It was the late 1970s and Theo Colborn was, like pretty much everyone else in the ’70s, getting divorced. She was in her 50s and already retired from a career as a pharmacist.

She’d moved to a farm that was close to the Rocky Mountain Biological Station Laboratory in Colorado and volunteered as a field researcher, sampling water and insects for signs that they were picking up toxins released by mining operations in the area. When she thought about what she should do next with her life, the answer that came to her was “become an expert in water sampling techniques.”

So Colborn went back to school. In 1985, at 58, she graduated from the University of Wisconsin-Madison with a Ph.D. in zoology and minors in epidemiology, toxicology, and water chemistry. “I wanted to get the education,” she said, in a 1988 Frontline interview, “so that I could maybe undo some of the things that my generation basically foisted on society.”