50 years later, Vietnam’s environment still bears the scars of war

When the Vietnam War finally ended on April 30, 1975, it left behind a landscape scarred with environmental damage. Vast stretches of coastal mangroves, once housing rich stocks of fish and birds, lay in ruins. Forests that had boasted hundreds of species were reduced to dried-out fragments, overgrown with invasive grasses.

The term “ecocide” had been coined in the late 1960s to describe the US military’s use of herbicides like Agent Orange and incendiary weapons like napalm to battle guerrilla forces that used jungles and marshes for cover.

Fifty years later, Vietnam’s degraded ecosystems and dioxin-contaminated soils and waters still reflect the long-term ecological consequences of the war. Efforts to restore these damaged landscapes and even to assess the long-term harm have been limited.

As an environmental scientist and anthropologist who has worked in Vietnam since the 1990s, I find the neglect and slow recovery efforts deeply troubling. Although the war spurred new international treaties aimed at protecting the environment during wartime, these efforts failed to compel post-war restoration for Vietnam. Current conflicts in Ukraine and the Middle East show that these laws and treaties still aren’t effective.

Agent Orange and daisy cutters

The US first sent ground troops to Vietnam in March 1965 to support South Vietnam against revolutionary forces and North Vietnamese troops, but the war had been going on for years before then. To fight an elusive enemy operating clandestinely at night and from hideouts deep in swamps and jungles, the US military turned to environmental modification technologies.

The most well-known of these was Operation Ranch Hand, which sprayed at least 19 million gallons (75 million liters) of herbicides over approximately 6.4 million acres (2.6 million hectares), of South Vietnam. The chemicals fell on forests, and also on rivers, rice paddies, and villages, exposing civilians and troops. More than half of that spraying involved the dioxin-contaminated defoliant Agent Orange.

Four United States Air Force Ranch Hand C-123s spray a Viet Cong jungle position near here with a defoliating liquid. The four specially equipped aircraft cover a swath of more than 1,000 feet wide on each pass over the dense jungle.

Credit: Bettmann via Getty Images

Herbicides were used to strip the leaf cover from forests, increase visibility along transportation routes and destroy crops suspected of supplying guerrilla forces.

As news of the damage from these tactics made it back to the US, scientists raised concerns about the campaign’s environmental impacts to President Lyndon Johnson, calling for a review of whether the US was intentionally using chemical weapons. American military leaders’ position was that herbicides did not constitute chemical weapons under the Geneva Protocol, which the US had yet to ratify.

Scientific organizations also initiated studies within Vietnam during the war, finding widespread destruction of mangroves, economic losses of rubber and timber plantations, and harm to lakes and waterways.

In 1969, evidence linked a chemical in Agent Orange, 2,4,5-T, to birth defects and stillbirths in mice because it contained TCDD, a particularly harmful dioxin. That led to a ban on domestic use and suspension of Agent Orange use by the military in April 1970, with the last mission flown in early 1971.

Incendiary weapons and the clearing of forests also ravaged rich ecosystems in Vietnam.

The US Forest Service tested large-scale incineration of jungles by igniting barrels of fuel oil dropped from planes. Particularly feared by civilians was the use of napalm bombs, with more than 400,000 tons of the thickened petroleum used during the war. After these infernos, invasive grasses often took over in hardened, infertile soils.

“Rome Plows,” massive bulldozers with an armor-fortified cutting blade, could clear 1,000 acres a day. Enormous concussive bombs, known as “daisy cutters”, flattened forests and set off shock waves killing everything within a 3,000-foot (900-meter) radius, down to earthworms in the soil.

The US also engaged in weather modification through Project Popeye, a secret program from 1967 to 1972 that seeded clouds with silver iodide to prolong the monsoon season in an attempt to cut the flow of fighters and supplies coming down the Ho Chi Minh Trail from North Vietnam. Congress eventually passed a bipartisan resolution in 1973 urging an international treaty to prohibit the use of weather modification as a weapon of war. That treaty came into effect in 1978.

The US military contended that all these tactics were operationally successful as a trade of trees for American lives.

Despite Congress’ concerns, there was little scrutiny of the environmental impacts of US military operations and technologies. Research sites were hard to access, and there was no regular environmental monitoring.

Recovery efforts have been slow

After the fall of Saigon to North Vietnamese troops on April 30, 1975, the US imposed a trade and economic embargo on all of Vietnam, leaving the country both war-damaged and cash-strapped.

Vietnamese scientists told me they cobbled together small-scale studies. One found a dramatic drop in bird and mammal diversity in forests. In the A Lưới valley of central Vietnam, 80 percent of forests subjected to herbicides had not recovered by the early 1980s. Biologists found only 24 bird and five mammal species in those areas, far below normal in unsprayed forests.

Only a handful of ecosystem restoration projects were attempted, hampered by shoestring budgets. The most notable began in 1978, when foresters began hand-replanting mangroves at the mouth of the Saigon River in Cần Giờ forest, an area that had been completely denuded.

Mangroves have been replanted in the Cần Giờ Biosphere Reserve near Ho Chi Minh City, but their restoration took decades.

Credit: Tho Nau/Flickr

In inland areas, widespread tree-planting programs in the late 1980s and 1990s finally took root, but they focused on planting exotic trees like acacia, which did not restore the original diversity of the natural forests.

Chemical cleanup is still underway

For years, the US also denied responsibility for Agent Orange cleanup, despite the recognition of dioxin-associated illnesses among US veterans and testing that revealed continuing dioxin exposure among potentially tens of thousands of Vietnamese.

The first remediation agreement between the two countries only occurred in 2006, after persistent advocacy by veterans, scientists, and nongovernmental organizations led Congress to appropriate US$3 million for the remediation of the Da Nang airport.

That project, completed in 2018, treated 150,000 cubic meters of dioxin-laden soil at an eventual cost of over $115 million, paid mostly by the US Agency for International Development, or USAID. The cleanup required lakes to be drained and contaminated soil, which had seeped more than 9 feet (3 meters) deeper than expected, to be piled and heated to break down the dioxin molecules.