Vietnam War Legacy: Birth Defects and Illness

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Vietnam War Legacy: Birth Defects and Illness

by  Scott Thacher

‘Science for the People’ Vol. 12, No. 5, September/October 1990, p. 29 – 32

Scott Thacher is a member of Science for the People Boston Disarmament/ Energy Group. He is a biochemist doing research related to toxicology.

A herbicide, Agent Orange, was spread over almost one tenth of the area of South Vietnam by the American military during the peak of the Vietnam War to defoliate forests and destroy cropland. Today, exposure to Agent Orange threatens not only the health of American and Vietnamese veterans, but it is possibly the cause of birth defects in their children. Much less is known about the long-term effects of the spraying on the ecology of South Vietnam and its people. 

According to the Veteran’s Administration, the effects of Agent Orange have been greatly exaggerated. They have grudgingly begun to investigate its effect on veterans. By March 1980, two vets had received compensation for exposure, in each case because a prior skin condition had been aggravated. Two years ago, when the effects of Agent Orange exposure were beginning to receive widespread publicity, 450 veterans had submitted claims. The number will surely continue to grow. In response to these claims of exposure, the VA promises no action, only medical examinations. The Government Accounting Office and veterans groups are not convinced that even these small efforts are being carried out properly by the VA.1) Is the VA trying to cover up the long-lasting effects of chemical warfare?

What is Agent Orange and What Are Its Health Effects? 

The active components of Agent Orange are a pair of similar chemicals, 2,4,5-T and 2,4-D. During the chemical synthesis of 2,4,5-T, and to a lesser extent of 2,4-D, a contaminant is formed called dioxin. There are many varieties of dioxin which are related in their chemical structure. The form of dioxin in 2,4,5-Tis the most toxic one known; it is called 2,3,7 ,8-tetrachlorodibenzodioxin (TCDD). It is one of the most toxic chemicals ever synthesized. Material sprayed in Vietnam had anywhere from 1 to 25 parts per million TCDD. Agent Orange now used in this country as a defoliant contains 25 parts per billion or less.2

Vietnam vets, and workers who were exposed to Agent Orange during its production since the 1930’s, have most commonly suffered from chloracne. This ailment is similar to acne but more persistent and intense. Blackheads appear initially on the face, and later on the back, shoulders and groin. If chloracne is severe enough, there will be disfigurement. Tests on rabbit ears, in the 1950’s, showed that TCDD in Agent Orange caused chloracne. Some other chlorine-containing compounds can also cause chloracne. 

Chloracne and other symptoms of dioxin poisoning do not always appear immediately and may not be seen until days or even years later. They can appear and disappear over time. This may explain why veterans have not recognized symptoms of Agent Orange exposure until recent years. Weakness, radical mood changes, numbness, tingling in the extremities and liver dysfunction are some of the reported ills. Any of these can be extremely aggravating and even debilitating. Despite the fact that dioxin’s effect had been known for the workplace, Agent Orange was described as “relatively nontoxic to man or animals” in U.S. Army manuals. The manuals did suggest the use of protective clothing during its use, but protection against breathing Agent Orange mist was not required.3

American soldiers were exposed to Agent Orange during routine preparations for spraying missions but exposure at other times may have been more serious. One vet reported that he and many others developed fevers and severe blackheads soon after an incident in 1969 near an ammunition depot near DaNang where Agent Orange was stored. The men were sent to rescue some nearby children after explosions at the depot released clouds of material, including the Agent Orange. When the soldiers complained of sickness following the explosion the military doctors told them it was combat fatigue or some kind of jungle sickness.4

Little is known about how dioxin poisons. One measure of its extraordinary if almost mysterious effects is that a guinea pig can die within days or weeks of exposure to a dose of dioxin one-billionth of its body weight. Toxicity varies greatly among animal species: dogs are 1,000 times less sensitive than guinea pigs, for example. Some animals die with severe liver damage, while others exhibit little damage to their livers upon death. Dioxin has also been shown to cause cancer in mice. 

One important case of widespread dioxin poisoning of animals was the outbreak of so-called “chick edema disease” in Georgia during 1957. The chickens were fed fat obtained as a by-product from the leather-tanning industry. During the tanning process, chlorophenols are heated and produce dioxin. This contaminant is picked up in the fat that is extracted from the hides.5

Dioxin persists in the environment, and possibly in the human body. It cannot be easily flushed out of the soil or the body because it is insoluble in water. It is very difficult to remove. In a few cases, workers, upon returning to clean up industrial plants years after major dioxin accidents, received serious exposure to residues of the chemical. One chemical plant was cast in concrete and dumped into the sea because of this problem.6

No information is available on the residues remaining all over South Vietnam. Fish caught during the war were reported to contain one part per billion of dioxin by weight.7 Since some cropland was sprayed, in addition to enormous areas of forest, the inhabitants of Vietnam may be continuing to ingest the poison. Many experimental studies show that dioxin concentrates in the food chain. The half-time for dioxin persistence in the soil has been estimated to be from three months to a year, and apparently it is decomposed by sunlight. No studies have been done to show if this has led to the disappearance of dioxin from Vietnam.

Since humans and animals do not break down dioxin, it may become stored in their bodies for years. A fifth of the workers exposed during an industrial accident involving dioxin had skin problems thirteen years later. American veterans are now complaining of problems from exposures they experienced a decade ago. The spraying was most intense during the years from 1967 to 1969, and was officially cancelled in December, 1970. 

Medical researchers have not been able to develop sensitive methods to measure the presence of dioxin in human body fat. If they could, it would help greatly in understanding the relation of dioxin poisoning to some of its unusual symptoms. Veterans groups are undertaking extensive surveys to obtain a clearer understanding of symptoms which may be related to Agent Orange exposure (see box). The National Institute of Occupational Safety and Health is maintaining a registry of those who worked in industries where Agent Orange and similar compounds were manufactured. 

Dioxin — A Cause of Birth Defects? 

The effects of Agent Orange linger on, painfully. Evidence from both American and Vietnamese veterans suggests that an increased number of birth defects among their children has occurred. A recent study by Dr. Ton That Tung, a Vietnamese surgeon, contrasted Vietnamese veterans who had fought in the South, where Agent Orange was used most heavily, with those who remained at home or fought in the North. He found that the veterans who had fought in the South were more likely to have children with birth defects than the other two groups of men. He writes that his results “suggest damage to the first generation through the father.” His studies were conducted initially by interviews with parents of all children with birth defects born from 1975 to 1978 in Yen Bai, a city of 10,000. Seven hundred soldiers had returned there from the South after the war and married women from the North. Half (15/30) of the children with birth defects in the city belonged to these veterans. Six were anencephalic — lacking in development of their brain. The malformation quickly results in death. The condition usually occurs in one out of every thousand babies born to other parents in the survey of Yen Bai. The study concluded that overall, abnormal births were about 4% (averaged from a number of cities) for fathers returned from the South or about twice as high as expected from a normal population. Dr. Tung interviewed a small number of soldiers who did not go South. They had fewer abnormal births than expected. Dr. Tung did not report whether the fathers of children with birth defects showed symptoms of dioxin poisoning.8

Dioxin has long been suspected of causing birth defects in women exposed to it during pregnancy. In animal experiments, dioxin was shown to be one of the most potent teratogens (agents causing birth defects) ever analyzed. It is by far more potent than thalidomide. When female mice were given a concentration of dioxin, one to ten parts per billion of their body weight, their litters had birth defects while they exhibited few if any symptoms of toxicity.9

Spraying of herbicides was halted in Vietnam partly because of a study by the American Association for the Advancement of Science. It correlated a two-fold increase in stillbirths in a Saigon hospital with the onset of spraying. They also found an increase in two birth abnormalities, cleft palate and spina bifida. 10 Recently, doctors at the Gynecological Hospital in Ho Chi Minh City (Saigon) contend their own statistics show an unusually large number of miscarriages and stillbirths, as well as anencephalia, because of the spraying during the war. 11

Spraying of 2,4,5-T in the U.S. was restricted to areas far away from human populations in March, 1979 because of an increase in the number of miscarriages in areas of Oregon which appeared to correlate with spraying. 

Dr. Tung, who visited the U.S. in May, 1979, says that he decided to undertake his studies because many American veterans suspect that Agent Orange was responsible for abnormalities in their children. VA medical records of approximately 120 U.S. Vietnam veterans, who claimed to have been exposed, were examined by the General Accounting Office. These records showed that 13% had reported birth defects in their children.12 Dr. Gilbert Bogen, formerly a doctor at the VA, said he independently interviewed 78 Vietnam veterans who said they were exposed to Agent Orange, one fifth of them had children with birth defects.13 In comparison, two percent of newborns in the U.S. have birth defects. These surveys could have been biased because they were not controlled. More studies need to be conducted, and soon.

A recent study by the National Toxicological Program (NTP) showed that male mice receiving dioxin or Agent Orange do not have an increase in defective offspring when mated weeks after exposure.14 This study received widespread publicity, but it may be only slightly relevant to humans. The widely varying effects of dioxin exposure on different animal species was not emphasized. The study is hardly definitive because other animal studies have shown that dioxin can cause chromosomal changes.15

The “Toxic Cocktail” 

American veterans were exposed to many other chemicals including various insecticides and an antimalarial drug now thought to be toxic. Some scientists have suggested that this “toxic cocktail” will make it impossible to evaluate the effect of dioxin alone. A synergy between the toxic effects of many compounds may be responsible for the veterans’ symptoms, but dioxin stands out as the most toxic and long-lasting one. The Defense Department suggests that the inhabitants of Seveso, Italy, where a cloud of dioxin was emitted from a chemical plant in 1976 (see SftP Nov./Dec. 1977), could be studied to understand the problems of dioxin exposure.16 This may or may not be helpful for the veterans whose exposures were more sustained and possibly more severe. 

The military is interested in downplaying the effects of Agent Orange. A scientific panel appointed by the government recently recommended that the overall war experience be considered a cause of maladies among the vets, including, presumably, symptoms of Agent Orange exposure.17 These suggestions do not take into account how limited the efforts have been to understand and describe, much less explain, the continuing sickness of veterans which resembles dioxin poisoning. The Federal government may be hesitant because of the lawsuits brought by veterans against them and the chemical manufacturers of Agent Orange. 

New Threats of Chemical Warfare 

The legacy of the veterans is a reminder of the horrors of the chemical warfare used by American forces — as if the death and destruction in Vietnam is not enough.18

 The spraying of herbicides violated the spirit of treaties outlawing chemical warfare. Technological blindness and cynicism promoted a method of war which was not only destructive, but accomplished little militarily. There is proposed legislation in the U.S. Congress to build a new variety of nerve gas projectile, the so-called binary shell. This is a mindless response to the highly exaggerated reports of Russian stockpiling of chemical weapons. If we forget the destruction of past wars and allow our government to ignore their serious after effects, the current efforts to prepare for just another “cold war” will go forward unquestioned.

>> Back to Vol. 12, No. 5 <<


  1. “Health Effects of Exposure to Herbicide Orange in South Vietnam Should be Resolved,” Report of the General Accounting Office, April 6, 1979.
  2. “Some Fumigants, the Herbicides 2,4-D and 2,4,5-T, Chlorinated Dibenzodioxins and Miscellaneous Industrial Chemicals,” International Agency for Research on Cancer (IARC), Monographs on Carcinogenic Risk, Vol. 15, August, 1977.
  3. “U.S. Ground Troops in South Vietnam Were in Areas Sprayed with Herbicide Orange,” Report of the General Accounting Office, November 16, 1979.
  4. “8 Who Lived With Agent Orange,” Boston Globe, January 21, 1980.
  5. Kimbrough, Renate, “The Toxicity of Polychlorinated Polycyclic Compounds and Related Chemicals,” Critical Reviews in Toxicology, Vol. 2, No.4, pp. 445-498, 1974.
  6. Hay, Alistair, “Toxic Cloud Over Seveso,” Nature, Vol. 262, pp. 636-638, 1976.
  7. International Agency for Research on Cancer, Monograph on Carcinogenic Risk, Vol. 15, 1977.
  8. Weisburd, Abe and Deborah Weisburd, Description of Dr. Tung’s Study, Liberation News Service, July 11, 1980. A preliminary copy of the study is available from the Agent Orange Veterans Advisory Committee, 944 Market St. Suite 500, San Francisco, CA. 94102.
  9. IARC, Monograph on Carcinogenic Risk, Vol. 15, 1977.
  10. Ibid.
  11. Weisburd, Abe and Deborah Weisburd, Liberation News Service, July 11, 1980.
  12. Report of the General Accounting Office, April 6, 1979.
  13. “Symptoms in Vietnam Veterans Exposed to Agent Orange,” Journal of the American Medical Association, Nov. 30, 1979.
  14. “Agent Orange Test Results,” Boston Globe, August 2, 1980.
  15. IARC, Monograph on Carcinogenic Risk, Vol. 15, 1977.
  16. Report of the General Accounting Office, April 6, 1979.
  17. Boston Globe, April 2, 1980.
  18. Lewallen, John, Ecology of Devastation: Indochina, Penguin Books, 1971: and Nielands, J.B., et. al., Harvests of Death, Chemical Warfare in Vietnam and Cambodia, The Free Press, 1972.