Radiation may be defined as energy traveling through space. Non-ionizing radiation is essential to life, but excessive exposures will cause tissue damage. All forms of ionizing radiation have sufficient energy to ionize atoms that may destabilize molecules within cells and lead to tissue damage. Radiation sources are found in a wide range of occupational settings. If radiation is not properly controlled it can be potentially hazardous to the health of workers. The following link to information about non-ionizing and ionizing radiation in the workplace. (1) Non-Ionizing Radiation Electromagnetic radiation ranging from extremely low frequency (ELF) to ultraviolet (UV) comprise non-ionizing radiation. ELF Radiation | RF/MW Radiation | IR | Visible | UV | Laser Radiation. (2) Ionizing Radiation. The two types of ionizing radiation are particulate (alpha, beta, neutrons) and electromagnetic (x-rays, gamma rays) radiation. Particulate Radiation | Electromagnetic Radiation. Electromagnetic Radiation: The most familiar form of electromagnetic (EM) radiation is sunshine, which provides light and heat. Sunshine consists primarily of radiation in infrared (IR), visible, and ultraviolet (UV) frequencies. Lasers also emit EM radiation in these "optical frequencies." The higher frequencies of EM radiation, consisting of x-rays and gamma rays, are types of ionizing radiation. Lower frequency radiation, consisting of ultraviolet (UV), infrared (IR), microwave (MW), Radio Frequency (RF), and extremely low frequency (ELF) are types of non-ionizing radiation. Radiation: OSHA Training and Reference Materials Library. Provides several presentations and lectures on radiation, including non-ionizing radiation. The Electromagnetic Spectrum: Michigan Technological University (MTU). Describes the electromagnetic spectrum. See more from topic source: https://www.osha.gov/html/a-z-index.html