Document NI-9912 Disproves Nuremberg Accusations on Zyklon B-Faurisson

…This document describes the properties of Zyklon, its risk of explosion, its toxicity… To produce the desired effect it must be spread thinly on paper mats; none of it is to be lost anywhere: all will be recovered in due course. It will take from six to thirty-two hours to kill the pests (sixteen hours on average). Then will come the most critical moment, that of aeration…

Robert FAURISSON                                                                             January 1, 1977

Translation of Nuremberg document NI-9912

Document NI-9912 reduces to naught all the supposed “witnesses’ accounts”, without exception, on the use of Zyklon B to kill human beings.

Remarks on the document

Cyclon BIt comes from the archives of the Nuremberg trials. It was registered by the Americans at a late date: August 21, 1947, in the “NI” category (Nuremberg, Industrialists). It was taken from the archives of the Degesch company and listed under four headings, among which that of “Atrocities” (sic).

The original, in the form of four large pages to be posted on walls, was a notice that must have been distributed in a great many copies; the specimen translated here was issued by the Prague Health Authority, doubtless in the midst of the war. The contents show that its purpose was to convey instructions for the use of Zyklon (prussic or hydrocyanic acid) to destroy vermin in buildings which could be either civil or military (apartment blocks, barracks, etc.). The document fittingly reminds us of a truth learnt from experience: of all deadly weapons, gas will probably long remain the most unwieldy; when it kills, it kills so well that it can be fatal to the killer who decides to use it. If it is quite easy to kill with prussic acid, it is also quite difficult to kill anyone nearby without running terrible risks oneself.

This document describes the properties of Zyklon, its risk of explosion, its toxicity. Only persons possessing a certificate obtained after special training may use the product. A gassing’s planning and preparations call for measures and tasks requiring several hours, possibly days. Then comes the operation itself. Among many details we note here that Zyklon is not to be poured out into a pile or through the air. To produce the desired effect it must be spread thinly on paper mats; none of it is to be lost anywhere: all will be recovered in due course. It will take from six to thirty-two hours to kill the pests (sixteen hours on average). Then will come the most critical moment, that of aeration. The text says: “Aeration presents the greatest danger for both participants and non-participants. It is therefore necessary to proceed with particular caution, and always wearing a gasmask.” This aeration will have to last “at least twenty hours”. Sentries, during all that time and even afterwards, must remain near the building. To make sure that no gas remains, the specialists, again in gasmasks, enter the premises with a strip of paper that will indicate the presence of any residual gas. Twenty hours previously, the simple opening of doors and windows, as well as easy tasks of moving “planking and sealing items” (an effort amounting to nothing compared with the dragging away of hundreds even thousands of corpses) had presented a certain danger – inherent in a possible acceleration of the breathing – since, after the aeration of each floor, the team had had to go outside, remove their masks and breathe fresh air for at least ten minutes. All the rest is in a similar vein and I leave it to the reader to discover in each line of this document how absurd by comparison the stories of our false witnesses are. [Author’s note]


Document NI-9912


Guidelines for the Use of Prussic Acid (Zyklon)

For Destruction of Vermin (Disinfestation)

  1. Properties of Prussic acid:

Prussic acid is a gas that is released by evaporation.

Boiling point: 26° C.

Freezing point: -15° C.

Specific weight: 0.69.

Vapour density: 0.97 (air = 1.0).

Liquid form evaporates easily.

Liquid form: clear and colourless as water.

Smell: unique, bitter-sweet.

Powerful ability to penetrate.

Prussic acid is water-soluble.

Danger of explosion: 75 g. Prussic acid in 1 cbm. air. (Normal application is ca. 8 – 10 g. per cbm., so not explosive). Prussic acid should not be brought into contact with open fire, glowing metal wire, and so forth. It burns slowly and loses its potency completely. (It produces carbonic acid, water and azote.)

Toxicity to warm-blooded animals:

Prussic acid emits practically no warning to the senses, therefore it should be considered highly poisonous and highly dangerous. Prussic acid is one of the most powerful poisons. 1 mg. per kg.-body weight is enough to kill a man. Children and women are usually more sensitive than men. A very small quantity of Prussic acid does not harm men, even with constant breathing. Birds and fish are very sensitive to Prussic acid.

Toxicity to insects:

The effect of prussic acid on insects depends less on temperature than is the case with other gases; that is, it even works at cold temperatures (even down to -5° C). For many species, particularly bedbugs and lice, the eggs are more sensitive than the imagos.

Toxicity to plants:

The degree of toxicity depends on the plants’ state of development. Plants with hard leaves are less sensitive than those with soft leaves. Mould and dry rot are not killed by prussic acid.

Prussic acid does not kill bacteria.

  1. Forms in which Prussic acid is used:

Zyklon is a mixture of Prussic acid and an irritating agent absorbed in a substrate. The substrate may be wood disks, a granular red-brown material (“Diagriess”) or small blue cubes (“Erco”).

The irritating agent is used as a warning device, and offers an additional advantage in that it stimulates the breathing of insects. Release of prussic acid and the irritating agent by simple evaporation. Zyklon will keep for 3 months. Use damaged cans first. Always use up the contents of a can completely. Liquid prussic acid damages polish, varnish, paints, etc. – gaseous prussic acid does not. The toxicity of prussic acid is not affected by the irritating agent, but the danger is considerably reduced.

Zyklon can be rendered harmless by burning.

III. Possibilities of poisoning:

  1. Slight poisoning:

Dizziness, headache, vomiting, discomfort etc. These symptoms will disappear if one quickly goes out into fresh air. Alcohol reduces the resistance to prussic acid gassing – do not drink alcoholic beverages before gassing.

Administer: 1 tablet of Cardiazol or Veriazol to prevent heart trouble, another tablet 2 to 3 hours later if need be.

  1. Severe poisoning:

The victim collapses suddenly and is unconscious. First aid: fresh air, remove gas mask, loosen clothing, assist breathing. Lobelin intramuscular 0.01 g. Camphor injections are forbidden.

  1. Poisoning through the skin:

Symptoms as with 1. Treatment also the same.

  1. Stomach poisoning

to be treated with:

Lobelin 0.01 g. intramuscular

iron sulphate vitriol

calcinated magnesia.


  1. Protection against the gas:

When gassing with Zyklon use only special filters, such as filter cartridge “J” (blue-brown) made by Auergesellschaft of Berlin, or Dragerwerke of Lübeck.

If gas gets through the mask, leave the building immediately and change filters, after having also checked the mask’s sealing and adjustment. The filter cartridge is exhausted when gas gets through the mask. With filter cartridge “J” go into the open air for about 2 minutes, so that moisture from the breath can build up in the filter cartridge. –

The filter must never be changed in a gas-filled room.

  1. Personnel:

For every disinfestation, a disinfestation team will be used, consisting of at least 2 men. The gassing chief is responsible for the gassing. His duties include, in particular, inspection, aeration, giving the all-clear and safety measures. The chief should appoint a deputy in case he is absent. The chief’s orders must be obeyed without hesitation.

Untrained personnel or trained personnel without a certificate must not be used for gassing operations. Such persons also must not be allowed to enter a room filled with gas. The chief must know where his personnel are at all times. All personnel must be able to prove at all times that they possess official authorisation to use prussic acid for disinfestation.

These guidelines must be followed exactly in all cases.

  1. Equipment:

Each man must have with him at all times:

  1. His own gas mask.
  2. At least 2 special packets for use against Zyklon prussic acid.
  3. The manual “First Aid for Prussic Acid Victims”.
  4. A copy of the work order.
  5. Authorisation certificate.

Every disinfestation team must have with it at all times:

  1. At least 3 additional special packets.
  2. 1 residual gas detector.
  3. 1 Lobelin injection device.
  4. Lobelin, 0.01 g. ampules.
  5. (Cardiazol), Veriazol tablets.
  6. 1 prybar or spike-hammer to open Zyklon cans.
  7. Warning posters of the prescribed kind.
  8. Sealing material.
  9. Paper sheets on which to lay out Zyklon.
  10. An electric torch.

All equipment must be kept clean and in working condition. Damage to equipment must be repaired immediately.

VII. Planning a gassing:

  1. Will the gassing work?
  2. a) Type and situation of the building.
  3. b) Nature and condition of the roof.
  4. c) Nature and condition of the windows.
  5. d) Presence of heating shafts, air shafts, holes in the wall, etc.
  6. Determine the kind of pests to be destroyed.
  7. Calculate the volume of the space. (Do not rely on plans, make own measurements. Measure only exterior dimensions, inclusive of masonry.)
  8. Prepare the occupants (Remove domestic animals, plants, food, undeveloped photographic plates, beverages and tobacco, gas mask filters).
  9. Determine openings difficult to seal. (Air shafts, drains, large openings with wooden planking, roofs).
  10. Determine necessary safety measures. (Guards, work team for sealing).
  11. Set the date for the operation and the time needed for evacuation.
  12. Make plans for the safety of the surrounding area, if necessary.
  13. Notify the authorities.

VIII. Preparation for a gassing:

  1. Sealing.
  2. Open all doors, wardrobes, drawers, etc.
  3. Unmake the beds.
  4. Remove open liquids (left-over coffee, wash-water, etc.).
  5. Remove food.
  6. Remove plants and domestic animals (aquariums, and so forth).
  7. Remove undeveloped photographic plates and film.
  8. Remove dressings for wounds, medications whether open or in packages (especially charcoal).
  9. Remove gas mask filters.
  10. Prepare to inspect the result.
  11. Evacuate the occupants.
  12. Collect keys. (All entry door keys.)


  1. Gas concentration and treatment period depend on

– type of pest,

– temperature,

– degree to which the premises are filled and

– air-tightness of the building.

For indoor temperatures of above + 5° C one ordinarily uses 8 g./m3  prussic acid.

Treatment period: 16 hours, unless particular conditions, e.g. closed construction, permit a shorter period. In warm weather the time may be reduced to 6 hours. With temperatures under + 5° C it should be extended to at least 32 hours.

The aforesaid concentration and duration apply for bedbugs, lice, fleas etc., and eggs, larvae and pupae.

For ringworms, in temperatures of above 10° C, 16 g./m3 and 21 hours’ application time. Flour moths, as for bedbugs.


  1. Gassing a building:
  1. Check to make sure all persons have left the building.
  2. Unpack the Zyklon cases. For each floor, prepare the necessary quantity.
  3. Distribute the cans. One man goes into the building, receives and distributes the cans brought to him by the work team. (He has them placed beside the sheets of paper.)
  4. Dismiss the work team.
  5. Deploy the guard; the leader of the gassing team gives them his orders.
  6. Check that the sealing and evacuation are complete.
  7. Put on all gas protection gear.
  8. Open the cans and pour out the contents. Spread the contents out thinly, so that the Zyklon evaporates quickly and the required concentration of gas is reached as soon as possible. The treatment begins on the highest floor, the cellar is treated before the ground floor if the former has no exits. Rooms already treated should not be entered again, if possible. The treatment is carried out slowly and methodically. Go slowly especially on stairways. Interrupt the treatment only in case of emergency.
  9. Lock and seal the entry doors (do not forget the keyhole) and give the keys to the gassing team leader
  10. On every outer door place a notice reading as follows: “WARNING: Poison gas – danger of death – entry forbidden.” If necessary, the warning sign must be in several languages. It must in any case include at least 1 clearly visible death’s head.
  11. All gas protection gear, resuscitation equipment and residual gas detectors must be to hand. Every member of the gassing team must know where these items are.
  12. At least 1 member of the gassing team remains always near the building being gassed. The guard must be notified of his position.
  1. Aeration:

Aeration presents a great danger both for participants and non-participants. Therefore it must be carried out with particular caution and gas masks must always be worn. In principle it must be done in such a way as to be able to obtain fresh air in the shortest time and so that the gas is evacuated from a side where there is no risk to non-participants. If aeration is difficult, a man having received special training remains before the building to observe the gas’s evacuation.

  1. Make sure that no person not involved with the gassing remains in the vicinity of the building.
  2. Post the guards so as they can observe the entrances to the building without being disturbed by the evacuated gas.
  3. Put on gas masks.
  4. Enter the building. Shut the doors but do not lock them.
  5. First open the windows on the side of the building opposite the wind direction. Aerate one floor after the other. Begin with the ground floor and take a pause of at least 10 minutes after each floor.
  6. In each room of the building the hallway doors, connecting doors and windows must be opened. If any windows are difficult to open, they may be left closed until after most of the gas has been evacuated.
  7. Planking and other sealing items that cannot be put away easily may be removed after most of the gas has been evacuated.
  8. In freezing conditions or when there is risk of freezing, make sure that heating systems and water lines do not freeze.
  9. Rooms with valuable contents such as wardrobes etc. may be locked again as soon as the windows are opened.
  10. Block the doors and windows so that they do not close on their own.
  11. Seals on chimneys shall be removed after the provisional all-clear.
  12. The aeration must last at least 20 hours.
  13. The guard must remain near the building throughout the aeration.

XII. Provisional all-clear:

A gassed room can be provisionally opened to access once the paper strips used as residual gas detectors – with windows and doors open – show a blue paler than the middle of the colour scale of reference. Only tasks of aeration and arrangement may be carried out in provisionally opened rooms. In no event may anyone rest or sleep in them. The windows and doors must always be kept open.

XIII. Arrangement work after the provisional all-clear:

  1. Remove the remnants of Zyklon from the gassed rooms. In general they are to be returned to the factory along with the cans and cases. Remove the inscription “Poison” from the cases before returning them. Moist, wet or dirty remnants and damaged cans must never be returned. They can be thrown in the rubbish bin or on the cinder heap but must never be emptied into drains.
  2. Mattresses, straw sacks, cushions, upholstered furniture and similar objects must be shaken or beaten in the open for at least one hour (in rainy weather, at least two hours in the vestibule) under the supervision of the gassing team’s chief or his deputy.
  3. The stuffing of straw sacks should be replaced, when possible. The old stuffing need not be burned – it can be reused after further aeration.
  4. If chimney pots have been plugged, the plugging material must be fully removed to avoid the danger of ovens and fireplaces not having enough draft, which will cause carbon monoxide poisoning.
  5. After the final all-clear a gassing report in the prescribed form must be completed, in two copies. In particular, it must include:
  1. a) the volume of space gassed,
  2. b) the quantity of Zyklon used,
  3. c) the name of the gassing team’s chief,
  4. d) the names of the other personnel involved,
  5. e) the duration of the action,
  6. f) the date and hour of the final all-clear for the disinfested rooms.

XIV. Final all-clear:

  1. In no case earlier than 21 hours from start of aeration.
  2. Bring back into the rooms all objects removed for shaking out.
  3. Windows and doors shall be closed for one hour.
  4. Rooms with heating must have their temperature brought to at least 15° C.
  5. Detection of residual gas. The paper strips must not be of a blue more pronounced than the brightest degree of the colour scale of reference, even when placed between sheets or mattresses laid together, and in places difficult of access or difficult to aerate. If this is not the case, the aeration must be continued and residual gas detection repeated after a few hours.
  6. In buildings to be used as soon as possible for sleeping, proceed with residual gas detection in each room separately. In no case may persons spend the night in a room that has been gassed on the same day. The windows must always remain open during the first night of the room’s reuse.
  7. The gassing team’s chief or his deputy may not leave the building until the final all-clear has been given for the last room.

Published by the Health Authority of the Protectorate of Bohemia and Moravia in Prague

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