Marc Edwards is a civil and environmental engineer who was instrumental in bringing to light both the Washington, D.C. and Flint, Michigan water crises. One of the world’s leading experts in water corrosion in home plumbing, the eccentric Marc Edwards caught Mona’s attention when Elin told her about Marc’s role in exposing a lead-leaching problem in D.C.—and the “radioactive” reputation he earned in the process. When Marc, who’d gotten wind of a potential crisis in Flint, traveled to Michigan to conduct some research and hold a press conference, Mona requested to meet with him—and she was grateful to find a friend and ally in Marc. Over the months that followed, Marc supported Mona’s research and joined her as one of the primary whistleblowers in the Flint crisis.