Radon-220 is a radioactive gas that is part of the uranium decay series. It is produced from the decay of thorium-232 and has a half-life of about 55 seconds, making it a short-lived isotope. Due to its rapid decay, it does not accumulate in the environment like other radon isotopes. This gas is primarily found in certain types of soil and rock, especially in areas with high thorium content. While it is less commonly discussed than radon-222, it can still pose health risks if inhaled, as it can lead to lung damage and increase the risk of lung cancer.