This may be a bit far afield for the Trash Blog, but it’s an interesting story and it concerns a waste product, so here we go:
Using tetraethyl lead as an additive in gasoline was the discovery of a General Motors employee named Thomas Midgley Jr., who’s other inventions include using chlorofluorocarbons (CFCs) as refrigerants and the harness contraption that accidentally strangled him at the age of 55. By all accounts he was brilliant.
Prior to tetraethyl lead additives, gasoline had a tendancy to create engine knock (the premature ignition of fuel). Midgley discovered that tetraethyl lead was the perfect gasoline additive because it made engines run smoothly and was dirt cheap. Unfortunately, as was known at the time, tetraethyl lead is toxic.
In 1922 the U.S. Surgeon General asked the chairman of the board of DuPont (with whom General Motors had contracted to supply tetraethyl lead) if tetraethyl lead was safe. Midgley responded for DuPont that although he didn’t have any actual expiremental data, “the average street will probably be so free from lead that it will be impossible to detect it or its absorption.” In addition to being a genius, he was also an optimist.
Leaded gasoline went on sale in 1923. At first, the biggest issues were on the manufacturing side: in 1924 five workers died in the production of tetraethyl lead. Although their symptoms included those typical of lead poisoning (muscle spasms, writhing, delusions, and violent behavior) a manager listed the explanation of their deaths as: “These men probably went insanse becasue they worked too hard.”
At a press conference at the offices of the Standard Oil Company, Midgley demonstrated that tetraethyl lead was harmless in small doses by rubbing some on his hands. The same day, the New York City Board of Health banned ethyl gasoline. Several other cities were quick to follow suit. The U.S. Bureau of Mines investigated the effects of leaded gasoline exhaust by exposing over 100 types of animals for 3 to 6 hours every day for eight months. The animals did not drop dead, and the Bureau of Mines concluded “The danger of sufficient lead accumulation in the streets…was seemingly remote.”
Many scientists were not convinced: “It seems more likely 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 from a Yale professor of Physiology named Yandell Henderson in 1925. The dean the Harvard School of Public Health called the Bureau of Mines report “half-baked.” Another Harvard professor said that the backers of leaded gasoline were “nothing but murderers.”
Senior executives at Standard Oil called tetraethyl lead “a gift from God.” Throughout the next fifty years the industry continued to claim that leaded gasoline didn’t add much to atmospheric levels of lead, that lead in the air didn’t migrate into human blood, and that low levels of lead in human blood were not toxic, but natural.
It took more than forty years before the U.S. government began to regulate leaded gasoline out of the country. The lead content of gasoline decreased by 99.8% from 1976 to 1990 and the Deparment of Health and Human Services found a 78% drop in human blood-lead levels during the same period. The current U.S. medical threshold for ‘safe’ blood-lead levels is below 10 micrograms per deciliter of blood. Blood levels were higher than this in nearly 78% of children between 1 and 5 years old between 1976 and 1980. The percentage dropped to 4.4 between 1991 and 1994. The EPA put a full ban on leaded gasoline for highway vehicles in 1995.
Sadly, I don’t find it shocking the knowledge of the toxicity of leaded gasoline was known (at least surmised) as early as 1925. Slow poisoning is something we seem very happy to accept in return for convenience or profit.