An anonymous reader quotes a report from Business Insider: A new study out Tuesday in the journal Environmental Science and Technology Letters looked at a national database that monitors chemical levels in drinking water and found that 6 million people were being exposed to levels of a certain chemical that exceed what the Environmental Protection Agency considers healthy. The chemicals, known as poly- and perfluoroalkyl substances, or PFASs, are synthetic and resistant to water and oil, which is why they're used in things like pizza boxes and firefighting foam. They're built to withstand the environment. But PFASs also accumulate in people and animals and have been observationally linked to an increased risk of health problems including cancer. And they can't be easily avoided, like with a water filter, for example. You can view the chart to see the tested areas of the U.S. where PFASs exceed 70 ng/L, which is what's considered a healthy lifetime exposure.