For minimum wage or less, they blasted open seams, built wooden beam supports in the mine shafts, and dug out ore pieces with picks and wheelbarrows. The shafts penetrated as deep as 1,500 feet, with little or no ventilation. The bitter-tasting dust was all pervasive, coating their teeth. They ate in the mines and drank water that dripped from the walls and, sometimes, developed chronic coughs. And much worse.

Native American uranium miners were essential to the United States’ efforts to create a nuclear arsenal. From the late 1940s to the early 1970s, Indian people dug up approximately four million tons of uranium ore—nearly a quarter of the total national underground production in the United States used in nuclear weapons. As they did so, they were sent into harm’s way without sufficient warning, becoming the workers most severely exposed to ionizing radiation in the US nuclear weapons complex. After more than a century, the legacy of US uranium mining lingers. More than three billion metric tons of mining and milling wastes were generated in the United States. Today, Navajos still live near about one third (approximately 1,200 out of 4,000) of all abandoned uranium mines in the United States.

Only after concerted efforts by Navajo activists to spur congressional investigations in 1993 and 2006 did the US government promise to remediate abandoned mines and ascertain their health impacts. But more than a century after the government issued the first uranium mining leases on Navajo land, the Trump administration has proposed deep cuts in the Environmental Protection Agency’s budget—upward of 30 percent overall—putting that cleanup effort in peril.

America’s Indian miners were never warned of the hazards of radioactivity in the mines, where they inhaled, ingested, and drank uranium dust. The water in the mines was especially dangerous; it contained high quantities of radon—a radioactive gas emanating from the ore. Radon decays into heavy, more radiotoxic isotopes, called “radon daughters,” which include isotopes of polonium, bismuth, and lead. The alpha particle emissions of radon daughters are considered to be about 20 times more carcinogenic than x-rays. If they lodge in the respiratory system, especially the deep lung, radon daughters emit energetic ionizing radiation that can damage cells of sensitive internal tissues.

And of course, the miners brought the uranium dust home, along with their contaminated clothing.

A known danger, hidden. The hazards of uranium mining have been known for centuries. As early as 1556, dust in the Ore Mountain (Erzgebirge) mines bordering Germany and what is now the Czech Republic was reported to have “corrosive qualities… it eats away the lungs and implants consumption in the body…” By 1879, researchers found that 75 percent of the miners in the Ore Mountains had died from lung cancer. By 1932, the Ore Mountain miners were receiving compensation for their cancers from the German government. Uranium mining was convincingly linked to lung cancer by dozens of epidemiological and animal studies by the late 1930s.

In 1942, Wilhelm C. Hueper, the founding director of the environmental cancer section of the National Cancer Institute, brought the European studies to light in the United States—concluding that radon gas was responsible for half of the deaths of European miners after 10 to 20 years of exposure. By this time, uranium had become a key element for the making of the first atomic weapons. Hueper’s superiors blocked him from further publication and discussion in this area; they told him that dissemination of such information was “not in the public interest.”

In fact, withholding information about workplace hazards was deeply embedded in the bureaucratic culture of the early nuclear weapons program. In 1994, the Energy Department made a previously secret document, written in the late 1940s, public. It crystallized the long-held rationale for keeping nuclear workers in the dark: “We can see the possibility of a shattering effect on the morale of the employees if they become aware that there was substantial reason to question the standards of safety under which they are working. In the hands of labor unions, the results of this study would add substance to demands for extra-hazardous pay…”

Kee Begay worked in the mines for 29 years and was dying of lung cancer when I first met him. “The mines were poor and not fit for human beings,” he told me. Begay also lost a son to cancer. “He was one of many children that used to play on the uranium piles during those years. We had a lot of uranium piles near our homes—just about 50 or 100 feet away or so. Can you imagine? Kids go out and play on those piles.”

In 1957, the US Public Health Service reported that the average radiation lung dose to Indian miners was 21 times higher than was allowed in the Atomic Energy Commission’s nuclear weapons plants. In 1962, the Public Health Service revealed that radon exposure in the mines was statistically linked to lung cancer among US miners—at a rate comparable to what Heuper had warned about 20 years earlier.

Lung disease associated with radon exposure was “totally avoidable,” former chief health scientist for the AEC Merrill Eisenbud said in 1979. “The Atomic Energy Commission … is uniquely responsible for the death of many men who developed lung cancer as a result of the failure of the mine operators, who must also bear the blame, because they too had the information, and the Government should not have had to club them into ventilating their mines.”

How the Trump budget threatens uranium mine cleanup. Even though there is a significant body of evidence, spanning decades, of deliberate negligence by the US government, federal courts have denied claims by the uranium miners and those exposed to radioactive fallout from Nevada nuclear weapons testing on the grounds of sovereign immunity. “[A]ll the actions of various governmental agencies complained of by plaintiffs were the result of conscious policy decisions made at high government levels based on considerations of political and national security feasibility factors,” is how one federal judge put it.

After several decades of considerable effort by miners and their families, Congress passed the Radiation Exposure Compensation Act in October 1990. The Act offered a formal apology for sending people into harm’s way and provided a one-time compensation to each victim in the amount of $150,000. But the financial compensation came too late for many who had died. And it would never be enough to compensate for illness and death that could have been prevented.

An estimated 30,000 Navajos are now living near abandoned uranium mines. The EPA has found that, because of their traditional lifestyle, Indian people are the group most vulnerable to environmental contaminants. The Navajo nation and the US Justice Department have reached settlement agreements in two uranium-related lawsuits since 2014; the settlements total about $1.5 billion, which would go toward remediating 144 of the most troublesome mines. But there’s a rub: The degree and extent of mine cleanup depends on tribal assistance funds and oversight by the US Environmental Protection Agency (EPA). The budget plan that the Trump administration recently released makes deep cuts in the EPA workforce, in EPA programs to ensure compliance with the cleanup agreements, and in funding for the Navajo nation to carry out its responsibilities to oversee the process. This makes it clear that addressing the sacrifices made by the Indian people for the nuclear arms race are being put at the bottom of the list of Trump administration priorities.