Geochemist

They didn't start out as environmental warriors. Clair Patterson was a geochemist focused on determining the age of the Earth. Herbert Needleman was a pediatrician treating inner-city children. But in the chemistry lab and the hospital ward, they met a common enemy: lead. It was literally everywhere - in gasoline and paint, of course, but also in water pipes and food cans, toothpaste tubes and toys, ceramics and cosmetics, jewelry and batteries. Though few people worried about it at the time, lead was also toxic.