Leaded

9 Dec 1921

Dayton. Car engines of the early 1920s knocked, and General Motors’ research men wanted a fuel that let them squeeze the mixture harder. By The Nation’s account, on 9 December 1921 a young engineer, Thomas Midgley Jr., told his boss, Charles Kettering, that tetraethyl lead stopped the knock. Kettering told federal officials in 1925 the team turned to lead “almost as a last resort,” and that it was “about forty or fifty times more effective than anything we had ever dealt with.” The Nation says GM’s own men had found alcohol blends among the best anti-knock fuels, and suggests the reason for lead was money; no document in our sources states GM’s reason.

Dec 1922

Before the first tank. Surgeon General Hugh Cumming told the 1925 conference his service had been “interested two years ago” when it learned a large corporation was trying lead compounds in gasoline. By The Nation’s account a Public Health Service laboratory director had warned in 1922 of a “serious menace to public health,” and in December 1922 Cumming asked whether there might be “a decided health hazard.” Midgley, about to leave work with lung trouble, answered that no experimental data had been taken. The service had no funds, so the first study of the fumes went to the Bureau of Mines, under an October 1923 agreement with General Motors’ research company, Ethyl’s research director wrote. By The Nation’s account Ethyl’s contract asked that the Bureau’s papers be submitted to the company “for comment, criticism, and approval.” Ethyl gasoline went on sale in Dayton on 1 February 1923.

1924

Ethyl. The Ethyl Gasoline Corporation came in 1924; its research director later called it the former General Motors Chemical Co. By The Nation’s account it was a joint venture of General Motors and Standard Oil of New Jersey, and du Pont made the tetraethyl lead. Frank Howard, speaking for Ethyl in 1925, said it “includes the General Motors Corporation and the Standard Oil Co. (N. J.)” and du Pont “in an indirect way.” Standard Oil of New Jersey was the old trust’s holding company, which the Supreme Court told in 1911 to give up its subsidiaries; in 1940 the Court recorded that it held half of Ethyl, with General Motors and du Pont owning the rest. By The Nation’s account the two sold Ethyl to Albemarle Paper in 1962. The old trust’s own story is told in The Trust.

26 Oct 1924

Deepwater and Bayway. The Public Health Service’s own list of fatal poisonings names du Pont’s plant at Deepwater, New Jersey, first; its general manager told the 1925 conference “We had fatalities,” the last in July 1924. At Standard Oil of New Jersey’s Bayway works Ethyl’s research director counted five dead in October 1924, and Al Jazeera’s background adds dozens hospitalised. Yale’s Yandell Henderson told the conference that, by different counts, 11 to 15 men had been killed and 50 to 100 poisoned. Ethyl’s director said the deaths had “nothing to do” with ethyl gasoline. By The Nation’s account a grand jury cleared Standard of criminal responsibility while finding the deaths due to poisoning, and du Pont’s 1936 history called Bayway’s precautions “grossly inadequate.”

Oct 1924

The demonstration. In autumn 1924, by The Nation’s account, Midgley rubbed the fluid on his hands for reporters. “I’m not taking any chance whatever,” he said, but added he would not do it every day. In 1925 he told federal officials tetraethyl lead was “not so much a dangerous poison as it is a treacherous one”: with discipline, “the record has become quite good.” New York State’s health commissioner told the same meeting that the city of New York had “prohibited the use of any form of ethyl lead.”

20 May 1925

Washington. On 20 May 1925 the Surgeon General called industry, doctors, labor and government together. Alice Hamilton of Harvard called lead “a slow and cumulative poison” whose signs are not easily recognised, and asked how a whole country could be controlled. Yale’s Henderson said the room held “two diametrically opposed conceptions,” and that lead “is not by any means the only substance” that can serve against knock. Howard called the additive “this apparent gift of God” for stretching the country’s petroleum.

20 May 1925

Ethyl’s answer. Ethyl’s case was that facts, not fears, should decide. Kehoe said that if an actual hazard were shown, leaded gasoline would be dropped “from that moment,” but it was “not a thing which may be thrown into the discard on the basis of opinions”; he did not regard his own data on men “as conclusive in any way.” Howard said the development “must be stopped, if it is stopped at all” by proof of the facts. Ethyl’s Webb said its board halted sales “without any pressure whatsoever”; a later Public Health Service report says it was “At the suggestion of the Surgeon General,” and the 1926 bulletin calls it voluntary but “a consequence of such apprehensions.” The conference asked for a committee of seven, “paid for exclusively out of public funds.”

17 Jan 1926

The committee. The committee studied 252 men: drivers, garage workers and, for comparison, workers exposed to lead dust. Drivers using ethyl gasoline showed “no definite signs of lead absorption” after about two years; garage workers showed somewhat more where it was used, “slight in comparison with” workers in lead industries. It wrote that “Longer experience may show” lead poisoning or chronic disease “of a less obvious character,” and asked for the study to go on. A 1959 Public Health Service report says state regulations were never adopted: Ethyl’s president “agreed voluntarily” to follow the recommended rules, which removed “the pressure for state regulations.” By The Nation’s account committee member David Edsall called the report “half-baked.”

1961

Cincinnati. Ethyl’s research director wrote that in June 1924 General Motors’ chemical company arranged with Robert Kehoe to spend part of his time on the medical side of tetraethyl lead. His Kettering Laboratory spent some thirty years on lead in ordinary people, and in 1960 he thanked the unnamed “industrial organizations that have financed these investigations.” The Nation names them as GM, du Pont and Ethyl, with a $130,000 gift, and says the lead industry paid his salary for half a century. Kehoe’s lectures put the level where lead poisoning begins “very little above or below 80 micrograms” per 100 grams of blood, and found “no great or immediate urgency” about lead in the air.

30 Mar 1959

1959. No law set the amount of lead in gasoline: the Public Health Service’s own report says “there are no state or federal laws pertaining to the hygienic aspects of TEL.” A committee met to judge raising the 3 cc a gallon the industry kept to; Ethyl and du Pont gave their figures, and Kehoe attended as Ethyl’s consultant. It found no data showing the rise would “significantly increase the hazard to public health from air pollution,” advised raising it by no more than 0.25 cc a year, and said a conclusive answer was impossible for lack of medical data. It added that some authorities thought the country was “close to the tolerable limits of lead absorption.”

Sep 1965

Pasadena. Clair Patterson came to Caltech to date the Earth, and Caltech’s archive says that by 1953 he had put it at 4.5 billion years. His samples kept coming out wrong; he said there was “lead in everything that I was using” that came from industry. His 1965 paper argued that the lead people carry is not mostly natural, and Caltech’s summary put existing body burdens at about 100 times the natural ones. Kehoe’s lectures held that a roughly comparable level of lead in the air “has existed for a long time.” Patterson said in 1995 that he had predicted the lead in people should be 100 times below today’s, and that later, accurate measurement made it 1,000: “I was off, the wrong way.” That is his account; The Nation calls Kehoe’s view “thoroughly discredited today.”

1965

Wham. Patterson said in 1995 that a consortium of oil companies had financed his lab, and that after a big paper saying the lead came from gasoline they stopped his research and tried to block his other grants. His department head, he said, “tried to protect me from the oil companies.” The Nation adds, quoting him, that Ethyl’s representatives tried to “buy me out through research support that would yield results favorable to their cause,” and that his Public Health Service contract was not renewed; it says “others have alleged” that Ethyl offered to endow a chair at Caltech if he was sent packing. That is Patterson’s account, and The Nation’s repeating of it. Asked in 2000, Ethyl’s spokesperson called The Nation’s whole piece “a distorted interpretation of known historic events and documents that have long been in the public record.”

28 Nov 1973

The rule. A National Academy of Sciences panel found in 1972, in words the court later quoted, that “about 98% of the airborne lead that can be traced to its source comes from combustion of gasoline.” EPA’s November 1973 rule cut lead in all grades. As the regulation stood in 1975 it stepped from 1.7 grams a gallon after 1 January 1975 down to 0.5 after 1 January 1979; EPA’s 1985 release says the plan had been 0.5 by 1980 and 1982, so the dates slipped. EPA said a significant part of the urban population, “particularly children,” was over-exposed, that leaded paint was “a primary source of exposure for poisoning in children,” and that it had also ordered unleaded gasoline to protect catalytic converters.

19 Mar 1976

Ethyl goes to court. Ethyl, du Pont and others argued the law required proof of actual harm. On 20 December 1974 a three-judge panel, one judge dissenting, set the regulations aside; the full court vacated that on 17 March 1975 and, on 19 March 1976, by five judges to four, upheld EPA. The dissent, by Judge Wilkey, found a “paucity of scientific evidence” and the rule “arbitrary and capricious.” By The Nation’s account the Supreme Court refused to hear an appeal. One strand of EPA’s own calculations used Kehoe’s experiments.

4 Mar 1985

Blood, and the last step. Between 1976 and 1980 average U.S. blood lead fell about 37 per cent, tracking falling gasoline lead; the authors called gasoline the most likely cause but wrote that “strong correlation does not prove cause and effect.” In March 1985 EPA cut the limit 90 percent, to 0.10 grams a gallon from 1986, estimating about $6 billion saved and almost one million fewer cases above 25 micrograms per deciliter by 1992. Its analysis also gave a preliminary estimate of over 5,000 deaths a year from blood-pressure-related disease among white men aged 40 to 59, which EPA said it would not yet rely on. The Clean Air Act banned leaded fuel for on-road vehicles from 1 January 1996.

2005

Children. Bruce Lanphear and colleagues pooled seven studies of 1,333 children and estimated, after a 2019 correction, a loss of 6.7 IQ points (interval 4.1 to 9.3) as blood lead rose from 2.4 to 30 micrograms per deciliter, and 3.8 (2.3 to 5.3) from 2.4 to 10. The correction fixed data errors; the authors write that EPA and other investigators concluded the errors “had only minor effects.” Set that beside Kehoe’s 80. These studies count lead from every source, not gasoline alone: EPA said leaded paint was a primary source of poisoning in children.

1979

The Needleman fight. In 1979 Herbert Needleman compared 58 children with high lead in their teeth to 100 with low levels; the high group scored lower, and none of 39 other variables explained the gap. NPR reports that scientists who represented the lead industry in lawsuits accused him of cherry-picking his data. Ernhart and Scarr wrote in 1993 that they had become whistleblowers; NPR does not name the accusers. The University of Pittsburgh found no scientific misconduct, though he “mischaracterized some procedures”; the federal Office of Research Integrity, the Globe reports, cleared him but cited a failure to get a representative population, with no finding that it changed his conclusions. EPA’s 1984 reanalysis, asked for in 1983, “confirmed the association.” A 1994 correction exists; we have not read it or the federal report.

2013

The crime story. A popular version says leaded gasoline explains most of the rise and fall of U.S. violent crime. Mother Jones credited the 90 percent to Rick Nevin’s 2000 paper, which found gasoline lead “remarkably consistent with” later changes in violent crime, and itself warned that “a single correlation between two curves isn’t all that impressive.” Jessica Wolpaw Reyes’s 2007 study of state-by-state falls estimated an elasticity of about 0.8: a 10 percent fall in lead, about an 8 percent fall in violent crime.

2022

What the studies add up to. The 90 percent is a fit between two curves, not a pooled estimate; the only pooled estimate of a share is the 2022 meta-analysis, at 7 to 28 percent of the fall in homicide. It found an elasticity of 0.09 against Reyes’s 0.8, said the effect is “overstated in the literature due to publication bias,” and found the mean partial correlation only 0.01 in studies using natural experiments. Individual studies differ: a Cincinnati study of 250 people, drawn from areas of old, lead-contaminated housing, found arrest-rate ratios from 1.07 to 1.48 per 5 micrograms per deciliter, with two of six intervals including 1. The meta-analysis did not pool it.

30 Aug 2021

Algeria. On 30 August 2021 the U.N. Environment Programme said Algeria, the last country to use leaded petrol, had used up its supplies the month before; the United States, China and India had stopped earlier. UNEP projected that ending it would prevent more than 1.2 million premature deaths a year and save $2.44 trillion, a dollar figure from a 2010 study that counted lower medical costs and “a dip in criminal activity.” Those are projections, not counts. EPA’s 1996 notice shows leaded fuel was still allowed in the U.S. for aircraft and other off-road uses.