The following article is a reprint of "Chemical Warfare Intelligence Bulletin 3" emanating
from the office of the Chief of Chemical Warfare. It comprises an
excellent summary of information on developments in incendiary munitions, and
as such would be of interest to readers of Tactical and Technical Trends.
* * *
The past year has seen changes in design, construction, and tactical use
of incendiaries on the part of all warring nations. Each of the Axis nations has
developed new types of aerial bombs and incendiary munitions, with Germany
taking the lead. This bulletin provides information on these changes, with a
chart which gives a late compilation of all known types of enemy incendiary bombs.
The outstanding incendiary developed by the Germans during the past 12 months
has been a combination of an antipersonnel and incendiary bomb. Using
the 1-kilogram (2.2 lbs.) incendiary as a base, they removed the explosive
charge from the tail and added a steel extension to the nose, containing a much
more powerful charge (at first thought to be TNT but later believed to be a
picric acid derivative) and fuze. This change was due to the British having
perfected a plan for, combatting the regular oil, thermite, or magnesium incendiaries
and to the civilian personnel having become thoroughly trained in defense measures.
The effect is essentially as follows: If fire wardens attempted to put out
the fire as in the case of ordinary incendiary bombs, the explosive nose -- times
with a fuze to go off in from 1 to 5 or more minutes -- would catch them
unawares. In some cases the bomb might break in half and the two portions could
roll in different directions; thus, while fighting the incendiary section in one
location, the fire warden would be endangered by the explosive portion, possibly
lying unnoticed in a dark corner. With a lethal velocity 50 feet from the point of
explosion, this new-type bomb has meant a delay of 5 to 7 minutes in effective
Another type recently developed contained a canister of small incendiary
units scattered by a large high-explosive charge. As the bomb bursts, it throws
out about 60 metal containers with a thermite-type filling, and 6 pre-ignited
firepots of the magnesium electron type. Immediately thereafter the TNT
detonates. The weight of this incendiary bomb (110 lbs.) insures penetration, and
the explosive charge (16 pounds of TNT) produces a definite demolition
effect, wrecking partitions, doors, ceilings, flooring, etc.
A 50-kilogram (110-pound) bomb, with a filling containing 10 percent
rubber and 4 percent phosphorus in an oil gel base, has been used with questionable
success as an incendiary agent, phosphorus burns occasionally being inflicted on
personnel. Some pieces of gel remain exposed to the air a considerable time
without catching fire, while others start smoking and ignite after only a few minutes.
[Initial information on the 3 incendiaries above appeared
in Tactical and Technical Trends No. 6, p. 21.]
While to date not actively engaged in any large-scale utilizations of
incendiary bombs, the Italians have produced a 1-kilogram type similar to the
German, and in addition have developed two new ones. One of these, a 43-pound
type, may be mistaken for the Italian 50-kilogram torpedo-type bomb; the other,
a 62-kilogram bomb, carries a filling of 54 pounds of thermite.
The chart shows graphically several types of Japanese incendiary bombs
which depend mainly on thermite, phosphorus, and oil. This may indicate a
magnesium shortage. They have experimented also with the use of parachute-borne
incendiaries, with action delayed in some cases up to 6 hours. One type
used in the Philippines was made of a pasteboard composition. Stains and odors
found near points of explosion indicated that they contained picric or sulphuric
acid. However, the incendiary effect was limited.
[See Tactical and Technical Trends No. 12, p. 17 for information on
incendiaries dropped on Rangoon by the Japanese.]
Two incendiaries were dropped by an unidentified plane on Mt. Emily, near
Brookings, Oregon, in September 1942. Parts and fragments of one were
recovered. The fuze had Japanese characters stamped on it; apparently the bomb
was 125 to 150 pounds, with a nose of metal twice as thick as the body; it was
evidently not a production job, but an adaptation from a mortar
shell. Some 35 or 40 triangularly shaped pellets with a round hole in the center of each
were recovered. They appeared to be of a hard rubber composition impregnated with
particles of magnesium; it is also possible that a thermite mixture was in the
bomb. (Note: In some cases this filling is believed to contain additional chemicals
and organic materials, which may appear in later type bombs.)
See chart, next page, for other German, Italian, and Japanese incendiary bombs.
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d. Other Incendiary Munitions
Under this heading is grouped information regarding frangible grenades ("Molotov
Cocktails"), antitank grenades, and similar weapons.
The German "T B" hand-thrown prussic acid grenade is a glass cylinder
approximately 4 inches in diameter, packed in sawdust in a cardboard
container, and the container packed in sawdust again inside a metal
The Japanese have a similar type, filled with prussic acid, several cases
of these grenades having been washed up on the beach in the beginning of the
Malayan campaign. As HCN may inflame, it must be considered as an
incendiary as well as a toxic agent.
From Russia have come unconfirmed reports of the use by the Germans
of incendiaries (frangible grenades dropped from planes?) to set fire
to the high grasses of the steppes.
An Italian incendiary grenade, devised for close defensive work against
tanks and armored vehicles, consists of a quart of gasoline in a glass
bottle fitted with a metal cap. An igniter fuze, match, and wooden
handles are attached to the side of the bottle. For distances of 65 feet
or more, a safety device is utilized which operates after a long trajectory.
The Japanese developed a grenade in the form of a liquid-filled beer
bottle stamped "B Kirin Brewery Co. LTD." The fluid is essentially coal
tar. This bottle is equipped with fuze, safety lid, and safety pin.
The German Schwere Wurfgerät 40, mounted on an armored half-track
vehicle for field use, is a weapon for firing both high explosive and incendiary
ammunition. The latter is reported to be as follows: weight of projectile,
174 pounds; filling, 11 gallons of oil; markings, green and yellow band. The
projectile is reported to be a rocket type, fired electrically, with a
range of over 2,000 yards.
[See Tactical and Technical Trends No. 8, p. 28
and No. 12, p. 12 for
additional information on this weapon.]
Samples of incendiary disks, used by the Germans to fire crops, woods,
fields, etc, have been examined. They appear to be made of sponge
rubber -- colored bright yellow -- and catch fire spontaneously, forming
a black oily substance. Roughly oval in shape, 3/8-inch thick (the
largest being 9 by 16 inches and the smallest 4 by 3 inches), they
are harmless when wet, and may be moved in this condition to a safe
place where they can dry and burn themselves out.
(4) Tracer Bullets
A 13-mm (0.514-inch) incendiary tracer bullet used by the Italians is
similar in appearance to their 13-mm explosive bullet, except that the
body is colored blue instead of red.