The story of “forever chemicals” often begins in the headlines of the last decade — contaminated water systems, cancer clusters, corporate cover-ups, and a growing sense that something invisible has seeped into every corner of modern life. But the crisis didn’t appear overnight. Its roots stretch back nearly a century, to a moment when chemists racing to build the world’s first atomic bomb stumbled onto materials unlike anything the world had seen before.

In They Poisoned the World: Life and Death in the Age of Forever Chemicals, investigative journalist Mariah Blake traces the full arc of this unfolding catastrophe. Part exposé, part human drama, the book uncovers how PFAS — a vast family of indestructible industrial compounds now found in the blood of nearly every person on Earth — were born in secrecy, promoted as miracles of modern chemistry, and shielded from scrutiny even as early evidence pointed to devastating health impacts. Blake weaves together two timelines: the behind-the-scenes machinations of chemical manufacturers and federal regulators, and the grassroots uprising that emerged decades later when residents of Hoosick Falls, New York, discovered their drinking water was contaminated and refused to stay silent.

The excerpt below comes from early in the book, where Blake traces PFAS’s origin story to the high-stakes laboratories of the Manhattan Project. It’s a glimpse into the frantic wartime research, the industrial acceleration, and the overlooked hazards that laid the foundation for one of the most sweeping public health crises of our time.

This history reminds us that the materials we create — and the systems we entrust to oversee them — shape the world for generations. And understanding how PFAS began is essential to understanding the fight to hold polluters accountable today.

On a clear, hot afternoon in July 1939, a car carrying the esteemed physicists Leo Szilard and Eugene Wigner rumbled up the drive of a humble white cottage on Long Island’s Cutchogue Harbor, the verdant retreat where Albert Einstein was passing his summer. In recent years, scientists around the world had begun experimenting with splitting uranium atoms, a process with the potential to release virtually unlimited energy. Some believed it could also lead to ferocious new weapons. Wigner and Szilard, both Hungarian-born Jews who had studied under Einstein in Berlin before the rise of Adolf Hitler, were convinced that the Nazis were already on the brink of making an atomic bomb. But their desperate efforts to warn U.S. officials had led nowhere, so they decided to approach the one person in their orbit who they believed could get their message through.

Dressed in an undershirt and rolled-up pants, Einstein greeted his old friends and led them to a screened-in porch overlooking a sloping lawn. There, between sips of iced tea, Szilard and Wigner explained the scientific reasons for their fears. In the past, Einstein had voiced skepticism about the chances of harvesting large-scale nuclear energy in the near term. But Wigner and Szilard persuaded him it was possible. Although he was an ardent pacifist, Einstein agreed to help alert the U.S. government to the threat, and on August 2, 1939, a spare two-page letter to President Franklin D. Roosevelt went out under the renowned physicist’s name. It urged the president to speed up experimental work on uranium by underwriting university research and “obtaining the co-operation of industrial laboratories which have the necessary equipment.”

Heeding this warning, the Roosevelt administration began secretly funding research by a team of physicists at Columbia University. The goal was to isolate a rare class of uranium atoms that were capable of producing nuclear chain reactions—the only process that could yield enough energy for an atom bomb. Separating the minuscule particles from the rest of the uranium ore presented mind-bending technical challenges. But the physicists devised several possible methods. The most promising—gaseous diffusion—involved converting uranium into a gas called uranium hexafluoride, or hex, and pumping it through a maze of porous barriers. Since the desired isotope, uranium-235, passed through the tiny pores more easily, the rest of the atoms would gradually be filtered out, leaving only the prized nuclear fuel.

However, because hex also contained fluorine, the infamous Lucifer’s gas, the compound was dangerous to work with and fiercely corrosive, making it extremely difficult to contain. If the project stood any chance of succeeding, the physicists needed materials that could stand up to both fluorine and hex in some of the harshest conditions imaginable.

The Nobel Prize–winning scientist overseeing the uranium program, Harold Urey, suspected that only other compounds containing fluorine would work—specifically those containing fluorine and carbon, which together form the strongest bond in chemistry. Such materials were extremely rare, but Urey managed to track down a few drops of a fluorocarbon liquid, the result of a laboratory accident at Pennsylvania State University. Sure enough, when mixed with the hex, it produced no reaction.

This was a major breakthrough. But making enough uranium for a bomb would require mind-boggling quantities of hex-resistant equipment. Urey’s team would need an assortment of fluorocarbons suited to various purposes. Among the most urgent was a fluorocarbon plastic that could be fashioned into seals and gaskets to keep the enrichment system airtight. As luck would have it, DuPont had already developed one that seemed to fit the bill: Teflon. The company hadn’t figured out how to make more than a few ounces at a time, but it had a history of ramping up production fast.

Urey’s deputy eventually summoned Malcolm Renfrew, the chemist overseeing DuPont’s stalled Teflon program, to Columbia, by then the bustling hub of the bomb project. Without revealing the exact nature of the enterprise, he pleaded for Renfrew’s help. “He told us there was a development now coming on in this country and in Germany which would determine who would win the war, that it was going to be extraordinarily important for us to be participating at our maximum strength,” the chemist recalled. Renfrew would be given a few weeks to prepare, and then DuPont was expected to break ground on a plant that manufactured a million-plus pounds of Teflon per year.

The conversation left Renfrew “popeyed,” as he later recalled. Nevertheless, DuPont agreed to launch a government-funded crash program to figure out how to produce Teflon at scale. A team of chemists and engineers at Renfrew’s lab in Kearny, New Jersey, worked around the clock building a pilot plant. Almost as soon as construction was finished, the plant exploded, killing two young workers. The crew rebuilt it—this time with blast walls and remote controls to handle the most dangerous work. Meanwhile, another DuPont team studying molding techniques discovered that a combination of pressure and extreme heat melded Teflon powder into sheets that could be sliced and sculpted into hex-proof gaskets.

By late 1941, the government was recruiting chemists from venerable institutions like Purdue and Cornell to cultivate other types of fluorocarbons—among them refrigerants, sealants, and lubricants—and overcome the daunting technical barriers to large-scale production. A team from Johns Hopkins worked with DuPont to develop industrial methods for isolating fluorine and manufacturing other previously scarce substances essential for fluorocarbon production. The university scientists weren’t told why their expertise was needed, and the coordination among them was initially haphazard.

That all changed in July 1942. Urey convened a secret meeting with military officials, DuPont executives, and chemists from various universities at Dumbarton Oaks, an august estate in Washington’s Georgetown neighborhood. There, he announced plans to “sponsor closer collaboration” among attendees. The primary goal was to develop a specific class of fluorocarbons whose defining feature was multiple fluorine-carbon bonds, making them virtually indestructible—a group of substances that would later become known as forever chemicals or PFAS. In the interest of speed, participants were told, the government was willing to fund all lines of inquiry simultaneously and pay generously for the resulting materials. (“Dollar cost will be a very small factor,” the meeting minutes noted.)

The event touched off a technological race among project chemists that mirrored the urgent, all-at-once approach to developing nuclear fuels. Because of DuPont’s unrivaled experience with fluorine compounds, it was charged with coordinating their efforts. Chemists at various universities compiled their data into monthly reports for DuPont’s research director, who kept Urey updated and helped rush discoveries into production. In the last two months of 1942 alone, the government contracted with DuPont to build two factories to produce fluorocarbon lubricants and sealants based on research from university scientists, and a third facility to manufacture a chemical critical to the production of both fluorocarbons and hex—which were now a matter of national security.

…

In keeping with the Lewis Committee’s recommendation, this method was now the top priority. While most of the fuel programs were relegated to the pilot-plant phase, work immediately began on a full-scale gaseous diffusion plant. The scope of the operation was breathtaking. Composed of fifty-one interconnected buildings spread over forty-plus acres in rural Tennessee, it housed an elaborate mechanical labyrinth involving hundreds of miles of pipe and tens of thousands of filters, seals, gaskets, and pumps—virtually all of which needed to be hex resistant. To overcome the lingering technical barriers, Urey’s team recruited more chemists. Even with the added government resources, DuPont couldn’t manage to produce Teflon in the quantities needed. [Because Teflon warped under pressure, the modest quantities DuPont did produce weren’t suited to uranium enrichment. But the material found other wartime uses, including as linings for liquid fuel tanks and nose cones for “proximity bombs.”]  But it brought other fluorocarbons from research bench to mass production at a previously unimaginable speed. By late 1943, DuPont had more than a thousand workers and several factories pumping out tens of thousands of pounds of these substances at its Chambers Works site in Deepwater, New Jersey.

Fluorocarbons were hardly the only substances undergoing rapid development during this period. Faced with shortages of natural materials like steel and rubber, in 1941 the board overseeing U.S. military provisions had called for substituting plastics whenever possible. The government had since spent huge sums developing synthetic materials and expanding the assembly lines of DuPont and other companies so they could produce the quantities needed for global warfare. As a result, onetime laboratory curiosities like synthetic rubber and polyethylene were suddenly being produced in massive quantities and fashioned into everything from bazooka barrels and parachutes to fighter-plane windshields. Charles Stine marveled at the fruits of this unprecedented collaboration between industry and government in a speech before the American Chemical Society: “The pressures of this war are compressing into the space of months developments that might have taken us a half-century to realize.”

But while most of the new synthetics grew out of established branches of chemistry, fluorocarbons were a virgin frontier mined with poorly understood hazards, and the frenzied pace left little time for developing safeguards. At DuPont’s Chambers Works, the dangers of the fluorocarbon processing areas were legendary. Fires and explosions were commonplace; employees were regularly hospitalized with breathing problems, chemical burns, or worse. Manhattan Project inspectors warned their supervisors that widespread fear of injury was leading to unrest among workers and that DuPont employees had come to dread an assignment there as “an exile to Devil’s Island.”

Excerpted from THEY POISONED THE WORLD by Mariah Blake. Copyright © 2025 by Mariah Blake. Published in the United States by Crown, an imprint of the Crown Publishing Group, a division of Penguin Random House LLC. All rights reserved.