Hair Today, Lead-Free Tomorrow

A Utah tradition of preserving family keepsakes just helped prove that environmental regulations actually work.

U researchers analyzed hair samples spanning a century and found lead concentrations have plummeted 100-fold since 1916. The key to documenting this dramatic decline? People who kept their ancestors’ hair in scrapbooks.

“We were able to show through our hair samples what the lead concentrations are before and after the establishment of regulations by the EPA,” says demographer Ken Smith, Distinguished Professor emeritus of family and consumer studies. “Back when the regulations were absent, the lead levels were about 100 times higher than they are after the regulations.”

Before the Environmental Protection Agency was established in 1970, Americans were surrounded by lead from industrial sources, paint, water pipes, and, especially, car exhaust. The neurotoxin accumulates in human tissue and causes developmental problems in children.

For the study, researchers asked families participating in the U’s Utah Population Database to provide contemporary hair samples plus any preserved samples from their youth or from ancestors. Forty-eight people obliged, some retrieving locks dating back a century.

“The Utah part of this is so interesting because of the way people keep track of their family history,” Smith says. “I don’t know that you could do this in New York or Florida.”

Hair samples revealed lead levels as high as 100 parts per million before 1970. By 1990, that dropped to 10 ppm. In 2024, levels measured less than 1 ppm.

“We should not forget the lessons of history,” says co-author Thure Cerling, Distinguished Professor of geology and biology. “Those regulations have been very important.”