Efforts to clean up the site began in 1984. The Environmental Protection Agency and the Department of Energy decided to build the cell because it was deemed safer than transporting the toxic wastes elsewhere. Construction began in 1997 and the first loads of waste were added the next year. The last of the waste was placed in the cell in June 2001 and the cap (the mound) was finished in October of that year. The interpretive center opened in 2002.