This summer, I traveled from Park City to Washington, D.C., to talk with lawmakers about something my family learned the hardest way possible: What happens when the public isn’t told what’s in its water. My grandfather developed pulmonary fibrosis after living for years near the 3M chemical waste disposal site in Lake Elmo, Minnesota. There were no warning signs posted around the site. No notices came in the mail. For years, no law required anyo…