Clair Patterson was a geochemist born in Mitchellville, Iowa, United States. He graduated from Grinnell College in Grinnell, Iowa, received his Ph.D. from the University of Chicago, and spent his entire professional career at the California Institute of Technology.
In collaboration with George Tilton, Patterson developed the uranium-lead dating method into lead-lead dating, and by using lead isotopic data from the Canyon Diablo meteorite, he calculated an age for the Earth of 4.55 billion years; a figure far more accurate than those that existed at the time and one that has remained largely unchanged since 1956.
Patterson had first encountered lead contamination in the late 1940s as a graduate student at the University of Chicago. His work on this led to a total re-evaluation of the growth in industrial lead concentrations in the atmosphere and the human body, and his subsequent campaigning was seminal in the banning of tetraethyllead in gasoline, and lead solder in food cans.