A century of hair samples proves leaded gas ban worked

Science has also produced a hero in this saga: Caltech geochemist Clair Patterson. With George Tilton, Patterson developed a lead dating method and used it to calculate the age of the Earth (4.55 billion years), based on analysis of the Canton Diablo meteorite. And he quickly became a leading advocate for banning leaded gasoline and “lead solder” used in canned foods. This put Patterson at odds with some powerful industrial lobbies, for which he paid a professional price.

But his numerous experimental findings on the extent of lead contamination and its toxic effects ultimately led to the rapid elimination of lead in all standard automobile gasolines. Before the EPA’s actions in the 1970s, most gasoline contained about 2 grams of lead per gallon, which quickly adds up to nearly 2 pounds of lead released into the environment through automobile exhaust, per person each year.

The proof is in our hair

Lead can persist in the air for several days, contaminating the lungs, accumulating in living tissues, and being absorbed through the hair. Cerling had already developed techniques to determine where animals lived and their diet by analyzing hair and teeth. These methods proved ideal for analyzing hair samples from Utah residents who had already participated in a previous study involving blood samples.

Subjects provided hair samples from today and from their very young ages; some were even able to provide hair preserved in family albums that belonged to their ancestors. Utah’s population lends itself well to such a study, as the towns of Midvale and Murray were home to a vibrant foundry industry for most of the 20th century; most other smelters in the region closed in the 1970s when the EPA cracked down on the use of lead in consumer products.