John Oliver seems quite taken by Danbury, Connecticut’s history as the Hat City, but hatmaking came at a price: the mercury used to make felt  for hats caused mercury poisoning. The resulting tremors were even  nicknamed “the Danbury shakes.” But while Connecticut banned mercury for  hatmaking, the mercury previously emitted never actually left the  environment, and new sources of mercury such coal plants and artisanal and small-scale gold mines are still putting new mercury into the  atmosphere, leading to catastrophic environmental, economic, and human health impacts. Today, we break down why we’re exposed to mercury, what effects it has, and how we can improve. With special guest Dr. Noelle Eckley Selin: Associate Professor of Data, Systems, and Society and Earth, Atmospheric, and Planetary Sciences at the Massachusetts Institute of Technology and the co-author of “Mercury Stories: Understanding Sustainability through a Volatile Element” which comes out  on October 20th.