DA NANG, Vietnam (AP) — The Vietnam War ended on April 30, 1975, when the South Vietnamese capital of Saigon fell to Communist forces. But millions of people still face daily battles with its chemical legacy.

Nguyen Thanh Hai, 34, is one of millions with disabilities linked to Agent Orange. Born with severe developmental challenges, it's a struggle for him to complete tasks others take for granted: buttoning the blue shirt he wears to a special school in Da Nang, practicing the alphabet, drawing shapes or forming simple sentences.

Hai grew up in Da Nang, the site of a U.S. air base where departing troops left behind huge amounts of Agent Orange that have lingered for decades, leeching into food and water supplies in areas like Hai's village and affecting generations of residents.

Across Vietnam, U.S. forces sprayed sprayed 72 million liters (19 million gallons) of defoliants during the war to strip the enemy's cover. More than half was Agent Orange, a blend of herbicides.

Agent Orange was laced with dioxin, a type of chemical linked to cancer, birth defects and lasting environmental damage. Today, 3 million people, including many children, still suffer serious health issues associated with exposure to it.

Vietnam has spent decades cleaning up the toxic legacy of the war, in part funded by belated U.S. assistance, but the work is far from complete. Now, millions in Vietnam are worried that the U.S. may abandon Agent Orange cleanup as President Donald Trump slashes foreign aid.

Decades of contamination

When the war ended, the U.S. turned its back on Vietnam, eager to turn the page on a painful chapter in its history.

But Vietnam was left with dozens of dioxin hotspots spread across 58 of its 63 provinces.

Vietnam says the health impacts last generations, threatening the children, grandchildren, and even great-grandchildren of people exposed to the chemicals with health complications ranging from cancer to birth defects that affects the spine and nervous system.

But the science about the human health impact — both to those exposed to Agent Orange and the generations that follow — remains unsettled. This is partly because when the two countries finally started working together in 2006, they focused on finding dioxin in the environment and clearing it instead of studying the still-contentious topic of its impact on human health, said Charles Bailey, co-author of the book “From Enemies to Partners: Vietnam, the U.S. and Agent Orange.”

“The science of causality is still incomplete,” said Bailey.

Vietnam identifies Agent Orange victims by checking family history, where they lived, and a list of health problems linked to the poison. And Hai's disabilities were very likely linked to the spraying of the defoliant, added Bailey.

The 34-year-old dreams of becoming a soldier like his grandfather, was unable to leave home for years, waiting alone while his family went out to work. It was only five years ago that he began attending a special school. “I am happy here because I have many friends,” he said. Other students at the school hope to become tailors or makers of incense sticks.

The contamination also denuded Vietnam’s natural defenses. Nearly half of its mangrove trees, which shield shores from strong storms, were destroyed. Much of its tropical forest was irrevocably damaged, while the herbicide also leached the soil of nutrients in some of Vietnam’s most climate-vulnerable areas.

A massive cleanup begins

In the decades after the war ended, the recovering country fenced off heavily contaminated sites like Da Nang airport and began providing support to impacted families.

But the U.S. largely ignored growing evidence of health impacts — including on its own veterans — until the mid-2000s, when it and began funding cleanup in Vietnam. In 1991, the U.S. recognized that certain diseases could be related to exposure to Agent Orange and made veterans who had them eligible for benefits.

Since 1991, it has spent over $155 million to aid people with disabilities in areas affected by Agent Orange or littered by unexploded bombs, according to the U.S. State Department. The two countries have also cooperated to recover war dead, with the U.S. aiding Vietnam's search for its own missing.

Cleaning up Agent Orange is expensive and often dangerous. Heavily polluted soil needs to be unearthed and heated in large ovens to very high temperatures, while less contaminated soil can be buried in secure landfills.

Despite years of work, large sites still need to cleared. In Da Nang, where an air base was contaminated during storage and transportation of Agent Orange, the U.S. completed a $110 million cleanup in 2018 but an area the size of 10 soccer fields still remains heavily contaminated.

Cooperation on war legacy issues also laid a foundation for growing U.S.-Vietnam ties, culminating in 2023 when Vietnam elevated the U.S. to its highest diplomatic status of comprehensive strategic partner.

"The United States considers Vietnam a key partner in advancing a free and open Indo-Pacific," former U.S. Treasury Secretary Janet Yellen said in Vietnam in 2023.

Anxiety about aid cuts

But Donald Trump's cuts to USAID stalled key projects in Vietnam, and while many have resumed, doubts remain about U.S. reliability.

Vietnam now has to negotiate a new reality where the U.S. president says the country can no longer afford to help other countries.

The country can’t handle the toxic chemicals that still persist without help, said Nguyen Van An, the chairman of Association for Victims of Agent Orange in Danang. “We always believe that the U.S. government and the manufacturers of this toxic chemical must have the responsibility to support the victims,” he said.

He said he hoped that any stoppages to ongoing projects due to shifting politics in Washington would be temporary.

Insufficient data means that experts can't definitely say when the risk to human health will end. But the more urgent problem is if that cleanup efforts are interrupted, the now-exposed contaminated soil could get into waterways and harm more people.

A 10-year project to clear the some 500,000 cubic meters (650,000 cubic yards) of dioxin-contaminated soil — enough to fill 40,000 trucks — at Bien Hoa airbase was launched in 2020. It stopped for a week in March and then restarted.

But Bailey, who worked on issues related to the Agent Orange in Vietnam for years, said future USAID funding for the cleanup and a $30 million program for people with disabilities was uncertain.

With federal cuts to USAID, most staffers in Vietnam are expected to be gone by later this year, leaving nobody to administer funding for remediation programs, even if it is not cut itself.

“This basically leaves a very large mountain of contaminated soil. Only 30% of which has been dealt with and that is less contaminated,” said Bailey.

He added that less than half of the soil at Bien Hoa had been treated and much of the remaining soil was heavily contaminated and needed to be treated in an as-yet unbuilt incinerator.

Tim Rieser, who was retired Sen. Patrick Leahy’s foreign policy aide when the Vermont Democrat secured the original funding for Vietnam War remediation projects and is now a senior advisor to Sen. Peter Welch, said Congress still supports the programs but it would be hard for them to continue without staff.

"For more than 30 years, the U.S. and Vietnam have worked together to rebuild relations by dealing with the worst legacies of the war, like Agent Orange,” he said. “Now the Trump administration is mindlessly shutting everything down, with no concern for the impact of their actions on relations with an important partner in the Indo-Pacific.”

The U.S. embassy in Hanoi didn't respond to a request for comment.

Chuck Searcy, an American Vietnam War veteran who has worked on humanitarian programs in the country since 1995, said he worries that trust built over years could erode very rapidly. He pointed out that those who benefit from U.S. funded projects to address war legacies are “innocent victims.”

“They’ve been victimized twice, once by the war and the consequences that they’ve suffered. And now by having the rug pulled out from under them,” he said.

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Associated Press journalist David Rising in Bangkok contributed to this report.

FILE- Armored personnel carriers with tank support move through dense underbrush with a payload of South Vietnamese infantrymen and U.S. cavalrymen during patrol through jungle 40 miles northeast of Saigon on June 5, 1969. (AP Photo/Rick Merron, File)

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FILE- Infantryman points out a suspicious shadow in a tree to his machine gunner as they move on patrol near the Cambodian Border west of Pleiku in Vietnam on Nov. 26, 1966. Troops of the 25th Infantry Division (1st Battn. 14th Inf.) inches through the thick jungle from their base camp after being held up three days by snipers. AP Photo/Horst Faas, File)

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FILE- A yellow flag marks a field contaminated with dioxin near Danang airport, during a ceremony marking the start of a project to clean up dioxin left over from the Vietnam War, at a former U.S. military base in Danang, Vietnam Thursday Aug. 9, 2012. (AP Photo/Maika Elan, File)

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FILE- Maps of the area contaminated with dioxin around Danang airport are displayed during a ceremony marking the start of a project to clean up dioxin left over from the Vietnam War, at a former U.S. military base in Danang, Vietnam Thursday Aug. 9, 2012. (AP Photo/Maika Elan, File)

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FILE -A woman walks next to a highly contaminated pond around the grounds of the Danang airbase in Danang, Vietnam, May 21, 2007. (AP Photo/David Guttenfelder, File)

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Truong Minh Phu, 20, centre, sits in a classroom with other students at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Aniruddha Ghosal)

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A boy smiles looking out of the window at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Aniruddha Ghosal)

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Nguyen Thanh Hai, 34, reacts after getting compliments on his work during class at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Hau Dinh)

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Nguyen Van Quoc Hung, 13, plays with building blocks at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Hau Dinh)

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Students exercise and play with wooden blocks in physiotherapy class at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Hau Dinh)

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A student plays with a wooden shape sorter at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Hau Dinh)

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A student sweeps the area in front of a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Aniruddha Ghosal)

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FILE- Attendants sit next to a field contaminated with dioxin before a ceremony marking the start of a project to clean up dioxin left over from the Vietnam War, at a former U.S. military base in Danang, Vietnam Thursday Aug. 9, 2012. (AP Photo/Maika Elan, File)

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FILE- A Vietnamese soldier stands guard in front of military aircraft near a dioxin contaminated area while U.S. Defense Secretary Jim Mattis visits Bien Hoa air base in Bien Hoa, outside Ho Chi Minh City, Vietnam, Oct. 17, 2018. (Kham/Pool Photo via AP, File)

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FILE- A Vietnamese worker sprays water over stones to be used in the construction of a silo for storing soil contaminated with Agent Orange dioxide at the site of a former American airbase in Danang, Vietnam on Wednesday, April 24, 2013. (AP Photo/Hau Dinh, File)

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Students put on uniforms at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Hau Dinh)

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A girl who has health problems because of exposure to Agent Orange practices sewing at a special school In Da Nang, Vietnam, March 7, 2025. (AP Photo/Aniruddha Ghosal)

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Students attend a physiotherapy class at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Hau Dinh)

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Truong Minh Phu, 20, practices with an arm pedal exerciser in physiotherapy class at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Hau Dinh)

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A student fills a colouring book at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Aniruddha Ghosal)

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Nguyen Thanh Hai, 34, centre, raises his hand to answer question during class at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Hau Dinh)

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Nguyen Khanh Vy, 19, smiles while writing in her book at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Aniruddha Ghosal)

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Nguyen Ba Quy Phuoc, 14, attends a physiotherapy class at a school for victims of Agent Orange in Da Nang, Vietnam, March 7, 2025. (AP Photo/Hau Dinh)

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