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8: Tetraethyllead - Alice Hamilton

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    One public health scientist, Alice Hamilton (1869-1970) of Harvard University, was particularly dismayed by the decision to allow leaded gasoline back on the market in 1926.

    Alice Hamilton

    Hamilton was one of the most important researchers and advocates for safe working conditions in the hazardous trades. She was an M.D. who had done post-doctoral work at the Universities of Munich and Leipzig in Germany, at the Pasteur Institute in Paris, and at John Hopkins University in the U.S. Her interest in what was called "occupational disease" was sparked by her years working with social activist Jane Addams at Chicago's Hull House, a settlement house in the middle of Chicago's working class slums where social activists lived and worked for progressive causes. Hamilton was to become the acknowledged national expert on lead toxicology, the first woman on the Harvard University faculty and a key figure in the Ethyl controversy.

    Statue of Dr. Alice Hamilton at the Alice Hamilton Ocuupational Health Center in Ft. Wayne, IN. Used with permission

    In 1910, the labor department of the state of Illinois hired her to look into the question of workers' compensation claims from the lead industry trades. Hamilton found appalling conditions and 578 cases of outright lead poisoning, some of which were quite severe, or as Hamilton put it, “equal to those described by French authorities of the early 19th century.”[i] Shocked that Illinois was a century behind Europe, the legislature quickly passed a law requiring ventilation and other safety standards for workers. The Illinois study brought Hamilton to the attention of the U.S. Department of Labor, where she worked from 1910 to 1919 as a special investigator of industrial poisons. She was then invited to join the faculty at Harvard University, and was the first woman to do so. This was not out of egalitarian academic impulse but simply because she was by far the best occupational toxicologist in America, according to biographer Barbara Sicherman.[ii]Hamilton worked with notable tact to popularize the views of social reformers among labor leaders, fellow physicians and industrialists.[iii] In a speech to the superintendents of the National Lead Company, she praised their efforts to safeguard worker health while at the same time noting that their factories were “so dangerous ... that they would be closed by law in any European country.”[iv]

    In 1920, she managed to obtain funding from the American Institute of Lead Manufacturers to study lead metabolism in the human body at Harvard. The study found that lead did accumulate in the bones and tissues of people who were exposed to it, and was not quickly or fully metabolized and excreted. As a practical result, lead manufacturers were disappointed in their attempts to evade workers compensation claims and civil damage suits.[v] A few years later, when General Motors began to put lead into gasoline, Hamilton and others -- including Surgeon General Hugh Cumming -- felt that this study had already laid the key scientific issue to rest. With the cumulative nature of the poison, no one could reasonably advocate the sure, slow public poison from the use of lead in gasoline.[vi]

    1. [i] Ibid., p. 581.
    2. [ii] Barbara Sicherman, Alice Hamilton: A Life in Letters (Cambridge, Mass., Harvard University Press, 1984),
    3. [iii] Ibid., p. 33.
    4. [iv] Ibid., p. 35.
    5. [v] Ibid, p. 238.
    6. [vi] Alice Hamilton, Paul Reznikoff and Grace Burnham, “Tetra Ethyl Lead,” Journal of the American Medical Association, May 16, 1925, pp. 1481-1486.

    Lead Poisoning - An Ancient Problem

    Hamilton knew that, unlike many modern environmental problems, lead presented dangers that had been well appreciated from antiquity. It had been well known as a poison in the Egyptian empire. It was linked to the fall of Rome since at least 1909, but it was commonly suspected since at least the mid-19th century. In 1857, Scientific American noted:

    It is remarkable that this metal (lead), when dissolved in an acid, has the property of imparting a saccharine taste to the fluid. Thus the common acetate of lead is always called ‘sugar of lead.’ It was perhaps on this account that the Greeks and Romans used sheet lead to neutralize the acidity of bad wine -- a practice which now is happily not in use since it has been found that all combinations of lead are decidedly poisonous.

    Along with wine, other sources of lead poisoning in ancient Rome included piping, cookware, cups and plates. But the use of grape sweeteners made in lead vessels probably caused the most damage. Since the Romans did not have sugar, they frequently boiled down grape pulp (or “must”) and used large amounts as a condiment to sweeten their food. They called the pulp “sapa” or “difrutum.” According to lead historian and toxicologist Jerome Niragu: “One teaspoonful of sapa per day could cause chronic lead poisoning, and countless Romans would have consumed more than this dosage from their foods and drinks. ... The Roman fondness for sweet and sour flavors is well known, and the cooks made common use of the cheap ... sapa in their sauces and seasonings to assuage the appetites of their patrons.” Thus, the Romans deliberately consumed large quantities of lead.

    The problem was not simply a few lead pipes in the aquaduct. The sterility and high infant mortality rates experienced by the ruling class during the Empire period, as well as reports of rapid increase of cases of gout where the symptoms directly mirror chronic lead poisoning, were probably results of eating foods sweetened with "sugar" of lead.[iv]

    During the Middle Ages, sceptics who did not believe in “spirits” were frequently referred to the lead mines to see for themselves the way the miners behaved. Early works on tradesmen's diseases usually note, as did Bernardo Ramazzini in 1700, that: "The skin [of lead workers] is apt to bear the same color of the metal ... Demons and ghosts are often found to disturb the miners." For over two millennia, overexposure to lead was known to cause hallucinations and severe mental problems.

    Perhaps the first early modern concern about lead poisoning as a public health problem is documented in the 18th century, when a British physician named George Baker became curious about the “Devonshire colic.” Each autumn, it seemed, there was an infestation of colic that tended to be more severe with the age of the patient. In 1767, Baker examined conditions in Devonshire and traced the colic back to apple cider made by presses lined with lead. He also noted that no similar colic attended the apple harvest in the cider drinking counties of Hereford, Gloucester and Worcester. The presses there had wooden sides without the lead linings. Baker’s paper to the Royal College of Physicians also showed that Devonshire cider itself contained lead. Rather than the praise that might have been expected, Baker was condemned by the clergy, by mill owners and even by fellow doctors.

    Benjamin Franklin was also concerned about lead poisoning. In 1724, when Franklin worked as printer’s apprentice, he observed that the practice of heating lead type while cleaning off ink seemed connected to what was called “the dangles,” an extremely debilitating paralysis of the hands that “dangled” from the wrists for the rest of the worker's life. In 1745, Franklin also published a paper on the “dry gripes,” or stomach cramps -- an epidemic that plagued America that he traced to drinking rum distilled in vessels with lead coils and other parts.

    Franklin and Baker corresponded on scientific matters, and in 1768, Baker said his suspicions that lead might be cause of Devonshire colic “had been greatly confirmed by the authority of Dr. Franklin of Philadelphia.” Also around that time, Franklin obtained a list of patients in La Charite Hospital in Paris who had been hospitalized for symptoms that would today be diagnosed as lead poisoning and showed that the patients were involved in occupations that exposed them to lead.[vii] In 1786, he wrote a long letter to a friend following a conversation on the effects of lead. He concluded: “The Opinion of the mischievous Effect from Lead is at least above Sixty Years old, and you will observe with Concern how long a useful Truth may be known and exist before it is generally receiv’d and practic’d on.”

    In the United States at the turn of the 20th century, concerns about worker health seemed to carry a flavor of “sentimentality if not socialism.” Problems like paralysis of the hands among workers in the lead trade were usually attributed to drinking or to a wife's cooking.[ix] It was difficult even to understand the scope of the problem -- no law forced industries to admit researchers to conduct their studies. Many did so only after a considerable amount of persuasion and assurances that the results of a study would not be reported individually, but rather about an industry in general.


    • [i] R. Kobert, In Beitrage aus der Geschichte der Chemie, ed., P. Diergart, pp. 103-119; 1909.; also see S. Gilfillan, "Roman Culture and Dysgenic Lead Poisoning," Mankind Quarterly, 5, 3-20, Jan-Mar, 1965. // J. Occup. Med., 7:53-60. Both citations from Nriagu, Lead and Lead Poisoning, p. 323.
    • [ii] "Sugar of Lead," Scientific American, Aug. 29, 1857, p. 403.
    • [iii] Nriagu, Lead and Lead Poisoning, p. 332.
    • [iv] Niragu also notes that studies of Roman bones show from two to five parts per million of lead, with increasing amounts in bones of people who died at an older age. Pre-technical cultures which did not use lead, such as the Inca of Peru, show a small fraction of this amount of lead exposure at all ages. Moreover, the bimodal distribution of high lead content in unclassified Roman bones --which has been used to argue against the theory of lead as a factor in the fall of the Roman empire -- may acurately reflect Roman social structure, with the aristocratic group (high lead) able to afford plenty of lead sweetened wine and “sapa” and the lower class unable to afford it.
    • [v] Bernardo Ramazzini, "A Treatise on the Diseases of Tradesmen," circa 1700, cited in an unpublished paper by Lewis R. Thompson, "Knowledge of Industrial Hygiene in the Early Days of History," National Institutes of Health, RG 443 Box 195, National Archives, Washington, D.C.
    • [vi] Marjorie Smith, “Lead in History,” eds. Richard Lansdown and William Yule, Lead Toxicity: History and Environmental Impact, (Baltimore, Md.: Johns Hopkins University Press, 1986) p. 20.
    • [vii] Ibid.
    • [viii] Ibid. p. 21. Also see C.P McCord, “Lead and Lead Poisoning in Early America: Benjamin Franklin and Lead Poisoning,” Ind. Med. Surg. 22, 393-9, cited in Smith, "Lead in History," p. 21.
    • [ix] Alice Hamilton, “Nineteen Years in the Dangerous Trades,” Harpers, Oct 1929, pp. 580-591. This is not quite so far fetched as it might seem -- lead poisoning can come from improperly distilled spirits or from kitchen pots and pans made of lead. However, the problems of workers in the lead trade were often casually dismissed with these remote possibilities.

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