Aqueous film-forming foam (AFFF) is used to suppress liquid-based fires and is commonly used in places like airports and military bases where fires are inadvertently started by oil and fuel. Firefighting foam is a leading cause of per- and polyfluoroalkyl substances contaminating drinking water. Per- and polyfluoroalkyl substances dissolve easily in water and contaminate natural areas that supply a local population with drinking water. Firefighting foam is used in fire suppression and mandatory testing at high-risk locations like airports, refineries, and military bases. The states that have banned aqueous film-forming foam still allow it in instances when there is no alternative solution.

The Department of Defense has identified 687 military installations that will require treatment for per- and polyfluoroalkyl substances released by firefighting foam. The Department has already spent over $3 billion on this clean-up, including providing bottled water and installing water treatment facilities.

Since the 1940s, man-made chemicals known as per- and polyfluoroalkyl substances(PFAs) were used in various applications including adhesives and coatings. The United States military began using firefighting foam containing these chemicals in the 1960s. The Environmental Protection Agency linked these substances to health hazards for firefighters and people residing near military bases or other places where the groundwater was contaminated. Individuals who have suffered health issues and cities with toxins in their drinking water due to firefighting foam are filing lawsuits against the companies that manufacture these chemicals. There are currently over 2,000 lawsuits pending in multidistrict litigation based in the United States District Court for the District of South Carolina.