Preliminary tests show that a tornado that struck a Superfund site in northeastern Oklahoma did not raise airborne lead levels enough to create a health risk.

U.S. Environmental Protection Agency spokeswoman Tressa Tillman says more testing is being conducted and officials likely will remain in Picher (PITCH’-er) until debris removal is completed.

The tornado Saturday was responsible for seven deaths in the Picher area, where lead and zinc mining once occurred.

Tillman says the EPA found that particulate levels weren’t high enough to raise health concerns.

Prolonged exposure to lead can damage nervous systems, particularly in young children. State and federal officials have been trying to buy out area residents to encourage them to leave.