@sonhouse saidThe at the guy knew what he was doing, but the $$$ blinded him.
https://interestingengineering.com/thomas-midgley-jr-the-man-who-harmed-the-world-the-most
Such things as Tetraethyl lead additive to gasoline directly from Midgley.
Oh and no automotive travel wouldn't have spread as it did hadn't he marketet his Invention....
@Ponderable
I think the only thing leaded gas gives you is higher octane so you can use higher compression ratios and so have a more powerful engine.
Are you saying that allowed the spread of cars across the US?
I would think it made for more powerful engines and such but I don't think if we never used leaded fuel there would be much less cars on the road today.