Why is radioactive radiation dangerous to the body?

Radioactive radiation has enough energy to affect atoms in living cells and thus damage their genetic material (DNA). Exposure to very high levels of radiation, such as close to an atomic explosion, can cause acute health effects such as skin burns and acute radiation syndrome (“radiation sickness”). It can also lead to long-term health effects such as cancer and cardiovascular disease. Exposure to low levels of radiation found in the environment does not cause immediate health effects, but does not significantly affect our overall cancer risk.