How a school shutdown resurrected concerns over nuclear contamination in North Saint Louis

Last October, Jana Elementary School in Florissant, Missouri shut down after an independent study found radioactive lead dust in the school building.

The incident brought light back on a decades-old issue in the community -- nuclear waste that has seeped into the environment throughout North St. Louis County.

The waste is the product of the country's earliest nuclear programs. Starting in the 1940s with the Manhattan Project and continuing through the beginning of the Cold War, downtown St. Louis' Mallickrodt Chemical Works was responsible for processing uranium ore.

"By July of 1942, they were producing one ton of purified uranium a day," Wendy Verhoff, a history professor at St. Louis Community College, told "Nightline."