Thomas Midgley And The Law Of Unintended Consequences

WHEN THE ARIZONA DIAMONDBACKS WON THE WORLD SERIES LAST fall, team officials rushed to thank everyone who had contributed, from the players to the owner to government officials and fans. No one mentioned the name of Thomas Midgley, yet without him, there might well be no Diamondbacks, for his two great discoveries made today’s Southwest possible. Only the hardiest souls braved Arizona’s desert heat until Midgley’s development of Freon made air conditioning commonplace. Similarly, his leaded gasoline allowed the high-performance engines that the region’s long distances and tall mountains demand. Before him, air conditioning was reserved for a few large public buildings and wealthy homeowners; owning a refrigerator required a mass of bulky and dangerous machinery in the basement; and cars couldn’t climb hills or hit top speed without sputtering dangerously.

Decades after he died, a new generation of scientists would learn that both of Midgley’s great discoveries had come with great costs attached. The gasoline that had revved up America’s cars was also dumping lead into the atmosphere, and the chlorofluorocarbons that had cooled the nation and chilled its food were also destroying the earth’s protection against the sun’s rays.

During World War II Time magazine could accurately describe him as “big, famed Thomas Midgley Jr.,” but today he is obscure. No full-length biography of him exists, and an impression of the man must be patched together from the reminiscences of those who knew him. He liked reciting “Casey at the Bat,” he stood in the wings at the Metropolitan Opera making recordings on an apparatus of his own design, he sent out Christmas cards filled with original light verse of no great merit, he financed the educations of 17 undergraduates, and in the 1920s he and his colleagues formed a drinking club whose motto, Temperance Despite Prohibition, was toasted with gin.

Throughout his career he labored in the shadow of Charles Kettering, the revered research chief of General Motors. Kettering was famous for creating the automobile self-starter, the high-compression engine, the modern diesel locomotive, and many other essential features of contemporary life. But he often said that his greatest discovery was Thomas Midgley.

The object of Kettering’s regard was born on May 18, 1889, in Beaver Falls, Pennsylvania. He was the only child of a businessman father who later invented the demountable tire rim. At the time of Thomas’s birth, Thomas, Sr., was the superintendent of a steel company in Beaver Falls; he subsequently entered the wire-goods business there. Midgley’s mother came from an inventive family as well: Her father, James Ezekiel Emerson, invented circular and band saws with removable teeth.

In 1896 the family moved to Columbus, Ohio, where Thomas’s father managed a bicycle factory and later manufactured wheels and tires. For the rest of his life, Columbus would be Midgley’s principal home. He did well in school and played on his high school football and baseball teams. In an early demonstration of his flair for research, he and a teammate tested a variety of substances to see which would make a spitball curve best. They finally settled on slipperyelm bark.

After two years at a Connecticut prep school, he went on to Cornell University, where he majored in mechanical engineering. He planned a career as an inventor but as yet had no particular interest in chemistry. Two survey courses were all the formal chemical instruction he would ever receive.

He graduated from Cornell in 1911, and in August of that year he married Carrie May Reynolds of Delaware, Ohio. The couple would have two children. He took a job as a draftsman and designer with the National Cash Register Company, in Dayton, Ohio. At the time, NCR was a leading innovator in retail and accounting equipment and one of a handful of American firms with well-funded industrial-research laboratories. Charles Kettering had been in charge of NCR’s famed Inventions Department No. 3 until 1909, when he left to found his own firm, the Dayton Engineering Laboratories Company (known as Delco), and focus on automotive research.

After a year at NCR, Midgley returned to Columbus and spent four years in charge of research for his father’s tire company. In 1916 Kettering hired Midgley to work in Delco’s research laboratory. One of the earliest problems he was assigned was engine knock, a troublesome condition that was and is characterized by an annoying “putt-putt” or “ping” sound, overheating, jerky motion, and sluggish response. The problem gets worse when a strain is put upon the engine, such as when accelerating or climbing a hill. Besides making noise and increasing pollution, knock damages engines and saps their efficiency. And the higher the engine’s compression, the worse the problem gets.

Kettering’s original interest in knock, however, was not prompted entirely by automobiles. Another factor was his firm’s Delco-Light engine, a freestanding, single-cylinder, gasoline-powered machine used mostly by farmers to generate household electricity. Because of insurance considerations and local ordinances restricting the home storage of gasoline, Kettering wanted to know if the Delco-Light could run on kerosene as well. When his staff tried it, they couldn’t get the engine to stop knocking.

To find out what the cause was, Midgley took a Delco-Light engine, replaced part of the cylinder with transparent quartz, and devised a highly ingenious apparatus—it was made from two pieces of lath, two shingle nails, and a tomato can for a film drum—to photograph the combustion process. His investigations showed that knock was caused by a buildup of pressure after ignition, as the flame traveled along the cylinder. An effective antiknock agent would inhibit this process, allowing the fuel to burn evenly all the way down.

Kettering prized a quality he called “intelligent ignorance,” an ability to think coupled with an absence of preconception. Appropriately enough, the next step in the conquest of engine knock was prompted by Kettering and Midgley’s ignorance of chemistry. They suspected that the reason kerosene knocked in the Delco-Light but gasoline didn’t was gasoline’s higher vapor pressure. With little scientific basis, they guessed that dyeing kerosene with a dark color would make it absorb radiant heat more easily and thus vaporize more readily.

Midgley and Kettering settled on red as the most promising color. Their reason, as Kettering wrote, was that “we both happened to know that the leaves of the trailing arbutus are red on the back and that they grow and bloom under the snow.” On December 2, 1916, Midgley went to a chemical laboratory at Delco looking for an oil-soluble red dye. None was available, but a laboratory worker told him that iodine would dissolve in oil, a fact of which Midgley, the future president of the American Chemical Society, had been unaware.

When Midgley added iodine to his test engine’s fuel, the knocking stopped. Further study showed that the color was irrelevant, for other red dyes had no effect, while colorless iodine compounds stopped the knocking. Unfortunately, iodine was too expensive for general use. Still, the discovery was important, for it established a crucial point: Knock could be eliminated by altering the fuel rather than redesigning the engine.

The problem rested there for the next two years. With America’s entry into World War I, in 1917, Midgley shifted his research to synthetic aircraft fuels. He also worked on Kettering’s “Bug,” a pilotless plane filled with explosives that was meant to serve as a guided missile. In both cases, the war ended before any results could be put to military use.

After the war Midgley resumed his antiknock work with new urgency, for the world was facing its first fuel crunch. Automobile ownership was increasing rapidly, and experts predicted that less than a two-decade supply of petroleum remained (though newly discovered oil fields would soon ease the crisis). As refiners struggled to convert a larger share of each barrel of oil to gasoline, the average volatility of gasoline kept getting lower, which made the knocking problem that much worse.

Although Midgley’s success with iodine had been promising, it offered no clear pathway for further research. Hundreds more substances were tested without success. On the last day of 1918, General Motors acquired United Motors, a loose collection of companies that included Delco. The acquisition put pressure on Delco’s researchers to produce results that would be profitable. Kettering told Midgley’s team, “By God, if you don’t come up with something within the next three to six months you’re all fired.”

Not long after Kettering’s ultimatum, on January 30, 1919, Midgley’s assistant Thomas A. Boyd discovered that aniline offered knock resistance better than that of iodine. Unfortunately, its odor was unbearable, and adding scents such as pennyroyal and citronella was no help. Midgley wrote, “I doubt if humanity, even to doubling their fuel economy, will put up with this smell.” Nevertheless, Boyd’s results were enough to keep the research effort going.

Another case of serendipity led to the next breakthrough. While traveling in 1921, Kettering (who by then was a vice president of GM and in charge of research) read about selenium oxychloride and thought it might work as an antiknock additive because it was similar to the other compounds Midgley was testing. When tried out by Midgley, it proved to be corrosive to metals. But from there the path led to better compounds of selenium, then to tellurium, and finally to diethyl telluride, which in an April test proved 24 times as effective as aniline. Still, tellurium was no answer, since it was unavailable in quantity and stank with an odor resembling garlic. Seventeen years after the experiments with tellurium ended, when the time came to write a history of the project, Boyd found that the records of the work still stank.

Encouraged nonetheless, Midgley took the results of his group’s efforts, charted them on a modified periodic table of the elements, and discovered trends in antiknock activity up and down the various groups. This insight allowed him to abandon what he called the “Edisonian method” —trying everything in the stockroom—for a systematic approach, turning what had been a wild-goose chase into a “scientific fox hunt,” as he put it. Twenty-three carefully targeted compounds were created and tested in 15 weeks. During a visit to his father in Massachusetts in October, he had the latest results telegraphed to him daily.

Attention soon centered on the carbon-group elements. Results from other groups had shown that the heavier elements tended to inhibit knock more efficiently, so Midgley began with tin. Its ethyl derivative “exhibited a much more powerful effect than had been expected,” he later wrote. The periodic table suggested that lead would be even more effective, and indeed it was.

On December 9, 1921, Midgley’s coworker Carroll Hochwalt prepared and tested a small quantity of tetraethyl lead (TEL). “It was eureka,” Hochwalt recalled. TEL provided full knock resistance with only one part in 1,360—less than an ounce in 10 gallons of gasoline. Midgley had finally found the additive he had been searching for: cheap, odor-free, and effective even in tiny amounts. Years later, salesmen demonstrating the product would pour a few drops of TEL onto a piece of cloth and wave it in front of the air intake of a knocking engine. The noise instantly stopped.

Kettering dubbed the new additive Ethyl. The first Ethyl gasoline went on sale in February 1923 at a station in Dayton, where GM had a pilot plant. In April GM formed the General Motors Chemical Company (GMCC) to produce and market TEL. The following month the company won valuable publicity when the first three finishers in the Indianapolis 500 all ran on Ethyl gas. The price of Ethyl was three cents per gallon more than regular, and it was dyed a distinctive red color (ironically, considering the origin of Midgley’s first breakthrough) so that customers would know they were getting what they had paid for.

In August 1924 the Ethyl Gasoline Corporation was established as a joint venture between GM and Standard Oil of New Jersey, which had developed its own production process for TEL that was cheaper and more efficient than the one GM was using. The new corporation took over the assets of GMCC and installed Kettering as president and Midgley as vice president and general manager. DuPont, which had adapted Midgley’s laboratory discovery to industrial production, would be in charge of manufacturing. (DuPont was closely intertwined with GM in the 1920s. It held 38 percent of GM’s stock by 1920, and the presidents of the two corporations, Pierre du Pont of GM and Irénée du Pont of DuPont, were brothers.)

Some hurdles remained, most prominently safety. The poisonous nature of lead had been known since ancient times, but most authorities believed that when TEL was dispersed in the atmosphere, it would pose no health hazard. Workers, however—including drivers, manufacturing employees, and garage attendants—faced a more concentrated dose, which raised some concern among public health experts.

Even Delco’s laboratory researchers had developed health problems. Hochwalt recollected, “We all had lead poisoning.… You could see the lines of lead in the bones [with X-rays], but it disappeared. I used to get nauseated over food.… Midgley had it, too.” Midgley took off the month of February 1923 to recover. Hochwalt used his six-week honeymoon. During 1923 and 1924 Kettering and GM hired medical consultants to evaluate TEL. They reported no insurmountable problems, and the company went ahead with its expansion. Then disaster struck.

On October 22, 1924, workers at Standard Oil’s TEL plant at Bayway, New Jersey, started falling ill. By October 31, five had died, and at least 35 others were hospitalized. A report summarized the symptoms: “The patient becomes violently maniacal, shouting, leaping from the bed, smashing furniture and acting as if in delirium tremens; morphine only accentuates the symptoms.… In two fatal cases, the body temperature rose to 110 degrees just before death occurred.” The deaths made the front page of The New York Times .

The previous month, DuPont chemists visiting Bayway had been “greatly shocked at the manifest danger of the equipment” and the “inadequate safety precautions.” After the accident the Bayway plant was shut down. Standard Oil officials assured the public that they were correcting the mistakes made there.

Not long afterward, however, six men died at a DuPont-run TEL plant in Deepwater, New Jersey, that used a supposedly safer process. Workers called the Deepwater plant the House of Butterflies, for the hallucinations induced by the lead compound. Around the same time, one researcher died and four were hospitalized after breathing concentrated TEL vapors at a Standard Oil laboratory in Elizabeth, New Jersey.

In April 1925, in reaction to the workers’ deaths and other growing pains, Kettering was removed as president of Ethyl. Early the next month the company suspended sales of TEL until its safety could be established. A few weeks later U.S. Surgeon General H. S. Gumming convened a conference on its hazards.

Kettering testified that the additive was essential to stretching fuel supplies. Midgley called his creation “not so much a dangerous poison as it is a treacherous one.” It was unsafe, he said, only when improperly handled, a circumstance that was already being remedied. Frank Howard of Standard Oil called TEL a “gift of God,” which prompted the labor leader Grace Burnham to reply that it had been no gift of God for the workers.

Cumming appointed a committee of prominent physicists, chemists, health experts, and others to investigate. In January 1926 the committee reported mild health effects from the use of lead, but nothing drastic enough to justify a ban. TEL was dangerous only in concentrated form, the report said, not when diluted in gasoline. If mixing was performed at distribution centers instead of at the point of purchase, and if extra precautions were taken to protect the health of workers, there would be no cause for concern. Filling-station owners scrapped their Ethylizers and installed separate pumps, and in May 1926 Ethyl gas went back on sale. A few critics remained, most prominently Alice Hamilton of Harvard, a founder of the field of public health. She called TEL “a probable risk to garage workers and a possible risk to the public.” Most people, however, accepted the committee’s findings. Increased ventila- tion and other plant improvements reduced the workplace hazard to a level considered acceptable by 1920s standards.

Before and during the hiatus, Ethyl executives had taken action to address another problem: TEL caused engine damage by depositing a film of lead oxide on valve surfaces. The best corrective was to add ethylene dibromide; it “scavenged” lead by converting it into lead bromide, which passed out with the exhaust. But adopting it as a cure would require large amounts of bromine, which was then produced only as a byproduct from brine wells. Early in 1924 Kettering and Midgley visited the offices of Dow Chemical, the nation’s largest supplier of bromine, in Midland, Michigan, to see if it could be made available in the quantities fhev would need.

Dow officials told Kettering and Midgley that the company could meet their immediate requirements, but if sales of Ethyl gas took off, new supplies of brine would be needed. Ethyl and Dow responded by exploring brine sources from Ohio to Mexico to North Africa and even the Dead Sea. None were promising. Just when TEL was looking like a miracle, another frustrating roadblock had appeared.

Kettering and Midgley took their concerns to Herbert Dow, the company’s founder. Dow called attention to the biggest brine source of all, the world’s oceans. Realizing that seawater contains 67 parts per million of bromine, he speculated that it might be possible to concentrate it cheaply by evaporation in some arid place. Midgley joked that they could just pump the Pacific Ocean over the Rockies and let it dry out.

More practically, Midgley came up with a laboratory process for extracting bromine from seawater, but his company lacked the expertise to scale it up to production levels. To demonstrate the method’s practicality, Kettering responded in typically direct fashion: He bought a 254-foot cargo ship, renamed it Ethyl , and loaded it with bromine-extracting equipment and technical staff. The whole enterprise cost about $500,000. In April 1925 the ship set sail into the Gulf Stream off the Virginia capes.

Beyond proving that Midgley’s method worked, little was achieved. Only 100 pounds of bromine were extracted, and most of the staff spent the journey violently seasick. But Kettering had made his point: If Dow would not extract bromine from seawater, he would. Dow eventually adopted a version of Midgley’s process, modified by its own chemists, and supplied the bromine through a joint venture called the Ethyl-Dow Chemical Company, of which Midgley was appointed director. In 1934 Ethyl-Dow opened a plant on the North Carolina coast that extracted 9,000 tons of bromine a year. By 1941 worldwide production was 40,000 tons a year, 90 percent of which went into TEL-treated gasoline.

As use of TEL spread, automakers, led by Chrysler, began designing cars with high-compression engines. Oil companies introduced antiknock ingredients of their own, generally more expensive or less effective than TEL, and adopted innovative refining techniques, such as thermal and vapor-phase cracking. In 1925 and 1926 a host of TEL-free antiknock gasolines came on the market: Gulf No-Nox, Sinclair H-C, Super Shell, and many others. Improvements in refining would eventually increase gasoline’s performance much more than TEL alone could. But TEL still gave a boost to even the highest of high-test, and there was no denying that it was the advance that had ienited the fuel revolution.

In 1929, the first year the Ethyl Gasoline Corporation paid a dividend, less than 7 percent of the gasoline sold in America contained TEL. That same year, Ethyl abandoned its exclusive contracts and began selling TEL on the open market, and a decade later the proportion was close to 80 percent. Ketterine later estimated that two gallons of gasoline with TEL provided as much usable energy as three gallons without. This meant that in the quarter-century following its introduction, TEL had saved a billion barrels of oil. Nearly as important, it had made Tom Midgley a chemist.

When the GM Corporation moved its laboratories to Detroit in 1924, Midgley stayed behind in Ohio, resigning from GM to work for Ethyl and as a consultant. He shifted his research focus to rubber chemistry, an area he had first investigated at his father’s tire company. Kettering saw tires as an automobile’s weakest link: They wore out quickly and were expensive, especially after the price of natural rubber jumped from 23 to 90 cents a pound. Seeking a substitute, in 1926 GM allotted $60,000, one-sixth of its total research budget, to fund Midgley’s work in synthetic rubber. The next year the company gave another $50,000, and a smaller subsidy the following year paid for Midgley’s group to continue its research at Cornell University.

The effort proved frustrating, since Midgley made little progress at first. Most of the main concepts were covered by German patents. After his string of papers related to engine knock between 1920 and 1925, Midgley published nothing during the next three years. Then, from 1929 to 1937, he produced several papers per year on rubber, with Albert L. Henné as his chief collaborator. The two uncovered a great deal of information about such things as molecular structures, chain lengths, and the chemistry of vulcanization, very little of which had any commercial application.

In 1928, in the midst of all this work, Kettering, who always had a commercial eye out, drafted Midgley for one more task: the search for a better refrigerant. The most common one then in use was ammonia, which was toxic and potentially explosive. The two main alternatives, methyl chloride and sulfur dioxide, were little better. In 1929 a leak in the methyl chloride refrigeration system killed more than 100 people in a Cleveland hospital. Existing refrigerators were bulky, expensive, and unreliable as well; iceboxes were still the norm for home use.

GM’s involvement in refrigeration had begun in 1918, when its founder, William C. Durant, bought the Guardian Frigerator Company, of Detroit. The following year Durant renamed the firm Frigidaire Corporation and sold it to GM, and in 1920 he moved it to Dayton. Frigidaire lost $2.5 million the next year, for the market was still tiny. Only 5,000 refrigerators were built in the United States, of which just 365 were Frigidaires. As the decade wore on, Frigidaire became modestly successful, but Kettering knew that an improved refrigerant would greatly increase sales of refrigerators—not to mention air conditioning, a business the company was preparing to enter.

Midgley, happily pursuing his rubber work, was reluctant to get involved. According to Kettering, “it took a whole Saturday afternoon to sell Midge on the idea that this was quite an important project.” Perhaps Midgley was remembering the long, hard slog that had led to his discovery of TEL, but compared with that effort, refrigerants proved virtually a walk in the park. Boyd, Midgley’s co worker, wrote that Midgley “set the course and went almost straight to it without side trips or detours.” All the important laboratory work was done in the fall of 1928 at Ohio State University’s laboratories in Columbus. By one account, after analyzing the available data and planning a course of research, Midgley’s team came up with the desired compound in only three days.

Once again, Midgley began with the periodic table. A quick survey of known refrigerants showed that they all were compounds of hydrogen, carbon, nitrogen, oxygen, sulfur, and the halogens. Within this set of compounds, flammability decreased from left to right on the table, while toxicity decreased from bottom to top. The two trends pointed to fluorine as a promising candidate.

These results were surprising, since fluorine had a nasty reputation among chemists. Many of its compounds are poisonous. While sodium chloride is table salt, sodium fluoride is an insecticide. Hydrofluoric acid dissolves glass. Nonetheless, Midgley presented his findings to Kettering’s staff. Some in the room voiced objections, but Kettering was characteristically empirical. “Well, I don’t know,” he said. “I think we ought to try it.”

The available data suggested a high degree of stability for carbon-fluorine bonds, so compounds of those two elements looked particularly appealing. Midgley went into the laboratory with Albert Henne and set about synthesizing compounds of carbon, fluorine, and other halogens or hydrogen. Each compound they made was tested for boiling point, flammability, and other physical properties, as well as toxicity.

The research uncovered a number of promising compounds, the best of which was dichlorodifluoromethane (CF 2 Cl 2 ), later dubbed Freon 12, or simply Freon. Its success led to a whole class of compounds known as chlorofluorocarbons (CFCs). Freon was ideal as a refrigerant because it had a boiling point in the middle of the desired range and was nontoxic and nonflammable.

Midgley demonstrated the latter two properties to his colleagues with a dramatic demonstration at the 1930 meeting of the American Chemical Society (ACS). He carried to the stage a small vial of Freon and a candle, which he lit. He then poured the Freon into a bowl, waited for it to boil, breathed in a lungful of the vapors, and gently exhaled them toward the flame. It went out. With a single act, he had shown that Freon was neither poisonous nor flammable.

He added another executive position to his collection in 1930 when GM and DuPont formed a joint venture to market CFCs, as had been done with the Ethyl Gasoline Corporation (for TEL) and would soon be done with Ethyl-Dow (for bromine). The new firm was called Kinetic Chemicals, Inc., and Midgley was named vice president. Kinetic’s business would turn out to be even more lucrative than it had seemed at first, for besides being the basis of modern refrigeration and air conditioning, Freon found another application that had never occurred to Kettering or Midgley.

During World War II the Army discovered that Freon made an ideal vehicle to disperse insecticide sprays in soldiers’ barracks. After the war CFC propellants were very widely used in aerosols, ranging from paints to deodorants—one of innumerable civilian applications of World War II technology. This application released into the atmosphere far greater quantities of CFCs than refrigeration and air conditioning, which are closed systems that recycle fixed amounts. The consequences of this profligacy would not become known until decades later.

After his second great success, Midgley returned to rubber research in Columbus. He funded it in part with his own money and continued to produce solid but uncommercial results. Business considerations were less of an issue now, since after the CFC project he had no further association with GM except as an executive of the joint ventures.

Along the way he had taken up golf for relaxation, and in typical fashion he started out by studying books and interviewing experts on the mechanics of the swing. According to Kettering’s recollection, “The result was that in a short time his golf score was down in the low 70s,” an accomplishment that, if true, would be nearly as impressive as anything he did in his chemical career.

After 1937 Midgley re- tired from laboratory work, and in 1940 he became vice president of Ohio State’s research foundation. In those years he and his wife lived in a Colonial-style house in Worthington, Ohio, modeled on Mount Vernon and set on an 80-acre property with a barn and orchards. Midgley’s interest in nature led him to study the structure of anthills; his interest in golf led him to experiment with grasses for putting greens.

One day in the fall of 1940, he left an American Chemical Society gathering in Detroit to have lunch with his son in a nearby suburb. Not long afterwards he told his daughter-inlaw that he felt terribly ill, and his driver took him back to Columbus. By morning he was paralyzed from the waist down. The diagnosis was polio.

He never recovered. For a while he was confined to an iron lung. After being released from it, he worked from a groundfloor room in his home that also served as his office and bedroom. When he accepted the Priestley Award from the American Chemical Society in 1941, he had to be carried to the stage on a stretcher. During World War II he chaired a committee on classified research and struck up a correspondence with President Franklin D. Roosevelt about their shared affliction. And he remained active with the ACS, of which he had been a director since 1930 and chairman of the board of directors since 1934. In 1944 he was chosen as president.

In the fall of that year, he delivered a paper called “The Future of Industrial Research” by telephone to an industry forum. A few weeks later he met a sudden and shocking end. He disliked being lifted out of bed to his wheelchair, so he had used his training as a mechanical engineer to design a harness and a system of pulleys that allowed him to move about unaided. On the morning of November 2, 1944, his wife found him hanging from his contrivance, strangled to death. It seems to have been an accident, although some in his family speculated that he may have committed suicide. If so, he left no explanation.

Midgley’s quiet, purposeful life is suffused with irony. His antiknock compound was created as a conservation measure to remedy an expected fuel shortage, but by the time it was introduced, the world was awash in newly discovered oil. Most of the extra pop that Midgley’s additive produced went not to better mileage but to quicker acceleration. The health effects of putting all that lead into the environment were largely ignored, and in the end Midgley’s conservation measure was superseded by an environmental one. The catalytic converter was introduced in the late 1960s to cut down on harmful exhaust emissions. Leaded gas ruined catalytic converters, so it had to go, replaced by sophisticated refining methods that produced high-power gasoline without the need for additives.

A similar fate awaited CFCs. The June 28, 1974, issue of Nature carried a three-page article, “Stratospheric Sink for Chlorofluoromethanes: Chlorine Atom-catalyzed Destruction of Ozone,” by Mario J. Molina and F. S. Rowland of the University of California, Irvine. Under normal conditions, the article stated, CFC atoms are extremely stable. But when they enter the upper stratosphere, they face levels of ultraviolet radiation far higher than those on earth, causing them to decompose. The decomposition releases chlorine, which in turn converts ozone (O 3 ) to oxygen (O 2 ), thus diminishing the earth’s protective ozone shield.

The prospect, as developed by Molina and Rowland over the next few years, was grim. Their low-end hazard was sobering: Even a 5 percent loss of ozone would eventually mean 40,000 additional cases of skin cancer each year in the United States alone. And if CFC use continued, they foresaw an eventual 30 to 50 percent ozone loss. The prospect was scary enough that it even got through to the world’s government leaders. The United States ended its use of CFC propellants in 1978, and the Montreal Protocol, signed by 24 nations in 1987 (since then 152 more have joined), set 1996 as the phaseout for CFC production in the developed world.

If Midgley had lived long enough to see his inventions discredited, he could have pointed out that by spurring research into high-compression engines, TEL had done more to conserve fossil fuels than anything that had come before it, and that during World War II high-octane aviation fuel had given the Allies a critical edge in the air war. Of CFCs, he might have observed that he had not created them for use as propellants, and in any case, when they were invented, little was known of the ozone laver. Moreover, their destructive effect stemmed from the peculiarly unfortunate fact that they were exactly the right weight to get trapped in the ozone layer. Any heavier, and they would never have reached it; any lighter, and they would have passed right through.

From our experience with Mideley’s inventions, as well as other wonder chemicals such as DDT, we now have a greater appreciation of the need to take environmental matters into account when assessing the impact of a new technology. Yet just as DDT saved thousands of lives before it was banned, so too were TEL and Freon responsible for great improvements in our daily existence. Technologies, like everything else, tend to develop in ways that were never expected at the start. Midgley’s discoveries, like his entire life, exemplify both the positive and negative aspects of this simple truth.