State health officials plan to retest two residential wells where radioactive materials were found near the Oconee Nuclear Station.
But Mary Nguyen Bright with the Department of Health and Environmental Control says the radioactive materials are probably naturally occurring in the mountainous terrain.
Nguyen Bright said earlier testing found uranium, radon or radium close to or above the allowable levels in two of 10 wells tested.
She said officials think the levels are not related to the three reactors at Duke Energy's plant because there was no unusual level of tritium, an indicator of manmade radioactivity.
The additional tests will be done today. DHEC also is retesting wells near the Catawba Nuclear Station in York County and the V.C. Summer Station in Fairfield County.