"Chat" the waste product of lead and zinc mining has left over 75 million tons of ground rock contaminated with lead and iron surrounding the town of Picher Oklahoma. Picher is considered the most toxic site in the US was the top priority for the Tar Creek Superfund. The EPA has declared Picher to be one of the most toxic areas in the United States, and beyond being able to be cleaned up. A government buyout, and a devastating tornado in 1998 turned a once thriving mining town into a ghost town almost overnight. Picher ceased to exist offically as a town on Sept. 1, 2009.