TRANSLATION OF DOC. NO. NI-9912 Office of Chief of Counsel for War
DIRECTIVES FOR THE USE OF PRUSSIC ACID (ZYKLON) FOR THE DESTRUCTION
OF VERMIN (DISINFESTATION)
I. Properties of Prussic Acid (Hydrocyanic acid)
Prussic acid is a gas which is generated by evaporation.
- Boiling Point: 25 degrees Centigrade
- Freezing Point: -15 degrees Centigrade
- Specific Gravity: 0.69
- Steam density: 0.97 (Air: 1.0)
- The liquid evaporates easily
- Liquid: Transparent, Colorless
- Smell: Peculiar, Repulsively Sweet
- Extraordinarily Great Penetrative Powers
- Prussic Acid is Soluble in Water
Danger of Explosion:
75 g. prussic acid 1 cbm air. (Normal application approx. 8-10 g. per
cbm, therefore, not explosive). Prussic acid may not be brought into contact
with an open flame, glowing wires, etc. because then it burns up slowly
and loses all its effectiveness (carbonic acid, water and nitrogen are
Toxic effects on warm-blooded animals:
Since the prussic acid has practically no indicative irritant effect
it is highly toxic and very dangerous. Prussic acid is one of the most
powerful poisons. 1 mg. per kg. of body weight is sufficient to kill a
human being. Women and children are generally more susceptible than men.
Very small amounts of prussic acid do not harm the human body, even if
breathed continuously. Birds and fishes are particularly susceptible to
Toxic effects on insects:
The effects of prussic acid on insects do not depend on the temperature
to the same extent as that of other gases, that is, it is effective in
low temperatures (even at 5 degrees Centigrade). The eggs of many insects,
particularly of bugs and lice, are more susceptible than the full-grown
Toxic effects on plants:
The degree of toxicity depends on the type of vegetation on the plants.
Plants with thick leaves are less susceptible than those with thin ones.
Mildew and dry-rot are not killed by prussic acid. Prussic acid does not
II. Method of Using Prussic Acid
ZYKLON is the absorption of a mixture of prussic acid and an irritant
by a carrier. Wood fibre discs, a reddish brown granular mass (Diagriess
- Dia gravel) or small blue cubes (Erco) are used as carriers.
Apart from serving its purpose as indicator, this irritant also has the
advantage of stimulating the respiration of insects. Prussic acid and the
irritant are generated through simple evaporation. Zyklon will keep for
3 months. Use damaged cans first. The contents of a can must all be used
up at once. Liquid prussic acid damages polish, lacquer, paint, etc. Gaseous
prussic acid is harmless. The toxicity of the prussic acid remains unchanged
by the addition of the irritant; the danger connected with it is however
Zyklon can be rendered inoffensive by combustion.
III. Possible Poisoning
1. Slight poisoning:
Dizziness, headache, vomiting, general feeling of sickness, etc. All
these symptoms pass if one immediately gets out into the fresh air. Alcohol
reduces resistance to prussic acid gassing, therefore, do not drink alcohol
Prescribe: 1 tablet Cardiazol or Veriazol in order
to prevent heart disorders, if necessary, repeat after 2-3 hours.
2. Severe poisoning:
The affected person will collapse suddenly and faint. First Aid:
fresh air, remove gas mask, loosen clothing, apply artificial respiration.
Lobelin, intermuscular 0.01 g. Do not give camphor injections.
(page 2 of original)
3. Poisoning through the skin:
Symptoms as for 1. Treat in the same way.
4. Stomach poisoning:
Treat with Lobelin, intermuscular 0.01 g., ferrous sulphate, burnt
IV. Protection Against Gas
When fumigating with Zyklon use only special filters, e.g., the filter
insert "J" (blue-brown) of the Auergesellschaft Berlin or of
the Draegerwerke, Luebeck. Should gas seep through the mask, leave the
building immediately and change filters after also checking the mask and
its fit to see whether they are tight. The filter insert is exhausted if
gas enters through the mask. If using the filter "J", first move
around in the open air for approx. 2 minutes so that a certain amount of
moisture from the breath may gather in the filter insert. Under no circumstances
should filters be changed inside gas-filled rooms.
A disinfestation squad consisting of at least 2 members is employed
for each disinfestation project. The fumigation chief is responsible for
the fumigation. His particular duties are inspection, airing, release and
safety measures. The fumigation chief is to appoint a deputy in case he
has to leave. The orders of the fumigation chief are to be followed without
Untrained personnel or persons who are trained but do not yet hold a certificate
may not be called in to work on gassing operations, nor may they be taken
into gas-filled rooms. The fumigation chief must also know where to contact
his personnel. Every person must at all times be able to prove that he
has official authorization for the use of prussic acid for extermination
Each member must at all times carry with him:
- His own gas mask.
- At least 2 special filter inserts against Zyklon prussic acid.
- The leaflet 'First Aid for Prussic Acid Poisoning.'
- Work order.
- Authorization certificate.
Each disinfestation squad must at all times carry:
- At least 3 special inserts as extra stock
- 1 gas detector
- 1 instrument for injecting Lobelin.
- Lobelin 0.01 g. ampoules.
- Cardiazol, Veriazol tablets.
- 1 lever or pickhammer for opening the cans of Zyklon.
- Warning signs as per regulation.
- Material for sealing.
- Sheets of paper to serve as pads.
All equipment is to be kept clean and in good order at all times. Damage
to equipment is to be repaired at once.
VII. Planning Fumigations
1. Can the fumigation be carried out at all?
- (a) Type of building and situation
- (b) Condition of roof
- (c) Condition of windows
- (d) Presence of heating shafts, air shafts, breaks in the walls,
2. Determine the kind of vermin to be exterminated.
3. Calculate the space (Do not rely on drawings but take measurements yourself.
Take only outside measurements, including walls).
4. Prepare personnel (Remove domestic animals, plants food and drink, undeveloped
photographic plates, and gas mask filters).
5. Find which opening will be particularly difficult to seal (Air shafts,
drains, large openings which have been boarded up, roofs).
6. Settle necessary safety measures (Guarding, work detachment for sealing).
7. Fix the date for the fumigation and the time for clearing the building.
8. If necessary, arrange safety measures for the neighborhood in good time.
9. Notify authorities.
VIII. Preparation for Fumigation
- Open all doors, closets, drawers, etc.
- Pull bedding apart.
- Remove all liquids (remains of coffee, washing water, etc.).
- Remove all food.
- Remove all plants and domestic animals (aquaria, etc.).
- Remove all undeveloped photographic plates and films.
- Remove adhesive plaster, all medical supplies, whether open or in
paper bags (particularly coal).
- Remove all gas mask filters.
- Prepare for check on results.
- Clear out personnel.
- Take over keys (every door key).
IX. The Strength of the Gas and Time Required for it to Take Effect
- the type of vermin
- the temperature
- the amount of furniture in the rooms
- the imperviousness of the building
For inside temperatures of more than 5 degrees Centigrade, it is customary
to use 8 g. prussic acid per cbm.
Time needed to take effect: 16 hours, unless there
are special circumstances such as a closed-in type of building, which requires
less time. If the weather is warm it is possible to reduce this to a minimum
of 6 hours. The period is to be extended to at least 32 hours if the temperature
is below 5 degrees Centigrade.
The strength and time as above are to be applied in the case of bugs, lice
fleas, etc., with eggs, larvae and chrysalises.
For clothes-moths: temperatures above 10 degrees Centigrade, 16 g. per
cbm and 24 hours to take effect. For flour-moths: same as for bugs.
X. Fumigation of a Building
- Check that everybody has left the building.
- Unpack the boxes of Zyklon. Make the appropriate amount ready for
- Distribute the cans. One man to go into the building and receive
the cans which have been brought up by the work detachment and to distribute
them. (Have them put next to the pads.)
- Dismiss the work detachment.
- Post the guard. Fumigation chief to instruct the guard.
- Check that sealing and cleaning have been completed.
- Put on gas masks.
- Open the cans and pour out their contents. The contents are to be
spread thinly so that the Zyklon can evaporate quickly and the necessary
density of the gas can be achieved as soon as possible. This process is
to start on the top floor but the cellar is to be dealt with before the
ground floor, should the cellar have no exit. Rooms which have been dealt
with should, as far as possible, not be re-entered. The processing is to
be done slowly and calmly. The staircase particularly should only be used
slowly. The processing may only be interrupted in an emergency.
- The exit door to be locked, sealed (do not forget the keyhole) and
its key handed over to the fumigation chief.
- On the door fix a warning sign with the legend :Danger - Poison
Gas. Danger to Life. No Admittance." This warning sign is to be in
several languages if necessary, and in any case it must be marked with
at least 1 death's head, clearly visible.
- Gas masks, apparatus for resuscitation and gas detectors are to
be kept available at all times. Every member of the fumigation squad must
know where these objects are located.
- At least 1 member of the fumigation squad must always remain near
the building which is being fumigated. The guard must be notified of his
The airing is connected with the greatest danger for those participating
and others. Therefore, it must be carried out particularly carefully and
a gas mask should always be worn. The airing should take place according
to the following principles: pure air should always be within reach in
the shortest possible time and the gas should flow out to that side where
it cannot endanger people who are not participating. Should the airing
be difficult, one trained man should remain in front of the building in
order to watch how the gas is blowing away.
- Take care to see that no strangers remain in the vicinity of the
- Post the guards in such a way that they are not annoyed by the gas
as it blows out, but can still watch the entrances to the building.
- Put on gas mask.
- Enter building. Close door, but do not lock it.
- First open the windows on that side of the building where there
is no wind. Air floor by floor. Start on the ground floor and after each
floor, take at least 10 minutes rest.
- The doors leading to the corridor, connecting doors between rooms
and windows must be opened in each room. Should there be difficulty in
opening any of the windows, they should only be opened after most of the
gas has blown away.
- Partitions and other methods used to seal the room which cannot
be replaced quickly should only be removed after most of the gas has blown
- Care should be taken to see that the heating system and water pipes
do not freeze should there be frost or danger of it.
- Rooms with valuable contents, such as clothing stores, etc. may
be locked again as soon as the windows have been opened.
- Windows and doors which have been opened should be fastened in such
a way that they cannot slam.
- Covers in chimneys may be removed after the provisional release
of the building.
- The airing should continue for at least 20 hours.
- The guard should remain near the building for the whole of this
XII. Provisional Release
A fumigated room may be released provisionally as soon as the paper
strip of the gas detector is of a lighter blue than the center color pattern,
when the doors and windows are open. Only work concerned with airing and
cleaning up may be done in the rooms which have been provisionally released.
Under no circumstances may anyone rest or sleep in these rooms. The doors
and windows must be left open all the time.
XIII. Cleaning Up After Provisional Release
- Remove remains of Zyklon from the fumigated rooms. They should generally
be sent back to the factory in the same way as cans and boxes. Before boxes
are sent back from the fumigated rooms, the inscription "Poison"
must be removed from them. Damp, wet, or soiled remains, as well as damaged
cans may not be sent back under any circumstances. They may be thrown on
a rubbish or slag heap, but may never be emptied into drains.
- Mattresses, straw palliasses, pillows, upholstered furniture and
similar items must be shaken or beaten for at least one hour in the open
air (if rainy, at least 2 hours in the hall) under the supervision of the
fumigation chief [or his assistant].
- If possible, the stuffing of straw palliasses should be changed.
The old stuffing may not however, be burnt, but may be re-used after it
has been aired for a further period.
- Should the chimneys have been covered from above, these coverings
must be removed carefully, since otherwise there is a danger that the fires
in the stoves and hearths will not have sufficient draught, which may cause
carbon monoxide poisoning.
- After the final release has been made, two copies of a fumigation
report are to be filled in, in the prescribed manner. the following points
in particular should be shown:
- (a) Volume of fumigated rooms.
- (b) Amount of Zyklon used.
- (c) Name of fumigation chief.
- (d) Names of other personnel.
- (e) Time required for gas to take effect.
- (f) Time at which disinfested rooms were released.
XIV. Final Release
- Under no circumstances less than 21 hours after airing was started.
- All items removed for beating are to be taken back into the room.
- Doors and windows to be closed for one hour.
- In rooms with heating facilities, a temperature of at least 15 degrees
Centigrade must be produced.
- Gas detecting: The paper strip may not show a darker blue than the
lightest color, even between blankets and mattresses which have been placed
on top of each other, or in rooms which are not easily accessible and which
it is difficult to air. Should this not be the case, airing must continue
and the check for gas repeated after a few hours.
- The check for gas must be made in each room of buildings which are
again to be used as sleeping accommodation as soon as possible. Under no
circumstances may anyone sleep in a room which has been fumigated in the
night following the fumigation. The windows must always remain open during
the first night that the room is used again.
- The fumigation chief or his deputy may not leave the building until
the very last room has been finally released.
(Issued by the Health Institution of the Protectorate Bohemia and Moravia
CERTIFICATE OF TRANSLATION
I, Dorothea L Galewski, ETO #34079, hereby certify that I am thoroughly
conversant with the English and German languages; and that the above is
a true and correct translation of Document No. NI-9912.
(Signed: Dorothea L Galewski / ETO 34079)
This report is taken from the Zundelsite