This post is part of an exchange between “Books, Health, and History” at the New York Academy of Medicine and The Public’s Health, a blog of the Philadelphia Inquirer.

By Christian Warren, Associate Professor of History, Brooklyn College

Estimates of environmental lead’s harms today would be far, far worse had it not been for Clair Patterson’s groundbreaking research. U.S. CENTERS FOR DISEASE CONTROL AND PREVENTION

The world is a lot less polluted with lead than it was a half-century ago, thanks in part to geochemist Clair Patterson. Fed up with lead contamination in his laboratory, he mounted a research campaign that overturned decades of misguided industry-sponsored science. In 1965 he published a game-changing article declaring: “the average resident of the United States is being subjected to severe chronic lead insult.” Patterson wanted to shock a nation in denial about the cost of its embrace of all things lead. Some saw his argument as darkly prophetic. Others saw it as patently absurd.

Lead’s proponents had 40 years of scientific studies to lean on—science bought and paid for by the very companies covering the earth with lead. In 1923 Standard Oil and General Motors had introduced leaded gasoline—a disastrous debut involving front page horror stories of workers driven to madness or agonizing death from lead exposure. But the lead industries minimized the fallout brilliantly. First, they finessed a federal investigation into the dangers; second, they founded a lead-friendly research institution at the University of Cincinnati. Under the direction of Robert Kehoe, the Kettering Laboratory quickly became the world’s authority on lead and health.

By the early 1960s, when the tobacco industry and others were ginning up the manufacture of doubt about their toxic products, Kehoe had a long career amassing a huge store of what passed for scientific certainty. Dozens of his studies “proved” that lead posed no public health threat. Lead, he explained, was a natural component of the environment, and humans had evolved in a leaded environment. And, Kehoe maintained, a little lead was harmless. It might pose a danger above a certain threshold, but below that level there was no need to worry. Our modern urban environment with lead spewing out of every automotive tailpipe in the country, did not, he concluded, push us above that threshold. Bottom line: the public faced no risk from lead exposure. Patterson’s 1965 research article, “Contaminated and Natural Lead Environments of Man” did not blast a mighty hole in the lead industry’s fortress of certitude but it struck a sharp blow with pinpoint accuracy. The small fissure it opened ultimately undermined the lead industry’s foundation. Initially the industry responded with dismissals and character assassination—the same playbook followed by other polluters under attack. Patterson would not surrender and kept the hard science coming. (He died in 1995 at age 73.)

Patterson’s battles with lead contamination began in the laboratory. Studying the composition of meteorites early in his career he was frustrated by laboratory lead contamination, leading him to develop new clean-room protocols. The payoff came in 1956, when Patterson calculated the age of the earth to be 4.5 billion years, a figure accepted by scientists to this day.

To understand the sources of environmental lead pollution Patterson went to sea to measure the extent of lead in the ocean’s depths. He voyaged to frigid mountaintops and then to the earth’s coldest regions following the lead trail. He proved that lead pollution had been rising since antiquity—and that it had spiked since the introduction of leaded gasoline in the middle of the 20th century. These findings drove Patterson into the thick of environmental politics, perhaps the most treacherous environment he ever braved.

Patterson’s article used the new standards of proof in medicine and public health that looked at large populations instead of individuals, finding relationships between behaviors and health outcomes. The Surgeon General’s first report on cigarette smoking, published one year earlier, used this approach.

Through a brilliant application of the kind of atomic bean counting that he’d employed in establishing the earth’s age, Patterson demonstrated that the average American’s body contained a hundred times more lead than was natural. In later publications he drove this point home with a powerful graphic: the outlines of three human torsos, each with dots representing the amount of lead in their bodies. The figure for primitive man had one dot; the second and third figures, representing the average modern American and a patient at Kehoe’s “threshold” for clinical lead poisoning, were both grey with dots, barely a shade apart. The stakes, Patterson insisted, went beyond the health of individuals. “[T]he course of history,” he asserted, “may have been and is now being altered by the effect of lead contamination upon the human mind.”

Thanks to Patterson’s scientific work and the regulations it ultimately inspired we all live in a much less heavily leaded world than the one Patterson explored. But we still have far to go. Most new uses of lead-containing products have been banned in America for a generation, but the lead left behind from centuries of relying on “the useful metal” still poisons our homes and lands. The tremendous progress since Patterson’s day revealed lingering, pervasive harms caused by the lead that remained—learning and behavior deficits as well as cardiovascular and immunological consequences. And in many parts of the world, lead pollution remains far worse than in the U.S., with even greater impact on public health. Concerned citizens must demand the regulations and clean up efforts that will eliminate every last “dot” of lead from every man, woman, and child on the earth.

Christian Warren, author of Brush With Death: A Social History of Lead Poisoning, is associate professor of history at Brooklyn College of the City University of New York, where he studies the history of health and the environment.