Welcome to Stuff You Missed in History Class, a production of I Heart Radio. Hello, and welcome to the podcast. I'm Tracy V. Wilson and I'm Holly Fry. I recently learned that the same person developed both leaded gasoline and free on, and those are two substances that are basically banned around the world now because they are both very bad for the environment and for public health. So when I heard this tidbit of information, of course, I thought, holy crap, that guy's definitely getting an episode. And then I didn't write it down. Happens, and I have to write things down, So then I got to rediscover that information a couple of weeks later and write it down that time. That person's name was Thomas Midgley Jr. And when he died, the destructive effects of leaded gasoline were not fully known. They were somewhat known, and we're going to get to that. The destructive effects of clorofluoro carbons, which free on is one of, they weren't known at all yet. So what we're gonna do today is we're gonna walk through Thomas Midgley Junior's biography and then we're gonna double back to take a closer look at those those two most notorious inventions of his and how they both came to be taken off the market. Heads up if you are squeamish about eye injuries, there is one in here that you might want to fast forward through. We'll give a heads up when we get to that. It was too weird and also to me too illustrative of the way his mind worked that I didn't want to just leave it out. Also, Midgeley's death may have been by suicide, and we're gonna be talking about that regardless though of whether his death was intentional or not. I also found the details of how it happened to be pretty upsetting. So this generally an upsetting for a variety of reasons. Yeah, Yeah, it's upsetting from multiple directions, for sure. Thomas Midley Jr. Was born on eight eighty nine in Beaver Falls, Pennsylvania, to Thomas Midley, Senior and Hattie Emerson Midgley. Thomas Sr. Had immigrated to the United States from England and spent most of his career working in the bicycle, automotive, and rubber industries, developing and improving on things like tires with removable Rims. When Thomas Jr. Was young, the family moved to Trenton, New Jersey, and then to Columbus, Ohio. He spent a lot of his life in the Columbus area. According to a biographical address about him that was delivered by his colleague, Charles Kettering, which may have actually been written by another colleague, Thomas Boyd Midgley's inventiveness showed itself really early on. He played baseball along with other sports, and when the spit ball started becoming more popular, he started trying to figure out the best possible substance to put on the ball. He eventually landed on an extract from the inner bark of the slippery Elm Tree Major League Baseball band the spitball in nine. So, in addition to getting an early start on inventing, Thomas also would at an early start with developing things that would then go on to be banned. While attending Bets Academy in Stamford, Connecticut, Thomas took courses in chemistry and really came to love the Periodic Table of Elements during his career as a researcher. He carried a copy of it with him all the time. After graduating from BETS, he went on to Cornell University, where he got a Master of Engineering in nineteen o eight and a pH d in mechanical engineering in nineteen eleven. On August three of that year, he married Carrie M. Reynolds, and they eventually had two children, Jane and Thomas. Although Midgley did his most famous work as a chemist, he started out in a job that was more in line with his engineering degrees. He was working as a draftsman and an engineer at National Cash Register Company, or n c R. After he'd been at NCR for about a year, his father asked him to come work at his tire factory. So Thomas Jr. Did and while he was working at this factory, he started to become more interested in cars. He also kept inventing things, including a hydrometer to check whether there was enough alcohol, and a car's radiator fluid to keep it from freezing up in the wintertime. So he used two balls, each with a different specific gravity, and if the anti freeze mix was right, one of these balls would sink and the other of them would float. When I read this, I was like, oh yeah, because that's the kind of thing that my dad used to show me how to check the radiator fluid when I was a kid. Despite Thomas Jr's help, Thomas Senior's tire factory eventually closed, so Thomas Jr. Needed a new job. While working at NCR, he had become familiar with the work of Charles Kettering. Kettering had already left NCR by the time Midgley started there, but he had been the head of the research division and was credited with more than twenty of NCRS patents. After leaving NCR, Kettering had helped found Dayton Engineering Laboratories Company, or Delco, and that's where Midgley decided he wanted to work. He was hired there in nineteen sixteen and his first project was another hydrometer, this one built into a battery to show how much charge was left. After that, Midgley was asked to work on a solution for engine knock. We're not going to get into the finer points of what's happening inside various types of internal combustion engines, but basically what was supposed to happen was that a spark from the spark plug would ignite the fuel in the cylinder, and then that fuel would effectively burn all at once, but if some of the fuel ignited at the wrong time, not when that spark was sparking, it would cause an unwanted pressure spike inside the cylinder, and this caused a distinctive, very noisy knocking or pinging. It was also inefficient, and it could cause the engine to lose power. It could damage the engine over time. It was not great for engines. At first, Midley proposed dying the fuel red, thinking that would cause it to absorb more heat and evaporate faster, reducing the potential for knock. He had trouble finding a red pigment that would work for this purpose, so his first attempt was with iodine, which made the fuel more of a brownish black, and that did reduce the knock, but it also would have been too expensive for widespread use. When he found other colorance he thought might work, they didn't. It became clear that the iodine itself, not the color of the fuel, was what had reduced the knock. But then the United States became involved in World War One and Midgley had to take a break from this project focus on wartime stuff. During the war, he tried to find a more efficient and powerful air draft fuel, and he eventually landed on a mix that was about seventy percent cyclohexane and benzene. The war ended before this could be put into use, which is probably good because benzine causes cancer. Mentley also worked on an aerial torpedo that similarly wasn't used during the war because it wasn't ready in time. During this period, Mentally dealt with an eye injury and if I stuff squats you out, this would be a good time to skip ahead about a minute. In fifteen seconds, there was a safety plug on a hydrogen tank made of a soft alloy of tin, bismuth, and lead. This plug burst and tiny pieces of it became embedded in Midsley's right cornea. A doctor removed the biggest pieces, but his eye was peppered with flex that were just too small to manually remove. This was really uncomfortable, and Middley started to have problems with his other eye in what felt to him like a sympathetic reaction, So with his doctors okay, he tried a treatment that he came up with on his own, which was to use a cup to hold purified mercury against the surface of the eye. Please don't do this at home. He thought the alloy in his eye would amalgamate with the mercury in the cup, which it did. He was able to remove all the debris from his eye with repeated treatments over the course of about two weeks. Mercury is also toxic, but most harmful exposures are through ingestion or inhalation. Even with that in mind, this just seems no, yeah like that. I'm not a particularly squeamish about I stuff, but that crosses a line for me. No, don't don't do that. Please don't do that. So once the war was over, Midley went back to working on the engine knock problem. After various attempts and failures, he started systematically working his way through the periodic table, trying one element after another. He later described this as a fox hunt. On December third, ninety one, while working as vice president of General Motors Research Laboratories in Dayton, Ohio, Mentally tried tetra ethyl lead. That's a compound that was first developed by German chemist Carl Jacoblog in eighteen fifty three. Mentally discovered that three cubic centimeters of tetrathi lead per gallon of fuel would eliminate engine not completely, but it also caused lead oxide deposits to form in the engine. He then found that adding ethylene bromide to the mix caused all the lead to be emitted from the engine as exhaust, preventing the build up problem. But that presented its own issue, which was getting enough broming. Midjeley is credited with solving that problem as well figuring out a viable way to extract bromine from seawater, where it's present in tiny concentrations, as in sixty five parts per million. This idea did not come out of thin air. Carl Jacob Blowing and French chemist and and Jerome Ballard had each discovered the element bromine around eighteen. Lowig had found it in water from a salt spring, and Billard had to use sea water. With a few other tweaks to the formula, the resulting fuel was marketed as ethel gasoline, and it was first sold to consumers in nine We're going to get back into all of that in more detail later. Midgeley's next problem to solve was refrigerant gas. At the time, a lot of refrigerants were toxic. They included things like ammonia and sulfur dioxide, so refrigerant leaks could be lethal, and in the nineteen twenties air conditioning was becoming more popular. We did a podcast on this back in so there was a lot of demand for a safer alternative. Mint Ley again went back to the periodic table, and this time he focused on fluorine, specifically dichloro difluoro methane. This may not have been the first chlorofluora carbon ever made, or the first fluorine based pound researched as a refrigerant, but it was the first to be widely used and marketed, in this case under the name free On. We will also be getting back to free On again later in this episode as well. In nineteen forty, Midgeley contracted polio. Afterward, his body was partly paralyzed. He started using a wheelchair. From nineteen forty to nineteen forty four, he served as director and vice president of the Ohio State University Research Foundation, and during World War Two he served on the National Research Defense Committee and the National Inventors Council. He did a lot of work with rubber during World War Two, including finding vulcanization methods that could help the country deal with a short supply of rubber. Midgley died unexpectedly at his home in Worthington, Ohio, in nineteen forty four, at the age of fifty five. He had made a lift using rope bars and a trapeeze to help him move from his bed to his wheelchair and back. On November second of that year, he was found entangled in it, strangled by the rope. People who knew him seemed to have been divided over whether they thought this was an accident or intentional. His death certificate lists his cause of death as suicide, and after an autopsy, Franklin County Coroner John B. Gravis came to the same conclusion. During his lifetime and after his death, Thomas Midgley, Jr. Was a deeply respected researcher and chemist. He received multiple awards from the American Chemical Society and the Society of Chemical Industry, along with the Franklin Institute's Longstreath Metal and various honorary doctorates. He was a member of the National Academy of Sciences, the American Association for the Advancement of Science, the American Chemical Society, the American Institute of Chemical Engineers, the Society of Automotive Engineers, and the American Society for Testing Materials. And he held a hundred and seventeen patents. And today we know that his two most famous inventions were destructive to the environment and to human health. Ethel gasoline had also come to market in spite of serious concerns about its safety, and we will be talking about that after we pause for a sponsor break. As we said at the top of the show, today leaded gasoline is banned around the world, although it still does have a couple of limited uses, including in some types of aviation fuel. But letted fuel is no longer sold to people just gassing up their cars and trucks, at least not legally. Most new cars cannot use it. The end of leaded gasoline is astonishingly recent, though. Algeria is the last nation to use up the last of its leaded gas, and that happened in July of one the United The Nation's issued a statement that the global phase out of leaded gas was finally finished on August of that year, so this episode is coming out only a year later. The global move away from leaded gasoline took decades. Japan was the first nation to ban it, that was in eight In the US, the Environmental Protection Agency mandated leaded gasoline be phased out in nineteen seventy three, but it didn't ban the use of leaded fuel in on road vehicles until A lot of discussion during that whole process, starting in the eighties and nineties made it sound like we had only just figured out that leaded gasoline was hazardous. That was not true. The reason that leaded gasoline was first marketed as ethel gasoline was that everybody knew that lead was dangerous. Yes, let does have some very important uses, including things like radiation shielding, but okay. Nections between lead exposure and physical and mental health problems go back thousands of years. They were incredibly well documented in medical literature by the nineteenth century. We just had our episode on Alice Hamilton's, who was one of the founders of the field of occupational health as a Saturday classic, and her groundbreaking work on the hazards of lead exposure in the workplace started a decade before Thomas Midley Jr. Tried putting tetra ethyl lead in gasoline. Tetra ethyl lead was also even more hazardous than a lot of other lead compounds because it could be inhaled. Midgley and other people connected to this research were aware of this. Ethel Gasoline Corporation was founded in nineteen twenty three, bringing together General Motors, which owned the patent on tetra ethyl lead as a fuel additive standard oil of New Jersey, and DuPont, which ran the manufacturing operation. A year later, Pierre DuPont wrote a letter to his brother Irna in which he described tetrath a lead as quote a colorless liquid of Swedish odor, very poisonous if absorbed through the skin, resulting in lead poisoning almost immediately. Charles Kettering described Midley's work with Ethyl Gasoline Corporation as being focused on quote overcoming the prejudice against the new product, which arose from the fear that the use of leading gasoline would poison people. Yet, Midley had to take a month off work in early because he had developed acute lead poisoning, and three of his co workers reported symptoms of lead poisoning as well. Beyond that, Midjeley and Kettering received multiple letters from researchers at prominent universities and institutions, including Harvard and Yale, warning them of the potential dangers of using lead in gasoline. As one example, Dr Eric Krauss at the Institute of Technology and Potsdam, Germany had worked extensively with tetrathel lead. He had this to say, quote the compounds seem to possess, even in very reduced doses, the malicious and creeping poisonous effects which are possessed by inorganic lead compounds. They do not produce the typical symptoms of lead poisoning, but a slow weakening and enfeebling of the whole body, which ultimately results in death. Frequently, the effects of poisoning appear only after a long latent period. I have used every possible means of precaution. Nevertheless, I think that I have severely damaged my health. So he wrote this in a letter that was forwarded around a little bit before being forwarded to midj Ley in December of n Despite the well known hazards of lead exposure, General Motors wanted to introduce ethel gasoline to the market as soon as possible, so production started in nine before adequate ventilation and other safety men were installed. At the factories where it was being made, workers mixed and moved tetrath a lead in open buckets, and one worker described people using their bare fingers to check its clarity. At least one worker died in the first month of production, and workers nicknamed the product looney gas because working around it seemed to cause things like confusion, agitation, sleeplessness, and even delirium. Yeah company later claimed this was made up by journalists to defame their product when it had really been coined by the workers having to produce it. The U S Surgeon General requested some testing, and that testing started through the Bureau of Minds also in nine three. The tests were carried out in collaboration with General Motors. They involved exposing various animals to exhaust. The Bureau issued a report in October of n four describing the risk to the public from breathing in this exhaust as negligible. But a scathing response to this report was published in the Journal of the American Medical Association. One of its authors was Alice Hamilton's and it pointed out many flaws in this research, calling it quote inadequate in scope, in technic, and in conclusiveness. Meanwhile, around the same time, the U. S. Army Chemical Warfare Service did six months of experiments with tetrathe lad to see if it was suitable as a chemical warfare agent, and found it to be dangerous. A report from Edgewood arsenal. Called it quote probably the only compound where acute lead poisoning follows absorption through the skin, and describing less than lethal doses having a cumulative effect on test subjects. Also in October of nine, the same month that Bureau of Mine's report came out, seven workers died at a standard oil plant in by Way, New Jersey, and more than thirty the developed symptoms of acute lead poisoning. Some of them developed a lifelong violent psychosis requiring permanent hospitalization. Other deaths and cases of lead poisoning took place at multiple DuPont and GM plants between ninety three and n but the companies involved maintained that these were cases of worker error or production issues that were then corrected, and that improved ventilation and safety procedures would fix the problem at the factories. They also maintained that tetra ethyl lead was safe at the concentrations that the public would encounter. Midgley seemed to genuinely believe this, and at one press conference in nineteen four washed his hands in leaded gasoline as a safety demonstration, even though he had had lead poisoning himself to previous year. Meanwhile, the general public and various officials were outraged and alarmed over what was happening to workers at the fuel fact reas the state of New Jersey, in the cities of New York and Philadelphia all banned the sale of leaded gasoline. Kettering and Midgley were both removed from their leadership roles at the company in April of ninety five, although GM CEO Alfred P. Sloan was quoted as saying that Midgley quote was entirely inexperienced and organization matters kind of implied that this firing was unrelated to the backlash against his invention. He's just a bad administrator, not a good fit. Uh. They still had jobs to the company, they just were not in leadership roles anymore. Right. Just after this, Ethel Gasoline Corporation suspended the sale of leaded gasoline pending a public health review. The U. S. Surgeon General appointed a committee to carry this review out during a conference held on the fuel industry, maintained that tetrath a led was the best and only solution to the knock problem. Of public health experts insisted that it was dangerous and that the industry needed to find another way. During this conference, Alice Hamilton's reportedly called Charles Kettering a murderer. Ultimately, the Surgeon General's Committee reported that quote there are at present no good grounds for prohibiting the use of ethel gasoline with a composition specified as a motor fuel, provided that its distribution and use are controlled by proper regulation. But the committee also noted that this could change with a rise in the number of vehicles on the road and recommended further studies supervised by the Surgeon General to account for these shifts and how much leaded gasoline was actually being used. Those follow up studies didn't happen, though, and according to the Department of Transportation, the number of registered motor vehicles in the United States roughly doubled over the next two decades. Ethel gasoline returned to market on May sixty six. Over that year long pause, the Ethyl Gasoline Corporation and DuPont had made safety changes and ventilation upgrades at their factories. Thanks to strict manufacturing and distribution rules, the following years did not see the kinds of deaths and injuries to workers that had taken place earlier. In the nineteen twenties, leaded gasoline became standard in much of the world. By nine thirty six, it made up of the gasoline sold in the United States. The Surgeon General also approved an increase in the amount of tetrath a lad in gasoline from three million leads per gallont to four in nineteen fifty nine. A few years later, a widespread movement against leaded gasoline started to evolve in the United States and worldwide. This was inspired in part by Rachel Carson's nineteen sixty two Silent Spring and that book's influence on the environmental movement. Another factor was a series of deadly small incidents that had taken place in multiple cities around the world starting around the nineteen thirties. This included the Great London Smog and the Dinora Smog, both of which we have covered on the show before. An increasing body of scientific work suggested that air pollution was a serious threat to people's health. Research and multiple cities also found high levels of lead in the air, with public health research going on at the same time suggesting that lead was harming people. There's actually a whole hypothesis that the increase in atmospheric lead in the middle of the twentieth century contributed to an increase in crime in the United States in the nineteen seventies, and that the ban on leaded fuel then contributed to a drop in crime rates starting in the nineteen nineties. That is very hard to pin down specifically because a lot of other stuff was happening across those same years, But at the same time, it was very obviously clear that inhaling a bunch of lead all the time was causing problems, and it was causing most problems for often the poorest people who were living in really congested parts of cities. It's infuriating. Nations started passing anti pollution and clean air legislation, including things like the Clean Air Act of nineteen seventy in the United States. These laws included things like mandatory reductions in the amount of pollutants in car exhaust. In the US, the specific focus was a reduction in carbon monoxide, nitrogen oxides, and other hydrocarbons, which led to the development of the catalytic converter. The catalytic converter reduced those pollutants in car exhaust, but it also could not be used in a car that was running on leaded gasoline because the lead in the gasoline would destroy the catalysts in the converter. So from the car industry's perspective, that was a much bigger driver in the phase out of leaded gasoline than leads dangers to public health. GM announced that catalytic converters would be installed in all of its new automobiles in nineteen seventy. General Motors and the Standard Oil had already sold Ethel Corporation by that point. That happened in nineteen sixty two. Letted gasoline was gradually phased out and banned around the world over the decades that followed, although there were exceptions. In general, wealthy countries made the switch first, while leaded gasoline continued to be marketed and sold in other parts of the world, with most of the last nations to make the switch being in the Middle East and Africa. The UN Environment Program started a campaign to eliminate leaded gas worldwide in two thousand two, and as we said at the top of the show, that was finally accomplished just last year, as we're recording this in and one last infuriating thing before we move on. Tetra ethel lad wasn't the only anti knock agent being evaluated in the United States in the nineteen twenties. Another was ethyl alcohol or ethanol, which is the most unleaded gasoline today and was actually already in use in some parts of the world while leaded gasoline was being developed. Thomas Midley Jr. And Thomas Boyd looked into ethanol in the nineteen twenties. They knew that in a lot of ways it was superior to tetra ethyl lead that had similar anti knock properties, and since it was made from fermenting sugars or grains, it was renewable. Ethanol can certainly have negative health effects. Ethanol is what's in alcoholic beverages. We know there are risks that come along with that, but as a fuel additive, it is not nearly as toxic as lead. But this was also during the Prohibition era, and although industrial alcohol wasn't prohibited, this still presented some challenges. General motors also had a patent on tetrath a lead as a fuel additive, but not on ethanol, meaning there was a lot more profit potential for the company with leaded gasoline. The petroleum industry was also concerned about the possibility of ethanol overtaking petroleum as a fuel source, so through all the controversy and hearings in the nineteen twenties, fuel companies were insisting that there was no alternative to lead, even though they knew that there was. So let's take a break and maybe go find a pillow to scream into, because that was infuriating. The story of Thomas Midgley Junior's development of dichloro di flora methane or free on and its eventual phasing out is somewhat less infuriating, at least to me than the tucher at the lead saga, because the damaging effects of free on were not known until long after his death, and the response to finding out about how imaging it was was a lot quicker while he was living, free on really did seem like a vastly better option than the toxic or flammable gases that were in use as refrigerants. For example, in nineteen twenty nine, several people died as a direct result of refrigerant leaks, including a cluster of incidents in Chicago. Sometimes this is cited as the reason that Midgley was looking for a better refrigerant, but he actually developed free On in nine. That work was not announced until nineteen thirty, though, so that may be partially to blame for the confusion about why he started working on it. Midgley's actual process for making this discovery is a little bit vague. He was working at GM, which owned frigid Air, and frigid Air was looking for a new refrigerant. Midgley reportedly developed free On as a refrigerant over the span of only three days. He was focused on compounds that included aureene, starting with carbon tetrafluoride. He thought it was promising because if it's boiling point of minus one seven point eight celsius. He also looked at at least one other chlorofluora carbon that was dichloro mono flora methane before focusing on dichloro diflora methane. That chloro diflora methane was marketed as free On twelve. Similarly, to the establishment of Ethel Gasoline Corporation. Kinetic Chemicals was founded to manufacture this substance. That was through a partnership between General Motors and DuPont. Midgley became one of the company's directors. Soon Freon was being widely used in refrigerators and in the first home air conditioners. Again, there's more on that in our History of air Conditioning episode that came out in August of Based on what was known at the time, freon was unquestionably better than other alternatives. It was non flammable, non top toxic, stable, and essentially odorless. Midgley would demonstrated safety by inhaling a big lungful of it and exhaling it to blow out a candle, something that probably would have seriously injured or killed him if he tried it with earlier refrigerants. That doesn't mean it was a great idea. We've already established that he intentionally exposed himself to things to demonstrate their safety when it wasn't necessarily safe. Other chlorofluoro carbons and hydrochlorofluorocarbons, or CFCs and h CFCs followed, along with other applications for them. During World War Two, freon was found to be particularly effective for dispersing insect repellents. Soon, CFCs are being used as propellants in things like hairsprays. At this point, scientists knew the ozone layer existed. Charles Fabri and Enrie Bouisson had measured it for the first time in nineteen sixteen. They and others started studying in and in nineteen fifty six scientists started taking ongoing measurements at the Halley Bay Observatory on Antarctica. The rise of things like commercial air travel and the space Race led to a bigger focus on the ozone layer, as researchers wondered whether emissions from those vehicles would affect the atmosphere. By the nineteen seventies, data from the Halle Bay Observatory and from satellites showed that the ozone layer was being depleted, but it wasn't yet clear why. Then, in nineteen seventy four, Mario Molina and F. Sherwood Roland published a paper in the journal Nature titled Stratospheric sync for chlorofluoro methanes chlorine ADAM catalyzed destruction of ozone. This paper explained that chlorofluoro methanes, which are a type of hydrochlorofluoro carbon destroyed atmospheric ozone. Molina and Roland were awarded the Nobel Prize in Chemistry for this work, along with Paul kritz And, whose work was focused on the ozone depleting ability of nitrogen oxides. Although air and space travel had been seen as potential threats before this point, this research revealed that common household products were a serious problem. CFCs and HCFC's uses propellants in spray bottles, in refrigerators and air conditioning systems, and in plastic foams. These compounds were both inert and volatile, which meant they could be carried high into the atmosphere unchanged. Once they were there, though, UV light broke them down, releasing chlorine into the upper atmosphere, where it acted as a catalyst to break down the ozone layer. Molina and Roland predicted that if CFC use continued at the rate that it was going, eventually the ozone layer would be entirely depleted. The ozone layer helps protect the Earth from UV radiation, and without it, experts predicted sharp increases in things like cataracts and atal skin cancers, as well as damage to crops and ecosystems that are sensitive to UV light. This was caused for alarm, and some places started putting limits on CFC's and h CFC's In the nineteen seventies and early eighties, a conference was also convened in Vienna, Austria, and on March twenty two, twenty nations signed the Vienna Convention for the Protection of the Ozone Layer. This included most of the nations where most of the world CFCs were being produced. This convention set up a framework for nations to work together to try to address this problem. It focused on things like information sharing and research, rather than on taking specific actions to keep the layer from depleting any further. On May one, five, a team led by Joseph Farman at the British Antarctic Survey published another paper in the journal Nature, this one reporting that the ozone layer over Antarctica was already significantly depleted. This depletion was so dramatic that Farming at first thought his instruments were malfunctioning. This heavily depleted area over Antarctica became known as the Whole in the Ozone Layer, but there were other proposed causes for this depletion besides CFCs and h CFCs, and additional research had to be done to confirm what was going on. Then, in the Antarctic Airborne Ozone Expedition took measurements high in the atmosphere which showed that if there was more chlorine monoxide in an area, there was also less ozone. So it was clear that global action was needed to reduce the production and use of ozone depleting substances like CFCs and h CFCs. Building on that framework that had been set up in the Vienna Convention, nations came together again, this time in Montreal. In on September six of that year, forty six countries signed on to the international treaty that came to be known as the Montreal Protocol. Its terms included a phasing out of the production and use of several types of ozone depleting chemicals, setting a target of reducing them to fifty of nine levels by less wealthy countries were allowed a grace period to make the transition, and since then the treaty has been amended to completely ban a range of ozone depleting substances. The Vienna Convention in the Montreal Protocol are the only international treaties that have been signed by every member state of the United Nations. Many ozone depleting substances were completely phased out around the world in the nineteen nineties and early two thousands, and the few that remain are scheduled to be phased out by twenty forty. The ozone layer has already started to recover, and it is estimated that it will be entirely restored by twenty fifty. So when you hear somebody say something like, remember when everybody was freaking out about the ozone layer, and now we never hear a thing about that anymore, kind of implying that it was some kind of manufactured panic, and maybe we can just disregard other alarming reports about things like climate change. The reason we don't hear about it anymore is because the world actually came together to take action to address and fix this problem. Definitively, it can be done. It can especially be done when there are alternatives that exist that are maybe only a little bit more expensive, and you don't have an entire industry is spreading a whole lot of disinformation saying the climate change isn't real? What that's crazy? Hey, do you have a listener? Uh? This listener mail is from Abbey, who sents a note that is titled O MG diarial man and Abby started by saying dearest, just oriens and then the first paragraph of the email has some various personal details, but Abby talks about wanting to be a history major. But because Abby's parents assumed that history majors all became teachers um and did not think that Abby would have the patients to really be a teacher, they discouraged that line of education. But now Abby has become a a an avid listener to the podcast. So now on to the actional actual reason I'm writing. I've been a pharmacist for the last fifteen years, both at the at a retail pharmacy and now as a hospital pharmacist. While I was in school, I discovered a way to meld my love of science and history by studying medical history. My university actually had a History of Pharmacy elective, and it was taught by the most delightful professor ever. Addition to being a PhD in pharmaceutics and a pharmacist, he was also a veteran of World War One. He was a pharmacist in the Battle of the Bulge. I love to hear his stories of pharmacy during the war, especially the way the army recycled penicillin to share with the French civilians. This professor introduced me to the wonders of medical history items available on eBay, and gave me my first antique medical books. Since then, my collection has grown to fill several bookshelves and photos covering the walls of my office. When you mentioned the diarial man and the hypertension episode, I literally jumped up from my sewing machine. I'm a nerdy quilter too, and went directly to the internet. I'm proud to say I found one, and he's on his way to me now. Although drug companies have stopped making and sharing chatzky in the last ten or fifteen years, I always loved when we would get a new set of fancy drug pens, notepads or counting trays. My favorite item I've collected was a pen for the little blue pill that folded in half, and when you needed to use it, you pushed a button on the end and it very comically flipped open in a rather slow and hilarious manner. I'm sure that someone on the Fiser marketing team was very proud of that one. I'm not sure if I should thank you or not for educating me on the possibility to expand my collection to include drug rep paraphnalia or not, but I'm now on the hunt for other antique findes like dire ol Man. I also want to thank you for the rabies episode earlier this year. Thank you for sharing the stories of why we pretty much treat anyone who comes in contact with bats in the US. I made sure to share the information with the pharmacy staff because my hospital has several emergency room visits every year for bat exposures and we almost always end up administering rabies vaccines and immune globulin shots. It was always crazy to my fellow pharmacists and me about why so many people go to the e er when they just have a bat in their house or they accidentally touched a dead bat outside. We often thought people were being overly dramatic, especially when we had a family of eight come in and all needed treatment because we had to call all over the state to get enough vaccine. While I can confirm that the rabies series is a lot of vaccinations for of them over fourteen days. The urban legend stories of the need to use giant needles for shots and the bellies false. But it is quite uncomfortable when there is a bite because we have to inject the immune globulin and small amounts all around the bite location. It doss of immune globulin are based on the patient's wait. It can sometimes end up being a lot of pokes. Apologies for such a long email, but I have attached kitty pictures as penance. Uh, these kiddies are adornable. Um, since as we said, Abby is the pharmacist. These are named after antibiotics. Um, there's I'm gonna say this strong moxic flu accin. It's probably right, moxie. And that's a great tabby. Oh no, that's an orange tabby. And then the great tabby is linkomycin or link Um. I love naming naming the kiddies after antibiotics. I think that's great. So number one, I got this email and I love that. Somebody else was like, I'm gonna go get a direal man, and I'm I'm like our email sellers, like, why is everybody's side like what, I love my diarial man Yeah, Holly already got a direl man um. The other thing was I had to go look up and see how the army recycled penicillin. I had an idea in my head of how probably that happened, and that idea was the correct idea. And I'm not going to go into detail about it right now because it's a little gross for more squeamish people. But I realized, even though I was sure we had like a penicillin episode, I don't actually think we do. We have other antibiotic stuff. I'll double check. If we don't have a penicillin episode, we probably should because the oversimplified children's book story of how penicillin was developed is not, as is often the case, not not really cute. It is very cute and not very complete. So thank you again, Abby for this email and for the cat pictures. If you would like to write to us about this or any other podcast or at history podcasts that I Heart radio dot com. If you're going to write to us to say that climate change is not real, just keep that to yourself because that's incorrect. We are on the I Heart Radio app wherever else you like to get your podcasts and we hope you will tune in next time. Kind of scared you away with our climate talk. Stuff you Missed in History Class is a production of I heart Radio. For more podcasts from I heart Radio, visit the i heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.

Welcome to Stuff You Missed in History Class, a production of I Heart Radio. Hello, and welcome to the podcast. I'm Tracy V. Wilson and I'm Holly Fry. I recently learned that the same person developed both leaded gasoline and free on, and those are two substances that are basically banned around the world now because they are both very bad for the environment and for public health. So when I heard this tidbit of information, of course, I thought, holy crap, that guy's definitely getting an episode. And then I didn't write it down. Happens, and I have to write things down, So then I got to rediscover that information a couple of weeks later and write it down that time. That person's name was Thomas Midgley Jr. And when he died, the destructive effects of leaded gasoline were not fully known. They were somewhat known, and we're going to get to that. The destructive effects of clorofluoro carbons, which free on is one of, they weren't known at all yet. So what we're gonna do today is we're gonna walk through Thomas Midgley Junior's biography and then we're gonna double back to take a closer look at those those two most notorious inventions of his and how they both came to be taken off the market. Heads up if you are squeamish about eye injuries, there is one in here that you might want to fast forward through. We'll give a heads up when we get to that. It was too weird and also to me too illustrative of the way his mind worked that I didn't want to just leave it out. Also, Midgeley's death may have been by suicide, and we're gonna be talking about that regardless though of whether his death was intentional or not. I also found the details of how it happened to be pretty upsetting. So this generally an upsetting for a variety of reasons. Yeah, Yeah, it's upsetting from multiple directions, for sure. Thomas Midley Jr. Was born on eight eighty nine in Beaver Falls, Pennsylvania, to Thomas Midley, Senior and Hattie Emerson Midgley. Thomas Sr. Had immigrated to the United States from England and spent most of his career working in the bicycle, automotive, and rubber industries, developing and improving on things like tires with removable Rims. When Thomas Jr. Was young, the family moved to Trenton, New Jersey, and then to Columbus, Ohio. He spent a lot of his life in the Columbus area. According to a biographical address about him that was delivered by his colleague, Charles Kettering, which may have actually been written by another colleague, Thomas Boyd Midgley's inventiveness showed itself really early on. He played baseball along with other sports, and when the spit ball started becoming more popular, he started trying to figure out the best possible substance to put on the ball. He eventually landed on an extract from the inner bark of the slippery Elm Tree Major League Baseball band the spitball in nine. So, in addition to getting an early start on inventing, Thomas also would at an early start with developing things that would then go on to be banned. While attending Bets Academy in Stamford, Connecticut, Thomas took courses in chemistry and really came to love the Periodic Table of Elements during his career as a researcher. He carried a copy of it with him all the time. After graduating from BETS, he went on to Cornell University, where he got a Master of Engineering in nineteen o eight and a pH d in mechanical engineering in nineteen eleven. On August three of that year, he married Carrie M. Reynolds, and they eventually had two children, Jane and Thomas. Although Midgley did his most famous work as a chemist, he started out in a job that was more in line with his engineering degrees. He was working as a draftsman and an engineer at National Cash Register Company, or n c R. After he'd been at NCR for about a year, his father asked him to come work at his tire factory. So Thomas Jr. Did and while he was working at this factory, he started to become more interested in cars. He also kept inventing things, including a hydrometer to check whether there was enough alcohol, and a car's radiator fluid to keep it from freezing up in the wintertime. So he used two balls, each with a different specific gravity, and if the anti freeze mix was right, one of these balls would sink and the other of them would float. When I read this, I was like, oh yeah, because that's the kind of thing that my dad used to show me how to check the radiator fluid when I was a kid. Despite Thomas Jr's help, Thomas Senior's tire factory eventually closed, so Thomas Jr. Needed a new job. While working at NCR, he had become familiar with the work of Charles Kettering. Kettering had already left NCR by the time Midgley started there, but he had been the head of the research division and was credited with more than twenty of NCRS patents. After leaving NCR, Kettering had helped found Dayton Engineering Laboratories Company, or Delco, and that's where Midgley decided he wanted to work. He was hired there in nineteen sixteen and his first project was another hydrometer, this one built into a battery to show how much charge was left. After that, Midgley was asked to work on a solution for engine knock. We're not going to get into the finer points of what's happening inside various types of internal combustion engines, but basically what was supposed to happen was that a spark from the spark plug would ignite the fuel in the cylinder, and then that fuel would effectively burn all at once, but if some of the fuel ignited at the wrong time, not when that spark was sparking, it would cause an unwanted pressure spike inside the cylinder, and this caused a distinctive, very noisy knocking or pinging. It was also inefficient, and it could cause the engine to lose power. It could damage the engine over time. It was not great for engines. At first, Midley proposed dying the fuel red, thinking that would cause it to absorb more heat and evaporate faster, reducing the potential for knock. He had trouble finding a red pigment that would work for this purpose, so his first attempt was with iodine, which made the fuel more of a brownish black, and that did reduce the knock, but it also would have been too expensive for widespread use. When he found other colorance he thought might work, they didn't. It became clear that the iodine itself, not the color of the fuel, was what had reduced the knock. But then the United States became involved in World War One and Midgley had to take a break from this project focus on wartime stuff. During the war, he tried to find a more efficient and powerful air draft fuel, and he eventually landed on a mix that was about seventy percent cyclohexane and benzene. The war ended before this could be put into use, which is probably good because benzine causes cancer. Mentley also worked on an aerial torpedo that similarly wasn't used during the war because it wasn't ready in time. During this period, Mentally dealt with an eye injury and if I stuff squats you out, this would be a good time to skip ahead about a minute. In fifteen seconds, there was a safety plug on a hydrogen tank made of a soft alloy of tin, bismuth, and lead. This plug burst and tiny pieces of it became embedded in Midsley's right cornea. A doctor removed the biggest pieces, but his eye was peppered with flex that were just too small to manually remove. This was really uncomfortable, and Middley started to have problems with his other eye in what felt to him like a sympathetic reaction, So with his doctors okay, he tried a treatment that he came up with on his own, which was to use a cup to hold purified mercury against the surface of the eye. Please don't do this at home. He thought the alloy in his eye would amalgamate with the mercury in the cup, which it did. He was able to remove all the debris from his eye with repeated treatments over the course of about two weeks. Mercury is also toxic, but most harmful exposures are through ingestion or inhalation. Even with that in mind, this just seems no, yeah like that. I'm not a particularly squeamish about I stuff, but that crosses a line for me. No, don't don't do that. Please don't do that. So once the war was over, Midley went back to working on the engine knock problem. After various attempts and failures, he started systematically working his way through the periodic table, trying one element after another. He later described this as a fox hunt. On December third, ninety one, while working as vice president of General Motors Research Laboratories in Dayton, Ohio, Mentally tried tetra ethyl lead. That's a compound that was first developed by German chemist Carl Jacoblog in eighteen fifty three. Mentally discovered that three cubic centimeters of tetrathi lead per gallon of fuel would eliminate engine not completely, but it also caused lead oxide deposits to form in the engine. He then found that adding ethylene bromide to the mix caused all the lead to be emitted from the engine as exhaust, preventing the build up problem. But that presented its own issue, which was getting enough broming. Midjeley is credited with solving that problem as well figuring out a viable way to extract bromine from seawater, where it's present in tiny concentrations, as in sixty five parts per million. This idea did not come out of thin air. Carl Jacob Blowing and French chemist and and Jerome Ballard had each discovered the element bromine around eighteen. Lowig had found it in water from a salt spring, and Billard had to use sea water. With a few other tweaks to the formula, the resulting fuel was marketed as ethel gasoline, and it was first sold to consumers in nine We're going to get back into all of that in more detail later. Midgeley's next problem to solve was refrigerant gas. At the time, a lot of refrigerants were toxic. They included things like ammonia and sulfur dioxide, so refrigerant leaks could be lethal, and in the nineteen twenties air conditioning was becoming more popular. We did a podcast on this back in so there was a lot of demand for a safer alternative. Mint Ley again went back to the periodic table, and this time he focused on fluorine, specifically dichloro difluoro methane. This may not have been the first chlorofluora carbon ever made, or the first fluorine based pound researched as a refrigerant, but it was the first to be widely used and marketed, in this case under the name free On. We will also be getting back to free On again later in this episode as well. In nineteen forty, Midgeley contracted polio. Afterward, his body was partly paralyzed. He started using a wheelchair. From nineteen forty to nineteen forty four, he served as director and vice president of the Ohio State University Research Foundation, and during World War Two he served on the National Research Defense Committee and the National Inventors Council. He did a lot of work with rubber during World War Two, including finding vulcanization methods that could help the country deal with a short supply of rubber. Midgley died unexpectedly at his home in Worthington, Ohio, in nineteen forty four, at the age of fifty five. He had made a lift using rope bars and a trapeeze to help him move from his bed to his wheelchair and back. On November second of that year, he was found entangled in it, strangled by the rope. People who knew him seemed to have been divided over whether they thought this was an accident or intentional. His death certificate lists his cause of death as suicide, and after an autopsy, Franklin County Coroner John B. Gravis came to the same conclusion. During his lifetime and after his death, Thomas Midgley, Jr. Was a deeply respected researcher and chemist. He received multiple awards from the American Chemical Society and the Society of Chemical Industry, along with the Franklin Institute's Longstreath Metal and various honorary doctorates. He was a member of the National Academy of Sciences, the American Association for the Advancement of Science, the American Chemical Society, the American Institute of Chemical Engineers, the Society of Automotive Engineers, and the American Society for Testing Materials. And he held a hundred and seventeen patents. And today we know that his two most famous inventions were destructive to the environment and to human health. Ethel gasoline had also come to market in spite of serious concerns about its safety, and we will be talking about that after we pause for a sponsor break. As we said at the top of the show, today leaded gasoline is banned around the world, although it still does have a couple of limited uses, including in some types of aviation fuel. But letted fuel is no longer sold to people just gassing up their cars and trucks, at least not legally. Most new cars cannot use it. The end of leaded gasoline is astonishingly recent, though. Algeria is the last nation to use up the last of its leaded gas, and that happened in July of one the United The Nation's issued a statement that the global phase out of leaded gas was finally finished on August of that year, so this episode is coming out only a year later. The global move away from leaded gasoline took decades. Japan was the first nation to ban it, that was in eight In the US, the Environmental Protection Agency mandated leaded gasoline be phased out in nineteen seventy three, but it didn't ban the use of leaded fuel in on road vehicles until A lot of discussion during that whole process, starting in the eighties and nineties made it sound like we had only just figured out that leaded gasoline was hazardous. That was not true. The reason that leaded gasoline was first marketed as ethel gasoline was that everybody knew that lead was dangerous. Yes, let does have some very important uses, including things like radiation shielding, but okay. Nections between lead exposure and physical and mental health problems go back thousands of years. They were incredibly well documented in medical literature by the nineteenth century. We just had our episode on Alice Hamilton's, who was one of the founders of the field of occupational health as a Saturday classic, and her groundbreaking work on the hazards of lead exposure in the workplace started a decade before Thomas Midley Jr. Tried putting tetra ethyl lead in gasoline. Tetra ethyl lead was also even more hazardous than a lot of other lead compounds because it could be inhaled. Midgley and other people connected to this research were aware of this. Ethel Gasoline Corporation was founded in nineteen twenty three, bringing together General Motors, which owned the patent on tetra ethyl lead as a fuel additive standard oil of New Jersey, and DuPont, which ran the manufacturing operation. A year later, Pierre DuPont wrote a letter to his brother Irna in which he described tetrath a lead as quote a colorless liquid of Swedish odor, very poisonous if absorbed through the skin, resulting in lead poisoning almost immediately. Charles Kettering described Midley's work with Ethyl Gasoline Corporation as being focused on quote overcoming the prejudice against the new product, which arose from the fear that the use of leading gasoline would poison people. Yet, Midley had to take a month off work in early because he had developed acute lead poisoning, and three of his co workers reported symptoms of lead poisoning as well. Beyond that, Midjeley and Kettering received multiple letters from researchers at prominent universities and institutions, including Harvard and Yale, warning them of the potential dangers of using lead in gasoline. As one example, Dr Eric Krauss at the Institute of Technology and Potsdam, Germany had worked extensively with tetrathel lead. He had this to say, quote the compounds seem to possess, even in very reduced doses, the malicious and creeping poisonous effects which are possessed by inorganic lead compounds. They do not produce the typical symptoms of lead poisoning, but a slow weakening and enfeebling of the whole body, which ultimately results in death. Frequently, the effects of poisoning appear only after a long latent period. I have used every possible means of precaution. Nevertheless, I think that I have severely damaged my health. So he wrote this in a letter that was forwarded around a little bit before being forwarded to midj Ley in December of n Despite the well known hazards of lead exposure, General Motors wanted to introduce ethel gasoline to the market as soon as possible, so production started in nine before adequate ventilation and other safety men were installed. At the factories where it was being made, workers mixed and moved tetrath a lead in open buckets, and one worker described people using their bare fingers to check its clarity. At least one worker died in the first month of production, and workers nicknamed the product looney gas because working around it seemed to cause things like confusion, agitation, sleeplessness, and even delirium. Yeah company later claimed this was made up by journalists to defame their product when it had really been coined by the workers having to produce it. The U S Surgeon General requested some testing, and that testing started through the Bureau of Minds also in nine three. The tests were carried out in collaboration with General Motors. They involved exposing various animals to exhaust. The Bureau issued a report in October of n four describing the risk to the public from breathing in this exhaust as negligible. But a scathing response to this report was published in the Journal of the American Medical Association. One of its authors was Alice Hamilton's and it pointed out many flaws in this research, calling it quote inadequate in scope, in technic, and in conclusiveness. Meanwhile, around the same time, the U. S. Army Chemical Warfare Service did six months of experiments with tetrathe lad to see if it was suitable as a chemical warfare agent, and found it to be dangerous. A report from Edgewood arsenal. Called it quote probably the only compound where acute lead poisoning follows absorption through the skin, and describing less than lethal doses having a cumulative effect on test subjects. Also in October of nine, the same month that Bureau of Mine's report came out, seven workers died at a standard oil plant in by Way, New Jersey, and more than thirty the developed symptoms of acute lead poisoning. Some of them developed a lifelong violent psychosis requiring permanent hospitalization. Other deaths and cases of lead poisoning took place at multiple DuPont and GM plants between ninety three and n but the companies involved maintained that these were cases of worker error or production issues that were then corrected, and that improved ventilation and safety procedures would fix the problem at the factories. They also maintained that tetra ethyl lead was safe at the concentrations that the public would encounter. Midgley seemed to genuinely believe this, and at one press conference in nineteen four washed his hands in leaded gasoline as a safety demonstration, even though he had had lead poisoning himself to previous year. Meanwhile, the general public and various officials were outraged and alarmed over what was happening to workers at the fuel fact reas the state of New Jersey, in the cities of New York and Philadelphia all banned the sale of leaded gasoline. Kettering and Midgley were both removed from their leadership roles at the company in April of ninety five, although GM CEO Alfred P. Sloan was quoted as saying that Midgley quote was entirely inexperienced and organization matters kind of implied that this firing was unrelated to the backlash against his invention. He's just a bad administrator, not a good fit. Uh. They still had jobs to the company, they just were not in leadership roles anymore. Right. Just after this, Ethel Gasoline Corporation suspended the sale of leaded gasoline pending a public health review. The U. S. Surgeon General appointed a committee to carry this review out during a conference held on the fuel industry, maintained that tetrath a led was the best and only solution to the knock problem. Of public health experts insisted that it was dangerous and that the industry needed to find another way. During this conference, Alice Hamilton's reportedly called Charles Kettering a murderer. Ultimately, the Surgeon General's Committee reported that quote there are at present no good grounds for prohibiting the use of ethel gasoline with a composition specified as a motor fuel, provided that its distribution and use are controlled by proper regulation. But the committee also noted that this could change with a rise in the number of vehicles on the road and recommended further studies supervised by the Surgeon General to account for these shifts and how much leaded gasoline was actually being used. Those follow up studies didn't happen, though, and according to the Department of Transportation, the number of registered motor vehicles in the United States roughly doubled over the next two decades. Ethel gasoline returned to market on May sixty six. Over that year long pause, the Ethyl Gasoline Corporation and DuPont had made safety changes and ventilation upgrades at their factories. Thanks to strict manufacturing and distribution rules, the following years did not see the kinds of deaths and injuries to workers that had taken place earlier. In the nineteen twenties, leaded gasoline became standard in much of the world. By nine thirty six, it made up of the gasoline sold in the United States. The Surgeon General also approved an increase in the amount of tetrath a lad in gasoline from three million leads per gallont to four in nineteen fifty nine. A few years later, a widespread movement against leaded gasoline started to evolve in the United States and worldwide. This was inspired in part by Rachel Carson's nineteen sixty two Silent Spring and that book's influence on the environmental movement. Another factor was a series of deadly small incidents that had taken place in multiple cities around the world starting around the nineteen thirties. This included the Great London Smog and the Dinora Smog, both of which we have covered on the show before. An increasing body of scientific work suggested that air pollution was a serious threat to people's health. Research and multiple cities also found high levels of lead in the air, with public health research going on at the same time suggesting that lead was harming people. There's actually a whole hypothesis that the increase in atmospheric lead in the middle of the twentieth century contributed to an increase in crime in the United States in the nineteen seventies, and that the ban on leaded fuel then contributed to a drop in crime rates starting in the nineteen nineties. That is very hard to pin down specifically because a lot of other stuff was happening across those same years, But at the same time, it was very obviously clear that inhaling a bunch of lead all the time was causing problems, and it was causing most problems for often the poorest people who were living in really congested parts of cities. It's infuriating. Nations started passing anti pollution and clean air legislation, including things like the Clean Air Act of nineteen seventy in the United States. These laws included things like mandatory reductions in the amount of pollutants in car exhaust. In the US, the specific focus was a reduction in carbon monoxide, nitrogen oxides, and other hydrocarbons, which led to the development of the catalytic converter. The catalytic converter reduced those pollutants in car exhaust, but it also could not be used in a car that was running on leaded gasoline because the lead in the gasoline would destroy the catalysts in the converter. So from the car industry's perspective, that was a much bigger driver in the phase out of leaded gasoline than leads dangers to public health. GM announced that catalytic converters would be installed in all of its new automobiles in nineteen seventy. General Motors and the Standard Oil had already sold Ethel Corporation by that point. That happened in nineteen sixty two. Letted gasoline was gradually phased out and banned around the world over the decades that followed, although there were exceptions. In general, wealthy countries made the switch first, while leaded gasoline continued to be marketed and sold in other parts of the world, with most of the last nations to make the switch being in the Middle East and Africa. The UN Environment Program started a campaign to eliminate leaded gas worldwide in two thousand two, and as we said at the top of the show, that was finally accomplished just last year, as we're recording this in and one last infuriating thing before we move on. Tetra ethel lad wasn't the only anti knock agent being evaluated in the United States in the nineteen twenties. Another was ethyl alcohol or ethanol, which is the most unleaded gasoline today and was actually already in use in some parts of the world while leaded gasoline was being developed. Thomas Midley Jr. And Thomas Boyd looked into ethanol in the nineteen twenties. They knew that in a lot of ways it was superior to tetra ethyl lead that had similar anti knock properties, and since it was made from fermenting sugars or grains, it was renewable. Ethanol can certainly have negative health effects. Ethanol is what's in alcoholic beverages. We know there are risks that come along with that, but as a fuel additive, it is not nearly as toxic as lead. But this was also during the Prohibition era, and although industrial alcohol wasn't prohibited, this still presented some challenges. General motors also had a patent on tetrath a lead as a fuel additive, but not on ethanol, meaning there was a lot more profit potential for the company with leaded gasoline. The petroleum industry was also concerned about the possibility of ethanol overtaking petroleum as a fuel source, so through all the controversy and hearings in the nineteen twenties, fuel companies were insisting that there was no alternative to lead, even though they knew that there was. So let's take a break and maybe go find a pillow to scream into, because that was infuriating. The story of Thomas Midgley Junior's development of dichloro di flora methane or free on and its eventual phasing out is somewhat less infuriating, at least to me than the tucher at the lead saga, because the damaging effects of free on were not known until long after his death, and the response to finding out about how imaging it was was a lot quicker while he was living, free on really did seem like a vastly better option than the toxic or flammable gases that were in use as refrigerants. For example, in nineteen twenty nine, several people died as a direct result of refrigerant leaks, including a cluster of incidents in Chicago. Sometimes this is cited as the reason that Midgley was looking for a better refrigerant, but he actually developed free On in nine. That work was not announced until nineteen thirty, though, so that may be partially to blame for the confusion about why he started working on it. Midgley's actual process for making this discovery is a little bit vague. He was working at GM, which owned frigid Air, and frigid Air was looking for a new refrigerant. Midgley reportedly developed free On as a refrigerant over the span of only three days. He was focused on compounds that included aureene, starting with carbon tetrafluoride. He thought it was promising because if it's boiling point of minus one seven point eight celsius. He also looked at at least one other chlorofluora carbon that was dichloro mono flora methane before focusing on dichloro diflora methane. That chloro diflora methane was marketed as free On twelve. Similarly, to the establishment of Ethel Gasoline Corporation. Kinetic Chemicals was founded to manufacture this substance. That was through a partnership between General Motors and DuPont. Midgley became one of the company's directors. Soon Freon was being widely used in refrigerators and in the first home air conditioners. Again, there's more on that in our History of air Conditioning episode that came out in August of Based on what was known at the time, freon was unquestionably better than other alternatives. It was non flammable, non top toxic, stable, and essentially odorless. Midgley would demonstrated safety by inhaling a big lungful of it and exhaling it to blow out a candle, something that probably would have seriously injured or killed him if he tried it with earlier refrigerants. That doesn't mean it was a great idea. We've already established that he intentionally exposed himself to things to demonstrate their safety when it wasn't necessarily safe. Other chlorofluoro carbons and hydrochlorofluorocarbons, or CFCs and h CFCs followed, along with other applications for them. During World War Two, freon was found to be particularly effective for dispersing insect repellents. Soon, CFCs are being used as propellants in things like hairsprays. At this point, scientists knew the ozone layer existed. Charles Fabri and Enrie Bouisson had measured it for the first time in nineteen sixteen. They and others started studying in and in nineteen fifty six scientists started taking ongoing measurements at the Halley Bay Observatory on Antarctica. The rise of things like commercial air travel and the space Race led to a bigger focus on the ozone layer, as researchers wondered whether emissions from those vehicles would affect the atmosphere. By the nineteen seventies, data from the Halle Bay Observatory and from satellites showed that the ozone layer was being depleted, but it wasn't yet clear why. Then, in nineteen seventy four, Mario Molina and F. Sherwood Roland published a paper in the journal Nature titled Stratospheric sync for chlorofluoro methanes chlorine ADAM catalyzed destruction of ozone. This paper explained that chlorofluoro methanes, which are a type of hydrochlorofluoro carbon destroyed atmospheric ozone. Molina and Roland were awarded the Nobel Prize in Chemistry for this work, along with Paul kritz And, whose work was focused on the ozone depleting ability of nitrogen oxides. Although air and space travel had been seen as potential threats before this point, this research revealed that common household products were a serious problem. CFCs and HCFC's uses propellants in spray bottles, in refrigerators and air conditioning systems, and in plastic foams. These compounds were both inert and volatile, which meant they could be carried high into the atmosphere unchanged. Once they were there, though, UV light broke them down, releasing chlorine into the upper atmosphere, where it acted as a catalyst to break down the ozone layer. Molina and Roland predicted that if CFC use continued at the rate that it was going, eventually the ozone layer would be entirely depleted. The ozone layer helps protect the Earth from UV radiation, and without it, experts predicted sharp increases in things like cataracts and atal skin cancers, as well as damage to crops and ecosystems that are sensitive to UV light. This was caused for alarm, and some places started putting limits on CFC's and h CFC's In the nineteen seventies and early eighties, a conference was also convened in Vienna, Austria, and on March twenty two, twenty nations signed the Vienna Convention for the Protection of the Ozone Layer. This included most of the nations where most of the world CFCs were being produced. This convention set up a framework for nations to work together to try to address this problem. It focused on things like information sharing and research, rather than on taking specific actions to keep the layer from depleting any further. On May one, five, a team led by Joseph Farman at the British Antarctic Survey published another paper in the journal Nature, this one reporting that the ozone layer over Antarctica was already significantly depleted. This depletion was so dramatic that Farming at first thought his instruments were malfunctioning. This heavily depleted area over Antarctica became known as the Whole in the Ozone Layer, but there were other proposed causes for this depletion besides CFCs and h CFCs, and additional research had to be done to confirm what was going on. Then, in the Antarctic Airborne Ozone Expedition took measurements high in the atmosphere which showed that if there was more chlorine monoxide in an area, there was also less ozone. So it was clear that global action was needed to reduce the production and use of ozone depleting substances like CFCs and h CFCs. Building on that framework that had been set up in the Vienna Convention, nations came together again, this time in Montreal. In on September six of that year, forty six countries signed on to the international treaty that came to be known as the Montreal Protocol. Its terms included a phasing out of the production and use of several types of ozone depleting chemicals, setting a target of reducing them to fifty of nine levels by less wealthy countries were allowed a grace period to make the transition, and since then the treaty has been amended to completely ban a range of ozone depleting substances. The Vienna Convention in the Montreal Protocol are the only international treaties that have been signed by every member state of the United Nations. Many ozone depleting substances were completely phased out around the world in the nineteen nineties and early two thousands, and the few that remain are scheduled to be phased out by twenty forty. The ozone layer has already started to recover, and it is estimated that it will be entirely restored by twenty fifty. So when you hear somebody say something like, remember when everybody was freaking out about the ozone layer, and now we never hear a thing about that anymore, kind of implying that it was some kind of manufactured panic, and maybe we can just disregard other alarming reports about things like climate change. The reason we don't hear about it anymore is because the world actually came together to take action to address and fix this problem. Definitively, it can be done. It can especially be done when there are alternatives that exist that are maybe only a little bit more expensive, and you don't have an entire industry is spreading a whole lot of disinformation saying the climate change isn't real? What that's crazy? Hey, do you have a listener? Uh? This listener mail is from Abbey, who sents a note that is titled O MG diarial man and Abby started by saying dearest, just oriens and then the first paragraph of the email has some various personal details, but Abby talks about wanting to be a history major. But because Abby's parents assumed that history majors all became teachers um and did not think that Abby would have the patients to really be a teacher, they discouraged that line of education. But now Abby has become a a an avid listener to the podcast. So now on to the actional actual reason I'm writing. I've been a pharmacist for the last fifteen years, both at the at a retail pharmacy and now as a hospital pharmacist. While I was in school, I discovered a way to meld my love of science and history by studying medical history. My university actually had a History of Pharmacy elective, and it was taught by the most delightful professor ever. Addition to being a PhD in pharmaceutics and a pharmacist, he was also a veteran of World War One. He was a pharmacist in the Battle of the Bulge. I love to hear his stories of pharmacy during the war, especially the way the army recycled penicillin to share with the French civilians. This professor introduced me to the wonders of medical history items available on eBay, and gave me my first antique medical books. Since then, my collection has grown to fill several bookshelves and photos covering the walls of my office. When you mentioned the diarial man and the hypertension episode, I literally jumped up from my sewing machine. I'm a nerdy quilter too, and went directly to the internet. I'm proud to say I found one, and he's on his way to me now. Although drug companies have stopped making and sharing chatzky in the last ten or fifteen years, I always loved when we would get a new set of fancy drug pens, notepads or counting trays. My favorite item I've collected was a pen for the little blue pill that folded in half, and when you needed to use it, you pushed a button on the end and it very comically flipped open in a rather slow and hilarious manner. I'm sure that someone on the Fiser marketing team was very proud of that one. I'm not sure if I should thank you or not for educating me on the possibility to expand my collection to include drug rep paraphnalia or not, but I'm now on the hunt for other antique findes like dire ol Man. I also want to thank you for the rabies episode earlier this year. Thank you for sharing the stories of why we pretty much treat anyone who comes in contact with bats in the US. I made sure to share the information with the pharmacy staff because my hospital has several emergency room visits every year for bat exposures and we almost always end up administering rabies vaccines and immune globulin shots. It was always crazy to my fellow pharmacists and me about why so many people go to the e er when they just have a bat in their house or they accidentally touched a dead bat outside. We often thought people were being overly dramatic, especially when we had a family of eight come in and all needed treatment because we had to call all over the state to get enough vaccine. While I can confirm that the rabies series is a lot of vaccinations for of them over fourteen days. The urban legend stories of the need to use giant needles for shots and the bellies false. But it is quite uncomfortable when there is a bite because we have to inject the immune globulin and small amounts all around the bite location. It doss of immune globulin are based on the patient's wait. It can sometimes end up being a lot of pokes. Apologies for such a long email, but I have attached kitty pictures as penance. Uh, these kiddies are adornable. Um, since as we said, Abby is the pharmacist. These are named after antibiotics. Um, there's I'm gonna say this strong moxic flu accin. It's probably right, moxie. And that's a great tabby. Oh no, that's an orange tabby. And then the great tabby is linkomycin or link Um. I love naming naming the kiddies after antibiotics. I think that's great. So number one, I got this email and I love that. Somebody else was like, I'm gonna go get a direal man, and I'm I'm like our email sellers, like, why is everybody's side like what, I love my diarial man Yeah, Holly already got a direl man um. The other thing was I had to go look up and see how the army recycled penicillin. I had an idea in my head of how probably that happened, and that idea was the correct idea. And I'm not going to go into detail about it right now because it's a little gross for more squeamish people. But I realized, even though I was sure we had like a penicillin episode, I don't actually think we do. We have other antibiotic stuff. I'll double check. If we don't have a penicillin episode, we probably should because the oversimplified children's book story of how penicillin was developed is not, as is often the case, not not really cute. It is very cute and not very complete. So thank you again, Abby for this email and for the cat pictures. If you would like to write to us about this or any other podcast or at history podcasts that I Heart radio dot com. If you're going to write to us to say that climate change is not real, just keep that to yourself because that's incorrect. We are on the I Heart Radio app wherever else you like to get your podcasts and we hope you will tune in next time. Kind of scared you away with our climate talk. Stuff you Missed in History Class is a production of I heart Radio. For more podcasts from I heart Radio, visit the i heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.