As far back as the 1970s, studies conducted by the Department of Defense showed that the firefighting foam used on military bases and ships known as aqueous film-forming foam, or AFFF, that contain the fluorinated chemicals now known as PFAS were toxic.
By the 1980s, animal studies conducted by the Air Force revealed that PFAS chemicals could pose environmental and health risks. Here is a timeline of internal DOD studies and reports detailing just how much they knew about the dangers of using AFFF.