Through the last part of the twentieth century, awareness grew of the extreme toxicity of the giant chat piles.  In the 1960's, contaminated water from the mines turned the local creek red and the giant chat piles were found to be laced with lead and other poisonous chemicals.  Picher's cancer levels skyrocketed.  

Despite the deadly environment and lead poisoning in 34 percent of the town's children, most residents didn't leave until experts discovered the town was in imminent danger of collapsing into the mines, a legacy of more than a century of unrestricted subsurface excavation.  Picher was declared too unstable for human habitation and too toxic to clean up.  By 2008, an EF-4 tornado demolished what was left of the town and the city ceased operations the next year.