In searching for a substance that made gasoline less flammable (and hence stopped it from igniting outside of a cylinder, i.e. "knocking") we tried everything including adding melted butter! Lead along with a lot of other things worked well but we went with lead and poisoned generations of people.
Many blame it for the rise in violent crime from the 1960s to 1990s:
https://www.smithsonianmag.com/smart-news/leaded-gas-poison-...
In searching for a substance that made gasoline less flammable (and hence stopped it from igniting outside of a cylinder, i.e. "knocking") we tried everything including adding melted butter! Lead along with a lot of other things worked well but we went with lead and poisoned generations of people.
Many blame it for the rise in violent crime from the 1960s to 1990s:
https://www.forbes.com/sites/alexknapp/2013/01/03/how-lead-c...
Nobody seems to care about any of this.