450 North Carolinians are estimated to die each year due to radon-induced lung cancer. Data provided by the Center for Disease Control and Prevention indicated that 77 of the 100 counties in North Carolina have radon indoor air levels above action level of 4 pCi/L.
Although many counties of both North and South Carolina have average testing below the harmful numbers, it is still suggested to test for radon. There have been many isolated areas within those counties where Radon levels have tested at very high levels.
The maps below show that radon level status as determined by the EPA in both North and South Carolina.