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Radiation, Ionizing and Non-Ionizing

Radiation, Ionizing and Non-Ionizing

Hazard Overview

Hazard Overview

What is ionizing radiation?

Ionizing radiation is any electromagnetic or particulate radiation capable of producing ion pairs by interaction with matter. It consists of directly or indirectly ionizing particles or a mixture of both. 

What is meant by directly ionizing and indirectly ionizing particles?

Directly ionizing particles are electrically charged particles that have sufficient kinetic energy to produce ionization by collision. These include, but are not limited to, electrons, protons, alpha particles (helium nucleus) and beta particles (high energy electrons).

Indirectly ionizing particles are uncharged particles that can release directly ionizing particles or can initiate a nuclear transformation. Examples include, but are not limited to, neutrons and gamma rays.

What is non-ionizing radiation?

Non-ionizing radiation is a series of energy waves composed of oscillating electric and magnetic fields traveling at the speed of light. Non-ionizing radiation includes ultraviolet (UV), visible light, infrared (IR), microwave (MW), radio frequency (RF), and extremely low frequency (ELF). Non-ionizing radiation does not have enough energy to remove an electron from an atom or molecule.

What are the hazards associated with ionizing radiation?

Overexposure and unprotected exposure to ionizing radiation can result in cellular damage caused by the interaction of directly ionizing and indirectly ionizing particles with the atoms and molecules of tissue. Because directly ionizing particles are charged, they produce ionizations at very short intervals whereas indirectly ionizing particles can penetrate deeper into tissue before interacting by the production of directly charged particles from within and causing further damage.

What are the hazards associated with non-ionizing radiation?

Non-ionizing radiation is found in a wide range of occupational settings and can pose a considerable health risk to potentially exposed workers if not properly controlled. The type of health effects depends upon the frequency and intensity of the emitting source.

The issue of health effects associated with exposure to extremely low frequency non-ionizing radiation is very controversial and no definitive cause and effect has been identified. Radiofrequency and microwave radiation at sufficiently high intensities can cause skin damage through heating. The skin and eyes absorb infrared radiation as heat. Ultraviolet radiation has a high photon energy and may not result in immediate effects. Lasers, which commonly operate in the UV, visible and IR frequency ranges, are a primary skin and eye hazard.



What can I do to protect myself from ionizing radiation?

Never work with ionizing radiation unless you have been trained and are authorized to use it. In addition to the use of proper personal protective equipment, be sure that shielding appropriate to the type of ionizing radiation is in place to isolate the radiation when in use. Always wear passive dosimeters when working with ionizing radiation to monitor the exposure dose received.

What can I do to protect myself against non-ionizing radiation?

Workers should become aware of the type of non-ionizing radiation that they may be using and/or to which they may be exposed and wear the appropriate type of personal protective clothing and equipment (e.g., eye protection with appropriate tint) or take the necessary precautions.

What resources are available to assist employers?

PPE hazard assessment can be downloaded and customized to fit an individual workplace. In addition, a presentations on PPE can be used for employee training. More resources can be found on the A-Z safety and health topics pages for hazardous waste operations and emergency response and personal protective equipment. The Which OSHA Standards Apply webpage can also help identify other standards that may be applicable to your worksite.

Further, the NCDOL Library offers free safety and health videos and related research assistance on consensus standards (i.e., ANSI, NFPA, NEC). The education, training and technical assistance bureau provides free online safety and health training and outreach services (i.e., speaker's bureau requests, safety booths) upon request. Lastly, the consultative services bureau provides free and confidential onsite consultation regarding worksite safety and health hazards.



Which standards apply?

OSH has adopted the following standards in North Carolina:

Ionizing radiation

Non-ionizing radiation

  • General Industry

    • 29 CFR 1910.97 - nonionizing radiation - covers radiofrequency region, including microwaves, but does not cover ultraviolet radiation or infrared radiation

  • Construction Industry

    • 29 CFR 1926.54 - nonionizing radiation - primary focuses on the use of laser equipment

    • 13 NCAC 07F .0203- nonionizing radiation - removes Class I lasers from 29 CFR 1926.54

  • Other OSH standards associated with exposure to non-ionizing radiation include:


Learn More

Learn More

Where can I learn more?

If you would like to receive interpretive guidance on this or any other OSH standard or topic, you can submit your questions using the Ask OSH web form, by e-mail to or by calling 919-707-7876.