23/08/2022
Some inventions are bad: sprayable cheese, subprime mortgages, the mankini.
Some inventions are evil: agent orange, the guillotine, spam emails.
Some inventions are in fact so evil that they cannot be patented in the UK on the grounds that they are contrary to ‘ordre public’: cluster munitions, land mines, chemical weapons.
Then there are the inventions which are well intentioned but nonetheless end up being disastrous: dynamite, asbestos, Olestra. Inventions in this last category are often the most intriguing and instructive. Learning from past mistakes is perhaps the best way to avoid unintentional disasters in the future, and any discussion of unintentional disasters must include the story of Thomas Midgley Jr.
Lead On
Thomas Midgley was an American chemical engineer. In the late 1910s, he was working at General Motors trying to solve the problem of engine knocking; spontaneous explosions of the petrol/air mixture in an engine cylinder. Knocking was noisy, inefficient, and damaging to the engine. It was also becoming more common as engines became more powerful and cylinder pressures increased. Midgley tried all sorts of different additives in an effort to increase the combustion pressure of the engine fuel. Camphour, aluminium chloride, and even melted butter were added to petrol to no effect. Midgley did find that the addition of ethanol prevented engine knocking, but you needed lots of it. Moreover, cynics have pointed out that ethanol could be readily produced by any brewer or distiller. Its distribution could not be controlled and monetized. Midgley kept looking.
In December 1921, Thomas Midgley tried adding tetraethyl lead to petrol and the results were astonishing. Engine knocking was eliminated by adding just one part per 1000 of the cheap additive. For his efforts, General Motors was awarded a number of patents directed to this new ‘leaded’ fuel including US 1,575,436 and US 1,575,437. The new additive was marketed as ‘Ethyl’, the word ‘lead’ being conspicuous by its absence. Ethyl was an overnight success and quickly became the standard fuel for the mid 20th century motorcar.
Almost immediately the additive had it’s critics. The harmful effects of lead were well known in the 1920s. Even the Romans understood that water carried in terracotta pipes was preferable to water delivered by lead plumbing. A number of universities and research institutions wrote to the newly formed Ethyl Corporation warning of the dangers. In response, Midgley staged a press conference in which he washed his hands in tetraethyl lead to demonstrate just how safe it was. He was very wrong.
Adding Fuel to the Fire
What Midgley hadn’t told the press was that several workers at the plant producing tetraethyl lead had fallen ill from lead poisoning, five of them sadly died. Midgley himself had succumbed to lead poisoning and spent most of 1923 convalescing in Florida. Over the following decades, the evidence of the harmful effects of tetraethyl lead began to mount. It was discovered that the average American living in the late 20th century had 1000 times more lead in their bones than their pre-industrial ancestors (here), this was directly linked to the introduction of leaded petrol. In addition, it was found that these high lead concentrations were associated with lower IQ and increased behavioural problems in children (here). More shockingly, several studies showed that exposure to high levels of lead during childhood is associated with higher levels of crime, particularly violent crime, in adulthood. This was elegantly tested by economist Jessica Reyes who compared the dates on which leaded fuel was phased out in each US state to the subsequent crime data. She found violent crime fell in almost all states following clean air legislation, and most of this drop could be attributed to the prohibition of tetraethyl lead (here). Similar studies in the UK, Canada, and Australia found that a drop in lead concentrations in the blood of pre-school children corelated, about 20 years later, with a reduction in burglaries (here).
Country by country, leaded fuel was phased out. In the US, it was banned by the Clean Air Act of 1996, although it was already prohibited in a number of states by that point. The UK banned the additive in 2000. The prohibition was finally completed in 2021 when Algeria became the last country to outlaw tetraethyl lead in fuel (here).
Cold Comfort
In the late 1920s Thomas Midgley’s focus pivoted from gasoline to refrigeration. He was tasked with improving the refrigerant gas used in domestic fridges. The most common refrigerants used at the time were toxic (such as sulphur dioxide) or explosive (such as propane). Midgley and his team found that dichlorodifluoromethane was an effective refrigerant without the drawbacks associated with the previous gases (here). For his work, Midgley was again awarded a number of patents including US 1,968,050 and US 2,007,208. The gas was marketed as ‘Freon’ and it belongs to a group of chemicals known as, you guessed it, chlorofluorocarbons or CFCs.
To demonstrate Freon’s safety, Midgley hosted another press conference in which he inhaled a lung-full of the gas and then blew out a candle with it, Freon was clearly both non-toxic and not explosive, it was safe (here). Once again, Midgley was very wrong.
What he didn’t know was that once released, CFC’s float high into the atmosphere where they react with and degrade the ozone layer. The ozone layer typically absorbs over 97% of the Sun’s ultraviolet energy (here), without it life on Earth would be all but impossible. In 1985, the British Antarctic Survey discovered a hole in the ozone layer over Antarctica, and suggested a link to CFCs (here). Governments acted fast. In 1987 the Montreal Protocol was adopted which rapidly phased out CFCs. Remarkably, the Protocol remains the only UN treaty to have been ratified by all 198 UN member states, a triumph of environmental collective action (here). The hole in the ozone layer is now shrinking; our protective ozone shield is expected to be fully recovered by about 2065.
A Lesson Learned?
While it took time, the worst effects of Midgley’s inventions appear to be behind us. But are there inventions we use today which could also have unintended consequences? The most obvious possible analogue to Midgley’s work is the abundance of plastic waste which surround us. As discussed previously by Duncan (here), the potential problem of tiny plastic pollution is slowly creeping to the forefront of the global consciousness. Microplastics have been found everywhere from the top of Everest to the bottom of our oceans. They are in the food we eat, the water we drink, and the air we breathe. More worryingly, in April 2022 scientists discovered tiny plastic fragments deep in the lung tissue of a living human for the first time (here). A number of teams are currently working to determine the extent to which these plastic pollutants may be harmful to humans. Are we on the brink of another Midgely-esque moment? At this point, we just don’t know.
While this may all seem a little disconcerting, the caution we can take from Midgely’s story should be tempered with a good degree of optimism. For both leaded petrol and CFCs, the world (eventually) recognised the problem and took drastic action to solve them both. While much of the change can be attributed to national laws and international treaties, the prohibition of either chemical would not have been feasible if there had not been suitable substitutes waiting in the wings. Today, a number of compounds act as anti-knocking agents including ethanol, which also reduces the engine’s carbon dioxide emissions. CFCs were quickly replaced as refrigerants by hydrofluorocarbons (HFCs) which do not degrade the ozone layer, although sadly they are a potent greenhouse gas.
If in the future it is found that microplastics are harmful to humans, our search for substitute materials will not begin from scratch. In 2019, Joanne reported (here) on several plastic alternatives being developed for specific applications such as algae water bottles, mushroom packaging, and gourd cups. Last year I reported (here) that the number of European patent applications filed annually directed to biodegradable plastics has more than tripled between 2005 and 2019. While there is clearly work to do, development in plastic alternatives is going in the right direction and should soon be part of our every day life, regardless of whether or not microplastics are found to be harmful to humans.
Midgley’s Final Invention
Author Bill Bryson once described Thomas Midgley as having “an instinct for the regrettable that was almost uncanny” (here), and he has been called a “one man environmental disaster”. But surely Midgley’s story is really one of hope. In the face of Midgley’s catastrophic invention, humanity has demonstrated its incredible capacity to adapt in relatively short order, not once but twice.
Midgley was a brilliant man. He was awarded over 100 patents in his lifetime, and he never stopped inventing. In 1940 he contracted polio which left him severely disabled. Ever the inventor, he devised an elaborate system of ropes, pulleys, and hoists to get him out of bed. In 1944 while using the system, he became tangled in the rope and died of strangulation. Sadly this time no one could save him from his invention.
This article is for general information only. Its content is not a statement of the law on any subject and does not constitute advice. Please contact Reddie & Grose LLP for advice before taking any action in reliance on it.
