Is Potassium-40 Harmful?

The radiation that is emitted from the 40K, which accounts for only 0.012 percent (120 ppm) of the total amount of potassium that can be found in nature, does not pose any significant risk. The half-life of potassium-40 may be calculated using electron capture and beta decay. Radiation emitted by potassium chloride is not much more radioactive than the radiation that occurs naturally in the environment.