Claire Patterson's contributions to science ranged from developing dating techniques using radioactive decay to alerting the public about the dangers of lead, although he began his career as an emission and mass spectroscopist with the Manhattan Project in 1944. Much of Patterson's professional career was spent as a research associate of environmental science at California Institute of Technology (Caltech) until his retirement in 1992. His early studies focused on using isotopes to date rocks--a process that enabled him to estimate the age of the earth. Later research on lead levels in the environment and their dangers to public health proved fundamental to the enactment of the Clean Air Act in 1970. He was elected to the National Academy of Sciences in 1987; his other honors include having a mountain and an asteroid named after him.

Claire Cameron Patterson was born in Des Moines, Iowa, on June 2, 1922, to Claire Cameron Patterson, a rural...