Since World War II, radiation has been in the news and is often associated with weapons and disaster. The atom bomb, Three Mile Island, Chernobyl, and recently the Fukushima Daiichi nuclear plant in Japan are but a few examples. However, for many people utilizing radiation in its several forms is just an everday part of the normal work day.
Radiation-emitting devices and materials are found in the home and workplace. One of the most familiar is the common smoke detector which uses americium, a man-made element. X-ray machines used in the dentists' and doctor's office as well as in hospitals also deliver radiation energy. Some hospital equipment, such as a computed tomography (CT) scanner or a fluoroscope deliver radiation.
OSHA separates radiation into two categories, non-ionizing and ionizing. Non-ionizing radiation includes:
- EXTREMELY LOW-FREQUENCY (ELF) RADIATION
- ELF Includes alternating current (AC) fields and other electromagnetic, non-ionizing radiation from 1 Hz to 300 Hz. As a point of reference, electrical lines operate at a frequency of 60 Hz. Some studies have suggested an increase in cancer risk from ELF, but the medical evidence is inconclusive. Currently, there are no specific OSHA standards that address ELF radiation fields.
- RADIOFREQUENCY (EF) AND MICROWAVE (MW) RADIATION
- RF radiation ranges between 3 kilohertz (kHz) and 300 Megahertz (MHz), while MW radiation ranges between 300 MHz and 300 gigahertz (GHz). The main hazard to humans from RF and MW radiation is tissue damage caused by heat. Some studies suggest an increase in cancer risk and tissue damage from RF radiation. There are currently no OSHA standards regarding RF and MW radiation, but they are covered by other agencies.
- LASERS
- Lasers are high-intensity beams that can cause burns and eye damage. Laser hazards are addressed in specific standards for protective equipment and procedures.
Ionizing radiation can strip electrons from their atoms resulting in genetic damage, mutations and cancers. Ionizing radiation are typically described by letters:
- ALPHA RAYS
- The alpha rays are made up of particles containing two protons and two neutrons, a helium nucleus. These are emitted by the decay of radioactive materials and are of low enough energy to be stopped by a sheet of paper or even by smoke, which make them useful in home smoke detectors.
- BETA RAYS
- Beta rays are high-energy electrons and positrons emitted from the nucleus of radioactive materials. Beta rays can damage the body directly. They emit X-rays as they lose energy.
- X-RAYS
- X-rays are used extensively in medicine and industry. X-rays are high-energy electromagnetic radiation that can penetrate tissue and materials, but they cause damage along the way. Exposure to X-rays must be limited in medical application and avoided in industrial applications.
- GAMMA RAYS
- Gamma rays are powerful, high-energy electromagnetic radiation. They are similar to x-rays, but more powerful and penetrating.
Neutrons, high-speed electrons, high-speed protons and other atomic particles ejected by decaying atoms also present an ionizing hazard.
OSHA addresses radiation although not all forms of radiation are covered under OSHA guidelines. Radiation effects and safety issues are also addressed by the Centers for Disease Control and Prevention in Atlanta.
References:
http://en.wikipedia.org/wiki/Alpha_ray
http://en.wikipedia.org/wiki/Beta_radiation
http://en.wikipedia.org/wiki/Gamma_ray