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 5 rem per year, with 3 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
Ionizing radiation is addressed in specific OSHA standards for general industry, maritime, and construction. OSHA requires employers to protect workers from exposure to ionizing radiation sources that are not regulated by the Nuclear Regulatory Commission (NRC) or other federal agencies, such as x-ray equipment, some accelerators, incidental accelerator-produced radioactive materials, ion implanters, and some naturally-occurring radioactive material (NORM).
For jurisdictional information, see OSHA’s “Memorandum of Understanding between the U.S. Nuclear Regulatory Commission and the Occupational Safety and Health Administration.” Also, see the August 16, 1989, OSHA letter of interpretation on 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 1910.1096 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
For general industry, marine terminals, and longshoring:
- Employee exposure to ionizing radiation must be kept at or below limits. [1910.1096(b)]
- Employee exposure to airborne radioactive material must be kept at or below the limits. [1910.1096(c)]
- Surveys must be made as necessary to comply with the standard. [1910.1096(d)]
- Employees are required to be supplied and use appropriate personnel monitoring equipment, such as film badges, pocket chambers, pocket dosimeters, or film rings, if criteria are met. [1910.1096(d)]
- Caution signs, labels, and signals must meet requirements at 1910.1096(e). Exceptions are listed at 1910.1096(g) and (h).
- 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.
- NRC regulation 10 CFR 20 must be met if applicable. State ionizing radiation regulations (as listed at 1910.1096(p)(3) must be met if applicable. If not covered by 10 CFR 20 or state ionizing regulations, then personnel instruction and posting requirements must be met. [1910.1096(i)]
- Radioactive materials stored in a non-radiation area shall be secured against unauthorized removal from the place of storage. [1910.1096(j)]
- Radioactive material may not be disposed of except by transfer to an authorized recipient or in a manner approved by the NRC or state named at 1910.1096(p)(3). [1910.1096(k)]
- When employees are not protected by NRC 10 CFR 20, under 1910.1096(p)(2), or under laws/regulations of states listed at 1910.1096(p)(3), employers must do the following if an incident involving radiation exceeds certain limits listed in the standard:
- Notify OSHA by phone/telegraph of the any incident involving radiation which exceeds exposure limits. [1910.1096(l)]
- Submit a written report within 30 days of the incident. [1910.1096(m)(1)]
- Notify the exposed individual in writing. [1910.1096(m)(2)]
- 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)]
Note: Paragraph 1910.1096(p) goes over several scenarios where OSHA would deem the employer to be in compliance with the requirements of 1910.1096 with respect to possession and use of certain radiation sources or materials. The scenarios relate to NRC licenses or contracts and state licenses or source registration.
For ship repairing and shipbuilding:
- Applicable provisions of NRC 10 CFR 20 must be met for activities involving the use of or exposure to sources of ionizing radiation. [1915.57]
- A competent person specially trained in proper and safe operation must perform activities that involve the use of radioactive materials, whether or not under license of the NRC. [1915.57]
- Only licensed persons (or competent persons under direction of the licensee) may perform any work where materials are used under NRC license. [1915.57]
For construction:
- OSHA 1910.1096(a) to (p) must be met. [1926.53]
- When performing construction or related activities involving the use of ionizing radiation sources, pertinent requirements of NRC 10 CFR 20 related to protections against worker radiation exposure must be met. [1926.53(a)]
- A competent person specially trained in proper and safe operation must perform activities that involve the use of radioactive materials or x-rays, whether or not under license of the NRC. [1926.53(b)]
- Only licensed persons (or competent persons under direction of the licensee) may perform any work where materials are used under NRC license. [1926.53(b)]
