Leaded fuel has a long history of causing brain damage to kids exposed to the fumes, and it demonstrably does for kids living near airports as a result of propeller planes burning leaded fuel. The recent development of an unleaded fuel which can work in all the existing aircraft fleet has resulted in a small number of locations needing the sale of leaded fuel, and this will represent a full state-wide end to the use of leaded fuel.
I expect to see improvements in childrens’ intelligence and reductions in crime as over the coming decades as a result.
I am no expert in Aviation or fuel, but there has been high octane unleaded ethanol free fuel options for years (Racing Fuel comes to mind aka mogas) and G100UL has been around for > 15 years aside from other competitors with similar products. It feels like regulations like California’s are the only reason the FAA even started doing anything.
The True Inside Story of the G100UL Fuel Approval (in 22 seconds) by AVweb
Yeah, the fact that several local governments banned leaded fuel sales was a big impetus for the FAA to actually approve the fuel for all piston-driven planes.