Health Hazard Assessment (HHA)

Hazard Category - Radiation Energy

Last Updated: August 02, 2018
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​Information on radiation energy.


Data Requirements and Initial Recommendations.
(1) Request an evaluation of improved, new, or commercial equipment/systems containing sources of ionizing radiation prior to purchase and use by the Army (reference 1).  The POC for ionizing radiation assessments and surveys is the Army Public Health Center Health Physics Program.

(2) Provide a detailed list of all sources of ionizing radiation.  Provide the information described below to this Center to support a definitive HHA.

     (a) For radioactive material:  the isotope(s), chemical or physical form, amount of isotope in each system and whether the source is sealed, unsealed, plated or foil.

     (b) For devices that emit ionizing radiation:

             i. For x-ray devices:  provide operating parameters, radiation output, and a description of any inherent shielding
                or beam filtration.
             ii. For a neutron source:  provide operating parameters, neutron emission rate, and average energy emitted.

     (c) Verification that x-ray devices meet applicable 21 Code of Federal Regulations (CFR) requirements or appropriate American National Standards Institute requirements.

     (d) Verification that radioactive material sources meet Title 10, CFR requirements.

     (e) Verification that a Nuclear Regulatory Commission radioactive material license or a Department of the Army Radiation Authorization is obtained, where required, for applicable sources of radioactive material and/or an x-ray device.

     (f) Development of standard operational procedures for production and deployment.

     (g) Storage, use, maintenance, disposal and special handling requirements.

(3) Eliminate/control exposures to ionizing radiation sources to the crew, passengers, and maintainers to the maximum extent feasible during design, manufacture and installation of commercial or government equipment containing ionizing radiation sources (reference 2).

Health Effects.
Exposure to ionizing radiation resulting in an absorbed dose may cause adverse biological effects to living tissue.  The nature of these effects depends on the amount of radiation absorbed, the rate at which it is absorbed, and on the biological tissues that are affected.  For low doses of ionizing radiation, the primary effect of interest is an increased risk of developing cancer in the future.  Genetic effects (effects that appear in future generations) are thought to be possible, however they have not been observed in human populations exposed to ionizing radiation.  Title 10, CFR, Army Regulation 385-10, and Department of the Army Pamphlet (DA PAM) 385-24, provide the ionizing radiation safety requirements and exposure limit criteria for personnel potentially exposed to ionizing radiation (references 3, 4, and 5).

Medical Criteria.
Regulatory radiation dose limits have been established for occupationally exposed individuals to prevent or minimize potential health risks. The primary limit is an effective whole-body dose not exceeding 50 millisievert (mSv) (5000 millirem (mrem)) per year.  Any occupationally exposed individual who is likely to receive a dose (from external sources) in excess of 5 mSv (500 mrem) per year must be issued an individual dosimeter to monitor his/her ionizing radiation dose.

(1) Memorandum, Office of the Chief of Staff, DACS-SF, subject:  Eliminate Hazards Through Design Selection, 10 Jun 04.

(2) Army Regulation (AR) 40-5, Preventive Medicine, 25 May 07.

(3) Title 10, Code of Federal Regulations (CFR), Energy, 1 Jan 11.

(4) Department of the Army Pamphlet (DA PAM) 385-24, Army Radiation Safety Program, (RAR) 26 Mar 09.

(5) Army Regulation (AR) 385-10, The Army Safety Program, (RAR) 03 Sep 09.

Supplemental References.
(1) American National Standards Institute (ANSI) N43.3-2008, Installations Using Non-Medical X-Ray and Sealed Gamma-Ray Sources, Energies Up to 10 MeV, American National Standards Institute, 1 Jan 08.

(2) American National Standards Institute (ANSI) N43.17-2009, Radiation Safety for Personnel Security Screening Systems Using X-rays or Gamma Radiation, American National Standards Institute, 1 Aug 09.

(3) Department of the Army Pamphlet (DA PAM) 40-18, Personnel Dosimetry Guidance and Dose Recording Procedures for Personnel Occupationally Exposed to Ionizing Radiation, 30 Jun 95.

(4) Title 21, Code of Federal Regulations (CFR), Chapter I, Subchapter J, Radiological Health, 1 Apr 11.

(5) Department of Defense Instruction (DoDI) 6055.8, Occupational Ionizing Radiation Protection Program, 15 Dec 09.

(6) American National Standards Institute/Health Physics Society (ANSI/HPS) N13.41 1997, Criteria for Performing Multiple Dosimetry, American National Standards Institute, 1997.

(7) International Commission on Radiological Protection (ICRP) Publication Number 26, International Commission on Radiological Protection, Recommendations of the International Commission on Radiological Protection, 1977.

(8) International Commission on Radiological Protection (ICRP) Publication Number 60, International Commission on Radiological Protection, 1990 Recommendations of the International Commission on Radiological Protection, 1991.

(10) Shleien, B. [ed.], The Health Physics and Radiological Health Handbook, 3rd Edition, Jan 98.

(11) United States Environmental Protection Agency (EPA), Federal Guidance Report No. 11, Limiting Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion, and Ingestion, Sep 88.

(12) Cember, H., Introduction to Health Physics, Fourth Edition, Jul 08.

(13) National Council of Radiation Protection and Measurements, Commentary No. 16, Screening of Humans for Security Purposes Using Ionizing Radiation Scanning Systems, 2003.

(14) Army Regulation (AR) 40-10, Health Hazard Assessment Program in Support of the Army Acquisition Process, 27 Jul 07.

(15) DA PAM 40-11, Preventive Medicine, (RAR) 19 Oct 09.

(16) Technical Manual (TM) 1-1500-335-23 (also known as TO 33B-1-1), Non-Destructive Inspection Methods, Basic Theory, 15 Jun 07.



Data Requirements and Initial Recommendations.
(1) Contact the Army Public Health Center (APHC) Nonionizing Radiation Division (NRD) to request a laser/optical radiation hazard evaluation on laser/optical radiation sources, including those previously evaluated by NRD for another U.S. Army program or those previously evaluated by the U.S. Navy or Air Force, during RDT&E and prior to purchase and use by the Army in accordance with Department of the Army Pamphlet (DA PAM) 40-11 (reference 1).  An initial paper analysis should be completed and followed up with an evaluation of the hardware, when available. 

(2) Provide a complete list of laser/optical radiation sources used in/on each piece of equipment to APHC to support a definitive HHAR on each item. For each laser/optical radiation source, provide a technical POC, mode of operation (continuous wave, single pulse, or multiple pulse), primary use, transmitter wavelength, maximum output power, maximum energy per pulse, pulse width at ½ power points, maximum pulse repetition frequency, distance from aperture to beam-waist, total pointing error (TPE) in μrad, exit beam diameter at 1/e points, beam divergence at 1/e points, beam distribution, beam profile, and laser medium.  Also provide details on day-view optics (i.e., magnifying power, laser protection, and boresighting procedures) and safety features/Food and Drug Administration required performance requirements (e.g., interlocks).

Health Effects.
Although new uses for laser/optical sources are being developed every day, most materiel will likely employ one of the following military laser/optical source applications; laser rangefinder/designator/illuminator/pointer, Multiple Integrated Laser Engagement System (MILES) training laser, LIDAR and LADAR, nonlethal weapons, UV lamps for medical and biological testing, searchlights, flash devices, welding/cutting arcs, arc lamps, and other high intensity optical sources.  For most sources, the effects of exposure are determined by the wavelength and dose received by the Soldier and is usually limited to the skin and eye.  The eye is the most sensitive, with exposed skin being vulnerable to only higher-powered lasers.

Medical Criteria.
(1) Optical radiation should not be confused with ionizing radiation, such as X-rays and gamma rays.  There are two damage mechanisms:  thermal and photochemical.  Thermal effects are brought about by a temperature increase, while photochemical effects are a chemical change caused by the absorption of photons.  Photochemical effects are linearly additive up to the expected or anticipated exposure duration.

(2) Optical radiation hazards exist only along the beam path, unlike radioactive materials that emit radiation in all directions.  Lasers and high intensity optical radiation sources that are focused by the eye (400-1,400 nanometers (nm)) require very little energy to cause injury.  This is due to the concentration of the beam by the eye, especially in the case of lasers, which are concentrated at the retina by a factor of approximately 100,000 times.  This is similar to burning a piece of paper with focused sunlight using a magnifying glass.  Some retinal hazard can be present from lasers and high intensity optical sources that emit at wavelengths < 400 nm, though these wavelengths are mostly absorbed in the cornea and lens, where they can also pose a hazard.  For lasers and high intensity optical sources that emit at wavelengths greater than 1400 nm, the emission is absorbed mostly in the cornea.  These wavelengths permit higher irradiances or radiant exposures because they are not focused by the eye, but these wavelengths can still pose a hazard to the cornea and are not necessarily "eye safe."

(3) In addition to the focusing by the eye, lasers and optical sources that emit wavelengths greater than 700 nm are invisible.  Since a person cannot see these wavelengths, he or she may be exposed to the beam longer than what would be expected for viewing visible radiation.  A person viewing a visible-emitting laser or high-intensity optical source may be expected to fixate on the same point in space (and, as a result, receive exposure to the same part of the eye) for no greater than 0.25 seconds, but a person viewing a source emitting greater than 700 nm could be expected to fixate on a given point for 10 seconds.

(1) Department of the Army Pamphlet (DA PAM) 40-11, Preventive Medicine, (RAR) 19 Oct 09.

Supplemental References.
(1) Department of Defense Instruction (DODI) 6055.15, DoD Laser Protection Program, 4 May 07.

(2) Army Regulation (AR) 385-10, The Army Safety Program, (RAR) 03 Sep 09.

(3) DA PAM 385-24, The Army Radiation Safety Program, 24 Aug 07.

(4) Military Standard (MIL-STD) 1425A, DoD Design Criteria Standard, Safety Design Requirements for Military Lasers and Associated Support Equipment, 30 Aug 91.

(5) American National Standards (ANSI), "Safe Use of Lasers," American National Standard Z136.1 - 2007, Orlando, FL, Laser Institute of America.

(6) International Electrotechnical Commission (IEC), "Safety of Laser Products – Part 1: Equipment classification, requirements, and user's guide," IEC 60825-1 Ed. 2, 2007-03, Geneva, Switzerland, IEC.

(7) Technical Bulletin Medical (TB MED) 524, Control of Hazards to Health From Laser Radiation, 31 Jan 06.

(8) Title 21, Code of Federal Regulations (CFR), 2009 rev. Part 1040, Performance Standards for Light Emitting Products.

(9) American Conference of Government Industrial Hygienists (ACGIH), Threshold Limit Values and Biological Exposure Indices, Updated Annually, Cincinnati, OH, ACGIH.

(10) ANSI / Illuminating Engineering Society of North America (IESNA), "Recommended Practice for Photobiological Safety for Lamps and Lamp Systems - General Requirements", ANSI / IESNA RP-27. 1-05, New York, NY, IESNA.



Data Requirements and Initial Recommendations.
(1) Contact the APHC NRD to request a radio frequency radiation (RFR) survey of new RFR sources being developed during research, development, test and evaluation (RDT&E) and prior to purchase and use by the Army in accordance with Department of the Army Pamphlet (DA PAM) 40-11 (reference 1). In lieu of an RFR survey by APHC NRD, provide data that supports an RFR assessment of these sources or provide an equivalent RFR survey from another Department of Defense Center.

(2) Provide a complete list of RFR sources used in/on each equipment variant to APHC NRD to support a definitive Health Hazard Assessment (HHA). For non-government furnished equipment that emits RFR, provide a technical point of contact, frequency, peak and average power output, pulse repetition frequency, pulse width, duty cycle, antenna type, size, and gain, transmission line length and losses, and the source's location on the equipment.  See Department of Defense Form (DD Form) 1494 for additional information and guidance (reference 2).

Health Effects.
The primary effect of absorbed RFR energy is in-vivo temperature increase.  Secondary effects (i.e., those arising from temperature increases) may include tissue damage with the lens of the eye being the most sensitive part of the body.  Electromagnetic energy can also induce electrical currents, stimulating nerves or muscles.  In some RF environments, contact with excessively high RF voltages may result in an RF shock or burn.

Medical Criteria.
(1) The Department of Defense and Army standards (references 1–6) for permissible exposure to electromagnetic fields (EMFs) and radio frequency radiation (RFR) in the 0 to 300 gigahertz (GHz) frequency spectrum is based on those of the American National Standards Institute/Institute of Electrical and Electronics Engineers C95.1 and C95.6 standards (references 7 and 8).  These standards are based on established adverse health effects and specify permissible exposure limits (PEL) or maximum permissible exposures (MPE) for the protection of personnel.  There are no expectations that any adverse health effects will occur with exposures that are within the MPEs, even under repeated or long-term exposure conditions.  A minimum safety factor of ten is incorporated into these standards.  These MPEs are also assessed with reference to an averaging time that varies with frequency. 

(2) The MPEs are given in terms of root mean square (rms) electric field strengths in volts per meter (V/m), rms magnetic field strengths in amperes per meter (A/m), plane-wave equivalent power densities in either milliwatts per square centimeter (mW/cm²) or watts per square meter (W/m²), or the induced and contact currents in amperes (A).  The MPEs at frequencies below 5 MHz are established to limit adverse health effects due to electrostimulation.  The MPEs in the frequencies between 100 kHz and 3 GHz were derived to limit the specific absorption rates (SARs) to no greater than 0.4 watts per kilogram (W/kg) for whole-body exposure or 10 W/kg averaged over any 10 g  of tissue, for localized exposure.  In the transition region between 100 kHz and 5 MHz, the MPE must protect against both heating effects and electrostimulation.  The MPEs in the frequencies between 3 GHz and 300 GHz are established to limit adverse health effects due to incident power density.  Between 3 GHz and 6 GHz, the MPEs must demonstrate compliance to the standards by incident power density or local SAR.  An open voltage of 140 V (rms) in RF fields is a conservative criterion used to define a potential RF shock or burn hazard situation.

(1) Department of the Army Pamphlet (DA PAM) 40-11, Preventive Medicine, (RAR 19 Oct 09), 22 Jul 05.

(2) Department of Defense (DD) Form 1494, Application for Equipment Frequency Allocation, Aug 96.

(3) Army Regulation (AR) 385-10, The Army Safety Program, 27 Nov 13.

(4) AR 40-5, Preventive Medicine, 25 May 07.

(5) Department of Defense Instruction (DoDI) 6055.11, Protection of DoD Personnel from Electromagnetic Fields, 19 Aug 09.

(6) Department of the Army Pamphlet (DA PAM) 385–24, The Army Radiation Safety Program, 30 Nov 15. 

(7) Institute of Electrical and Electronics Engineers (IEEE) C95.1-2005, IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz, 19 Apr 06.

(8) IEEE C95.6-2002 IEEE Standard for Safety Levels with Respect to Human Exposure to Electromagnetic Fields, 0–3 kHz, 23 Oct 02.

Supplemental References.
(1) Technical Bulletin Medical (TB MED) 523, Control of Hazards to Health From Microwave and Radio Frequency Radiation and Ultrasound, Jul 80.

(2) MIL-STD-464C, DOD Interface Standard, Electromagnetic Environmental Effects, Requirements for Systems, 1 Oct 10.

(3) Title 29, Code of Federal Regulations (CFR) 1910.97, Nonionizing Radiation.