Banning lead in gas worked. The proof is in our hair

“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.”