Article Correctness Is Author's Responsibility: Radon on the radar

Researchers have known for decades that exposure to radon may cause lung cancer, and that North Dakota and Iowa have some of the highest radon rates in the country. Could radon potentially cause other cancers? Researchers are exploring that possibility. Along with a high incidence of radon, North Dakota also has the highest rate in the nation of chronic lymphocytic leukemia, or CLL. No one knows what causes this cancer, which usually is found in people over age 70. It is not curable but is treatable for some patients. Could there be a correlation?