In 1942 the Manhattan Engineering District created the first self-contained nuclear chain reaction at the University of Chicago. The uranium oxide used in this critical reaction was produced by the Destrehan Street Refinery and Metal Works - this later became Mallinckrodt Chemical Works. Afterwards the Manhattan Project contracted Mallinckrodt Chemical Works to continue to produce its enriched uranium. St. Louis was only one location in this assembly line of atomic production, but its position has had lasting effects in the St. Louis Region and the world at large.

Between 1947 and the mid 1960s, waste from the Manhattan Project was under the care of the Atomic Energy Commission (AEC). This waste consisted primarily of leached barium sulphate cake residue and was stored in North West St. Louis, now known as the St. Louis Airport Sites (SLAPS). In 1962 a private company bought the uranium and radium processing wastes stored at SLAPS by the AEC, and moved it in 1966 to the Hazelwood Interim Storage Site (HISS) at 9200 Latty Avenue. Due to change of ownership of this private company, much of the radioactive waste was sold and shipped to Canon City, Colorado. The rest, mostly leached barium sulphate cake residue, was diluted with soil and taken to West Lake Landfill, not as a waste product, but as a capping material between daily doses of home waste.