4
Current Paradigms for Radiation Protection in the Army

The Army has two separate programs to control radiation exposure to soldiers. One is applied to those individuals whose duties parallel those of civilian radiation workers. These include military personnel such as x-ray technicians, radiologists who do radiological examinations, researchers using radioisotopes, and technicians who maintain radioactive commodities such as Geiger counter calibration sources. The Army's other radiation protection program is intended to apply only during situations of extremely high radiation exposure, such as nuclear war.

Occupational Exposure

In peacetime, soldiers who are considered to be at risk of exposure to radiation in the execution of their duties are safeguarded by radiation protection regulations (DoDI, 1996) that are comparable to those of their civilian counterparts. The radiation limits prescribed by these regulations (see examples in Table 2-3) are derived from U.S. Nuclear Regulatory Commission (USNRC) standards, which for the most part10 reflect recommendations of the ICRP and NCRP.

Radioactive commodities in the Army are controlled, as they are in civilian industrial operations, under licenses issued by the USNRC. Exposures that could result from the fabrication, maintenance, or application of these radioactive commodities are subject to control under civilian regulations (CFR, 1991) that

10  

 There are significant differences between ICRP and NCRP and NRC in the values of WR, some dose limits, and in some other areas.



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--> 4 Current Paradigms for Radiation Protection in the Army The Army has two separate programs to control radiation exposure to soldiers. One is applied to those individuals whose duties parallel those of civilian radiation workers. These include military personnel such as x-ray technicians, radiologists who do radiological examinations, researchers using radioisotopes, and technicians who maintain radioactive commodities such as Geiger counter calibration sources. The Army's other radiation protection program is intended to apply only during situations of extremely high radiation exposure, such as nuclear war. Occupational Exposure In peacetime, soldiers who are considered to be at risk of exposure to radiation in the execution of their duties are safeguarded by radiation protection regulations (DoDI, 1996) that are comparable to those of their civilian counterparts. The radiation limits prescribed by these regulations (see examples in Table 2-3) are derived from U.S. Nuclear Regulatory Commission (USNRC) standards, which for the most part10 reflect recommendations of the ICRP and NCRP. Radioactive commodities in the Army are controlled, as they are in civilian industrial operations, under licenses issued by the USNRC. Exposures that could result from the fabrication, maintenance, or application of these radioactive commodities are subject to control under civilian regulations (CFR, 1991) that 10    There are significant differences between ICRP and NCRP and NRC in the values of WR, some dose limits, and in some other areas.

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--> tend to implement the general philosophy and practices espoused by the ICRP and NCRP. Army-specific requirements for control and safe handling of radioactive commodities are under the jurisdiction of the Army Materiel Command (AMC, 1980), while the protection of individual soldiers is a medical function under the purview of the Office of the Surgeon General (OTSG, 1995a, 1995b). Two OTSG medical documents constitute the bulk of the individual radiation protection program in the Army. Although the regulations provide a measure of radiation protection to soldiers that parallels that of civilians in similar environments and circumstances, they do not extend that same protection in militarily unique missions, as the following excerpt from Army (Medical) Regulation 40-14 demonstrates: Applicability. This regulation applies to Department of the Army (DA) and Defense Logistics Agency (DLA) installations and activities. This includes the Army National Guard of the United States (ARNGUS), U.S. Army Reserve (USAR), and civilians under contract with the DA or DLA who perform tasks involving occupational exposure to DA and DLA controlled radioactive material or radiation-producing devices. This publication is not applicable during mobilization or anytime the U.S. Army adopts a state of readiness directly preparatory to actual or imminent armed conflict in a geographical zone where peacetime occupational radiation exposure conditions cannot reasonably be construed to prevail. In particular, this regulation remains applicable to DA and DLA personnel deployed on either humanitarian or peacekeeping missions where the degree of readiness to respond to hostile fire requires the availability of radioactive commodities, such as depleted uranium ammunition, as a contingency. This regulation does NOT apply to the following: (1)   Personnel exposed to ionizing radiation and radioactive materials resulting from the use of ionizing radiation sources and devices in geographical areas or zones where— (a)   Hostile fire or combat already exists or is strongly anticipated to occur, or (b)   Combat missions are intentionally going to be conducted by Department of Defense personnel. (2)   Patients exposed to ionizing radiation in the course of medical and dental examination, diagnosis, or treatment. This exception does not apply to health care providers. (3)   Human research subjects exposed to ionizing radiation in the course of voluntary participation in medical research programs. (4)   Doses received from natural background radiation. [Emphasis added.]

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--> High-Level Exposures in Nuclear War Exposure to radiation anticipated during times of war has been assumed to be the result of nuclear weapon detonation. Training soldiers to operate in a nuclear environment has been conducted since the advent of nuclear weapons and continues to this day (HQDA, 1983, 1992, 1993). Radiation protection practice under these conditions has been driven by the need for soldiers to survive to accomplish their immediate mission. In this scenario, the risk of stochastic effects, including cancer, has been a secondary concern. NATO Standardization Agreement 2083 (NATO, 1986) defines exposure criteria for use in planning for the commitment of troops to a radiologically contaminated area that would result in high-level exposures to radiation. These criteria are implemented in the U.S. Army by Field Manual 3-3-1 (HQDA, 1994). Their purpose is to control the cumulative radiation dose received by combat units. One of four radiation exposure status categories (Table 4-1) is assigned to a unit, depending on its cumulative dose. The unit dose is an average of the doses to individuals in the unit who have dosimeters. Protocol requires that during operations in a nuclear environment, individual dosimeters be read daily and the results passed up the chain of command. Records of summary exposure data are maintained at battalion level for subordinate company and platoon-sized units and are then forwarded to higher commands, which keep more broadly aggregated records. Currently, the Army does not record doses on individual soldiers who are exposed to battlefield radiation. Doctrine requires that 2 soldiers per squad (about 25 percent) have self-reading dosimeters; there are usually 3 squads in a platoon. Until it implements individual dosimetry, the Army assumes that each soldier gets an individual dose equal to that of the average for the platoon (HQDA, 1994). The Army plans to equip each soldier, eventually, with a dosimeter, but the type expected to be deployed (DT-236) will be useful for recording, doses only in excess of about 100 mSv. Since the platoon is the lowest aggregate level for which records are kept, replacements for exposed units are made at the platoon level. When a soldier leaves an exposed unit, the radiation exposure status (RES) for that platoon (not the soldier's individual dose) is noted in the soldier's personnel file. Where possible, soldiers are reassigned to platoons with the same RES category, which, although creating severe management problems, is intended to keep personnel from incapacitation due to overexposure to radiation.

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--> Table 4-1. Nuclear Radiation Exposure Status and Degree of Risk Exposure Radiation Status Categorya,b Total Past Cummulative Dosec(cGy) Possible exposure criteria for a single operation that will not result in exceeding the dose criteria for the stated degree of riskd,e(cGy) RES-0 No exposure Negligible risk: ≤ 50 [500 mGy]     Moderate risk: ≤ 70 [700 mGy]     Emergency risk: ≤ 150 [1500 mGy] RES-1 More than 0, but less than or equal to 70 [700 mGy] Negligible risk: ≤ 10 [100 mGy]     Moderate risk: ≤ Z 30 [300 mGy]     Emergency risk: ≤ 110 [1100 mGy] RES-2 More than 70 [700 mGy], but less than or equal to 150 [1500 mGy] Any further exposure is considered to exceed a negligible or moderate risk.     Emergency risk: ≤ 40 [400 mGy] RES-3 More than 150 [1500 mGy] Any further exposure will exceed the emergency risk. a Radiation status categories are based on previous exposure to radiation. b Reclassification of units from one radiation status category to a less serious one is made by the commander, upon advice of the surgeon, after ample observation of actual state of health of exposed personnel. c All exposures to radiation are considered total body and simply additive. No allowance is made for body recovery from radiation injury. d Risk levels are graduated within each status category to provide more stringent criteria as the total radiation dose accumulated becomes more serious. The exposure criteria given for RES-1 and RES-2 units should be used only when the numerical value of a unit's total past cumulative dose is unknown. e Each of the degrees of risk can be applied to radiation hazards resulting from enemy or friendly weapons, or both, and from initial nuclear radiation resulting from planned friendly supporting fire. SOURCE: HQDA. Nuclear Contamination Avoidance, Field Manual 3-3-1. Washington, D.C.: Headquarters, Department of the Army, 1994. Summary of Existing Army Programs The discussion thus far demonstrates a wide gap in the Arm's radiation protection program. The occupational radiation protection program limits exposures to 50 mSv annually. The Army's Operational Exposure Guidance (Table 4-1) considers exposures a factor of 10 higher than that (500 mGy) to be in the negligible risk category. Therefore, for situations for which there is potential for exposures between 50 and 500 mGy, there exists a range of doses for which there is no guidance. It was to fill that gap that the NATO team of experts proposed Table 4-2 below.

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--> This table was integrated into ACE Directive 80-63 as guidance for radiation protection to the troops assigned to the peacekeeping mission to Bosnia. The next section describes that document, which appears in its entirety in the Appendix.

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--> Table 4-2. Operational Exposure Guidance for Low-Level Radiation Total Cumulative Dose (cGy)a,b,c RES Category Stated,e Actions < 0.05 cGy [0.5 mGy] 0 No risk   None 0.05 to 0.5 cGy [0.5–5 mGy] 1A Normal risk   Record individual dose readings and Initiate periodic monitoring 0.5 to 5 cGy [5–50 mGy] 1B Minimal risk   Record individual dose readings and continue monitoring Initiate rad survey Prioritize tasks Establish dose control measures as part of operations 5 to 10 cGy [50–100 mGy] 1C Limited risk   Record individual dose readings Continue monitoring and update survey Continue dose control measures Execute priority tasks only (see Note f) 10 to 25 cGy [100–250 mGy] See Note g 1D Increased risk   Record individual dose readings Continue monitoring and update survey Continue dose control measures Execute critical tasks only (see Note g) 25 to 70 cGy [250–700 mGy] See Note h 1E Significant risk   Record individual dose readings Continue monitoring and update survey Continue dose control measures Execute critical tasks only

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--> Total Cumulative Dose (cGy)a,b,c RES Category Stated,e Actions a Dose is uniform to the entire body due to whole body irradiation. This table does not consider the intake of radioactive material. This is assumed due to employment of effective respiratory protection and other measures. b All doses should be kept as low as reasonably achievable (ALARA). This will reduce individual soldier risk as well as retain maximum operational flexibility for future employment of exposed soldiers. c The use of the measurement millisieverts (mSv) is preferred in all cases. However, due to the fact that normally the military has only the capability to measure Centigray (cGy), as long as the ability to obtain measurements in mSv is not possible, ACE forces will use cGy. For whole body Gamma irradiation: 1 cGy = 10 mSv. d Risk is of long-term health consequences primarily induction of fatal cancer starting two years postexposure. Total lifetime risk is assumed to be four to seven percent per 100 cGy (= 1000 mSv). This is in addition to the 20–25% incidence of fatal cancer among the general-population. Additional health risks that may occur are teratogenesis and mutagenesis and their associated psychological and social consequences. e It must be noted that higher radiation dose rates produce proportionally more other health risk than the same total dose given over a longer period. f Examples of priority tasks are those missions to avert danger to persons or to prevent damage from spreading. Examples of critical tasks are those missions to save human lives. g During peacetime this dose shall not be exceeded except to save human lives. h RES category 1E covers a wide range of dose and its lower level (25 cGy = 250 mSv) is the peacetime maximum operational dose in many NATO nations. This category is normally only applicable in wartime. Intentional exposures to doses in this category (25–70 cGy = 250–700 mSv) require additional justification. SOURCE: NATO. ACE policy for defensive measures against low-level radiological hazards during military operations. ACE Directive Number 80-69. Brussels, Belgium: SHAPE (Supreme Headquarters Allied Powers Europe), 2 August 1996.