Did Leaded Gasoline Play a Role in Gary Ridgway and Richard Ramirez's Killings?

From the 1960s to the 1980s, lurid headlines of violent crime sprees were splashed across the front pages of newspapers nationwide. Serial killers like Jeffrey Dahmer, “Son of Sam” David Berkowitz, Ted Bundy, John Wayne Gacy, the Zodiac Killer and other murderers seemed to run loose throughout America.

These weren’t just trumped-up crime stories that sold newspapers; researchers have determined there was, in fact, a sharp increase in violent crimes during that era. Starting in the early 1960s, the rates of homicides, rapes, aggravated assaults and other violent crimes began to rise rapidly and peaked around 1990, then began to drop significantly, according to the FBI and other sources. 

This postwar crime wave has been attributed to many factors, including inflation and the loss of jobs in America’s Rust Belt. But some researchers believe that exposure to lead—especially from leaded gasoline—may have been a primary cause of the rise in violent crimes.

Lead is a heavy metal with a low melting point that’s also soft and malleable, making it ideal for shaping into everyday objects like coins, drinking vessels, jewelry, coffins and roofing tiles. It’s also been used as a wine sweetener, in cosmetics—think of the whitened faces of Japanese geishas and Queen Elizabeth I—and even as a contraceptive. 

But lead is also a potent neurotoxin that causes severe nervous system effects including brain damage and behavioral disorders. When car and truck ownership became a feature of middle-class life in the years after World War II, lead in the exhaust fumes from vehicles’ leaded gasoline soon showed up in Americans’ blood. 

In a study conducted from 1976 to 1980, the Centers for Disease Control and Prevention found that more than 77% of people in the United States had elevated blood lead levels. By 1994, after leaded paint was banned for most uses in the United States and leaded gasoline started being phased out, that percentage had dropped to just 4.4%. 

According to the Neurotoxicology and Teratology journal, “numerous studies link childhood lead exposure to a range of cognitive and behavioral deficits, including low IQ, impulsivity, juvenile delinquency, and criminal behavior in adolescence and early adulthood.”

That same study found that exposure to high levels of lead “early in life is statistically predictive of juvenile delinquency and arrests in young adults.” In other words, children who are exposed to high levels of lead are more likely to engage in criminal behavior in adulthood. 

Another study from PLOS Global Public Health, published in 2023, determined that “an excess risk for criminal behavior in adulthood exists when an individual is exposed to lead in utero or within childhood.” 

In her 2025 book Murderland: Crime and Bloodlust in the Time of Serial Killers, Pulitzer Prize-winning author Caroline Fraser explores the link between lead exposure and serial killings. Fraser grew up in the Pacific Northwest, where murderers such as Ted Bundy, Israel Keyes and Gary Ridgway were active in the 1970s and 1980s. 

“The fascinating thing about the correlation between leaded gas and violent crime is that you see a very sharp rise in violent crime in the 1970s,” Fraser told Inside Climate News. “It was over 10 per 100,000 people, and we’d never in the records of the FBI reached that before. That correlates with the post-World War II boom in people driving, which begins in the 1950s. People are buying more cars and commuting longer distances. There’s more leaded gas [fumes] entering the atmosphere.”

Ridgway—also known as the “Green River Killer”—offers what Fraser calls “a really interesting example of this kind of exposure.” Starting in 1982, Ridgway murdered at least 49 women in the Seattle area (though he later confessed to killing 71), then disposed of their bodies in the Green River wilderness area. He received 49 consecutive life sentences.

America’s deadliest convicted serial killer also grew up around toxic mine tailings and aircraft using leaded fuel. As an adult, Ridgway spent 32 years spray painting trucks at the Kenworth Trucking Co. plant in Renton, Wash., where he worked with leaded paint on an almost daily basis. “So he’s exposed to lead throughout his entire life,” Fraser notes.

Richard Ramirez, who terrorized Southern California in the 1980s as the “Night Stalker,” grew up in El Paso, Texas, downwind of a large lead smelting facility owned by ASARCO, the American Smelting and Refining Company. 

As a child, Ramirez displayed symptoms of developmental problems, including seizures and behavioral disorders that might have been the result of his childhood exposure to lead and other heavy metals. Fraser states Ramirez “developed a very, very violent fantasy life as a kid, which then he acted upon some years later as a young man in Los Angeles,” where he engaged in a bizarre series of seemingly unrelated crimes—including burglary, drug use, rape and murder—before his arrest in 1985. Ramirez was convicted of 13 murders and sentenced to death.

Despite evidence suggesting a link between lead exposure and criminal activity, some researchers argue that there are many other factors associated with people who commit violent crime, including poverty, childhood malnutrition, domestic violence, exposure to other pollutants and a lack of health care and access to education. (It would, of course, be ethically impossible to expose one group of children to high levels of lead to test their criminal tendencies decades later.)