Somewhere between 2.6 and 3.8 million American men and women served in
Vietnam during the years 1965 through 1971, the years when chemical
herbicides were being used to denude the jungle and destroy enemy
crops. Military records do not allow a more accurate determination of
the true number who served.
Alongside the humans serving in Vietnam, there were 3895 military
working dogs, almost all of them purebred German shepherds. (Among
the 3895, there were 64 Labrador or golden retrievers used as trackers;
the other 98.3 percent were German shepherds.) These dogs served as
scouts, sentries, trackers, mine detectors, and tunnel explorers. About
91% of these dogs were "intact" (uncastrated) males.
When a military working dog dies, regardless of the circumstances of
death or the duty location, an autopsy is performed by a veterinarian,
and a standardized set of tissue specimens and organs are sent to the
Armed Forces Institute of Pathology in Washington, D.C.
During the late 1980s, researchers compared autopsy records of 1167
military working dogs with Vietnam service against autopsy records of
791 military working dogs who served in the continental U.S. and saw no
Vietnam service. In a separate study, the stateside dogs were also
compared to 437 dogs that died in Okinawa, because many dogs that
served in Vietnam were sent to Okinawa after the war.
These studies showed that dogs who served in Vietnam were about twice
as likely (1.8 times as likely) to have cancer of the testicles,
compared to military working dogs who served only in the states.
Likewise, military dogs that died in Okinawa were about twice as likely
(2.2 times as likely) to have testicular cancer as dogs who served only
in the states. A separate study was then conducted, excluding the dogs
who had testicular cancer. Among the non-cancer dogs, there was clear
evidence of significant deterioration of the testicles in those dogs
who served in Vietnam (compared to dogs who served only in the U.S.):
degeneration of the testicles, atrophy (shrinking) of the testicles,
and evidence of a below-normal ability to produce sperm.
Dogs have often served as sentinels of human disease. Back in 1938, the
well-known researcher W.C. Hueper showed that beta-naphthylamine caused
bladder cancer in dogs. In 1954, researchers showed that another
industrial chemical, 4-aminodiphenyl, produced bladder cancer in dogs.
 In 1980, a study of 8760 pet dogs showed that bladder cancer in
dogs correlated with residence in industrialized counties in the U.S.
and Canada; this same study showed that bladder cancer in men and women
was similarly correlated with residence in industrialized areas. "The
findings of this study suggest that the bladder cancer experience of
pet dogs resembles that of human beings living in the same general
locale," the study concluded.
Pet dogs are particularly relevant in such studies because 40 million
pet dogs share their owner's domestic environment yet do not indulge in
behavior that could confuse or confound the interpretation of
epidemiologic studies: dogs don't smoke, and they usually don't work.
In 1983, a study of pet dogs with the asbestos-related lung disease,
mesothelioma, showed that their disease correlated with household
members who (a) worked in an asbestos-related job, or (b) had an
asbestos-related hobby or (c) applied flea powder to their dog.
For these reasons, the finding of testicular cancer and testicular
dysfunction in dogs who served in Vietnam was an eye- opener, and it
soon led to a comparison of 271 human veterans with testicular cancer
to 259 veterans without testicular cancer, to see whether Vietnam
service was related to testicular cancer. This study revealed that,
like dogs, human veterans of Vietnam were about twice as likely (2.5
times as likely), to have testicular cancer compared to veterans who
did not serve in Vietnam.
Naturally, the question occurs, what aspects of military service in
Vietnam caused testicular cancer in men, and testicular cancer and
dysfunction in military working dogs?
An obvious suspect is Agent Orange, which was sprayed in large
quantities (11.2 million gallons, or 42.4 million liters) over 3.6
million acres (1.5 million hectares) of Vietnam. Agent Orange, named
for the orange stripe on its 55-gallon storage containers, was a 50-50
mixture of two herbicides: 2,4,5-T and 2,4-D. One of these, 2,4,5-T,
was banned in the U.S. about 1980 because evidence indicated that it
could cause birth defects in humans; the other half of Agent Orange,
2,4-D, remains in wide use throughout the U.S. where it is popular for
killing dandelions and other broad-leaf plants in lawns, and as an
agricultural weed killer.
During manufacture, the herbicide 2,4,5-T becomes contaminated with
dioxin unavoidably. According to the National Academy of Sciences, the
average dioxin contamination in Agent Orange in Vietnam was 2 parts per
million (ppm). An estimated total of 368 pounds of dioxin was sprayed
onto Vietnam's land and people during the 7-year spray program.
However, a recent study of Vietnam veterans that tried to estimate
2,4,5-T exposure and link it to testicular cancer found that only Navy
men had elevated levels of testicular cancer associated with 2,4,5-T
exposure; men in the other services showed no such effect of exposure
to 2,4,5-T. The authors of that study speculated that Navy men
might also have been exposed to fuels (oil and gasoline), which
previous studies have linked to testicular cancer.
The other half of Agent Orange, herbicide 2,4-D, is also a suspect.
Although the manufacturers of 2,4-D claimed for years that their
products were not contaminated with dioxin, this claim has now been
shown to be false, using the manufacturers' own data.
Dioxin has been shown to damage the reproductive organs and systems of
many animal species, including men and women.
A study of pet dogs in the U.S. found excess cancers (lymphomas)
associated with 2,4,-D lawn spraying. And a study of 32 farmers who
sprayed 2,4-D, compared to a control group of 25 unexposed farmers,
revealed significant effects on the exposed farmers: diminished sperm
count, increased number of sperm with poor motility (swimming ability);
increased numbers of dead sperm; and increased numbers of malformed
No federal agency keeps close track of pesticide use in the U.S.;
however U.S. Environmental Protection Agency (EPA) estimates that
farmers apply 25 to 30 million pounds (11.3 to 13.6 million kilograms)
of "active ingredient" of 2,4-D each year in the U.S. Non-agricultural
use of 2,4-D in the U.S. is estimated to total another 12 to 15 million
pounds (5.4 to 6.8 million kilograms) of "active ingredient" per year.
 The "active ingredient" of a pesticide is only 0.5% to 5% of the
total formulation so these "active ingredient" amounts must be
multiplied by anywhere from 20 to 200 to get the total 2,4-D
formulation used each year. The bulk of the formulation is secret
ingredients (called "inerts") which are, themselves, often toxic
Other chemicals suspected of causing testicular cancer and dysfunction
in dogs and humans who served in Vietnam are the antibiotic
tetracycline and the pesticide malathion. Many military dogs in Vietnam
suffered from ear infections and other diseases. Therefore, many
received one or more doses of tetracycline during their tour of duty.
Tetracycline is strongly absorbed by sperm in mammals, and is known to
cause testicular atrophy (shrinkage), and diminished sperm quality in
humans and dogs.
The other suspicious candidate is malathion. The same military unit
that sprayed Agent Orange also sprayed DDT and malathion extensively in
the vicinity of U.S. troops, to reduce the dangers of malaria carried
by mosquitoes. It has been reported that 44% of the land of southeast
Asia, mainly Vietnam, was sprayed with malathion during the war.
Furthermore, military working dogs in Vietnam were dipped in a 0.5%
solution of malathion to kill disease-carrying ticks. Malathion is
known to cause testicular atrophy and damage to the sperm-generating
cells of laboratory animals.
Malathion is widely use throughout the U.S. today for mosquito control
though not for fear of malaria. Mosquitoes are simply a nuisance. EPA
estimates that 4 to 6 million pounds (1.8 to 2.7 million kilograms) of
"active ingredient" of malathion are sprayed in the U.S. each year. The
yearly total of malathion formulation sprayed is, again, 20 to 200
times this amount.
Sperm count in men throughout the industrialized world appears to be
dropping. (See REHW #343 and #432.) Testicular cancer is the most
prevalent cancer among white males between the ages of 25 and 34 years
and the second most common in the 35-to-39 age group. The causes of
testicular cancer are thought to be environmental because the rates
vary widely from one location to another. During the last 15 years, the
rates have increased rapidly (2.3% to 3.4% per year) in many
It may take scientists many decades to tell us all we would like to
know about a complex chemical like dioxin, or malathion. However, we
already know enough to act: To guide our personal choices, and new
public policies, to minimize the danger to ourselves, our families, and
our communities, we need only to remember that chemicals not used
cannot cause harm. This we can learn from the dogs of war.
 Harold Fallon and others, VETERANS AND AGENT ORANGE: HEALTH EFFECTS
OF HERBICIDES USED IN VIETNAM (Washington, D.C.: National Academy
Press, 1993), pg. 3-1.
 Howard M. Hayes and others, "U.S. Military Working Dogs with
Vietnam Service: Definition and Characteristics of the Cohort,"
MILITARY MEDICINE Vol. 159, No. 11 (November 1994), pgs. 669-675.
 H. M. Hayes and others, "Excess of Seminomas Observed in Vietnam
Service U.S. Military Working Dogs," JOURNAL OF THE NATIONAL CANCER
INSTITUTE Vol. 82, No. 12 (June 20, 1990), pgs. 1042-1046.
 W.C. Hueper and others, "Experimental Production of Bladder Tumors
in Dogs by Administration of Beta-Naphthylamine," The JOURNAL OF
INDUSTRIAL HYGIENE AND TOXICOLOGY Vol. 20, No. 1 (January 1938), pgs.
 A.L. Walpole and others, "Tumours of the Urinary Bladder in Dogs
After Ingestion of 4-aminodiphenyl," BRITISH JOURNAL OF INDUSTRIAL
MEDICINE Vol. 11 (1954), pgs. 105-109.
 Howard M. Hayes and others, "Bladder Cancer in Pet Dogs: A Sentinel
for Environmental Cancer?" AMERICAN JOURNAL OF EPIDEMIOLOGY Vol. 114,
No. 2 (1981), pgs. 229-233.
 Lawrence T. Glickman and others, "Mesothelioma in Pet Dogs
Associated with Exposure of Their Owners to Asbestos," ENVIRONMENTAL
RESEARCH Vol. 32, No. 2 (December 1983), pgs. 305-313.
 Robert E. Tarone, and others, "Service in Vietnam and Risk of
Testicular Cancer," JOURNAL OF THE NATIONAL CANCER INSTITUTE Vol. 83,
No. 20 (October 16, 1991), pgs. 1497-1499.
 Fallon, cited above, pg. 2-4.
 Tim A. Bullman and others, "Risk of Testicular Cancer Associated
with Surrogate Measures of Agent Orange Exposure among Vietnam Veterans
on the Agency Orange Registry," ANNALS OF EPIDEMIOLOGY Vol. 4, No. 1
(January 1994), pgs. 11-16.
 U.S. Environmental Protection Agency, ESTIMATING EXPOSURE TO
DIOXIN-LIKE COMPOUNDS VOL. II PROPERTIES, SOURCES, OCCURRENCE AND
BACKGROUND EXPOSURES [EPA/600/6-88/005Cb June 1994 External Review
Draft] (Washington, D.C.: U.S. Environmental Protection Agency, 1994),
Table 3-18 on pg. 3-58.
 Arnold Schecter, editor. DIOXINS AND HEALTH (New York: Plenum
Press, 1994); see, for example, pgs. 26, 145, 318, and 332, among
 Howard M. Hayes and others, "Case-Control Study of Canine
Malignant Lymphoma: Positive Association With Dog Owner's Use of 2,4-
Dichlorophenoxyacetic Acid Herbicides," JOURNAL OF THE NATIONAL CANCER
INSTITUTE Vol. 83, No. 17 (September 4, 1991), pgs. 1226-1231.
 D. Lerda and R. Rizzi, "Study of reproductive function in persons
occupationally exposed to 2,4-dichlorophenoxyacetic acid (2,4-D)"
MUTATION RESEARCH Vol. 262 (1991), pgs. 47-50.
 Arnold L. Aspelin, PESTICIDES INDUSTRY SALES AND USAGE; 1992 AND
1993 MARKET ESTIMATES [733-K-94-001] (Washington, D.C.: U.S.
Environmental Protection Agency, June 1994), pg. 19.
 John H. Bukowski and Leroy W. Meyer, "Simulated Air Levels of
Volatile Organic Compounds Following Different Methods of Indoor
Insecticide Application," ENVIRONMENTAL SCIENCE & TECHNOLOGY Vol. 29,
No. 3 (1995), pgs. 673-676.
 Paul B. Jennings and others, "A Survey of Diseases of Military
Dogs in the Republic of Vietnam," JOURNAL OF THE AMERICAN VETERINARY
MEDICAL ASSOCIATION Vol. 159, No. 4 (August 15, 1971), pgs. 434-440.
 Fallon, cited above, pg. 3-14.
 K. Balasubramanian and others, "Effect of malathion on the testis
of male albino rats," MEDICAL SCIENCE RESEARCH Vol.15 (1987), pgs. 229-
 Hans-Olav Adami and others, "Testicular Cancer in Nine Northern
European Countries," INTERNATIONAL JOURNAL OF CANCER Vol. 59 (1994),
Descriptor terms: vietnam war; military; army; navy; marines; air
force; herbicides; veterans; dogs; german shepherds; labrador
retrievers; golden retrievers; okinawa; testicular cancer; sperm count;
testicular atrophy; 4-aminodiphenyl; beta-naphthylamine; bladder
cancer; asbestos; mesothelioma; flea powder; agent orange; 2,4,5-t;
2,4-d; birth defects; agriculture; farming; dioxin; fuel; oil;
gasoline; lymphoma; pesticide use data; inert ingredients; antibiotics;
tetracycline; malathion; mosquito control;