Hormesis Breast cancer and DDT
Working with their ancestor one day as a college student, he spritzed the plant with the common herbicide Phosfon, planning to measure how much the poison stunted the plant's growth. But instead of shriveling up, the Phosfon-treated plant grew some 40% taller and leafier than untreated plants.
The herbicide had been mistakenly overdiluted, and thanks to that accident, Ed Calabrese rediscovered a paradox of toxicology that had been in the doghouse since the 1930s: Low doses of a poison can be not merely harmless, but actually beneficial.
Toxicology's "...error of historic proportions."