The history of the ecological shadow of leaded gasoline begins on a Friday late in 1921. For five long years, Thomas Midgley Jr. and his team in the Fuel Division of the General Motors Research Corporation had been searching for an effective additive to increase the octane of gasoline, and thus reduce engine “knock” or pinging. Their successful test of tetraethyl lead at the DuPont plant on Friday, 9 December 1921, set DuPont and GM in motion. The new additive was effective, it was inexpensive, and a patent was easy to obtain.
Then, in October 1924, just as consumers all across the United States were beginning to switch to the “improved” gasoline, tragedy struck at several lead-processing plants. Before long, medical specialists and government regulators were questioning the safety of putting a known poison into gasoline (and thus also into automobile exhaust). The history of leaded gasoline could have ended—but did not—with this seemingly commonsense questioning. Instead, after a brief pause for “research,” no one would again seriously question the safety of leaded gasoline until the 1960s, when geochemist Clair Patterson began to wonder why his tests were indicating such high lead levels in the northern hemisphere.
Why did U.S. regulators declare leaded gasoline “safe” in the 1920s? Why were critics, once so loudly calling for precaution and further research, so quiet in the following decades? And, finally, why were so many scientists, activists, and government agencies in the United States suddenly—a half century later—beginning to challenge the “facts” and “safety” of leaded gasoline?
The answers reveal important lessons about how and why ecological shadows form, intensify, and shift. They reveal how the pursuit of profits and markets can trump calls for precaution even in the face of high uncertainty and significant risks, how corporations and state allies can silence critics and control “research” for generations, and, finally, how knowledge and technology can both cause and begin to mitigate ecological shadows.
Knocking occurs when part of the fuel in a cylinder ignites prematurely. This makes a pinging sound, causes the engine to run rough, and eventually damages it. It was common in internal combustion engines before the 1920s, worsening with higher compression ratios and increased engine power. Midgley’s team ran thousands of tests before discovering the value of tetraethyl lead as a fuel additive.1 At first, the team was willing to test just about any compound—even melted butter. A few were near successes. Back in December 1916, Midgley found that iodine could eliminate knock, but, besides being highly corrosive to engine parts, it was expensive, adding a dollar to the cost of a gallon of gas. Two years later, Midgley and his team were encouraged to discover that aniline was even more effective than iodine, although still unsuitable.
The need for an effective antiknock agent was even greater after World War I, when the world turned to lower-quality oil reserves. By then, some geologists were estimating that reserves in the United States would run dry in a generation or two, and U.S. automakers were becoming increasingly eager to develop more efficient fuels.2 Midgley and project head Charles F. Kettering did consider other options besides finding a low-cost and low-percentage antiknock additive for gasoline. One possibility was to replace gasoline with industrial (ethyl) alcohol from crops like corn and sugarcane. Another was to mix industrial alcohol and gasoline to create an antiknock fuel.
The team eventually dismissed both options on economic grounds. The main reason was straightforward: it was impossible to patent industrial alcohol. At the time, farmers could make it in a backyard still. Thus the potential for future corporate profits was far greater with a patented antiknock additive for gasoline. There were other reasons as well. The oil firms were opposing any shift away from gasoline. And there were practical barriers to a switch to industrial alcohol. “The present total production of industrial alcohol amounts to less than four percent of fuel demands,” Kettering would later explain in a 1921 speech, “and were it to take the place of gasoline, over half of the total farm area of the United States would be needed to grow the vegetable matter from which to produce this alcohol.”3
The search for a cheap and effective antiknock additive for gasoline was therefore continuing with ever greater intensity by the early 1920s. In the spring of 1921, Midgley’s team found yet another chemical—the solvent selenium oxychloride—able to prevent knocking. Unfortunately, “it had some disadvantages,” Midgley would wryly explain afterward, “not the least of which was its tendency to turn the engine into a chemical solution.” Midgley’s team doggedly went on testing more compounds. Soon they found that diethyl telluride was even more effective at eliminating engine knock, but it stank horridly, having, in Midgley’s typically playful words, “a satanified garlic odor” that “would cling to you for weeks.”4
These near successes helped Midgley narrow his search. Using the periodic table, he worked his way toward the heavy end of the carbon group, eventually reaching lead. This he tested in a compound called “tetraethyl lead,” first discovered by a German chemist in 1854 but never used commercially because of its toxicity. The breakthrough came in the DuPont plant in a simple experiment in December 1921, when Midgley’s team started up a one-cylinder Delco-Light engine filled with kerosene containing 0.025 percent tetraethyl lead. The engine ran smoothly—even better than with the adopted standard of 1.3 percent of aniline. Soon it became clear that a “spoonful” of tetraethyl lead, costing only a penny, “was enough to convert a gallon of gasoline from a rattling, knocking nuisance into a smooth-running motor fuel.”5
The team quickly filed a patent for the blend of gasoline and tetraethyl lead, then turned to refining, manufacturing, and marketing the new fuel. They added ethylene dibromide to minimize the buildup of lead deposits in the engine (which damages spark plugs and valves). In October 1922, GM contracted DuPont to supply tetraethyl lead: Pierre du Pont signed as president of GM, while his younger brother, Irénée, signed as head of DuPont.6
Two months later, the U.S. Surgeon General wrote the chairman of the board of DuPont to ask whether the company was sure that tetraethyl lead was safe. This “had been given very serious consideration,” Midgley wrote back on the chairman’s behalf. He admitted that he did not have “actual experimental data.” Still, “the average street,” he wrote confidently, “will probably be so free from lead that it will be impossible to detect it or its absorption.”7
The new fuel blend went on sale in February 1923 without any research on the potential health effects. Lagging well behind Ford, whose Model T sales were in full surge, General Motors was eager to introduce a gasoline that could eliminate engine knock: marketing its more powerful cars—such as GM’s flagship Cadillac—was central to its comeback strategy. GM advertised its “ethyl gas” as “a better fuel for motors.”8
The General Motors Chemical Company was formed in the spring of 1923 to market ethyl gas: Kettering was president and Midgley vice president. The many advantages of the gasoline brought some easy marketing victories. In May of that year, the top three drivers at the Indianapolis 500 powered across the finish line on ethyl gas. As a sign of the growing importance of ethyl gas, General Motors and Standard Oil of New Jersey (which held a patent on a cheaper way to synthesize tetraethyl lead) formed the Ethyl Gasoline Corporation—renamed the Ethyl Corporation in 1942—in August 1924.9 Kettering was again president; Midgley, now second vice president and general manager.
Not everything was proceeding smoothly, however. Keeping conditions safe for workers handling commercial volumes of tetraethyl lead was proving difficult. Even Midgley, aware of the risks of prolonged exposure to the additive from the outset, was not immune: he needed to spend a month in Florida in early 1923 to recover. There was a growing worry as well about the possibility of lead poisoning from the exhaust of automobiles running on ethyl gas. A few months after Midgley’s respite in Florida, General Motors contracted the U.S. Bureau of Mines to investigate the health effects of tetraethyl lead.
Then, within a single week in October 1924, five workers died at the Bayway tetraethyl lead laboratory at the Standard Oil refinery in Elizabeth, New Jersey. Black-and-blue from muscle spasms, writhing in agony, increasingly delusional and paranoid, the poisoned workers became violent and suicidal. Doctors saw little choice but to restrain the most violent in straitjackets. Confusion and denial reigned at the Bayway facility. A Bayway manager in charge of some of the men, after learning of the death of one of his men and the grave illnesses of four others, thought for a bit, then jotted down an explanation as odd as the disease itself: “These men probably went insane because they worked too hard.”10 When reports of these deaths hit the front pages of news-papers across the United States, Midgley was dispatched to reassure the public.
Earlier in the year, after witnessing firsthand the hazards of its commercial production, Midgley had considered abandoning tetraethyl lead as an antiknock agent. But, by the time of the deaths at Bayway, he was again enthusiastic, perhaps because of advance notice that the Bureau of Mines would soon conclude that the exhaust from ethyl gasoline was safe. Midgley was a natural showman. To demonstrate that tetraethyl lead was harmless in small doses, he rubbed some into his hands during a press conference at the offices of the Standard Oil Company on 30 October 1924.11 This stunt did little, however, to reassure worried state officials. That same day, the New York City Board of Health banned ethyl gasoline; the state of New Jersey and the cities of Philadelphia and Pittsburg soon followed. Sales went ahead elsewhere, although many authorities were now less than enthusiastic.
With the release of the Bureau of Mines’ report the day after Midgley’s press conference, ethyl gas received some positive news coverage. The New York Times headline on 1 November summed up the report’s findings: “No Peril to Public Seen in Ethyl Gas, Bureau of Mines Reports after Long Experiments with Motor Exhausts.” The methodology for this conclusion would later undergo intense scrutiny from other health researchers. Every day for 3 to 6 hours, bureau scientists had exposed over 100 types of animals, including monkeys, dogs, rabbits, and pigs, to leaded gasoline exhaust. After eight months of testing, the animals had shown no signs of lead poisoning (such as paralysis or loss of appetite and weight). “The danger of sufficient lead accumulation in the streets through the discharging of scale from automobile motors,” the bureau concluded, was “seemingly remote.”12
Still, with news continuing to emerge of more deaths of workers at the other two plants producing tetraethyl lead, Ethyl was now struggling to stay in business.13 The Bayway plant remained closed following the deaths in October. The media were now calling ethyl gasoline the “loony gas.” Workers at the DuPont plant in Deep Water, New Jersey, which first began producing tetraethyl lead in September 1923, were now calling their plant the “House of the Butterflies” because so many of them were hallucinating about winged insects, an early sign of lead poisoning. “The victim,” explained New York Times reporter Silas Bent in 1925, “pauses, perhaps while at work or in a rational conversation, gazes intently into space, and snatches at something not there.” Managers claimed workers in Deep Water were told to wear gloves, protective clothing, and gas masks. Still, over three-quarters were poisoned, some repeatedly, during the first year and a half of operations.14
The company took several steps to gain the public’s confidence in the face of these grisly tragedies. Ethyl, along with Standard Oil and DuPont, convinced the Surgeon General in December 1924 to request a public airing of the health effects of tetraethyl lead. Then, during the resulting conference held by the Public Health Service in May 1925, Ethyl announced it would suspend sales to allow for further studies.15 This conference gave Ethyl, Standard Oil, General Motors, and DuPont a public forum to make a case for the value of adding tetraethyl lead to gasoline. Frank Howard, a senior executive at Standard Oil, called tetraethyl lead a “gift of God” that allows “a gallon of gasoline . . . to go perhaps 50 percent further.”16 Many at the conference listened sympathetically to these arguments. Still, those attending heard enough counterarguments to decide to create a small committee under the Surgeon General to investigate the potential health effects of tetraethyl lead further.
The committee reported in January 1926. The deaths thus far, it decided, arose because of unsafe manufacturing practices: accidents that were avoidable with proper precautions. It found no hard evidence of poisoning from exposure to leaded gasoline, although it did urge the U.S. government to continue its research as “widespread” use of leaded gasoline could create “very different” conditions. The conclusion—“there are at present no good grounds for prohibiting the use of ethyl gasoline”—was a green light for the Ethyl Corporation.17
Ethyl gasoline went back on sale in May 1926. There were now stricter safety rules for manufacturing and distributing tetraethyl lead as well as signs posted at service stations along the lines of “Ethyl Gasoline containing tetraethyl lead, to be used as motor fuel only, and not for cleaning or any other purpose.”18 The company agreed as well to follow the voluntary standard set by the Surgeon General of a maximum of 3 cubic centimeters of tetraethyl lead per gallon of gasoline (equal to 3.17 grams per gallon). The Ethyl Gasoline Corporation began to advertise ethyl as an efficient gasoline sold by responsible oil companies able to enhance a car’s power while reducing vibration (sometimes without even mentioning the lead additive). Kettering and Midgley were no longer in charge. Kettering had been demoted from president to director a year earlier. Midgley had gone from being second vice president and general manager of Ethyl to simply an employee of GM. “We felt that it was a great mistake to leave the management of the property in the hands of Midgley,” GM President Alfred P. Sloan would later explain, “who is entirely inexperienced in organization matters.”19
In 2003, Thomas Midgley Jr. was inducted into the American National Inventors Hall of Fame in Akron, Ohio, for his discovery of ethyl gasoline. His entry credits him with enabling “airplane makers to develop more powerful engines, which gave the United States a decisive advantage during the Second World War. The increased engine horsepower also allowed for greater aircraft safety, reliability, and speed.”20 Adding lead to fuel no doubt enhanced the performance and efficiency of auto-mobiles and airplanes. Chemist George Kauffman estimates that tetra-ethyl lead “saved the public... one-third of the total gasoline costs that would have been paid had [it] not been discovered.”21 Yet leaded gasoline has had consequences far graver than Midgley or the Bureau of Mines or the Surgeon General could ever have foreseen.
Not all scientists agreed with the reassuring reports by the Bureau of Mines and Surgeon General in the 1920s. One of the most vocal critics was Yandell Henderson, professor of Applied Physiology at Yale University. In one speech in April 1925, for example, he damned the bureau’s findings, saying “the investigators in the Bureau of Mines have used experimental conditions which are fundamentally unsuited to afford information on the real issue.” The approach to studying the effects of acute lead poisoning may have been reasonable. But, in his view, the research on the potential long-term health effects of lead emissions from automobile exhaust was, quite simply, shoddy and misleading.
The reason, Henderson said, was straightforward: General Motors funded the bureau’s research. The findings, he explained, were really about protecting “billions of dollars” in future profits for General Motors, Standard Oil, DuPont, and the Ethyl Gasoline Corporation, not about protecting public health. These were powerful financial interests. Given this, he could see little chance that the U.S. government would ban leaded gasoline unless it suddenly began to kill large numbers of people.
“It seems more likely,” he said presciently, “that the conditions will grow worse so gradually and the development of lead poisoning will come on so insidiously (for this is the nature of the disease) that leaded gasoline will be in nearly universal use and large numbers of cars will have been sold that can run only on that fuel before the public and the Government awaken to the situation.” This would make it extremely difficult to eliminate lead from gasoline by the time authorities awoke to the dangers. Future control was, according to Henderson, the real reason for the enthusiastic corporate reaction to the discovery of tetra-ethyl lead. “It is sold now at little or no profit,” he explained. “The profit is in the future and will consist in control of the gasoline business and control of the automobile industry. The power or combination of powers that holds the patents on tetraethyl lead will be the only one that will be able to make the cars that we all want to buy.”22
A few other prominent professors and scientists were just as concerned over the use of ethyl gasoline on health grounds. David Edsall, dean of the Harvard School of Public Health, and a member of the 1925 Surgeon General’s expert committee on tetraethyl lead, called the final report “half-baked.” Alice Hamilton of Harvard University spoke repeatedly about the potential dangers of tetraethyl lead. Her views are perhaps best expressed by her comment to Kettering during a break in the May 1925 conference. Glaring at him, she blurted: “You are nothing but a murderer.” There were critics outside of the United States as well. Erik Krause at Potsdam Institute of Technology in Germany, for example, wrote a letter to Midgley calling tetraethyl lead “a creeping and malicious poison,” so deadly it killed a member of his dissertation committee.23
The counterattack against these critics was sharp. The editor of Chemical and Metallurgical Engineering, H. C. Parmelee, called them “incompetent,” “misguided zealots,” putting forth “hysterical testimony” that ignored that the research on tetraethyl lead was “in a fine spirit of industrial progress looking toward the conservation of gasoline and increased efficiency of internal combustion motors.” The efforts to counter opponents of leaded gasoline became better coordinated after 1928 with the formation of the Lead Industries Association. In the end, critics like Professor Henderson did little to slow the sales of leaded gasoline, and in an impressively fast takeover of market share, 90 percent of all of the gasoline in the United States was leaded by the 1930s.24
The Decades of Industry Science
The U.S. government didn’t follow the advice of the 1925 Surgeon General’s committee to continue to investigate the long-term health and environmental effects of widespread use of leaded gasoline. Instead, over the next four decades, research on leaded gasoline was geared toward serving industry interests.25 The most notable “industry scientist” was the toxicologist Robert Kehoe, Ethyl’s chief medical consultant from 1924 until retiring in 1958. He was also the founding director of the Kettering Laboratory of Applied Physiology at the University of Cincinnati. Opening in 1930 with a donation from General Motors, DuPont, and Ethyl, the laboratory was the world’s chief source of data on the health effects of leaded gasoline for over three decades.
The lab’s findings were consistent: leaded gasoline was in no way a danger to public health. Three core assumptions about lead grounded this conclusion. It was natural to find some lead in human blood; lead was safe below a certain threshold; and the levels in countries like the United States were far below this threshold, meaning any lead emitted from automobile exhaust was, in effect, harmless. The U.S. government became so confident in this research it agreed to raise the voluntary standard from 3 to 4 cubic centimeters of tetraethyl lead per gallon of gasoline in 1958 (equal to 4.23 grams per gallon).26 “During the past 11 years, during which the greatest expansion of tetraethyl lead has occurred,” explained the Surgeon General at the time, “there has been no sign that the average individual in the United States has sustained any measurable increase in the concentration of lead in his blood or in the daily output of lead in his urine.”27
The industry’s control over research took its first hit in 1965 with Clair Patterson’s groundbreaking analysis of the contaminated and natural levels of lead in humans in the northern hemisphere, which would be published in the September issue of Archives of Environmental Health. Patterson, a geochemist at the California Institute of Technology, first wondered about the extent of lead contamination during his work on dating the age of the earth more accurately at 4.55 billion years. The estimates in his 1965 article were alarming. Residents of the United States had concentrations of lead around 100 times higher than natural levels, while the level of lead in the atmosphere of the northern hemi-sphere was more than 1,000 times higher than natural levels. His recommendation was blunt: eliminate the main sources of lead pollution, including ethyl gasoline.28
According to Patterson, as soon as Ethyl learned of his findings—some months before they were published—it reacted by offering him “research support” to “yield results favorable to their cause” and, when he refused, by launching a campaign to discredit his results. In a review of the article for the editor of Archives, Robert Kehoe called it “remarkably naïve,” the “brash” musings of someone who knew too much about rocks and next to nothing about toxicology. Still, he would “welcome” the publication of the article, so the findings, which he felt were spreading by “word of mouth,” could be “faced and demolished.”29 Guided by Kehoe, the orthodox establishment was soon ridiculing Patterson’s research. Efforts, too, were made to block any further research by him on lead. The Public Health Service and the American Petroleum Institute cut off his research money. And pressure was put on Cal Tech to dismiss him.
A 1966 hearing of the Senate Subcommittee on Air and Water Pollution was a turning point for both Kehoe and Patterson. In the wake of layoffs and falling revenues, Ethyl was lobbying the U.S. Public Health Service to raise the amount of lead permitted in a gallon of gasoline. Kehoe was the star expert witness for Ethyl. He had, as he explained with pride to the chair of the subcommittee, “more experience in this field than anyone else alive.” The chair was obviously wary of the arrogance of Kehoe’s certainty and prodded him to explain why others, including the Public Health Service, were starting to question the accuracy of his conclusions.
Still, Kehoe didn’t waver. There was, he said, “not the slightest evidence” of harm from airborne lead, and leaded gasoline posed no risk at all to public health. But when Patterson explained his research findings to the hearing a week later, he could see little reason for Kehoe’s complacency. The public health threat from lead, he argued, was more appropriately seen on a continuum, with acute poisoning at one end and chronic low-dose poisoning at the other.30 With some in the U.S. government now listening to Patterson, other researchers were also beginning to investigate the effects of exposure to low doses of lead, especially on vulnerable groups such as children and pregnant women. After 40 years of industry control over the research on the health effects of leaded gasoline, the policy and science communities were beginning to turn against Kehoe and the Kettering Laboratory.
By 1970, the U.S. Surgeon General was calling for research to identify children with “undue” lead exposure. For the first time, the federal government also began to fund studies of the health consequences of lead for children. “The industrial monopoly on scientific data,” child psychiatrist Herbert Needleman wrote about this period, “was drawing to an end.”31
The consensus within the industry over the value of putting lead into gasoline was breaking down as well. General Motors had sold the Ethyl Gasoline Corporation to Albemarle Paper in 1962, which, being 18 times smaller than Ethyl, had to borrow $200 million to acquire it.32 Although the reasons for the sale are not fully clear, Ethyl’s flat profit line at the time was certainly a factor (Ethyl’s patent on tetraethyl lead expired in 1947), as were worries about possible antitrust investigations.
This sale left Ethyl a much weaker player in the corporate lobby of the U.S. Congress. Still, Ethyl executives felt shocked and betrayed when GM announced in January 1970 that it would install catalytic converters by 1974. Because lead destroys the platinum catalyst in the converter, cars with catalytic converters need unleaded gasoline. Later, GM would argue it had little choice, with the 1970 Clean Air Act about to set mandatory targets to decrease automobile emissions, including 90 percent reductions in carbon monoxide, nitrogen oxides, and hydrocarbons. The official biographer for Ethyl saw it differently. “It struck some people as incongruous—not to use a harsher word—for General Motors to sell half of what was essentially a lead additive firm for many millions and then advocate annihilation of the lead antiknock business.”33
Before long, other automakers were announcing similar plans to install catalytic converters. Suddenly, the future for the lead additive industry was looking grim. The chairman of the Mobil Oil Corporation, in a speech in January 1970, was blunt when explaining the thinking among automakers: “Lead must go.”34