Superfund Sites are notorious for taking a long time to resolve. Superfund settlements are intended to provide settling parties with finality. The incorporation of reopener clauses in Superfund settlement agreements, typically required by EPA, and changes in the regulation of contaminants can undermine this goal. EPA's recent decisions to list certain PFAS chemicals as hazardous substances and lower risk levels for lead and 1,4-dioxane has dramatically increased the likelihood that Superfund Sites across the country may be reopened.