Piles of boric acid
"April 2002: Photos from a videotape of the [Davis-Besse nuclear power plant] reactor's lid taken shortly after the large hole was found show piles of boric acid. The acid had accumulated for years, in roughly the same area that workers identified in 1998. FirstEnergy now acknowledges that since at least 1996 the lid had not been completely cleaned or thoroughly inspected," Cleveland Plain Dealer, Dec 1, 2002.
