At a Glance New study finds the two-thirds of all Americans have unhealthy levels of the carcinogenic chemical chromium-6.Chromium-6 was made famous by environmental activist Erin Brockovich and the 2000 film of the same name starring Julia Roberts. High levels of chromium-6 are tainting the drinking water of 218 million Americans, a new study says. According to a study by the research and advocacy nonprofit Environmental Working Group (EWG), the carcinogenic chemical made famous in the 2000 movie "Erin Brockovich"...