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4: Tetraethyllead - Toxicity

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    Throughout 1922, as the first plans were made to develop tetraethyl lead, Midgley had received an alarming letter from Charles Kraus of Pottsdam in Germany. Kraus had worked on tetraethyl lead for many years and called it "a creeping and malicious poison" that had killed a senior scientist at his university.

    Another warning came from a lab director in the Public Health Service (PHS), who had heard about tetraethyl lead and wrote an October, 1922 memo to the assistant surgeon general warning of a "serious menace to public health." Several other memos traded hands and in November, Surgeon General Hugh Cumming wrote to Pierre S. du Pont about the public health question. The Surgeon General's letter was referred to Thomas Midgley, who responded on December 30, 1922 that the problem "has been given very serious consideration .. although no actual experimental data has been taken."

    In March 1923 Thomas Midgley had almost returned to normal after fighting a winter-long battle with lead poisoning. He and three other lab employees had experienced "digestive derangements, subnormal body temperatures and reduced blood pressure" from handling tetraethyl lead. He later wrote,"After about a year's work in organic lead I find that my lungs have been affected and that it is necessary to drop all work and get a large supply of fresh air."

    Despite his own condition, Midgley was nonchalant about the dangers of tetraethyl lead. In a December 2, 1922 letter to A.W. Browne at Cornell, who had been contracted for some analytical work, Midgley said that tetraethyl lead was irritating to the skin and should not be breathed or taken in the mouth.

    He added: "It would not surprise me if in the course of using tetraethyl lead for a year that some of your men would experience a slight case of painter's colic. This is nothing to worry about as several of our boys have it."

    While in Miami recovering from lead poisoning, Midgley also wrote to an oil industry engineer that poisoning of the public was "almost impossible, as no one will repeatedly get their hands covered in gasoline containing tetraethyl lead - it stings and burns... The exhaust does not contain enough lead to worry about, but no one knows what legislation might come into existence fostered by competition and fanatical health cranks."

    Apparently unconvinced by Midgley's December 30, 1922 response to their inquiry, the PHS decided that an investigation was necessary and contacted the Bureau of Mines. Midgley and Kettering were familiar with the Bureau of Mines petroleum experts based in Pittsburgh, Pennsylvania, and had also asked them to perform a health study of Ethyl gasoline around the same time. Bureau employees felt that the agency was in an uncomfortable position. In June, 1923, A.C. Fieldner, a bureau chemist, said that an investigation would be inadvisable: "The relations of the Bureau of Mines with some of the gasoline interests or motor interests will be imperiled regardless of our decision in the matter. The results promise to be so doubtful, the investigation will take so much time and cost so much money and chances for getting into trouble with some commercial interests are so great that I believe it is inadvisable to take on this investigation."

    Yet in September, 1923, an agreement was finalized between GM Research Corp. and the Bureau of Mines in Pittsburgh. The bureau agreed to Kettering's demand that it "refrain from giving out the usual press and progress reports during the course of the work, as [Kettering] feels that the newspapers are apt to give scare head- lines and false impressions before we definitely know what the influence of the material will be.

    "Kettering and the bureau were so worried about the press that all official correspondence used the trade name Ethyl rather than the word "lead" to avoid leaks to the newspapers, "as this term is apt to prejudice somewhat against its use," according to the superintendent of the Pittsburgh field station. The contract also specified that manuscripts of all reports were to be submitted to GM "for comment, criticism and approval."

    The actual tests began in the fall of 1923 with a small Delco motor provided by GM.. Various animals were exposed to Ethyl gasoline exhaust from the motor. One dog exposed to the fumes gave birth to five puppies in the test chamber "without harm of any kind," Boyd later wrote. The dogs were called the "Ethyl Gas Hounds."

    Meanwhile, on June 23, 1924, GM. president Alfred Sloan, "gravely concerned about the poison hazard," and reeling from two tetraethyl lead deaths in Dayton and one in Deepwater, approved the formation of a medical committee with W.G. Thompson of Cornell University, a consulting physician to Standard Oil, as chairman. A few days later, Irenee du Pont wrote to Sloan saying that the development of tetraethyl lead "may be killed by a better substitute or because of its poisonous character or because of its action on the engine."

    The medical committee issued a report described as negative and highly cautionary on August 20, 1924 and Irenee du Pont reassured Sloan: "I have read the doctors report and am not disturbed by the severity of the findings." Nitroglycerin was even more hazardous to make, and lead dust from car exhaust would be only a fraction of that from erosion of paint, he said.

    Thus, even as GM. and Standard were about to form a partnership and greatly expand Ethyl's role in the gasoline market, its fate was still quite uncertain. What propelled these enormous corporations to take such risks? A note from Midgley to Kettering on March 2, 1923 shows that both were aware of the enormous potential profits in tetraethyl lead. "The way I feel about the Ethyl Gas situation is about as follows: It looks as though we could count on a minimum of 20 percent of the gas sold in the country if we advertise and go after the business - this at three cent gross to us from each gallon sold. I think we ought to go after it as soon as we can without being too hasty... "

    With gasoline sales around eight billion gallons per year, 20 percent would represent two billion gallons, and three cents gross would bring in $60 million per year. With the cost of production and distribution less than one cent per gallon of treated gasoline, more than two thirds of this would be annual gross profit. As it turned out, these original figures dancing through Midgley's mind were modest compared to the market success that would come later.

    The manufacturing efforts got under way in 1923 and 1924. The first was a small G.M. operation in Dayton, Ohio, which made 7 gallons of tetraethyl lead each day.

    When the two workers on the assembly line packing the bottles died in April, 1924, the line was shut down. Kettering later blamed the lack of safety on the workers themselves."We could not get this across to the boys," he said. "We put watchmen in at the plant, and they used to snap the stuff [pure tetraethyl lead] at each other, and throw it at each other, and they were saying that they were sissies. They did not realize what they were working with."

    The second and by far the largest manufacturing operation was built at du Pont's dyestuffs division in Deepwater, N.J. Du Pont began with a 100 gallon per day unit in August of 1923, and increased production in the summer of 1924 to 700 gallons per day. A second 1,000 gallon per day began operations in January, 1925. On September 21, Frank W. Durr, a 37-year-old process operator who had worked for 25 years for du Pont, became the first of eight du Pont employees to die of lead poisoning, three more died over the summer and fall of 1924 when production was stepped up; and four more died in the winter of 1925 in the new unit. Workers who were aware of the effects of tetraethyl lead called the factory the "House of Butterflies" for the hallucinations they experienced.

    The third and smallest manufacturing unit was a 100 gallon per day "semi-works" built in the summer of 1924 at the Standard Oil of N.J. refinery in Bayway, N.J. It began operations in September, 1924 and shut down in October after five workers died and 44 others were hospitalized.

    In the months preceding this disaster, as GM. and DuPont struggled to bring the new product on line, an internal controversy erupted over worker safety standards in manufacturing, the possibilities of alternatives. When construction began on the large scale du Pont plant, in April of 1923, Irenee du Pont wrote, "It is essential that we treat this undertaking like a war order so far as making speed and producing the output, not only in order to fulfill the terms of the contract as to time but because every day saved means one day advantage over possible competition..." The competition was not from other sources of tetraethyl lead but rather other types of antiknock additives and refining processes which were beginning to come into the market.

    Demand for Ethyl fluid grew rapidly in 1923 and skyrocketed in January 1924 when GM signed exclusive contracts with Standard of New Jersey, Standard of Indiana, and Gulf Oil Co. to distribute the new antiknock fluid on the East Coast, the Midwest and the South, respectively. The contracts stipulated that adding three grams of Ethyl fluid per gallon would have the same antiknock effect as adding 40 percent benzene.79

    Du Pont had continual problems meeting increasing demands for tetraethyl lead through its bromine-based process. In June 1924 Kettering complained that the "whole program is prejudiced" because du Pont was moving too slowly. Yet two GM workers died in the spring of 1924, and the Dayton staff was said to be "depressed to the point of giving up the whole tetraethyl lead program.".

    Standard, meanwhile, had developed and patented a new kind of tetraethyl lead manufacturing process that employed ethyl chloride rather than bromine. GM chairman Sloan believed that competition would help hold du Pont back from potential price in- creases in the future and that the Standard patent position would force concessions from GM. in any event. According to court testimony in later years, du Pont officials were unaware that GM. was about to begin a joint venture with Standard that would create the company called the Ethyl Gasoline Corp. in August, 1924 with Kettering and Midgley as president and vice president.

    Standard's chloride process was slightly cheaper than du Pont's original bromide process by about four cents per pound of pure tetraethyl lead. Diluted 1,200 times in gasoline, the retail level difference would be one-twentieth of a cent ($0.0005) per gallon of gasoline.

    However, the chloride process involved higher temperatures and pressures, which made it far more dangerous than the bromine process that had already killed six or seven workers and poisoned hundreds of others. Du Pont engineers had serious reservations when G.M. decided to allow Standard Oil Co. to build a tetraethyl lead plant using the chloride process at their refinery in Bayway, New Jersey, as the du Pont internal history emphasizes.83

    Because du Pont Corp. owned one third of G.M. stock and was a partner in everything G.M. did, Du Pont engineers felt they had a right to insist that manufacturing be kept in one place for safety's sake, especially considering the severe safety problems they already faced.

    When du Pont's use of the new chloride process came up for consideration in the spring of 1924, a du Pont engineering committee insisted on approaching it with the idea of a closed system. Du Pont engineers wanted to keep the entire series of highly volatile chemical reactions closed off and isolated from workers from start to finish. Planning began in April, 1924 and construction began in September, 1924, but the du Pont ethyl chloride plant did not start operating until January, 1925. In contrast, Standard took less than three months to design, build and begin operating the Bayway, N.J. plant, beginning in June 1924.

    As demand accelerated in the summer of 1924, du Pont stepped up the older bromide production line from around 200 gallons per day to 400 in June, then 500 in July, and then 700 by August. As a result, three more workers died with wild and violent hallucinations.

    The internal controversy came to a head when a delegation of du Pont chemists led by W. F. Harrington visited Standard's Bayway plant in September, 1924. The contrast between the du Pont approach and the Standard approach was evident from the moment Harrington and his team walked through the door. They saw a large, open factory floor with three main work areas. In the first area, a large iron vessel shaped like two ice cream cones stuck top to top was rotating on its side. From within the vessel came the muffled sound of heavy explosions as sodium reacted violently with ethyl chloride and lead. As the double cone rotated, steel agitation balls churned through the boiling sodium to ensure proper mixing. When the reaction calmed down, a crane moved the double cone to the second work area, where workers unbolted the hatches over the narrow ends, releasing concentrated fumes from inside. They attached steam lines and condensers, and tetraethyl lead was distilled in much the same way that whiskey is distilled from a vat of beer.

    When the distillation was over, workers opened the iron vessel once again and scraped the steaming, leftover lead mush through a grate in the floor with shovels, gloves and boots. As the mush went through the grate, workers recovered the steel balls that would be used to agitate the next batch.

    The du Pont engineers were "greatly shocked at the manifest danger of the equipment and methods [and] at inadequate safety precautions," but their warnings were "waved aside."

    When Kettering and Midgley asked du Pont to adopt Standard's process in order to speed up production, Harrington refused. "I personally thought it was too dangerous a process for us to use," he said, and got permission in the summer of 1924 to proceed with a far safer design. The du Pont design used a closed system with ventilation for the workers. There was also a stationary reactor with permanent agitators, a contained transfer system to a distillation unit in the floor below, and finally a contained recovery system for the leftover sludge.

    Irenee du Pont felt that, had the company been given more time, the more dangerous ethyl chloride process could have been made even safer. "In due course the more dangerous trip [technical development] could have been made safe, but it was an expensive trip to have tried it more or less prematurely in the hands of novices," du Pont said. He believed that Standard (the "novices") had made a serious error of judgement. "Notwithstanding ... foreknowledge of the peril, the precautions taken in the small manufacturing operation at Bayway were grossly inadequate."

    Another reflection of the tone of the internal controversy was this statement by a General Motors attorney:

    "They [Standard] put up a plant that lasted two months and killed five people and practically wiped out the rest of the plant. The disaster was so bad that the state of New Jersey entered the picture and issued an order that= Standard could never go back into the manu- facture of this material without the permission of the state of New Jersey. In fact, the furor over it was so great that the newspapers took it up, and they misrepresented it, and instead of realizing that the danger was in the manufacture, they got to thinking that the danger was exposure of the public in the use of it, and the criticism of its use was so great that it was banned in many cities and they had to close down the manufacture and sale of Ethyl.... "


    The lead poisoning deaths of the first workers in Dayton, Ohio and Deepwater, N.J. had not attracted attention. But when the first Standard Oil Co. worker died on October 22, 1924, the Union County, N.J. medical examiner called for an investigation into the mysterious gas that was driving workers crazy. Within a few hours, GM.'s carefully contained secret had become front page news across the nation. To make matters worse, the chief chemist at the refinery told reporters: "These men probably went insane because they worked too hard."

    The following day, as another man died and some 40 more were hospitalized, Yandell Henderson told reporters that the mystery gas was "one of the most dangerous things in the country today," and was being produced without regard for public health.

    As four more workers died, Standard Oil Co. directors were "in a blue funk over the whole thing," Kettering said later. "The directors were very much afraid about it. They didn't know what was going to happen to them."

    Standard issued only short, guarded comments. Telegrams flew between Kettering, who was then in Paris, and Standard headquarters in New York. Meanwhile, New Jersey authorities banned leaded gasoline; then state legislatures in New York, Pennsylvania and others in New England condemned the new additive and forced gasoline dealers to take it off the market. The bright future for G.M. 's new invention lay in ruins. The effect was "disaster -- sudden, swift and complete," said du Pont's history of the incident.

    The New York Times said on October 31, 1924: "In all the history of chemistry, no case like this is recorded. Laboratory workers, of course, have been killed before now, but in each instance the number has been small, and usually they have died while experimenting with known explosives or seeking to find new ones. The Bayway disaster has many entirely novel features... For many days workers showed no signs of illness. The fumes evidently were cumulative in their effects ... (and) mental disturbance ... soon turned to outright mania with wild and violent delirium in the worst cases."

    GM insisted that the Bureau of Mines now make public its report, and on October 31 the bureau issued a statement concluding that the danger of the public breathing lead in the exhaust of automobiles is "seemingly remote" based on observations of animals exposed to leaded gasoline exhaust. Critical reaction came almost immediately from the scientific community. The bureau kept animal cages well ventilated and did not allow lead dust to accumulate said critics from Harvard Medical School, and this avoided real-world conditions.

    The first indication that something was seriously amiss in the way industry scientists had measured lead problems came in 1965 with an article by Clair Patterson in the Archives of Environmental Health. A Cal Tech geochemist, Patterson worked on the Manhattan project in WWII and studied issues surrounding geological date estimates. In the process of establishing the age of the earth, he noticed heavy lead contamination. People were carrying over 100 times the natural level of lead in their bodies and the atmosphere contained over 1,000 that amount, he estimated. Analyzing 1,600 year old bones of pre-Columbian humans, Patterson showed that 20th century lead burdens were seriously elevated.

    Another scientist who studied the effects of lead exposure in children was Herbert Needleman. His work showed a direct correlation between hypertension and other nerve disorders and the level of lead in children’s bodies.

    The levels of lead in the human body are usually measured by blood samples. In the 1950s and 60s, blood lead levels of less than 60 micrograms per deciliter were considered acceptable because obvious symptoms of lead poisoning like convulsions did not usually occur above that level. Today the US Centers for Disease Conrol and Prevention (CDC) considers a level of 10 mcg/dl as a threshold of serious effects, especially in children.

    Current information on:

    a. Lead compound toxicity

    b. The International Safety Card for TEL.

    c. The Material Safety Data Sheet for TEL

    d. New data as of May 1, 2001 suggests that even 10 micrograms/liter of lead is too high. Children have show lower IQ scores even at levels under the national standard says Dr. Bruce Lanphear.

    At very high levels of lead exposure, which are now rare in the U.S., lead poisoning can cause mental retardation, coma, convulsions, and death. More common are cases where children are poisoned through chronic, low-level exposure. This can cause reduced IQ and attention span, hyperactivity, impaired growth, reading and learning disabilities, hearing loss, insomnia, and a range of other health behavioral effects. High lead levels have been associated with juvenile delinquency.

    This page titled 4: Tetraethyllead - Toxicity is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by ChemCases.

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