The Leaded Century

In 1921, Thomas Midgley Jr., a chemist at General Motors working under engineer Charles Kettering, was tasked with solving engine knock -- the pinging sound caused by premature ignition of fuel in high-compression engines. Knock limited engine power and efficiency. GM needed a fix.

Midgley found two candidates. One was ethanol -- grain alcohol. It worked, it was inexpensive, it could be produced anywhere in the world, and it had no patent potential. Any farmer could make it. The other was tetraethyl lead, a highly toxic organolead compound. TEL worked as an antiknock additive. And crucially, it was something GM, Standard Oil, and DuPont could manufacture, control, and patent.

In 1923, General Motors and Standard Oil of New Jersey -- the successor to Rockefeller's Standard Oil trust -- formed the Ethyl Corporation to manufacture and market TEL. DuPont, which had the chemical manufacturing expertise neither company possessed, operated the plants. Three of America's most powerful corporations had united behind a product that would poison the country's air for the next seventy years. Ethyl Corporation. The Nation.

Midgley himself contracted lead poisoning during his development work and took a five-month leave of absence to recover. He knew what he had made. He promoted it anyway. J.R. McNeill, the environmental historian, later described Midgley as having done "more impact on the atmosphere than any other single organism in Earth's history" -- he also invented Freon, the chlorofluorocarbon that destroyed the ozone layer. CNN.

At DuPont's tetraethyl lead plant in Deepwater, New Jersey, workers began exhibiting symptoms of acute lead poisoning within the first year of operation. Hallucinations. Paranoid delusions. Mania. Workers would stop mid-sentence and grab at invisible insects they believed were flying around them. They named the plant "the House of Butterflies." In the first two years of operation, at least eight DuPont workers died and more than 300 were poisoned. Pitt Med.

In September 1924, Standard Oil of New Jersey opened a TEL production unit at its Bayway refinery in Elizabeth, New Jersey. By October, five workers had died and 44 had been hospitalized. One died in a straightjacket. The Union County medical examiner opened an investigation. Within hours, the story was front-page news across the country. Newspapers called it "loony gas." WolfeNotes.

Charles Kettering and other GM executives told the press that workers had died because they hadn't followed safety procedures. This was the company's standard response to every death that followed: the workers were careless. The product was safe. The public panic was overblown. General Motors had invested its future in tetraethyl lead. It was not going to acknowledge that the substance was killing the people making it.

In May 1925, Surgeon General Hugh Cumming convened a conference to determine whether leaded gasoline should be permitted. The panel included industry representatives from GM, Standard Oil, and the Ethyl Corporation. Two outside voices were allowed in: Dr. Alice Hamilton of Harvard, the country's leading authority on industrial medicine, and Dr. Yandell Henderson of Yale, a physiologist.

Henderson's testimony was prescient:

"Conditions would grow worse so gradually and the development of lead poisoning will come on so insidiously ... that leaded gasoline will be in nearly universal use and large numbers of cars will have been sold ... before the public and the government awaken to the situation." US EPA.

The committee's conclusion: the evidence was insufficient to prohibit leaded gasoline, and more research was needed. Production resumed. No ban. No regulation. The industry was left to police itself.

The man who would do the policing for the next four decades was Robert Kehoe, a physician at the University of Cincinnati. The Ethyl Corporation, GM, Standard Oil, and DuPont funded the Kettering Laboratory at UC, where Kehoe served as director. Kehoe then spent forty years arguing that lead was naturally present in the human body -- it is not -- and that there was a safe threshold below which it caused no harm -- there is not.

Kehoe's 'show me the data' paradigm demanded empirical proof of harm before any restriction, while ensuring that the data being produced was funded and controlled by the industry being studied. The Kettering Lab model became the template for the tobacco industry's scientific defense of cigarettes in the 1950s and 1960s -- and later, for the fossil fuel industry's climate denial operations. The playbook was written in Deepwater, New Jersey, in 1925. Wikipedia AJPH 2022.

In the 1950s, Clair Patterson was a Caltech geochemist trying to determine the age of the Earth by measuring lead isotopes in ancient rocks. To do this accurately, he had to build one of the first contamination-free clean rooms in scientific history, because lead was everywhere -- on laboratory surfaces, in the air, in the water, in his own hands. That ubiquity was the finding.

In 1965, Patterson published a landmark paper showing that lead concentrations in the environment -- in seawater, in polar ice cores, in human blood -- were approximately 625 times higher than pre-industrial natural levels. Almost all of it came from automobile exhaust. The lead industry was poisoning the atmosphere, and everyone breathing it was being continuously poisoned as well. Caltech.

The response from the lead industry was immediate. The American Petroleum Institute terminated its research funding. Patterson's Public Health Service contract was canceled. Industry representatives pressured the National Research Council to exclude him from advisory panels on air pollution. His collaborators were pressured. His funding sources were approached. For over a decade, the organized scientific apparatus of the Ethyl Corporation and its allies worked to discredit, defund, and isolate the man who had proved they were poisoning the country.

Patterson was not silenced. He testified before Congress. He published continuously. He documented the industry's campaign against him. His work was central to the EPA's 1972 decision to begin phasing down tetraethyl lead. Caltech Magazine.

In March 2022, researchers at Florida State University and Duke University published a study in the Proceedings of the National Academy of Sciences. The title: "Half of US Population Exposed to Adverse Lead Levels in Early Childhood." The paper won the Cozarelli Prize from the National Academy of Sciences.

Key findings: more than 170 million Americans -- over 53% of the population alive as of 2015 -- had blood lead levels above 5 micrograms per deciliter as children, the level the CDC now defines as elevated. The primary source was automotive exhaust from leaded gasoline. The estimated total cognitive damage: 824 million IQ points lost -- roughly 2.6 IQ points per person on average, with higher impacts concentrated in communities near highways and in low-income neighborhoods. PNAS 2022 Duke.

A separate body of research connects the leaded gasoline era to the violent crime wave of the 1970s through 1990s. Economist Rick Nevin's 2000 analysis found that gasoline lead consumption explains 90% of the variation in US violent crime rates when a 23-year lag is applied -- the approximate time between childhood lead exposure and peak criminogenic years. His findings replicated across nine countries.

In 2007, economist Jessica Wolpaw Reyes of Amherst College used the fact that different US states phased out leaded gasoline at different rates -- a natural experiment -- to isolate the effect of lead reduction. Her finding: between 1992 and 2002, the phase-out of leaded gasoline was responsible for approximately "56% of the decline in violent crime." The cities and states that phased out lead earlier saw crime fall earlier. The cities and states that kept it longer saw crime persist longer. Lead-Crime Hypothesis.

The generation that grew up breathing leaded exhaust in the 1950s through 1980s also became the generation mass-incarcerated in the 1990s and 2000s. Lead poisoning damages the prefrontal cortex -- the part of the brain responsible for impulse control, planning, and emotional regulation. The industry that lobbied to keep lead in gasoline for fifty years was, by the research, one of the largest contributors to the conditions that produced the carceral state.

The EPA began regulating lead in gasoline in 1972 -- three years after the National Environmental Policy Act, fifty years after Midgley invented tetraethyl lead, and forty-seven years after Alice Hamilton told the Surgeon General's conference that poisoning the country's air was a catastrophic mistake.

The phase-down was slow. Leaded gasoline for US passenger vehicles was banned in 1986. The final US use ended in 1996. Leaded aviation gasoline (avgas) in the US continued until 2024. The last country in the world to phase out leaded gasoline for road use was Algeria, in 2021 -- ninety-eight years after the Ethyl Corporation was founded.

The perpetrators and their successors:

General Motors -- operating today, $180B+ annual revenue, never charged.

Standard Oil of New Jersey → ExxonMobil -- operating today, one of the world's largest oil companies by revenue, never charged.

DuPont → Corteva + Chemours -- operating today; the TEL chemical operations were eventually divested, never charged.

No executive at any of these companies was ever indicted, prosecuted, or convicted for the manufacture and marketing of a substance they knew from the first year of production was killing workers. No one was charged for the decades-long campaign to suppress the science. No one was charged for lobbying to keep a neurotoxin in the air supply for fifty years after it was proven dangerous.

The 170 million Americans who grew up with elevated lead levels in their blood have no legal claim against the companies that put it there. The statute of limitations has long since expired. The harm is permanent. The companies are profitable.