PFAS, often described as “forever chemicals,” are a class of toxic, synthetic compounds that last for a very long time in the environment and accumulate in the human body. Their pervasive use across the country, along with their many associated health risks, have created an emerging contamination crisis. Another type of chemical, 1,4-dioxane, contaminates the groundwater under a large area on the west side of Ann Arbor, and in neighboring communities. These two contamination challenges represent pressing health concerns for residents in the Huron River Watershed. In this class session, we will discuss the behavior of PFAS and 1,4-dioxane, the risks from each, what is being done to address those risks, and how we can avoid widespread contamination like this in the future.