Why was the town of picher, oklahoma, evacuated in 2009?

The town of Picher, Oklahoma was evacuated because it was declared uninhabitable because this town used to service some mines which made the environment harmful to people.

Explanation:

There were some subsurface excavations in this town which had bad effects on some town's buildings and at the same time these excavations produced mine tailings which were toxic metals that contaminated the area.

The state took some measures to reduce the contamination but in 1996 a study showed that 34% of the children in this town were suffering from lead poisoning because of the problems in the environment. Lead poisoning  could produce neurological problems.

Finally, On September 1, 2009, the town of Picher did not belong to the state of Oklahoma anymore and all the operations in this town were suspended.