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Case Number: 34

Case Mnemonic: VIETNAM

Case Name: Vietnam and Herbicides

Case Author: Hang Pham, Summer 1997




1. Abstract

The Vietnam war was a period of environmental destruction of Vietnam's countryside due to the extensive use of herbicides and defoliants. During the war, American strategists defended chemical defoliants by arguing that US casualties could be reduced by stripping away enemy cover. However, the effects proved more harmful to both sides. Toxic chemicals in the defoliants has had adverse effects on the ecosystem,Vietnamese population as well as US servicemen. Many years following the war the side effects of herbicides are still evident in the environment and population. 

2. Description

Most of the Vietnam's landscape is characterized by lush forests and fields similar to the mangrove forest pictured here. In the early days of the Vietnam conflict, the French recognized that the thick jungle vegetation lent favor to enemy forces who would frequently ambush military envoys. A large amount of roadside vegetation would be cleared by hand, however, the labor intensity of doing so proved inefficient. When the Americans arrived, they implemented chemical herbicides as method of clearing vegetation.

Defoliants are not creations of recent history. Developed by E.J. Kraus, chairman of the University of Chicago's botany department, the main ingredients of the chemicals used in "Agent Orange" were discovered. By infusing hormones into plants, he discovered that plant growth could be regulated and by creating sudden growth spurts in plants, they also could be destroyed. Stable hormones, regulated by the plant's natural processes, is a key component of plant health. But the introduction of specific chemicals could spur abnormal growth and in most cases plant deterioration was visible in 48 hours.

Kraus applied 2,4- dichlorophenoxyacetic acid (2,4-D) on his experimental vegetation and the results were clear. Exposed vegetation would show considerable leaf-drop followed by significant deterioration. Thinking his discovery could contribute to the war effort, Kraus brought his findings to Army scientists where they tested the chemical but did not apply them in W.W.II. Kraus's findings however, were widely embraced by civilian scientists who recognized that the 2,4-D could be used for domestic weeding purposes (Ibid). Many farmers in the American agricultural industry began using 2,4- D on cotton and soybean fields to de-leaf plants in preparation for mechanized harvesting.

The Army continued experiments with 2,4-D and discovered that specific combinations with other chemicals made 2,4-D more potent and effective. By mixing 2,4-D with 2,4,5-trichlorophenoxy-acetic acid (2,4,5-T), the compound proved to be disastrous for foliage ( When applied, there were almost immediate negative affects on plant foliage.

The apparent problem with the mixture of the two chemicals is a useless, but toxic byproduct called dioxin. The chlorinated dioxin 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) is produced in the mixture of 2,4-D and 2,4,5-T and in other combustion processes (Tschirley, 1986). Dioxins originate from different sources including toxic waste incineration, paper/pulp bleaching utilizing chlorine bleach, herbicides and pesticides. Dioxins are highly toxic and environmentally persistent compounds and effect how things grow, or live by altering the molecular processes (Schecter, et al. 1995).

According to the Encyclopedia Brittanica, "The toxicity of dioxin renders it capable of killing some species of newborn mammals and fish at levels of five parts per trillion (or one ounce in six million tons). Less than two millionths of an ounce will kill a mouse. Its toxic properties are enhanced by the fact that it can pass into the body through all major routes of entry, including the skin (by direct contact), the lungs (by inhaling dust, fumes or vapors), or through the mouth. Entry through any of these routes contributes to the total body burden"( Dioxin disables cell receptors by binding to them, and is transported to the nucleus of a cell where it causes drastic change in cellular processes (Ibid.)

The majority of studies dealing with dioxin levels in Vietnam have focused on the medical issues and presently, environmentally based research regarding dioxins are inconclusive. What is known, however, is the toxicity of the dioxin itself and with a half-life measured in decades, dioxins in the environment are known to persist in soil and water channels. Many groups have alleged that chemical manufacturers had known about the effects of dioxin, but it took over two decades before attention focused on its toxicity ( /).

During the Vietnam War, numerous defoliant compounds were used to strip the Viet Cong of their natural protective cover. The herbicides were shipped in 55-gallon drums that were identified by 4 inch colored bands. The most famous and well known herbicide used during the period was Agent Orange, the compound mixture of 2,4-D and 2,4,5-T. Agent Orange, however was just one of the many other toxic chemicals used. Agent White and Agent Purple were also used with Agent Blue, an arsenic compound comprised of "sodium salt [sic] of cacodylic acid." Although it is not as harmful as other forms of arsenic, a single ounce or more of Agent Blue could kill both animals and humans ( The long term effects of the 2,161,169 gallons of Agent Blue used on Vietnam between 1965 and 1971 cannot be fairly ascertained (Ibid).

Most of the herbicide spraying in Vietnam was done by airplanes rigged with 1000 gallon high pressured pumps which would force the herbicides through spray booms attached on the wings. Defoliation missions were usually flown in a five-plane formation accompanied by helicopter gunships (Ibid). Spraying missions were not confined to aircraft. Herbicides were often dumped from trucks, sprayed by hand, and dispensed by navy boats along riverbanks (Arison, 1995). Begun in 1962 the defoliation program, code named operation Hades easily deforested over 9,000 acres of mangrove forests and successfully defoliated 95% of the planned area ( The success of Hades prompted implementation of operation Ranch Hand, a more emcompanssing extension of the original deforestation program.  

The same herbicides used in Vietnam were also used by farmers in the United States. However, the US formulations were heavily diluted. Herbicide use in the forests of Vietnam were not diluted, rather they were 6-25 times the concentration recommended by the manufacturer. Between 1961-1971 19,395,369 million gallons of herbicides were used in Vietnam which amounts to 5193 gallons daily. During the same period, "the US sprayed enough herbicides to cover 30,305 square miles or 23.8% of the total area of Vietnam with one spraying" (Arison, 1995).

The amounts of defoliants used in Vietnam increased drastically following the first year, from 15,000 gallons in 1962 to 2.28 million in 1966 ( Studies on the use of herbicides in Vietnam showed that within a week of application, plants in the plantation exhibited drastic levels of defoliation. Moreover, the affects of herbicides were visible some 500 yards away from the spray site due to chemical drift. In fact, the vapors of the chemicals used in Vietnam were strong enough to defoliate 6 miles away from the actual spray site. One of the main goals of the defoliation program was to inhibit the access of food for the enemy. According to government documents, herbicides were often used in populated areas and dumped into water supplies and streams

Not everyone in the decision making process agreed with the defoliation plan. Two reports from the Rand Corporation outlined the advantages and disadvantages of operation Ranch Hand. Ranch Hand was implemented to reduce the possibility of ambushes and create food shortages. Yet the program had insignificant impact on enemy food supplies, destroyed the rural south Vietnamese rice crops, and roused much hostility towards the US (Arison, 1995). For the most part, peasant farmers bore the brunt of the defoliation program. In the main war zones of South Vietnam, "semi-dedicious forests have been severely affected. The regeneration of these forests could be seriously retarded by repeated applications of herbicides (www.

Moreover, the high levels of dioxin in the chemicals have been linked to serious ailments. "Researchers have found that during the spraying of Agent Orange in southern Vietnam, dioxin levels in human tissues were as high as 900 times greater in Vietnamese living in South Vietnam than those living in North Vietnam where Agent Orange was not used...citizens in southern Vietnam may be at a greater risk of cancers, adverse reproductive and development effects, and immune deficiency" (Arison, 1995).

In laboratory studies, tests using 2 parts of dioxin per trillion (ppt) in lab animals would cause stillbirths and death. In comparison, US servicemen returning from Vietnam had 50 ppt or more in their bloodstream ( Although research on the effects of Agent Orange have been inconclusive because of inherent biases in sampling, a 1986 study conducted by the National Cancer Institute showed that "farmers who were exposed to 2,4-D an ingredient in Agent Orange, showed...six times more non-Hodgkin's lymphomas than farmers not exposed" (Ibid). Additionally, Marines who were on active duty during the defoliation program had a 110% higher rate of the same disorder (Ibid).

The dioxin TCDD has been found in soil, dust, soot and residually in gull eggs and river fishes. Dioxin easily accumulates in fish tissue and as the fish are ingested by people or wildlife, the dioxin is directly transferred. This is a serious problem because the dioxin is believed to be the cause of many human diseases including cancer.

TCDD can be broken down in component parts by light but in places that are impenetrable, TCDD can remain indefinitely (Tshirley, 1986). In soil for example, TCDD can be found 10 or more years after its application. In research areas using sandy soil, TCDD was found in the upper 15 centimeters of the soil when it was applied 12 years earlier (Ibid). The persistence of the dioxin in the soil and water creates a toxic environment for Vietnam's animals and population and the effects of the herbicide itself on the environment is devastating.

Once a green and lush countryside, Vietnam during the war period was drastically deforested and contaminated. Leaving aside the disastrous affects of massive bombing attacks, defoliation and destruction of Vietnam's mangrove forests has affected the ecosystem. Of the vegetation damaged most in the Ranch Hand project, 54% of mangroves were exterminated by herbicides (Pfeiffer, 1990). Mangrove forests have low tolerances of chemical defoliants and can usually be killed with one application. The mangroves in Vietnam act as a barrier between the continent and the sea because mangrove roots grow above soil and intertwine to create a solid mass. In mature forests, the roots prevent erosion of the soil due to wind, current or tide.

Mangroves are also special plants because they have membranes that internally filter water, thus they can survive in brackish or salt water. When mangrove leaves fall, they decompose and support a wide variety of invertebrates (Ibid). Local Vietnamese farmers also often utilize mangrove forests for various seafood, tannin for leather, and charcoal for cooking.

Once herbicidal spraying began in Vietnam, the mangroves and the ecosystem it supported crumbled. Typical mangrove forests are home to about 80 species of birds, and after the defoliation program only a handful were present. Furthermore, the wide scope of aquatic life usually found in these environments were near non- existent. "One species of mollusk may have been placed in danger of extinction by Agent Orange. The number and variety of planktonic and benthic well as fish eggs, also declined" (Ibid).

Mangroves were barriers between land and sea, and their extermination led to increased soil erosion. Currents or wakes from the sea have eroded almost 6 inches of soil in certain areas (Pfeiffer, 1990). Regeneration of the forest area may also prove difficult. Invertebrates, such as crabs, usually feed off the nutrients of decomposing mangrove leaves. But with most of the leaves gone, the crabs now feed on delicate mangrove seedlings. To make matters worse, defoliation of the mangroves and the increased levels of decomposing leaves created a tremendous boom in the crab population. The effects of chemical herbicides and their byproducts have created ecological problems in Vietnam that may take decades to correct. The introduction of the chemical arsenal into the Vietnam war has proved disastrous on man as well as environment.

3. Duration: 1961-75

4. Location
Continent: Asia
Region: East Asia
Country: Vietnam

5. Actors: USA, Laos, Cambodia, Vietnam, Soviet Union, China, Korea, Australia

II. Environment Aspects

6. Type of Environmental Problem: Pollution Land

7. Type of Habitat: Tropical

8. Act and Harm Sites:

III. Conflict Aspects

9. Type of Conflict: Interstate

10. Level of Conflict: High

11. Fatality Level of Dispute: 1,000,000

III. Environment and Conflict Overlap

12. Environment-Conflict Link and Dynamics: Indirect

13. Level of Strategic Interest: Multilateral

14. Outcome of Dispute: Victory

IV. Related Information and Sources

15. Related ICE Cases

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16. Relevant Websites and Literature

Browne, Malcolm. "War and The Environment" Audubon. Vol.93 Sept./Oct. 1991.
Pfeiffer, E.W. "Degreening Vietnam" Natural History. Nov,1990. pp.37-40.
Raloff, Janet. "Dioxin's 'Fingerprint' Lingers for Decades" Science News Vol. 130, Oct. 4, 1986. p.212.
Science News. "Ranch Hand's Dioxin Legacy" Science News. Vol. 133, June 11, 1988.
Schecter, Arnold. et al. "Agent Orange and the Vietnamese: The Persistence of Elevated Dioxin Levels in Human Tissues." The American Journal of Public Health. Vol. 84 No. 4, April 1995.
Tshirley, Fred. "Dioxin" Scientific American Vol.254 Feb. 1986. pp.29-35. "Defoliation: Agent Orange" "The Story of Agent Orange." Staff Report, US Veteran News and Report. "Studying the Effects of Agent Orange in Vietnam" "Agent Orange and Related Issues." Released May 28 [sic].

December, 1997