Millions of people across the U.S. have been exposed to toxic PFAS chemicals in their drinking water, according to a new report from Northeastern University and the Environmental Working Group.

The report found that at least 610 sites in 43 states were contaminated with the fluorinated compounds known as PFAS chemicals as of March 2019, including the drinking water systems for around 19 million people. According to the Centers for Disease Control and Prevention (CDC), exposure to PFAS chemicals can lead to increased risk of cancer as well as immune, behavioral and reproductive health issues. The nonprofit Environmental Working Group and the Social Science Environmental Health Research Institute at Northeastern University used information from the Pentagon and water utilities to update an interactive map detailing the spread of the contamination. The Environmental Working Group said that when the map was last updated in July 2018, there were 172 locations in 40 states showing PFAS contamination. Based on the new data, Michigan tops the list of states with the most contaminated sites on the map with 192, followed by California with 47 and New Jersey with 43. PFAS contamination was found at 117 military bases across the country, due to use in aviation-grade firefighting foam. The U.S Department of Defense officials estimate that it will cost $2 billion to clean up the contamination at all bases in the U.S., Military Times reported. "This should be frightening to all Americans in many ways," David Andrews, a senior scientist with the Environmental Working Group, told CBS News. "These chemicals ... don't break down in our body and they don't break down in our environment and they actually stick to our blood. So levels tend to increase over time."