How Alice Hamilton Waged a One-Woman Campaign to Get the Lead Out of Everything

One day in March of 1911—the same month as the infamous Triangle shirtwaist factory fire in New York City that trapped and killed 146 workers—a woman named Alice Hamilton arrived at the Sangamon Street works, a lead-smelting plant on Chicago’s West Side, and asked to take a look around.

The owner welcomed her in. She was a small woman, unassuming. What harm could she bring to a powerful boss? She walked by the kettles and furnaces. She observed the sweating men holding shovels and prods. The air was stifling, full of humidity, and several times she covered her nose and mouth to dampen the scent of industrial chemicals wafting through the unventilated rooms. On the floor were pieces of scrap metal and a film of metallic dust, some of which also floated visibly in the air. A few men wore dirty uniforms, but most donned the same stained overalls they wore at home each night. There was a pile in one corner of large rubber respirators, but none of the men was using them. A few of them had tied dirty handkerchiefs around their mouths.

Hamilton walked around with a pen and pad in hand, listening. One man told her about a young immigrant from Bulgaria who’d been working here but had seemed to go crazy a few weeks earlier; the worker was removed from the plant in a straitjacket and later died. She heard of another man, also an immigrant, who was put to work making paste for batteries and had a habit of moistening his fingers on his tongue. He lasted ten days before he went home ill. One foreman told Hamilton that few of his men could work for more than a few weeks before they called in sick. Almost all had suffered the same symptoms, starting with hallucinations. The boss offered no payment for sick workers, and he didn’t appear to be making much effort to prevent them from getting sick. “Many times … I met men who employed foreign-born labor because it was cheap and submissive, and then washed their hands of all responsibility,” she wrote. “They deliberately chose such men because it meant … a surplus of eager, undemanding labor.”

In a time of booming production and thousands of new factories buzzing across America, Hamilton was arguably the first American physician to take a professional interest in the health and safety of workers—and one of the first to try to make American industries safer. She came to the “dangerous trades,” as she called them, in an indirect way. Born in 1869 into a wealthy family, Hamilton grew up on a sprawling estate that covered three city blocks in Fort Wayne, Indiana. Educated at Miss Porter’s, an elite boarding school in Farmington, Connecticut, she went to medical school in Michigan, graduating in 1893.

A doctor at 24, Hamilton could have taken her skills and privileged background in any direction. But something about her upbringing—the importance of “being helpful,” as her father, a businessman, had urged her to be—drove her to help the most marginalized people win political and social power.

A century later, Alice Hamilton’s work reaches deep into every aspect of modern life. She laid the foundation for occupational health and safety standards that protect millions of workers worldwide. She broke gender barriers in the broader sciences that opened stodgy male-dominated fields to women. And her approach to social justice—combining evidence-based research, interdisciplinary collaboration and community engagement—remains the blueprint for nearly all public health and policy fights today, from the smallest neighborhood disputes to global battles over pollution, natural resources and climate change.

But her battles were never easy, nor did vindication come quickly. And one battle stood high above the rest, because it would pit her against a deadly poison that would go on to sicken millions around the world.

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Lead, number 82 on the periodic table, was a miracle metal for thousands of years. The Roman Empire considered lead the everything element—the plastic of its era. It made pots last longer. It helped winemaking urns resist bacteria. And it made pigments in makeup brighter on people’s faces. Its resistance to corrosion, meanwhile, made it the perfect material for water pipes in homes, which Romans called “plumbing,” from the Latin word for lead, plumbum.

In medical school, Hamilton learned that lead was poisonous. The element had been known for millennia to bring out a person’s insanity, and historians had even debated whether Romans’ ubiquitous use of lead had hastened the collapse of their empire.

By 1900, America was the top miner of lead in the world. The country’s appetite was endless for its industrial and cosmetic uses, and even as a miracle health cure. Marketers spun lead as the key to a more prosperous life and promoted using it in cosmetics, medicines and children’s toys. But lead also had a dark side. The element had become so ubiquitous that, in 1910, the governor of Illinois asked Hamilton to investigate the conditions in factories that made lead and other chemicals, where men were getting sick and often dying in numbers too high to ignore. 

In 1921, an engineer at General Motors found another use for lead. He put a few drops into gasoline and found it reduced a phenomenon of incomplete fuel combustion known as “engine knock.” In the 1920s, a decade of robust American growth in every direction, this new substance—known as tetraethyl lead gasoline—quite literally fueled more powerful cars, more prosperous cities and a country on the rise.

But Hamilton saw a distinct threat. The first female professor at Harvard, she was acutely familiar with lead’s toxicity from her research among workers in Illinois, and she sought to convince the public that chronic low-level lead exposure from trace amounts in leaded gasoline was just as dangerous as lead poisoning, such as when a soldier suffered from a lead bullet wound. In 1922, the year after tetraethyl lead gasoline was invented, Hamilton became certain that it was a terrible idea, a historic blunder. She would spend much of the 1920s on an almost religious crusade against leaded gasoline. “This is a very dangerous form of lead,” she later wrote; based on her experience as a doctor and investigator, she believed tetraethyl lead would cause “insomnia, excitement, twitching muscles, hallucinations like those of delirium tremens, even maniacal attacks and convulsions, and death.” She wrote letters to the surgeon general and contributed to a series of Harvard studies into lead poisoning that showed that lead ingested in almost any quantity corrupted almost every organ. She wrote a nearly 600-page book about industrial poisons in the United States that devoted 14 of its 38 chapters to lead. She also leaned heavily on her friend Walter Lippmann, the famed progressive journalist for the powerful New York World newspaper, to launch a forceful campaign against tetraethyl lead and the lead industry. “Publicity is a wonderful thing,” she remarked. “It may be the pebble with which David will kill Goliath.”

Hamilton did not mince words, even when dealing with the most powerful men in high positions of America’s industrial companies. When the U.S. Public Health Service was debating the pros and cons of lead gasoline in May 1925, she walked right up to Charles Kettering, head of research for General Motors, and declared, “You’re nothing but a murderer.”

Kettering laughed off the insult. He was a powerful man with the backing of a friendly government. He had reason to think that Americans everywhere, happy in their powerful cars transforming American life, were rooting for him to succeed. 

Hamilton eventually lost the fight. Leaded gasoline went on to flood the country in the 1930s and ’40s. Once the U.S. government helped export it overseas, it was everywhere. Leaded gasoline simply became gasoline.

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Hamilton’s vindication would eventually come. She spent the next 40 years warning about the dangers of dozens of hazardous chemicals, including mercury, radium, asbestos and carbon monoxide. She wrote two more books, including her 1934 tome, Industrial Toxicology, which became an authoritative reference guide for workplace inspectors and industrial safety experts.

By the time Hamilton died in 1970 at the age of 101, she had done an enormous amount of work and seen a remarkable amount of change in her lifetime—from Reconstruction to men landing on the moon—but her legacy would be comparatively small. She was not prone to command attention, seek out fame or try to enlarge her profile. She did not make large endowments that would adorn buildings with her name or fund future students with scholarships. She never married and did not have children who might have promoted her legacy or safeguarded her records.

But in the 1970s, the burgeoning environmental movement and advancing medical research caught up to Hamilton, and the country began to see dynamic leaps of progress that would long outlive her.

Three months after Hamilton died in September 1970, a year marked by major expansions of environmental policy, President Richard Nixon signed the Occupational Safety and Health Act, a landmark law that at long last established a baseline for many of the healthy working conditions that Hamilton had spent a lifetime advocating for. A new government agency known as OSHA would set and enforce standards for job training and safety. And the law provided an avenue, for the first time, for workers to confidentially ask the government to inspect their workplaces for toxic and unsafe conditions. In the years that followed, a sprawling set of federal and state laws expanded protections for clean air and drinking water, combining human health into the broader ethos of environmentalism. Meanwhile, the U.S. began a mandated phase-down of leaded gasoline in 1975, and other countries followed, until Algeria became the last country to phase out the fuel in 2021, almost exactly a century since Hamilton first warned about its hazards. On Hamilton’s 100th birthday, Nixon wrote to Hamilton, then practically on her deathbed, to thank her for her century of work to improve people’s lives. 

Editors' note, March 13, 2025: This article has been updated to correct an error in the location of the Sangamon Street works.

Daniel Stone | READ MORE

Daniel Stone is a writer on science, history, and the environment. He's a former staff writer for National Geographic and a former White House correspondent for Newsweek. He lives in Santa Barbara with his wife and two sons, one of whom is a dog.