vergasung' der Opfer diente Kohlenmonoxyd. Der ‚Tötungsvorgang' dauere auf diese Weise jedoch ‚zu lange' und sei ‚zu unsicher', befand Auschwitz-Kommandant Rudolf Höß."

Translation: "Initially, for the disinfection of buildings, as well as for the 'gassing' of victims, carbon monoxide was used. The 'killing process' took 'too long' this way and was 'too unreliable,' found Auschwitz commander Rudolf Höss."

This indicates that CO was used at Auschwitz for building disinfection (i.e., fumigating buildings as part of anti-typhus efforts) — a direct parallel to the Warsaw use described by Weindling.

Source: "Zyklon B – Geschichte eines Giftgases," taz, https://taz.de/Zyklon-B--Geschichte-eines-Giftgases/!1467613/


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5. Scientific Evidence: CO Is Not Toxic to Lice (1920)

A study conducted at American University by the U.S. Bureau of Entomology (U.S. Department of Agriculture) in cooperation with the Chemical Warfare Service tested CO against a variety of insects, including body lice (Pediculus corporis). The study found:

"Carbon monoxid also proved to be nontoxic to insects at a concentration of 3 per cent and an exposure for two hours. The same varieties of insects were used as in the preceding tests."

And in the summary:

"Carbon monoxid in concentrations up to 3 per cent and for exposures of two hours is not toxic to insects."

The list of insects tested explicitly included "Lice, Body (Pediculus corporis Deg.)."

The reason CO is ineffective against insects is physiological: insects respire through a tracheal system rather than hemoglobin-based oxygen transport, so CO — which kills by binding to hemoglobin — has little effect on them. This finding was published in 1920 and was available in the international scientific literature prior to the events in Warsaw.

However, there is no evidence that this finding was known to or considered by the medical officials making decisions about typhus control in Warsaw in 1940. The Neifert et al. study was a U.S. Bureau of Entomology publication, not part of the German medical or hygiene literature per se. Wohlrab was a medical doctor and typhus specialist, not an entomologist or fumigation engineer. The specific entomological finding that insects are insensitive to CO may not have been part of the general knowledge base of medical practitioners making delousing decisions. The intuitive assumption — that a gas known to be lethal to humans and animals would also be lethal to lice — could have been a natural one, even though it is incorrect.

Full citation: Ira Edward Neifert et al., Experiments on the Toxic Action of Certain Gases on Insects, Seeds, and Fungi (Washington, D.C.: U.S. Department of Agriculture, Bureau of Entomology, 1920).
URL: https://doi.org/10.5962/bhl.title.108416


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6. Summary of Sources

Code: Select all

| # | Source                                                                                                                          | What it documents                                                                                                                                                      | URL                                                                                                      |
| - | ------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- |
| 1 | Paul Weindling, Epidemics and Genocide in Eastern Europe, 1890–1945 (Oxford UP, 2000), p. 277, fns. 42–44                       | Warsaw Hygiene Institute approved CO for delousing/disinfestation in sealed rooms, September 1940; sourced to Hagen (1973) and DEGESCH business reports (Bayer Archiv) | https://global.oup.com/academic/product/epidemics-and-genocide-in-eastern-europe-1890-1945-9780198206910 |
| 2 | Rudolf Wohlrab, MMW 89/22 (29 May 1942): 483–488                                                                                | Typhus control methods in the General Government, including dwelling disinfection with gases and clothing delousing with HCN/Zyklon in dedicated gas chambers          | (Print journal; no online URL located)                                                                   |
| 3 | W. Hagen, Gesundheitswesen und Desinfektion 65/8–9 (1973): 115–143                                                              | Retrospective account of the Warsaw delousing stations (20 stations, 7,000 persons/day capacity)                                                                       | (Print journal; no online URL located)                                                                   |
| 4 | Bayer Archiv, IG Fremdfirmen DEGUSSA 6.14 Bd 1, DEGESCH Geschäftsbericht for 1939 (16 Apr. 1940) and 1940 (29 May 1941)         | DEGESCH business records documenting competing fumigation methods approved by the Warsaw Hygiene Institute, including CO                                               | (Archival; not publicly online)                                                                          |
| 5 | Holocaust Encyclopedia, "Fumigation Gas Chamber"                                                                                | Nocht-Giemsa CO fumigation method; CO listed among DEGESCH methods; statement that insects are not sensitive to CO                                                     | https://holocaustencyclopedia.com/technology/fumigation-gas-chamber/                                     |
| 6 | Holocaust Encyclopedia, "Producer Gas"                                                                                          | History of producer-gas generators and CO technology in Germany                                                                                                        | https://holocaustencyclopedia.com/technology/producer-gas/                                               |
| 7 | "Zyklon B – Geschichte eines Giftgases," taz                                                                                    | CO initially used for building disinfection at Auschwitz before Zyklon B became preferred                                                                              | https://taz.de/Zyklon-B--Geschichte-eines-Giftgases/!1467613/                                            |
| 8 | Neifert et al., Experiments on the Toxic Action of Certain Gases on Insects, Seeds, and Fungi (USDA Bureau of Entomology, 1920) | Scientific demonstration that CO is not toxic to insects, including body lice (Pediculus corporis), at 3% concentration for 2 hours                                    | https://doi.org/10.5962/bhl.title.108416                                                                 |

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7. Key Points

1. CO was approved for delousing/disinfestation in Warsaw in September 1940, as documented by Weindling (p. 277), sourced to DEGESCH business reports in the Bayer Archive and to Hagen's 1973 retrospective article.
2. CO was a known fumigation technology in German hygiene practice through the Nocht-Giemsa method (pre-WWI onward), primarily used against rodents.
3. CO was used for building disinfection at Auschwitz before Zyklon B became the preferred agent, per the taz article citing Rudolf Höss.
4. CO was scientifically established as ineffective against lice by 1920 (Neifert et al., USDA Bureau of Entomology). However, there is no evidence that this finding was known to or considered by the medical officials responsible for the Warsaw delousing program. Wohlrab was a medical doctor and typhus specialist, not an entomologist or fumigation engineer. The more likely explanation is that CO was approved based on its general reputation as a lethal fumigant, under the intuitive but incorrect assumption that a gas deadly to humans and animals would also be effective against lice.
5. Wohlrab distinguished between CO/"other gases" for dwelling disinfection and HCN/Zyklon for dedicated gas chamber delousing, suggesting CO was used for sealed-room fumigation of dwellings rather than for clothing delousing in purpose-built chambers.

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