When Ted Bundy was a child in the 1950s, he hunted for frogs in the nearby swamps in Tacoma, Washington. The young Gary Ridgway, the future Green River Killer, grew up just a short drive north. Both men went on to become prolific serial killers, raping and mutilating dozens of women, starting in the 1970s and ’80s. These types of sociopaths are exceedingly rare, representing less than a tenth of 1 percent of all murderers by some accounts. Yet in Tacoma, they were surprisingly common — and there were more than just Bundy and Ridgway.

In her new book Murderland: Crime and Bloodlust in the Time of Serial Killers, the Pulitzer Prize-winning author Caroline Fraser maps the rise of serial killers in the Pacific Northwest to the proliferation of pollution. In this case, the lead- and arsenic-poisoned plume that flowed from Asarco’s metal smelter northwest of Tacoma, which operated for almost a century and polluted more than 1,000 square miles of the Puget Sound area, the source of the famous “aroma of Tacoma.”

Fraser grew up in the 1970s on Mercer Island, connected to Seattle by a floating bridge with a deadly design, not far from a terrifying lineup of serial killers. George Waterfield Russell Jr., who went on to murder three women, lived just down the street, a few years ahead of Fraser at Mercer Island High School. (No surprise, his family once lived in Tacoma.) She had always thought the idea that the Pacific Northwest was a breeding ground for serial killers was “some kind of urban legend,” she told Grist. 

But after much time spent staring at pollution maps, and looking up the former addresses of serial killers, she came up with an irresistible hypothesis: What if lead exposure was warping the minds of the country’s most harrowing murderers? In Murderland, Fraser makes a convincing case that these killers were exposed to heavy metal pollution in their youth, often from nearby smelters and the leaded gasoline that was once burned on every road in the country.

Studies have shown that childhood lead exposure is connected to rising crime rates, aggression, and psychopathy. In children, it can lead to behavior that’s been described as cruel, impulsive, and “crazy-like”; by adulthood, it’s been linked to a loss of brain volume, particularly for men. Fraser doesn’t pin sociopathy solely on exposure to lead, though she suggests that it’s a key ingredient. 

“Recipes for making a serial killer may vary, including such ingredients as poverty, crude forceps deliveries, poor diet, physical and sexual abuse, brain damage, and neglect,” Fraser writes. “Many horrors play a role in warping these tortured souls, but what happens if we add a light dusting from the periodic table on top of all that trauma?”

Fraser is a fan of true crime, but when writing the book, she tried to correct for what she sees as the genre’s problems, she said. Biographers often zoom in on a killer in isolation, like Ted Bundy or the Zodiac killer, and he comes off as some kind of mastermind. In Fraser’s telling, with all their deprived murders placed side-by-side, these killers seem patterned, almost predictable. “It was also revealing to see that they’re not only not as smart as we may have thought they were after Hollywood got through with them, but that their behavior is so similar,” she said. “Like, they’re almost kind of automatons, where their behavior’s very robotlike.” 

Fraser draws a parallel between murderers as we normally understand them and more indirect killers, the book’s true arch-villain: smelting companies and the people profiting off them, like the famous Guggenheim family that acquired Asarco. In 1974, officials at Asarco’s Bunker Hill smelter in Kellogg, Idaho, did a back-of-the-napkin estimate and found that poisoning 500 children with lead had a legal liability of merely $6-7 million, compared to the $10-11 million they’d make by increasing lead production. So the choice was easy. 

“The behavior of the people who built these smelters, invested in them, ran them, continued to emit tons of lead and arsenic into the air in populated cities — I mean, it’s beyond astonishing, what they did,” she said. Take Dr. Sherman Pinto, the medical director at the Tacoma smelter, who claimed that the lung cancer deaths among workers were simply because of pneumonia. “It just struck me how much their behavior is comparable to that of serial killers, because they’re constantly lying,” Fraser said.

Beyond the Pacific Northwest, the book follows the depraved behavior of Dennis Rader in Kansas in the 1970s and 1980s, and Richard Ramirez in California in the 1980s — both of whom also grew up near smelting. Even London’s famous Jack the Ripper was probably poisoned by the lead smelting boom in the 19th century, driven by demand for paint. Yet Murderland focuses on Washington state for a reason. When Fraser looked at the Washington Department of Ecology’s map of lead and arsenic contamination, she saw four plumes: The fallout from Asarco’s Tacoma smelter, another smelter plume in Everett, former orchard lands in central Washington that were sprayed with lead arsenate as a pesticide, and a cleanup site on the upper Columbia River. 

“Every one of those plumes, including the most remote and least populated site on the Columbia, has hosted the activities of one or more serial rapists or murderers,” Fraser notes. (Israel Keyes, the serial killer and necrophiliac, grew up downriver from the Trail smelter in British Columbia.)

Leaded gas was fully phased out in the United States by 1996, and metal smelters have largely been decommissioned for financial reasons. But the legacy of lead remains with us. A recent experiment found that about 90 percent of toothpastes tested contained lead; a few weeks ago, the supermarket chain Publix recalled baby food pouches after product testing detected lead contamination. Last year, the Biden administration issued a regulation requiring drinking water systems across the country to replace lead pipes within 10 years, but the Trump administration and some Republicans in Congress are trying to roll back these protections.

“Regardless of whether you agree with my connection between lead exposure and serial killers, I do think people really need to be aware that that was a huge part of our history, and it’s still out there,” Fraser said. “I hope that this book does something to help people make connections between where they live, and what they might be exposed to, and what that might mean.”