“We were able to show through our hair samples what the lead concentrations are before and after the establishment of regulations by the EPA,” said demographer #link(“https://profiles.faculty.utah.edu/u0030780”)[Ken Smith];, a distinguished professor emeritus of family and consumer studies. “We have hair samples spanning about 100 years. And back when the regulations were absent, the lead levels were about 100 times higher than they are after the regulations.”
Apparently there has been some progress towards that, as we needed an alternative additive for piston-engine prop planes to prevent engine knock. You don’t want planes stalling or breaking down.
The FAA has a program to completely eliminate the leaded fuels by 2030, but there is one already available and several more in testing.
https://www.faa.gov/unleaded