Sometimes contemporary scientific studies generate knowledge that questions all that has come before. Or shows that certain innovative, life-saving discoveries used for many years can be dangerous for our health. 

C’est la vie.

Unfortunately, technological progress can also be built on the shoulders of pygmies. That is those with exclusive corporate and profit priorities. Politicians are not immune either.

When that happens, for example, when the inherent lethal dangers of using a new technology are known but wilfully ignored… then it’s probably time to call M to ask for the specialist assistance of 007.

Petrol additive

In this light, I present to you the sad but true case of Thomas Midgely Jr. He was the creator of CFC (ChloroFluoroCarbon) refrigerants and the anti-knock use of the petrol additive tetraethyl lead.

Midgely was an engineer recruited by General Motors (GM) in the USA over 100 years ago. His first task there was to improve the efficiency and lifetime of automobile engines by eliminating 'knocking'.

This process is best described as uncontrolled mini-explosions of fuel taking place in the engine cylinders. The problem is essentially a chemical one and depends upon the exponential production of the highly reactive, short-lived species that chemists call radicals.

Midgely’s strategy went along the route of 'mopping up' the radicals. He first tried to do this by adding ethanol to the gasoline. It worked well and was described by him as the fuel of the future.

That future never came to pass though because the production of ethanol could not be patented and therefore would not generate much profit for GM.

All about profits

The idea in any case was hated by Big Oil because farmers could make ethanol from grain. Even less profits for the corporations.

So he tested many other additives. None of them worked as well as ethanol… until in 1924, he stumbled upon a very effective anti-knock compound called tetraethyl lead (TEL). It was manufactured by the chemical company DuPont, which owned about one third of GM stock.

GM knew how bad lead was for human health because many of their own workers had died or suffered tremors or hallucinations from its toxic effects in the TEL manufacturing process.

Nonetheless 'Ethyl' as TEL became known (quickly dropping the reference to lead) was used in the USA as a fuel additive until 1996 and until the year 2000 in the EU. The age of unleaded petrol had come. But that was not the end of the story.

Even though these bans began to be enforced over 20 years ago, it has been shown that currently about half of the lead polluting London’s air still comes from the residuals of leaded petrol.

Countless children are therefore still at particular risk in many countries because of a corporate decision in the 1920s to use a petrol additive that was toxic but generated more profit than a clean one. 

And living or holidaying in Algeria today — where leaded petrol was finally phased out in 2021 — still poses a daily health risk of lead poisoning.

The use of Ethyl also begs a scientific (rather than economic) quid pro quo. Its use certainly represents a good method for increasing fuel efficiency and the prevention of car engine damage. 

But the adverse health outcomes still remain no matter the benefits to drivers and the public for getting 'old bangers' off the roads.

DuPont’s technological connections to Midgely did not end with Ethyl. They carried on with the synthesis of CFCs for use in refrigerators and air-conditioning units.

For many years, preserving food by keeping it cold depended on the ice-harvesting industry (think Kristoff from Frozen). It was backbreaking work like turf cutting and the search for a technological leap forward from the domestic ice-box was highly competitive.

The earliest refrigerators required ammonia or sulfur dioxide or methyl chloride to take part in the compression-expansion cycle that underpins the cooling process. But these gases are toxic and not really suitable for use in the home.

They certainly were too dangerous to drive air-conditioning units in motor vehicles. Hence General Motors (and its Frigidaire division) became interested in developing safe, inert, non-flammable refrigerants that did not kill people.

In 1928 Midgley and his team delivered just what the GM bosses wanted by synthesising the first chlorofluorocarbon, which they called Freon-12.

Never one for dodging personal risk in testing the safety of his creations, he inhaled a lungful and then blew out a lit candle.

He must have been relieved that no harm was done — unlike the time he washed his hands in tetraethyl lead and spent an extended period after that in convalescence.

Shareholder DuPont was given, unsurprisingly, the task of manufacturing it. And the rest is history.

Professor Sherry Rowland and his postdoctoral worker Mario Molina in the University of California at Irvine (UCI) had much experience in the study of how fast reactions might proceed in the atmosphere.

Standing on the shoulders of the giant, Jim Lovelock, the pair of physical chemists (later to win Nobel prizes) worked out that a mixture of sunlight, CFCs and ozone in the air about 25 km in altitude would result in irreversible ozone layer destruction. 

CFCs' destructive role

And once there, the CFCs would repeatedly play their central role in the massacre.

So the health problems associated with the use of reactive, toxic refrigerant gases at ground level were now replaced by an unforeseen health effect related to the inertness of CFCs. That is the depletion of high-altitude ozone, which inevitably causes harmful UV (ultraviolet) radiation to rain down on us.

At least we can wear a hat and live in a cave to escape the worst of UV radiation exposure. 

But another side effect of the CFCs is that they are very potent greenhouse gases and therefore make important contributions to global warming. What a legacy, you might say.

So where do you stand on Midgley? Hero or villain? 

Was he a simple dupe of corporate America? Did he turn a blind eye to his employer’s behaviour for reasons of loyalty and job security? Does it matter whether he was a knowing or an unknowing participant in the whole sorry saga?

His story raises another, more important, question. Given the fact that scientists are just doing a job, should they ever be blamed for their work-place discoveries?

If you think yes, then ask yourself, should Fermi, Schrödinger and Bohr be blamed for the nuclear bombs that were dropped on Japan in 1945

Thomas Midgely Jr died in 1944 at the age of 55: some of his associates thought he had committed suicide.

John Sodeau is Emeritus Professor of Chemistry at UCC

Mick Clifford is on holiday