Picher, Oklahoma is considered the most toxic place in the United States.
The town of Picher, Oklahoma has been ravaged by industrial mining; so much so that a majority of it's inhabitants have fled and it's current population is 20. According to the Environmental Protection Agency, the little town is the most toxic region in all of the United States.
There have been numerous reports of sinkholes appearing overnight as mine shafts collapse. Often, underground water, highly acidic and concentrated with heavy metals, come bubbling into these sinks and turns them into toxic ponds.