Chemical and biological warfare had been practiced long before the 20th century, albeit in primitive forms. Poisoning wells with carcasses and using smoke to drive opponents out of cover were not new concepts. However, chemical warfare took a deadly modern turn during the First World War, when the chemical industries of the belligerent powers produced increasingly deadly poison gases for use on the battlefield.
Chemical Warfare.
In 1899, the Hague Declaration Concerning Asphyxiating Gases banned
"the use of projectiles, the sole object of which is the diffusion of
asphyxiating or deleterious gases." However, during the First World
War, the Germans took the position
that shells that contained both high explosive and poison gas were not
banned, since the gas delivery was not their "sole" object. The Germans
also decided that delivering gas from storage cylinders was legal,
since these were not projectiles. The Allies responded in kind.
The first poison gases were choking gases like
chlorine or
chlorine-derived phosgene that destroy the lining of the throat and
lungs. These are toxic, but were only moderately effective as weapons,
because they cause damage only when inhaled, dissipate quickly, are
easily detected, and can
be protected against with relatively simple masks. The same was
largely true of the so-called blood gases, which included hydrogen
cyanide and its derivatives. Cyanide is very toxic when inhaled but
dissipates very quickly.
The next generation of chemical weapons, which came into battlefield use as the war was winding down, were vesicants or blistering agents, such as mustard and Lewisite. These were much more suitable as weapons. They are oily liquids, which take some time to dissipate (days in the case of mustard); they can blister unprotected skin, so a gas mask is not sufficient protection; and they tend to disable rather than kill -- which, paradoxically enough, is often advantageous in warfare.
The Versailles Treaty absolutely prohibited any
production or stockpiling of chemical agents by Germany. During the
1920s, chemical agents came to be viewed as uniquely
horrible weapons, and the 1925 Protocol on the Prohibition of the Use
in War of Asphyxiating, Poisonous or Other Gases, and of
Bacteriological Methods of Warfare (known as the Geneva Protocol)
was ratified by many nations. Curiously, the United States did not ratify
this protocol until the 1970s, although they largely respected its
prohibitions. The Geneva Protocol banned the use of chemical and
biological weapons in warfare, but not their production and
stockpiling. Most industrially advanced nations maintained stockpiles
as a
deterrent against use of these weapons by other powers.
In November 1936, German insecticide researchers
at I.G. Farbin synthesized an organophosphate compound that proved to
be highly toxic to both insects and mammals. This compound, Tabun, was
much too dangerous for use as an insecticide, but the German armed
forces quickly recognized its potential as a chemical warfare agent.
Tabun was the first of a third generation of chemical
weapons, nerve agents, which act by destroying the body's ability to
turn off nerve
impulses. Nerve agents are extraordinarily toxic and tend to kill
rather than disable. Like mustard, they are oily liquids that take some
time to dissipate, and they can penetrate unprotected skin. However,
Tabun is unstable and has a distinctive odor. In late 1938 the German
researchers discovered Sarin, which is considerably more toxic than
Tabun, more stable, and has almost no odor when purified. By spring of
1942 the Germans had put Tabun into mass production and were working on
production facilities for Sarin. Production was limited by supplies of
raw materials, such as phosphorus, which the Germans obtained from phosphate deposits in North Africa.
These sources became unavailable to the Germans as the result of
Operation TORCH, and production fell far short of goals. The Germans
also discovered Soman in the spring of 1944. Soman is twice as toxic as
Sarin and acts very quickly, so that antidotes such as atropine are
difficult to administer in time to save the victim. Neither Sarin nor
Soman were stockpiled in significant quantities.
British
researchers at the University of Cambridge apparently discovered
nerve agents in 1941, but the British discovery, DFP, was not much more
toxic than mustard and so was not stockpiled. However, In one of the
most fortunate intelligence
failures of the
war, the Germans underestimated their own lead in nerve agents and
never used chemical weapons during the Second World War, fearing a
devastating retaliatory response. For example, Hitler ordered a nerve
gas attack on the Russians, to take
place on 20 April 1943, that was subsequently called off. Hitler also
called for the use of chemical agents in the V-2 ballistic missile, but
the limited warhead capacity of the V-2 meant that not enough agent
would survive the fiery impact of the missile to do more damage than a
conventional explosive warhead would inflict.
Japan built
up
extensive stockpiles of mustard and other first- and second-generation
chemical agents, and is alleged to have made use of them against the Chinese, who had no means of
retaliation. The precise extent and effectiveness of Japanese chemical
attacks remains controversial. One source (Japan Times) claims that 2000
attacks took place, killing 10,000 persons. Drea (2009) claims that
poison gas ("special smoke") was used during the Hankow campaign of August 1938.
The Americans were privy to British research on nerve agents, but none of the roughly two hundred organophosphates screened by American chemists were significantly more toxic than DFP, which the Americans called PF-3. A pilot plant was built to produce PF-3, but only 535 pounds were produced and PF-3 never went into the stockpile. Instead, American chemists focused on insecticides like DDT that could be used to control malaria-transmitting mosquitoes, and the American chemical weapons stockpile was based largely on mustard.
Another class of chemical agents are the tear
gases. Compounds such as bromoacetone were discovered before the First
World War and saw some use as chemical agents during that conflict.
Tear gases irritate the eyes and upper respiratory tract, but do
lasting harm only under unusual conditions. Because of their
nonlethality, they are useful for riot control, and their use in
warfare was not explicitly banned until 1997.
With one exception, there is no evidence that any of the Allies used chemical or biological agents, either in Europe or the Pacific. However, during the 1943 Italian campaign, the Americans feared that Germany might be on the brink of using chemical agents in Italy, based on prisoner of war interrogations and intelligence passed on by the Italians. On the night of 2 December 1943, a German air raid on the Italian port of Brisi sank several ships, including an American ship loaded with mustard shells that were being deployed for possible retaliatory use. The raid was highly destructive and it was difficult to determine how many of the casualties were from mustard released into the harbor, but mustard casualties likely numbered in the hundreds.
The exception was the use of tear gas during the
mopping up of Iwo Jima in May
1945. The Americans had considered using mustard gas during the battle,
but eventually decided against it, a decision Nimitz later expressed
regret over. However, Hastings (2007) claims that the Americans
unsuccessfully tried using tear gas to drive survivors of the battle
out of the extensive underground fortifications
on the island. When this failed, the survivors were burned out using a
mixture of salt water, gasoline, and oil.
Towards the end of the war, the U.S. Strategic
Bombing Survey recommended to the Joint Target Group that a new
herbicidal chemical, TN8, be used against the Japanese rice crop. This recommendation was
rejected with the terse observation that "indigenous food supplies may
be very important to the commander charged with the occupation." TN8
would not have been ready before 1946 in any case.
Biological Warfare.
Biological warfare is viewed with even more repugnance than chemical
warfare, in part because of the possibility that the use of biological
weapons could lead to a pandemic. Biological
weapons did not see use in the First World War, but they
were investigated by several of the major powers during the Second
World War. To be effective in warfare, a biological agent must be
virulent, but
not so virulent that it easily spreads to friendly troops. Furthermore,
there must be a way to deliver the agent and the agent must
be resistant to countermeasures.
One of the biological agents
investigated by several nations during the Pacific War was anthrax,
which is contracted when the spores are inhaled and carried to the
lymph nodes of the chest, where they begin to proliferate. Anthrax is
an almost ideal biological warfare agent. Inhalation anthrax is almost
100% fatal and
can be contracted from minute traces of the properly
aerosolized agent,
but it does not easily spread from person to person, so there is no
danger of a pandemic. Once symptoms are noticed -- up to several weeks
after the exposure -- the victim is usually beyond aid. However, the
disease can be successfully treated with antibiotics if detected early.
Like anthrax, plague has a high lethality, but the normal form of
the disease (bubonic plague) is transmitted via infected fleas, which
the Japanese found difficult to accomplish artificially. However,
in rare cases, plague mutates into the pneumonic form (thought to be
the cause of the Black Death of the 14th century) which is easily
spread from person to person. In this form, there is real danger
of a pandemic. Like anthrax, plague can be controlled with antibiotics.
Cholera is transmitted through contaminated water. The cholera
bacteria multiply in the intestines, where they produces a toxin that
causes severe and often fatal diarrhea. The difficulty with cholera as
a biological warfare agent is in getting the bacteria into the enemy's
water supply in sufficient concentrations to cause the disease.
Ordinary
public health measures are highly effective in controlling cholera (the
disease having played a prominent role in the historical development of
public health science) but these were lacking in China, where the
Japanese are thought to have experimented with the use of this agent.
The Japanese conducted extensive experiments in biological warfare in Manchuria under the auspices of Unit 731. Plague, cholera, and anthrax were all investigated, and it is though that the Japanese attempted to trigger a plague epidemic in China using a "flea bomb" to transmit the agent. It is unclear whether the campaign had any effect: Plague is endemic to China and cases reported at the time may have had nothing to do with the "flea bombs."
Goldstein and Dillon give a translation of the diary of Rear
Admiral Nakahara Giichi, who held a high staff position in the Navy
Ministry at the time of Pearl
Harbor. The diary entry for 9 October 1941 mentions a meeting of
bureau chiefs in which one of the topics is "Manchuria -- Microbe
fighting." It seems likely that a better translation would be "germ
warfare" and that the senior officers of the Japanese
Navy were aware of the Army's experiments in Manchuria, though there is
nothing
to indicate how detailed the Navy's information was.
Germany, Britain and the United States are all known to have engaged
in biological warfare research, probably with an eye to deterring use
of biological agents by their enemies. British research on anthrax
resulted in the contamination of the small island of Gruinard in
Scotland, which remains quarantined today. However, the only instance
of biological warfare in Europe was the deliberate flooding of marshes
behind the Anzio beachhead in Italy by the Germans to encourage
proliferation of malaria-bearing
mosquitoes. There was no known use of
biological agents by the Allies in either the Pacific or Europe.
References
The Japan Times Online, 2005-8-11 (accessed 2008-6-19)
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