Leaded petrol: one man's fight against an industry's science

Series: How minds are moved · The official line vs what people lived · 2 of 7

In October 1924, at Standard Oil’s Bayway works in New Jersey, five men died and dozens more were taken to hospital after working with a new petrol additive, tetraethyl lead. Some had hallucinated before they died. At a DuPont plant nearby, the workers had already named the building where the stuff was made “the house of butterflies”, because the men inside began to see insects that were not there. A company spokesman told reporters the men “probably went insane because they worked too hard”. It took until 1996 for the United States to ban leaded petrol for cars, and until July 2021 for the last country in the world, Algeria, to stop selling it.

This post is about how an industry kept a known poison in the air for most of a century, and about the scientist who would not let it go.

Contents · 9 sections

TL;DR #

• Lead was a known poison long before 1921, when a General Motors team found that tetraethyl lead stopped engines knocking. It was sold under the friendlier name “Ethyl”.
• After workers died, the industry used three moves: a public show of safety, a government study paid for and approved by the industry, and a rule that critics must prove harm instead of the seller proving safety.
• For about forty years, the “safe level” of lead in Americans was set largely by one industry-funded laboratory, under Robert Kehoe.
• A geochemist, Clair Patterson, measuring the age of the Earth, found lead everywhere and spent the rest of his life fighting to remove it. He lost contracts and was left off an expert panel.
• When the lead went out of petrol, the lead in Americans’ blood fell by about 80%.

What it is #

In the book I am writing, SHTF vs STFU, there is a chapter I called “A Gift of God”, after a sentence spoken in Washington on 20 May 1925. Frank Howard of the Ethyl Gasoline Corporation told a one-day conference called by the US Surgeon General that leaded petrol was “a gift of God”, and asked whether it should be given up “merely because of our fears”.

In that same room, Yandell Henderson, a physiologist from Yale, predicted that lead poisoning from car exhausts would come on so slowly that leaded petrol would be in nearly universal use “before the public and the government awaken to the situation”. It is one of the most accurate predictions I have found in all my research for the book.

This is a story of reassurance more than of lies. The official line was not “lead is safe”. It was “the danger is only in the factory, and only if you are careless”.

How it works #

Name the product something softer. In 1924 General Motors and Standard Oil of New Jersey formed a joint company to sell the additive, with DuPont making it. They called it Ethyl. As Bill Bryson notes in A Short History of Nearly Everything, which is in my library, “ethyl” sounded friendlier than “lead”. A name is the first piece of persuasion.

Perform safety in public. After the deaths, Thomas Midgley, the chemist who had found the additive, held a press conference. He poured tetraethyl lead over his hands and held a bottle of it under his nose for about a minute, saying he could do this every day without harm. He had been seriously poisoned by it himself months earlier, and had gone to Florida to recover.

Buy the science, and the vocabulary. The US Public Health Service asked the Bureau of Mines to study whether leaded petrol was safe. General Motors paid for the study and was allowed to see and approve the results before publication. Sheldon Rampton and John Stauber’s Trust Us, We’re Experts, also on my shelf and drawing on the historians Gerald Markowitz and David Rosner, records that the Bureau avoided the word “lead” in its own letters, because the word was “apt to prejudice somewhat against its use”. The study exposed animals to exhaust for a few months, found none died, and was presented as proof of safety. Several states that had banned “ethyl gasoline” lifted their bans.

Reverse the burden of proof. This was the decisive move. After 1925, the industry did not have to show that lead in city air was safe. The critics had to show, with hard data, that it was harmful. And most of the data came from one place.

The industry’s scientist and the man who measured the Earth #

That place was the Kettering Laboratory at the University of Cincinnati, funded by General Motors, Ethyl and DuPont, and named after Charles Kettering, whose team had invented the additive. Its director, Robert Kehoe, was also the medical director of the Ethyl corporation. His position, held for some forty years: lead occurs “naturally” in the body, the body gets rid of small amounts, and only large, sudden exposures are dangerous. To any critic, his answer was: show me the data.

The man who brought the data was not looking for lead in people at all. Clair Patterson, an Iowa farm boy turned geochemist, was trying to date ancient rocks. His samples kept being contaminated by lead from the air of the laboratory. To get clean measurements he invented clean-room methods, and in 1953 he worked out the age of the Earth: about 4.55 billion years, still the accepted figure.

Then he went looking for the world before leaded petrol. In layered Greenland ice he showed that atmospheric lead had been tiny before the 1920s and had climbed steeply since. In 1965 he published a paper, “Contaminated and Natural Lead Environments of Man”, arguing that typical lead levels in Americans were far above natural ones. His key point was about a word: “normal” should be replaced with “typical”. Just because everyone had it did not mean it was harmless.

At US Senate hearings in 1966, Kehoe and Patterson both testified. Kehoe held that the levels found in people were natural.

What followed for Patterson, as Bryson describes it, was “a hellish campaign”. The American Petroleum Institute cancelled a research contract with him, and so did the Public Health Service. In 1971 he was left off a National Research Council panel on atmospheric lead, although he was by then, in Bryson’s words, “unquestionably the leading expert” on it. The journalist Jamie Lincoln Kitman later reported that industry figures pressed his university to get rid of him. That is a second-hand allegation. What is documented is that Caltech kept him.

What it felt like from the inside #

For most people, nothing. That is the point of a slow poison sold with a reassuring story. There was no day when the air smelled of lead. The petrol pump said “Ethyl”, the cars went faster, and the experts said the dose was natural.

The people who felt it first were the workers. The doctor Alice Hamilton described in 1925, in the Journal of the American Medical Association, men who became violent, restless and delusional. A medical student named Herbert Needleman, who took a summer job at the DuPont plant in the 1950s, later remembered a group of older men who moved slowly and stared into space at break time: the survivors of the house of butterflies. In 1979, as a paediatrician, he published a study of about 2,500 children’s milk teeth showing that more lead went with lower test scores. In 1991 two psychologists, Claire Ernhart and Sandra Scarr, who had both appeared on the industry side in a lead lawsuit, accused him of scientific misconduct. After a university hearing and a federal review, he was cleared in 1993.

What it can and cannot do #

The doubt worked for a long time, but not forever. The US began cutting lead in petrol in the 1970s, partly because new catalytic converters could not work with it. The European Union banned it in 2000. On 30 August 2021 the UN Environment Programme announced that the era of leaded petrol for cars was “officially over”. Lead is still used in some aviation fuel.

Some researchers go further and link the rise and fall of violent crime to the rise and fall of lead in the air twenty years earlier. That is the “lead-crime hypothesis”. It is contested: some studies find a strong link, others a weak one or none. I mention it as an open question, not a fact.

To be fair to the industry’s side as it was then: in 1925, nobody had measured low-level lead effects in children, and the cars really did need a fix for knocking. Alternatives existed (ethanol was one), but they were not without cost. The failure was not that people in 1925 did not know everything. It was that the people who profited were allowed to decide what counted as evidence, for forty years.

How to notice it #

• A soft name for a hard substance. Ask what the product actually is, not what it is called.
• Safety theatre. A dramatic public demonstration is not a study.
• Who funded and who approved? If the seller can see and approve a safety report before publication, it is not independent.
• “Natural” and “normal”. Ask whether “normal” means “harmless” or only “common”.
• The burden test. Is the seller asked to prove safety, or are the critics asked to prove harm?
• What happens to the critics. Lost contracts, missing panel seats and misconduct complaints against the person with the data are signs worth noting.

Frequently asked questions #

Did the companies know lead was poisonous? #

Yes. Lead poisoning had been known for centuries, and workers died in their own plants in 1924. What was argued about was whether the small amounts spread by car exhaust were harmful to the public.

Was Robert Kehoe dishonest? #

The record shows he was funded by the industry and that his view of “natural” lead has been disproved. Whether he believed it is a different question; he may well have. The structural problem was that the main source of data and the main source of money were the same.

Why did it take until 2021 to end leaded petrol worldwide? #

Poorer countries kept older cars and refineries, and the switch had costs. The UN Environment Programme ran a long campaign; Algeria used up the last stocks in July 2021.

Is the lead-crime link proven? #

No. It is a serious hypothesis with mixed evidence. Treat it as a question.

The lesson #

The industry did not need everyone to believe lead was safe. It needed the question of who must prove what to be settled in its favour, early, and quietly. Once that rule was in place, a single funded laboratory could hold the line for forty years, and the scientist who brought clean measurements had to fight for his funding. When you next hear “there is no evidence of harm”, it is worth asking the 1925 question back: has anyone been allowed to look?