Radon is a colorless, odorless and tasteless gas that is produced from radioactive breakdown of elements within ground soil. Radon is known to cause cancer, in fact, Radon is the second leading cause of lung cancer with prolonged exposure. Parts of Greenville and Spartanburg County have tested in the EPA’s Red Zone, which means homes have a higher probability of of testing at or above 4 pCi/L and above.