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There are two types of radiation: ionizing, and non-ionizing. Radioactive material can be defined as any material that spontaneously emits radiation, and covers a wide range of items, from spent nuclear fuel, to medical supplies, and radium-dial watches. Ionizing radiation applies to all types of radiation originating from alpha, beta, and gamma rays, X-rays, neutrons, and high-speed electrons and protons. Ionizing radiation sources can be found in a wide range of occupational settings, including healthcare facilities, research institutions, nuclear reactors and their support facilities, nuclear weapon production facilities, and other various manufacturing settings.
Exposure/Effects
As a rule, the dangers of radioactive exposure are less visible than those of other hazardous materials, and the presence of dangerous levels of radioactivity is hard to detect; it can only be detected with special monitors. Its effect on the human body may not be evident for days, weeks, or even years after exposure occurs. As ionizing radiation is applied to humans, the effects may include dermatitis, redness of the skin, skin cancer, hair loss, and eye inflammation.
The human body is able to tolerate a certain level of ionizing radiation; after all, we are continuously exposed to ionizing radiation from natural sources, such as cosmic radiation from outer space, and from radioactive materials in the earth. The degree of injury that is inflicted on a person by radiation exposure depends on several factors, such as the amount of the radiation dose, the duration of the dose, the rate at which the dose was received, the type of radiation received, and the body parts receiving the dose.
Protection
The annual permissible dose for total body exposure is five rem per year, with three rem permitted within a 13-week period. (Rem is a measure of the dose of any ionizing radiation to body tissue in terms of its estimated biological effect relative to a dose of one roentgen of X–rays).
No part of the body should be directly exposed to radiation. If there is a danger of exposing a body part, appropriate protection must be used. Lead aprons, gloves, and goggles should be worn by workers located in the direct field or in areas where radiation levels from scattering are high. All protective equipment should be checked annually for cracks in the lead and other signs of deterioration. For consistently elevated exposure, a thyroid shield and leaded glasses are recommended.
Scope
The regulations cover employees not protected by the Nuclear Regulatory Commission (10 CFR 20).
Regulatory citations
- 29 CFR 1910.1096 — Ionizing radiation
Key definitions
- Dose: The quantity of ionizing radiation absorbed, per unit of mass, by the body or by any portion of the body. When the provisions in this section specify a dose during a period of time, the dose is the total quantity of radiation absorbed, per unit of mass, by the body or by any portion of the body during such period of time. Several different units of dose are in current use.
- High radiation area: Any area, accessible to personnel, in which there exists radiation at such levels that a major portion of the body could receive in any one hour a dose in excess of 100 millirem.
- Personnel monitoring equipment: Devices designed to be worn or carried by an individual for the purpose of measuring the dose received (e.g., film badges, pocket chambers, pocket dosimeters, film rings, etc.)
- Rad: A measure of the dose of any ionizing radiation to body tissues in terms of the energy absorbed per unit of mass of the tissue. One rad is the dose corresponding to the absorption of 100 ergs per gram of tissue (1 millirad (mrad) = 0.001 rad).
- Radiation: Includes alpha rays, beta rays, gamma rays, X-rays, neutrons, high-speed electrons, high-speed protons, and other atomic particles; but such term does not include sound or radio waves, or visible light, or infrared or ultraviolet light.
- Radiation area: Any area, accessible to personnel, in which there exists radiation at such levels that a major portion of the body could receive in any 1 hour a dose in excess of 5 millirem, or in any 5 consecutive days a dose in excess of 100 millirem
- Radioactive material: Any material which emits, by spontaneous nuclear disintegration, corpuscular or electromagnetic emanations.
- Rem: A measure of the dose of any ionizing radiation to body tissue in terms of its estimated biological effect relative to a dose of 1 roentgen (r) of X-rays (1 millirem (mrem) = 0.001 rem). The relation of the rem to other dose units depends upon the biological effect under consideration and upon the conditions for irradiation.
- Restricted area: Any area access to which is controlled by the employer for purposes of protection of individuals from exposure to radiation or radioactive materials.
- Unrestricted area: Any area access to which is not controlled by the employer for purposes of protection of individuals from exposure to radiation or radioactive materials.
Summary of requirements
- All individuals working in or frequenting any portion of a radiation area shall be informed of the occurrence of radioactive materials, or of radiation in such portions of the radiation area. 1910.1096(i)(2)
- Employees shall be instructed in the safety problems associated with exposure to radioactive materials or radiation, and in precautions or devices to minimize exposure. 1910.1096(d)
- Employees shall also be instructed in the applicable provisions of 1910.1096 for the protection of employees from exposure to radiation or radioactive materials, and shall be advised of reports of radiation exposure which employees may request pursuant to the regulations. 1910.1096(i)(3)
- Caution signs, labels, and signals must meet the requirements at 1910.1096(e).
- The immediate evacuation warning signal must be as outlined in 1910.1096(f). All employees whose work may necessitate their presence in an area covered by a warning signal shall be made familiar with the actual sound of the signal—preferably as it sounds at their work location. Before placing the system into operation, all employees normally working in controlled areas shall be made acquainted with the warning signal by actual demonstration at their work locations.
- Employers must notify OSHA of any incident involving radiation which exceeds exposure limits. 1910.1096(l)
- Employers must maintain records of the radiation exposure of all employees for whom personnel monitoring is required. 1910.1096(n)
- Employers must disclose former employees’ records to them at their request. 1910.1096(o)