Electromagnetic radiation has many uses, but some of the waves can have hazardous effects, particularly on human body tissues.
Ultraviolet waves, X-rays and gamma rays are types of ionising radiation. This means that they can knock electrons from the shells of atoms, turning them into ions. This process of ionisation can lead to mutations in cells, which can lead to cancer.
Ultraviolet waves can cause skin to age prematurely and increase the risk of skin cancer. Gamma rays can also damage or kill the cells in a person's body. In order to be safe, exposure to ionising radiation needs to be kept as low as possible, especially for people who work with this type of radiation every day in hospitals. A radiographer using X-rays in a hospital has to stand behind a lead shield or be in another room when the X-ray machine is being operated.