In mid-February, Trump administration leaders received a desperate warning from their diplomats posted in Vietnam, one of the most important American partners in Asia.

Workers were in the middle of cleaning up the site of an enormous chemical spill, the Bien Hoa air base, when Secretary of State Marco Rubio abruptly halted all foreign aid funding. The shutdown left exposed open pits of soil contaminated with dioxin, the deadly byproduct of Agent Orange, which the American military sprayed across large swaths of the country during the Vietnam War. After Rubio’s orders to stop work, the cleanup crews were forced to abandon the site, and, for weeks, all that was covering the contaminated dirt were tarps, which at one point blew off in the wind.

And even more pressing, the officials warned in a Feb. 14 letter obtained by ProPublica, Vietnam is on the verge of its rainy season, when torrential downpours are common. With enough rain, they said, soil contaminated with dioxin could flood into nearby communities, poisoning their food supplies.

Hundreds of thousands of people live around the Bien Hoa air base, and some of their homes abut the site’s perimeter fence, just yards from the contaminated areas. And less than 1,500 feet away is a major river that flows into Ho Chi Minh City, population 9 million.

“Simply put,” the officials added, “we are quickly heading toward an environmental and life-threatening catastrophe.”

They received no response from Washington, according to three people familiar with the situation.

Instead, Rubio and Peter Marocco, another top Trump appointee, have not only ordered the work to stop, but they also have frozen more than $1 million in payments for work already completed by the contractors the U.S. hired. The company overseeing the project is Tetra Tech, a publicly traded consulting and engineering firm based in the U.S., and a Vietnamese construction firm has been tasked with the excavation work.

Then, on Feb. 26, Rubio and Marocco canceled both companies’ contracts altogether before apparently reversing that decision about a week later, agency records show. As of Thursday, the companies had not been paid.

The Trump administration has told the courts repeatedly that its process to dismantle the U.S. Agency for International Development, which manages the project’s funds, has been careful and considered. But the botched situation at Bien Hoa is a stark example of the whiplash, conflicting messages and dire consequences that aid organizations worldwide have faced since early February.

Now, after losing several weeks because of the administration’s orders, the companies are scrambling — at their own expense — to secure the Bien Hoa site before it starts raining, according to documents reviewed by ProPublica and several people familiar with the current situation.

The USAID officials who would typically travel to the air base to provide oversight have been placed on administrative leave or prevented from traveling to check on the work. They’ve also been forbidden from communicating with the Vietnamese government or the companies working at the base, sources say, though they believe that directive was lifted after the contracts were recently reinstated. The confusion has left many at both the embassy and in Washington in the dark about where the situation stands.

To ascertain the current status of the work, ProPublica hired a reporter to visit the air base on Friday.

Workers are laboring in 95 degree heat, surrounded by toxic soil. The site has a skeleton crew of less than half of what they previously had, according to workers and documents reviewed by ProPublica. Some staffers found new jobs during the suspension. People working at the site told the reporter they are worried about completing the work before the rainy season descends and are terrified the U.S. will pause the work again.

Since 2019, the U.S. government has collaborated with Vietnam’s Ministry of Defense to clean up the Bien Hoa air base and agreed to spend more than $430 million for the project. Unlike other foreign aid programs, addressing Agent Orange is more akin to restitution than charity because the U.S. brought the deadly substance there in the first place. “The dioxin remediation program is one of the core reasons why we have an extraordinary relationship with Vietnam today,” a State Department official told ProPublica, “a country that should by all rights hate us.”

With enough contaminated soil to fill about 40,000 dump trucks, the Bien Hoa air base is the largest deposit of postwar pesticides remaining in Vietnam after a decadeslong cleanup campaign. Human rights groups, environmentalists and diplomats consider the cleanup work — along with disability assistance that the U.S. has provided to Agent Orange victims across the country — to be one of the most successful foreign aid initiatives of all time.

All of that was now in peril, the officials wrote in their Feb. 14 letter to USAID officials in Washington. “What immediate actions can be taken to avert a potential life-threatening incident while still maintaining compliance with the Executive Order and the suspension directives?” the officials wrote.

U.S. officials in Vietnam grew increasingly panicked. The ambassador sent a diplomatic cable to Washington, and Congress and USAID’s inspector general each received a whistleblower complaint, multiple people told ProPublica.

“Halting a project like that in the middle of the work, that’s an environmental crime,” said Jan Haemers, CEO of another organization that previously worked in Vietnam to clean up Agent Orange in the soil. “If you stop in the middle, it’s worse than if you never started.”

The State Department said in a statement that the contracts at Bien Hoa are “active and running” but did not respond to detailed follow-up questions. Tetra Tech and the Vietnamese construction firm did not respond to questions for this story. The Vietnamese Embassy and Ministry of Defense did not return requests for comment. But the Vietnamese Ministry of Foreign Affairs made a statement on Feb. 13 that it was “deeply concerned” about USAID program suspensions, specifically mentioning the Bien Hoa project.

Trump’s aides, including billionaire Elon Musk, began dismantling the U.S. foreign assistance system almost immediately after the inauguration. They dismissed USAID staff en masse, issued sweeping stop-work orders, froze funds and eventually canceled most of the agency’s contracts with aid organizations around the world, leaving countless children, refugees and other desperately vulnerable people without critical services.

On Monday, Rubio boasted on X that they had cut 83% of USAID’s programs because they didn’t align with Trump’s agenda.

After terminating the contracts, Rubio, Musk and Marocco reversed several of their decisions in Vietnam, designating the Bien Hoa project as one of the few programs to survive, at least for now.

Every president since George W. Bush — including Trump — has made good on the American promise to repair relations with Vietnam by cleaning up Agent Orange and helping those sick or disabled from dioxin poisoning. In 2017, Trump landed at Danang Airport, a prior cleanup site, ahead of a free-trade meeting with Asia-Pacific countries. The U.S. now conducts $160 billion in annual commerce with Vietnam, which has also become a key partner against China’s growing influence in the South China Sea. The Pentagon and Vietnamese military now work together as well, including efforts to locate the remains of soldiers missing in action from the war 50 years ago.

“All of this is underpinned by the cooperation on Agent Orange,” said Charles Bailey, a former Ford Foundation representative in Vietnam who co-wrote a book on the country’s relations with the U.S. in the wake of the war. “It’s like pulling out one or two legs of the stool.”

The Bien Hoa project was formally launched and initial contracts signed during Trump’s first presidency. In another example of the administration’s confusing stance toward the project, Defense Secretary Pete Hegseth told his Vietnamese counterpart on a Feb. 7 phone call that Trump wanted to enhance defense ties by addressing war legacy issues, which include Agent Orange remediation. About half of the project’s funding comes from the Pentagon’s budget, though it’s funneled through USAID, so it was also caught up in the foreign aid freeze.

Environmental consultants, foreign policy experts and government officials said the episode in Bien Hoa shows the administration did not do a thoughtful audit. “One might imagine a less reckless government looking at what we’re doing carefully and then deciding what’s in our interest,” David Shear, a former U.S. ambassador to Vietnam under Barack Obama, told ProPublica.

“But,” he said, “this is government reform by meat cleaver.”

The mixture known as Agent Orange is a combination of two herbicides that the U.S. brought to Vietnam in huge volumes to kill off jungles and mangroves that hid opposition forces during the Vietnam war. The mixture contained dioxin, a deadly substance that not only causes a range of cancers and other illnesses, but is also linked to birth defects for babies exposed in utero. During the war, the U.S. sprayed more than 10 million gallons of the herbicides across vast swaths of the country, exposing U.S. soldiers as well as millions of Vietnamese people and their future children to the deadly toxic substance.

Storage sites like the air bases of Danang and Bien Hoa were heavily contaminated as barrels leaked, broke or were otherwise mishandled. Over the decades, dust has blown the contaminated soil off the bases and abundant rains have pushed the dioxin into waterways and the densely packed surrounding neighborhoods, contaminating fish as well as ducks and chicken that people raise for food. Soil samples at the Bien Hoa base have shown dioxin at levels as high as 800 times the allowed amount in Vietnam.

For decades since the war, and despite extensive documentation of higher rates of cancers and birth defects among people who had been exposed to the chemicals, the U.S. denied the mass toll Agent Orange had taken on Vietnamese people — as well as on American veterans, as ProPublica has previously reported. But starting in the mid-2000s under President George W. Bush, the U.S. began earmarking federal dollars for dioxin remediation in Vietnam to clean up the contamination sites and the two nations’ troubled relationship.

The cleanup work is dangerous and laborious. People hired by the contractors wear extensive protective equipment in the sweltering humidity and must have their blood tested regularly for dioxin. When levels get too high, they are no longer allowed to work at the site. There are supposed to be extensive safety checks in place to ensure the dirt doesn’t poison military officials or the surrounding community.

The plan at Bien Hoa is to excavate a half-million cubic meters of the most contaminated soil and enclose it underground or cook it in an enormous furnace, which hasn’t been built yet, until the dioxin no longer poses a threat. The work requires extensive pumping and management of dioxin-contaminated water. Contractors are halfway through a 10-year project set to happen in stages, and the bulk of the excavation work must be done between December and April when there is less rain.

After Rubio first issued sweeping stop-work orders to aid organizations and contractors around the world in late January, workers from the site were told to stay home for weeks. The companies stopped receiving money to cover payroll and their past invoices. Huge mounds of tarp-covered dirt dotted sections of the base.

USAID and State Department staff scrambled to get the project back online through the State Department’s confusing waiver process and appealed to counterparts in the U.S. A group of Democratic senators sent a letter to Hegseth and Rubio urging them to pay the contractors. “It would be difficult to overstate the damage to the relationship that would result if the U.S were to walk away from these war legacy programs,” they wrote. They got no response.

One of the senators who signed the letter, Jeff Merkley, D-Ore., told ProPublica that abandoning the Bien Hoa cleanup is “a betrayal of the goodwill our two nations built over 30 years” and a “gift to our adversaries.”

Even off-season rains pushed the sites to the brink, two sources said, with water pooling up to the edge of protective aprons, threatening to spill out onto an active military runway after recent rainstorms.

Heavier rains typically start in April before the downpours of the rainy season in May.

The contractors are desperately trying to secure the contaminated dirt and pits before then, according to interviews this week with several people working there. But they are two months behind schedule.

“The problem is that the Trump administration has destroyed USAID, so it’s very unclear how we’re going to complete this project,” said Tim Rieser, a longtime aide to former Sen. Patrick Leahy, D-Vt., who led a bipartisan delegation to break ground in Bien Hoa in 2019. “The people making the decisions probably know the least.”